The information in this proxy statement/prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This proxy statement/prospectus is not an offer to sell and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED JULY 27, 2023

PROPOSED MERGER

YOUR VOTE IS VERY IMPORTANT

To the Stockholders of Frequency Therapeutics, Inc. and Korro Bio, Inc.,

Frequency Therapeutics, Inc., a Delaware corporation, or Frequency, and Korro Bio, Inc., a Delaware corporation, or Korro Bio, entered into an Agreement and Plan of Merger, or the Merger Agreement, on July 14, 2023, pursuant to which a direct, wholly owned subsidiary of Frequency, Frequency Merger Sub, Inc., or Merger Sub, will merge with and into Korro Bio, with Korro Bio surviving as a direct, wholly owned subsidiary of Frequency, and the surviving corporation of the merger, which transaction is referred to herein as the Merger. Frequency following the Merger is also referred to herein as the combined company.

At the time the certificate of merger is filed with and accepted by the Secretary of State of the State of Delaware, or the Effective Time, as described in more detail in the section titled “The Merger—Effective Time of the Merger” beginning on page 185 of the accompanying proxy statement/prospectus, each share of Korro Bio common stock will be converted into the right to receive a number of shares of Frequency common stock equal to the total number of shares of Frequency common stock to be issued in the Merger multiplied by the applicable Korro Bio stockholder’s percentage interest in Korro Bio as set forth in the allocation certificate to be provided by Korro Bio, or the Allocation Certificate, and as described in more detail in the section titled “The Merger Agreement—Allocation Certificate” beginning on page 191 of the accompanying proxy statement/prospectus. The Korro Bio common stock that will be converted in the Merger includes Korro Bio common stock issued pursuant to the subscription agreement by and among Korro Bio and certain parties to purchase shares of Korro Bio’s common stock for an aggregate purchase price of approximately $117.3 million, which transaction is referred to as the Pre-Closing Financing. If any Korro Bio common stock outstanding immediately prior to the Effective Time is unvested or is subject to a repurchase option or a risk of forfeiture under any applicable agreement with Korro Bio, then the shares of Frequency common stock issued in exchange for such shares of Korro Bio common stock will to the same extent be unvested and subject to the same repurchase option or risk of forfeiture, and such shares of Frequency common stock will be marked with appropriate legends.

In connection with the Merger, each option to purchase shares of Korro Bio common stock outstanding as of immediately prior to the Effective Time shall automatically be converted, at the Effective Time, into an option to acquire the number of shares of Frequency common stock equal to the number of shares of Korro Bio common stock subject to such option as of immediately prior to the Effective Time multiplied by the exchange ratio formula in the Merger Agreement and rounding that result down to the nearest whole number of shares.

Each share of Frequency common stock that is issued and outstanding at the Effective Time will remain issued and outstanding and such shares, subject to a proposed reverse stock split of Frequency’s issued and outstanding common stock at a ratio ranging from any whole number between 1-for-     and 1-for-     as determined by the Frequency board of directors in its discretion, or Reverse Stock Split, as described in the section titled “Matters Being Submitted to a Vote of Frequency Stockholders—Proposal No. 2: Approval of the Amendment to the Restated Certificate of Incorporation of Frequency Effecting the Reverse Stock Split” beginning on page 234 will be unaffected by the Merger. Each outstanding option to purchase shares of Frequency common stock, which is referred to as a Frequency Option, will remain outstanding and such options, subject to proportionate adjustment in accordance with the terms of Frequency’s 2019 Incentive Award Plan or

2014 Stock Incentive Plan, as applicable, to reflect the Reverse Stock Split and the issuance of the contingent value rights, or CVRs, will be unaffected by the Merger, provided that each Frequency Option that is outstanding and unvested will vest in full immediately prior to the Effective Time. Each restricted stock unit covering shares of Frequency common stock that is outstanding will remain outstanding and such restricted stock units, subject to proportionate adjustment in accordance with the terms of Frequency’s 2019 Incentive Award Plan to reflect the Reverse Stock Split and issuance of the CVRs, will be unaffected by the Merger, provided that each restricted stock unit award that vests solely based on the holder’s continued employment or service will vest in full immediately prior to the Effective Time.

Immediately after the Merger, Frequency securityholders as of immediately prior to the Merger are expected to own approximately 8% of the outstanding shares of the combined company on a fully-diluted basis and former Korro Bio securityholders (including purchasers in the Pre-Closing Financing) are expected to own approximately 92% of the outstanding shares of the combined company on a fully-diluted basis, subject to certain assumptions, including, but not limited to, Frequency’s net cash as of closing being equal to $25 million.

Shares of Frequency common stock are currently listed on The Nasdaq Global Select Market, or Nasdaq, under the symbol “FREQ.” Frequency intends to file an initial listing application for the combined company with the Nasdaq Stock Market LLC. After completion of the Merger, Frequency will be renamed “Korro Bio, Inc.” and it is expected that the common stock of the combined company will trade on Nasdaq under the symbol “KRRO.” On             , 2023, the last trading day before the date of the accompanying proxy statement/prospectus, the closing sale price of Frequency common stock was $             per share.

Frequency stockholders are cordially invited to attend the annual meeting of Frequency stockholders, or the Frequency Annual Meeting. Frequency is holding the Frequency Annual Meeting, on             ,             2023, at             Eastern Time, unless postponed or adjourned to a later date, in order to obtain the stockholder approvals necessary to complete the Merger or other matters. The Frequency Annual Meeting will be held entirely online. Frequency stockholders will be able to attend and participate in the Frequency Annual Meeting online by visiting www.proxydocs.com/FREQ where they will be able to listen to the meeting live, submit questions and vote. At the Frequency Annual Meeting, Frequency will ask its stockholders:

As described in the accompanying proxy statement/prospectus, certain Frequency stockholders who in the aggregate owned approximately 3.5% of the outstanding shares of Frequency as of July 14, 2023, and certain Korro Bio stockholders who in the aggregate owned approximately 98% of the outstanding shares of Korro Bio common stock as of July 14, 2023, are parties to stockholder support agreements with Frequency and Korro Bio, respectively, whereby such stockholders have agreed to vote in favor of the approval of the transactions contemplated therein, including, with respect to such Korro Bio stockholders, adoption of the Merger Agreement and approval of the Merger and, with respect to such Frequency stockholders, the issuance of Frequency common stock in the Merger pursuant to the Merger Agreement, subject to the terms of the support agreements. Following the effectiveness of the registration statement on Form S-4 of which the accompanying proxy statement/prospectus is a part and pursuant to the Merger Agreement, Korro Bio stockholders holding a sufficient number of shares of Korro Bio common stock to adopt the Merger Agreement and approve the Merger and related transactions will execute written consents providing for such adoption and approval.

After careful consideration, each of the Frequency and Korro Bio boards of directors have approved the Merger Agreement and have determined that it is advisable to consummate the Merger. The Frequency board of directors has approved the proposals described in the accompanying proxy statement/prospectus and unanimously recommends that its stockholders vote “FOR” the director nominee and “FOR” the other proposals described in the accompanying proxy statement/prospectus.

More information about Frequency, Korro Bio, the Merger Agreement and transactions contemplated thereby and the foregoing proposals is contained in the accompanying proxy statement/prospectus. Frequency urges you to read the accompanying proxy statement/prospectus carefully and in its entirety. IN PARTICULAR, YOU SHOULD CAREFULLY CONSIDER THE MATTERS DISCUSSED UNDER “RISK FACTORS” BEGINNING ON PAGE 32 OF THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS.

Frequency and Korro Bio are excited about the opportunities the Merger brings to Frequency’s and Korro Bio’s stockholders and thank you for your consideration and continued support.

Sincerely,

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of the accompanying proxy statement/prospectus. Any representation to the contrary is a criminal offense.

The accompanying proxy statement/prospectus is dated             , 2023 and is first being mailed to Frequency stockholders on or about             , 2023.

FREQUENCY THERAPEUTICS, INC.

75 HAYDEN AVENUE, SUITE 300

LEXINGTON, MA 02421

(781) 315-4600

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To the stockholders of Frequency Therapeutics, Inc., or Frequency:

NOTICE IS HEREBY GIVEN that the annual meeting of stockholders of Frequency, or the Frequency Annual Meeting, will be held on                 , 2023, at                 Eastern Time, unless postponed or adjourned to a later date. The Frequency Annual Meeting will be held entirely online. You will be able to attend and participate in the Frequency Annual Meeting online by visiting www.proxydocs.com/FREQ where you will be able to listen to the Frequency Annual Meeting live, submit questions and vote.

The Frequency Annual Meeting will be held for the following purposes:

Your vote is important. The affirmative vote of the holders of a majority in voting power of the votes cast affirmatively or negatively at the Frequency Annual Meeting by the holders entitled to vote thereon, assuming a quorum is present, is required for approval of Proposal Nos. 1, 4, 5, 6 and 7. The affirmative vote of the holders of a majority of the outstanding shares of Frequency common stock entitled to vote thereon is required for approval of Proposal No. 2. The plurality of the votes cast by the holders of shares present in attendance or represented by proxy at the Frequency Annual Meeting and entitled to vote on the matter, assuming a quorum is present, is required for approval of Proposal No. 3. Approval of Proposal No. 1 is a condition to the completion of the Merger. Therefore, the Merger cannot be consummated without the approval of Proposal Nos. 1 and 2.

Even if you plan to attend the Frequency Annual Meeting, Frequency requests that you sign, date and promptly return the enclosed proxy card or vote by mail or online to ensure that your shares will be represented at the Frequency Annual Meeting. You may change or revoke your proxy at any time before it is voted at the Frequency Annual Meeting.

FREQUENCY’S BOARD OF DIRECTORS HAS DETERMINED AND BELIEVES THAT EACH OF THE PROPOSALS OUTLINED ABOVE IS FAIR TO, IN THE BEST INTERESTS OF, AND ADVISABLE TO FREQUENCY AND ITS STOCKHOLDERS AND HAS APPROVED EACH SUCH PROPOSAL. FREQUENCY’S BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT FREQUENCY STOCKHOLDERS VOTE “FOR” EACH SUCH PROPOSAL.

By Order of Frequency’s Board of Directors,

David L. Lucchino

President and Chief Executive Officer

Lexington, MA

                , 2023

ABOUT THIS PROXY STATEMENT/PROSPECTUS

This document, which forms part of a registration statement on Form S-4 filed with the U.S. Securities and Exchange Commission, or the SEC, by Frequency Therapeutics, Inc., or Frequency, constitutes a prospectus of Frequency under the Securities Act of 1933, as amended, or the Securities Act, with respect to the shares of common stock of Frequency to be issued (or reserved for issuance) to the securityholders of Korro Bio, Inc., or Korro Bio, pursuant to the Agreement and Plan of Merger dated as of July 14, 2023, by and among Frequency, Korro Bio and Frequency Merger Sub, Inc., a direct, wholly owned subsidiary of Frequency, or Merger Sub, as it may be amended from time to time, or the Merger Agreement, pursuant to which Merger Sub will merge with and into Korro Bio, with Korro Bio surviving as a wholly owned subsidiary of Frequency, and the surviving corporation of the merger, or the Merger. This document also constitutes a proxy statement of Frequency under Section 14(a) of the Securities Exchange Act of 1934, as amended, or the Exchange Act. It also constitutes a notice of meeting with respect to the annual meeting of Frequency stockholders, or the Frequency Annual Meeting, at which Frequency stockholders will be asked to consider and vote, among other matters, on the issuance of the shares of Frequency common stock pursuant to the Merger Agreement and the change of control resulting from the Merger. Frequency following the Merger is referred to in this proxy statement/prospectus as the combined company.

Frequency has supplied all information contained in this proxy statement/prospectus relating to Frequency. Korro Bio has supplied all information contained in this proxy statement/prospectus relating to Korro Bio.

You should rely only on the information contained in this proxy statement/prospectus. Frequency and Korro Bio have not authorized anyone to provide you with information that is different from that contained in this proxy statement/prospectus. This proxy statement/prospectus is dated                 , 2023, and you should not assume that the information contained in this proxy statement/prospectus is accurate as of any date other than such date. Neither the mailing of this proxy statement/prospectus to Frequency stockholders nor the issuance by Frequency of shares of Frequency common stock pursuant to the Merger Agreement will create any implication to the contrary.

Except where otherwise noted, the information contained in this proxy statement/prospectus does not give effect to the proposed reverse stock split of Frequency’s issued and outstanding common stock at a ratio ranging from any whole number between 1-for-     and 1-for-     as determined by the Frequency board of directors in its discretion, or the proposed Reverse Stock Split, described in the section titled “Matters Being Submitted to a Vote of Frequency Stockholders — Proposal No. 2: Approval of the Amendment to the Restated Certificate of Incorporation of Frequency Effecting the Reverse Stock Split” beginning on page 234 of this proxy statement/prospectus.

Frequency and Korro Bio have proprietary rights to trademarks, trade names and service marks appearing in this proxy statement/prospectus that are important to their respective businesses. Solely for convenience, the trademarks, trade names and service marks may appear in this proxy statement/prospectus without the ^® and TM symbols, but any such references are not intended to indicate, in any way, that Frequency or Korro Bio forgo or will not assert, to the fullest extent under applicable law, their rights or the rights of the applicable licensors to these trademarks, trade names and service marks. All trademarks, trade names and service marks appearing in this proxy statement/prospectus are the property of their respective owners.

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TABLE OF CONTENTS

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iii

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Annex A—Agreement and Plan of Merger

Annex B—Opinion of Cowen and Company, LLC

Annex C—Form of Frequency Stockholder Support Agreement

Annex D—Form of Korro Bio Stockholder Support Agreement

Annex E—Form of Contingent Value Rights Agreement

Annex F—Form of Frequency Lock-Up Agreement

Annex G—Form of Korro Bio Lock-Up Agreement

Annex H—Certificate of Amendment Effecting the Reverse Stock Split

Annex I—2023 Stock Option and Incentive Plan

Annex J—2023 Employee Stock Purchase Plan

Annex K—Appraisal Rights (Section 262 of the Delaware General Corporation Law)

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CAUTIONARY STATEMENT CONCERNING FORWARD-LOOKING STATEMENTS

This proxy statement/prospectus contains forward-looking statements relating to Frequency, Korro Bio, the Merger, the combined company, and the other proposed transactions.

These forward-looking statements are based on current expectations and beliefs and involve numerous risks and uncertainties that could cause actual results to differ materially from expectations. These forward-looking statements should not be relied upon as predictions of future events as Frequency and Korro Bio cannot assure you that the events or circumstances reflected in these statements will be achieved or will occur. You can identify forward-looking statements by the use of forward-looking terminology including “believes,” “expects,” “may,” “will,” “should,” “seeks,” “intends,” “plans,” “pro forma,” “estimates” or “anticipates” or the negative of these words and phrases or other variations of these words and phrases or comparable terminology. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. Forward-looking statements include, but are not limited to, any statements regarding the strategies, prospects, plans, expectations or objectives of management of Frequency or Korro Bio for future operations of the combined company, the progress, scope or timing of the development of the combined company’s product candidates, the benefits that may be derived from any future products or the commercial or market opportunity with respect to any future products of the combined company, the ability of the combined company to protect its intellectual property rights, the anticipated operations, financial position, ability to raise capital to fund operations, revenues, costs or expenses of Frequency, Korro Bio or the combined company, statements regarding future economic conditions or performance, statements of belief and any statement of assumptions underlying any of the foregoing. Forward-looking statements may also include any statements regarding the approval and closing of the Merger, including the timing of the consummation of the Merger, Frequency’s ability to solicit a sufficient number of proxies to approve the Merger, satisfaction of conditions to the completion of the Merger, the expected benefits of the Merger, the ability of Frequency and Korro Bio to complete the Merger and any statement of assumptions underlying any of the foregoing.

For a discussion of the factors that may cause Frequency, Korro Bio or the combined company’s actual results, performance or achievements to differ materially from any future results, performance or achievements expressed or implied in such forward-looking statements, or for a discussion of risks associated with the ability of Frequency and Korro Bio to complete the Merger and the effect of the Merger on the business of Frequency, Korro Bio and the combined company, see the section titled “Risk Factors” beginning on page 32 of this proxy statement/prospectus.

If any of these risks or uncertainties materialize or any of these assumptions prove incorrect, the results of Frequency, Korro Bio or the combined company could differ materially from the forward-looking statements. All forward-looking statements in this proxy statement/prospectus are current only as of the date of this proxy statement/prospectus. Frequency and Korro Bio do not undertake any obligation to (and expressly disclaim any such obligation to) publicly update any forward-looking statement to reflect events or circumstances after the date of this proxy statement/prospectus or to reflect the occurrence of unanticipated events.

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QUESTIONS AND ANSWERS

The following section provides answers to frequently asked questions about the Merger, general information about the Frequency Annual Meeting and voting. For some questions, this section provides only summary information. For a more complete response to these questions and for additional information, please refer to the cross-referenced sections.

Questions and Answers About the Merger

Q:    What is the Merger?

