SEC Form 425 filed by Passage Bio Inc.

7/21/26 9:40:53 PM ET

$PASG

Biotechnology: Biological Products (No Diagnostic Substances)

Health Care

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425 1 ny20077915x2_425.htm 425

Filed by Passage Bio, Inc.

pursuant to Rule 425 under the Securities Act of 1933

and deemed filed pursuant to Rule 14a-12

under the Securities Exchange Act of 1934

Subject Company: Passage Bio, Inc.

Filer’s SEC File No.: 001-39231

Date: July 21, 2026

This filing relates to the proposed merger of Remix Therapeutics, Inc., a Delaware corporation (“Remix”), with Merger Sub, Inc. (“Merger Sub”), a Delaware corporation and wholly owned subsidiary of Passage Bio, Inc., a Delaware corporation (“Passage Bio”), pursuant to the terms of that certain Agreement and Plan of Merger and Reorganization, dated as of June 24, 2026, by and among Remix, Merger Sub and Passage Bio. The following is a copy of the corporate presentation prepared by Remix, dated July 21, 2026:

Cautionary Statement Regarding Forward-Looking Statements

This communication contains forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995, including statements regarding the proposed transaction involving Passage Bio and Remix, including the conditions to, and timing of, closing of the proposed transaction, the Board of Directors and management of the combined company, the percentage ownership of the combined company (which is subject to adjustment based on the amount of Passage Bio’s net cash as of the closing of the proposed transaction), and the parties’ ability to consummate the proposed transaction and private placement financing, including the intended use of net proceeds from the private placement financing and the expected timing of closing and completion of the private placement financing, the expected issuance of the CVR and the contingent payments contemplated by the CVR, the combined company’s expected cash and the sufficiency of the combined company’s cash to fund operations into 2028, the listing of the combined company’s shares on Nasdaq, the expectations surrounding the potential, safety, efficacy, and regulatory and clinical progress of Remix’s product candidates, including REM-422, and anticipated milestones and timing, among others.

Forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as “may,” “will,” “should,” “would,” “expect,” “anticipate,” “plan,” “likely,” “believe,” “estimate,” “project,” “intend,” and other similar expressions among others. Statements that are not historical facts are forward-looking statements. Forward-looking statements are based on current beliefs and assumptions that are subject to risks and uncertainties and are not guarantees of future performance. Actual results could differ materially from those contained in any forward-looking statement as a result of various factors, including, without limitation: (i) the risk that the conditions to the closing of the proposed transaction are not satisfied, including the failure to timely or at all obtain stockholder approval for the proposed transaction or the failure to timely or at all obtain any required regulatory clearances; (ii) uncertainties as to the timing of the consummation of the proposed transaction and the ability of each of Passage Bio and Remix to consummate the proposed transaction; (iii) the ability of Passage Bio and Remix to integrate their businesses successfully and to achieve anticipated synergies; (iv) the possibility that other anticipated benefits of the proposed transaction will not be realized, including without limitation, anticipated revenues, expenses, earnings and other financial results, and growth and expansion of the combined company’s operations, and the anticipated tax treatment of the combination; (v) potential litigation relating to the proposed transaction that could be instituted against Passage Bio, Remix or their respective directors; (vi) possible disruptions from the proposed transaction that could harm Passage Bio’s and/or Remix’s respective businesses; (vii) the ability of Remix to retain, attract and hire key personnel; (viii) potential adverse reactions or changes to relationships with employees, suppliers or other parties resulting from the announcement or completion of the proposed transaction; (ix) potential business uncertainty, including changes to existing business relationships, during the pendency of the proposed transaction that could affect Passage Bio’s or Remix’s financial performance; (x) certain restrictions during the pendency of the proposed transaction that may impact Passage Bio’s or Remix’s ability to pursue certain business opportunities or strategic transactions; (xi) the combined company’s need for additional funding, which may not be available; (xii) failure to identify additional product candidates and develop or commercialize marketable products; (xiii) the early stage of the combined company’s development efforts; (xiv) potential unforeseen events during clinical trials could cause delays or other adverse consequences; (xv) risks relating to the regulatory approval process; (xvi) interim, topline and preliminary data may change as more patient data become available, and are subject to audit and verification procedures that could result in material changes in the final data; (xvii) Passage Bio’s and Remix’s product candidates may cause serious adverse side effects; (xviii) inability to maintain collaborations, or the failure of these collaborations; (xix) the combined company’s reliance on third parties, including for the manufacture of materials for our research programs, preclinical and clinical studies; (xx) failure to obtain U.S. or international marketing approval; (xxi) ongoing regulatory obligations; effects of significant competition; (xxii) unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives; (xxiii) product liability lawsuits; (xxiv) securities class action litigation; (xxv) the impact of general economic conditions on our business and operations, including the combined company’s preclinical studies and clinical trials; (xxvi) the possibility of system failures or security breaches; risks relating to intellectual property; (xxvii) significant costs incurred as a result of operating as a public company; (xxviii) the risk that, as a result of adjustments to the exchange ratio, Passage Bio stockholders and Remix stockholders could own more or less of the combined company than is currently anticipated, including as a result of the determination of Passage Bio’s net cash; (xxix) risks related to the market price of Passage Bio’s common stock relative to the value implied by the exchange ratio; (xxx) the risk that holders of the CVR may never receive any payments thereunder; (xxxi) the risk that the concurrent private placement financing is not consummated; and (xxxii) such other factors as are set forth in Passage Bio’s periodic public filings with the SEC, including but not limited to those described under the heading “Risk Factors” in Passage Bio’s Annual Report on Form 10-K for the year ended December 31, 2025 and Quarterly Report on Form 10-Q for the period ended March 31, 2026. Passage Bio and Remix can give no assurance that the conditions to the proposed transaction will be satisfied. Except as required by applicable law, Passage Bio and Remix undertake no obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise.

Additional Information and Where to Find It

This communication relates to a proposed transaction involving Passage Bio and Remix and may be deemed to be solicitation material in respect of the proposed transaction. In connection with the proposed transaction, Passage Bio intends to file with the Securities and Exchange Commission (the “SEC”) a registration statement on Form S-4 that will contain a proxy statement of Passage Bio that will constitute a prospectus with respect to shares of Passage Bio stock to be issued in the proposed transaction (the “Proxy Statement/Prospectus”). Passage Bio may also file other documents with the SEC regarding the proposed transaction. This document is not a substitute for the Proxy Statement/Prospectus or any other document which Passage Bio may file with the SEC. INVESTORS AND SECURITYHOLDERS OF PASSAGE BIO AND REMIX ARE URGED TO READ THE PROXY STATEMENT/PROSPECTUS AND ANY OTHER RELEVANT DOCUMENTS THAT WILL BE FILED BY PASSAGE BIO WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION AND RELATED MATTERS. Passage Bio and Remix stockholders will also be able to obtain free copies of the Proxy Statement/Prospectus (when available) and other documents containing important information about Passage Bio, Remix and the proposed transaction that will be filed with the SEC by Passage Bio through the website maintained by the SEC at www.sec.gov. Copies of the documents filed with the SEC by Passage Bio will also be available free of charge on Passage Bio’s website at www.passagebio.com or by contacting Passage Bio’s investor relations department by email at investors@passagebio.com.

