Abcuro Completes Enrollment for Phase 2/3 Trial of Ulviprubart in Inclusion Body Myositis

Abcuro, Inc., a biotechnology firm based in Newton, Massachusetts, has recently completed the enrollment phase of its registrational Phase 2/3 MUSCLE clinical trial. This trial is designed to evaluate the efficacy of ulviprubart (ABC008) in treating inclusion body myositis (IBM), a debilitating autoimmune disease that currently lacks effective treatment options.

Chief Medical Officer of Abcuro, Dr. H. Jeffery Wilkins, emphasized the importance of this milestone. According to Dr. Wilkins, ulviprubart is a groundbreaking therapy targeting KLRG1 and has the potential to significantly change the treatment landscape for IBM patients. He also mentioned that initial data from this trial would likely be available in the first half of 2026.

Inclusion body myositis is a disease that severely impacts the quality of life of those affected. Paula J. Eichenbrenner, Executive Director of The Myositis Association, noted the profound effect IBM has on patients and their families. She highlighted the need for a disease-modifying treatment, pointing out that current therapies like exercise and physical therapy can only offer limited relief. The absence of effective treatments places a heavy burden on families, who must help their loved ones manage both the physical and emotional challenges of the disease.

The Phase 2/3 MUSCLE clinical trial (NCT05721573) is being conducted globally across multiple centers. It is a randomized, double-blind, placebo-controlled trial that will assess the efficacy, safety, and tolerability of two dosage levels of ulviprubart (0.5 mg/kg and 2.0 mg/kg) compared to a placebo over a 76-week period. Following this period, there will be an additional 4-week safety follow-up.

Ulviprubart (ABC008) is an innovative anti-KLRG1 antibody that selectively targets highly cytotoxic T cells while sparing other types of T cells, such as naïve, regulatory, and central memory T cells. This selective targeting makes ulviprubart a promising candidate for treating diseases driven by highly cytotoxic T cells, including IBM, T cell large granular lymphocytic leukemia (T-LGLL), and mature T cell malignancies. Both the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have granted orphan drug designation to ulviprubart for the treatment of IBM.

Inclusion body myositis is characterized by chronic attacks from highly cytotoxic T cells on muscle tissue, leading to progressive muscle weakness and atrophy. Patients often experience loss of grip, dexterity, and mobility. Current treatment options are limited, focusing mainly on managing symptoms rather than altering the course of the disease. Published epidemiology studies estimate that more than 50,000 people in the US and Europe suffer from IBM.

Abcuro specializes in developing first-in-class immunotherapies aimed at treating autoimmune diseases and cancer by precisely modulating highly cytotoxic T cells. The company’s leading program, ulviprubart, is currently undergoing clinical trials for both IBM and T cell large granular lymphocytic leukemia.

This development marks a significant advance for IBM patients and their families, offering hope for what could become the first effective treatment for this challenging disease.