Doug Kerr, MD, PhD, MBA, Chief Medical Officer of Dyne Therapeutics, discusses the initiation of the phase 3 FORZETTO trial of zeleciment rostudirsen (z-rostudirsen, also known as DYNE-251), in individuals with Duchenne muscular dystrophy (DMD) amenable to exon 51 skipping.
DMD is a rare genetic, neuromuscular condition characterized by progressive muscle wasting. Symptoms of DMD include progressive weakness and atrophy of both skeletal and heart muscle. Early signs may include delayed ability to sit, stand, or walk and difficulties learning to speak. DMD is caused by genetic changes in the DMD gene.
Z-rostudirsen is an investigational therapeutic consisting of a phosphorodiamidate morpholino oligomer (PMO) conjugated to an antigen-binding fragment (Fab) that binds to the transferrin receptor 1 (TfR1). It is designed to enable the production of near full-length dystrophin in muscle and the central nervous system to provide functional improvement.
The design of the FORZETTO clinical trial was presented at the 2026 International Congress on Neuromuscular Diseases (ICNMD).
FORZETTO is a global, randomized, placebo-controlled, double-blind, confirmatory phase 3 trial designed to assess the efficacy, safety, and tolerability of z-rostudirsen administered intravenously to ambulatory male participants with DMD amenable to exon 51 skipping. The trial will enroll approximately 90 participants ages 4 to 18 years who will be randomized to receive 20 mg/kg of z-rostudirsen or placebo every four weeks. The first trial site is activated and open to enrollment.
The primary endpoint is the change from baseline to week 83 in rise from floor (RFF) velocity, or time to rise (TTR) velocity, a clinically meaningful measure of muscle strength and motor coordination. Secondary endpoints include changes from baseline in stride velocity 95th centile, North Star Ambulatory Assessment total score, 10-meter walk/run velocity, four-stair climb velocity and forced vital capacity percent predicted. Following the 72-week double-blind placebo-controlled treatment period, participants will be eligible to enroll in a 96-week open-label long-term extension.
Learn more about the clinical trial at NCT07608432 or here.
To learn more about DMD and other rare musculoskeletal conditions, visit https://checkrare.com/diseases/musculoskeletal-diseases/