A: Frequency and Korro Bio have entered into the Merger Agreement, dated as of July 14, 2023, a copy of which is attached as Annex A to this proxy statement/prospectus. The Merger Agreement contains the terms and conditions of the proposed business combination of Frequency and Korro Bio. Pursuant to the Merger Agreement, Merger Sub, a direct, wholly owned subsidiary of Frequency, will merge with and into Korro Bio, with Korro Bio surviving as a wholly owned subsidiary of Frequency and the surviving corporation. In connection with the Merger, Frequency will change its corporate name to “Korro Bio, Inc.”

At the Effective Time, each share of Korro Bio common stock will be converted into the right to receive a number of shares of Frequency common stock equal to the total number of shares of Frequency common stock to be issued in the Merger multiplied by the applicable Korro Bio stockholder’s percentage interest in Korro Bio as set forth in the Allocation Certificate, and as described in more detail in the section titled “The Merger Agreement—Allocation Certificate” beginning on page 191 of the accompanying proxy statement/prospectus. If any Korro Bio common stock outstanding immediately prior to the Effective Time is unvested or is subject to a repurchase option or a risk of forfeiture under any applicable agreement with Korro Bio, then the shares of Frequency common stock issued in exchange for such shares of Korro Bio common stock will to the same extent be unvested and subject to the same repurchase option or risk of forfeiture, and such shares of Frequency common stock will be marked with appropriate legends. Each option to purchase shares of Korro Bio common stock outstanding as of immediately prior to the Effective Time shall automatically be converted, at the Effective Time, into an option to acquire, on the same terms and conditions (including the same vesting and exercisability terms and conditions), the number of shares of Frequency common stock equal to the number of shares of Korro Bio common stock subject to such option as of immediately prior to the Effective Time multiplied by the exchange ratio formula in the Merger Agreement and rounding that result down to the nearest whole number of shares, as described in more detail in the sections titled “The Merger Agreement—Treatment of Korro Bio Warrants” and “The Merger Agreement—Treatment of Korro Bio Options” beginning on page 194 of this proxy statement/prospectus.

Each outstanding Frequency Option will remain outstanding and such options, subject to proportionate adjustment in accordance with the terms of Frequency’s 2019 Incentive Award Plan or 2014 Stock Incentive Plan, as applicable, to reflect the Reverse Stock Split and the issuance of the CVRs, will be unaffected by the Merger, provided that each such Frequency Option that is unvested will vest in full immediately prior to the Effective Time. Each restricted stock unit award covering shares of Frequency common stock that is outstanding will remain outstanding and such restricted stock unit awards, subject to proportionate adjustment in accordance with the terms of Frequency’s 2019 Incentive Award Plan to reflect the Reverse Stock Split and issuance of the CVRs, will be unaffected by the Merger, provided that each restricted stock unit award that vests solely based on the holder’s continued employment or service will vest in full immediately prior to the Effective Time.

Q:    Why are the two companies proposing to combine?

A: Frequency and Korro Bio believe that combining the two companies will result in a company with a robust pipeline, strong leadership team and substantial capital resources, positioning it to become a leading company researching, developing and commercializing therapies for diseases. For a more complete description of the

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reasons for the Merger, please see the sections titled “The Merger—Frequency Reasons for the Merger” and “The Merger—Korro Bio Reasons for the Merger” beginning on pages 165 and 169, respectively, of this proxy statement/prospectus.

Q:    What will Korro Bio stockholders and optionholders receive in the Merger?

A: Korro Bio stockholders will receive shares of Frequency common stock, and Korro Bio optionholders will receive options to purchase Frequency common stock. The Korro Bio securityholders as of immediately before the Merger (including purchasers in the Pre-Closing Financing) are expected to own approximately 92% of the aggregate number of shares of the combined company’s common stock on a fully-diluted basis, and Frequency securityholders immediately before the Merger are expected to own approximately 8% of the aggregate number of shares of the combined company common stock on a fully-diluted basis, in each case subject to certain assumptions, including, but not limited to, Frequency’s net cash as of closing being equal to $25 million. If any Korro Bio common stock outstanding immediately prior to the Effective Time is unvested or is subject to a repurchase option or a risk of forfeiture under any applicable agreement with Korro Bio, then the shares of Frequency common stock issued in exchange for such shares of Korro Bio common stock will to the same extent be unvested and subject to the same repurchase option or risk of forfeiture, and such shares of Frequency common stock will be marked with appropriate legends.

In connection with the Merger, each option to purchase shares of Korro Bio common stock outstanding as of immediately prior to the Effective Time shall automatically be converted, at the Effective Time, into an option to acquire, on the same terms and conditions (including the same vesting and exercisability terms and conditions), the number of shares of Frequency common stock equal to the number of shares of Korro Bio common stock subject to such option as of immediately prior to the Effective Time multiplied by the exchange ratio formula in the Merger Agreement and rounding that result down to the nearest whole number of shares, and will be eligible to be registered on Form S-8.

For a more complete description of what Korro Bio stockholders and optionholders will receive in the Merger, please see the sections titled “The Merger Agreement—Merger Consideration,” “The Merger Agreement—Treatment of Korro Bio Warrants” and “The Merger Agreement—Treatment of Korro Bio Options” beginning on pages 190, and 194, respectively, of this proxy statement/prospectus.

Q:    Will the common stock of the combined company trade on an exchange?

A: Shares of Frequency common stock are currently listed on The Nasdaq Global Select Market, or Nasdaq, under the symbol “FREQ.” Frequency intends to file an initial listing application for the combined company with the Nasdaq Stock Market LLC. After completion of the Merger, Frequency will be renamed “Korro Bio, Inc.” and it is expected that the common stock of the combined company will trade on Nasdaq under the symbol “KRRO.”

Q:    Who will be the directors of the combined company following the Merger?

A: Immediately following the Merger, the combined company’s board of directors will be composed of seven members, consisting of (i) four current Korro Bio board members, namely Ram Aiyar,             ,             , and             , (ii) two members to be determined by mutual agreement of the Frequency board designee and the Korro Bio board designees, namely              and             , each of whom shall meet Nasdaq’s independence requirements, and (iii) one current Frequency board member, namely David L. Lucchino. The staggered structure of the Frequency board of directors will remain in place for the combined company following the completion of the Merger. The Frequency board of directors has determined that each of the directors other than Ram Aiyar and David L. Lucchino meet the Nasdaq independence requirements.

It is anticipated the director classes of the combined company board of directors will be as follows:

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Q:    Who will be the executive officers of the combined company immediately following the Merger?

A: Immediately following the Merger, the executive management team of the combined company is expected to consist of members of the Korro Bio executive management team prior to the Merger, including:

Q:    When do you expect the Merger to be consummated?

A: The Merger is anticipated to close in the fourth quarter of 2023, but the exact timing cannot be predicted. For more information, please see the section titled “The Merger Agreement—Conditions to the Completion of the Merger” beginning on page 207 of this proxy statement/prospectus.

Q:    As a Frequency stockholder, how does Frequency’s board of directors recommend that I vote?

A: After careful consideration, Frequency’s board of directors unanimously recommends that Frequency stockholders vote “FOR” the director nominee and “FOR” all of the proposals.

Q:    What risks should I consider in deciding whether to vote in favor of the Merger?

A: You should carefully review the section titled “Risk Factors” beginning on page 32 of this proxy statement/prospectus, which set forth certain risks and uncertainties related to the Merger, risks and uncertainties to which the combined company’s business will be subject, and risks and uncertainties to which each of Frequency and Korro Bio, as independent companies, are subject.

Q:    What are the CVRs being issued to Frequency stockholders?

A: Prior to the Effective Time, unless (i) the disposition of any of Frequency’s assets related to its multiple sclerosis program, or the MS Asset Disposition, has been consummated prior to or on the closing date of the Merger and (ii) all proceeds from the MS Asset Disposition are taken into account in the final Frequency Net Cash and there are no contingent payments, licenses, fees or royalties, equity securities or other non-cash assets or rights that may be payable by any acquiror of any of Frequency’s assets related to its multiple sclerosis program, or MS Assets, or otherwise as a result of the MS Asset Disposition after the closing of the Merger, Frequency and Computershare Trust Company, N.A. and Computershare Inc., collectively as the Rights Agent, as rights agent, will enter into a Contingent Value Rights Agreement, or the CVR Agreement, pursuant to which Frequency stockholders of record as of the close of business on the last business day prior to the day on which the Effective Time occurs will receive one CVR for each outstanding share of Frequency common stock held by such stockholder on such date. A copy of the form of CVR Agreement is included as Annex E to this proxy statement/prospectus.

The CVRs represent the contractual right to receive payments from Frequency upon the actual receipt by Frequency or its subsidiaries of cash consideration that is paid to or received by Frequency or its subsidiaries as a result of any MS Asset Disposition or revenue received from the license of its MS Assets, or as a result of Frequency’s equity ownership in any subsidiary that is established to hold such assets or the subsequent disposition of any such equity securities, or, collectively, the CVR Milestones, net of certain income taxes required to be paid in cash, transaction costs and certain other expenses.

The contingent payments under the CVR Agreement, if they become payable, will become payable to the Rights Agent for subsequent distribution to the holders of the CVRs. In the event that no CVR Milestones occur, holders

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of the CVRs will not receive any payment pursuant to the CVR Agreement. There can be no assurance that any CVR Milestones will be achieved or that any holders of CVRs will receive payments with respect thereto.

The right to the contingent payments contemplated by the CVR Agreement is a contractual right only and will not be transferable, except in the limited circumstances specified in the CVR Agreement. The CVRs will not be evidenced by a certificate or any other instrument and will not be registered with the SEC. The CVRs will not have any voting or dividend rights and will not represent any equity or ownership interest in Frequency or the combined company or any of its subsidiaries. No interest will accrue on any amounts payable in respect of the CVRs.

For a more detailed description of the CVRs and the CVR Agreement, see “Agreements Related to the Merger—Contingent Value Rights Agreement” beginning on page 214 of this proxy statement/prospectus.

Q:    What are the material U.S. federal income tax consequences of the issuance of the CVRs and of the receipt of payments on the CVRs (if any) to holders of Frequency common stock?

A: The U.S. federal income tax treatment of the CVRs and payments (if any) thereon is uncertain. Except to the extent otherwise required pursuant to a change in applicable law after the date of the CVR Agreement, neither Frequency nor the Rights Agent will report the issuance of the CVRs as a current distribution and will report each payment (if any) on the CVRs as a distribution by Frequency for U.S. federal income tax purposes. This position may be challenged by the Internal Revenue Service, or the IRS, in which case holders of Frequency common stock could be required to recognize taxable income in respect of the issuance of the CVRs without a corresponding receipt of cash. See the section titled “Agreements Related to the Merger—Contingent Value Rights Agreement—Material U.S. Federal Income Tax Consequences of the CVRs to Holders of Frequency Common Stock” beginning on page 218 for a discussion of the material U.S. federal income tax consequences of the issuance of the CVRs and the receipt of payments (if any) thereon to holders of Frequency common stock.

Q:    What are the material U.S. federal income tax consequences of the Merger to holders of Korro Bio common stock?

A: Frequency and Korro Bio intend the Merger to qualify as a “reorganization” within the meaning of Section 368(a) of the Internal Revenue Code of 1986, as amended, or the Code. Assuming the Merger qualifies as a “reorganization” within the meaning of Section 368(a) of the Code, subject to the limitations and qualifications described in the section titled “Material U.S. Federal Income Tax Consequences of the Merger” beginning on page 223, holders of Korro Bio common stock that exchange their Korro Bio stock for Frequency common stock in the Merger generally should not recognize gain or loss for U.S. federal income tax purposes on such exchange. However, if the Merger does not qualify as a “reorganization” within the meaning of Section 368(a) of the Code, the Merger would be a taxable transaction to U.S. Holders (as defined in the section titled “Material U.S. Federal Income Tax Consequences of the Merger”), but Non-U.S. Holders (as defined in the section titled “Material U.S. Federal Income Tax Consequences of the Merger”) generally would not be subject to U.S. federal income tax on any gain realized in connection with the Merger.

The closing of the Merger is not conditioned upon the receipt of an opinion of counsel or a ruling from the IRS regarding the U.S. federal income tax treatment of the Merger, and no opinion of counsel or ruling from the IRS will be requested regarding such treatment. Accordingly, there can be no assurance that the IRS will not challenge the qualification of the Merger as a “reorganization” within the meaning of Section 368(a) of the Code or that a court will not sustain such a challenge by the IRS.

The tax consequences to you of the Merger will depend on your particular facts and circumstances. Please consult your tax advisor as to the tax consequences of the Merger in your particular circumstances, including the applicability and effect of U.S. federal, state, local and foreign income and other tax laws. For a more detailed discussion of the material U.S. federal income tax consequences of the Merger, see “Material U.S. Federal Income Tax Consequences of the Merger” beginning on page 223.

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Questions and Answers About the Frequency Annual Meeting and Voting

Q:    Who is entitled to vote at the Frequency Annual Meeting?

A: Holders of record of shares of Frequency common stock as of the close of business on     , 2023, or the Record Date, are entitled to notice of and to vote at the Frequency Annual Meeting and any continuation, postponement or adjournment thereof. At the close of business on the Record Date, there were                     shares of Frequency common stock issued and outstanding and entitled to vote. Each share of Frequency common stock is entitled to one vote on any matter presented to stockholders at the Frequency Annual Meeting.

Q:    How do I attend the Frequency Annual Meeting?

A: The Frequency Annual Meeting will be held on      , 2023 at      a.m.      Eastern Time via a live webcast. Prior registration at www.proxydocs.com/FREQ to attend the Frequency Annual Meeting is required by      a.m. Eastern Time on      ,     2023, or the Registration Deadline. You will need the control number that appears on your proxy card, or the Control Number, to register to attend the meeting. If your shares are held in “street name”, you should use your Control Number provided on your notice or voting instruction form, or otherwise vote through the bank, broker or other nominee. The meeting webcast will begin promptly at a.m. Eastern Time. We encourage you to access the meeting prior to the start time. We will have technicians ready to assist you with any technical difficulties you may have accessing the virtual meeting website by calling the technical support number provided by email one hour prior to the Frequency Annual Meeting. After completion of your registration by the Registration Deadline, further instructions, including a unique link to access the Frequency Annual Meeting, will be emailed to you. For any questions on how to register for the Frequency Annual Meeting, please contact our General Counsel, James P. Abely, at (781) 315-4623 or jabely@frequencytx.com.

Q:    What proposals will be voted on at the Frequency Annual Meeting in connection with the Merger?

A: Pursuant to the terms of the Merger Agreement, Proposal No. 1 to approve the issuance of shares of common stock of Frequency to stockholders of Korro Bio, pursuant to the terms of the Merger Agreement and the change of control resulting from the Merger must be approved by the requisite stockholder vote at the Frequency Annual Meeting in order for the Merger to close. Proposal No. 1 is referred to in this proxy statement/prospectus as the Merger Proposal. Approval of the Merger Proposal is a condition to completion of the Merger. Therefore, the Merger cannot be consummated without the approval of the Merger Proposal and Proposal No. 2.

In addition, each of the other closing conditions set forth in the Merger Agreement must be satisfied or waived for the Merger to close. For a more complete description of the closing conditions under the Merger Agreement, please see the section titled “The Merger Agreement—Conditions to the Completion of the Merger” beginning on page 207 of this proxy statement/prospectus.

Q:    What proposals are to be voted on at the Frequency Annual Meeting, other than in connection with the Merger?

A: At the Frequency Annual Meeting, the holders of Frequency common stock will also be asked to consider the following proposals:

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The approval of Proposal Nos. 3, 4, 5, 6 and 7. are not a condition to the Merger closing.

Q:    What are the material U.S. federal income tax consequences of the proposed Reverse Stock Split to U.S. Holders of Frequency common stock?

A: A U.S. Holder (as defined in the section titled “Matters Being Submitted to a Vote of Frequency Stockholders—Proposal No. 2: Approval of the Amendment to the Restated Certificate of Incorporation of Frequency Effecting the Reverse Stock Split—Material U.S. Federal Income Tax Consequences of the Reverse Stock Split to U.S. Holders of Frequency Common Stock” beginning on page 242) of Frequency common stock generally should not recognize gain or loss upon the proposed Reverse Stock Split, except to the extent such holder receives cash in lieu of a fractional share of Frequency common stock, and subject to the discussion in the section titled “Matters Being Submitted to a Vote of Frequency Stockholders—Proposal No. 2: Approval of the Amendment to the Restated Certificate of Incorporation of Frequency Effecting the Reverse Stock Split—Material U.S. Federal Income Tax Consequences of the Reverse Stock Split to U.S. Holders of Frequency Common Stock” beginning on page 242, which provides a more complete description of the material U.S. federal income tax consequences of the Reverse Stock Split to U.S. Holders of Frequency common stock, including possible alternative treatments.

Q:    As a Frequency stockholder, how does Frequency’s board of directors recommend that I vote?

A: After careful consideration, Frequency’s board of directors unanimously recommends that Frequency stockholders vote “FOR” the director nominee and “FOR” all of the proposals.

Q:    How do I vote my shares?

A: We recommend that stockholders vote by proxy even if they plan to attend the Frequency Annual Meeting and vote electronically. If you are a stockholder of record, there are three ways to vote by proxy:

Telephone and Internet voting facilities for stockholders of record will be available 24 hours a day and will close at 11:59 p.m. Eastern Time on             , 2023.