No Offer or Solicitation

This communication does not constitute an offer to sell or the solicitation of an offer to buy any securities nor a solicitation of any vote or approval with respect to the proposed transaction. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the U.S. Securities Act of 1933, as amended, and otherwise in accordance with applicable law.

Participants in the Solicitation

Passage Bio, Remix and their respective directors and executive officers may be deemed to be “participants” (as defined in Section 14(a) of the Securities Exchange Act of 1934) in the solicitation of proxies from Passage Bio’s stockholders in connection with the proposed transaction. Information regarding the persons who may, under SEC rules, be deemed participants in the solicitation of proxies from Passage Bio’s stockholders in connection with the proposed transaction will be set forth in the Proxy Statement/Prospectus on Form S-4 for the proposed transaction, which is expected to be filed with the SEC by Passage Bio. Information regarding Passage Bio’s directors and executive officers is also available in Passage Bio’s most recent Annual Report on Form 10-K and in its definitive proxy statement for its 2026 annual meeting of stockholders filed with the SEC on April 7, 2026. Investors and securityholders of Passage Bio and Remix are urged to read the Proxy Statement/Prospectus and other relevant documents that will be filed with the SEC by Passage Bio carefully and in their entirety when they become available because they will contain important information about the proposed transaction.

Modulating RNA Processing TO TARGET THE UNDRUGGABLEInvestor Presentation July 2026 Filed by Passage Bio, Inc. pursuant to Rule 425 under the Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 under the Securities Exchange Act of 1934 Subject Company: Passage Bio, Inc. Filer’s SEC File No.: 001-39231 Date: July 21, 2026

