Fulfilling the Promise of Genetic Medicines for Central Nervous System Disorders Corporate Presentation November 2022 NASDAQ GS: PASG 2 Forward-Looking Statement This presentation includes "forward-looking statements" within the meaning of, and made pursuant to the safe harbor provisions of, the Private Securities Litigation Reform Act of 1995, including, but not limited to: our expectation about timing and execution of anticipated milestones, including our planned progress of clinical trials and the availa ...

Passage Bio, Inc. (NASDAQ:PASG) Q3 2022 Earnings Conference Call November 10, 2022 8:30 AM ET Company Participants Stuart Henderson - VP, Corporate Development and Investor Relations William Chou - Chief Executive Officer Mark Forman - Chief Medical Officer Simona King - Chief Financial Officer Conference Call Participants Brendan Smith - Cowen Neena Bitritto-Garg - Citi Laura Chico - Wedbush Danielle Brill - Raymond James Yun Zhong - BTIG Operator Good morning and welcome to the Passage Bio Third Quarter ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission File Number: 001-39231 PASSAGE BIO, INC. (Exact Name of Registrant as Specified in its Charter) Delaware ...

Pipeline and Programs - Passage Bio is developing transformative therapies for CNS disorders, targeting both rare and large patient populations[5] - The company's pipeline includes programs for GM1 gangliosidosis (PBGM01), Krabbe disease (PBKR03), metachromatic leukodystrophy (PBML04), and frontotemporal dementia (PBFT02)[5] - PBGM01 targets GM1 gangliosidosis, a rare pediatric disease with an incidence of approximately 1 per 100,000 live births worldwide[11] - PBKR03 addresses Krabbe disease, another devastating pediatric condition with an incidence of about 26 per 1 million live births worldwide[33] - PBFT02 is focused on frontotemporal dementia (FTD-GRN), a rare adult disease with an estimated U S prevalence of approximately 3,000 to 6,000 patients[40] - PBML04 targets metachromatic leukodystrophy (MLD), a rare pediatric disease with an incidence of approximately 1 per 100,000 live births worldwide[47] Clinical Trial Updates - Initial safety and biomarker data from Cohorts 2 & 3 of the PBGM01 trial were expected in the second half of 2022[16] - Initial safety and biomarker data from a subset of Cohort 1 in the PBKR03 (GALax-C) trial were expected by the end of 2022[38] - First patient dosing in the Phase 1/2 trial for PBFT02 was expected in mid-2022[42] - An IND clearance was obtained from the FDA in Q2 2022 for PBML04[50, 59] Financial Status - The company reported a cash balance of $239 million as of June 30, 2022, which is expected to fund operations into Q2 2024[59]

Financial Data and Key Metrics Changes - The company ended Q2 2022 with approximately $239.3 million in cash, cash equivalents, and marketable securities, down from $267.1 million as of March 31, 2022, indicating a decrease in cash reserves [27] - R&D expenses were $26.8 million for Q2 2022, a decrease from $33.1 million in the same quarter of 2021, primarily due to a reduction in clinical manufacturing expenses [28] - G&A expenses were $13 million for Q2 2022, down from $15.4 million in Q2 2021, mainly due to a reduction in personnel-related expenses [29] - The net loss for Q2 2022 was $39.5 million, compared to a net loss of $48.4 million in Q2 2021, reflecting an improvement in financial performance [30] Business Line Data and Key Metrics Changes - The company is advancing three ongoing clinical programs, with significant progress in the Imagine-1 trial for GM1 gangliosidosis, now recruiting for the final cohort [6][7] - The PBKR03 program for early infantile Krabbe disease is actively recruiting patients, with initial safety and biomarker data expected by the end of 2022 [20][22] - The PBFT02 program for frontotemporal dementia is preparing to dose the first patient shortly, with ongoing patient identification efforts [23][24] Market Data and Key Metrics Changes - The company has established a global network of trial sites across the United States, Brazil, Canada, the UK, Israel, and the Netherlands to enhance patient recruitment [10] - Increased genetic testing among frontotemporal dementia patients has been observed, aiding in patient identification for clinical trials [10][45] Company Strategy and Development Direction - The company aims to develop transformative therapies for CNS disorders with limited or no approved treatment options, focusing on advancing clinical programs and achieving key milestones [6][32] - The company is evaluating its financial situation and prioritizing assets for clinical development, indicating