First Participant Treated in Trial of Losmapimod for Facioscapulohumeral Muscular Dystrophy 

The first participant has received treatment in the phase 3 REACH trial (NCT05397470) of losmapimod (Fulcrum Therapeutics, Cambridge, MA) for potential treatment of facioscapulohumeral muscular dystrophy (FSHD). 

The primary efficacy endpoint is the absolute change from baseline in reachable workspace (RWS), which is a quantitative, functional measurement of FSHD progression. RWS correlates closely with how people living with the FSHD feel and function in a real-world setting. 

Secondary endpoints include muscle fat infiltration (MFI), an indicator of muscle health; Patient Global Impression of Change (PGIC); and Quality of Life in Neurological Disorders of the upper extremity (Neuro QoL UE). 

“The results from the phase 2 study confirm the potential of losmapimod to be the first disease-modifying therapy for FSHD,” said Judy Dunn, PhD, president of research and development, Fulcrum. “Based on input from patients, regulatory agencies, and the clinical community, we selected RWS as the primary efficacy measure in order to most effectively quantify the impact of losmapimod on slowing disease progression.” 

Losmapimod is an investigational, selective p38α/β mitogen activated protein kinase (MAPK) inhibitor. The randomized, placebo-controlled trial will enroll approximately 230 adults at more than 30 sites. Participants in this study are being randomly assigned to receive either losmapimod, (15 mg tablet twice/day) or placebo for 48 weeks. 
Losmapimod has been studied in more than 3,600 people across multiple indications and has been found to be generally safe and well-tolerated.