Disclaimers Important Information for Investors This confidential presentation (“Presentation”) is for informational purposes only and is being provided to interested parties solely in their capacity as potential investors for the purpose of evaluating a potential private offering of securities (the “Purpose”) by Remix Therapeutics, Inc. (collectively with its subsidiaries, “Remix”), in connection with a potential business combination between Passage Bio, Inc. (collectively with its subsidiaries, “Passage”) and Remix (the “Proposed Transaction”). By accepting this Presentation, you acknowledge and agree that all of the information contained herein is confidential, that you will use such information only for the Purpose and that you shall not use such information in any way that is detrimental to Remix or Passage. The information contained herein does not purport to be all-inclusive and neither Remix, Passage, nor any of their respective affiliates or respective control persons, officers, directors, employees or representatives makes any representation or warranty, express or implied, as to the accuracy, completeness or reliability of the information contained in this Presentation. You should consult your own counsel and tax and financial advisors as to legal and related matters concerning the matters described herein, and, by accepting this Presentation, you confirm that you are not relying upon the information contained herein to make any investment or other decision. Furthermore, by accepting this presentation you will be deemed to represent that you are an accredited investor, have the capacity to protect your own interests in connection with the offering and have sufficient knowledge and experience in investing in investments similar to the securities to properly evaluate the merits and risks of the investment in the securities. This Presentation has been prepared by Remix. While Remix believes that the financial and other information contained herein is accurate, Remix expressly disclaims any and all liability for the contents of, or omissions from, this Presentation and for any other written or oral communication transmitted or made available to a recipient. This Presentation includes certain statements and estimates provided by Remix with respect to Remix's historical and anticipated performance as well as Remix's relative position within its market and industry. Such statements and estimates reflect various assumptions by Remix (some of which may not be stated) that may or may not prove to be accurate. Remix nor its affiliates or employees, directors, officers, contractors, advisors, members, successors, representatives or agents makes any representations or warranties (express or implied) concerning the accuracy or completeness of this Presentation, nor shall they have any liability for any representations or warranties (expressed or implied) contained in, or for any omissions from or errors in, this Presentation or any other written or oral communications transmitted to the recipient in the course of its evaluation of Remix and/or the Proposed Transaction. Only those particular representations and warranties that may be made in a definitive agreement when, as and if one is executed, and subject to such limitations and restrictions as may be specified in such definitive agreement, shall have any legal effect. The projections and estimates of Remix's financial and operating performance throughout this Presentation have been provided to assist parties who may be interested in the Proposed Transaction but are not to be viewed as facts and should not be relied upon as a representation of future results. The assumptions underlying the estimates and projections contained herein are subject to significant economic and competitive uncertainties and contingencies beyond Remix's control. Also, judgments based upon past performance may not be necessarily indicative of future performance or industry trends. Consequently, no assurances are made or implied as to the reliability of such projections or estimates and the inclusion of the projections and estimates herein should not be regarded as a representation that the projected results will be achieved. No independent accounting firm has examined or reviewed the financial estimates or projections contained herein, and accordingly, no conclusion or any form of assurance with respect thereto is provided. Certain information contained in this Presentation relates to or is based on studies, publications, surveys and Remix's own internal estimates and research. In this Presentation, Remix relies on, and refers to, publicly available information and statistics regarding market participants in the sector in which Remix competes and other industry data. Any comparison of Remix to any other entity assumes the reliability of the information available to Remix. Remix obtained this information and statistics from third-party sources, including reports by market research firms and company filings. In addition, all of the market data included in this Presentation involve a number of assumptions and limitations, and there can be no guarantee as to the accuracy or reliability of such assumptions. Finally, while Remix believes its internal research is reliable, such research has not been verified by any independent source and Remix has not independently verified the information. This Presentation and the information contained herein shall be subject to the terms of the Confidentiality and Non-Disclosure Agreement previously executed by the recipient. The recipient agrees not to use or disclose to any person any information contained in this Presentation, the fact that it obtained confidential information concerning Remix, the fact that discussions or negotiations are taking place, or have taken place, concerning the Proposed Transaction involving Remix, or any of the other terms, conditions or other facts with respect to any such possible transaction. In furnishing this Presentation, neither Remix nor Passage undertakes an obligation to provide the recipient with access to any additional information or to update or correct any information provided. This Presentation shall not be deemed an indication of the state of affairs of Remix nor shall it constitute an indication that there has been no change in the business or affairs of Remix since the date hereof. Remix and Passage expressly reserve the right, without giving reason, at any time and in any respect, to terminate discussions with any or all parties, to reject any or all proposals and to negotiate with any party with respect to the Proposed Transaction. No person is authorized to give any information not contained in this Presentation. No other information has been authorized by Remix to be provided other than the information contained herein. Any information not contained herein must not be relied upon as having been authorized by Remix. Except as otherwise indicated, this Presentation reflects information made available as of the date on the cover page of this summary. Neither the delivery of this Presentation nor any transaction made hereunder shall, under any circumstances, create the implication that there has been no change in the affairs of Remix since the respective dates at which the information is given herein or the date hereof. The information contained in this Presentation should not be assumed to have been updated at any time subsequent to the date shown on the first page of this Presentation and the delivery of this Presentation does not constitute a representation by any person that such information will be updated at any time after the date of this Presentation. Private Placement This Presentation does not constitute an offer to sell or the solicitation of an offer to buy any securities of Remix or Passage, nor does it constitute an offer to sell or a solicitation of an offer to buy any securities from any person in any state or other jurisdiction in which such offer or solicitation would be unlawful. Furthermore, nothing contained in this Presentation shall be deemed to be a recommendation to buy or sell securities of Remix or Passage, nor shall it be relied upon to make personal investment decisions. Recipients of this Presentation should not construe the contents hereof to constitute legal, tax, regulatory, financial, accounting or other advice. Any recipient of this Presentation should seek advice from its own independent tax advisor, legal counsel and/or other advisor with respect to such matters. ANY SECURITIES TO BE OFFERED IN ANY TRANSACTION CONTEMPLATED HEREBY HAVE NOT BEEN AND WILL NOT BE REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), OR ANY APPLICABLE STATE OR FOREIGN SECURITIES LAW. ANY SECURITIES TO BE OFFERED IN ANY TRANSACTION CONTEMPLATED HEREBY HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE UNITED STATES SECURITIES AND EXCHANGE COMMISSION (THE “SEC”), ANY STATE SECURITIES COMMISSION OR OTHER UNITED STATES OR FOREIGN REGULATORY AUTHORITY, AND WILL BE OFFERED AND SOLD SOLELY IN RELIANCE ON AN EXEMPTION FROM THE REGISTRATION REQUIREMENTS PROVIDED BY THE SECURITIES ACT AND THE RULES AND REGULATIONS PROMULGATED THEREUNDER (INCLUDING REGULATION D OR REGULATION S UNDER THE SECURITIES ACT). THIS DOCUMENT DOES NOT CONSTITUTE, OR FORM A PART OF, AN OFFER TO SELL OR THE SOLICITATION OF AN OFFER TO BUY IN ANY STATE OR OTHER JURISDICTION TO ANY PERSON TO WHOM IT IS UNLAWFUL TO MAKE SUCH OFFER OR SOLICITATION. Forward-Looking Statements Certain statements in this Presentation may constitute “forward-looking statements.” Forward-looking statements include, but are not limited to, statements regarding Remix's expectations, hopes, beliefs, intentions or strategies regarding the future including, without limitation, statements regarding: Remix's RNA processing platform and product candidates, including the safety or efficacy of REM-422; Remix's clinical trials in adenoid cystic carcinoma (“ACC”), acute myelogenous leukemia (“AML”) & high-risk myelodysplastic syndrome (“HR-MDS”), including the timing of regulatory filings and data readouts and other developments or results in connection therewith; expected interactions or filings with regulators, including the Food & Drug Administration (“FDA”) and European Medicines Agency (“EMA”); the market opportunity, potential for combination therapies or other potential indications for REM-422; the expected timing of commercialization of any of its product candidates, including REM-422; the potential of Remix's discovery programs, including RXSM-1244 or other programs targeting MYC-dependent cancers and related pre-clinical studies; Remix's expected cash runway; Remix's collaborations with third parties; and the Proposed Transaction, including any information with respect to the combined company and any anticipated benefits from the Proposed Transaction. In addition, any statements that refer to projections, forecasts, or other characterizations of future events or circumstances, including any underlying assumptions, are forward-looking statements. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “might,” “plan,” “possible,” “potential,” “predict,” “project,” “should,” “strive,” “would,” “aim,” “target,” “commit,” and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. Forward-looking statements are based on current expectations and assumptions that, while considered reasonable, are inherently uncertain. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. Risks and uncertainties that may cause actual results to differ materially from current expectations include, but are not limited to: uncertainties inherent in preclinical studies and clinical trials; risks and uncertainties regarding whether results from preclinical studies and clinical trials will be predictive of the results of future trials; risks related to the expected timing of submissions to regulatory authorities and timing for review by such regulatory authorities; risks and uncertainties related to collaborations with third parties; competition; the risk that Remix may not be able to execute on its business plans and strategies; risks and uncertainties related to the Proposed Transaction, including the risk that the Proposed Transaction may not be consummated on the anticipated terms or at all; the risk that the parties' expectations with respect to the benefits of the Proposed Transaction and the combined company may not be realized; and risks related to market volatility and global economic conditions. Nothing in this Presentation should be regarded as a representation by any person that the forward-looking statements set forth herein will be achieved or that any of the contemplated results of such forward-looking statements will be achieved. You should not place undue reliance on forward-looking statements in this Presentation, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Neither Remix nor Passage undertakes or accepts any duty to release publicly any updates or revisions to any forward-looking statements to reflect any change in its expectations or in the events, conditions or circumstances on which any such statement is based. This Presentation does not purport to summarize all of the conditions, risks and other attributes of an investment in Remix, Passage or the combined company or otherwise with respect to the Proposed Transaction. Trademarks This Presentation may contain trademarks, service marks, trade names and copyrights of other companies, which are the property of their respective owners. Solely for convenience, some of the trademarks, service marks, trade names and copyrights referred to in this Presentation may be listed without the TM, SM, © or ® symbols, but Remix and Passage will assert, to the fullest extent under applicable law, the rights of the applicable owners, if any, to these trademarks, service marks, trade names and copyrights. Confidentiality Notice This Presentation is intended exclusively for the individual or entity to which it is addressed. This Presentation and the accompanying communication may contain information that is proprietary, privileged, confidential or otherwise legally exempt from disclosure. If you are not an intended recipient, you are not authorized to read, print, retain, copy or disseminate this Presentation or any part of it. If you have received this Presentation in error, please notify the sender immediately and delete all copies of this Presentation. Parties who do not wish to pursue this matter, or upon the request of Remix or Passage, shall promptly return all material received from Remix and/or Passage including this Presentation and other material received in the course of investigation. NONE OF REMIX, PASSAGE, OR ANY OF THEIR CUSTOMERS, VENDORS, OR PARTNERS SHOULD BE CONTACTED DIRECTLY UNDER ANY CIRCUMSTANCE.

