Quarterly Report for Quarter Ending September 30, 2026 (Form 10-Q)

Management's Discussion and Analysis of Financial Condition and Results of Operations.

You should read the following discussion and analysis of our financial condition and results of operations in conjunction with our consolidated financial statements and the related notes and other financial information included elsewhere in this Quarterly Report on Form 10-Q. In addition to historical financial information, this discussion and analysis contains forward-looking statements based upon current expectations that involve risks and uncertainties, such as statements of our plans, objectives, expectations, intentions and beliefs. Our actual results could differ materially from those anticipated in these forward-looking statements as a result of various factors, including those set forth in the section titled "Risk Factors" under Part II, Item 1A below.

Overview

We are a clinical stage genetic medicines company that has historically focused on improving the lives of patients with neurodegenerative diseases through the development and advancement of cutting-edge, one-time gene therapies designed to target critical underlying pathologies in these conditions. We have terminated or wound down our principal programs, collaboration, license and manufacturing arrangements and, as described in the section titled "Merger Agreement," on June 24, 2026, we entered into an Agreement and Plan of Merger, which was subsequently amended and restated on September 2, 2026, or, as further amended, the Merger Agreement, with Remix Therapeutics, Inc., or Remix, a Delaware corporation. In connection with the wind-down, we terminated our development services and clinical supply arrangements with Catalent Maryland, Inc., or Catalent, our collaboration agreement with Gemma Biotherapeutics, Inc., or Gemma, and terminated our license with the Trustees of the University of Pennsylvania, or Penn, with respect to PBFT02, our former lead product candidate.

Merger Agreement

On June 24, 2026, we entered into the Merger Agreement with Remix, Peregrine Merger Sub, Inc., or the Merger Sub, a Delaware corporation and wholly-owned subsidiary of us, and Peregrine Merger Sub II, LLC, or the Merger Sub II, a Delaware limited liability company and wholly-owned subsidiary of us. Upon the terms and subject to the satisfaction or waiver of the conditions described in the Merger Agreement, Merger Sub will be merged with and into Remix, with Remix surviving as a wholly-owned subsidiary of us and immediately following thereof, Remix will be merged into Merger Sub II, with Merger Sub II surviving as a wholly-owned subsidiary of us (such transaction, the Merger). The Merger is intended to qualify as a tax-free reorganization for U.S. federal income tax purposes and is expected to close in the fourth quarter of 2026.

On September 2, 2026, concurrently with the execution and delivery of the amended and restated Merger Agreement, Remix entered into an amended and restated subscription agreement, or, as amended, the Subscription Agreement, with certain accredited investors named therein, or the Investors, pursuant to which the Investors agreed to purchase shares of Remix common stock and Remix pre-funded warrants for aggregate gross proceeds of approximately $70.0 million. The Subscription Agreement, together with the issuance by Remix of approximately $30.0 million of convertible promissory notes in June 2026, comprises the concurrent financing, or the Concurrent Financing, which is expected to result in aggregate gross proceeds of approximately $100.0 million. The closing of the Concurrent Financing is conditioned upon the satisfaction or waiver of the conditions to the Merger, as well as certain other conditions. The shares of Remix common stock issued in the Concurrent Financing will convert into shares of Passage Bio Common Stock in the Merger and, immediately following the Merger, are expected to represent approximately 29% of the outstanding shares of the combined company. The Remix pre-funded warrants to be issued in the Concurrent Financing will convert into the right to receive shares of Passage Bio Common Stock in the Merger. The Subscription Agreement amended and restated the original subscription agreement entered into by Remix and the Investors on June 24, 2026, or the Original Subscription Agreement.

Subject to the terms and conditions of the Merger Agreement, at the effective time of the Merger, or the Effective Time, (a) each outstanding share of Remix common stock or preferred stock (other than shares issued in the Concurrent Financing and shares held in treasury or owned by us, Merger Sub, or Remix) will be converted into the right to receive a number of shares of Passage Bio Common Stock equal to the Exchange Ratio set forth in the Merger Agreement, or the Exchange Ratio, and (b) each such share issued in the Concurrent Financing will be converted at the Concurrent

Financing Exchange Ratio set forth in the Merger Agreement. Each outstanding option to purchase Remix capital stock will be converted into an option to purchase Passage Bio Common Stock based on the Exchange Ratio and subject to adjustment as set forth in the Merger Agreement.