If your shares are held in “street name” by a bank, broker or other nominee, you will receive instructions on how to vote from the bank, broker or other nominee. You must follow the instructions of such bank, broker or other nominee in order for your shares to be voted.

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Q:    How can I vote my shares at the Frequency Annual Meeting?

A: If you have registered to attend the Frequency Annual Meeting, you may vote at the Frequency Annual Meeting through www.proxydocs.com/FREQ. To be admitted to the Frequency Annual Meeting and vote your shares, you must register by the Registration Deadline and provide the Control Number. Even if you plan to attend the Frequency Annual Meeting, we encourage you to vote in advance by Internet, telephone or mail so that your vote will be counted even if you later decide not to attend the Frequency Annual Meeting.

Q:    What is the difference between being a “record holder” and holding shares in “street name”?

A: A record holder (also called a “registered holder”) holds shares in his or her name. Shares held in “street name” means that shares are held in the name of a bank, broker or other nominee on the holder’s behalf.

Q:    What do I do if my shares are held in “street name”?

A: If your shares are held in a brokerage account or by a bank or other holder of record, you are considered the “beneficial owner” of shares held in “street name.” This proxy statement/prospectus has been forwarded to you by your broker, bank or other nominee who is considered, with respect to those shares, the stockholder of record. As the beneficial owner, you have the right to direct your broker, bank or nominee on how to vote your shares by following their instructions for voting. Please refer to the information from your bank, broker or other nominee on how to submit your voting instructions. In addition, if you are a “street name” stockholder, you are invited to attend and vote your shares at the Frequency Annual Meeting live via webcast so long as you register to attend the Frequency Annual Meeting at www.proxydocs.com/FREQ by the Registration Deadline and have requested a legal proxy from your broker, bank, or nominee.

Q:    What are broker non-votes?

A: A “broker non-vote” occurs when shares held by a broker in “street name” for a beneficial owner are not voted with respect to a proposal because (1) the broker has not received voting instructions from the stockholder who beneficially owns the shares and (2) the broker lacks the authority to vote the shares at their discretion.

Under current NYSE interpretations that govern broker non-votes, the Merger Proposal, Proposal No. 3 for the election of directors, Proposal No. 5 to approve the 2023 Stock Option and Incentive Plan, Proposal No. 6 to approve the 2023 Employee Stock Purchase Plan and Proposal No. 7 to adjourn the meeting to seek additional proxies are considered a non-discretionary matter, and a broker does not have the authority to vote uninstructed shares at its discretion on such proposals. Proposal No. 2 to amend Frequency’s Restated Certificate of Incorporation to effect a reverse stock split of Frequency common stock and Proposal No. 4 for the ratification of the appointment of RSM US LLP as Frequency’s independent registered public accounting firm are considered discretionary matters, and a broker is permitted to exercise its discretion to vote uninstructed shares on the proposal.

Q:    How many shares must be present to hold the Frequency Annual Meeting?

A: A quorum must be present at the Frequency Annual Meeting for any business to be conducted. The holders of a majority in voting power of Frequency capital stock issued and outstanding and entitled to vote, present by remote communication or represented by proxy, constitutes a quorum. If you sign and return your paper proxy card or authorize a proxy to vote electronically or telephonically, your shares will be counted to determine whether there is a quorum even if you abstain or fail to vote.

Broker non-votes will also be considered present for the purpose of determining whether there is a quorum for the Frequency Annual Meeting.

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Q:    What if a quorum is not present at the Frequency Annual Meeting?

A: If a quorum is not present or represented at the scheduled time of the Frequency Annual Meeting, (i) the chairperson of the Frequency Annual Meeting or (ii) a majority in voting power of the stockholders entitled to vote at the Frequency Annual Meeting, present by remote communication or represented by proxy, may adjourn the Frequency Annual Meeting until a quorum is present or represented.

Q:    How many votes are required to approve each proposal?

A: The table below summarizes the proposals that will be voted on, the vote required to approve each item and how votes are counted:

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The directors and certain executive officers of Frequency have entered into stockholder support agreements pursuant to which they have agreed to vote all shares of Frequency common stock owned by them as of the Record Date in favor of Proposal Nos. 1 and 2 and against any competing “acquisition proposal” (as defined in the support agreements). As of the Record Date, the directors and certain executive officers of Frequency owned or controlled     % of the outstanding shares of Frequency common stock entitled to vote at the Frequency Annual Meeting.

Q:    What happens if I do not vote or submit a proxy but do not provide voting instructions?

A: Failure to vote will have the same effect as a vote “AGAINST” Proposal No. 2 and no effect on Proposal Nos. 1, 3, 4, 5, 6 and 7. If you submit a proxy but do not provide any voting instructions, the persons named as proxies will vote in accordance with the recommendations of the Frequency board of directors. The Frequency board of director’s recommendations are set forth above, as well as with the description of each proposal in this proxy statement/prospectus.

Q:    Can I revoke or change my vote after I submit my proxy?

A: Yes. Whether you have voted by Internet, telephone or mail, if you are a stockholder of record, you may change your vote and revoke your proxy by:

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If you hold shares in “street name”, you may submit new voting instructions by contacting your bank, broker or other nominee. If you are a “street name” stockholder, you are invited to attend and vote your shares at the Frequency Annual Meeting live via webcast so long as you register to attend the Frequency Annual Meeting at www.proxydocs.com/FREQ by the Registration Deadline.

Your most recent proxy card or telephone or Internet proxy is the one that is counted. Your attendance at the Frequency Annual Meeting by itself will not revoke your proxy unless you give written notice of revocation to Frequency before your proxy is voted or you vote electronically at the Frequency Annual Meeting.

Q:    Who counts the votes?

A: A representative of Mediant Communications Inc. has been engaged as Frequency’s independent agent to tabulate stockholder votes.

Q:    Who is paying for this proxy solicitation?

A: Frequency will pay the cost of printing and filing of this proxy statement/prospectus and the proxy card. Arrangements will also be made with brokerage firms and other custodians, nominees and fiduciaries who are record holders of Frequency common stock for the forwarding of solicitation materials to the beneficial owners of Frequency common stock. Frequency will reimburse these brokers, custodians, nominees and fiduciaries for the reasonable out-of-pocket expenses they incur in connection with the forwarding of solicitation materials. Frequency has retained Morrow Sodali LLC, or Morrow Sodali, to assist it in soliciting proxies. Frequency will pay the fees of Morrow Sodali, which Frequency expects to be approximately $            , plus reimbursement of out-of-pocket expenses.

Q:     How can I find out the results of the voting at the Frequency Annual Meeting?

A: Preliminary voting results will be announced at the Frequency Annual Meeting. Final voting results will be published in a Current Report on Form 8-K, or Form 8-K, that Frequency will file with the SEC within four business days after the Frequency Annual Meeting. If final voting results are not available in time to file a Form 8-K within four business days after the Frequency Annual Meeting, Frequency intends to file a Form 8-K to publish preliminary results and, within four business days after the final results are known, file an additional Form 8-K to publish the final results.

Q:    What does it mean if I receive more than one set of proxy materials?

A: It means that your shares are held in more than one account at the transfer agent and/or with banks, brokers or other nominees in “street name” as described below. Please vote all of your shares. To ensure that all of your shares are voted, for each set of proxy materials, please submit your proxy by phone, via the Internet, or, if you received printed copies of the proxy materials, by signing, dating and returning the enclosed proxy card in the enclosed envelope.

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Q:    Who can help answer my questions?

A: If you are a Frequency stockholder and would like additional copies of this proxy statement/prospectus without charge or if you have questions about the Frequency Annual Meeting, including the procedures for voting your shares, you should contact:

Frequency Therapeutics, Inc.

75 Hayden Avenue, Suite 300

Lexington, Massachusetts 02421

Telephone: Tel: (781) 315-4600

Attn: James Abely

If your shares are held in street name, please contact the your bank, broker or other nominee.

To ensure timely delivery of documents prior to the Frequency Annual Meeting, any requests must be made no later than             , 2023.

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MARKET PRICE AND DIVIDEND INFORMATION

The closing price of Frequency common stock on July 13, 2023, the last trading day prior to the public announcement of the Merger, was $0.40 per share, as reported on Nasdaq. The closing price of the Frequency common stock on July 26, 2023, the last practicable date before the date of this proxy statement/prospectus, as reported on Nasdaq, was $0.54 per share.

Because the market price of Frequency common stock is subject to fluctuation, the market value of the shares of Frequency common stock that Korro Bio stockholders will be entitled to receive in the Merger may increase or decrease.

Korro Bio is a private company, and its shares of common stock and preferred stock are not publicly traded.

Assuming approval of Proposal Nos. 1 and 2 and successful application for initial listing with Nasdaq, following the consummation of the Merger, the Frequency common stock will trade on Nasdaq under Frequency’s new name, “Korro Bio, Inc.,” and new trading symbol “KRRO.”

As of             , 2023, the Record Date for the Annual meeting, there were approximately                      registered holders of record of the Frequency common stock. As of             , 2023, Korro Bio had                      holders of record of Korro Bio common stock and                      holders of record of Korro Bio preferred stock. For detailed information regarding the beneficial ownership of certain Frequency and Korro Bio stockholders, see the sections of this proxy statement/prospectus titled “Principal Stockholders of Frequency” and “Principal Stockholders of Korro Bio” beginning on pages 418 and 420, respectively.

Dividends

Frequency has never declared or paid cash dividends on its capital stock. Korro Bio has never paid or declared any cash dividends on its capital stock. Korro Bio intends to retain all available funds and any future earnings for use in the operation of its business and does not anticipate paying any cash dividends on its capital stock in the foreseeable future. Notwithstanding the foregoing, any determination to pay cash dividends subsequent to the Merger will be at the discretion of the combined company’s board of directors and will depend upon a number of factors, including the combined company’s results of operations, financial condition, future prospects, contractual restrictions, restrictions imposed by applicable law and other factors the combined company’s board of directors deems relevant.

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RISK FACTORS

The combined company will be faced with a market environment that cannot be predicted and that involves significant risks, many of which will be beyond its control. In addition to the other information contained in this proxy statement/prospectus, you should carefully consider the material risks described below before deciding how to vote your shares of Frequency common stock. You should also read and consider the other information in this proxy statement/prospectus.

Risks Related to the Merger

The exchange ratio will not be adjusted based on the market price of Frequency common stock so the merger consideration at the closing may have a greater or lesser value than at the time the Merger Agreement was signed.

At the Effective Time, outstanding shares of Korro Bio common stock will be converted into shares of Frequency common stock. The former Korro Bio securityholders, including purchasers in the Pre-Closing Financing, immediately before the Merger are expected to own approximately 92% of the aggregate number of shares of Frequency common stock following the Merger on a fully-diluted basis, and Frequency securityholders immediately before the Merger are expected to own approximately 8% of the aggregate number of shares of Frequency common stock following the Merger on a fully-diluted basis, subject to certain assumptions, including, but not limited to, (a) a valuation of Frequency equal to its net cash as of the business day immediately prior to the closing date of the Merger, plus $15.0 million, (b) a valuation for Korro Bio equal to $325.6 million and (c) Korro Bio issuing approximately $117.3 million of Korro Bio common stock in the Pre-Closing Financing described elsewhere in this proxy statement/prospectus.

Any changes in the market price of Frequency common stock before the completion of the Merger will not affect the number of shares Korro Bio stockholders will be entitled to receive pursuant to the Merger Agreement. Therefore, if before the completion of the Merger, the market price of Frequency common stock increases from the market price on the date of the Merger Agreement, then Korro Bio stockholders could receive merger consideration with substantially more value for their shares of Korro Bio common stock than the parties had negotiated when they established the exchange ratio. Similarly, if before the completion of the Merger the market price of Frequency common stock declines from the market price on the date of the Merger Agreement, then Korro Bio stockholders could receive merger consideration with substantially lower value. The Merger Agreement does not include a price-based termination right.

Failure to complete the Merger may result in Frequency paying a termination fee to Korro Bio, which could harm the Frequency common stock price and future business and operations of Frequency.

If the Merger is not completed, Frequency is subject to the following risks:

If the Merger Agreement is terminated and the board of directors of Frequency determines to seek another business combination, there can be no assurance that Frequency will be able to find a partner with whom a business combination would yield greater benefits than the benefits to be provided under the Merger Agreement.

If the conditions to the Merger are not satisfied or waived, the Merger may not occur.

Even if the Merger is approved by the stockholders of Korro Bio and the Merger Proposal is approved by the Frequency stockholders, specified conditions must be satisfied or waived to complete the Merger. These

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conditions are set forth in the Merger Agreement and described in the section titled “The Merger Agreement—Conditions to the Completion of the Merger” beginning on page 207 of this proxy statement/prospectus. Among other things, the Merger Agreement requires the existing shares of Frequency common stock to be continually listed with the Nasdaq Stock Market LLC through the Effective Time. The listing of Frequency common stock with the Nasdaq Stock Market LLC will depend on many factors, including those discussed in the risk factor entitled “Frequency’s failure to meet the continued listing requirements of the Nasdaq Stock Market LLC could result in a delisting of its common stock.” Frequency and Korro Bio cannot assure you that all of the conditions to the consummation of the Merger will be satisfied or waived. If the conditions are not satisfied or waived, the Merger may not occur or the closing may be delayed, and Frequency and Korro Bio each may lose some or all of the intended benefits of the Merger.

The Merger may be completed even though a material adverse effect may result from the announcement of the Merger, industry-wide changes or other causes.

In general, neither Frequency nor Korro Bio is obligated to complete the Merger if there is a material adverse effect affecting the other party between July 14, 2023, the date of the Merger Agreement, and the closing of the Merger. However, certain types of changes are excluded from the concept of a “material adverse effect.” Such exclusions include but are not limited to changes in general economic or political conditions, industry wide changes, changes resulting from the announcement of the Merger, natural disasters, pandemics, other public health events and changes in GAAP. Therefore, if any of these events were to occur impacting Frequency or Korro Bio, the other party would still be obliged to consummate the closing of the Merger. If any such adverse changes occur and Frequency and Korro Bio consummate the closing of the Merger, the stock price of the combined company may suffer. This in turn may reduce the value of the Merger to the stockholders of Frequency, Korro Bio or both. For a more complete discussion of what constitutes a material adverse effect on Frequency or Korro Bio, see the section titled “The Merger Agreement—Representations and Warranties” beginning on page 197 of this proxy statement/prospectus.

If Frequency and Korro Bio complete the Merger, the combined company will need to raise additional capital by issuing equity securities or additional debt or through licensing arrangements, which may cause significant dilution to the combined company’s stockholders or restrict the combined company’s operations.

Additional financing may not be available to the combined company when it is needed or may not be available on favorable terms. To the extent that the combined company raises additional capital by issuing equity securities, such financing will cause additional dilution to all securityholders of the combined company, including Frequency’s pre-Merger stockholders and Korro Bio’s former securityholders. It is also possible that the terms of any new equity securities may have preferences over the combined company’s common stock. Any debt financing the combined company enters into may involve covenants that restrict its operations. These restrictive covenants may include limitations on additional borrowing and specific restrictions on the use of the combined company’s assets, as well as prohibitions on its ability to create liens, pay dividends, redeem its stock or make investments. In addition, if the combined company raises additional funds through licensing arrangements, it may be necessary to grant licenses on terms that are not favorable to the combined company.

Some Frequency and Korro Bio directors and executive officers have interests in the Merger that are different from yours and that may influence them to support or approve the Merger without regard to your interests.

Directors and executive officers of Frequency and Korro Bio may have interests in the Merger that are different from, or in addition to, the interests of other Frequency stockholders generally. These interests with respect to Frequency’s directors and executive officers may include, among others, acceleration of Frequency Options, Frequency restricted stock units, retention bonus payments, severance payments and benefits if employment is terminated in a qualifying termination in connection with the Merger and rights to continued indemnification, expense advancement and insurance coverage. David L. Lucchino, a current member of the Frequency board of directors will continue as a director of the combined company after the Effective Time.

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Following the Effective Time, it is expected that the combined company will provide compensation to non-employee directors pursuant to a new non-employee director compensation policy that is expected to be adopted post-closing. These interests with respect to Korro Bio’s directors and executive officers may include, among others, certain of Korro Bio’s directors and executive officers have options, subject to vesting, to purchase shares of Korro Bio common stock which, after the Effective Time, will be converted into and become options to purchase shares of the common stock of the combined company; Korro Bio’s executive officers are expected to continue as executive officers of the combined company after the Effective Time; and all of Korro Bio’s directors and executive officers are entitled to certain indemnification and liability insurance coverage pursuant to the terms of the Merger Agreement. Further, certain current members of Korro Bio’s board of directors will continue as directors of the combined company after the Effective Time, and, following the Effective Time, it is expected that the combined company will provide compensation to non-employee directors pursuant to a new non-employee director compensation policy that is expected to be adopted post-closing.