Risk Factors Risk Factors Both Remix and Passage are subject to various risks associated with their businesses and their industries. In addition, the Proposed Transaction, including the possibility that the Proposed Transaction may not be completed, poses a number of risks to each company and its respective securityholders. All references to “we,” “us” or “our” refer to the businesses of Remix and Passage prior to the consummation of the Proposed Transaction. The risks described below make up a non-exhaustive list of the key risks related to Remix and Passage’s businesses and the factors that could cause actual results to differ from the forward-looking statements described in this Presentation. This list has been prepared solely for potential private placement investors in connection with the Proposed Transaction and not for any other purpose. You should carefully consider these risks and uncertainties, as well as other risks set forth in the section entitled “Risk Factors” in Passage's most recent quarterly report on Form 10-Q, its most recent annual report on Form 10-K and its other SEC filings. You should also carry out your own due diligence and consult with your own financial and legal advisors concerning the risks and suitability of an investment in this private placement transaction before making an investment decision. The list below is qualified in its entirety by disclosures contained in future documents filed or furnished in respect of the Proposed Transaction with the SEC: Our limited operating history makes it difficult to evaluate our future prospects and the risks and challenges we may encounter. We have incurred significant losses since inception, we have not generated any revenue from product sales to date and may never do so. REM-422, our lead product candidate, is currently in clinical development and has not received regulatory approval. There is no assurance that our clinical trials will be successful or that we will obtain regulatory approval for REM-422 or any other product candidate on the timelines we expect, or at all. Our clinical trials of REM-422 in ACC and AML/HR-MDS, as well as our other product candidates, may not demonstrate sufficient safety and efficacy to obtain regulatory approval. We may be unable to advance product candidates through clinical development, or commercialize them if approved, and we may experience significant delays in doing so. Our expectations regarding a Breakthrough Therapy Designation filing for REM-422 and EMA interactions are subject to regulatory uncertainty, and there can be no assurance that such designations or favorable outcomes will be obtained. Our current or future product candidates may cause adverse or other undesirable side effects that could delay or prevent their regulatory approval, limit the commercial profile of an approved label, or result in significant negative consequences following marketing approval, if any. Even if the Proposed Transaction and the proposed private placement transaction are successful, we will require substantial additional capital to finance our operations in the future. If we are unable to raise such capital when needed, or on acceptable terms, we may be forced to delay, reduce or eliminate our development and pre-clinical programs, current or future clinical trials or future commercialization efforts. Our expectations regarding our cash runway and ability to reach data inflection points are based on numerous assumptions that may prove to be untrue; we may be required to raise capital sooner than anticipated and our exposure to certain contingent liabilities and contractual obligations may be greater than anticipated. We operate in intensely competitive markets that include companies with greater financial, technical and marketing resources than us. Competitive products may impair our product candidates’ development or limit their commercial potential. We depend on collaborations with third parties, including Roche Holding AG, and there can be no assurance that our collaborators will fulfill their obligations, that our collaborations will yield the anticipated milestone payments or royalties, or that these collaborations will not be terminated. Failure to manage our growth effectively could cause our business to suffer and have a material adverse effect on our ability to execute our business strategy, as well as operating results and financial condition. As our costs increase, we may experience fluctuations in our operating results, which could make our future operating results difficult to predict or cause operating results to fall below analysts’ and investors’ expectations. Our RNA processing discovery programs, including our MYC-targeting program, are at early stages of development and may not result in product candidates that can be advanced into clinical trials or ultimately receive regulatory approval. The biomarker-based patient selection strategy for REM-422 in ACC is based on preliminary clinical observations, and there can be no assurance that this approach will be validated in confirmatory studies or accepted by regulatory authorities for product labeling. If we are unable to obtain and maintain patent and other intellectual property protection for our technology and product candidates, or if the scope of the intellectual property protection obtained is not sufficiently broad, our competitors could develop and commercialize technology and product candidates similar or identical to ours, and our ability to successfully commercialize our technology and/or product candidates may be impaired. We may be subject to intellectual property rights claims by third parties, which are costly to defend, could require us to pay significant damages and may disrupt our business and operations. We are party to license agreements and collaboration agreements with third parties pursuant to which we obtained or granted rights to certain intellectual property; termination of these agreements or the failure to comply with obligations thereunder could materially harm our business. The conditions to complete the Proposed Transaction may not be satisfied, we may not realize the expected benefits of the Proposed Transaction, or we may uncover liabilities following the consummation of the Proposed Transaction that we had not anticipated. The shares acquired in the proposed private placement transaction will be subject to registration with the SEC, and upon registration, the share price may be volatile due to a variety of factors, such as changes in the competitive environment in which we operate, the regulatory framework of the industry in which we will operate, developments in our business and operations and changes in our capital structure.

Additional Disclaimers Additional Information and Where to Find It This presentation relates to a proposed transaction involving Passage Bio and Remix and may be deemed to be solicitation material in respect of the proposed transaction. In connection with the proposed transaction, Passage Bio intends to file with the Securities and Exchange Commission (the “SEC”) a registration statement on Form S-4 that will contain a proxy statement of Passage Bio that will constitute a prospectus with respect to shares of Passage Bio stock to be issued in the proposed transaction (the “Proxy Statement/Prospectus”). Passage Bio may also file other documents with the SEC regarding the proposed transaction. This document is not a substitute for the Proxy Statement/Prospectus or any other document which Passage Bio may file with the SEC. INVESTORS AND SECURITYHOLDERS OF PASSAGE BIO AND REMIX ARE URGED TO READ THE PROXY STATEMENT/PROSPECTUS AND ANY OTHER RELEVANT DOCUMENTS THAT WILL BE FILED BY PASSAGE BIO WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION AND RELATED MATTERS. Passage Bio and Remix stockholders will also be able to obtain free copies of the Proxy Statement/Prospectus (when available) and other documents containing important information about Passage Bio, Remix and the proposed transaction that will be filed with the SEC by Passage Bio through the website maintained by the SEC at www.sec.gov. Copies of the documents filed with the SEC by Passage Bio will also be available free of charge on Passage Bio’s website at www.passagebio.com or by contacting Passage Bio’s investor relations department by email at investors@passagebio.com. No Offer or Solicitation This presentation does not constitute an offer to sell or the solicitation of an offer to buy any securities nor a solicitation of any vote or approval with respect to the proposed transaction. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the U.S. Securities Act of 1933, as amended, and otherwise in accordance with applicable law. Participants in the Solicitation Passage Bio, Remix and their respective directors and executive officers may be deemed to be “participants” (as defined in Section 14(a) of the Securities Exchange Act of 1934) in the solicitation of proxies from Passage Bio’s stockholders in connection with the proposed transaction. Information regarding the persons who may, under SEC rules, be deemed participants in the solicitation of proxies from Passage Bio’s stockholders in connection with the proposed transaction will be set forth in the Proxy Statement/Prospectus on Form S-4 for the proposed transaction, which is expected to be filed with the SEC by Passage Bio. Information regarding Passage Bio’s directors and executive officers is also available in Passage Bio’s most recent Annual Report on Form 10-K and in its definitive proxy statement for its 2026 annual meeting of stockholders filed with the SEC on April 7, 2026. Investors and securityholders of Passage Bio and Remix are urged to read the Proxy Statement/Prospectus and other relevant documents that will be filed with the SEC by Passage Bio carefully and in their entirety when they become available because they will contain important information about the proposed transaction.