Under the Exchange Ratio and Concurrent Financing Exchange Ratio formulas in the Merger Agreement, immediately after the Closing, on a pro forma basis and based upon the number of shares of Passage Bio's Common Stock expected to be issued in connection with the Merger, pre-Merger equityholders of Remix (other than investors in the Concurrent Financing) are expected to own approximately 65% of the combined company, pre-Merger equityholders of the Company are expected to own approximately 6% of the combined company and the investors in the Concurrent Financing are expected to own approximately 29% of the combined company (assuming proceeds from the Concurrent Financing of $100.0 million), in each case, calculated on a fully diluted basis, using the treasury stock method, and subject to certain assumptions, including (i) a valuation for the Company of approximately $20.0 million (assuming we have net cash of $5.0 million as of the closing of the Merger), (ii) an equity value for Remix of $226.0 million, and (iii) the relative capitalization of the Company and Remix. The percentage of the combined company that each party's equityholders will own following the Closing is subject to certain adjustments, including the amount of our net cash at the Closing. As of the date of this Quarterly Report, we currently anticipate our net cash at the Closing to be approximately $10.9 million.

Prior to the Effective Time, we expect to declare a distribution of one contingent value right, or CVR, for each outstanding share of Passage Bio Common Stock to holders of record as of the close of business on the last business day prior to the closing of the Merger, and to enter into a Contingent Value Rights Agreement, or the CVR Agreement, with Computershare Trust Company, N.A., as rights agent. Each CVR entitles the holder to receive its pro rata share of 100% of the Legacy Asset Payments (as defined in the CVR Agreement) actually received by us or our subsidiaries during the applicable CVR period, less Permitted Deductions (as defined in the CVR Agreement). Legacy Asset Payments consist of certain payments received from Gemma under our MLD and GM1 exclusive license agreements, and the applicable CVR periods end on December 31, 2027 with respect to MLD Payments and July 31, 2028 with respect to GM1 Payments.

On July 21, 2026, we filed with the SEC the Registration Statement, which includes a proxy statement/prospectus relating to the Merger and the related transactions, including the issuance of shares of Passage Bio Common Stock in the Merger and the matters to be submitted to our stockholders for their approval. The Registration Statement was declared effective by the SEC on October 9, 2026, and on October 9, 2026, we filed the definitive proxy statement/prospectus with the SEC and commenced mailing it to our stockholders. A special meeting of our stockholders was held on November 5, 2026 and our stockholders approved all the proposals described in the proxy statement/prospectus, including the issuance of shares of Passage Bio Common Stock in the Merger, an amendment to our certificate of incorporation to effect a reverse stock split of our common stock at a ratio within the range of 1-for-2 to 1-for-10, and an amended and restated certificate of incorporation that, among other things, would change our name to "Remix Therapeutics, Inc." The Merger remains subject to the satisfaction or waiver of the other conditions to the closing of the Merger. Following the closing of the Merger, the combined company's common stock is expected to trade on Nasdaq under the ticker symbol "RMTX," subject to approval of the combined company's initial listing application.

Our Pipeline

We are a clinical-stage genetic medicines company that has historically focused on developing one-time, adeno-associated virus, or AAV, based gene therapies designed to treat neurodegenerative diseases. Our lead product candidate was PBFT02, and we have also pursued additional preclinical and outlicensed programs. During the second quarter of 2026, we terminated or began winding-down our principal program, collaboration, license, and manufacturing arrangements.

PBFT02 for the Treatment of FTD-GRN

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Our lead clinical product candidate was PBFT02, a gene replacement therapy that utilizes an adeno-associated virus serotype 1, or AAV1, capsid to deliver a functional granulin gene, or GRN, encoding progranulin, or PGRN, to the brain

via intra cisterna magna, or ICM, administration. PBFT02's lead indication was frontotemporal dementia, or FTD, caused by progranulin deficiency, or FTD-GRN, an inheritable form of FTD resulting from reduced PGRN production.

Currently, there are no disease-modifying therapies approved for the treatment of FTD-GRN, and we estimate the prevalence of FTD-GRN in the United States and Europe is approximately 18,000, based on available literature. Supported by findings in preclinical studies, we believed that PBFT02 may provide FTD-GRN patients with significantly improved outcomes. We selected the AAV1 capsid and ICM administration for PBFT02 because this approach led to extensive and robust vector delivery throughout the brain and spinal cord of non-human primates, or NHPs, and due to the higher PGRN levels in cerebrospinal fluid, or CSF, achieved using AAV1 as compared with other serotypes tested. ICM administration of AAV1 to NHPs resulted in elevated CSF levels of human PGRN when compared with CSF levels in healthy human subjects, and in excess of levels achieved in NHPs with AAVhu68 or AAV5. We had an active Investigational New Drug, or IND, application from the U.S. Food and Drug Administration, or the FDA, and approved clinical trial authorizations, or CTAs, in multiple countries for PBFT02. We previously conducted the upliFT-D trial, an international, multi-center, open-label, single-arm Phase 1/2 clinical trial of PBFT02 in patients with a diagnosis of symptomatic FTD-GRN.

