Publication of results from phase IIb clinical trial of losmapimod in facioscapulohumeral muscular dystrophy (ReDUX4) in The Lancet Neurology

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.

“The publication of these results, which informed the design and choice of efficacy endpoints in our Phase III clinical trial, also provide important validation for the therapeutic potential of losmapimod," said Patrick Horn M.D., Ph.D., Fulcrum’s chief medical officer. "Looking ahead, we remain on track to report topline data for REACH in the fourth quarter of 2024, which will bring us one step closer to addressing the high unmet needs of the FSHD patient community. With an unwavering commitment to our patients, we continue to take important steps toward a potential NDA filing and commercial launch for losmapimod.”

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 III 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 Q4 2024.

See-The Lancet Neurology- Rabi Tawil MD , Prof Kathryn R Wagner MD , Johanna I Hamel MD , Doris G Leung MD , Jeffrey M Statland MD, Prof Leo H Wang MD , Angela Genge MD , Prof Sabrina Sacconi MD , Prof Hanns Lochmüller MD David Reyes-Leiva MD , Prof Jordi Diaz-Manera MD , Jorge Alonso-Perez MD , Et al., Volume 23, Issue 5, May 2024, Pages 477-486.