Rocket Pharmaceuticals, Inc. (NASDAQ: RCKT) announced on September 15, 2026, that it has reached an alignment with the U.S. Food and Drug Administration (FDA) regarding the continued enrollment and dosing of its global pivotal Phase 2 trial for RP-A501, a gene therapy candidate for Danon disease.
The FDA reviewed initial safety data from the first three patients treated under a modified protocol. The company reported that all three patients completed at least four weeks of follow-up and were discharged following protocol-specified observation. The FDA confirmed that no clinical or laboratory evidence of thrombotic microangiopathy or capillary leak syndrome was observed.
Based on this review, the FDA authorized continued enrollment and dosing at a recalibrated dose of 3.8 x 10^9 genome copies per kilogram (GC/kg) using commercial-grade product. The pivotal study population has been confirmed to include 12 male patients treated at this dose. Notably, the first three patients treated under the modified protocol will count toward this total, leaving nine additional patients to be enrolled.
Rocket expects to complete dosing of the remaining patients by mid-2027. The primary assessment of the trial will occur at 12 months using established co-primary endpoints: myocardial LAMP2 protein expression and a 10% reduction from baseline in left ventricular mass index. These endpoints are intended to support a potential accelerated approval pathway.
The modified protocol incorporates a recalibrated RP-A501 dose and an optimized immunomodulatory regimen, including rituximab, sirolimus, and corticosteroids, alongside enhanced eligibility criteria and safety monitoring. Rocket plans to provide a comprehensive update on the Danon disease program during a virtual investor webinar on Tuesday, October 6, 2026, at 4:30 p.m. ET.
