Capsida Receives FDA Fast Track Designation for Its Potential First-in-Class IV-Administered Gene Therapy for STXBP1 Developmental and Epileptic Encephalopathy

Business Wire

29-05-2025

THOUSAND OAKS, Calif.--(BUSINESS WIRE)--Capsida Biotherapeutics ('Capsida') today announced the U.S. Food and Drug Administration (FDA) has granted Fast Track designation to its CAP-002 program. CAP-002 is the company's investigational IV-administered gene therapy for the treatment of STXBP1 developmental and epileptic encephalopathy (STXBP1-DEE), and is the first IV-delivered, AAV blood brain barrier-crossing genetic medicine program entering a human clinical trial.
The FDA's Fast Track designation is designed to facilitate the development and expedite the review of drugs that are intended to treat serious or life-threatening conditions and have the potential to address an unmet medical need. A drug that receives Fast Track designation may be eligible for more frequent meetings and communications with the FDA and rolling review of application for marketing approval. A Fast Track-designated drug also may be eligible for Priority Review if relevant criteria are met.
'FDA's granting of Fast Track designation for CAP-002 highlights the significant unmet need in the treatment of STXBP1-DEE and the potential of CAP-002 to be a first-in-class treatment,' said Swati Tole, M.D., Chief Medical Officer of Capsida Biotherapeutics. 'We are currently initiating study start-up activities for our Phase 1/2a SYNRGY clinical trial with the aim of providing the first potential disease-modifying treatment for STXBP1-DEE patients and their families.'
About CAP-002 and the SYNRGY Clinical Trial
CAP-002 is enabled by one of Capsida's proprietary engineered capsids and optimized cargo. In non-human primate (NHP) studies to date, CAP-002 has established transduction of more than 70% of neurons across critical brain areas, while simultaneously detargeting the liver and dorsal root ganglia. This brain-wide expression of STXBP1 has the potential to correct seizures, developmental disabilities, and motor abnormalities, after a single IV infusion. The NHP Good Laboratory Practice (GLP) toxicology study demonstrated a well-tolerated safety profile with no adverse histopathology. CAP-002 is manufactured in Capsida's state-of-the-art wholly owned facility using a proprietary manufacturing process. CAP-002 received FDA Orphan Drug Designation in October 2024 and Investigational New Drug (IND) clearance in May 2025. Capsida expects to dose the first patient in the SYNRGY Phase 1/2a clinical trial in the third quarter of this year. For more information about the SYNRGY clinical trial, please visit www.clinicaltrials.gov (NCT06983158).
About STXBP1-DEE
Syntaxin-binding protein 1 developmental and epileptic encephalopathy (STXBP1-DEE) is estimated to affect up to one in 26,000 births globally, equating to approximately 5,000 pediatric patients in the U.S. and Europe. The STXBP1 protein is present in every neuron and is essential for normal neurotransmission. Mutations in the STXBP1 gene are associated with early-onset seizures, severe developmental delay and intellectual disability, motor abnormalities, and a risk of sudden unexpected death in epilepsy (SUDEP). There are no approved treatments for STXBP1-DEE.
About Capsida Biotherapeutics
Capsida Biotherapeutics is a clinical-stage, fully integrated next-generation genetic medicines company. It has 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 its first-in-class investigational treatment for STXBP1 developmental and epileptic encephalopathy (STXBP1-DEE), which has received U.S. Food and Drug Administration Investigational New Drug (IND) clearance to initiate the SYNRGY Ph1/2a clinical trial. Capsida's pipeline also includes potential best-in-class treatments for Parkinson's disease associated with GBA mutations (PD-GBA) and Friedreich's ataxia (FA). The PD-GBA program is also on track to enter clinical development in the second quarter of 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.