a strategic approach to resource allocation [37] Management's Comments on Operating Environment and Future Outlook - Management expressed confidence in achieving several important milestones in the coming months, including reporting initial data from ongoing clinical trials [32] - The company remains focused on managing cash carefully to ensure the delivery of meaningful clinical milestones [27][32] Other Important Information - The FDA cleared the IND application for the PBML04 program for metachromatic leukodystrophy, marking the company's fourth consecutive IND clearance [7][26] - The company has added Michael Kamarck, PhD, to its Board of Directors, bringing extensive biopharmaceutical experience [11] Q&A Session Summary Question: Will the initial Krabbe and GM1 data be released through a press release or a medical meeting? - The company is evaluating the best way to release the data, considering both scientific conferences and press releases [36] Question: Can you expand on the decision for clinical development for MLD? - The decision is based on evaluating the current financial situation and prioritizing assets rather than issues with the drug itself [37] Question: What safety events were observed in the initial patient dosed with PBKR03? - The first patient developed acute hydrocephalus but is currently stable after treatment, and additional safety monitoring has been implemented [41] Question: What is the status of patient recruitment for FTD? - Recruitment challenges are multifactorial, including patient identification and competition with other trials, but efforts are ongoing to improve throughput [49] Question: What is the status of the CEO search? - The Board is actively engaged in a public search for a new CEO and is making good progress [47]

PART I. FINANCIAL INFORMATION [Interim Financial Statements (Unaudited)](index=5&type=section&id=Item%201.%20Interim%20Financial%20Statements%20(Unaudited)) Unaudited interim financial statements for June 30, 2022, reveal a net loss, accumulated deficit, and decreased total assets [Balance Sheets](index=5&type=section&id=Balance%20Sheets) Balance sheets as of June 30, 2022, show decreased total assets to $299.4 million and increased total liabilities to $51.4 million Balance Sheet Summary (in thousands) | Account | June 30, 2022 | December 31, 2021 | | :--- | :--- | :--- | | Cash and cash equivalents | $91,129 | $128,965 | | Marketable securities | $148,121 | $186,808 | | **Total Assets** | **$299,416** | **$355,076** | | Total current liabilities | $27,133 | $29,498 | | **Total Liabilities** | **$51,370** | **$36,419** | | **Total Stockholders' Equity** | **$248,046** | **$318,657** | [Statements of Operations and Comprehensive Loss](index=6&type=section&id=Statements%20of%20Operations%20and%20Comprehensive%20Loss) Statements of operations report a net loss of $39.5 million for Q2 2022 and $82.4 million for H1 2022, primarily due to lower R&D expenses Operating Results (in thousands, except per share data) | Metric | Three Months Ended June 30, 2022 | Three Months Ended June 30, 2021 | Six Months Ended June 30, 2022 | Six Months Ended June 30, 2021 | | :--- | :--- | :--- | :--- | :--- | | Research and development | $26,821 | $33,112 | $53,034 | $58,082 | | General and administrative | $12,991 | $15,422 | $28,090 | $27,886 | | Loss from operations | $(39,812) | $(48,534) | $(82,624) | $(87,468) | | **Net loss** | **$(39,542)** | **$(48,435)** | **$(82,353)** | **$(87,317)** | | Net loss per share | $(0.73) | $(0.90) | $(1.52) | $(1.66) | [Statements of Stockholders' Equity](index=7&type=section&id=Statements%20of%20Stockholders'%20Equity) Stockholders' equity decreased to $248.0 million by June 30, 2022, primarily due to the **$82.4 million net loss** - The primary driver for the reduction in stockholders' equity during the first six months of 2022 was the **net loss of $82.4 million**[22](index=22&type=chunk)[23](index=23&type=chunk) [Statements of Cash Flows](index=11&type=section&id=Statements%20of%20Cash%20Flows) Cash flows for H1 2022 show **$70.8 million net cash used in operations**, leading to a **$37.8 million net decrease** in cash Cash Flow Summary (in thousands) | Activity | Six Months Ended June 30, 2022 | Six Months Ended June 30, 2021 | | :--- | :--- | :--- | | Net cash used in operating activities | $(70,794) | $(55,048) | | Net cash provided by (used in) investing activities | $33,315 | $(30,654) | | Net cash provided by financing activities | $(357) | $166,157 | | **Net increase (decrease) in cash** | **$(37,836)** | **$80,455** | | Cash and cash equivalents at end of period | $91,129 | $215,457 | [Notes to Unaudited Interim Financial Statements](index=12&type=section&id=Notes%20to%20Unaudited%20Interim%20Financial%20Statements) Notes detail the company's CNS therapy focus, **$438.6 million accumulated deficit**, sufficient cash for 12 months, and a patent claim - The company is a clinical-stage genetic medicines company focused on developing therapies for CNS disorders through a strategic research collaboration with the University of Pennsylvania's Gene Therapy Program (GTP)[31](index=31&type=chunk) - As of June 30, 2022, the company had an **accumulated deficit of $438.6 million** and expects existing cash to fund operations for at least the next twelve months[32](index=32&type=chunk)[36](index=36&type=chunk) - The company has an annual funding commitment of **$5.0 million to Penn** and an annual minimum commitment of **$10.6 million to Catalent** for manufacturing[78](index=78&type=chunk)[91](index=91&type=chunk) - REGENXBIO Inc. claims the company's use of the AAVhu68 capsid infringes its licensed patents, a claim the company believes it has valid defenses against[94](index=94&type=chunk) [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=32&type=section&id=Item%202.%20Management's%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Management discusses the CNS gene therapy pipeline, a reduced net loss of **$82.4 million** for H1 2022, and a cash runway into Q2 2024 - The company is advancing a portfolio of gene therapies for CNS disorders, with three programs in clinical trials: PBGM01, PBFT02, and PBKR03[113](index=113&type=chunk)[115](index=115&type=chunk)[119](index=119&type=chunk)[123](index=123&type=chunk) - In March 2022, the company implemented a **13% workforce reduction** and prioritized R&D programs to extend its cash runway[142](index=142&type=chunk) Comparison of Operating Results (in thousands) | Period | Research & Development Expense | General & Administrative Expense | Net Loss | | :--- | :--- | :--- | :--- | | **Q2 2022** | $26,821 | $12,991 | $(39,542) | | **Q2 2021** | $33,112 | $15,422 | $(48,435) | | **H1 2022** | $53,034 | $28,090 | $(82,353) | | **H1 2021** | $58,082 | $27,886 | $(87,317) | - As of June 30, 2022, the company had **$239.3 million in cash, cash equivalents, and marketable securities**, expected to fund operations into the second quarter of 2024[143](index=143&type=chunk)[177](index=177&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=53&type=section&id=Item%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) The company states this item is not applicable, indicating no significant exposure to market risks requiring disclosure - This section is not applicable to the company for the reporting period[197](index=197&type=chunk) [Controls and Procedures](index=54&type=section&id=Item%204.%20Controls%20and%20Procedures) Management concluded disclosure controls and procedures were effective as of June 30, 2022, with no material changes to internal control over financial reporting - Disclosure controls and procedures were effective as of June 30, 2022, as concluded by the Interim Principal Executive Officer and Principal Financial and Accounting Officer[198](index=198&type=chunk) - No material changes occurred in internal control over financial reporting during the quarter ended June 30, 2022[199](index=199&type=chunk) PART II. OTHER INFORMATION [Legal Proceedings](index=55&type=section&id=Item%201.%20Legal%20Proceedings) The company is not currently a party to any legal proceedings that would materially adversely affect its business - The company is not presently a party to any legal proceedings that would materially and adversely affect its business[202](index=202&type=chunk) [Risk Factors](index=55&type=section&id=Item%201A.%20Risk%20Factors) Key risks include operating losses, funding needs, clinical trial dependence, third-party reliance, manufacturing delays, competition, and intellectual property claims - The company has a history of operating losses, with a **$438.6 million accumulated deficit** as of June 30, 2022, necessitating additional funding[208](index=208&type=chunk)[214](index=214&type=chunk) - The business depends on advancing product candidates through a lengthy, expensive clinical development process with uncertain outcomes, especially for novel gene therapies[228](index=228&type=chunk)[234](index=234&type=chunk)[249](index=249&type=chunk) - The company relies exclusively on its collaboration with the University of Pennsylvania for preclinical R&D and on third-party manufacturers like Catalent for clinical supply[281](index=281&type=chunk)[321](index=321&type=chunk) - The company faces a patent infringement claim from Regenxbio Inc. regarding its AAVhu68 capsid, potentially requiring a license or halting development if successful[377](index=377&type=chunk)[378](index=378&type=chunk) [Unregistered Sales of Equity Securities and Use of Proceeds](index=165&type=section&id=Item%202.