Abcuro Presents Results from Phase 2/3 MUSCLE Study of Ulviprubart in Patients with Inclusion Body Myositis at GCOM 2026

While not reaching statistical significance, there was a slowing of disease progression relative to placebo, as measured by IBMFRS, in the overall patient population at the lower dose of ulviprubart.

Mar. 27, 2026 at 6:38am

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Abcuro, Inc., a clinical stage biotechnology company, presented results at the 6th Global Conference on Myositis (GCOM) meeting from the Phase 2/3 MUSCLE clinical study of ulviprubart (ABC008), an investigational monoclonal antibody in development for the treatment of patients with inclusion body myositis (IBM). The MUSCLE study evaluated ulviprubart, dosed once every eight weeks, in patients with IBM. While the study did not achieve statistical significance, ulviprubart demonstrated a trend towards slowing of disease progression in the overall patient population at the lower dose, and a 50% slowing of disease progression relative to placebo in a pre-specified subgroup of patients with less severe disease. Ulviprubart also demonstrated a favorable safety and tolerability profile compared with placebo.

Why it matters

IBM is a rare, debilitating and relentlessly progressive chronic autoimmune disease that currently has no approved treatment options. 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 results from the MUSCLE study suggest that ulviprubart has the potential to provide meaningful therapeutic benefit, particularly in patients with less severe disease.

The details

The MUSCLE study was a global Phase 2/3 clinical trial that randomized 272 patients to one of two dose cohorts of ulviprubart (0.5 mg/kg and 2.0 mg/kg) or placebo. The primary endpoint was change from baseline in IBM Functional Rating Scale (IBMFRS) total score at Week 76. In the overall patient population, the Low Dose Cohort showed a trend for slower decline in IBMFRS compared to placebo, while the High Dose Cohort did not. In a pre-specified analysis of patients with a baseline IBMFRS score of ≥29, indicating less severe disease, both dose cohorts showed a trend towards a 50% slowing of disease progression relative to placebo. Ulviprubart was observed to have a favorable safety and tolerability profile.

  • The MUSCLE study was a global Phase 2/3 clinical trial.
  • The results were presented at the 6th Global Conference on Myositis (GCOM) meeting, held March 23-26, 2026 in Lisbon, Portugal.

The players

Abcuro, Inc.

A clinical stage biotechnology company developing potentially first-in-class immunotherapies for debilitating and progressive rare autoimmune diseases.

Ulviprubart (ABC008)

An investigational monoclonal antibody in development for the treatment of inclusion body myositis (IBM).

Namita Goyal, MD

Director of the Neuromuscular Center at the University of California, Irvine School of Medicine, and principal investigator of the MUSCLE study.

H. Jeffrey Wilkins

Chief Medical Officer of Abcuro.

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What they’re saying

“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.”

— Namita Goyal, MD, Director of the Neuromuscular Center at the University of California, Irvine School of Medicine, and principal investigator of the MUSCLE study

“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. 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.”

— H. Jeffrey Wilkins, Chief Medical Officer of Abcuro

What’s next

Abcuro plans to meet with the FDA to discuss next steps to advance ulviprubart in IBM.

The takeaway

While the MUSCLE study did not reach statistical significance, the results suggest that ulviprubart has the potential to slow disease progression, particularly in patients with less severe IBM. This provides hope for a new treatment option for this debilitating and progressive autoimmune disease that currently has no approved therapies.