Roche announced on Mar. 20 that it will stop developing its anti-myostatin therapy emugrobart for spinal muscular atrophy after the treatment did not show the expected improvements in clinical trials. The decision follows mid-stage data from the Phase 2/3 MANATEE study, which combined emugrobart with Roche's existing SMA drug Evrysdi and enrolled 259 patients.
The move is significant for patients with spinal muscular atrophy, as it reduces immediate options for new therapies but may create opportunities for other companies working in this area. According to Roche’s subsidiary Genentech, the decision was “difficult” and based on data showing that emugrobart “did not consistently deliver the improvements we hoped for in muscle growth and motor function.” The company emphasized that safety concerns were not a factor, stating that emugrobart was well-tolerated and did not cause patients to drop out of the study.
Roche said it would share a more detailed analysis of the MANATEE trial at an upcoming scientific congress. In its letter to patients, Roche wrote, “We recognize this news will be disappointing to the SMA community,” and thanked participants, caregivers, and others involved in the trial. Patients currently enrolled will transition from emugrobart to Evrysdi treatment.
In addition to ending development for SMA, Roche also discontinued work on emugrobart for facioscapulohumeral muscular dystrophy due to similar lackluster results. However, Roche continues to test emugrobart as a potential obesity treatment in a separate mid-stage study, with regulatory filings expected by 2028.
Industry analysts say this decision could benefit competitors such as Scholar Rock, which is developing apitegromab—another myostatin blocker—for SMA. Truist Securities analysts told investors that without competition from Roche’s drug, Scholar Rock could have “no competition for future market share in the anti-myostatin/muscle-enhancing SMA space.” BMO Capital Markets analysts added that "as CMC issues near resolution, investor focus is likely beginning to shift to the commercial opportunity and potential initial sales for apitegromab in SMA—and on this front, Roche’s pullout could be a boon for Scholar Rock." Apitegromab previously faced regulatory delays due to manufacturing issues unrelated to efficacy or safety.
Roche also reported discontinuing a mid-stage study of its RIPK1 inhibitor flizasertib for acute kidney injury following early data suggesting no significant clinical benefit.