PBFT02 for the Treatment of FTD-C9orf72 and ALS

We also evaluated PBFT02 for the treatment of additional adult neurodegenerative diseases where we believe elevated PGRN levels could provide benefits. This approach stemmed from PGRN's pleiotropic cellular effects including the regulation of microglial activation and lysosomal function, and in particular its potential to ameliorate TDP-43 pathology. TDP-43 is a ribonucleic acid / deoxyribonucleic acid, or RNA/DNA, binding protein that normally resides in the nucleus where it regulates gene expression, RNA splicing, RNA trafficking, and mRNA turnover. Cytoplasmic TDP-43 pathology is a hallmark of multiple neurodegenerative conditions including FTD-GRN, FTD-C9orf72, approximately 95% of sporadic amyotrophic lateral sclerosis, or ALS, and approximately 50% of sporadic FTD. In these disorders, hyperphosphorylated TDP-43 accumulates in the cytoplasm of cell bodies and dendritic processes of neurons and glia. Experimental evidence suggests that loss of TDP-43's normal nuclear function contributes to neurodegenerative processes.

The potential for benefit of increased PGRN in disorders with TDP-43 pathology has been demonstrated by third-party preclinical studies in mice and zebrafish which showed that increased PGRN levels reduced TDP-43 pathology and associated toxicities. We anticipated that elevating neuronal PGRN levels in diseases with TDP-43 pathology may provide significant benefits to patients. We previously initiated preclinical studies to extend these initial observations. Based on available literature, we estimate the prevalence of FTD-C9orf72 in the United States and Europe is approximately 21,000.

There are no disease modifying therapies approved for the treatment of FTD-C9orf72.

In April 2026, we determined to wind-down our clinical development programs related to PBFT02.

PBFT02 for the Treatment of AD

We also evaluated reduced PGRN levels having the potential to improve the course of Alzheimer's disease, or AD, in patients who carry the GRN rs5848 single nucleotide polymorphism, or GRN SNP. The GRN SNP has an allele frequency of approximately 30% and is associated with reduced PGRN levels. Its presence has been shown to confer an increased risk for AD onset. Within symptomatic AD patients, GRN SNP carriers not only have lower levels of PGRN, but also higher levels of CSF tau, which correlates with increased AD pathology in the brain and more rapid disease progression. Third party preclinical studies in animal models have demonstrated that low levels of PGRN may exacerbate AD pathology and, conversely, high levels of PGRN may reduce AD pathology. In April 2026, we decided to wind-down our clinical development programs related to PBFT02.

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Clinical Supply

Through our partners, we manufactured the PBFT02 clinical supply to support completion of the Phase 1/2 clinical trial in FTD-GRN and FTD-C9orf72.

On June 23, 2026, we delivered written notice to Catalent to terminate the amended and restated development services and clinical supply agreement in its entirety, effective as of June 23, 2026. We determined to terminate this agreement in connection with the wind-down of our gene therapy programs and the proposed Merger, and we are not obligated to pay Catalent any termination fee in connection with the termination.

Research Programs

We had a preclinical research program through the Gemma Collaboration Agreement to develop a genetic medicine to treat Huntington's disease, or HD.

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HD is an autosomal dominant disorder caused by a mutation in the huntingtin gene, or HTT, in which a CAG trinucleotide repeat tract in the DNA is expanded. This leads to the expression of mutant huntingtin protein. HTT CAG repeat tracts are unstable and can continue to elongate over time, termed somatic instability. In neurons, CAG expansion occurs at different rates in different cells, and CAG expansion to above a certain threshold leads to neuronal dysfunction and death. DNA repair proteins such as MSH3 play a key role in driving somatic instability in HD, by erroneously incorporating extra CAG repeats into HTT DNA in certain circumstances. Published literature has shown that reducing somatic instability by decreasing MSH3 expression reduced disease pathology in HD mice. Further, published human genetic studies have shown that certain genetic MSH3 variants which reduce somatic instability are associated with delayed disease onset and slowed progression in HD patients.

