Landmark 303 · Trial in people
CAP-003 intravenous GBA1 gene therapy (Capsida)
Withdrawn before anyone was treated, after a child died in a trial of another drug with the same virus shell. It was not a test of the gene itself.
In short
Capsida's planned 31-person trial of an intravenous gene therapy for GBA1-linked Parkinson's was withdrawn with no patients dosed, after a child died in the company's trial of a drug using the same engineered virus shell.
- What it is
- Trial in people
- Outcome
- Did not work
- When
- 2025–2026
- Size
- Phase 2
- Approach
- Replace or repair what's lost
- Research lane
- Gene therapy & delivery
- Trial registry
- NCT07011771
- Last checked
- 19 Oct 2026
The research record
This is the project's file for this landmark, as written and checked. Sources are listed at the end; anything not yet confirmed is marked "Not yet verified".
Who
Capsida Biotherapeutics. Planned US sites included Rush University, Columbia University and the University of Pennsylvania. Registered as NCT07011771.
What happened
CAP-003 was meant to deliver a working GBA1 gene (the enzyme GCase is low in GBA1 carriers) with a single intravenous infusion. Capsida used an engineered AAV capsid (the virus's protein shell) designed to cross the blood-brain barrier, the filter between blood and brain (landmark 111). The company said monkey studies showed dose-dependent rises in GCase in the substantia nigra, cortex, caudate and putamen, with less liver uptake than AAV9. Capsida announced the FDA's clearance of the IND (permission to test in people) on 11 June 2025.
The registry planned about 31 people aged 21 to 75 (6 in dose escalation, about 25 in Phase 2), a 2-year follow-up and a 3-year safety extension. It lists a start of 18 Aug 2025 but 0 participants, status Withdrawn.
On 10 Sept 2025 Capsida disclosed that the first child treated in its CAP-002 trial for STXBP1 disorders had died; the trial was paused. In January 2026 the company gave the cause as cerebral edema (brain swelling), and an autopsy did not find the underlying cause. On 11 May 2026 it announced closure of that trial and of CAP-003, which used the same capsid; no CAP-003 patient was dosed. The registry records the reason as a protocol stopping rule met in a separate trial. Capsida says it is studying how the capsid interacts with a protein called ADAM15, and moving to a capsid that uses a different receptor, RECK.
Why it moved us toward a cure
It is the first attempt to give a Parkinson's gene therapy by vein rather than by brain surgery or spinal-fluid injection, a route that avoids the injection into spinal fluid used for PR001 (landmark 109). Its closure is a safety warning for engineered capsids, not a test of GBA1 gene replacement.
Outcome
Dead end for this product. The idea of replacing GBA1 is still tested by other programmes (landmark 302). The cause of the death is unknown, so it is not known whether the capsid or the gene cargo was responsible.
Sources
- ClinicalTrials.gov NCT07011771 (API checked 19 Oct 2026)
- Pharmaceutical Technology on the IND, 12 June 2025; PackGene repost of Capsida's 11 June 2025 release
- BioPharma Dive, 11 Sept 2025
- Bioxconomy on the closure, May 2026
- Not yet verified: Capsida's own May 2026 notice (blocked); the RECK plan and "no patients dosed" rest on search summaries; whether CAP-003 used the same capsid is from company text relayed by secondary sites.
How it connects
Built on
- builds on AAV capsids that cross into the brain · 2016
- builds on GBA gene therapy (PR001) · 2020
Led to
None recorded.