# EDGAR Filing Document

**Accession Number:** 0001787297
**File Stem:** 0001558370-23-001964
**Filing Date:** 2023-2
**Character Count:** 33546
**Document Hash:** ccb0734e9542817f78d3f14bb7c2d86b
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001558370-23-001964.hdr.sgml**: 20230224

**ACCESSION NUMBER**: 0001558370-23-001964

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 28

**CONFORMED PERIOD OF REPORT**: 20230224

**ITEM INFORMATION**: Regulation FD Disclosure

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20230224

**DATE AS OF CHANGE**: 20230224

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Passage BIO, Inc.
- **CENTRAL INDEX KEY:** 0001787297
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **IRS NUMBER:** 822729751
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39231
- **FILM NUMBER:** 23662309

**BUSINESS ADDRESS:**
- **STREET 1:** ONE COMMERCE SQUARE
- **STREET 2:** 2005 MARKET STREET, 39TH FLOOR
- **CITY:** PHILADELPHIA
- **STATE:** PA
- **ZIP:** 19103
- **BUSINESS PHONE:** 2678660312

**MAIL ADDRESS:**
- **STREET 1:** ONE COMMERCE SQUARE
- **STREET 2:** 2005 MARKET STREET, 39TH FLOOR
- **CITY:** PHILADELPHIA
- **STATE:** PA
- **ZIP:** 19103

?xml version='1.0' encoding='UTF-8'?

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

**FORM 8-K**

**CURRENT REPORT**

**Pursuant to Section 13 or 15(d)**

**of the Securities Exchange Act of 1934**

**Date of Report (Date of earliest event reported): February 24, 2023**

## PASSAGE BIO, INC.
**(Exact name of registrant as specified in its charter)**

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| | | |
|:---|:---|:---|
| **Delaware** | **001-39231** | **82-2729751** |
| **(State or other jurisdiction**<br>**of incorporation)** | **(CommissionFile Number)** | **(IRS EmployerIdentification No.)** |

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| | |
|:---|:---|
| **One Commerce Square2005 Market Street, 39**<sup>th</sup> **Floor** <br>**Philadelphia, PA** | **19103** |
| **(Address of principal executive offices)** | **(Zip Code)** |

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**(267) 866-0311**

**(Registrant's telephone number, including area code)**

**N/A**

**(Former name or former address, if changed since last report)**

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

**Securities registered pursuant to Section 12(b) of the Act:**

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| | | |
|:---|:---|:---|
| **Title of each class** | **Trading symbol(s)** | **Name of each exchange on which registered** |
| Common Stock, $0.0001 Par Value Per Share | PASG | The Nasdaq Stock Market LLC<br>(Nasdaq Global Select Market) |

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Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

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**Item 7.01 Regulation FD Disclosure.**

On February 24, 2023, Passage Bio, Inc. (the "***Company***") will present a scientific presentation at the 19th Annual WORLD*Symposium* Conference (the "***WORLD Presentation***") providing additional interim data from the Company's Imagine-1 clinical trial, a Phase 1/2 study of PBGM01, a gene therapy for the treatment of GM1 gangliosidosis.

The Company also issued a press release on February 24, 2023, related to the WORLD Presentation.

A copy of the press release and WORLD Presentation are attached as Exhibits 99.1 and 99.2, respectively, to this Current Report on Form 8-K.

The information in this Item 7.01, including Exhibits 99.1 and 99.2 to this report, shall not be deemed to be "filed" for purposes of Section 18 of the Exchange Act, or otherwise subject to the liabilities of that section or Sections 11 and 12(a)(2) of the Securities Act. The information contained in this Item 7.01 and in the accompanying Exhibits 99.1 and 99.2 shall not be incorporated by reference into any other filing under the Exchange Act or under the Securities Act, except as shall be expressly set forth by specific reference in such filing.