The board of directors of both Frequency and Korro Bio were aware of and considered these interests, among other matters, in reaching their decisions to approve and adopt the Merger Agreement, approve the Merger, approve the issuance of Frequency common stock in the Merger, and recommend the approval of the Merger Agreement to Korro Bio stockholders and the issuance of the Frequency common stock to Korro Bio stockholders in the Merger to the Frequency stockholders. These interests, among other factors, may have influenced the directors and executive officers of Frequency and Korro Bio to support or approve the Merger.

For more information regarding the interests of Frequency and Korro Bio directors and executive officers in the Merger, please see the sections titled “The Merger—Interests of Frequency Directors and Executive Officers in the Merger” beginning on page 178 and “The Merger—Interests of Korro Bio Directors and Executive Officers in the Merger” beginning on page 183 of this proxy statement/prospectus.

Frequency stockholders may not realize a benefit from the Merger commensurate with the ownership dilution they will experience in connection with the Merger.

If the combined company is unable to realize the full strategic and financial benefits currently anticipated from the Merger, Frequency stockholders will have experienced substantial dilution of their ownership interests without receiving any commensurate benefit, or only receiving part of the commensurate benefit to the extent the combined company is able to realize only part of the strategic and financial benefits currently anticipated from the Merger.

If the Merger is not completed, Frequency’s stock price may decline significantly.

The market price of Frequency common stock is subject to significant fluctuations. During the 12-month period ended June 30, 2023, the closing sales price of Frequency common stock on Nasdaq ranged from a high of $5.4750 on January 24, 2023 to a low of $0.3318 on June 21, 2023. Market prices for securities of pharmaceutical, biotechnology and other life science companies have historically been particularly volatile. In addition, the market price of Frequency common stock will likely be volatile based on whether stockholders and other investors believe that Frequency can complete the Merger or otherwise raise additional capital to support Frequency’s operations if the Merger is not consummated and another strategic transaction cannot be identified, negotiated and consummated in a timely manner, if at all. The volatility of the market price of Frequency common stock is exacerbated by low trading volume. Additional factors that may cause the market price of Frequency common stock to fluctuate include:

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See also “Risks related to Frequency common stock—The market price of Frequency common stock has been volatile and fluctuated and may in future fluctuate substantially, which could result in substantial losses for Frequency’s stockholders”. Moreover, the stock markets in general have experienced substantial volatility that has often been unrelated to the operating performance of individual companies. These broad market fluctuations may also adversely affect the trading price of Frequency common stock. In the past, following periods of volatility in the market price of a company’s securities, stockholders have often instituted class action securities litigation against such companies.

Frequency and Korro Bio securityholders will have a reduced ownership and voting interest in, and will exercise less influence over the management of, the combined company following the completion of the Merger as compared to their current ownership and voting interests in the respective companies.

After the completion of the Merger, the current stockholders of Frequency and Korro Bio will own a smaller percentage of the combined company than their ownership of their respective companies prior to the Merger. Immediately after the Merger, Frequency securityholders as of immediately prior to the Merger are expected to own approximately 8% of the outstanding shares of the combined company on a fully-diluted basis and former Korro Bio securityholders, including purchasers in the Pre-Closing Financing, are expected to own approximately 92% of the outstanding shares of the combined company on a fully-diluted basis, subject to certain assumptions, including, but not limited to, (a) a valuation of Frequency equal to its net cash as of the business day immediately prior to the closing date of the Merger, plus $15.0 million, (b) a valuation for Korro Bio equal to $325.6 million and (c) Korro Bio issuing approximately $117.3 million of Korro Bio common stock in the Pre-Closing Financing described elsewhere in this proxy statement/prospectus.

During the pendency of the Merger, Frequency and Korro Bio may not be able to enter into a business combination with another party on more favorable terms because of restrictions in the Merger Agreement, which could adversely affect their respective business prospects.

Covenants in the Merger Agreement impede the ability of Frequency and Korro Bio to make acquisitions during the pendency of the Merger, subject to specified exceptions. As a result, if the Merger is not completed, the parties may be at a disadvantage to their competitors during that period. In addition, while the Merger Agreement is in effect, each party is generally prohibited from soliciting, proposing, seeking or knowingly encouraging, facilitating or supporting any inquiries, indications of interest, proposals or offers that constitute or may reasonably be expected to lead to certain transactions involving a third party, including a merger, sale of assets or other business combination, subject to specified exceptions. Any such transactions could be favorable to such party’s stockholders, but the parties may be unable to pursue them. For more information, see the sections titled “The Merger Agreement—Non-Solicitation” beginning on page 201.

Certain provisions of the Merger Agreement may discourage third parties from submitting competing proposals, including proposals that may be superior to the transactions contemplated by the Merger Agreement.

The terms of the Merger Agreement prohibit each of Frequency and Korro Bio from soliciting competing proposals or cooperating with persons making unsolicited takeover proposals, except in limited circumstances as described in further detail in the section titled “The Merger Agreement—Non-Solicitation” beginning on page 201. In addition, if Frequency terminates the Merger Agreement under specified circumstances, Frequency would be required to pay Korro Bio a termination fee of $1.5 million. This termination fee may discourage third parties from submitting competing proposals to Frequency or its stockholders, and may cause the Frequency board of directors to be less inclined to recommend a competing proposal.

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Because the lack of a public market for Korro Bio’s stock makes it difficult to evaluate the fair market value of Korro Bio’s stock, Frequency may pay more than the fair market value of Korro Bio’s stock and/or the stockholders of Korro Bio may receive consideration in the Merger that is less than the fair market value of Korro Bio’s stock.

The outstanding Korro Bio common stock is privately held and is not traded in any public market. The lack of a public market makes it difficult to determine the fair market value of Korro Bio’s stock. Because the percentage of Frequency equity to be issued to Korro Bio stockholders was determined based on negotiations between the parties, it is possible that the value of the Frequency common stock to be received by Korro Bio stockholders will be less than the fair market value of Korro Bio’s stock, or Frequency may pay more than the aggregate fair market value for Korro Bio’s stock.

Frequency stockholders may not receive any payment on the CVRs, and the CVRs may expire valueless.

The right of Frequency stockholders to receive any future payment on or derive any value from the CVRs will be contingent solely upon the occurrence of the CVR Milestones within the time periods specified in the CVR Agreement and the consideration received being greater than the amounts permitted to be withheld or deducted by Frequency under the CVR Agreement. There is no guarantee that Frequency will be able to successfully collaborate or sell any of these assets or establish a viable entity to manage the development of these assets. In the event that no CVR Milestones occur within the time periods specified in the CVR Agreement, no payments will be made under the CVR Agreement, and the CVRs will expire valueless.

Furthermore, the CVRs will be unsecured obligations of the combined company and all payments under the CVRs, all other obligations under the CVR Agreement and the CVRs and any rights or claims relating thereto may be subordinated in right of payment to the prior payment in full of all current or future senior obligations of the combined company.

The tax treatment of the CVRs is unclear.

The U.S. federal income tax treatment of the CVRs is unclear. There is no legal authority directly addressing the U.S. federal income tax treatment of the receipt of, and payments under, the CVRs, and there can be no assurance that the IRS would not assert, or that a court would not sustain, a position that could result in adverse U.S. federal income tax consequences to holders of the CVRs.

For example, as discussed in the section titled “Agreements Related to the Merger—Contingent Value Rights Agreement—Material U.S. Federal Income Tax Consequences of the CVRs to Holders of Frequency Common Stock” beginning on page 218 of this proxy statement/prospectus, Frequency does not intend to report the issuance of the CVRs as a current distribution of property with respect to its stock, but it is possible that the IRS could assert that Frequency stockholders are treated as having received a distribution of property equal to the fair market value of the CVRs on the date the CVRs are distributed, which could be taxable to Frequency stockholders without the corresponding receipt of cash. In addition, it is possible that the IRS or a court could determine that the issuance of the CVRs (and/or any payments thereon) and the Reverse Stock Split constitute a single “recapitalization” for U.S. federal income tax purposes with the CVRs constituting taxable “boot” received in such recapitalization exchange. In such case, the tax consequences of the CVRs and the Reverse Stock Split would differ from those described in this proxy statement/prospectus, including with respect to the timing and character of income.

Risks Related to the Proposed Reverse Stock Split

The Reverse Stock Split may not increase the combined company’s stock price over the long-term.

The principal purpose of the Reverse Stock Split is to increase the per-share market price of Frequency common stock above the minimum bid price requirement under the Nasdaq rules so that Frequency can maintain

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its listing on Nasdaq. It cannot be assured, however, that the Reverse Stock Split will accomplish this objective for any meaningful period of time. While it is expected that the reduction in the number of outstanding shares of common stock will proportionally increase the market price of Frequency common stock, it cannot be assured that the Reverse Stock Split will increase the market price of its common stock by enough to maintain the listing of Frequency common stock on Nasdaq, or result in any permanent or sustained increase in the market price of Frequency common stock, which is dependent upon many factors, including Frequency’s business and financial performance, general market conditions, and prospects for future success. Thus, while the stock price of Frequency might meet the continued listing requirements for Nasdaq initially, it cannot be assured that it will continue to do so.

The Reverse Stock Split may decrease the liquidity of the combined company’s common stock.

Although the Frequency board of directors believes that the anticipated increase in the market price of the combined company’s common stock resulting from the proposed Reverse Stock Split could encourage interest in its common stock and possibly promote greater liquidity for its stockholders, such liquidity could also be adversely affected by the reduced number of shares outstanding after the Reverse Stock Split. The reduction in the number of outstanding shares may lead to reduced trading and a smaller number of market makers for the combined company’s common stock. In addition, the Reverse Stock Split may not result in an increase in the combined company’s stock price necessary to satisfy Nasdaq’s initial listing requirements for the combined company.

The Reverse Stock Split may lead to a decrease in the combined company’s overall market capitalization.

Should the market price of the combined company’s common stock decline after the Reverse Stock Split, the percentage decline may be greater, due to the smaller number of shares outstanding, than it would have been prior to the Reverse Stock Split. A Reverse Stock Split is often viewed negatively by the market and, consequently, can lead to a decrease in the combined company’s overall market capitalization. If the per share market price does not increase in proportion to the Reverse Stock Split ratio, then the value of the combined company, as measured by its stock capitalization, will be reduced. In some cases, the per-share stock price of companies that have effected reverse stock splits subsequently declined back to pre-reverse split levels, and accordingly, it cannot be assured that the total market value of the combined company’s common stock will remain the same after the Reverse Stock Split is effected, or that the Reverse Stock Split will not have an adverse effect on the combined company’s stock price due to the reduced number of shares outstanding after the Reverse Stock Split.

Risks Related to the Combined Company

If any of the events described in “Risks Related to Frequency’s Business” or “Risks Related to Korro Bio’s Business” occur, those events could cause potential benefits of the Merger not to be realized.

Following completion of the Merger, the combined company will be susceptible to many of the risks described in the sections herein entitled “Risks Related to Frequency’s Business” and “Risks Related to Korro Bio’s Business” beginning on pages 46 and 96. To the extent any of the events in the risks described in those sections occur, the potential benefits of the Merger may not be realized and the results of operations and financial condition of the combined company could be adversely affected in a material way. This could cause the market price of the combined company’s common stock to decline.

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The market price of the combined company’s common stock is expected to be volatile, and the market price of the common stock may drop following the Merger.

The market price of the combined company’s common stock following the Merger could be subject to significant fluctuations. Some of the factors that may cause the market price of the combined company’s common stock to fluctuate include:

Moreover, the stock markets in general have experienced substantial volatility that has often been unrelated to the operating performance of individual companies. These broad market fluctuations may also adversely affect the trading price of the combined company’s common stock. In addition, a recession, depression or other sustained adverse market event could materially and adversely affect the combined company’s business and the value of its common stock. In the past, following periods of volatility in the market price of a company’s

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securities, stockholders have often instituted class action securities litigation against such companies. Furthermore, market volatility may lead to increased shareholder activism if the combined company experiences a market valuation that activists believe is not reflective of its intrinsic value. Activist campaigns that contest or conflict with the combined company’s strategic direction or seek changes in the composition of its board of directors could have an adverse effect on its operating results, financial condition and cash flows.

The combined company may incur losses for the foreseeable future and might never achieve profitability.

The combined company may never become profitable, even if the combined company is able to complete clinical development for one or more product candidates and eventually commercialize such product candidates. The combined company will need to successfully complete significant research, development, testing and regulatory compliance activities that, together with projected general and administrative expenses, is expected to result in substantial increased operating losses for at least the next several years. Even if the combined company does achieve profitability, it may not be able to sustain or increase profitability on a quarterly or annual basis.

Following the Merger, the combined company may be unable to integrate successfully the businesses of Frequency and Korro Bio and realize the anticipated benefits of the Merger.

The Merger involves the combination of two companies that currently operate as independent companies. Following the Merger, the combined company will be required to devote significant management attention and resources to integrating its business practices and operations. The combined company may fail to realize some or all of the anticipated benefits of the Merger if the integration process takes longer than expected or is more costly than expected. Potential difficulties the combined company may encounter in the integration process include the following:

In addition, Frequency and Korro Bio have operated and, until the completion of the Merger, will continue to operate, independently. It is possible that the integration process also could result in the diversion of each company’s management’s attention, the disruption or interruption of, or the loss of momentum in, each company’s ongoing businesses or inconsistencies in standards, controls, procedures and policies, any of which could adversely affect the combined company’s ability to maintain its business relationships or the ability to achieve the anticipated benefits of the Merger, or could otherwise adversely affect the business and financial results of the combined company.

If the combined company fails to attract and retain management and other key personnel, it may be unable to continue to successfully develop or commercialize its product candidates or otherwise implement its business plan.

The combined company’s ability to compete in the highly competitive pharmaceuticals industry depends on its ability to attract and retain highly qualified managerial, scientific, medical, legal, sales and marketing and other personnel. The combined company will be highly dependent on its management and scientific personnel. The loss of the services of any of these individuals could impede, delay, or prevent the successful development of the combined company’s product pipeline, completion of its planned clinical trials, commercialization of its product candidates or in-licensing or acquisition of new assets and could impact negatively its ability to

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implement successfully its business plan. If the combined company loses the services of any of these individuals, it might not be able to find suitable replacements on a timely basis or at all, and its business could be harmed as a result. The combined company might not be able to attract or retain qualified management and other key personnel in the future due to the intense competition for qualified personnel among biotechnology, pharmaceutical and other businesses.

The combined company will need to raise additional financing in the future to fund its operations, which may not be available to it on favorable terms or at all.

The combined company will require substantial additional funds to conduct the costly and time-consuming clinical efficacy trials necessary to pursue regulatory approval of each potential product candidate. The combined company’s future capital requirements will depend upon a number of factors, including: the number and timing of future product candidates in the pipeline; progress with and results from preclinical testing and clinical trials; the ability to manufacture sufficient drug supplies to complete preclinical and clinical trials; the costs involved in preparing, filing, acquiring, prosecuting, maintaining and enforcing patent and other intellectual property claims; and the time and costs involved in obtaining regulatory approvals and favorable reimbursement or formulary acceptance. Raising additional capital may be costly or difficult to obtain and could, for example, through the sale of common stock or securities convertible or exchangeable into common stock, significantly dilute its stockholders’ ownership interests or inhibit the combined company’s ability to achieve its business objectives. If the combined company raises additional funds through public or private equity offerings, the terms of these securities may include liquidation or other preferences that adversely the rights of its common stockholders. In addition, any debt financing may subject the combined company to fixed payment obligations and covenants limiting or restricting its ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If the combined company raises additional capital through marketing and distribution arrangements or other collaborations, strategic alliances or licensing arrangements with third parties, the combined company may have to relinquish certain valuable intellectual property or other rights to its product candidates, technologies, future revenue streams or research programs or grant licenses on terms that may not be favorable to it. Even if the combined company were to obtain sufficient funding, there can be no assurance that it will be available on terms acceptable to the combined company or its stockholders.

The combined company will incur additional costs and increased demands upon management as a result of complying with the laws and regulations affecting public companies.

The combined company will incur significant legal, accounting and other expenses as a public company that Korro Bio did not incur as a private company, including costs associated with public company reporting obligations under the Securities Exchange Act of 1934, as amended, or the Exchange Act. The combined company’s management team will consist of the executive officers of Korro Bio prior to the Merger, some of whom have not previously managed and operated a public company. These executive officers and other personnel will need to devote substantial time to gaining expertise related to public company reporting requirements and compliance with applicable laws and regulations to ensure that the combined company complies with all of these requirements. Any changes the combined company makes to comply with these obligations may not be sufficient to allow it to satisfy its obligations as a public company on a timely basis, or at all. These reporting requirements, rules and regulations, coupled with the increase in potential litigation exposure associated with being a public company, could also make it more difficult for the combined company to attract and retain qualified persons to serve on the board of directors or on board committees or to serve as executive officers, or to obtain certain types of insurance, including directors’ and officers’ insurance, on acceptable terms.

Upon completion of the Merger, failure by the combined company to comply with the initial listing standards of Nasdaq will prevent its stock from being listed on Nasdaq.