%20Unregistered%20Sales%20of%20Equity%20Securities%20and%20Use%20of%20Proceeds) The company reports no unregistered sales of equity securities during the reporting period - None[518](index=518&type=chunk) [Defaults Upon Senior Securities](index=165&type=section&id=Item%203.%20Defaults%20Upon%20Senior%20Securities) The company reports no defaults upon senior securities - None[520](index=520&type=chunk) [Mine Safety Disclosures](index=165&type=section&id=Item%204.%20Mine%20Safety%20Disclosures) The company states that this item is not applicable - Not applicable[522](index=522&type=chunk) [Other Information](index=165&type=section&id=Item%205.%20Other%20Information) The company reports no other information required for disclosure under this item - None[523](index=523&type=chunk) [Exhibits](index=166&type=section&id=Item%206.%20Exhibits) This section provides an index of exhibits filed with the Form 10-Q, including executive agreements and certifications - The report includes an index of exhibits filed, such as executive certifications and amendments to key agreements[525](index=525&type=chunk)[526](index=526&type=chunk)

Financial Data and Key Metrics Changes - The company ended Q1 2022 with approximately $267.1 million in cash, cash equivalents, and marketable securities, down from $315.8 million as of December 31, 2021 [42] - R&D expenses for Q1 2022 were $26.2 million, compared to $25 million for the same quarter in 2021, primarily due to increases in clinical manufacturing and development expenses [43] - G&A expenses rose to $15.1 million in Q1 2022 from $12.5 million in the same quarter of 2021, driven by increased personnel-related expenses [45] - The net loss for Q1 2022 was $42.8 million, compared to $38.9 million for the same quarter in 2021 [46] Business Line Data and Key Metrics Changes - The company is focusing on three ongoing clinical programs: GM1 gangliosidosis, Krabbe disease, and frontotemporal dementia (FTD) [12][34] - The Imagine-1 trial for GM1 gangliosidosis reported positive interim safety and clinical efficacy data, with dosing of patients in multiple cohorts [9][21] - The GALax-C trial for Krabbe disease has opened additional clinical sites and reported a Grade-4 adverse event in the first patient, but the trial will continue with modifications [27][31] Market Data and Key Metrics Changes - The company has established a global network of trial sites across the U.S., Brazil, Canada, UK, Israel, and The Netherlands for its clinical programs [10] - The strategic decision to focus on specific programs has resulted in returning rights for certain programs to the University of Pennsylvania [13] Company Strategy and Development Direction - The company is committed to developing transformative therapies for CNS disorders with limited treatment options and has streamlined its operations to extend its cash runway into Q2 2024 [15] - The strategic prioritization includes a focus on ongoing clinical programs and a reduction in operating expenses through workforce reduction and slowed investment in manufacturing [11][14] Management's Comments on Operating Environment and Future Outlook - Management expressed confidence in the progress made in Q1 2022 and anticipates reporting initial data from ongoing clinical trials in the second half of 2022 [48] - The company is optimistic about delivering multiple value-creating clinical milestones over the next two years [15] Other Important Information - The company has retained eight additional license options for future CNS indications through its partnership with Penn's Gene Therapy Program [13] - The company is actively working to improve patient recruitment for its clinical trials, particularly in the FTD program [36][84] Q&A Session Summary Question: Clarification on the Krabbe hydrocephalus event - Management noted that imaging prior to dosing showed changes in the ventricles, suggesting a potential link to disease progression rather than the drug itself [52][53] Question: Key outcomes measures for GM1 presentation - Management highlighted that the upcoming presentation will include updated data on biomarkers and clinical outcomes from the Imagine-1 trial [59] Question: Recruitment dynamics for GM1 program - Management indicated that they are open to collaborating with other centers to accelerate patient recruitment following the discontinuation of a competitor program [61] Question: Update on Krabbe disease trial - Management confirmed that the IDMC has approved proceeding with dosing and that they are revising the clinical trial protocol based on recommendations [68][70] Question: Changes to inclusion criteria for PBFT02 - Management confirmed that inclusion criteria were updated to broaden eligibility and improve enrollment [82] Question: Screening for GRN mutations in FTD - Management acknowledged challenges in identifying patients with GRN mutations and emphasized efforts to improve genetic testing and patient identification [110][113]