**Item 9.01** **Financial Statements and Exhibits.**

(d) Exhibits

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| | |
|:---|:---|
| **Exhibit No.** | **Description** |
| 99.1 | [Passage Bio, Inc. press release dated February 24, 2023.](pasg-20230224xex99d1.htm) |
| 99.2 | [WORLD Presentation.](pasg-20230224xex99d2.htm) |
| 104 | Cover Page Interactive Data File (formatted as Inline XBRL). |

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**SIGNATURE**

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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| | | |
|:---|:---|:---|
|  | **PASSAGE BIO, INC.** | **PASSAGE BIO, INC.** |
| Date: February 24, 2023 | By: | /s/ Simona King |
|  |  | Simona King |
|  |  | Chief Financial Officer |

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## Exhibit 99.1

**Exhibit 99.1**

**Passage Bio Presents Additional Interim Data from Imagine-1 Study for GM1 Gangliosidosis at 19**<sup>th</sup> **Annual WORLDSymposium™ 2023**

*–* *Additional interim biomarker and efficacy data from first six patients continue to demonstrate both the high and low dose of PBGM01 led to a biological effect in patients*

*–* *PBGM01 administration resulted in stabilization of MRI severity scores in all treated patients through 6 to twelve months of follow-up* 

**PHILADELPHIA, February 24, 2023 —** Passage Bio, Inc. (Nasdaq: PASG), a clinical-stage genetic medicines company focused on developing transformative therapies for central nervous system (CNS) disorders, announced updated clinical data from Imagine-1, a Phase 1/2 study of PBGM01, a gene therapy for GM1 gangliosidosis (GM1), are being presented today at the 19th Annual WORLD*Symposium*™. Imagine-1 is a global, open-label, dose-escalation study of the AAVhu68 gene therapy PBGM01 delivered by intra-cisterna magna (ICM) injection in four cohorts of pediatric subjects with early and late infantile GM1 Gangliosidosis (GM1). GM1 is a rare, fatal lysosomal storage disease in which mutations in the *GLB1* gene result in very low activity of the enzyme beta-galactosidase (β-Gal). The presentations at the WORLD*Symposium*™ include safety, biomarker and efficacy data from six treated patients in the first three cohorts of the study.

"We are pleased to share promising data from the first six patients in our Imagine-1 study that continue to demonstrate PBGM01 has exerted a biological effect in patients with infantile forms of GM1 gangliosidosis," said William Chou, M.D., chief executive officer of Passage Bio. "At this interim analysis, all treated patients showed stabilization of MRI severity scores, a potential marker of disease severity and progression measured by structural damage of the brain. Furthermore, patients exhibited decreases in urine levels of the β-Gal substrate Dp5, an exploratory biomarker of peripheral β-Gal activity. These data are supported by the favorable safety profile of PBGM01 and bolster our confidence in PBGM01 as a potential treatment option for GM1 patients. We look forward to continued advancement of our Imagine-1 study and sharing new data from Cohort 4 by mid-year."

The data presented at the 19th Annual WORLD*Symposium*™ build upon the positive interim safety and biomarker data announced by the company in December 2022, which showed that PBGM01 administration was well tolerated and had a favorable safety profile, with no treatment-related serious adverse events, no complications related to ICM delivery and no evidence of dorsal root ganglion (DRG) toxicity. Moreover, PGBM01 administration resulted in dose dependent increases in CSF β-Gal activity, as well as dose-dependent decreases in CSF GM1 ganglioside levels.

**Updated interim results from cohorts 1-3 of the Imagine-1 study**

**Magnetic Resonance Imaging (MRI) Severity Score**

● The MRI severity score, a novel scoring metric, can be used to assess treatment effects on brain volume and white matter integrity for GM1 patients based on baseline and follow-up brain MRI scans. This score measures cerebral and cerebellar atrophy, abnormalities in white matter, and signal abnormalities in the basal ganglia and hippocampi to determine levels of structural damage.

● Natural history data from late infantile GM1 patients showed MRI severity scores increased in the majority of children over a follow-up period of six months to four years.

● Preliminary data over a follow-up period of six to 12 months showed PBGM01 administration was associated with stabilization of MRI severity scores in all treated patients.

**Biomarker Data**

● PBGM01 administration resulted in decreases in β-Gal substrate Dp5 levels in urine, suggesting ICM delivery of PBGM01 results in peripheral β-Gal activity.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;o Both patients who received the high dose (Cohort 2, late infantile) exhibited prominent decreases in urine Dp5 levels.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;o Patients with high baseline levels treated with the low dose of PBGM01 exhibited decreases in urine Dp5 levels.

A copy of the data presentation will be available on the Investor Events and Presentations page of the Passage Bio corporate website following presentation of the materials.