Upon completion of the Merger, Frequency, under the new name “Korro Bio, Inc.,” will be required to meet the initial listing requirements to maintain the listing and continued trading of its shares on Nasdaq. These initial

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listing requirements are more difficult to achieve than the continued listing requirements. Pursuant to the Merger Agreement, Frequency agreed to use its commercially reasonable efforts to cause the shares of Frequency common stock being issued in the Merger to be approved for listing on Nasdaq at or prior to the Effective Time. Based on information currently available to Frequency, Frequency anticipates that its stock will be unable to meet the $4.00 (or, to the extent applicable, $3.00) minimum bid price initial listing requirement at the closing of the Merger unless it effects a reverse stock split. The board of directors of Frequency intends to effect a reverse stock split of the shares of Frequency common stock at a ratio of between 1:                 to 1:                . In addition, often times a reverse stock split will not result in a trading price for the affected common stock that is proportional to the ratio of the split. Following the Merger, if the combined company is unable to satisfy Nasdaq listing requirements, Nasdaq may notify the combined company that its shares of common stock will not be listed on Nasdaq.

Upon a potential delisting from Nasdaq, if the common stock of the combined company is not then eligible for quotation on another market or exchange, trading of the shares could be conducted in the over-the-counter market or on an electronic bulletin board established for unlisted securities such as the Pink Sheets or the OTC Bulletin Board. In such event, it is likely that there would be significantly less liquidity in the trading of the common stock of the combined company; decreases in institutional and other investor demand for the shares, coverage by securities analysts, market making activity and information available concerning trading prices and volume; and fewer broker dealers willing to execute trades in the common stock of the combined company. Also, it may be difficult for the combined company to raise additional capital if the combined company’s common stock is not listed on a major exchange. The occurrence of any of these events could result in a further decline in the market price of the common stock of the combined company and could have a material adverse effect on the combined company.

Once the combined company is no longer an emerging growth company, a smaller reporting company or otherwise no longer qualifies for applicable exemptions, the combined company will be subject to additional laws and regulations affecting public companies that will increase the combined company’s costs and the demands on management and could harm the combined company’s operating results and cash flows.

The combined company will be subject to the reporting requirements of the Exchange Act, which requires, among other things, that the combined company file with the SEC, annual, quarterly and current reports with respect to the combined company’s business and financial condition as well as other disclosure and corporate governance requirements. However, as an emerging growth company, the combined company may take advantage of exemptions from various requirements such as an exemption from the requirement to have the combined company’s independent auditors attest to the combined company’s internal control over financial reporting under Section 404 of the Sarbanes-Oxley Act of 2002 as well as an exemption from the “say on pay” voting requirements pursuant to the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010. The combined company will no longer qualify as an emerging growth company after December 31, 2023. After the combined company no longer qualifies as an emerging growth company, Frequency and Korro Bio expect the combined company to still qualify as a “smaller reporting company,” as such term is defined in Rule 12b-2 under the Exchange Act, in at least the near term, which will allow the combined company to take advantage of many of the same exemptions from disclosure requirements, including not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act and reduced disclosure obligations regarding executive compensation in this proxy statement/prospectus and in the combined company’s periodic reports and proxy statements. Once the combined company is no longer an emerging growth company or a smaller reporting company or otherwise no longer qualifies for these exemptions, the combined company will be required to comply with these additional legal and regulatory requirements applicable to public companies and will incur significant legal, accounting and other expenses to do so. If the combined company is not able to comply with the requirements in a timely manner or at all, the combined company’s financial condition or the market price of the combined company’s common stock may be harmed. For example, if the combined company or its independent auditor identifies deficiencies in the combined company’s internal control over financial reporting that are deemed to be material weaknesses the combined company could face additional costs to remedy those

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deficiencies, the market price of the combined company’s stock could decline or the combined company could be subject to sanctions or investigations by the SEC or other regulatory authorities, which would require additional financial and management resources.

If the combined company fails to maintain proper and effective internal controls, its ability to produce accurate financial statements on a timely basis could be impaired.

Provided the combined company continues to be listed on Nasdaq, the combined company will be subject to the reporting requirements of the Exchange Act, the Sarbanes-Oxley Act and the rules and regulations of Nasdaq. The Sarbanes-Oxley Act requires, among other things, that the combined company maintain effective disclosure controls and procedures and internal control over financial reporting. The combined company must perform system and process evaluation and testing of its internal control over financial reporting to allow management to report on the effectiveness of its internal controls over financial reporting in its Annual Report on Form 10-K filing for that year, as required by Section 404 of the Sarbanes-Oxley Act. As a private company, Korro Bio has never been required to test its internal controls within a specified period. This will require that the combined company incur substantial professional fees and internal costs to expand its accounting and finance functions and that it expends significant management efforts. The combined company may experience difficulty in meeting these reporting requirements in a timely manner.

The combined company may discover weaknesses in its system of internal financial and accounting controls and procedures that could result in a material misstatement of its financial statements. The combined company’s internal control over financial reporting will not prevent or detect all errors and all fraud. A control system, no matter how well designed and operated, can provide only reasonable, not absolute, assurance that the control system’s objectives will be met. Because of the inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that misstatements due to error or fraud will not occur or that all control issues and instances of fraud will be detected.

If the combined company is not able to comply with the requirements of Section 404 of the Sarbanes-Oxley Act, or if it is unable to maintain proper and effective internal controls, the combined company may not be able to produce timely and accurate financial statements. If that were to happen, the market price of its common stock could decline and it could be subject to sanctions or investigations by Nasdaq, the SEC or other regulatory authorities.

The unaudited pro forma condensed combined financial information for Frequency and Korro Bio included in this proxy statement/prospectus are preliminary, and the combined company’s actual financial position and operations after the Merger may differ materially from the unaudited pro forma financial information included in this proxy statement/prospectus.

The unaudited pro forma financial information for Frequency and Korro Bio included in this proxy statement/prospectus are presented for illustrative purposes only and is not necessarily indicative of the combined company’s actual financial condition or results of operations of future periods, or the financial condition or results of operations that would have been realized had the entities been combined during the period presented. The combined company’s actual results and financial position after the Merger may differ materially and adversely from the unaudited pro forma financial information included in this proxy statement/prospectus. The exchange ratio formula reflected in this proxy statement/prospectus is preliminary. The final exchange ratio will be determined in accordance with the formula in the Merger Agreement and could differ materially from the preliminary exchange ratio used to prepare the pro forma adjustments. For more information see the section titled “Unaudited Pro Forma Condensed Combined Financial Information” beginning on page 362.

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The combined company’s certificate of incorporation and bylaws and provisions under Delaware law could make an acquisition of the combined company more difficult and may prevent attempts by its stockholders to replace or remove its management.

If the Merger is completed, Frequency’s bylaws and Frequency’s charter, as amended by the amendments thereto attached to this proxy statement/prospectus as Annex H and, assuming Proposal No. 2 are approved by Frequency stockholders at the Frequency Annual Meeting, will become the combined company’s bylaws and certificate of incorporation. Provisions that will be included in the combined company’s certificate of incorporation and bylaws may discourage, delay or prevent a merger, acquisition or other change in control of the combined company that stockholders may consider favorable, including transactions in which its common stockholders might otherwise receive a premium price for their shares. These provisions could also limit the price that investors might be willing to pay in the future for shares of the combined company’s common stock, thereby depressing the market price of its common stock. In addition, because the combined company’s board of directors will be responsible for appointing the members of the combined company’s management team, these provisions may frustrate or prevent any attempts by the combined company’s stockholders to replace or remove its current management by making it more difficult for stockholders to replace members of the combined company’s board of directors. Among other things, these provisions:

Moreover, because the combined company will be incorporated in Delaware, it is governed by the provisions of Section 203 of the DGCL, which prohibits stockholders owning in excess of 15% of the outstanding combined company voting stock from merging or combining with the combined company. Although Frequency and Korro Bio believe these provisions collectively will provide for an opportunity to receive higher bids by requiring potential acquirors to negotiate with the combined company’s board of directors, they would apply even if the offer may be considered beneficial by some stockholders. In addition, these provisions may frustrate or prevent any attempts by the combined company’s stockholders to replace or remove then current management by making it more difficult for stockholders to replace members of the board of directors, which is responsible for appointing the members of management.

The bylaws of the combined company will provide that, unless the combined company consents in writing to the selection of an alternative forum, certain designated courts will be the sole and exclusive forum for certain legal actions between the combined company and its stockholders, which could limit its stockholders’ ability to obtain a favorable judicial forum for disputes with the combined company or its directors, officers, employees or agents.

The bylaws of the combined company will provide that, unless it consents in writing to an alternative forum, the Court of Chancery of the State of Delaware is the sole and exclusive forum for state law claims for (i) any

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derivative action or proceeding brought on its behalf, (ii) any action asserting a claim of or based on a breach of a fiduciary duty owed by any of its current or former directors, officers, or other employees to the combined company or its stockholders, (iii) any action asserting a claim arising pursuant to any provision of the DGCL, its charter or its bylaws, or (iv) any action asserting a claim that is governed by the internal affairs doctrine, in each case subject to the Court of Chancery having personal jurisdiction over the indispensable parties named as defendants therein, which for purposes of this risk factor refers to herein as the “Delaware Forum Provision.” The Delaware Forum Provision will not apply to any causes of action arising under the Securities Act and the Exchange Act. The bylaws of the combined company will further provide that, unless it consents in writing to an alternative forum, federal district courts of the United States will be the exclusive forum for resolving any complaint asserting a cause of action arising under the Securities Act, which for purposes of this risk factor refers to herein as the “Federal Forum Provision.” In addition, the bylaws of the combined company will provide that any person or entity purchasing or otherwise acquiring any interest in shares of its capital stock is deemed to have notice of and consented to the foregoing Delaware Forum Provision and Federal Forum Provision; provided, however, that stockholders cannot and will not be deemed to have waived its compliance with the U.S. federal securities laws and the rules and regulations thereunder.

The Delaware Forum Provision and the Federal Forum Provision may impose additional litigation costs on stockholders of the combined company in pursuing any such claims, particularly if the stockholders do not reside in or near the State of Delaware. Additionally, the forum selection clauses in the bylaws of the combined company may limit its stockholders’ ability to bring a claim in a judicial forum that they find favorable for disputes with the combined company or its directors, officers or employees, which may discourage such lawsuits against the combined company and its directors, officers and employees even though an action, if successful, might benefit its stockholders.

Frequency and Korro Bio do not anticipate that the combined company will pay any cash dividends in the foreseeable future.

The current expectation is that the combined company will retain its future earnings, if any, to fund the growth of the combined company’s business as opposed to paying dividends. As a result, capital appreciation, if any, of the common stock of the combined company will be your sole source of gain, if any, for the foreseeable future.

An active trading market for the combined company’s common stock may not develop and its stockholders may not be able to resell their shares of common stock for a profit, if at all.

Prior to the Merger, there had been no public market for shares of Korro Bio capital stock. An active trading market for the combined company’s shares of common stock may never develop or be sustained. If an active market for the combined company’s common stock does not develop or is not sustained, it may be difficult for its stockholders to sell their shares at an attractive price or at all.

Future sales of shares by existing stockholders could cause the combined company’s stock price to decline.

If existing securityholders of Frequency and Korro Bio sell, or indicate an intention to sell, substantial amounts of the combined company’s common stock in the public market after legal restrictions on resale discussed in this proxy statement/prospectus lapse, the trading price of the common stock of the combined company could decline. Based on shares outstanding as of                , after giving effect to the estimated exchange ratio, which has been adjusted to reflect the proposed Reverse Stock Split, the Pre-Closing Financing and shares expected to be issued upon completion of the Merger, the combined company is expected to have outstanding a total of approximately                shares of common stock immediately following the completion of the Merger. Of the shares of common stock, approximately                 shares will be available for sale in the public market beginning 180 days after the closing of the Merger as a result of the expiration of lock-up agreements between Frequency and Korro Bio on the one hand and certain securityholders of Frequency

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and Korro Bio on the other hand. All other outstanding shares of common stock, other than shares held by affiliates of the combined company and shares of Frequency common stock issued in exchange for shares of Korro Bio common stock issued in the Pre-Closing Financing will be freely tradable, without restriction, in the public market. In addition, shares of common stock that are subject to outstanding options or warrants of Korro Bio will become eligible for sale in the public market to the extent permitted by the provisions of various vesting agreements and Rules 144 and 701 under the Securities Act. If these shares are sold, the trading price of the combined company’s common stock could decline.

After completion of the Merger, the combined company’s executive officers, directors and principal stockholders will have the ability to control or significantly influence all matters submitted to the combined company’s stockholders for approval.

Upon the completion of the Merger, and giving effect to the issuance of the Pre-Closing Financing, it is anticipated that the combined company’s executive officers, directors and principal stockholders will, in the aggregate, beneficially own approximately         % of the combined company’s outstanding shares of common stock, subject to certain assumptions, including, but not limited to, Frequency’s net cash as of closing being not less than $             million or greater than $             million. As a result, if these stockholders were to choose to act together, they would be able to control or significantly influence all matters submitted to the combined company’s stockholders for approval, as well as the combined company’s management and affairs. For example, these stockholders, if they choose to act together, would control or significantly influence the election of directors and approval of any merger, consolidation or sale of all or substantially all of the combined company’s assets. This concentration of voting power could delay or prevent an acquisition of the combined company on terms that other stockholders may desire.

If equity research analysts do not publish research or reports, or publish unfavorable research or reports, about the combined company, its business or its market, its stock price and trading volume could decline.

The trading market for the combined company’s common stock will be influenced by the research and reports that equity research analysts publish about it and its business. Equity research analysts may elect to not provide research coverage of the combined company’s common stock after the completion of the Merger, and such lack of research coverage may adversely affect the market price of its common stock. In the event it does have equity research analyst coverage, the combined company will not have any control over the analysts or the content and opinions included in their reports. The price of the combined company’s common stock could decline if one or more equity research analysts downgrade its stock or issue other unfavorable commentary or research. If one or more equity research analysts ceases coverage of the combined company or fails to publish reports on it regularly, demand for its common stock could decrease, which in turn could cause its stock price or trading volume to decline.

The combined company will have broad discretion in the use of the cash and cash equivalents of the combined company and the proceeds from the Pre-Closing Financing and may invest or spend the proceeds in ways with which you do not agree and in ways that may not increase the value of your investment.

The combined company will have broad discretion over the use of the cash and cash equivalents of the combined company and the proceeds from the Pre-Closing Financing. You may not agree with the combined company’s decisions, and its use of the proceeds may not yield any return on your investment. The combined company’s failure to apply these resources effectively could compromise its ability to pursue its growth strategy and the combined company might not be able to yield a significant return, if any, on its investment of these net proceeds. You will not have the opportunity to influence its decisions on how to use the combined company’s cash resources.

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Changes in tax laws or in their implementation or interpretation may adversely affect the combined company’s business and financial condition.

The rules dealing with U.S. federal, state and local income taxation are constantly under review by persons involved in the legislative process and by the Internal Revenue Service and the U.S. Treasury Department. Changes to tax laws (which changes may have retroactive application) could adversely affect the combined company’s business and financial condition. In recent years, many such changes have been made and changes are likely to continue to occur in the future. The combined company cannot predict whether, when, in what form or with what effective dates, tax laws, regulations and rulings may be enacted, promulgated or decided or whether they could increase its tax liability or require changes in the manner in which it operates in order to minimize increases in its tax liability.

The combined company’s ability to use net operating loss carryforwards and other tax attributes may be limited, including as a result of the Merger.

The combined company’s ability to utilize net operating loss carryforwards, or NOLs, and other tax attributes to offset future taxable income or tax liabilities may be limited as a result of ownership changes, including, as discussed below, in connection with the Merger or other transactions. Similar rules may apply under state tax laws. If the combined company earns taxable income, such limitations could result in increased future income tax liability to the combined company, and the combined company’s future cash flows could be adversely affected.

For a more complete discussion of the risks related to the net operating loss carryforwards and certain other tax attributes of Frequency and Korro Bio, please see the discussions under “Risk Factors—Risks Related to Frequency’s Business—Risks Related to Frequency’s financial position and need for additional capital—Frequency’s ability to use its net operating loss carryforwards to offset future taxable income, or tax credit carryforwards to offset future income tax liabilities, may be subject to certain limitations” and “Risk Factors—Risks Related to Korro Bio’s Financial Position and Need for Capital—Korro Bio’s ability to utilize its net operating loss carryforwards and certain other tax attributes may be limited,” respectively.

Unfavorable global economic conditions could adversely affect the combined company’s business, financial condition, results of operations or cash flows.

The combined company’s results of operations could be adversely affected by general conditions in the global economy and in the global financial markets. A severe or prolonged economic downturn could result in a variety of risks to the combined company’s business, including, weakened demand for the combined company’s product candidates and the combined company’s ability to raise additional capital when needed on acceptable terms, if at all. A weak or declining economy could also strain the combined company’s suppliers, possibly resulting in supply disruption, or cause the combined company’s customers to delay making payments for its services. Any of the foregoing could harm the combined company’s business and the combined company cannot anticipate all of the ways in which the current economic climate and financial market conditions could adversely impact its business.