Pipeline and Programs - Passage Bio is developing transformative therapies for CNS disorders, targeting both rare and large patient populations[5] - The company's pipeline includes programs for GM1 gangliosidosis (PBGM01), Krabbe disease (PBKR03), frontotemporal dementia (PBFT02), amyotrophic lateral sclerosis (PBAL05), Huntington's disease, Alzheimer's disease, and temporal lobe epilepsy[5] - PBGM01 is in Phase 1/2 clinical trials for GM1 gangliosidosis, a rare pediatric disease with an incidence of approximately 1 per 100,000 live births worldwide[5, 11] - PBKR03 is in Phase 1/2 clinical trials for Krabbe disease, another rare pediatric disease with an incidence of approximately 26 per million live births worldwide[5, 39] - PBFT02 is in Phase 1/2 clinical trials for frontotemporal dementia (FTD-GRN), a rare adult disease with an estimated U S prevalence of approximately 3,000 to 6,000 patients[5, 46] Clinical Data and Milestones - Interim data from the PBGM01 Phase 1/2 trial showed a positive safety profile, demonstration of functional transgene expression, and meaningful gains in developmental milestones in Cohort 1[15, 18] - In PBGM01 Cohort 1, post-treatment CSF and serum β-gal activity for both patients were above natural history study patient values[18] - Patient 1 in the PBGM01 trial demonstrated meaningful gains in developmental milestones, advancing from baseline to 9 months developmental age[31] - Patient 2 in the PBGM01 trial regained previously lost developmental milestones at month 4, including the ability to walk and use specific words[36] - The company anticipates initial safety and biomarker data from PBKR03's GALax-C trial by the end of 2022[44] Financials - Passage Bio had a cash balance of $267 million as of March 31, 2022, which is expected to fund operations into Q2 2024[62]

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________ to ________ Commission File Number: 001-39231 PASSAGE BIO, INC. (Exact Name of Registrant as Specified in its Charter) Delaware 82- ...

Company Overview - Passage Bio is dedicated to developing genetic medicines for central nervous system (CNS) disorders[3, 70] - The company leverages a partnership with Penn's Gene Therapy Program (GTP) for AAV gene therapy research[3, 4, 70] - Passage Bio has dedicated manufacturing and analytics capabilities to ensure product supply[3, 8, 70] Pipeline and Portfolio - The company has a diversified portfolio strategy across rare and large, monogenic and non-monogenic CNS indications[5, 6, 70] - The pipeline includes 3 clinical-stage therapies and 6 research-stage pipeline candidates[5] - The company is advancing programs for Amyotrophic Lateral Sclerosis (ALS), Charcot-Marie-Tooth Type 2A (CMT2A), Parkinson's, Canavan and Huntington's diseases[68] Clinical Programs - **PBGM01 (GM1 Gangliosidosis):** Ongoing Phase 1/2 Imagine-1 trial showed a positive safety profile, functional transgene expression, and developmental gains in Cohort 1[5, 15, 18] - Interim Cohort 1 data showed increases in CSF β-gal activity of +0.6 nmol/mL/3hr and serum β-gal activity of +6.0 nmol/mL/3hr in Patient 1[21, 23] - Patient 1 demonstrated meaningful gains in developmental milestones, advancing to 9 months developmental age[29] - Patient 2 regained previously lost developmental milestones at month 4[36] - **PBKR03 (Krabbe Disease):** Phase 1/2 GALax-C trial is focused on early infantile Krabbe, with first patient dosing expected in early 2022[5, 43, 44] - The trial includes dose escalation and confirmatory cohorts with doses of 1.5e11 GC/g and 5.0e11 GC/g[44] - **PBFT02 (Frontotemporal Dementia - GRN):** Phase 1/2 upliFT-D trial is focused on early symptomatic FTD-GRN, with first patient dosing expected in early 2022[5, 48, 49] - The trial includes dose escalation cohorts with doses of 3.3e10 GC/g and 1.1e11 GC/g[49] Financials - The company had a cash balance of $316 million as of December 31, 2021[69] - The cash on hand is expected to fund operations to year-end 2023[69]