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#### About Imagine-1
Imagine-1 is a Phase 1/2, global, open-label, dose-escalation study of PBGM01 administered by a single injection into the cisterna magna in pediatric subjects with early and late infantile GM1. The clinical program has treated a total of four cohorts of two patients each, with separate dose-escalation cohorts for late infantile GM1 and early infantile GM1. The primary goal of the study is to first assess safety and tolerability and then efficacy of PBGM01 in patients. The U.S. Food and Drug Administration has granted PBGM01 Fast Track, Orphan Drug, and Rare Pediatric Disease designations. PBGM01 has also received an Orphan designation and Advanced Therapy Medicinal Product from the European Commission.

To learn more about the clinical trial program, please visit ClinicalTrials.gov: NCT04713475.

#### About PBGM01
PBGM01 is an AAV-delivery gene therapy currently being developed for the treatment of infantile GM1, in which patients have mutations in the *GLB1* gene causing little or no residual β-Gal enzyme activity and subsequent neurodegeneration. PBGM01 utilizes a next-generation AAVhu68 capsid administered through the cisterna magna to deliver a functional *GLB1* gene encoding β-Gal to the brain and peripheral tissues. By increasing β-Gal activity, PBGM01 has the potential to reduce accumulation of toxic GM1 gangliosides and reverse neuronal toxicity, thereby restoring developmental potential. In preclinical models, PBGM01 has demonstrated broad brain distribution and high levels of expression of the β-Gal enzyme in both the CNS and critical peripheral organs, suggesting potential treatment for both the CNS and peripheral manifestations of GM1.

#### About GM1
GM1, a rare monogenic lysosomal storage disease, is caused by mutations in the GLB1 gene, which encodes the lysosomal enzyme β-gal. Reduced β-gal activity results in the accumulation of toxic levels of GM1 gangliosides in neurons throughout the brain, causing rapidly progressive neurodegeneration. GM1 accumulation also results in progressive damage to other tissues including the heart, liver, and bones and manifests with hypotonia (reduced muscle tone), progressive CNS dysfunction, seizures, and rapid developmental regression. Life expectancy for infants with GM1 ranges from 2-10 years, and infantile GM1 represents approximately 62.5 percent of the global GM1 incidence of 1 in 100,000 live births.

#### About Passage Bio
Passage Bio (Nasdaq: PASG) is a clinical-stage genetic medicines company on a mission to provide life-transforming therapies for patients with CNS diseases with limited or no approved treatment options. Our portfolio spans pediatric and adult CNS indications, and we are currently advancing clinical programs in GM1 gangliosidosis and frontotemporal dementia and our preclinical pipeline, including programs in amyotrophic lateral sclerosis and Huntington's disease. Based in Philadelphia, PA, our company has established a strategic collaboration and licensing agreement with the renowned University of Pennsylvania's Gene Therapy Program to conduct our discovery and IND-enabling preclinical work. Through this collaboration, we have enhanced access to a broad portfolio of gene therapy candidates and future gene therapy innovations that we then pair with our deep clinical, regulatory, manufacturing and commercial expertise to rapidly advance our robust pipeline of optimized gene therapies. As we work with speed and tenacity, we are always mindful of patients who may be able to benefit from our therapies. More information is available at www.passagebio.com.

#### Forward-Looking Statements
This press release contains "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 expectations about timing and execution of anticipated milestones, including progress of the Imagine-1 clinical trial and the availability of clinical data from the trial; our expectations about our collaborators' and partners' ability to execute key initiatives; our expectations about manufacturing plans and strategies; our expectations about cash runway; and the ability of our lead product candidates to treat their respective target monogenic CNS disorders. These forward-looking statements may be accompanied by such words as "aim," "anticipate," "believe," "could," "estimate," "expect," "forecast," "goal," "intend," "may," "might," "plan," "potential," "possible," "will," "would," and other words and terms of similar meaning. These statements involve risks and uncertainties that could cause actual results to differ materially from those reflected in such statements, including: our ability to develop and obtain regulatory approval for our product candidates; the timing and results of preclinical studies and clinical trials; risks associated with clinical trials, including our ability to adequately manage clinical activities, unexpected concerns that may arise from additional data or analysis obtained during clinical trials, regulatory authorities may require additional information or further studies, or may fail to approve or may delay approval of our drug candidates; the occurrence of adverse safety events; the risk that positive results in a preclinical study or clinical trial may not be replicated in subsequent trials or success in early stage clinical trials may not be