Merger of Remix Therapeutics and Passage Bio Overview Transaction Summary Management and Board Remix, a clinical-stage biotechnology company developing novel small molecule therapies designed to reprogram RNA processing and address disease drivers at their origin intends to merge with Passage Bio, Inc (Nasdaq: PASG) Passage exploration of strategic alternatives initiated in April 2026, evaluating several potential candidates Supported by the Board of Directors of both companies and subject to stockholder approval and other customary closing conditions Combined company will focus on advancing the development of Remix programs and targets Merger expected to close H2 26 Pro forma ownership: 92.6% Remix and 7.4% Passage, after giving effect to Remix concurrent financing Combined company will be well capitalized, including an oversubscribed $100M concurrent financing and Passage’s anticipated cash at the closing of the merger Funded into H1'28, past mid-2027 ACC data and potential NDA submission as early as H2'27 Remix management will operate pro forma company Board of Directors of combined company to be comprised of nine members, all of whom will be designated by Remix

REM-422: A De-Risked Oncology Asset at a Critical Inflection Point REM-422: The first drug candidate observed to inhibit MYB with meaningful clinical activity in ACC Adenoid Cystic Carcinoma (ACC): >1,500 US incidence and 13-15K US prevalence MYB driven cancer with no FDA approved treatments REM-422 Phase 1: durable 43% ORR* in MYB biomarker+ patients, exceeding historic benchmarks1,2,3 FDA authorized Remix to proceed with an ongoing Phase 2 study with proposed key elements, including: recommended dose, biomarker positive population, and single arm study design for potential registration Potentially registrational Phase 2 study in recurrent, metastatic or unresectable ACC ongoing with >60% enrolled, full enrollment expected H2’26 $600M+ US sales opportunity; Remix is preparing for potential commercial readiness in 2028 r/r AML and high risk MDS (HR-MDS): ~25,000 treatable AML/HR-MDS patients in the US REM-422 Ph1 dose escalation ongoing with multiple responses observed Funded through ACC Phase 2 readout and potential NDA submission as early as H2'27 ¹Tchekmedyian et al., ²J Clin Oncol. 2019, Locati et al., Cancer, 2020, ³ Laurie SA et al., Lancet Oncol 2011, *based on best overall response

Experienced management team with deep domain expertise PETE SMITH Co-Founder, President & CEO H3 Biomedicine, Takeda, Millennium HEATHER WASSERMAN Chief Business / Operating Officer Eli Lilly, Human Genome Sciences MYTHILI KONERU Chief Medical Officer Legend, Marker, Eli Lilly DOM REYNOLDS Chief Scientific Officer H3 Biomedicine, Forma, Millennium Matt Patterson Chair Kevin Bitterman, PhD Atlas Ventures Jeff Goater The Column Group Pete Smith, PhD Remix CEO Maria Koehler, MD Independent Scott Biller, PhD Independent Linda Bain Independent

Small molecule pipeline targeting high value oncology targets Target/Compound Mechanism Indications Discovery Pre-Clinical Clinical Rights Anticipated Milestone MYB/REM-422 mRNA degrader Adenoid Cystic Carcinoma ORR / DoR Data Mid ’27 MYB AML/MDS RP2D Data Mid '27 Others (e.g. BRCA, lymphoma, CRC) Oncology program mRNA degrader MYC-dependent cancers (~25% of all cancers) Additional Targets Degradation Oncology and CNS Additional Targets Degradation Multiple Therapeutic Areas Not disclosed

REM-422 offers compelling value proposition in ACC High unmet need in ACC, with no FDA-approved treatments Therapeutic candidate designed to target molecular driver of ACC Favorable clinical results: Robust results – 43% ORR* at RP2D, 100% disease control rate Historical controls for ORR range 0-15%, mPFS~7m Long durability with patients on therapy for up to 2 years and ongoing (mDOR not reached) Established biomarker selection with companion diagnostic in development Generally well-tolerated with no DLTs Oral, once daily dosing Remix is preparing for potential commercial readiness in 2028: Pursuing regulatory approval for recurrent, metastatic or unresectable ACC based on Ph2 single-arm study Potentially registrational Phase 2 study ongoing, >60% on study with full enrollment anticipated H2'26 REM-422: $600M+ U.S. opportunity with potential meaningful upside *based on best overall response

Adenoid Cystic Carcinoma has a high unmet medical need Malignant epithelial tumor arising predominantly in salivary glands and other glandular tissues; high rates of perineural invasion and relentless growth/metastasis 1,500+ new patients¹ per year in the US; prevalence is ~13K – 15K² MYB a key driver of disease in all subtypes, with 60-65% of ACC population MYB biomarker positive3 High unmet need, No FDA-approved treatments Lacrimal Gland Head & Neck (60-70%), predominantly salivary gland Lung ACC Sites by Organ5 Breast Female Genital Tract Skin May present in other organs Critical need for a precision therapy that targets the molecular driver of ACC ¹ Boyle et al., J Clin Oncol. 2020; Wang et al., Cancer Epidemiol. 2026; Epiphany Partners Inc., EpiOncology Custom Analysis. 2026, ² Remix Market Research, 3 Remix Data on File, 4 Ferraroto et al., 2021, Remix data on file, 5 Li et al., Cancer. 2012;118(16):3945-3953

Current SoC: Up to 75% of ACC patients will require systemic therapy, but only 11-15% ORR with available therapy *Lenvatinib, ¹Tchekmedyian et al., ²J Clin Oncol. 2019, Locati et al., Cancer, 2020, ³ Laurie SA et al., Lancet Oncol 2011 ⁴Putnam Associates, Qualitative Research (Q1 2021) & KOL discussions, SoC – Standard of Care Patients under active surveillance eventually need systemic therapy Surgery standard of care Disease will recur in ~50-75%⁴ of patients Nearly all patients with recurrence will require systemic treatment TKIs and chemo offer low response and tolerability challenges No Yes Active surveillance Surgery or Radiation Amenable to local therapy? No Yes VEGFR TKI* Clinical trial Chemo NCCN (category 2B): 11-15% ORR, 7-9 mo mPFS1,2 13% ORR 5-20 mo mPFS³ Recurrence /Metastasis 50-75% (10-30%) (70-90%) Newly Diagnosed NCCN Guidelines High Unmet Need for Targeted Treatment Patients with symptoms and/or high disease burden will require systemic therapy

REM-422 the first MYB inhibitor in clinical development Majority of ACC patients express oncogenic MYB REM-422 designed to induce degradation of MYB mRNA MYB Expression* MYB translocation drives high expression MYB Expression The MYB poison exon is detectable using an IUO assay in clinical trials *Source: Tempus Lens Real-world database IUO = Investigational Use Only MYB poison exon is normally not included in mature MYB mRNA; REM-422 leads to poison exon inclusion in mature MYB mRNA and subsequent degradation

REM-422 Mechanism: mRNA degradation through Poison Exon inclusion PE excluded from mature mRNA due to unfavorable interaction between the U1snRNP splicing complex and the weak 5’ splice site of the PE U1snRNP U1snRNP REM-422 acts as a specific small molecule molecular glue that enhances the interaction between the U1snRNP complex and the weak 5’ splice site leading to PE inclusion and subsequent degradation via the NMD pathway

