# Passage BIO, Inc.: Form 10-Q for the period ended Mar 31, 2026

- Company: [Passage BIO, Inc.](/companies/pasg.md) (CIK 1787297)
- Form: 10-Q
- Filed: 2026-05-12
- Accepted by EDGAR: May 12, 2026, 07:01 ET
- Period: 2026-03-31
- Accession: 0001104659-26-058987
- Inline XBRL: yes
- Main document: https://www.sec.gov/Archives/edgar/data/1787297/000110465926058987/pasg-20260331x10q.htm
- All documents and exhibits: https://www.sec.gov/Archives/edgar/data/1787297/000110465926058987/

## Figures reported in this filing

Standardized XBRL line items for the period ended 2026-03-31.

| Line item | Period | Value | XBRL concept |
| --- | --- | ---: | --- |
| Research and development | 3 months, 2026-01-01 to 2026-03-31 | $4.1m | us-gaap:ResearchAndDevelopmentExpense |
| Operating income | 3 months, 2026-01-01 to 2026-03-31 | −$8.2m | us-gaap:OperatingIncomeLoss |
| Net income | 3 months, 2026-01-01 to 2026-03-31 | −$7.6m | us-gaap:NetIncomeLoss |
| Diluted EPS | 3 months, 2026-01-01 to 2026-03-31 | −$2.36 | us-gaap:EarningsPerShareDiluted |
| Basic EPS | 3 months, 2026-01-01 to 2026-03-31 | −$2.36 | us-gaap:EarningsPerShareBasic |
| Diluted shares (weighted) | 3 months, 2026-01-01 to 2026-03-31 | 3,205,866 shares | us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding |
| Operating cash flow | 3 months, 2026-01-01 to 2026-03-31 | −$13.0m | us-gaap:NetCashProvidedByUsedInOperatingActivities |
| Cash and equivalents | at 2026-03-31 | $33.3m | us-gaap:CashAndCashEquivalentsAtCarryingValue |
| Current assets | at 2026-03-31 | $34.7m | us-gaap:AssetsCurrent |
| Total assets | at 2026-03-31 | $36.5m | us-gaap:Assets |
| Current liabilities | at 2026-03-31 | $20.1m | us-gaap:LiabilitiesCurrent |
| Total liabilities | at 2026-03-31 | $24.7m | us-gaap:Liabilities |
| Shareholders' equity | at 2026-03-31 | $11.8m | us-gaap:StockholdersEquity |

## Management's discussion and analysis

As filed, 51,757 characters.

*You should read the following discussion and analysis of our financial condition and results of operations in conjunction with our 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 focused on improving the lives of patients with neurodegenerative diseases. Our primary focus is the development and advancement of cutting-edge, one-time gene therapies designed to target critical underlying pathologies in these conditions. We believe we have developed a differentiated approach to developing treatments for central nervous system, or CNS, disorders that allows us to select and advance product candidates with a higher probability of technical and regulatory success.

Our lead clinical product candidate, PBFT02, seeks to elevate progranulin levels to enhance lysosomal function and slow disease progression across a variety of neurodegenerative diseases. PBFT02 is 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. The lead indication for PBFT02 is frontotemporal dementia, or FTD, caused by progranulin deficiency, or FTD-*GRN*. We believe this clinical product candidate has the potential to provide patients with significantly improved outcomes given the rigorous capsid and transgene selection process, and our chosen route of ICM administration, which provides the potential for enhanced benefits due to widespread vector delivery to the brain and spinal cord and an improved safety profile compared with systemic administration, due to the lower doses required.