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predictive of results in later stage clinical trials; failure to protect and enforce our intellectual property, and other proprietary rights; our dependence on collaborators and other third parties for the development and manufacture of product candidates and other aspects of our business, which are outside of our full control; risks associated with current and potential delays, work stoppages, or supply chain disruptions caused by the coronavirus pandemic; and the other risks and uncertainties that are described in the Risk Factors section in documents the company files from time to time with the Securities and Exchange Commission (SEC), and other reports as filed with the SEC. Passage Bio undertakes no obligation to publicly update any forward-looking statement, whether written or oral, that may be made from time to time, whether as a result of new information, future developments or otherwise.

**For further information, please contact:** 

**Investors:** 

Stuart Henderson

Passage Bio

267.866.0114 <u>shenderson@passagebio.com</u> 

**Media:**

Mike Beyer<br>Sam Brown Inc. Healthcare Communications<br>312.961.2502<br>MikeBeyer@sambrown.com

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## Exhibit 99.2

#### Exhibit 99.2

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|:---|:---|
| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g001.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Imagine-1 Study: Updated interim safety, biomarker, and efficacy data from the Phase 1/2 open-label, multicenter study of a single dose, intracisterna magna administration of PBGM01 in type I (early onset) and type IIA (late onset) infantile GM1 gangliosidosis Jeanine Jarnes, PharmD, BCOP, BCPS Advanced Therapies Program, University of Minnesota |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g002.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2 GM1 Gangliosidosis is a Continuum Disease Severity Residual Enzyme Activity1,3-5,8 Negligible ~1-5% ~3-10% Type I (Early Infantile)1 • Onset <6 months1-5 • Survival: <3 years1 • No new developmental milestones reached after 3-6 months5,6 Type IIa (Late-Infantile)3 • Onset 6-24 months3,4 • Survival: 5 to 10 years2,5 • No new developmental milestones reached after 12-15 months6 Type IIb (Juvenile)3 • Onset 2-3 years3,4 • Survival into 2nd decade5 Imagine-1 Trial will include Type I (Early Infantile) and Type IIa (Late Infantile) patients7 GM1 Gangliosidosis is Characterized by Progressive Neurological Deterioration 1. Brunetti-Pierri N, Scaglia F. Mol Genet Metab. 2008;94(4):391-396. 2. Jarnes JR, et al. Mol Genet Metab. 2017;121(2):170-179. 3. Lang FM, et al. Mol Genet Metab. 2020;129(3):228-235. 4. Regier DS, et al. Am J Med Genet Part A. 2016;170(3):634-644. 5. King KE, et al. Mol Genet Meta Rep. 2020;25:100676. 6. Nicoli E-R, et al. Front Genet. 2021;12:734878. 7. Study of safety, tolerability and efficacy of PBGM01 in pediatric subjects with GM1 gangliosidosis (Imagine-1). ClinicalTrials.gov website. https://www.clinicaltrials.gov/ct2/show/NCT04713475. January 19, 2021. Updated March 7, 2022. Accessed January 19, 2023. 8. Regier DS, et al. GLB1-related disorders. In: Adam MP, et al., eds. GeneReviews® [Internet]. University of Washington, Seattle; 2019:1993-2022. https://www.ncbi.nlm.nih.gov/books/NBK164500/ October 17, 2013. Updated April 22, 2021. |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g003.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3 Imagine-1: Global Phase 1/2 Trial with PBGM01 \*Genome copies per gram of estimated brain weight. AAV, adeno-associated virus; CSF, cerebrospinal fluid; GLB1, galactosidase beta 1; IDMC, independent data monitoring committee. Vector is technology of The University of Pennsylvania (Gene Therapy Program). Study of safety, tolerability and efficacy of PBGM01 in pediatric subjects with GM1 gangliosidosis (Imagine-1). ClinicalTrials.gov website. January 19, 2021. Updated March 14, 2022. https://www.clinicaltrials.gov/ct2/show/NCT04713475. Accessed Jan 19, 2023. Trial Design Phase 1/2, multicenter, open-label, dose escalation and confirmatory study Route of Administration Intracisterna magna (ICM) Gene Therapy and Vector PBGM01 an investigational gene therapy composed of a codon-optimized, fully functional human GLB1 gene packaged in an AAV serotype hu68 capsid Duration Two years, with rollover into long-term follow-up study Primary Endpoints • Safety and tolerability • Efficacy (confirmatory cohort) Biomarkers • β-gal activity (CSF & serum) • GM1 gangliosides (CSF) • Other exploratory biomarkers Completed dosing of all patients in dose-ascending portion of study COHORT 4 Early Infantile DOSE 2 (1.1e11 GC/g)\* DOSE 1 (3.3e10 GC/g)\* Expansion Cohort Early Infantile Expansion Cohort Late Infantile COHORT 2 Late Infantile COHORT 3 Early Infantile COHORT 1 Late Infantile 60 days between subject enrollment in Cohorts 1-4 IDMC review Dosing complete |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g004.