ACC PDX model Tumor regressions observed in additional 2 ACC PDX models Biomarker positive treated with REM-422 REM-422 demonstrated antitumor activity in biomarker positive ACC PDX models Biomarker/Poison Exon positive MYB NFIB ACC PDX model Biomarker/Poison Exon negative MYB NFIB Poison exon REM-422 showed selective activity in Biomarker positive preclinical PDX models

A Poison Exon in MYB defines the majority of High-Risk ACC Patients ~25% ACC-I ~ 75% ACC-II ~25-30% ACC-I ~70-75% ACC-II 86% PE +ve 53% PE +ve Molecular profiling data from 307 ACC patients* Poor prognosis regardless of ACC subtype PE +ve PE -ve MYB biomarker (Poison Exon) present in ~60-65% of ACC patients1 MYB biomarker present Type I and Type II ACC1 Associated with significantly worse OS1 Potentially Predicts REM-422 sensitivity 1Source: Tempus AI and Remix Data on File

REM-422 offers potential to become the new standard of care for ACC REM-422 U.S. Sales Estimate: $600M+ Remix is preparing for potential commercial readiness in 2028 CDx Testing Education Patient Support Scaling Potential U.S. Commercial Capabilities for REM-422 ACC Patient Flow¹ Over the course of treatment journey, patients may have multiple recurrences Most patients who recur will eventually require systemic treatment ¹ Illustrative patient flow model

REM-422 Phase 1 studies: Adenoid Cystic Carcinoma AML and High-Risk MDS

18 and 24mg doses evaluated to identify optimal dose Ph1 DOSE ESCALATION (all-comers): N = 69 Abbreviations: PK = Pharmacokinetics; PD = Pharmacodynamics; RP2D = Recommended Phase 2 Dose; R/M = Recurrent/Metastatic; ACC = Adenoid Cystic Carcinoma; DL = Dose Level; N = Number; ORR = Objective Response Rate; Ph = Phase; BICR = Blinded Independent Central Review NCT #: NCT06118086 DL1 (3mg) N = 6 DL2 (6mg) N = 4 DL3 (13mg) N = 4 DL4 (18mg) N = 16 DL5 (24mg) N = 15 DL6 (30mg) N = 9 DL7 (38mg) N = 9 DL8 (48mg) N = 6 Ph2 COHORT (PE+): N = 40-50 PRIMARY OBJECTIVE — SAFETY, RP2D Secondary objectives — PK, PD and efficacy Recurrent or metastatic (R/M) ACC Tumor biopsies retrospectively assessed for MYB status RP2D 24mg Key Eligibility: R/M, locally advanced unresectable ACC Disease progression within 12m Biomarker positive tumor PRIMARY OBJECTIVE — ORR (BICR) Ph1/2 ARIA (A study of REM-422 In Adenoid Cystic Carcinoma) Dosing: oral REM-422 once daily

Datacut: 24Apr2026 Abbreviations: ECOG = Eastern Cooperative Oncology Group (Performance Status) *MYB PE positive + MYB IHC high/PE unknown &ACC Subtype as defined by Ferrarotto et al., 2021 PRIMARY SITE Salivary Major Minor Non-Salivary Trachea/Bronchial/Lung Lacrimal Breast Esophageal 41 (59%) 13 (19%) 8 (12%) 3 (4%) 3 (4%) 1 (1%) HISTOLOGY Solid/high-grade transformation Non-solidUnknown 11 (16%) 35 (51%) 23 (33%) ACC SUBTYPES& I II Unknown 18 (26%) 34 (49%) 17 (25%) BIOMARKER* Positive Negative Unknown 35 (51%)30 (43%) 4 (6%) AGE, MEDIAN (RANGE) 57 (20-82) SEX Female Male 42 (61%) 27 (39%) RACE White Asian Not reported 59 (85%) 6 (9%) 4 (6%) ECOG 0 1 44 (64%) 25 (36%) PRIOR SYSTEMIC RX 0 1 2+ 17 (25%) 16 (23%) 36 (52%) N = 69 N = 69 Demographics and disease characteristics

REM-422 PK/PD REM-422 plasma exposure by dose level Abbreviations: PK = Pharmacokinetics; PD = Pharmacodynamics; RP2D = Recommended Phase 2 Dose 30mg Protein (IHC) Screening On Treatment MYB levels in tumor Observed dose proportional increase in exposures Robust target engagement observed in tumor biopsies 24mg (RP2D) selected based on PK/PD, efficacy and safety results mRNA

Notes: TEAEs were reported using Medical Dictionary for Regulatory Activities, version 28.0; Percentages rounded to nearest whole number; # of subjects (%) reported in table Abbreviations: TEAE = Treatment-Emergent Adverse Event; TRAE = Treatment-Related Adverse Event; SAE = Serious Adverse Event; DLT = Dose-Limiting Toxicity; N = number; RP2D = Recommended Phase 2 Dose 3mg QDN = 6 6mg QDN = 4 12mg QDN = 4 18mg QDN = 16 24mg QDN = 15 30mg QDN = 9 38mg QDN = 9 48mg QDN = 6 TRAE 4 (67) 3 (75) 4 (100) 15 (94) 15 (100) 7 (78) 9 (100) 6 (100) TRAEs ≥ Grade 3 1 (17) 0 1 (25) 3 (19) 1 (7) 2 (22) 6 (67) 4 (67) Discontinuations due to TRAEs 0 0 0 1 (6) 0 2 (22) 2 (22) 1 (17) Interruptions due to TRAEs 0 1 (25) 1 (25) 9 (56) 8 (53) 2 (22) 7 (78) 5 (83) Dose reduction due to TRAEs 0 0 0 2 (13) 1 (7) 1 (11) 4 (44) 2 (33) REM-422 related SAEs 0 0 1 (25) 2 (13) 2 (13) 2 (22) 1 (11) 2 (33) Overall summary of AEs by starting dose level No DLTs observed at any dose level Tolerable Profile particularly at 24mg (RP2D)

3mg QDN = 6 6mg QD N = 4 12mg QDN = 4 18mg QDN = 16 24mg QD N = 15 30mg QDN = 9 38mg QDN = 9 48mg QDN = 6 TOTALN = 69 Lymphocyte count decreased 1 (17) 0 0 1 (6) 0 1 (11) 3 (33) 2 (33) 8 (12) Neutrophil count decreased 0 0 0 0 0 0 1 (11) 1 (17) 2 (3) White blood cell count decreased 0 0 0 0 0 0 1 (11) 1 (17) 2 (3) Aspartate aminotransferase increased 0 0 0 0 0 0 0 1 (17) 1 (1) Blood alkaline phosphatase increased 0 0 0 0 0 0 0 1 (17) 1 (1) Anaemia 0 0 0 1 (6) 0 2 (22) 1 (11) 2 (33) 6 (9) Fatigue 0 0 0 0 0 1 (11) 1 (11) 1 (17) 3 (4) Face oedema 0 0 0 0 0 0 1 (11) 0 1 (1) Malaise 0 0 0 0 0 0 1 (11) 0 1 (1) Peripheral motor neuropathy 0 0 0 1 (6) 1 (7) 1 (11) 0 0 3 (4) Peripheral sensory neuropathy 0 0 0 0 0 1 (11) 1 (11) 0 2 (3) Muscular weakness 0 0 0 1 (6) 0 1 (11) 0 0 2 (3) Acute kidney injury 0 0 0 0 0 0 1 (11) 0 1 (1) Proteinuria 0 0 0 0 0 0 1 (11) 0 1 (1) Epistaxis 0 0 1 (25) 0 0 0 0 1 (17) 2 (3) Notes: TRAEs were reported using Medical Dictionary for Regulatory Activities, version 28.0; Percentages rounded to nearest number; # of subjects (%) reported in table Abbreviations: TRAE = Treatment-Related Adverse Event, SOC = Systems Organ Class, QD = once a day; RP2D = Recommended Phase 2 Dose. TRAEs Gr3-4 by preferred term Only 2 patients had Gr4 TRAEs: 1) 38mg: neutrophil and lymphocyte counts decreased 2) 48mg: lymphocyte count decreased Minimal TRAEs Gr3-4 at 24mg (RP2D) underscores potential safety and tolerability

