Roche Discontinues Emugrobart Development In SMA And FSHD After Efficacy Review, Myostatin Antibody Fails To Advance In Neuromuscular Trials

Chugai Pharmaceutical Co., Ltd. announced that Roche has discontinued clinical development of GYM329 (emugrobart), an investigational anti-latent myostatin sweeping antibody, for spinal muscular atrophy (SMA) and facioscapulohumeral muscular dystrophy (FSHD). The decision follows an internal review of mid- to late-stage clinical trial data.

The move comes after evaluation of results from the Phase II/III MANATEE study and the Phase II MANOEUVRE study. Although emugrobart demonstrated good tolerability and confirmed biological activity by lowering mature myostatin levels, it did not deliver sufficiently great or consistent improvements in muscle growth or functional outcomes to justify advancement into Phase III programs.

Across both studies, the therapy maintained a favourable safety profile, with no serious adverse events or treatment discontinuations due to safety concerns. The companies clarified that the development halt was driven by efficacy considerations rather than safety concerns.

Development of emugrobart for obesity remains unaffected. The companies noted that obesity differs fundamentally from neuromuscular disorders in disease biology and myostatin dynamics, providing a stronger scientific rationale for continued investigation. Phase II studies in obesity will proceed as planned. The decision is not expected to affect Chugai’s consolidated financial outlook for the fiscal year ending December 2026.