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4 Key Eligibility Criteria Early onset infantile (Type 1) • Aged ≥4 to <24 months, with onset of symptoms <6 months of age • Specific developmental milestones retained Late onset infantile (Type 2a) • Aged ≥6 to <36 months (with the exception of the low-dose Late Onset Infantile Cohort, which will be >12 to <36 months of age), with onset of symptoms ≥6 months • Specific developmental milestones retained Inclusion Criteria • Genetic and biochemical confirmation of GM1 gangliosidosis • Homozygous or compound heterozygous for GLB1 gene deletion or pathological mutation • β-gal activity below the lower bound of the normal range Study of safety, tolerability and efficacy of PBGM01 in pediatric subjects with GM1 gangliosidosis (Imagine-1). ClinicalTrials.gov website. January 19, 2021. Updated March 14, 2022. https://www.clinicaltrials.gov/ct2/show/NCT04713475. Accessed Jan 19, 2023.  |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g005.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5 Imagine-1 Baseline Patient Characteristics\* DBS, dry blood spot. 1Lower limit of normal: <5.0 nmol/mL/h. †Positive family history. \*Data cutoff of Nov 30, 2022. Patient 1 Patient 2 Patient 3 Patient 4 Patient 5 Patient 6 Diagnosis Late onset Late onset Early onset Late onset Early onset Late onset Dose level received Low dose Low dose Low dose High dose Low dose High dose Cohort 1 1 3 2 3 2 Gender Male Male Female Female Male Male Onset of symptoms (months) 14 12 5 11 birth 12 Chronological age at diagnosis (months) 2† 30 6 13 2 15 Chronological age at baseline (months) 14 31 15 18 6 17 DBS β-gal activity (nmol/mL/hr)1 0.0 0.2 0.0 0.0 0.1 0.0 Genotype c.601C>T, c.601C>T c.601C>T, c.1733AA>G c.694dupC, c.694dupC c.1370G>A, c.168C>G c.1577dup, c.1577dup c.1733A>G, c.802G>C |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g006.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6 PBGM01 was Well-Tolerated and Had a Favorable Safety Profile at Interim Analysis\* Adverse Events Total (N=6 participants) Any adverse event 90 Any serious adverse event (unrelated to PBGM01) 5 Any treatment-emergent adverse events 80 Treatment-emergent adverse events in ≥2 participants Abdominal distension 2 Blood cholesterol increased 3 Blood lactate dehydrogenase increased 2 Constipation 2 Cough 2 Hypertriglyceridemia 2 Urinary tract infection 2 No treatment-related serious adverse events All treatment-related adverse events were mild-to-moderate in severity No clinically significant changes in liver function requiring intervention No evidence of DRG toxicity, as measured by nerve conduction studies No complications related to ICM administration Favorable immunological profile with no antibodies against the transgene product detected in the CSF or serum CSF, cerebrospinal fluid; DRG, dorsal root ganglion; ICM, intracisternal magna. \*Patient follow-up ranged from 3 to 20 months post-dosing as of a data cutoff of Nov 30, 2022. |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g007.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7 Patients Manifest a Wide Range of Developmental Delay at Baseline Mild-moderate delay Developmental Delay at Baseline Marked delay Patient 1 Patient 2 Patient 3 Patient 4 Patient 5 Patient 6 Diagnosis Late onset Late onset Early onset Late onset Early onset Late onset Dosing cohort Low dose Low dose Low dose High dose Low dose High dose Chronological age at baseline (months) 14 31 15 18 6 17 Developmental age at baseline (Bayley; months) 12 7 0.5 2.5 0.5 5 Developmental delay at baseline (Bayley; months) 2 24 14.5 15.5 5.5 12 |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g008.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8 Preliminary Trend: Milder Developmental Delay at Dosing Associated with Improved Treatment Response \*The Vineland-II is caretaker-assessed.\*\*The Bayley-III is based on direct observation by a neurodevelopmental specialist. Data from Cohorts 1-3; data cut-off December 2022. 0 5 10 15 20 25 Overall Developmental Age (months) 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Chronological Age (months) Vineland-II\* P1 Late Infantile P2 Late Infantile P3 Early Infantile P5 Early Infantile P4 Late Infantile P6 Late Infantile Mild-to-moderate developmental delay Marked developmental delay 0 5 10 15 20 25 Overall Developmental Age (months) 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Chronological Age (months) Bayley-III\*\* P1 Late Infantile P2 Late Infantile P3 Early Infantile P5 Early Infantile P4 Late Infantile P6 Late Infantile Mild-to-moderate developmental delay Marked developmental delay Late Infantile: Circle Early Infantile: Square Low Dose: Solid Line High Dose: Dashed Line |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g009.