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Our approach was to reduce somatic instability and thereby slow neurodegeneration in HD by suppressing MSH3 expression in the brain, via AAV-mediated delivery of a miRNA gene.

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Beyond this program, through the Gemma Collaboration Agreement, we had the option to license programs for four additional new indications in CNS diseases.

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On May 21, 2026, we provided written notice to Gemma to terminate the Gemma Collaboration Agreement, which termination became effective on August 21, 2026. Upon termination, we no longer have any rights to the research programs or the options for new CNS indications previously available to us under the Gemma Collaboration Agreement.

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Business Overview

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We were incorporated in July 2017 under the laws of the State of Delaware. Since inception, our operations have consisted primarily of conducting preclinical studies, developing licensed technology, conducting clinical trials, and developing and manufacturing clinical supply to support clinical trials. We have incurred recurring losses, the majority of which are attributable to research and development activities, and negative cash flows from operations. Historically, we have funded our operations through the sale of convertible preferred stock and public offerings of common stock. Our net losses were $4.7 million and $7.7 million for the three months ended September 30, 2026 and 2025, respectively, and $20.1 million and $32.5 million for the nine months ended September 30, 2026 and 2025, respectively. As of September 30, 2026, we had an accumulated deficit of $724.9 million. We expect to continue to incur net losses and negative cash flows from operations for the foreseeable future.

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As of September 30, 2026, we had cash and cash equivalents of $20.2 million, which may not be sufficient to fund our operating expenses and capital expenditure requirements for at least twelve months following the date these consolidated financial statements are issued.

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We would need additional funds to meet operational needs and capital requirements for clinical trials, other research and development expenditures, and business development activities. We currently have no credit facility or committed

sources of capital. Because of the numerous risks and uncertainties associated with the development and commercialization of our product candidates, we are unable to estimate the amounts of increased capital outlays and operating expenditures associated with any future clinical studies.

On April 20, 2026, we announced that we have initiated a review of strategic alternatives to maximize shareholder value and on April 28, 2026, in connection with our review of strategic alternatives, we announced a restructuring of our workforce, or the Restructuring Plan, to decrease operating expenses by reducing the workforce by approximately 75%. The implementation of the Restructuring Plan was substantially completed in the second quarter of 2026 and was completed in the third quarter of 2026. We originally estimated the aggregate severance and related costs for the Restructuring Plan would be approximately $3.3 million, which was recorded primarily in the second quarter of 2026. These estimates were subject to a number of assumptions. As of September 30, 2026, we have paid $3.4 million for severance and related costs associated with the Restructuring Plan. There are no unpaid severance or related costs associated with the Restructuring Plan as of September 30, 2026.

As described above under "Merger Agreement," on June 24, 2026, we entered into a Merger Agreement with Remix, which is expected to be completed in the fourth quarter of 2026.

If we do not complete the proposed transaction with Remix and until such time, if ever, as we can generate substantial product revenue, we expect to finance our operations through a combination of equity offerings, debt financings, collaborations, strategic alliances, reverse merger or other business combination transactions, and marketing, distribution or licensing arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, existing stockholders' ownership interest will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect existing stockholders' rights as common stockholders. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making acquisitions or capital expenditures or declaring dividends. If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or drug candidates, or grant licenses on terms that may not be favorable to us. If we pursue another reverse merger or other business combination transaction, we may be subject to significant transaction costs, our stockholders may experience substantial dilution, our management team may change, and we may not achieve the anticipated benefits of such a transaction.

As a result of these factors, there is substantial doubt about our ability to continue as a going concern within one year after the date the interim consolidated financial statements included in this Quarterly Report on Form 10-Q are issued.

Financial Operations Overview

License Agreements

University of Pennsylvania

As a result of the Outlicense Transaction Agreements, as discussed below, we restructured our research, collaboration and licensing agreement with Penn, as amended, previously the Penn Agreement and now referred to as the Penn License Agreement. Pursuant to the Penn License Agreement, as of July 31, 2024, we (i) terminated the funding of discovery research programs; (ii) terminated the research and exploratory research programs; (iii) terminated the remaining eight options we had for future CNS indications; (iv) terminated the transaction fee payable to Penn in the event of certain corporate transactions; and (v) retained our current exclusive and non-exclusive licenses to our programs in FTD, GM1, Krabbe, MLD and certain platform technologies resulting from the discovery programs that we funded.