We are currently studying PBFT02 in FTD-*GRN*, for which there are currently no approved disease-modifying therapies. In light of the FDA’s recent guidance that a randomized controlled registrational study is required for PBFT02 in FTD-*GRN* and the associated ethical, logistical, and financial challenges, we are evaluating potential next steps in the clinical development of PBFT02 in FTD-*GRN* and FTD-*C9orf72*. Third-party preclinical studies have shown that increased PGRN levels reduce the pathologic accumulation of TAR DNA binding protein 43, or TDP-43. TDP-43 pathology is a hallmark of multiple neurodegenerative conditions, including FTD due to mutations in the *C9orf72* gene, or FTD-*C9orf72*, approximately 95% of sporadic amyotrophic lateral sclerosis, or ALS, and approximately 50% of sporadic FTD. Additionally, we believe restoration of PGRN has the potential to modulate Alzheimer’s disease, or AD, in patients who are carriers of the PGRN-lowering *GRN* rs5848 single nucleotide polymorphism, or SNP. Individuals with this polymorphism have reduced PGRN levels and are at an increased risk for AD. We have received positive regulatory feedback on the clinical pathway to treating FTD-*C9orf72* patients and ALS patients with PBFT02. We have initiated clinical development of PBFT02 in FTD-*C9orf72* patients in the upliFT-D trial for this population.

We have a preclinical research program to develop a genetic medicine to treat Huntington’s disease through the Gemma Collaboration Agreement. Huntington’s disease, or HD, is an adult-onset, progressive neurodegenerative disease characterized by motor, cognitive, and behavioral deterioration, ultimately leading to death within approximately 15 to 20 years after symptom onset. There are currently no disease-modifying therapies approved for the treatment of HD, and we estimate the prevalence of HD in the United States and Europe is approximately 70,000, based on available literature.

We are also party to a series of sublicense agreements, as amended, with Gemma in connection with the outlicensing of three pediatric programs we had previously advanced to clinical stage development, collectively the Outlicensed Programs, and such agreements, the Amended Gemma Sublicenses. In addition, we entered into a Transition Services Agreement, as amended, with Gemma. We refer to the Amended Gemma Sublicenses, the Transition Services Agreement, and the Gemma Collaboration Agreement, collectively, as the Outlicense Transaction Agreements.

Prior to the execution of the Outlicense Transaction Agreements, we advanced our preclinical programs through our research collaboration with the Trustees of the University of Pennsylvania’s, or Penn’s, Gene Therapy Program, or GTP. This collaboration provided access to differentiated scientific expertise for the conduct of rigorous preclinical studies to generate promising product candidates. Gemma is comprised of a core research team from GTP and is continuing the same approach to preclinical development to support the continued development of our preclinical Huntington’s disease program.

### Our Pipeline

We have a gene therapy pipeline with the potential to address multiple neurodegenerative diseases. Our development programs consist of:

#### † US/EU prevalence per third-party sources

In addition to the indications above, we believe ALS and AD represent future potential pipeline expansion opportunities for PBFT02. However, as described above, we are currently evaluating potential next steps in the clinical development of PBFT02.

### PBFT02 for the Treatment of FTD-GRN

PBFT02 is a gene replacement therapy which utilizes an AAV1 capsid to deliver a functional copy of *GRN* encoding for PGRN, for the treatment of FTD-*GRN*. FTD-*GRN* is an inheritable form of FTD caused by reductions in PGRN production due to mutations in the *GRN* gene. PGRN is a complex and highly conserved protein with multiple roles in cell homeostasis, neurodevelopment, and inflammation. In FTD-*GRN*, PGRN deficiency results in lysosomal dysfunction, neuroinflammation, and neurodegeneration.

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 believe 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 have 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 are conducting our 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.*

In April 2026, we reported updated interim biomarker data from patients in our upliFT-D trial.

- **CSF and Plasma PGRN:** Dose 1 of PBFT02 (3.3e10 genome copies/g estimated brain weight, or 4.5e13 total genome copies) resulted in robust and durable increases in CSF PGRN levels, with concentrations increasing

from below 3.0 ng/mL at baseline to a mean of 12.4 ng/mL at one month (n=7), 19.4 ng/mL at six months (n=7), 22.8 ng/mL at 12 months (n=6), and 24.2 ng/mL at 18 months (n=3). These levels of CSF PGRN are higher than the range found in healthy adult controls of 3.3 to 8.2 ng/mL (mean=4.8 ng/mL; n=61). Dose 2 of PBFT02 (1.6e10 genome copies/g estimated brain weight, or 2.2e13 total genome copies) increased substantially from 1.5 ng/mL at baseline to 8.6 ng/mL at one month (n=2), above the upper limit of the range found in healthy adult controls, and increased to 22.6 ng/mL at six months (n=1), achieving comparable CSF PGRN levels as Dose 1 at the same time point. In contrast, following PBFT02 administration, plasma PGRN levels were unaltered, remaining similar to baseline concentrations and below mean levels found in healthy adult controls.