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9 PBGM01 Associated with Stabilization of MRI Severity Score\* 0 3 6 9 12 15 18 21 0 3 6 9 12 Patient 1 Patient 2 Patient 3 Patient 4 Patient 5 Patient 6 Time from Treatment (Months) MRI Severity Score Late Infantile: Circle Early Infantile: Square Low Dose: Solid Line High Dose: Dashed Line Natural History of MRI Progression in Late Infantile Patients\*\* MRI Progression in Imagine-1 Study Patients Time Since Onset of Symptoms (Months) • MRI Severity Score: higher scores indicate more structural damage • Each Late Infantile patient is plotted independently to show change over time since symptom onset • Late Infantile patient scores increased in the majority of children over the follow-up period (6 months – 4 years) implying progression of structural damage \* MRI severity score based on cerebral and cerebellar atrophy, abnormalities in white matter, and signal abnormalities in basal ganglia and hippocampi \*\* Regier DS, et al. Am J Med Genet Part A. 2016;170(3):634-644. Figure adapted to show only late infantile GM1 patients. MRI, magnetic resonance imaging. MRI Severity Score Late Infantile Patients Data from Cohorts 1-3; data cut-off December 2022. 21 18 15 12 9 6 3 0 0 50 |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g010.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10 PBGM01 ICM Delivery Resulted in Dose Dependent Increases in Transgene Activity in CSF CSF, cerebrospinal fluid; ICM, intracisterna magna. \*Based on preliminary data from University of Pennsylvania's ODC Natural History Study (NHS) (NCT04041102); value range (0.3-1.81 nmol/mL/3hr). Data from Cohorts 1-3; data cutoff December 2022. 0 β-Gal, nmol/mL/3hr 6 5 4 3 2 1 0 0 60 120 180 240 300 360 NHS patient value range 3.6x baseline β-gal, CSF 4.7-5.2 baseline β-Gal, nmol/mL/3hr 6 5 4 3 2 1 0 60 120 180 240 300 360 1.2-2.8x baseline β-gal, CSF Late Infantile: Circle Early Infantile: Square P4 Late Infantile P6 Late Infantile Time (days) P1 Late Infantile P2 Late Infantile Time (days) P3 Early Infantile P5 Early Infantile NHS patient value range High dose Low dose Key Points • PBGM01 administration resulted in a dose-dependent increase in CSF -gal activity • High-dose PBGM01 resulted in 3.6-5.2 increase in CSF -gal activity relative to baseline • High-dose PBGM01 resulted in CSF -gal activity well above levels seen in Natural History Study (NHS)\* • Increased CSF -gal activity sustained for up to 12 months in Patient 1 • PGBM01 administration resulted in sustained -gal enzyme expression in blood |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g011.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11 PBGM01 ICM Delivery Resulted in Dose Dependent Decreases in CSF GM1 Gangliosides CSF, cerebrospinal fluid. \*Lang FM, et al. Mol Genet Metab.2020;129:228-235. Data from Cohorts 1-3; data cutoff December 2022. 0 High dose 600 400 200 0 0 47 375 75% drop from baseline GM1 Ganglioside, CSF Low dose Gangliosides, apparent nM 1,000 800 600 400 200 GM1 Ganglioside, CSF P4 Late Infantile P6 Late Infantile Time (days) P1 Late Infantile P2 Late Infantile Time (days) P3 Early Infantile P5 Early Infantile Gangliosides, apparent nM 94 141 188 234 281 328 0 47 94 141 188 234 281 328 375 Key Points • PBGM01 administration resulted in a dose-dependent decrease in CSF GM1 ganglioside levels • Decrease in CSF gangliosides correlate with higher levels of -gal activity • GM1 gangliosides hypothesized to mediate CNS manifestations of disease\* Late Infantile: Circle Early Infantile: Square |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g012.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12 PBGM01 ICM Delivery Resulted in Decreases in β-Gal Substrate Dp5 in Urine Key Points • Dp5 are O-linked pentasaccharides or (O-linked glycans) that accumulate in GM1; represent a biomarker of peripheral -gal activity\* • High dose PBGM01 administration resulted in prominent decreases in urine Dp5 levels • Low dose PBGM01 administration resulted in decreased Dp5 levels only in patients with high baseline levels • Suggests ICM delivery of PBGM01 results in increased peripheral -gal activity 0 100 200 300 400 0 50 100 150 200 250 300 350 400 450 500 550 Apparent pmoles/nmol creatinine Time (days) Dp5, Urine 0 200 400 600 800 1,000 1,200 0 50 100 150 200 250 300 350 400 450 500 550 Apparent pmoles/nmol creatinine Time (days) Dp5, Urine High dose Low dose P1 Late Infantile P2 Late Infantile P3 Early Infantile P5 Early Infantile P4 Late Infantile P6 Late Infantile Late Infantile: Circle Early Infantile: Square \*Lawrence R, et al, 2019; 21:100524. Data from Cohorts 1-3; data cutoff December 2022.  |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g013.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13 PBGM01: Summary and Future Directions AEs, adverse events; CSF, cerebrospinal fluid; DRG, dorsal root ganglion; ICM, intracisterna magna. Safety Favorable safety profile and well-tolerated • No serious AEs related to study treatment • No evidence of DRG toxicity • No evidence of antibody response to transgene • No complications related to ICM injection Biomarkers • High dose PBGM01 resulted in durable increases in CSF β-gal well above NHS • High dose PBGM01 resulted in durable decreases in β-gal substrate GM1 gangliosides in CSF • PBGM01 resulted in decreases in peripheral -gal substrate Dp5 in urine Clinical status • Milder developmental delay at the time of treatment is emerging as a determinant of treatment outcomes • PBGM01 treatment was associated with stabilization of MRI severity score • Pending results from high-dose cohorts, study eligibility criteria will consider incorporating degree of developmental delay |

