A Difficult Community Update – Capsida Clinical Trial

Dear STXBP1 Community, 

We are devastated to share that the first participant in the Capsida CAP-002 SYNRGY clinical trial died a few days after dosing. Our deepest love and condolences are with the family, and we ask everyone to honor their privacy during this profoundly difficult time.

We know that waiting for answers is incredibly hard and that everyone wants to find out what happened. While we do not have these answers yet, we are in close contact with the study sponsor and investigators and will share verified updates as the formal safety review progresses.

The STXBP1 Foundation was created by parents, guided by love and determination, and we stand together in loss. With care and safety as priorities, we remain committed to everyone affected by STXBP1.

With care, 

The STXBP1 Board of Directors 

Below is a letter to the STXBP1 Community from Capsida.