- **Whole Brain Atrophy:** PBFT02-treated patients with a global Clinical Dementia Rating, or CDR, score of 1 at baseline experienced a 64% reduction in whole brain atrophy at 12 months (n=2), on average, as compared to vMRI analysis of untreated global CDR 1 patients from the ALLFTD natural history data. PBFT02-treated global CDR 1 patients experienced 3.1% atrophy at 12 months (n=2), on average, compared to 8.7% atrophy at 12 months (n=7) in ALLFTD sample of global CDR 1 individuals.
- **Frontotemporal Cortex Atrophy:** PBFT02-treated patients with global CDR score of 1 at baseline experienced a 54% reduction in frontotemporal cortex atrophy at 12 months (n=2), on average, as compared to vMRI analysis of untreated global CDR 1 patients from the ALLFTD natural history data. PBFT02-treated global CDR 1 patients experienced 4.6% atrophy at 12 months (n=2), on average, compared to 9.9% atrophy at 12 months (n=7) in ALLFTD sample of global CDR 1 individuals
- **Plasma Neurofilament Light Chain, or NfL:** PBFT02-treated patients showed an average reduction of 1.0 pg/mL in plasma NfL levels at 12-months (n=6) compared to baseline. In contrast, analysis of untreated symptomatic FTD-*GRN* patients from the ALLFTD natural history data showed an average increase of 13.5 pg/mL at 12 months (n=7) compared to baseline.

As of our March 2026 data disclosure, interim safety highlights from PBFT02 (n=10 FTD-*GRN* patients and n=1 FTD-*C9orf72* patient) included:

- Eight patients experienced a collective total of 32 treatment emergent adverse events, or TEAEs, considered related to PBFT02.
- Two patients experienced a total of three serious TEAE considered related to PBFT02. These included venous sinus thrombosis (2 patients) and hepatoxicity (1 patient). These serious TEAE all occurred at Dose 1, were asymptomatic and responded to treatment.
- One patient experienced one serious TEAE of pulmonary embolism in the setting of a concurrent systemic infection six weeks after receiving PBFT02 considered unrelated to PBFT02.
- No evidence of thrombotic angiopathy, dorsal root ganglion toxicity, and no complications during ICM administration were observed across any of the eleven treated patients.

We have completed the dosing of Cohorts 1 and 2 in the upliFT-D trial in July 2025. Cohort 1 consists of 5 patients who received Dose 1 of PBFT02, and Cohort 2 consists of 4 patients, split equally between Dose 1 and Dose 2 of PBFT02. Cohorts 1 and 2 included participants with a global Clinical Dementia Rating, or CDR, plus National Alzheimer’s Coordinating Center with Frontotemporal Lobar Degeneration, or NACC FTLD, score of 1 or 2 at baseline. The global CDR rating is scored from 0 (normal/asymptomatic) to 3 (severe).

In advance of enrolling Cohort 3, which we expected to consist of 10 FTD-*GRN* patients receiving Dose 2 of PBFT02, we amended the upliFT-D clinical trial protocol to introduce a short course of low dose prophylactic anticoagulation. We also amended the protocol to exclude patients with a global CDR score of 2 (moderate) at baseline and include only patients with global CDR scores of 0.5 (prodromal) or 1 (mild) at baseline. We have initiated enrollment and dosing patients in Cohort 3 across our global trial sites.

In September 2025, we completed a Type D Chemistry, Manufacturing, and Controls meeting with the FDA and aligned on key elements of the analytical plan to establish comparability of product manufactured with our high-productivity, suspension-based PBFT02 manufacturing process to the current product being used in our ongoing clinical trial.

