- Roche discontinued development of GYM329 (emugrobart), an anti-latent myostatin sweeping antibody, for SMA and FSHD (announced Mar 23, 2026).
- Phase II/III MANATEE (Part 1) in SMA and Phase II MANOEUVRE in FSHD showed target engagement and safety but lacked consistent functional efficacy.
- Emugrobart was well tolerated with no serious adverse events or treatment withdrawals, and Phase II development in obesity will continue.
- Chugai does not expect this decision to affect its consolidated financial forecast for the fiscal year ending Dec 2026 (announced Jan 29, 2026).
Decision
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); announcement dated March 23, 2026.
Clinical results
Data from the Phase II/III MANATEE study (Part 1) in SMA and the Phase II MANOEUVRE study in FSHD showed target engagement—reduction of mature myostatin—and some muscle growth, but functional efficacy measures were inconsistent and not robust enough to support Phase III development in these neuromuscular indications.
Safety
Emugrobart was well tolerated across both studies with no serious adverse events or treatment withdrawals; discontinuation was not driven by safety concerns.
Obesity program
Roche and Chugai will continue Phase II development of emugrobart in obesity, noting a different pathophysiology (non-neurodegenerative/myopathic) and generally higher myostatin availability in that indication.
Financial impact
Chugai stated the decision is not expected to affect its consolidated financial forecast for the fiscal year ending December 2026, previously announced January 29, 2026.
