CRANBURY, N.J. — October 7, 2026
Rocket Pharmaceuticals, Inc. (NASDAQ: RCKT) outlined development milestones and updated clinical findings for RP-A501, its investigational gene therapy for Danon disease, following an investor webinar held on October 6. The company detailed its FDA-aligned pivotal Phase 2 trial, which will evaluate a recalibrated dose of RP-A501 in 12 male patients. Trial success requires at least seven patients to meet both co-primary endpoints at 12 months: myocardial LAMP2 protein expression of at least Grade 1 and a reduction of at least 10% in left ventricular mass index from baseline. These endpoints are intended to support a potential accelerated approval pathway.
Modified Protocol Reports Preliminary Safety Findings
Rocket reported that the first three patients treated under the modified protocol completed the initial observation period without clinical or laboratory evidence of thrombotic microangiopathy (TMA) or capillary leak syndrome (CLS). These preliminary findings reflect the company’s revised dosing strategy, updated immunomodulation regimen and enhanced safety monitoring, introduced following safety concerns in the original-dose Phase 2 study. The earlier study included a fatal serious adverse reaction, which informed the changes to the treatment protocol. Follow-up of patients receiving the recalibrated dose remains ongoing, and the initial observations do not establish long-term safety.
Long-Term Phase 1 Data Show Sustained Cardiac Activity
In the principal Phase 1 analysis, all six patients demonstrated myocardial LAMP2 protein expression and at least a 10% reduction in left ventricular mass index at approximately 12 months. During longer-term follow-up of approximately three to seven years, five of six patients maintained left ventricular mass index below baseline, while four achieved reductions of at least 10%. All six patients also showed sustained reductions in cardiac biomarkers and reported quality-of-life improvements. In the original-dose Phase 2 study, three of four patients with longitudinal efficacy assessments achieved at least a 10% reduction in left ventricular mass index. These findings provide clinical evidence of sustained biological activity, although the studies involved small patient populations.
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Rocket Targets 2027 Dosing Completion and 2028 Results
Rocket expects to complete dosing in the pivotal Phase 2 trial by mid-2027, with topline results anticipated in mid-2028. The company’s initial target population is males with symptomatic hypertrophic cardiomyopathy associated with Danon disease. RP-A501 uses an adeno-associated virus serotype 9 (AAV9) vector to deliver a functional version of the LAMP2B gene through a single intravenous infusion. Danon disease is a rare inherited disorder that can cause progressive cardiac dysfunction and other organ complications. RP-A501 remains investigational and holds several U.S. FDA designations, including Regenerative Medicine Advanced Therapy (RMAT), Fast Track, Rare Pediatric Disease and Orphan Drug designations. Its safety and efficacy have not yet been established for regulatory approval.
Source::Rocket Pharmaceuticals, press release