In April 2026, we disclosed feedback from a Type C meeting with the FDA regarding key elements of a future registrational trial design of PBFT02 for FTD-*GRN* in which FDA indicated that a randomized controlled registrational study design is required for PBFT02 in this indication. In light of the ethical, logistical, and financial challenges posed

by a randomized controlled registrational trial, we are evaluating potential next steps in the clinical development of

PBFT02 in FTD-*GRN* and FTD-*C9orf72* in the upliFT-D trial.

### PBFT02 for the Treatment of FTD-C9orf72 and ALS

We have initiated an evaluation of PBFT02 for the treatment of additional adult neurodegenerative diseases where we believe elevated PGRN levels could provide benefits. This approach stems 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 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 anticipate that elevating neuronal PGRN levels in diseases with TDP-43 pathology may provide significant benefits to patients. We have 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.*

We received positive regulatory feedback on the clinical pathway to treating FTD-*C9orf72* with PBFT02 in the ongoing upliFT-D trial, and we have planned for Cohorts 4 and 5 of upliFT-D to consist of three to five symptomatic FTD patients with *C9orf72* gene mutations who will initially receive Dose 2 PBFT02. We have initiated enrollment and dosing patients in Cohort 4 across our global trial sites.

Similarly, we received positive regulatory feedback on the clinical pathway to treating ALS with PBFT02 which we believe may represent a future pipeline opportunity.

### PBFT02 for the Treatment of AD

We also believe that elevating PGRN levels has the potential to improve the course of 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. This may represent a future pipeline opportunity for PBFT02, however, we are currently evaluating potential next steps in the clinical development of PBFT02 for the treatment of AD.

### Clinical Supply

Through our partners, we have manufactured the PBFT02 clinical supply to support completion of the ongoing Phase 1/2 clinical trial in FTD-*GRN* and FTD-*C9orf72*. We are currently evaluating potential next steps in the clinical development of PBFT02 in FTD-*GRN.*

### Active Research Programs

We have a preclinical research program through the Gemma Collaboration Agreement to develop a genetic medicine to treat HD.

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.

Our approach is 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.

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

### Business Overview

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 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 $7.6 million and $15.4 million for the three months ended March 31, 2026 and 2025, respectively. As of March 31, 2026, we had an accumulated deficit of $712.3 million. Our primary use of cash is to fund operating expenses, which consist primarily of research and development expenditures and general and administrative expenditures. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our current or future product candidates. We expect to continue to incur significant expenses and operating losses for the foreseeable future as we advance our product candidates through all stages of development and clinical trials and, ultimately, seek regulatory approval. In addition, if we obtain marketing approval for any of our product candidates, we expect to incur significant commercialization expenses related to product manufacturing, marketing, sales and distribution. Our net losses may fluctuate significantly from quarter to quarter and year to year, depending on the timing of our clinical trials and our expenditures on other research and development activities.

As of March 31, 2026, we had cash and cash equivalents of $33.3 million, which we do not expect to be sufficient to meet our capital requirements over the next 12 months.

We will need to raise substantial additional capital to support our continuing operations and pursue our growth strategy. Until such time as we can generate significant revenue from product sales, if ever, we plan to finance our operations through the sale of equity, debt financings or other capital sources, which may include collaborations with other companies or other strategic transactions. There are no assurances that we will be successful in obtaining an adequate level of financing as and when needed to finance our operations on terms acceptable to us or at all. Any failure to raise capital as and when needed could have a negative impact on our financial condition and on our ability to pursue our business plans and strategies. If we are unable to secure adequate additional funding, we may have to significantly delay, scale back or discontinue the development and commercialization of one or more product candidates or delay our pursuit of potential in-licenses or acquisitions.

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 financial statements included in this Quarterly Report on Form 10-Q are issued.