For our licensed programs in GM1, Krabbe and MLD, the Penn License Agreement requires that we make payments of up to $16.5 million per product candidate. Each payment will be due upon the achievement of specific development milestone events by such licensed product for a first indication, reduced development milestone payments for the second and third indications and no development milestone payments for subsequent indications. In addition, on a product-by-product basis, we are obligated to make up to $55.0 million in sales milestone payments on each licensed product based

on annual worldwide net sales of the licensed product in excess of defined thresholds. Pursuant to the Amended Gemma Sublicenses, as discussed below, Gemma is responsible for the payments to Penn related to GM1, Krabbe and MLD, collectively the Outlicensed Programs.

Upon successful commercialization of a product using the licensed technology, we are obligated to pay to Penn, on a licensed product-by-licensed product and country-by-country basis, tiered royalties (subject to customary reductions) in the mid-single digits percentage on annual worldwide net sales of such licensed product. In addition, other than the Amended Gemma Sublicenses, we are obligated to pay to Penn a percentage of sublicensing income, ranging from the mid-single digits to low double digits, for sublicenses under the Penn License Agreement. The agreement will expire on a licensed product-by-licensed product and country-by-country basis upon the later of (i) the expiration of the last valid claim of the licensed patent rights that covers the exploitation of such licensed product in such country, and (ii) the expiration of the royalty period. Pursuant to the Amended Gemma Sublicenses, Gemma is responsible for the payments to Penn related to the Outlicensed Programs.

On June 23, 2026, we delivered written notice to Penn to terminate the Penn License Agreement, solely with respect to its product candidate referred to as PBFT02 for all indications licensed to us thereunder for such product candidate, including frontotemporal dementia with granulin mutations. This partial termination became effective on September 23, 2026, and we no longer have any rights under the Penn License Agreement to develop or commercialize PBFT02. The Penn License Agreement will remain in effect with respect to all non-terminated licensed products.

Gemma - Research, Collaboration and License Agreement

In connection with the transfer of the Outlicensed Programs, on July 31, 2024, we entered into the Gemma Collaboration Agreement. Pursuant to the Gemma Collaboration Agreement, (i) Gemma will conduct certain preclinical and IND application enabling work for our active research program in Huntington's disease and a currently paused research program in TLE, which were previously being conducted by Penn under the Penn Agreement and (ii) Gemma will grant us options to conduct mutually agreed research programs in four new CNS indications.

On May 21, 2026, we provided written notice to Gemma to terminate the Gemma Collaboration Agreement, which terminated on August 21, 2026. Upon termination, we no longer have any rights to the research programs or the options for new CNS indications previously available to us under the Gemma Collaboration Agreement.

Gemma - Sublicense Agreements and Transition Services Agreement

In connection with the transfer of the Outlicensed Programs to Gemma, in July 2024, we entered into the Gemma Sublicenses. On May 7, 2025, we agreed to amend each of the Gemma Sublicenses to revise certain financial terms related to the Outlicensed Programs, or the Amended Gemma Sublicenses. Pursuant to the Amended Gemma Sublicenses, we are entitled to receive (i) an aggregate total of $15.0 million in initial payments for licenses and clinical product supply, of which $10.0 million has been received and $5.0 million of which was due in March 2026, and has not yet been received; (ii) an additional $5.0 million contingent on Gemma completing certain business milestones; (iii) up to an additional $114.0 million in development and commercial milestone payments; and (iv) single digit royalties as a percentage of annual worldwide net sales in exchange for sublicenses to relevant intellectual property, transfer of regulatory dossiers and transfer of clinical trial materials and product supply related to the Outlicensed Programs. In addition, Gemma is responsible for all payments to Penn related to the Outlicensed Programs under the Penn License Agreement.

In addition, we entered into the Transition Services Agreement, as amended by the First Amendment to the Transition Services Agreement, dated January 31, 2025, pursuant to which, we provided transitional services at cost to Gemma through May 31, 2025, and are entitled to reimbursement for transitional services performed retroactively from March 1, 2024, related to the transfer of the Outlicensed Programs. As of September 30, 2026, we have collected $10.0 million in initial payments and $4.8 million in transition services payments under these agreements. In addition, we have applied $2.2 million in amounts owed to Gemma for the Huntington's disease program against amounts due to us for transition services.

As of September 2026, the services under the Transition Services Agreement have been completed and the Amended Gemma Sublicenses remain in effect.

