FDA Lifts Hold on Rocket Pharmaceuticals’ Pivotal Gene Therapy Study at Lower Dose

The FDA has lifted its clinical hold on Rocket Pharmaceuticals' pivotal Phase II gene therapy trial for Danon disease after previously suspending the study following a patient death in May 2025 due to capillary leak syndrome135.

The study will now proceed with a lower dose of the investigational gene therapy, RP-A501, aligning with the lower range of effective doses tested in an earlier Phase I trial35.

Rocket Pharmaceuticals has also changed its pre-treatment regimen, discontinuing the use of a C3 complement inhibitor that was suspected to contribute to the adverse event, and adopted an immunomodulatory approach similar to what was used in a pediatric cohort135.

Danon disease is a rare genetic disorder affecting the heart muscle caused by mutations in the LAMP2 gene, eventually leading to heart failure3.

The FDA hold was initially instituted to investigate the cause of the patient death and safety of the trial, with new protocol adjustments aimed at mitigating risk15.

Sources:

1. https://www.fiercebiotech.com/biotech/rocket-launches-fda-hold-uncertainty-about-biotechs-cash-runway-looms

3. https://www.biospace.com/fda/rocket-re-ignites-phase-ii-trial-after-fda-lifts-clinical-hold

5. https://www.biopharmadive.com/news/rocket-fda-lift-hold-danon-gene-therapy-trial/758117/