> ## Content Index
> Fetch the complete content index at: https://www.fdaweb.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# Capsida Pauses Gene Therapy Trial After Death
- URL: https://www.fdaweb.com/capsida-pauses-gene-therapy-trial-after-death/
- Published: 2025-09-11T12:00:00.000Z
- Updated: 2026-09-14T15:21:29.000Z
- Author: David McFarland
- Tags: FDA Policy/General, #legacy-id-D5159854

Capsida Biotherapeutics has halted enrollment in its SYNRGY clinical trial that is evaluating CAP-002, an investigational intravenous (IV)-administered gene therapy for treating STXBP1 developmental and epileptic encephalopathy, due to a patient death in the trial. The company says CAP-002 is the first IV-delivered, adeno-associated virus blood brain barrier-crossing genetic medicine entering a human clinical trial.

The company disclosed the development in a letter to the STXBP1 community. “We have voluntarily paused the CAP-002 SYNRGY study while we determine the root cause of the patient’s passing,” it said. The company confirmed it has notified FDA and will submit a full report in compliance with regulatory requirements.

The trial, part of Capsida’s gene therapy program for STXBP1-Related Disorders, is designed to address severe neurological symptoms associated with mutations in the STXBP1 gene. These disorders often present in infancy with developmental delay, seizures, and motor impairment.