We refer to the Amended Gemma Sublicenses, the Transition Services Agreement, and the Gemma Collaboration Agreement, collectively, as the Outlicense Transaction Agreements.

Collaboration and Manufacturing and Supply Agreements

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Catalent

We had previously entered into a collaboration agreement, and a development services and clinical supply agreement, or the Amended Catalent Agreements, with Catalent Maryland, a unit of Catalent, Inc. acquired by Novo Holdings A/S, or Catalent, to secure clinical scale manufacturing capacity for batches of active pharmaceutical ingredients for our gene therapy product candidates. Under the terms of the Amended Catalent Agreements, Catalent agreed to manufacture batches of drug product for our gene therapy product candidates.

The Amended Catalent Agreements were expected to remain in effect until November 6, 2030, and established a limited exclusive relationship between us and Catalent for the manufacture of bulk drug substance and drug product for our adeno-associated virus delivery therapeutic product candidates for the treatment of FTD and GM1. Under the Amended Catalent Agreements, the limited exclusive relationship would convert to a non-exclusive relationship (i) in the event Catalent failed to meet certain performance standards and (ii) following certain conditional events related to the divestiture by us of either FTD or GM1, in which case we would pay Catalent certain fees. In the event of certain transactions, we may terminate the Amended Catalent Agreements for convenience with respect to such products, in which case, we would pay Catalent a certain termination fee.

The outlicensed and completed transition of GM1 to Gemma under the Outlicense Transaction Agreements is deemed by Catalent to be a divestiture under the Amended Catalent Agreements. As such, we were required to make payment of $0.9 million to Catalent which was paid as of September 30, 2026.

On June 23, 2026, we delivered written notice to Catalent to terminate the amended and restated development services and clinical supply agreement in its entirety, effective as of June 23, 2026. We determined to terminate this agreement in connection with the wind-down of our gene therapy programs and the proposed Merger, and we are not obligated to pay Catalent any termination fee in connection with the termination.

Components of Results of Operations

Research and Development

Research and development expenses consist primarily of costs incurred in connection with the development of our product candidates. These expenses include:

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We track outsourced development expenses and other external research and development expenses to specific product candidates on a program-by-program basis, such as fees paid to CROs, CDMOs and research laboratories in connection

with our preclinical development, process development, manufacturing and clinical development activities, expenses incurred under our prior collaboration with Penn, and expenses incurred under the Gemma Collaboration Agreement. However, we do not track our internal research and development expenses on a program-by-program basis as they primarily relate to compensation, lab operations and lab facility costs, and other expenses which are deployed across multiple projects under development.

Research and development activities are central to our business model. Product candidates in later stages of clinical development generally have higher development expenses than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials.

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We expect our research and development expenses to decrease in the future due to the winding down of our development programs, reductions in staff and reductions in consulting services as a result of limited remaining operations.

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General and Administrative Expenses

General and administrative expenses consist primarily of personnel expenses, including salaries, benefits and share-based compensation expense, for employees and consultants in executive, finance, accounting, legal, information technology, product strategy, quality, regulatory, operations and human resource functions. General and administrative expenses also include professional and consulting services, headquarters facility costs, including rent, utilities, depreciation, amortization and maintenance, legal expenses related to intellectual property, litigation and corporate matters, insurance expense, expenses related to contract modifications or terminations, software expenses, expenses incurred to engage with patient advocacy organizations, and recruitment related expenses. We expect our general and administrative expenses to decrease in the future due to the termination of leased office facilities and associated asset depreciation, reductions in staff and reductions in professional and consulting services. We also expect to incur increased legal and professional fees in the near term in connection with the proposed Merger and related transaction activities.

Impairment of Long-Lived Assets

Impairment of long-lived assets consists of non-cash impairment charges recorded to our assets. We review long-lived assets, such as the right of use assets, or ROU assets, and property and equipment, for impairments when events or changes in circumstances indicate the carrying amount of the assets may not be recoverable. During the three and nine months ended September 30, 2026, we did not recognize impairment expenses.

During the nine months ended September 30, 2025, we recognized impairment expenses as a result of the announcement in January 2025 to reduce our workforce by 55% and cease our lab operations in Hopewell, New Jersey. We reassessed asset groups and evaluated such asset groups for impairment. We determined the laboratory equipment was a separate asset group based on management's implemented plans to sell the laboratory equipment and estimated the fair value of the laboratory equipment based on the estimated future cash flows from the sale of such equipment.