Risks Related to Frequency’s Business

Risks related to Frequency’s financial position and need for additional capital

Frequency has incurred significant losses since inception and anticipates that Frequency will continue to incur losses for the foreseeable future. Frequency is not currently profitable, and Frequency may never achieve or sustain profitability. If Frequency is unable to achieve or sustain profitability, the market value of Frequency common stock will likely decline.

Frequency is a preclinical-stage biotechnology company with a limited operating history. As a result, Frequency is not profitable and has incurred significant losses since the formation. Frequency had net losses of

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$19.5 million and $81.6 million for the three months ended March 31, 2023, and the year ended December 31, 2022, respectively. As of March 31, 2023, Frequency had an accumulated deficit of $281.2 million. Investment in biopharmaceutical product development is highly speculative because it entails substantial upfront capital expenditures and significant risk that any potential product candidate will fail to gain regulatory approval and become commercially viable. Frequency has not commercialized any products and has never generated revenue from the commercialization of any product. To date, Frequency has devoted most of its financial resources to licensing technologies and research and development, including its preclinical platform development activities and clinical trials.

Frequency expects to incur significant additional operating losses to advance any product candidate, including a potential therapeutic candidate for MS, through clinical development, clinical trials, regulatory approval and commercialization. The costs of advancing product candidates into each clinical phase tend to increase substantially over the duration of the clinical development process. Therefore, the total costs to advance any product candidate to marketing approval in even a single jurisdiction are substantial. Because of the numerous risks and uncertainties associated with pharmaceutical product development, Frequency is unable to accurately predict the timing or amount of increased expenses or when, or if, Frequency will be able to begin generating revenue from the commercialization of any product candidates or achieve or maintain profitability. Frequency’s expenses will also increase substantially if Frequency:

Furthermore, Frequency’s ability to successfully develop, commercialize and license any product candidates and generate product revenue is subject to substantial additional risks and uncertainties, as described under “Risks related to development, clinical testing, manufacturing, and regulatory approval” and “Risks related to commercialization.” As a result, Frequency expects to continue to incur net losses and negative cash flows for the foreseeable future. These net losses and negative cash flows have had, and will continue to have, an adverse effect on Frequency’s stockholders’ equity and working capital. The amount of its future net losses will depend, in part, on the rate of future growth of its expenses and its ability to generate revenues. If Frequency is unable to develop and commercialize one or more product candidates, either alone or through collaborations, or if revenues from any product that receives marketing approval are insufficient, Frequency will not achieve profitability. Even if Frequency successfully commercializes any product candidates, Frequency may continue to incur substantial research and development and other expenses to identify and develop other product candidates. Even if Frequency does achieve profitability, Frequency may not be able to sustain profitability or meet outside expectations for its profitability. If Frequency is unable to achieve or sustain profitability or to meet outside expectations for its profitability, the value of Frequency common stock will be materially adversely affected.

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Frequency will require additional capital to fund its operations, and if Frequency fails to obtain necessary financing, Frequency may not be able to complete the development and commercialization of any product candidates or explore additional product candidates.

Frequency will require additional capital to enable Frequency to develop any product candidate, which it may acquire through equity offerings, debt financings, marketing and distribution arrangements and other collaborations, strategic alliances and licensing arrangements or other sources. Adequate additional financing may not be available to Frequency on acceptable terms, or at all. Frequency’s failure to raise capital as and when needed would have a negative effect on Frequency’s financial condition and its ability to pursue its business strategy. In addition, attempting to secure additional financing may divert the time and attention of Frequency’s management from day-to-day activities and harm its development efforts.

Changing circumstances, including any unanticipated expenses, could cause Frequency to consume capital significantly faster than Frequency currently anticipates, and Frequency may need to spend more than currently expected because of circumstances beyond its control. Because the length of time and scope of activities associated with successful development of any product candidate Frequency may develop is highly uncertain, Frequency is unable to estimate the actual funds it will require for development and any marketing and commercialization activities. Its future funding requirements, both near and long-term, will depend on many factors, including, but not limited to:

Depending on its business performance, the economic climate and market conditions, Frequency may be unable to raise additional funds through any sources. Market volatility resulting from the COVID-19 global pandemic, international geopolitical conflict, global supply chain issues, and increased inflation could also adversely impact its ability to access capital as and when needed. If Frequency is unable to raise additional capital in sufficient amounts or on terms acceptable to Frequency, Frequency may have to significantly delay, scale back or discontinue the development or commercialization of any product candidates, or potentially discontinue operations.

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Additionally, Frequency maintains the majority of its cash and cash equivalents in accounts with major U.S. and multi-national financial institutions, and its deposits at certain of these institutions exceed insured limits. Market conditions can impact the viability of these institutions. In the event of failure of any of the financial institutions where Frequency maintains its cash and cash equivalents, there can be no assurance that Frequency would be able to access uninsured funds in a timely manner or at all. Any inability to access or delay in accessing these funds could adversely affect its business and financial position.

Frequency has a limited operating history and no history of commercializing pharmaceutical products, which may make it difficult to evaluate the prospects for its future viability.

Frequency was established and began operations in 2014. Its operations to date have been limited to financing and staffing Frequency, licensing technologies, developing its PCA approach, developing and conducting preclinical and clinical studies for the treatment of SNHL, and developing a pipeline of preclinical and research programs, including its remyelination program in MS. Frequency has not yet demonstrated the ability to successfully complete a large-scale, pivotal clinical trial, obtain marketing approval, manufacture a commercial-scale product, or arrange for a third party to do so on Frequency’s behalf, or conduct sales and marketing activities necessary for successful product commercialization. Consequently, predictions about its future success or viability may not be as accurate as they could be if Frequency had a longer operating history or a history of successfully developing and commercializing pharmaceutical products.

In addition, as a business with a limited operating history, Frequency may encounter unforeseen expenses, difficulties, complications, delays and other known and unknown challenges. Its FX-322 Phase 2b results (FX-322-208), for example, showed no statistically significant difference at day 90 between those administered FX-322 versus those receiving placebo in the proportion of individuals that demonstrated an improvement in speech perception. Frequency will eventually need to transition from a company with a research focus to a company capable of supporting commercial activities. Frequency may not be successful in such a transition and, as a result, its business may be adversely affected.

Frequency expects its financial condition and operating results may fluctuate significantly from quarter to quarter and year to year due to a variety of factors, many of which are beyond its control. Accordingly, the results of any quarterly or annual period are not necessarily indicative of future operating performance.

Frequency’s ability to use its net operating loss carryforwards to offset future taxable income, or tax credit carryforwards to offset future income tax liabilities, may be subject to certain limitations.

As of December 31, 2022, Frequency had NOLs of $174.1 million for federal income tax purposes and $141.3 million for state income tax purposes, which may be available to offset its future taxable income, if any. Frequency’s NOLs expire in various amounts through 2042, provided that federal NOLs generated in taxable years beginning after December 31, 2017, will not be subject to expiration. However, although federal NOLs generated in taxable years beginning after December 31, 2017, may be carried forward indefinitely, such NOLs may only be used to offset 80% of Frequency’s taxable income in taxable years beginning after December 31, 2020, which may require Frequency to pay federal income taxes in future years despite generating federal NOLs in prior years. As of December 31, 2022, Frequency also had federal and state research and development and other tax credit carryforwards of approximately $8.2 million and $3.6 million, respectively, available to reduce future income tax liabilities. Frequency’s tax credit carryforwards expire at various dates through 2042. These NOLs and tax credit carryforwards could expire unused, to the extent subject to expiration, and be unavailable to offset future taxable income or income tax liabilities, as applicable.

In addition, in general, under Sections 382 and 383 of the Code, a corporation that undergoes an “ownership change” is subject to limitations on its ability to use its pre-change NOLs and tax credit carryforwards to offset future taxable income. For these purposes, an ownership change generally occurs where one or more stockholders or groups of stockholders who owns at least 5% of a corporation’s stock increases their ownership

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by more than 50 percentage points over their lowest ownership percentage within a rolling three-year period. Similar rules may apply under state tax laws. Frequency believes it has experienced ownership changes in 2017 and 2019. As a result of the ownership changes in 2017 and 2019, $0.01 million and $0.04 million of NOL carryforwards are limited under Section 382 of the Code. Frequency may experience ownership changes in the future as a result of future transactions in its stock, some of which may be outside its control. In particular, the Merger and the Pre-Closing Financing, if consummated, are likely to constitute an ownership change within the meaning of Section 382 of the Code, which could eliminate or otherwise substantially limit Frequency’s ability to use its NOLs and tax credit carryforwards. For these reasons, Frequency may not be able to use a material portion of its NOLs or tax credit carryforwards, even if Frequency attains profitability. Frequency has recorded a full valuation allowance related to its NOLs and other deferred tax assets due to the uncertainty of the ultimate realization of the future tax benefit of such assets.

Changes in tax laws or in their implementation or interpretation may adversely affect Frequency’s business and financial condition.

The rules dealing with U.S. federal, state and local income taxation are constantly under review by persons involved in the legislative process and by the Internal Revenue Service and the U.S. Treasury Department. Changes to tax laws (which changes may have retroactive application) could adversely affect Frequency’s business and financial condition. In recent years, many such changes have been made and changes are likely to continue to occur in the future. Frequency cannot predict whether, when, in what form or with what effective dates, tax laws, regulations and rulings may be enacted, promulgated or decided or whether they could increase its tax liability or require changes in the manner in which it operates in order to minimize increases in its tax liability.

Risks related to development, clinical testing, manufacturing, and regulatory approval

Frequency is heavily dependent on the MS Program, and if it is unable to enter into a strategic transaction for its MS Program, or is unable to develop an MS product candidate or such MS product candidate does not receive regulatory approval or is not successfully commercialized, its business could be materially adversely harmed.

To date, Frequency has invested a significant portion of its efforts and financial resources in the development of FX-322 for the treatment of SNHL. Frequency recently discontinued its FX-322 and FX-345 development programs following the results of its FX-322 Phase 2b study which showed no statistically significant difference at day 90 between those administered FX-322 versus those receiving placebo in the proportion of individuals that demonstrated an improvement in speech perception. Frequency’s future success is substantially dependent on its ability to successfully enter into a strategic transaction for its MS Program or complete development for, obtain regulatory approval for, and successfully commercialize an MS product candidate, which may never occur. Frequency currently has no products that are approved for commercial sale and may never be able to develop a marketable product. An MS development program will require a substantial portion of Frequency’s efforts and expenditures and will require clinical development, management of clinical and manufacturing activities, regulatory approval, establishing commercial scale manufacturing, and significant sales, marketing, and distribution efforts before Frequency can generate any revenues from any commercial sales. Frequency cannot be certain that it will be able to successfully complete any of these activities or that, even if it receives regulatory approval, a remyelinating therapeutic will be as effective as anticipated at treating MS.

The research, testing, manufacturing, labeling, approval, sale, packaging, marketing, and distribution of drug products are subject to extensive regulation by the FDA and comparable regulatory authorities in other countries. Frequency is not permitted to market an MS product candidate until Frequency receive regulatory approval from the FDA or comparable regulatory authorities in other countries, and Frequency may never receive such regulatory approval. Furthermore, Frequency cannot be certain that it will be able to enter into any strategic transaction for the MS Program or that it will be able to enter into a strategic transaction on favorable terms. As a result, its financial position could be materially adversely affected, and Frequency may not be able to generate sufficient revenue to continue its business.

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Frequency utilizes its PCA approach to develop product candidates that are designed to activate progenitor cells, which is a new approach to therapeutic intervention and, as a result, successful development, approval, and commercialization of any product candidates, including an MS product candidate, is uncertain.

Frequency utilizes its PCA approach to develop product candidates, including in its MS development program. Frequency’s PCA approach is designed to identify pathways to activate progenitor cells already present in the body to treat conditions or diseases through cellular regeneration. Frequency has not, nor to its knowledge has any other company, received regulatory approval utilizing this mechanism of cellular regeneration. Given the novelty of its approach, Frequency could encounter a longer than expected regulatory review process, increased development costs, or unexpected delays in, or even prevention of, the regulatory approval and commercialization of its product candidates, and Frequency cannot be certain that its approach will lead to the development of any approvable or marketable products.

Clinical trials are expensive, time consuming, and difficult to design and implement, and involve an uncertain outcome. The results of preclinical studies and early clinical trials are not always predictive of future results. Any product candidate that Frequency advances into clinical trials may not achieve favorable results in later clinical trials, if any, or receive marketing approval.

Clinical testing is expensive and can take many years to complete, and its outcome is inherently uncertain. Failure can occur at any time during the clinical trial process. The results of preclinical studies and completed clinical trials are not necessarily predictive of future results, and any product candidates Frequency develops may not be further developed or may have additional unfavorable results in later studies or trials. Clinical trial failure may result from a multitude of factors, including, but not limited to, flaws in study design, dose selection, placebo effect, subject enrollment criteria, selection of subjects based on subject misrepresentations, and failure to demonstrate favorable safety or efficacy traits. As such, failure in clinical trials can occur at any stage of testing, which may result in setbacks in development or a determination to no longer pursue a particular product candidate or indication. For example, later-stage clinical trials in its hearing program failed to meet their primary end points despite promising results from earlier clinical trials and, as a result, Frequency ended its hearing program. Further, based upon negative or inconclusive results or a need for additional information, Frequency may decide, or regulatory authorities may require Frequency, to conduct additional clinical trials or preclinical studies.

Frequency may experience delays in initiating and completing any clinical trials that Frequency intends to conduct, and Frequency does not know whether its clinical trials will begin on time, need to be redesigned, enroll subjects on time, or be completed on schedule, or at all. Clinical trials can be delayed for a variety of reasons, including delays related to:

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Frequency could also encounter delays if a clinical trial is suspended or terminated by Frequency, the IRBs or IECs of the institutions in which such trials are being conducted, the FDA or other regulatory authorities, or recommended for termination by a Data and Safety Monitoring Board, or DSMB, for such trial. Such authorities may impose a suspension or termination or recommend an alteration due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or its clinical protocols, inspection of the clinical trial operations or trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a drug, changes in governmental regulations or administrative actions, or lack of adequate funding to continue the clinical trial.

Furthermore, Frequency relies on CROs and clinical trial sites to ensure the proper and timely conduct of its clinical trials and, while Frequency has agreements governing its committed activities, Frequency has limited influence over its actual performance, as described in the section titled “Risks related to Frequency’s dependence on third parties.”

If Frequency experiences delays in the commencement or completion of any clinical trials, or if Frequency terminates a clinical trial prior to completion, the commercial prospects of any product candidate Frequency develops could be harmed, and its ability to generate revenues may be delayed. In addition, any delays in its clinical trials could increase its costs, slow the development and approval process and jeopardize its ability to commence product sales and generate revenues. Any of these occurrences may materially harm its business, financial condition, and results of operations. In addition, many of the factors that may cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval of its product candidates.

The regulatory approval processes of the FDA and comparable foreign regulatory authorities are lengthy, time- consuming, and inherently unpredictable, and if Frequency is ultimately unable to obtain regulatory approval for any product candidates, its business will be substantially harmed.

The time required to obtain approval by the FDA and comparable foreign regulatory authorities is unpredictable but typically takes many years following the commencement of clinical trials and depends upon numerous factors, including the substantial discretion of the regulatory authorities. In addition, approval policies, regulations, or the type and amount of clinical data necessary to gain approval may change during a product candidate’s clinical development and may vary among jurisdictions. The approval process may also be delayed by changes in government regulation, future legislation or administrative action. Frequency has not obtained regulatory approval for any product candidate and it is possible that Frequency will never obtain regulatory approval for any product candidate. Frequency is not permitted to market any of its product candidates in the United States until Frequency receives approval of an NDA from the FDA.

Prior to obtaining approval to commercialize a product candidate in the United States or abroad, Frequency must demonstrate with substantial evidence from well-controlled clinical trials, and to the satisfaction of the FDA or comparable foreign regulatory authority, that such product candidates are safe and effective for their intended uses. In addition, data obtained from preclinical trials and clinical trials are susceptible to varying interpretations, and regulatory authorities may not interpret its data as favorably as Frequency does, which may further delay, limit, or prevent development efforts, clinical trials, or marketing approval. Furthermore, as more competing drug candidates within a class of drugs proceed through clinical development to regulatory review and approval,

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the amount and type of clinical data that may be required by regulatory authorities may increase or change. Even if Frequency believes the preclinical or clinical data for its product candidates are promising, such data may not be sufficient to support approval by the FDA and other comparable regulatory authorities.

The FDA or any foreign regulatory authority can delay, limit, or deny approval of a product candidate that Frequency develops or requires Frequency to conduct additional preclinical or clinical testing or abandon a program for many reasons, including:

Of the large number of drugs in development, only a small percentage successfully complete the regulatory approval processes and are commercialized. This lengthy approval process, as well as the unpredictability of future clinical trial results, may result in Frequency’s failing to obtain regulatory approval to market its product candidates, which would significantly harm its business, results of operations, and prospects.

In addition, the FDA or the applicable foreign regulatory authority also may approve a product candidate for a more limited indication or patient population than Frequency originally requested, and the FDA or applicable foreign regulatory authority may approve a product candidate with a label that does not include the labeling claims necessary or desirable for the successful commercialization of that product candidate. Any of the foregoing circumstances could materially harm the commercial prospects for its product candidates and its business.

