Dyne Therapeutics Launches 72-Week Phase 3 FORZETTO Trial in 90 Duchenne Muscular Dystrophy Patients
Dyne Therapeutics has begun its global 72-week Phase 3 FORZETTO trial enrolling approximately 90 Duchenne muscular dystrophy patients amenable to exon 51 skipping, with primary endpoint change in rise-from-floor velocity at Week 73. The trial, designed to support a BLA for U.S. accelerated approval, aligns with FDA guidance.
1. Trial Initiation
Dyne Therapeutics has activated the first site for its global FORZETTO Phase 3 trial, targeting approximately 90 ambulatory male participants aged 4 to 18 with Duchenne muscular dystrophy amenable to exon 51 skipping. Participants will be randomized 1:1 to receive 20 mg/kg of z-rostudirsen or placebo intravenously every four weeks over a 72-week treatment period.
2. Study Design
The randomized, placebo-controlled, double-blind trial will measure efficacy, safety and tolerability of z-rostudirsen administered at 20 mg/kg Q4W. Following completion of the placebo-controlled period, participants may enroll in a 96-week open-label extension to evaluate long-term safety and functional durability.
3. Endpoints and Preliminary Data
The primary endpoint is change from baseline in rise-from-floor velocity at Week 73, reflecting muscle strength and motor coordination. Secondary endpoints include stride velocity (95th percentile), North Star Ambulatory Assessment score, 10-meter walk/run velocity, four-stair climb velocity, forced vital capacity percent predicted and patient-reported outcomes, building on Phase 1/2 data showing a 0.04 rise/sec improvement at six months.
4. Regulatory Pathway
FORZETTO’s design is aligned with FDA guidance to serve as the confirmatory trial for converting accelerated approval to traditional approval in the U.S. and to support marketing applications outside the U.S., with Biologics License Application submission planned later this quarter based on DELIVER trial results.