Net Gain on Lease Terminations

The net gain on lease terminations was a result of the Hopewell Lease Termination Agreement, for the laboratory lease agreement related to our laboratory facility in Hopewell, New Jersey and the 2005 Market Street Lease Termination Agreement, for our office space located in Philadelphia, Pennsylvania. As a result of the Hopewell Lease Termination Agreement and the 2005 Market Street Lease Termination Agreement, we recognized a net gain on the lease terminations comprised of a gain on the write-off of assets and liabilities for operating leases and a loss on the disposal of property and equipment.

Other Income (Expense), Net

Other income (expense), net consists of interest earned on our cash equivalents and marketable securities, amortization of premium and discount on our marketable securities, income from subleases, and the sale of certain tax credits.

Results of Operations

Comparison of the three months ended September 30, 2026 and 2025

The following table sets forth our results of operations for the three months ended September 30, 2026 and 2025:

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Research and Development Expenses

Research and development expenses decreased by $2.8 million to $1.5 million for the three months ended September 30, 2026 from $4.3 million for the three months ended September 30, 2025. The decrease was primarily due to the following:

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These decreases were partially offset by:

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General and Administrative Expenses

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General and administrative expenses decreased by $0.9 million to $3.4 million for the three months ended September 30, 2026 from $4.3 million for the three months ended September 30, 2025. The decrease was primarily due to the following:

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These decreases were partially offset by:

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Other Income (Expense), Net

Other income (expense), net decreased by $0.7 million to $0.2 million for the three months ended September 30, 2026 from $0.9 million for the three months ended September 30, 2025. The decrease was due to a $0.3 million decrease in interest income and a $0.4 million decrease in sublease income due to the 2005 Market Street Lease Termination Agreement.

Comparison of the nine months ended September 30, 2026 and 2025

The following table sets forth our results of operations for the nine months ended September 30, 2026 and 2025:

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Research and Development Expenses

Research and development expenses decreased by $9.0 million to $8.9 million for the nine months ended September 30, 2026 from $17.9 million for the nine months ended September 30, 2025. The decrease was primarily due to the following:

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General and Administrative Expenses

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General and administrative expenses increased by $0.1 million to $15.1 million for the nine months ended September 30, 2026 from $15.0 million for the nine months ended September 30, 2025. The increase was primarily due to the following:

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The increase was partially offset by:

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Impairment of Long-Lived Assets

During the nine months ended September 30, 2026, we did not record any impairment expense.

During the nine months ended September 30, 2025, we recorded $2.6 million of impairment expense related to laboratory equipment and certain other assets which were revalued and subsequently sold from the Hopewell laboratory space.

Net Gain on Lease Terminations

During the nine months ended September 30, 2026, we recorded a $2.6 million net gain on the termination of both the Hopewell Laboratory Lease Agreement and 2005 Market Street Lease Agreement. The net gain was comprised of a $6.6 million gain on the write-off of assets and liabilities for operating leases offset by a $4.0 million net loss on disposal of property and equipment.

During the nine months ended September 30, 2025, we did not record any lease termination gain or loss.

Other Income (Expense), Net

Other income (expense), net decreased by $1.5 million to $1.4 million for the nine months ended September 30, 2026 from $2.9 million for the nine months ended September 30, 2025. The decrease was due to a $1.0 million decrease in interest income and the amortization of premium and discount on our marketable securities and a $0.5 million decrease in sublease income due to the 2005 Market Street Lease Termination Agreement.

Liquidity and Capital Resources

Overview

As of September 30, 2026, we had $20.2 million in cash and cash equivalents and had an accumulated deficit of $724.9 million. We expect to continue to incur net losses and negative cash flows from operations for the foreseeable future. As of September 30, 2026, we do not expect our cash to be sufficient to fund our operating expenses and capital expenditure requirements for at least the twelve months following the date our consolidated financial statements are issued. As a result, substantial doubt exists about our ability to continue as a going concern within one year after the date that the consolidated financial statements are issued. Our ability to continue as a going concern will depend on our ability to complete the Merger (including the related Concurrent Financing) or otherwise obtain substantial additional funding. There can be no assurance that we will be able to complete the Merger or that Remix will be able to complete the Concurrent Financing on a timely basis, on acceptable terms, or at all.

Funding Requirements

Our primary use of cash is to fund operating expenses. Cash used to fund operating expenses is impacted by the timing of when we pay these expenses, as reflected in the change in our outstanding accounts payable, accrued expenses and prepaid expenses.

