Fulcrum Therapeutics Announces Complete Data from Phase 1 Trial with Losmapimod in Facioscapulohumeral Muscular Dystrophy (FSHD)

– Losmapimod achieves target engagement in muscle –

– Oral presentation at Virtual Muscular Dystrophy Association (MDA) Clinical and Scientific Conference highlights safety, tolerability and pharmacokinetics of losmapimod –

CAMBRIDGE, Mass., March 24, 2020 (GLOBE NEWSWIRE) -- Fulcrum Therapeutics, Inc. (Nasdaq: FULC), a clinical-stage biopharmaceutical company focused on improving the lives of patients with genetically defined rare diseases, today announced complete results from its Phase 1 clinical trial of losmapimod, which is being developed for the treatment of facioscapulohumeral muscular dystrophy (FSHD). Results were presented by Michelle Mellion, M.D., the Company’s senior medical director, in a live Virtual Clinical Trial Session of the Muscular Dystrophy Association (MDA) Clinical and Scientific Conference today. Presented material is available on Fulcrum’s website at fulcrumtx.com. 

The primary objective of the Phase 1 trial was to investigate the safety and tolerability of losmapimod in healthy volunteers and in FSHD patients. The secondary objective was to evaluate repeated dose pharmacokinetics (PK) and target engagement (TE), measured by phosphorylated and total HSP27, in FSHD patients in blood and muscle. In the first cohort, 10 healthy volunteers were randomized to a single oral dose of losmapimod (n=8) 7.5 mg followed by a single oral dose of 15 mg after a wash out period or to single oral dose placebo (n=2) in both dosing periods. In the second cohort, 15 FSHD patients were randomized and treated with placebo (n=3) or losmapimod 7.5 mg (n=6) or 15 mg (n=6) taken orally twice daily for 14 days. The third cohort was open label with five FSHD patients treated with losmapimod 15 mg twice daily for 14 days. Biopsies of normal appearing (second cohort) and actively involved (STIR+) muscle (third cohort) were performed at baseline and during treatment.

Dose-dependent and sustained target engagement was observed in blood with losmapimod.  Evidence of target engagement was also observed in skeletal muscle biopsies. Consistent with previously reported safety data, losmapimod was well tolerated with no serious adverse events (SAEs). Similar tolerability, safety and PK were observed in healthy volunteers and patients with FSHD at the two doses examined. This safety data is consistent with previously reported data from more than 3,500 healthy volunteers and patients treated with losmapimod across multiple other indications.