Notice Regarding Discontinuation of Development of GYM329 (emugrobart) for Spinal Muscular Atrophy and Facioscapulohumeral Muscular Dystrophy

Overview of Development Discontinuation

Chugai Pharmaceutical has decided to discontinue clinical development of the anti-latent myostatin sweeping antibody emugrobart (GYM329), developed by Roche, for spinal muscular atrophy (SMA) and facioscapulohumeral muscular dystrophy (FSHD). This decision is based on data evaluations from the Phase II/III MANATEE trial (SMA) and the Phase II MANOEUVRE trial (FSHD), which did not demonstrate consistent or robust muscle mass increase or motor function improvement, and thus lacked sufficient evidence to proceed to Phase III trials. There were no safety issues observed and tolerability was favorable.

Future Outlook and Impact

Clinical trials of emugrobart targeting obesity will continue based on scientific rationale, so this development discontinuation does not affect the obesity indication. There is no impact on the consolidated earnings guidance for the fiscal year ending December 2026. Since obesity differs from neuromuscular diseases and involves a different mechanism of action for the anti-myostatin antibody, the Phase II trial will proceed as planned.