Because of the numerous risks and uncertainties associated with research, development and commercialization of pharmaceutical products, we are unable to estimate the exact amount of our operating capital requirements. Our future funding requirements will depend primarily on our ability to complete the proposed transaction with Remix.

We would need additional funds to meet operational needs and capital requirements for clinical trials, other research and development expenditures, and business development activities. We currently have no credit facility or committed sources of capital. Because of the numerous risks and uncertainties associated with the development and commercialization of our product candidates, we are unable to estimate the amounts of increased capital outlays and operating expenditures associated with future clinical studies.

If we do not complete the proposed transaction with Remix and until such time, if ever, as we can generate substantial product revenue, we expect to finance our operations through a combination of equity offerings, debt financings, collaborations, strategic alliances, reverse merger or other business combination transactions, and marketing, distribution or licensing arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, existing stockholders' ownership interest will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect existing stockholders' rights as common stockholders. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making acquisitions or capital expenditures or declaring dividends. If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or drug candidates, or grant licenses on terms that may not be favorable to us. If we pursue a reverse merger or other business combination transaction, we may be subject to significant transaction costs, our stockholders may experience substantial dilution, our management team may change, and we may not achieve the anticipated benefits of such a transaction.

On March 5, 2021, we entered into a Sales Agreement, or the Sales Agreement, with Cowen and Company, LLC, or Cowen, relating to the applicable terms of at-the-market equity offerings, or the ATM Facility, pursuant to which we may, but are not obligated to, offer and sell, from time to time, shares of our common stock with an aggregate offering price up to $125.0 million through Cowen, as sales agent in the ATM Facility. We issued 300,000 shares of common stock under the ATM Facility, resulting in net proceeds of $8.7 million, after deducting offering costs of $0.3 million in March 2024. As a result of our public float as of January 9, 2026, we are currently limited to $21.1 million in our capacity to offer and sell shares of our common stock under the Sales Agreement pursuant to our shelf registration statement on Form S-3, filed on March 4, 2024. As of September 30, 2026, $15.8 million of capacity remains available to be sold under the ATM Facility.

Cash Flows

The following table shows a summary of our cash flows for the periods indicated:

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Net Cash Provided by (Used in) Operating Activities

During the nine months ended September 30, 2026, we used $26.2 million of net cash in operating activities. Cash used in operating activities reflected a net loss of $20.1 million, net changes in our operating assets and liabilities of $5.1 million, and net non-cash adjustments of $1.0 million related to the net gain on lease terminations and disposal of property and equipment partially offset by depreciation, amortization, and share-based compensation. The primary uses

of cash were to fund our operations related to the development of our product candidates and the payment of the lease termination fees in connection with the Hopewell Lease Termination Agreement and the 2005 Market Street Lease Termination Agreement.

During the nine months ended September 30, 2025, we used $25.0 million of net cash in operating activities. Cash used in operating activities reflected a net loss of $32.5 million and a decrease in our operating assets of $1.8 million and non-cash charges of $5.7 million related to depreciation, amortization, share-based compensation, amortization of premium and discount, net, impairment of long-lived assets, and other non-cash items. The primary use of cash was to fund our operations related to the development of our product candidates.

Net Cash Provided by (Used in) Investing Activities

During the nine months ended September 30, 2026, we received de minimis cash proceeds related to the sale of property and equipment.

During the nine months ended September 30, 2025, we had sales and maturities of $39.0 million in marketable securities and received cash proceeds of $1.2 million related to the sale of property and equipment and certain other assets. We did not make any purchases of property and equipment for the nine months ended September 30, 2025.

Net Cash Provided by (Used in) Financing Activities

During the nine months ended September 30, 2026, we had no gross receipts or outflows of cash related to financing activities.

During the nine months ended September 30, 2025, we received de minimis proceeds from the issuance of common stock under the ESPP.

Contractual Obligations and Other Commitments

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Either we or Remix may terminate the Merger Agreement under certain circumstances, which would prevent the Merger from being consummated. If the Merger Agreement is terminated under certain circumstances, we may be required to pay Remix a termination fee of $1.5 million.

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Critical Accounting Policies and Estimates

During the nine months ended September 30, 2026, there were no material changes to our critical accounting policies and estimates from those described under the heading "Management's Discussion and Analysis of Financial Condition and Results of Operations-Critical Accounting Policies and Estimates" in our 2025 Annual Report filed on Form 10-K.

Recent Accounting Pronouncements

See Note 3 to our unaudited interim consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q for a description of recent accounting pronouncements applicable to our consolidated financial statements.