Fulcrum Therapeutics has concluded the enrolment of 260 patients in the Phase III REACH clinical trial of losmapimod to treat facioscapulohumeral muscular dystrophy (FSHD).

Patients are enrolled from the sites in Canada, Europe and the US.

The placebo-controlled, double-blind, multi-centre, randomised trial intends to assess the safety and efficacy of the p38α/β mitogen-activated protein kinase (MAPK) inhibitor losmapimod in FSHD patients.

Patients aged 18 to 65 years diagnosed with FSHD type 1 (FSHD1) or FSHD type 2 (FSHD2) will participate in Part A of the study.

They will be randomised into a 1:1 ratio to receive either a 15mg tablet or placebo orally twice a day (BID) for 48 weeks.

Absolute change from baseline in Reachable Workspace (RWS) is the primary endpoint of the study.

Secondary endpoints include a patient global impression of change, muscle fat infiltration, and Quality of Life in Neurological Disorders of the Upper Extremity (Neuro QoL UE).

After the completion of Part A, participants will have the option to participate in Part B (open-label extension).

In this study, the long-term safety, efficacy, and tolerability of losmapimod will be evaluated.

Fulcrum president and CEO Alex Sapir said: “The rapid pace of enrolment is a testament to the high unmet need for a treatment option with the potential to slow the progression of this rare disease, for which there are currently no approved treatments.

“We expect to report topline data from REACH in the fourth quarter of 2024, bringing us one step closer to potentially delivering the first FDA-approved therapy for FSHD.”

Fulcrum also plans to include patient-centred assessments of healthcare utilisation in the trial.

It exclusively in-licensed losmapimod from GSK, following its extensive review of known compounds as well as the invention of p38α/β inhibitors that helps in reducing DUX4 expression.