Radiographic images Baseline On-treatment (M5) Note: Efficacy dataset includes all patients with measurable target lesions at baseline and at least 1 post-treatment scan (N = 60) Change in tumor size from baseline by biomarker status Biomarker positive tumors demonstrated robust anti-tumor activity with many remaining on-treatment

Response evaluable subgroup N # of Responders ORR (%) DCR (%) BM+ ≥ 24mg 19 7 37% 95% BM+ at 24mg 7 3 43% 100% Notes: 1) ORR includes uPR; 2) Patients with starting doses ≥30mg who remain on treatment reduced to 24mg; 3) One patient (30mg) excluded due to treatment discontinuation unrelated to REM-422 during C1. Abbreviations: mDOT= median Duration of Treatment; mDOR = median Duration of Response; BM = Biomarker; DCR = Disease Control Rate; ORR = Objective Response Rate, N = Number; RP2D = Recommended Phase 2 Dose; uPR = unconfirmed PR Best percentage change in tumor size from baseline by dose Clinical responses achieved in biomarker positive tumors at doses of ≥12mg In biomarker positive tumors, ORR = 43% and DCR = 100% indicates encouraging clinical activity at RP2D Best clinical activity noted at 24mg (RP2D) due to both robust target engagement and tolerability

Notes: *Treatment beyond progression; + = ongoing; †Pt on tx-hold; ACC Subtype as defined by Ferrarotto et al., 2021 Abbreviations: cPR= confirmed PR; uPR = unconfirmed PR; Pt = Patient, TL = Target Lesions; Tx = treatment; DOT = Duration of Treatment; DOR = Duration of Response Pt ID Dose Level Response Histology ACC Subtype # Prior Lines of Therapy DOT (months) DOR (months) 1 12mg cPR Solid component ACC-II 0 23+ 15+ 2 18mg cPR Cribriform ACC-I 2+ 10+ 6+ 3 24mg uPR Cribriform ACC-II 1 20+ * 6 4 24mg cPR Unknown ACC-I 1 19+ 12+ 5 24mg cPR Solid component Unknown 2+ 19+ 13+ 6 38mg cPR Unknown Unknown 2+ 12+ 5+ 7 38mg uPR Tubular ACC-II 2+ 16+ 1+ 8 48mg uPR Cribriform ACC-I 2+ 5 2 9† 48mg cPR Unknown Unknown 2 14+ 7+ Sustained objective responses demonstrated across ACC-I/II and irrespective of prior lines of therapy Anti-tumor activity observed across ACC subtype, histologies, and after multiple lines of therapy (including ADCs) Long durability with patients on therapy for up to 2 years and ongoing (mDOR not reached) Responses have deepened over time

REM-422 ACC Program Summary Adenoid Cystic Carcinoma is a high unmet medical need tumor with no FDA approved therapies Prior therapies demonstrate an ORR range 0-15%, mPFS ~7 months highlighting need for more effective therapies ORR of 43% & DCR of 100% at RP2D with durable responses observed at last data cut-off FDA authorized Remix to proceed with an ongoing Phase 2 study with proposed key elements, including: recommended dose, biomarker positive population, and single arm study design for potential registration Potentially registrational Ph2 study ongoing, >60% on study with full enrollment anticipated in H2'26 As Phase 2 data matures, we expect to continue dialog with the FDA to discuss most efficient registrational path; ORR and DOR data expected in mid-2027

AML and High-Risk MDS are MYB-driven malignancies Acute myelogenous leukemia (AML) & high-risk myelodysplastic syndrome (HR-MDS) ~25,000 treatable AML/HR-MDS patients in the US MYB is a master transcriptional regulator of leukemogenesis REM-422 is active across multiple genetic subtypes in AML preclinical models (e.g. NPM1, FLT3, rMLL, IDH, p53, Ras etc) Cancer Dependency Map data AML cell lines have a lineage-wide dependency on MYB

REM-422: Robust monotherapy/combination activity in AML models M4 (myelomonocytic) AML pt relapsed after chemotherapy with complex cytogenetics Vehicle REM-422 10 mg/kg SURVIVAL BENEFIT IN PDX MODEL Monotherapy Activity ERADICATED hCD45+ AML BLASTS Combination Activity ADDITIVE/SYNERGISTIC ACTIVITY IN LEUKEMIA CELL PANEL REM-422 has shown preclinical activity as a monotherapy and is additive/synergistic activity with multiple therapies NOTE: Preclinical results may not be predictive of clinical outcomes

Ph1 Study in Patients with R/R AML or HR-MDS DOSE ESCALATION Up to 2 dose levels evaluated to identify optimal dose PRIMARY OBJECTIVE — SAFETY, MTD, RP2D Secondary and exploratory objectives — PK, PD and efficacy DL1 (1mg) No. treated = 3 DL2 (3mg) No. treated = 4 DL3 (6mg) No. treated = 5 DL4 (12mg) No. treated = 4 DL5 (18mg) No. treated = 4 EXPANSION PHASE (N=20) PRIMARY OBJECTIVE — ORR Secondary objectives PFS, DOR, OS, CBR, Safety RP2D MTD – Maximum tolerated dose, RP2D – recommended Phase 2 dose, PK – pharmacokinetics, PD – pharmacodynamics, ORR – Overall Response Rate, PFS – Progression Free Survival, DOR – Duration of Response, OS – Overall Survival, CBR – Clinical Benefit Rate Azole cohorts DL1 (3mg) No. treated = 4 DL2 (6mg) No. treated = 8 DL3 (12mg) No. treated = 5 DL4 (18mg) No. Treated = 4 Non-Azole cohorts Consistent PK across both cohorts to date with no evidence of azole interaction DL5 (24mg) No. Treat = 5 DL6 (24mg) Treated = 5 30 mg dose level completed