On April 20, 2026, we announced that we have initiated a review of strategic alternatives to maximize shareholder value. These strategic alternatives may include, but are not limited to, merger or acquisition transactions, a reverse merger, a sale of assets of the Company, strategic partnerships, licensing opportunities, or other potential paths. We do not intend to provide updates on the strategic review until our board of directors approves a specific action or otherwise determines that disclosure is appropriate or required. There can be no assurance that the process will result in any such transaction.

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 should be substantially complete in the second and third quarters of 2026. We estimate the aggregate severance and related costs for the Restructuring Plan will be approximately $3.3 million, which will be recorded primarily in the second quarter of 2026. These estimates are subject to a number of assumptions, and actual results may differ materially. We may also incur additional costs not currently contemplated due to events that may occur as a result of, or that are associated with, the Restructuring Plan as well as our review of strategic alternatives.

### 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 FTD, 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.

#### 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.

The Gemma Collaboration Agreement requires that we make payments of up to (i) $16.5 million per product candidate in the aggregate for Huntington’s disease and any future CNS indications available to us under our four options and (ii) $39.0 million per product candidate in the aggregate arising from the research program for TLE. 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.

Upon successful commercialization of a product using the licensed technology, we are obligated to pay to Gemma, 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, we are obligated to pay to Gemma a percentage of sublicensing income, ranging from the mid-single digits to low double digits, for sublicenses under the Gemma Collaboration 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.

If we were to exercise any of the four options, we would owe Gemma a non-refundable aggregate fee of $1.0 million per product indication, with $0.5 million due upfront and another $0.5 million fee owed upon a further developmental milestone.

#### 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 $7.5 million was previously received, $2.5 million of which was due in May 2025, and $5.0 million of which was due in March 2026; (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 March 31, 2026, we have collected $7.5 million in initial payments and $4.8 million in transition services payments under these agreements. In addition, we have applied $1.5 million in amounts owed to Gemma for the Huntington’s disease program against amounts due to us for transition services.

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

#### Catalent

We have 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 remain in effect until November 6, 2030, and establish 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. The limited exclusive relationship under the Amended Catalent Agreements converts to a non-exclusive relationship (i) in the event Catalent fails 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, if such events occur, 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 are required to make payment of $0.9 million to Catalent which is accrued as of March 31, 2026.

### 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:

- personnel expenses, including salaries, benefits and share-based compensation expense for employees engaged in research and development functions;
- expenses incurred at and for our lab facilities, including rent, utilities, depreciation, amortization and maintenance;
- expenses incurred to conduct the necessary preclinical studies and clinical trials required to obtain regulatory approval, including payments to clinical research organizations, or CROs, and payments to Gemma and Penn for preclinical research and development;
- expenses and fees paid to consultants who assist with research and development activities; and

expenses incurred under agreements with contract development and manufacturing organizations, or CDMOs, including the cost of acquiring and manufacturing preclinical trial and clinical trial materials.

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.

In April 2026, we announced we are evaluating potential next steps in the clinical development of PBFT02, and in connection with our review of strategic alternatives, we announced a restructuring of our workforce to decrease operating expenses by approximately 75%. As a result, we expect our research and development expenses to decrease in the near future.

#### 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. In connection with our review of strategic alternatives, we announced a restructuring of our workforce to decrease operating expenses by approximately 75%. As a result, we expect our general and administrative expenses to decrease in the near future.

#### 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 months ended March 31, 2026, we did not recognize impairment expenses.

During the three months ended March 31, 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 Termination

The net gain on lease termination was a result of the Hopewell Lease Termination Agreement, for the laboratory lease agreement related to our laboratory facility in Hopewell, New Jersey. As a result of the Hopewell Lease Termination Agreement, we recognized a net gain on the lease termination 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 March 31, 2026 and 2025

The following table sets forth our results of operations for the three months ended March 31, 2026 and 2025:

