Abcuro announced results today from its Phase 2/3 MUSCLE trial of ulviprubart (ABC008) in inclusion body myositis (IBM). In the full trial population, the study did not meet its main goal or key secondary goals. The main goal was change in IBM Functional Rating Scale (IBMFRS) score at Week 76.
Update: For a fuller discussion of the detailed ulviprubart clinical trial results, see the later March 26, 2026 article.
At the same time, the company reported a more encouraging finding in patients who started the study with mild to moderate disease. In that group, Abcuro said patients showed improvement trends on IBMFRS and other major measures, which the company believes supports continuing development of the drug for people earlier in the disease course.
Abcuro also reported that ulviprubart had a favorable safety and tolerability profile compared with placebo, and no safety concerns were identified at the doses studied.
The MUSCLE study enrolled 272 patients worldwide and tested two dose levels of ulviprubart versus placebo. Key secondary measures included manual muscle testing and dynamometry measures such as grip and quadriceps strength. Abcuro said nearly all patients who completed the study have continued into the open-label extension.
Abcuro plans to present the trial data at the 6th Global Conference on Myositis in Lisbon (March 23–26, 2026) and said it plans to discuss next steps with the FDA.
For the IBM community, this is a mixed update: the overall results were disappointing, but the safety findings and the results in patients with less advanced disease suggest ulviprubart may still have a future in IBM.
Abcuro press release announcing the ulviprubart in IBM clinical trial results
More information about inclusion body myositis clinical trials
Kevin Dooley, MD
February 24, 2026