Fulcrum Therapeutics, Inc. announced the publication of results from its Phase 2b clinical trial of losmapimod for the treatment of facioscapulopumeral muscular dystrophy (FSHD). The data are published in the peer-reviewed journal The Lancet Neurology. FSHD is a serious, rare, and progressively disabling disease characterized by fat infiltration of skeletal muscle leading to muscular atrophy involving primarily the face, shoulder girdle, upper arms, abdomen, and lower limbs.

It is caused by the aberrant expression of the DUX4 protein. It is characterized by accumulating muscle weakness and functional impairment. There are no approved disease-modifying treatments for FSHD.

While the primary endpoint of change in DUX4-driven gene expression in muscle biopsies did not show significant differences between the treatment and placebo groups, losmapimod was associated with improvements in structural and functional outcomes, including muscle fat infiltration and reachable workspace ? a measure of shoulder girdle function, and patient-reported global impression of change when compared to placebo. Losmapimod was also found to be well tolerated by trial participants.

No serious adverse events related to the drug were reported, and there were no discontinuations of treatment due to adverse events. In September 2023, Fulcrum announced the enrollment completion for the Phase 3 clinical trial evaluating losmapimod in patients with FSHD at sites in the United States, Canada, and Europe. The clinical trial remains on track with topline data expected in Fourth Quarter 2024.