*(in thousands)*

| ​ ​ ​ Operating expenses: | ​ ​ ​ ​ ​ ​ | ​ ​ Three months ended March 31, 2026 ​ ​ | ​ ​ ​ ​ | ​ ​ 2025 ​ ​ | ​ ​ ​ ​ ​ ​ | ​ ​ ​ ​ ​ ​ Change ​ ​ |
| --- | --- | ---: | --- | ---: | --- | ---: |
| Research and development | ​ | $4,093 | ​ | $7,737 | ​ | $(3,644) |
| General and administrative | ​ | 4,787 | ​ | 6,085 | ​ | (1,298) |
| Impairment of long-lived assets | ​ | ​ — | ​ | 2,637 | ​ | ​ (2,637) |
| Net gain on lease termination | ​ | ​ (633) | ​ | — | ​ | ​ (633) |
| Loss from operations | ​ | (8,247) | ​ | (16,459) | ​ | 8,212 |
| Other income (expense), net | ​ | 688 | ​ | 1,054 | ​ | (366) |
| Net loss | ​ | $(7,559) | ​ | $(15,405) | ​ | $7,846 |

#### Research and Development Expenses

Research and development expenses decreased by $3.6 million to $4.1 million for the three months ended March 31, 2026 from $7.7 million for the three months ended March 31, 2025. The decrease was primarily due to the following:

- a decrease of $2.1 million in wages and benefits due to a lower headcount following our restructuring in January 2025;
- a decrease of $1.0 million in facility and other expenses related to decreased rent expenses in connection with the Hopewell Lease Termination Agreement;
- a decrease of $0.6 million in clinical operations expenses due to decreased activity in the GM1 program partially offset by increased activity supporting the FTD program; and
- a decrease of $0.1 million in share-based compensation expense related to reductions in headcount.

These decreases were partially offset by:

- an increase of $0.2 million in preclinical research expenses related to Huntington’s disease program expenses.

#### General and Administrative Expenses

General and administrative expenses decreased by $1.3 million to $4.8 million for the three months ended March 31, 2026 from $6.1 million for the three months ended March 31, 2025. The decrease was primarily due to the following:

- a decrease of $0.9 million and $0.2 million in wages and benefits and share-based compensation expense, respectively, related to reductions in headcount; and
- a decrease of $0.3 million in facility and other expenses.

These decreases were partially offset by:

- an increase of $0.1 million in professional fees.

#### Impairment of Long-Lived Assets

During the three months ended March 31, 2026, we did not record any impairment expense.

During the three months ended March 31, 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 Termination

During the three months ended March 31, 2026, we recorded a $0.6 million net gain on the termination of the Hopewell Laboratory Lease Agreement. The net gain was comprised of a $3.8 million gain on the write-off of assets and liabilities for operating leases offset by a $3.2 million net loss on disposal of property and equipment.

During the three months ended March 31, 2025, we did not record any lease termination gain or loss.

#### Other Income (Expense), Net

Other income (expense), net decreased by $0.4 million to $0.7 million for the three months ended March 31, 2026 from $1.1 million for the three months ended March 31, 2025. The decrease was due to a $0.4 million decrease in the amortization of premium and discount on our marketable securities.

### Liquidity and Capital Resources

#### Overview

As of March 31, 2026, we had $33.3 million in cash and cash equivalents and had an accumulated deficit of $712.3 million.

#### 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 on many factors, including, but not limited to:

- the scope, timing, progress and results of discovery, preclinical development, laboratory testing and clinical trials for our product candidates;
- the expenses of manufacturing our product candidates for clinical trials and in preparation for marketing approval and commercialization;
- the extent to which we enter into collaborations or other arrangements with additional third parties in order to further develop our product candidates;
- the expenses of preparing, filing and prosecuting patent applications, maintaining and enforcing our intellectual property rights and defending intellectual property-related claims;
- the expenses and fees associated with the discovery, acquisition or in-license of additional product candidates or technologies;
- the expenses related to general and administrative functions to support our product candidates;
- our ability to establish additional collaborations on favorable terms, if at all;
- the expenses required to scale up our clinical, regulatory and manufacturing capabilities;
- the expenses of future commercialization activities, if any, including establishing sales, marketing, manufacturing and distribution capabilities, for any of our product candidates for which we receive marketing approval; and
- revenue, if any, received from commercial sales of our product candidates, should any of our product candidates receive marketing approval.