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Enrollment and retention of individuals in clinical trials is an expensive and time-consuming process and could be made more difficult or rendered impossible by multiple factors outside Frequency’s control.

The timely completion of clinical trials in accordance with their protocols depends, among other things, on Frequency’s ability to enroll a sufficient number of subjects who remain in the study until its conclusion. Frequency may encounter delays in enrolling, or be unable to enroll, a sufficient number of subjects to complete any of its clinical trials, and even once enrolled, Frequency may be unable to retain a sufficient number of subjects to complete any of its trials.

Subject enrollment and retention in clinical trials depends on many factors, including:

In addition, Frequency’s clinical trials will compete with other clinical trials for product candidates that are in the same therapeutic areas as its product candidates, and this competition will reduce the number and types of subjects available to Frequency, because some people who might have opted to enroll in its trials may instead opt to enroll in a trial being conducted by one of its competitors. Furthermore, any negative results Frequency may report in clinical trials of any product candidate may make it difficult or impossible to recruit and retain people in other clinical trials of that same product candidate. Delays or failures in planned subject enrollment or retention may result in increased costs or program delays, which could have a harmful effect on its ability to develop a product candidate or could render further development impossible.

Results of preclinical studies, clinical trials, or analyses may not be indicative of results that may be obtained in later trials or preclinical studies.

The results of preclinical studies, clinical trials, or analyses of the results from such trials may not be predictive of the results of later preclinical studies or clinical trials. Product candidates in later clinical trials may fail to show the desired safety and efficacy traits despite having progressed through preclinical studies and prior clinical trials or having shown promising results based on analyses of data from earlier trials. A number of companies in the pharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or adverse safety profiles, notwithstanding earlier promising results. Frequency’s FX-322 Phase 2b results (FX-322-208), for example, showed no statistically significant difference at day 90 between those administered FX-322 versus those receiving placebo in the proportion of individuals that demonstrated an improvement in speech perception. In addition, conclusions based on promising data from analyses of clinical results, such as the prospective and post hoc analysis of data from its Phase 1/2 clinical trial of FX-322 for the

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treatment of SNHL (FX-322-201), may be shown to be incorrect in subsequent clinical trials that have pre-specified end points or may not be considered adequate by regulatory authorities. Further, Frequency has in the past and may in the future abandon product candidates that Frequency initially advanced for development based on positive preclinical results due to unfavorable results from additional preclinical studies. For example, Frequency recently discontinued its FX-322 and FX-345 development programs after the results of the FX-322-208 clinical trial. Even if Frequency completes later clinical trials as planned, Frequency cannot be certain that its results will support the safety and efficacy requirements sufficient to obtain regulatory approval, and, as a result, its clinical development plans may be materially harmed.

Interim and preliminary “top-line” data from its clinical trials that Frequency announces or publishes from time to time may change as more subject data becomes available and are subject to audit and verification procedures that could result in material changes in the final data.

From time to time, Frequency may publicly disclose interim, top-line or preliminary data from its clinical trials, which is based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data related to the particular study or trial. Frequency also makes assumptions, estimations, calculations and conclusions as part of its analyses of data, and Frequency may not have received or had the opportunity to fully and carefully evaluate all data. As a result, the top-line or preliminary results that Frequency reports may differ from future results of the same studies, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated. Top-line or preliminary data also remain subject to audit and verification procedures that may result in the final data being materially different from the top-line or preliminary data Frequency previously published. As a result, top-line and preliminary data should be viewed with caution until the final data are available.

From time to time, Frequency may also disclose interim data from its preclinical studies and clinical trials. Interim data from clinical trials that Frequency may complete are subject to the risk that one or more of the clinical outcomes may materially change as subject enrollment continues and more subject data become available. Adverse differences between interim data and final data could significantly harm its business prospects. Further, disclosure of interim data by Frequency or by its competitors could result in volatility in the price of Frequency common stock.

Further, others, including regulatory agencies, may not accept or agree with Frequency’s assumptions, estimates, calculations, conclusions or analyses or may interpret or weigh the importance of data differently, which could impact the value of the particular program, the approvability or commercialization of the particular product candidate or product and its company in general. In addition, the information Frequency chooses to publicly disclose regarding a particular study or clinical trial is based on what is typically extensive information, and you or others may not agree with what Frequency determines is material or otherwise appropriate information to include in its disclosure.

If the interim, top-line or preliminary data that Frequency reports differ from actual results, or if others, including regulatory authorities, disagree with the conclusions reached, its ability to obtain approval for, and commercialize, its product candidates may be harmed, which could harm its business, operating results, prospects or financial condition.

Any of Frequency’s product candidates or component of a product candidate that Frequency develops or the administration thereof, may cause serious adverse events or undesirable side effects, which may halt their clinical development, delay or prevent marketing approval, or, if approved, require them to be taken off the market, include safety warnings, or otherwise limit their sales.

Serious adverse events or undesirable side effects caused by its product candidates or component of a product candidate Frequency develops could cause Frequency or regulatory authorities to interrupt, delay, or halt clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or other comparable foreign regulatory authorities. Results of any clinical trial Frequency conducts could reveal a high and unacceptable severity and prevalence of side effects.

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If unacceptable side effects arise in the development of any product candidate, Frequency, the FDA, or the IRBs or IECs at the institutions in which its studies are conducted, or the DSMB, if constituted for their clinical trials, could recommend a suspension or termination of their clinical trials, or the FDA or comparable foreign regulatory authorities could order Frequency to cease further development of or deny approval of a product candidate for any or all targeted indications. In addition, drug-related side effects could affect subject recruitment or the ability of enrolled subjects to complete a trial or result in potential product liability claims. These side effects also may not be appropriately recognized or managed by the treating medical staff. Frequency may have to train medical personnel regarding the proper administration protocol for their product candidates and to understand the side effect profiles for their clinical trials and upon any commercialization of any of their product candidates. Inadequate training in recognizing or managing the potential side effects of their product candidates could result in subject injury or death. Any of these occurrences may harm its business, financial condition, and prospects significantly.

Additionally, if any product candidates Frequency develops receives marketing approval, and Frequency or others later identify undesirable side effects caused by such products, a number of potentially significant negative consequences could result, including:

Any of these events could prevent Frequency from achieving or maintaining market acceptance of a product candidate, if approved, and could significantly harm its business, results of operations, and prospects.

Disruptions at the FDA and other government agencies caused by funding shortages, changes in the federal administration or global health concerns could hinder their ability to hire and retain key leadership and other personnel, or otherwise prevent new products and services from being developed or commercialized in a timely manner, which could negatively impact Frequency’s business.

The ability of the FDA to review and approve new products can be affected by a variety of factors, including government budget and funding levels, ability to hire and retain key personnel and accept the payment of user fees, and statutory, regulatory, and policy changes. Average review times at the agency have fluctuated in recent years as a result. In addition, government funding of other government agencies that fund research and development activities is subject to the political process, which is inherently fluid and unpredictable.

Disruptions at the FDA and other agencies may also slow the time necessary for new drugs to be reviewed or approved by necessary government agencies, which would adversely affect Frequency’s business. For example, over the last several years, the U.S. government has shut down several times and certain regulatory

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agencies, such as the FDA, have had to furlough critical employees and stop critical activities. If a prolonged government shutdown occurs or the FDA experiences other delays, it could significantly impact the ability of the FDA to timely review and process their regulatory submissions, which could have a material adverse effect on their business.

Separately, in response to the COVID-19 pandemic, the FDA postponed most inspections of foreign and domestic manufacturing facilities at various points. Even though the FDA has since resumed standard inspection operations of domestic facilities where feasible, the FDA has continued to monitor and implement changes to its inspectional activities to ensure the safety of their employees and those of the firms it regulates as it adapts to the evolving COVID-19 pandemic, and any resurgence of the virus or emergence of new variants may lead to further inspectional delays.

Regulatory authorities outside the United States may adopt similar restrictions or other policy measures in response to the COVID-19 pandemic or issue guidance materially affecting the conduct of clinical trials. If a prolonged government shutdown occurs, or if global health concerns continue to prevent the FDA or other regulatory authorities from conducting their regular inspections, reviews, or other regulatory activities, it could significantly impact the ability of the FDA to timely review and process its regulatory submissions, which could have a material adverse effect on its business. Further, in Frequency’s operations as a public company, future government shutdowns or delays could impact its ability to access the public markets and obtain necessary capital in order to properly capitalize and continue its operations.

Frequency may not be successful in its efforts to identify additional product candidates. Due to Frequency’s limited resources and access to capital, Frequency must prioritize development of certain product candidates, the choice of which may prove to be wrong and adversely affect its business.

Frequency may fail to identify viable new product candidates for clinical development for several reasons. If Frequency fails to identify additional potential product candidates, its business could be materially harmed.

Research programs to develop additional product candidates based on its PCA approach require substantial technical, financial, and human resources whether or not they are ultimately successful. Frequency’s research programs may initially show promise in identifying potential indications or product candidates, yet fail to yield results for clinical development for several reasons, including:

Because Frequency has limited financial and human resources, Frequency focuses on research programs and product candidates for a limited set of indications. As a result, Frequency may forego or delay pursuit of opportunities with other product candidates or for other indications that could have greater commercial potential or a greater likelihood of success. Frequency’s resource allocation decisions may cause Frequency to fail to capitalize on viable commercial products or profitable market opportunities.

Accordingly, there can be no assurance that Frequency will ever be able to identify additional therapeutic opportunities for its product candidates or to develop suitable potential product candidates through internal research programs, which could materially adversely affect its future growth and prospects. Frequency may focus its efforts and resources on potential product candidates or other potential programs that ultimately prove to be unsuccessful.

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Frequency has never obtained marketing approval for a product candidate and Frequency may be unable to obtain, or may be delayed in obtaining, marketing approval for any product candidate.

Frequency has never obtained marketing approval for a product candidate. It is possible that the FDA may refuse to accept for substantive review any NDAs that Frequency submits for its product candidates or may conclude after review of its data that Frequency’s applications are insufficient to obtain marketing approval of its product candidates. Frequency believes its approach of activating progenitor cells to treat conditions or diseases through cellular regeneration is novel and, as a result, the process for, and the outcome of, FDA approval is especially uncertain. If the FDA does not accept or approve its NDAs for its product candidates, it may require that Frequency conducts additional clinical, preclinical, or manufacturing validation studies and submit that data before it will reconsider its applications. Depending on the extent of these or any other FDA-required studies, approval of any NDA that Frequency submits may be delayed or may require Frequency to expend more resources than Frequency has available. It is also possible that additional studies, if performed and completed, may not be considered sufficient by the FDA to approve its NDAs.

Any delay in obtaining, or an inability to obtain, marketing approvals would prevent Frequency from commercializing its product candidates, generating revenues, and achieving and sustaining profitability. If any of these outcomes occur, Frequency may be forced to abandon its development efforts for its product candidates, which could significantly harm Frequency’s business.

Even if Frequency obtains FDA approval for a product candidate in the United States, Frequency may never obtain approval for or commercialize the product candidate in any other jurisdiction, which would limit its ability to realize its full market potential.

In order to market any product in a particular jurisdiction, Frequency or its collaborators must establish and comply with numerous and varying regulatory requirements regarding safety and efficacy on a country-by-country basis. Approval by the FDA in the United States does not ensure approval by comparable regulatory authorities in other countries or jurisdictions. However, the failure to obtain approval in one jurisdiction may negatively impact Frequency’s or its collaborators’ ability to obtain approval elsewhere. In addition, clinical trials conducted in one country may not be accepted by regulatory authorities in other countries, and regulatory approval in one country does not guarantee regulatory approval in any other country.

Approval processes vary among countries and can involve additional product testing and validation and additional administrative review periods. Seeking foreign regulatory approval could result in difficulties and increased costs for Frequency and require additional preclinical studies or clinical trials which could be costly and time- consuming. Regulatory requirements can vary widely from country to country and could delay or prevent the introduction of its products in those countries. Frequency does not have any product candidates approved for sale in any jurisdiction, including in international markets, and Frequency does not have experience in obtaining regulatory approval in international markets. If Frequency fails to comply with regulatory requirements in international markets or to obtain and maintain required approvals, or if regulatory approvals in international markets are delayed, its target market will be reduced and Frequency will be unable to realize the full market potential of any product Frequency develops.

Even if Frequency obtains regulatory approval for any product candidate, Frequency will still face extensive and ongoing regulatory requirements and obligations, which may result in significant additional expense, and any product candidates, if approved, may face future development and regulatory difficulties.

Any product candidate for which Frequency obtains marketing approval, along with the manufacturing processes, post-approval clinical data, labeling, packaging, distribution, adverse event reporting, storage, recordkeeping, export, import, and advertising and promotional activities for such product, among other things, will be subject to extensive and ongoing requirements of and review by the FDA and other regulatory authorities. These requirements include submissions of safety and other post-marketing information and reports,

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establishment registration and drug listing requirements, continued compliance with current Good Manufacturing Practice, or cGMP, requirements relating to manufacturing, quality control, quality assurance, and corresponding maintenance of records and documents, requirements regarding the distribution of samples to physicians and recordkeeping and Good Clinical Practice, or GCP, and requirements for any clinical trials that Frequency conducts post-approval.

Even if marketing approval of a product candidate is granted, the approval may be subject to limitations on the indicated uses for which the product candidate may be marketed or to the conditions of approval, including a requirement to implement a REMS. If a product candidate receives marketing approval, the accompanying label may limit the approved indicated use of the product, which could limit sales of the product. The FDA may also require costly post-marketing studies or clinical trials and surveillance to monitor the safety or efficacy of a product. The FDA closely regulates the post-approval marketing and promotion of drugs to ensure drugs are marketed only for the approved indications and in accordance with the provisions of the approved labeling. The FDA imposes stringent restrictions on manufacturers’ communications regarding off-label use, and if Frequency markets its products for uses beyond their approved indications, Frequency may be subject to enforcement action for off-label marketing. Violations of the Federal Food, Drug, and Cosmetic Act, or FDCA, relating to the promotion of prescription drugs, may lead to FDA enforcement actions and investigations alleging violations of federal and state healthcare fraud and abuse laws, as well as state consumer protection laws.

In addition, later discovery of previously unknown adverse events or other problems with its products, manufacturers, or manufacturing processes or failure to comply with regulatory requirements, may yield various results, including:

Further, the FDA’s policies may change, and additional government regulations may be enacted that could prevent, limit, or delay regulatory approval of a product candidate. If Frequency is slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if Frequency is not able to maintain regulatory compliance, Frequency may lose any marketing approval that it may have obtained, which would adversely affect its business, prospects, and ability to achieve or sustain profitability.

Frequency also cannot predict the likelihood, nature, or extent of government regulation that may arise from future legislation or administrative or executive action, either in the United States or abroad. The policies of the FDA and of other comparable regulatory authorities may change and additional government regulations may be enacted that could prevent, limit, or delay regulatory approval of a product candidate. If Frequency is slow or

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unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if Frequency is not able to maintain regulatory compliance, Frequency may be subject to enforcement action, and it may not achieve or sustain profitability, which would adversely affect its business, prospects, financial condition, and results of operations. Furthermore, noncompliance by Frequency or any collaborator with regulatory requirements, including safety monitoring or pharmacovigilance, may also result in significant financial penalties, which would adversely affect its business.

Potential product liability lawsuits against Frequency could cause Frequency to incur substantial liabilities and limit commercialization of any products that it may develop.

The use of any product candidate Frequency may develop in clinical trials and the sale of any products for which Frequency obtains marketing approval exposes Frequency to the risk of product liability claims. Product liability claims might be brought against Frequency by patients, healthcare providers, pharmaceutical companies or others selling or otherwise coming into contact with its products. On occasion, large judgments have been awarded in class action lawsuits based on drugs that had unanticipated adverse effects. If Frequency cannot successfully defend against product liability claims, it could incur substantial liability and costs. In addition, regardless of merit or eventual outcome, product liability claims may result in:

The product liability insurance Frequency currently carries, and any additional product liability insurance coverage Frequency acquires in the future, may not be sufficient to reimburse Frequency for any expenses or losses Frequency may suffer. Moreover, insurance coverage is becoming increasingly expensive and, in the future, Frequency may not be able to maintain insurance coverage at a reasonable cost or in sufficient amounts to protect Frequency against losses due to liability. If Frequency obtains marketing approval for any product candidate, Frequency intends to acquire insurance coverage to include the sale of commercial products; however, Frequency may be unable to obtain product liability insurance on commercially reasonable terms or in adequate amounts. A successful product liability claim, or series of claims, brought against Frequency could cause its share price to decline and, if judgments exceed its insurance coverage, could adversely affect its results of operation and business, including preventing or limiting the commercialization of any product candidates Frequency develops.

The COVID-19 pandemic has caused and could continue to cause disruptions to Frequency’s business, including its preclinical studies, clinical trials and operations and could adversely impact its financial condition and results of operations.

The global outbreak of COVID-19 continues to rapidly evolve and continues to have indeterminable adverse effects on general commercial activity and the world economy. Due to the uncertain nature of the effects of the outbreak, particularly in the United States, enrollment, participation and retention in Frequency’s planned trials may be reduced, and for a number of the clinical sites, halted for an unknown period of time. Any reduction in enrollment, participation and retention and any halts may delay clinical trials and development plans for any product candidates, which could have an adverse impact on Frequency’s business and results of operations.

