Capsida to Present Progress Updates at the ASGCT Annual Meeting, Including NHP GLP Toxicology Study Results for its Potential First-in-Class STXBP1 Developmental and Epileptic Encephalopathy Program (CAP-002 STXBP1-DEE)

Capsida will also present data from its potential best-in-class programs for Parkinson’s disease associated with GBA mutations (CAP-003 PD-GBA) and Friedreich’s ataxia (CAP-004), as well as capsid engineering and manufacturing

Both CAP-002 STXBP1-DEE and CAP-003 PD-GBA are on track to enter clinical development this quarter

THOUSAND OAKS, Calif., April 28, 2025 — Capsida Biotherapeutics (“Capsida”) today announced it will present new data on its positive progress across its wholly owned pipeline, proprietary capsid engineering, and manufacturing in seven scientific presentations accepted at the 28th Annual Meeting of the American Society of Gene & Cell Therapy (ASGCT), taking place May 13-17, 2025, in New Orleans and virtually.

Capsida will deliver three oral presentations highlighting advances in Capsida’s pipeline of intravenously (IV)-delivered genetic medicines enabled by its proprietary engineered capsids and cargo. The Company will deliver an oral presentation on non-human primate (NHP) GLP toxicology results of CAP-002 for STXBP1-DEE demonstrating widespread and safe STXBP1 expression throughout the brain that exceeds thresholds needed to correct seizures, motor abnormalities, and developmental disabilities. A second oral presentation will feature preclinical data on CAP-004 for Friedreich’s ataxia (FA), Capsida’s single IV-delivered gene therapy indicating high rates of expression across central nervous system (CNS), cardiac, and sensory tissues, establishing potential to treat all manifestations of the disease. A third oral presentation will showcase Capsida’s identification of novel blood-brain barrier receptors and highly CNS tropic and peripherally detargeted capsids.

“These data reflect the significant progress we are making in translating Capsida’s innovative capabilities into differentiated clinical therapies,” said Peter Anastasiou, Capsida’s Chief Executive Officer. “We are on track to enter the clinic with our STXBP1-DEE and PD-GBA programs this quarter, with the potential to bring disease-modifying and possibly curative treatments to these communities who so desperately need them.”

The presentations are listed below.

Abstracts can be found at https://annualmeeting.asgct.org. Data from presentations are embargoed until 6:00 AM CT on the presentation day for oral abstracts and until 6:00 AM CT on May 13, 2025 for poster abstracts.

Oral Presentations:

Pipeline
Systemic AAV Gene Therapy with Next Generation Engineered Capsid Demonstrates Expression Levels Supporting Potential Therapeutic Benefit for CNS, Cardiac, and Sensory Symptoms in Friedreich’s Ataxia
Date and Time: Wednesday, May 14, 2025, 1:45-2:00 PM CT
Session: Neurologic Diseases – Vectorology and Gene Therapy
Abstract Number: 75
Location: New Orleans Theater A
Presenter: Celeste Stephany, Ph.D., Director of CNS and Ophthalmology Preclinical Research, Capsida

Systemic Gene Therapy CAP-002 Demonstrates Potential for Disease-Modifying Treatment of Seizures and Motor and Cognitive Deficits of STXBP1-DEE Using an Engineered, CNS-Targeted AAV
Date and Time: Wednesday, May 14, 2025, 3:45-4:00 PM CT
Session: Viral Vectors in Large Animal Models
Abstract Number: 123
Location: New Orleans Theater B
Presenter: Nick Flytzanis, Ph.D., Founder, Chief Research and Innovation Officer, Capsida

Engineering
Identification of Multiple Novel Blood-Brain-Barrier Receptors for CNS Gene Therapy and Other Drug Modalities via an Integrated AAV Capsid Engineering Platform
Date and Time: Wednesday, May 14, 2025, 2:45-3:00 PM CT
Session: AAV Gene Transfer (A): Crossing the Blood-Brain Barrier
Abstract Number: 93
Location: New Orleans Theater C
Presenter: Nick Goeden, Ph.D., Founder, Chief Technology Officer, Capsida

Poster Presentations:

Preclinical
CAP-003, a CNS-Targeted IV-delivered AAV Gene Therapy, Safely Increases Brain GCase in NHPs to Level Supporting Potential Normalization of Activity in PD-GBA Patients
Date and Time: Wednesday, May 14, 2025, 5:30-7:00 PM CT
Session: Wednesday Poster Reception
Abstract Number: 1435
Location: Hall I2
Presenter: Kim McDowell, Ph.D., Director, Preclinical Research, Capsida

Process Development, Analytical Development, Manufacturing
rAAV Manufacturing Solutions: Strategic Designs of Engineered rAAV Two Plasmid Systems for Cost Effective Scaling and Product Safety
Date and Time: Tuesday, May 13, 2025, 5:30-7:00 PM CT
Session: Tuesday Poster Reception
Abstract Number: 962
Location: Hall I2
Presenter: Jenna Rodden, Senior Research Associate, Capsida

Dual-Platform NGS for Comprehensive Characterization of Engineered rAAV Vector Integrity
Date and Time: Wednesday, May 14, 2025, 5:30-7:00 PM CT
Session: Wednesday Poster Reception
Abstract Number: 1326
Location: Hall I2
Presenter: Zach Mason, Associate Scientist, Capsida

Development of a Novel Automated Loading Approach Which Significantly Reduces Processing Time for Enriching Full AAV Capsids Using Ultracentrifugation
Date and Time: Thursday, May 15, 2025, 5:30-7:00 PM CT
Session: Thursday Poster Reception
Abstract Number: 1833
Location: Hall I2
Presenter: Varun Gejji, Ph.D., Senior Scientist, Capsida

About Capsida Biotherapeutics

Capsida Biotherapeutics is a fully integrated next-generation genetic medicines company with a central nervous system (CNS) pipeline consisting of disease-modifying and potentially curative treatments for rare and more common diseases across all ages. Capsida’s wholly owned pipeline includes a potential first-in-class treatment for STXBP1 developmental and epileptic encephalopathy (STXBP1-DEE), best-in-class treatment for Parkinson’s disease associated with GBA mutations (PD-GBA), and best-in-class therapy for Friedreich’s ataxia (FA). The STXBP1-DEE and PD-GBA programs are on track to enter the clinic in 1H 2025. In addition to its wholly owned programs, the Company has validating partnerships with AbbVie, Lilly, and CRISPR Therapeutics. Capsida was founded in 2019 by lead investors Versant Ventures and Westlake Village BioPartners and originated from groundbreaking research in the laboratory of Viviana Gradinaru, Ph.D., a neuroscience professor at Caltech. Visit us at www.capsida.com.

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