We will 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 our current and anticipated clinical studies.

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. If we are unable to raise additional funds through equity or debt financings or other arrangements when needed, we may be required to delay, limit, further reduce or terminate our research, product development or future commercialization efforts, or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

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 March 31, 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:

*(in thousands)*

| ​ ​ ​ | ​ ​ ​ ​ | ​ ​ Three months ended March 31, 2026 | ​ ​ | ​ ​ 2025 |
| --- | --- | ---: | --- | ---: |
| Cash provided by (used in) operating activities | ​ ​ ​ | $(12,987) | ​ ​ ​ | $(13,847) |
| Cash provided by (used in) investing activities | ​ | 20 | ​ | 39,631 |
| Cash provided by (used in) financing activities | ​ | — | ​ | — |
| Net increase (decrease) in cash and cash equivalents | ​ | $(12,967) | ​ | $25,784 |

#### Net Cash Provided by (Used in) Operating Activities

During the three months ended March 31, 2026, we used $13.0 million of net cash in operating activities. Cash used in operating activities reflected a net loss of $7.6 million and a decrease in our operating assets of $5.5 million offset by non-cash charges of $0.1 million related to depreciation, amortization, share-based compensation, loss recognized on disposal of long-lived assets, and other non-cash items. 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 fee in connection with the Hopewell Lease Termination Agreement.

During the three months ended March 31, 2025, we used $13.8 million of net cash in operating activities. Cash used in operating activities reflected a net loss of $15.4 million and a decrease in our operating assets of $2.2 million, partially offset by non-cash charges of $3.8 million related to depreciation, amortization, share-based compensation, amortization of premium and discount, net, and impairment of long-lived assets. 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 three months ended March 31, 2026, we received de minimis cash proceeds related to the sale of property and equipment.

During the three months ended March 31, 2025, we had sales and maturities of $39.0 million in marketable securities and received cash proceeds of $0.6 million related to the sale of property and equipment and certain other assets.

#### Net Cash Provided by (Used in) Financing Activities

During the three months ended March 31, 2026 and 2025, we had no gross receipts or outflows of cash related to financing activities.

### Contractual Obligations and Other Commitments

We lease approximately 37,000 square feet of office space in Philadelphia, Pennsylvania, or the 2005 Market Street Lease Agreement. The lease will expire in December 2031. We have an option to extend the term of the lease by up to two additional five-year terms. Our sublease agreements do not relieve us from our primary obligations under the 2005 Market Street Lease Agreement, however, we do expect cash inflows from the agreements to partially offset our future obligations for the duration of the sublease agreements.

The aggregate estimated rent payments due over the remaining terms of our leases are $7.4 million.

Under the exclusive relationship under the Amended Catalent Agreements, following certain conditional events related to the divestiture by us of either FTD or GM1, 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 outlicense 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 are required to make payment of $0.9 million to Catalent which has been accrued as of March 31, 2026.

These contractual obligations and commitments are associated with contracts that are enforceable and legally binding and that specify all significant terms, including fixed or minimum services to be used, fixed, minimum or variable price provisions, and the approximate timing of the actions under the contracts. Payments due upon cancellation consisting only of payments for services provided or expenses incurred, including noncancelable obligations of our service providers, up to the date of cancellation are not included as the amount and timing of such payments are not known.

The contractual obligations and commitments above do not include any potential milestone or royalty payments that we may be required to make under the Penn License Agreement. Under the Amended Gemma Sublicenses, Gemma will be responsible for all potential milestone and royalty payments to Penn for the Outlicensed Programs.

The contractual obligations and commitments above do not include any potential milestone or royalty payments that we may be required to make under the Gemma Collaboration Agreement.

### Critical Accounting Policies and Estimates

During the three months ended March 31, 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 financial statements included elsewhere in this Quarterly Report on Form 10-Q for a description of recent accounting pronouncements applicable to our financial statements.

## Controls and procedures

As filed, 1,711 characters.