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If COVID-19 or its variants again spread in the United States and worldwide, and measures to mitigate the ongoing effects of the pandemic, such as stay home orders and/or advisories persist or are reintroduced, Frequency may continue to experience disruptions and other effects on its business that could severely impact its business, operations, preclinical studies and clinical trials, including:

The extent to which COVID-19 may continue to impact Frequency’s business, preclinical studies, clinical trials and operations will depend on future developments, which are highly uncertain and cannot be predicted with confidence. In addition, if Frequency or any of the third parties with whom Frequency engages were to experience shutdowns or additional business disruptions, Frequency’s ability to conduct its business in the manner and on the timelines presently planned could be materially and negatively impacted, which could have a material adverse effect on its business and its financial results. The COVID-19 pandemic has resulted in a widespread health crisis that has adversely affected the economies and financial markets worldwide, resulting in an economic downturn that could continue to significantly impact its business, financial condition and results of operations. To the extent the COVID-19 pandemic adversely affects Frequency’s business, financial condition and results of operations, it may also have the effect of heightening many of the other risks described in this “Risk Factors” section.

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Risks related to commercialization

Frequency faces significant competition from biotechnology and pharmaceutical companies, and its operating results will suffer if Frequency fails to compete effectively.

The biotechnology and pharmaceutical industries are highly competitive and subject to significant and rapid technological change. Frequency’s success is highly dependent on its ability to acquire, develop, and obtain marketing approval for new products on a cost-effective basis and to market them successfully. If a product candidate Frequency develops is approved, Frequency will face intense competition from a variety of businesses, including large, fully integrated pharmaceutical companies, specialty pharmaceutical companies, and early-stage companies, particularly if the early-stage company has a collaborative arrangement with a large and established company. Frequency is aware of several companies developing programs with research and development efforts to treat MS through the regeneration of myelin.

Competition could render any product candidate Frequency develops obsolete, less competitive, or uneconomical. Frequency’s competitors may, among other things:

If Frequency is not able to effectively compete for any of the foregoing reasons, its business will be materially harmed.

The successful commercialization of any product candidate Frequency develops will depend in part on the extent to which governmental authorities and health insurers establish adequate coverage, reimbursement levels, and pricing policies. Failure to obtain or maintain coverage and adequate reimbursement for its product candidates, if approved, could limit Frequency’s or its collaborators’ ability to market those products and decrease Frequency’s or its collaborators’ ability to generate revenue.

The availability and adequacy of coverage and reimbursement by governmental healthcare programs such as Medicare and Medicaid, private health insurers, and other third-party payors are essential for most patients to be able to afford prescription medications. Frequency’s ability to achieve acceptable levels of coverage and reimbursement for products or procedures using its products by governmental authorities, private health insurers and other organizations will influence its ability to successfully commercialize any product candidates Frequency develops. Assuming Frequency obtains coverage for any product candidates or procedures using its products by a third-party payor, the resulting reimbursement payment rates may not be adequate or may require co-payments that patients find unacceptably high. Frequency cannot be sure that coverage and reimbursement in the United States or elsewhere will be available for any product Frequency commercializes, and any reimbursement that may become available may be decreased or eliminated in the future.

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Third-party payors increasingly are challenging prices charged for pharmaceutical products and services, and the current presidential administration and Congress have introduced several proposals related to drug pricing. Many third-party payors may refuse to provide coverage and reimbursement for particular drugs or biologics when an equivalent generic drug, biosimilar, or a less expensive therapy is available. A third-party payor may consider such a drug as substitutable and only offer to reimburse patients for the less expensive product. Even if Frequency shows improved efficacy, pricing of existing drugs may limit the amount Frequency will be able to charge for any product Frequency commercializes. Payors may deny or revoke the reimbursement status of a given product or establish prices for new or existing marketed products at levels that are too low to enable Frequency to realize a satisfactory return on its investment in its product candidates. If reimbursement is not available or is available only at limited levels, Frequency may not be able to successfully commercialize its product candidates and may not be able to obtain a satisfactory financial return on its product candidates. Additionally, Frequency’s ability to obtain a satisfactory financial return depends on what, if any, proposals related to drug pricing may be implemented and, if implemented, when they might take effect.

There is significant uncertainty related to the insurance coverage and reimbursement of newly approved products. In the United States, third-party payors, including private and governmental payors, such as the Medicare and Medicaid programs, play an important role in determining the extent to which new drugs and biologics will be covered. The Medicare and Medicaid programs increasingly are used as models in the United States for how private payors and other governmental payors develop their coverage and reimbursement policies for drugs and biologics. Some third-party payors may require pre-approval of coverage for new or innovative devices or drug therapies before they will reimburse healthcare providers who use such therapies. It is difficult to predict at this time what third-party payors will decide with respect to the coverage and reimbursement for its product candidates.

No uniform policy for coverage and reimbursement for products exists among third-party payors in the United States. Therefore, coverage and reimbursement for products can differ significantly from payor to payor, and one third-party payor’s decision to cover a product does not ensure that other payors will also provide similar coverage. Additionally, the process for determining whether a third-party payor will provide coverage for a product is typically separate from the process for setting the price of such product or establishing the reimbursement rate that the payor will pay for the product once coverage is approved. As a result, the determination of coverage and reimbursement is often a time-consuming and costly process that will require Frequency to provide scientific and clinical support for the use of Frequency’s product candidates to each payor separately, with no assurance that coverage and adequate reimbursement will be applied consistently or obtained in the first instance.

Furthermore, rules and regulations regarding reimbursement change frequently, in some cases at short notice, and Frequency believes that changes in these rules and regulations are likely.

Moreover, increasing efforts by governmental and third-party payors in the United States to cap or reduce healthcare costs may cause such organizations to limit both coverage and the level of reimbursement for newly approved products and, as a result, they may not cover or provide adequate payment for any product Frequency commercializes. Frequency expects to experience pricing pressures in connection with the sale of any product candidates due to the trend toward managed health care, the increasing influence of health maintenance organizations, and additional legislative, administrative, or regulatory changes. The downward pressure on healthcare costs in general, particularly prescription drugs and biologics and surgical procedures and other treatments, has become intense. As a result, increasingly high barriers are being erected to the entry of new products.

Frequency may also be subject to extensive governmental price controls and other market regulations outside of the United States, and Frequency believes the increasing emphasis on cost-containment initiatives in other countries have and will continue to put pressure on the pricing and usage of medical products. In many countries, the prices of medical products are subject to varying price control mechanisms as part of national

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health systems. Other countries allow companies to fix their own prices for medical products but monitor and control company profits. Additional foreign price controls or other changes in pricing regulation could restrict the amount that Frequency is able to charge for products Frequency commercializes. Accordingly, in markets outside the United States, the reimbursement for products Frequency or commercialize may be reduced compared with the United States and may be insufficient to generate commercially reasonable revenue and profits.

Even if a product candidate Frequency develops receives marketing approval, it may fail to achieve market acceptance by physicians, patients, third-party payors, or others in the medical community necessary for commercial success.

If a product candidate Frequency develops receives marketing approval, it may nonetheless fail to gain sufficient market acceptance by physicians, patients, third-party payors, and others in the medical community. In addition, physicians, patients, and third-party payors may prefer other novel products to Frequency’s. If a product candidate does not achieve an adequate level of acceptance, Frequency may not generate significant product revenues or become profitable. The degree of market acceptance of its product candidates, if approved, will depend on several factors, including, but not limited to:

Because Frequency expects sales of its product candidates, if approved, to generate substantially all its revenues for the foreseeable future, the failure of its product candidates to find market acceptance would harm its business and could require Frequency to seek additional financing.

If Frequency is unable to establish sales and marketing capabilities either on its own or in collaboration with third parties, Frequency may not be successful in commercializing any product candidate Frequency develops, if approved.

In order to market and successfully commercialize any product candidate Frequency develops, if approved, Frequency must build its sales and marketing capabilities or enter into collaborations with third parties for these services. Frequency currently has no sales, marketing or distribution capabilities and as a company have no experience in marketing products. To the extent that Frequency depends on collaborators for sales and marketing activities, any revenues Frequency receives will depend upon the success of those collaborators’ sales and marketing teams and the collaborators’ prioritization of its product and compliance with applicable regulatory requirements, and there can be no assurance that the collaborators’ efforts will be successful.

If Frequency is unable to enter into a collaboration for the commercialization of product candidates Frequency develops, if approved, Frequency may be forced to delay the commercialization of its product candidates or reduce the scope of its sales or marketing activities, which would have an adverse effect on its business, operating results and prospects.

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A variety of risks associated with operating internationally could materially adversely affect Frequency’s business.

Frequency’s business strategy includes potentially expanding internationally if any of its product candidates receive regulatory approval. Doing business internationally involves several risks, including, but not limited to:

Any of these factors could significantly harm any future international expansion and operations and, consequently, Frequency’s results of operations.

Risks related to Frequency’s dependence on third parties

Frequency may not succeed in establishing and maintaining collaborations, which may significantly limit its ability to successfully develop and commercialize any product candidates.

Frequency may seek collaborations for the development and commercialization of any product candidates. The process of establishing and maintaining collaborative relationships is difficult, time-consuming, and involves significant uncertainty, such as:

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If any collaborator fails to fulfill its responsibilities in a timely manner, or at all, Frequency’s research, clinical development, manufacturing, or commercialization efforts related to that collaboration could be delayed or terminated, or it may be necessary for Frequency to assume responsibility for expenses or activities that would otherwise have been the responsibility of its collaborator. If Frequency is unable to establish and maintain collaborations on acceptable terms or to successfully transition away from terminated collaborations, Frequency may have to delay or discontinue further development of one or more of its product candidates, undertake development and commercialization activities at its own expense, or find alternative sources of capital, which would have a material adverse impact on Frequency’s clinical development plans and business.

Frequency’s employees and independent contractors, including principal investigators, CROs, consultants, vendors, and any third parties Frequency may engage in connection with development and commercialization may engage in misconduct or other improper activities, including noncompliance with regulatory standards and requirements, which could have a material adverse effect on its business.

Frequency’s employees and independent contractors, including principal investigators, CROs, consultants, vendors, and any third parties Frequency may engage in connection with development and commercialization of its product candidates, could engage in misconduct, including intentional, reckless, or negligent conduct or unauthorized activities that violate applicable laws, rules, and regulations including: the laws and regulations of the FDA or other similar regulatory requirements of other authorities, including those laws that require the reporting of true, complete, and accurate information to such authorities; manufacturing standards; data privacy, security, fraud and abuse, and other healthcare laws and regulations; or laws that require the reporting of true, complete, and accurate financial information and data. Specifically, sales, marketing, and business arrangements in the healthcare industry are subject to extensive laws and regulations intended to prevent fraud, misconduct, kickbacks, self-dealing, and other abusive practices. These laws and regulations may restrict or prohibit a wide range of pricing, discounting, marketing and promotion, sales commission, customer incentive programs, and other business arrangements. Activities subject to these or other laws could also involve the improper use or misrepresentation of information obtained in the course of clinical trials, creation of fraudulent data in preclinical studies or clinical trials, or illegal misappropriation of drug product, which could result in regulatory sanctions and cause serious harm to Frequency’s reputation. It is not always possible to identify and deter misconduct by employees and other third parties, and the precautions Frequency takes to detect and prevent this activity may not be effective in controlling

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unknown or unmanaged risks or losses or in protecting Frequency from governmental investigations or other actions or lawsuits stemming from a failure to comply with such laws or regulations. Additionally, Frequency is subject to the risk that a person or government agency could allege such fraud or other misconduct, even if none occurred. If any such actions are instituted against Frequency or them and Frequency is not successful in defending itself or asserting its rights, those actions could have a significant impact on its business and results of operations, including the imposition of significant civil, criminal, and administrative penalties, damages, monetary fines, possible exclusion from participation in Medicare, Medicaid, other U.S. federal healthcare programs or healthcare programs in other jurisdictions, individual imprisonment, other sanctions, contractual damages, reputational harm, diminished profits and future earnings, and curtailment of its operations.

Frequency currently intends to rely on third-party CMOs for the production of clinical supply and the production of commercial supply of any product candidates, as well as to supply raw materials necessary to produce its product candidates. Frequency’s dependence on CMOs may impair the development of its product candidates and may impair their commercialization, which would adversely impact its business and financial position.

Frequency does not own facilities for manufacturing any product candidate. Instead, Frequency relies on and expects to continue to rely on CMOs for the supply of cGMP grade clinical trial materials of any product candidates Frequency develops and, in future, for commercial quantities. Reliance on CMOs may expose Frequency to more risk than if Frequency was to manufacture its product candidates itself. If any CMO Frequency engages is unable to provide sufficient supply of any product candidate Frequency develops, Frequency may be unable to arrange for an alternative supply or to do so on commercially reasonable terms or in a timely manner, which could delay any clinical trials, the commercial launch of its product candidates, if approved, or, regarding any commercial supply, result in a shortage in supply that could negatively impact its revenues.

The facilities used to manufacture any product candidates Frequency develops must be inspected by the FDA and comparable foreign regulatory authorities. While Frequency provides oversight of manufacturing activities, Frequency does not and will not control the execution of manufacturing activities by, and are or will be dependent on, its CMOs for compliance with cGMP requirements for the manufacture of any product candidates. As a result, Frequency is subject to the risk that any product candidates may have manufacturing defects that Frequency has limited ability to prevent. If a CMO cannot successfully manufacture material that conforms to its specifications and the regulatory requirements, Frequency will not be able to secure or maintain regulatory approval for the use of its product candidates in clinical trials, or for commercial distribution of any product candidates, if approved. Frequency has limited control over the ability of its CMOs to maintain adequate quality control, quality assurance, and qualified personnel, and Frequency was not involved in developing its CMOs’ policies and procedures.

If the FDA or comparable foreign regulatory authority finds deficiencies with or does not approve these facilities for the manufacture of Frequency’s product candidates or if it withdraws any such approval or finds deficiencies in the future, Frequency may need to find alternative manufacturing facilities, which would delay its development program and significantly impact its ability to develop, obtain regulatory approval for, or commercialize its product candidates, if approved. In addition, any failure to achieve and maintain compliance with laws, regulations, and standards related to manufacturing could subject Frequency to risks, including the risk that Frequency may have to suspend the manufacture of its product candidates, that obtained approvals could be revoked, and that the FDA or another governmental regulatory authority may take enforcement actions, including untitled letters, warning letters, seizures, injunctions, or product recalls. Furthermore, CMOs may breach existing agreements they have with Frequency because of factors beyond its control. They may also terminate or refuse to renew their agreement at a time that is costly or otherwise inconvenient for Frequency. If Frequency was unable to find an adequate CMO or another acceptable solution in time, its clinical trials could be delayed, or its commercial activities could be harmed.

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Frequency contracts for the supply of the active pharmaceutical ingredient, or API, and other raw material necessary to produce any product candidates Frequency develops. Supplies of API or other raw material could be interrupted from time to time and Frequency cannot be certain that alternative supplies could be obtained within a reasonable time frame, at an acceptable cost, or at all. The extent to which the COVID-19 pandemic impacts Frequency’s ability to procure sufficient supplies for the development of its products and product candidates will depend on the severity and duration of the spread of the virus, and the actions undertaken to mitigate the spread of COVID-19 or treat its effects and may cause delays. In addition, a disruption in the supply of API or other raw material could delay the commercial launch of its product candidates, if approved, or result in a shortage in supply, which would impair its ability to generate revenues. Growth in the costs and expenses of API or other raw material may also impair its ability to cost-effectively manufacture its product candidates. In addition, there may be a limited number of suppliers for API or other raw material that Frequency may use to manufacture its product candidates, and Frequency cannot be certain that Frequency will be able to engage such suppliers in a timely manner or at all. If Frequency is unable to do so, clinical development of its product candidates, commercialization for any approved product, or its business could be adversely affected.

Finding new CMOs or third-party suppliers involves additional cost and requires its management’s time and focus. In addition, there is typically a transition period when a new CMO commences work. Although Frequency has not, and does not intend to, begin a clinical trial unless Frequency believes it has on hand, or will be able to obtain, a sufficient supply of its product candidates to complete the clinical trial, any significant delay in the supply of its product candidates or the raw materials needed to produce its product candidates, could considerably delay conducting its clinical trials and potential regulatory approval of its product candidates.

As part of their manufacture of Frequency’s product candidates, its CMOs and third-party suppliers are expected to comply with and respect the proprietary rights of others. If a CMO or third-party supplier fails to acquire the proper licenses or otherwise infringes the proprietary rights of others in the course of providing services to Frequency, Frequency may have to find alternative CMOs or third-party suppliers or defend against claims of infringement, either of which would significantly impact its ability to develop, obtain regulatory approval for, or commercialize its product candidates, if approved.

Frequency intends to rely on third parties to conduct, supervise, and monitor its clinical trials. If those third parties do not successfully carry out their contractual duties, or if they perform in an unsatisfactory manner, it may harm its business.