Preliminary Anti-tumor Activity. RP2D not reached Dose dependent reduction of MYB mRNA levels was observed in bone marrow biopsies Additional patients with blast count reductions observed in ongoing dose escalation study From live database last updated Mar 18, 2026 Indication Dose (mg) Prior Therapies Cytogenetics /Mutations Response HR-MDS 6 Decitabine/cedazuridine, fludarabine, MUD, decitabine/cedazuridine P53, MSH3, complex karyotype, monosomy 17 CR (durable 15 months ongoing) AML 12 Venetoclax/Azacitidine STAG2, TET2, SRSF2, CUX1, MPL CRi (durable for 6 months) AML 12 Multiple including HSCT, Ven, MTX PTPN11, PHF6 MLFS HR-MDS 30 CD70 Ab/Aza, MUD, decitabine/cedazuridine P53, DNMT3A, MRE11 CRuni HR-MDS 30 Magrolimab/Aza, Aza, lenalidomide P53, ASXL1 CRL CR = Complete Remission, Cri Complete Remission with Incomplete Recovery, CRuni = Complete Remission Unilineage, CRL = Complete Remission with Limited Count Recovery, MLFS = Morphological Leukemia-Free State

REM-422 indication expansion potential in heme and solid tumors Breast Cancer MYB dysregulation MYB high expression Lymphoma Overexpression Colon Cancer Overexpression Disease Tumor agnostic Fusion & amplification MYB DEPENDENCY ACROSS SEVERAL LINEAGES (DepMap) MYB DYSREGULATION IN BREAST CANCER PMIDs: 17690249 and 38593782

Pipeline programs

Genetically Defined Diseases Patient Selection Criteria REMIX TARGETS& DRUGS DATA SCIENCE Integrated database of >350k internal and external transcriptome datasets Proprietary algorithms & AI/ML BIOLOGY & BIOMOLECULAR SCIENCES Functional & genetic validation of targets Fit for purpose high- throughput multiplexed screens MEDICINAL & COMPUTATIONAL CHEMISTRY Proprietary small molecule library targeting RNA/protein complexes RNA-protein complex structural biology

Targeting MYC, an oncogenic transcription factor dysregulated across cancer MYC amplification/activation occurs in ~28% of all tumors Remix developing a novel mRNA degrader approach targeting a regulator of MYC to prevent signaling via all 3 MYC paralogs Indication Total US New Cases (k/yr) MYC dysregulation Diffuse large B-cell lymphoma (DLBCL) 16-20 c-MYC translocation Burkitt lymphoma (BL) 3 Ovarian 21 MYC amplification frequencies >20% (c-MYC, N-MYC, or L-MYC) Esophageal 22 Gastric 30 Head and neck 58 Pancreatic 67 Colorectal 154 >1/3 of patients have c-MYC overexpression Prostate 313 Wang, et al., 2024 Blood Cancer J Blum et al., 2004 Blood Clipson et al., 2015 J Pathol Clin Res Schaub et al., 2018 Cell Systems US case numbers per SEER Llombart et al., eBioMedicine, 2021

Discovery program targeting oncogenic MYC signaling high prevalence dysregulation across multiple solid and heme malignancies MYC-dependent upregulated pathways MYC-dependent downregulated pathways Small molecule mRNA degrader phenocopies genetic knockdown Regulator siRNA MYC siRNA Small molecule Poison Exon inclusion mRNA reduction qPCR, 24h, n = 3 Western Blot, 72h RXSM-1244 Protein anti-β-actin DMSO Protein depletion Novel mRNA degraders potently reduce mRNA and protein levels through a poison exon inclusion mechanism IC50 = 18 nM DC50 = 30 nM

RXSM-1244 demonstrated potent mRNA and protein target engagement and robust tumor growth inhibition in a mouse CDX model protein reduction mRNA reduction QDx3 study. mRNA and protein analysis from samples collected 6 hr post-last dose poison exon inclusion anti-Target Protein anti-Vinculin RXSM-1244 Vehicle RXSM-1244 showed well behaved rodent PK profile Observed in vivo poison exon inclusion, concomitant mRNA degradation and protein reductions Induced regressions in multiple MYC addicted cell-line derived xenograft models MYC-amplified CDX BWL = -8.9%

Remix Therapeutics is Well-Positioned For Significant Growth Near-Term Inflection Points Experienced Management Team and Investors Strong Pro-Forma Balance Sheet REM-422 in ACC - ORR and DoR data expected in mid’27, potential for NDA filing as early as H2'27 REM-422 in AML/MDS: RP2D and initial data expected in mid’27 Discovery program Development Candidate Progression Strong Management Team with significant expertise growing and commercializing assets Robust investor syndicate led by Atlas, Column Group, Foresite, Arch, Casdin, Surveyor and Alexandria ~$245MM of capital investment to date from top-tier investors Potential for over $1 billion in milestone payments and tiered royalties from collaboration with Roche $100M PIPE in 2026 and net cash from Passage Bio Expected pro-forma cash runway into H1'28

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Date	Price Target	Rating	Analyst
6/10/2026		Buy → Neutral	Guggenheim
4/21/2026		Buy → Hold	TD Cowen
4/21/2026	$7.00	Buy → Neutral	Chardan Capital Markets
4/21/2026	$8.00	Outperform → Neutral	Wedbush
3/31/2026	$30.00	Outperform	Oppenheimer
2/10/2026	$21.00	Buy	Chardan Capital Markets
11/29/2024	$3.00 → $4.00	Outperform	Wedbush
9/3/2024	$7.00	Buy	Rodman & Renshaw

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SEC Form 425 filed by Passage Bio Inc.

7/21/26 9:40:53 PM ET

$PASG

Biotechnology: Biological Products (No Diagnostic Substances)

Health Care

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425 1 ny20077915x2_425.htm 425

Filed by Passage Bio, Inc.

pursuant to Rule 425 under the Securities Act of 1933

and deemed filed pursuant to Rule 14a-12

under the Securities Exchange Act of 1934

Subject Company: Passage Bio, Inc.

Filer’s SEC File No.: 001-39231

Date: July 21, 2026

Cautionary Statement Regarding Forward-Looking Statements

Additional Information and Where to Find It

No Offer or Solicitation

Participants in the Solicitation

REM-422 Phase 1 studies: Adenoid Cystic Carcinoma AML and High-Risk MDS

Pipeline programs

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Recent Analyst Ratings for

$PASG

Date	Price Target	Rating	Analyst
6/10/2026		Buy → Neutral	Guggenheim
4/21/2026		Buy → Hold	TD Cowen
4/21/2026	$7.00	Buy → Neutral	Chardan Capital Markets
4/21/2026	$8.00	Outperform → Neutral	Wedbush
3/31/2026	$30.00	Outperform	Oppenheimer
2/10/2026	$21.00	Buy	Chardan Capital Markets
11/29/2024	$3.00 → $4.00	Outperform	Wedbush
9/3/2024	$7.00	Buy	Rodman & Renshaw

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SEC Form 425 filed by Passage Bio Inc.

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SEC Form 425 filed by Passage Bio Inc.

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