### Evaluation of Disclosure Controls and Procedures

As of March 31, 2026, management, with the participation of our Principal Executive Officer and Principal Financial and Accounting Officer, performed an evaluation of the effectiveness of our disclosure controls and procedures as defined in Rules 13a-15(e) and 15d-15(e) of the Securities Exchange Act of 1934, as amended, or the Exchange Act. Our disclosure controls and procedures are designed to ensure that information required to be disclosed in the reports we file or submit under the Exchange Act is recorded, processed, summarized, and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to our management, including the Principal Executive Officer and Principal Financial and Accounting Officer, to allow timely decisions regarding required disclosures. Any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objective and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on this evaluation, our Principal Executive Officer and Principal Financial and Accounting Officer concluded that, as of March 31, 2026, our disclosure controls and procedures were effective at a reasonable assurance level.

### Changes in Internal Control Over Financial Reporting

There were no changes in our internal control over financial reporting that occurred during the quarter ended March 31, 2026 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

## Risk factors

As filed, 4,411 characters.

In addition to the other information set forth in this report, you should carefully consider the factors discussed in Part I, “Item 1A. Risk Factors” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, as filed with the SEC on March 3, 2026, which could materially affect our business, financial condition or future results. These disclosures reflect our beliefs and opinions as to factors that could materially and adversely affect the Company and its securities in the future. References to past events are provided by way of example only and are not intended to be a complete listing of such events or a representation as to whether or not such factors or similar events have occurred in the past or their likelihood of occurring in the future. The risks described in our Annual Report on Form 10-K, for the fiscal year ended December 31, 2025, as filed with the SEC on March 3, 2026, may not be the only risks facing the Company. Additional risks and uncertainties not currently known to the Company or that the Company currently deems to be immaterial also may materially adversely affect the Company’s business, financial condition and/or operating results.

Except as set forth below, there were no material changes to the risk factors previously disclosed in our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, as filed with the SEC on March 3, 2026.

***If our continued exploration of strategic alternatives is unsuccessful, our financial condition and results of operations may be materially adversely affected.***

On April 20, 2026, we announced that we have initiated a review of strategic alternatives to maximize shareholder value. These strategic alternatives may include, but are not limited to, merger or acquisition transactions, a reverse merger, a sale of assets of the Company, strategic partnerships, licensing opportunities, or other potential paths. The strategic review is underway. We do not intend to provide updates on the strategic review until our board of directors approves a specific action or otherwise determines that disclosure is appropriate or required. There can be no assurance that the process will result in any such transaction. Any potential strategic alternative would be dependent on a number of factors that may be beyond our control, including, among other things, market conditions, industry trends, regulatory approvals, and the availability of financing for a potential transaction on reasonable terms. We may incur substantial expenses associated with identifying, evaluating, and negotiating potential strategic alternatives. Any potential transaction or other strategic alternative, if consummated, may not provide greater value to our stockholders than that reflected in the current price of our common stock. In addition, perceived uncertainties related to our future may result in the loss of potential business opportunities and volatility in the market price of our common stock.

***There is substantial doubt about our ability to continue as a going concern, which may hinder our ability to obtain further financing.***

Our financial statements are prepared using the generally accepted accounting principles applicable to a going concern, which contemplates the realization of assets and liquidation of liabilities in the normal course of business. However, as shown in our financial statements for the year ended December 31, 2025, included in our Annual Report on Form 10-K for the year ended December 31, 2025, and the interim financial statements included in this Report, we have sustained substantial recurring losses from operations. In addition, we have used, rather than provided, cash in our operations. As of March 31, 2026, we had cash and cash equivalents of approximately $33.3 million. The above conditions raise substantial doubt about our ability to continue as a going concern within one year after the date that our financial statements in this Report are issued. Our financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts and classification of liabilities that might be necessary should we be unable to continue in existence. Uncertainty concerning our ability to continue as a going concern, among other factors, may hinder our ability to obtain future financing or result in any strategic transaction.

Filed May 12, 2026.
Source: SEC EDGAR, the filing index for accession 0001104659-26-058987. Last ingested by Listed: Nov 6, 2026, 11:01 ET. No prices; not investment advice.