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| &nbsp;&nbsp;![GRAPHIC](pasg-20230224xex99d2g014.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14 Thank You Acknowledgments • Thank you to the patients, families, and caregivers for their participation in this study • Thank you to the coordinators and site study staff who are instrumental in making this work happen • Vector discovered by the University of Pennsylvania's Gene Therapy Program • Imagine-1 is funded by Passage Bio • More information on the Imagine-1 trial (NCT04713475) can be found at www.clinicaltrials.gov Coauthors/Contributors • Debra L Day-Salvatore, Saint Peter's University Hospital • Can Ficicioglu, Children's Hospital of Philadelphia • Caroline A Hastings, UCSF Benioff Children's Hospital, Oakland • Geneviève Bernard, McGill University • Julien Baruteau, Great Ormond Street Hospital for Children • Fatih S Ezgu, Gazi University • Roberto Giugliani, Federal University of Rio Grande do Sul • Michal Inbar-Feigenberg, The Hospital for Sick Children • Chester B Whitley, University of Minnesota • Michael Gelb, University of Washington • Michelle Miller, University of Pennsylvania • Yan Ni, Victoria Ballard, Thomas Haws, Patricia Elsasser, Elizabeth Cunningham, Rose Johnstone, Pruthvia Nagilla, Samiah Al-Zaidy, Mark Forman, and David Weinstein, Passage Bio Poster 186 |

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