NEWTON, Mass. — Abcuro, Inc., a clinical-stage biotechnology company, reported results from its Phase 2/3 MUSCLE study evaluating ulviprubart, an investigational treatment for inclusion body myositis, at a recent global medical conference.
The study, presented at the Global Conference on Myositis in Lisbon, examined ulviprubart, a monoclonal antibody designed to target cytotoxic T cells linked to muscle damage in the disease. Inclusion body myositis is a rare, progressive autoimmune condition with no approved treatments.
While the trial did not meet its primary endpoint of statistical significance, results showed a trend toward slower disease progression compared with placebo, particularly among patients with less severe disease at baseline.
In the overall study population, patients receiving the lower dose of ulviprubart experienced a smaller decline in functional scores compared with placebo. In a pre-specified subgroup of patients with less severe disease, both dose groups showed a roughly 50 percent slowing of disease progression relative to placebo over 76 weeks.
“A trend towards slowing of disease progression in patients with less severe disease is encouraging based on the biological hypothesis of how KLRG1+ T cells destroy muscle fibers over time. This pattern is consistent with observations in other diseases, where therapeutic effects are more readily detected in earlier stages,” said Namita Goyal, M.D., Director of the Neuromuscular Center at the University of California, Irvine School of Medicine, and principal investigator of the MUSCLE study. “It also underscores ulviprubart’s unique mechanism targeting highly differentiated cytotoxic T cells expressing KLRG1. IBM is a devastating, progressive disease with no approved treatment options that affects tens of thousands of patients around the world. The significant unmet need in IBM cannot be overstated, and patients, care partners, and healthcare providers are united in seeking a safe and effective treatment.”
The trial enrolled 272 patients globally, randomized across two dosing groups and a placebo group. The primary endpoint measured changes in the IBM Functional Rating Scale over 76 weeks, with additional secondary measures assessing muscle strength and mobility.
Ulviprubart demonstrated a favorable safety and tolerability profile, with adverse events broadly comparable to placebo. The most common reported event was falls, while other side effects included chills, headache, fever, and nasopharyngitis. No patients discontinued treatment due to adverse events, and fewer patients in the treatment groups exited the study early compared with placebo.
Nearly all participants who completed the trial have continued into an ongoing open-label extension study, the company said.
“We would like to thank all the participating patients and care partners, along with the clinical investigators and their staff for their support of the MUSCLE study,” said H. Jeffrey Wilkins, Chief Medical Officer of Abcuro. “While the study did not achieve statistical significance, ulviprubart was generally well-tolerated and demonstrated a promising trend toward slowing of disease progression in less severe patients as assessed by IBMFRS. Based on the data, we believe ulviprubart has the potential to provide meaningful therapeutic benefit in such patients and we plan to meet with the FDA to discuss next steps for the advancement of ulviprubart in IBM.”
