Abcuro Secures $200 Million to Advance Ulviprubart for Inclusion Body Myositis Treatment

Abcuro, a biotechnology company backed by Sanofi, has secured $200 million in Series C funding to advance its anti-KLRG1 antibody, ulviprubart, through a phase 2/3 clinical trial for inclusion body myositis (IBM). This investment supports the company’s broader strategy to seek regulatory approval and expand its operational capabilities.
Targeting KLRG1 is central to Abcuro’s approach to addressing autoimmune conditions by eliminating cytotoxic T cells. While other companies focus on different markers such as CD25, CD2, CD52, and ICOS, Abcuro prioritizes KLRG1 due to its specificity in affecting late-differentiated effector and effector memory T cells while sparing regulatory and central memory T cells.

Ulviprubart, also identified as ABC008, is currently undergoing clinical evaluation for IBM, a degenerative muscle disorder affecting an estimated 20,000 individuals in the United States. The company anticipates study results in the first half of 2026, with plans to submit an approval application to the U.S. Food and Drug Administration (FDA) if the findings are favorable.
In addition to progressing clinical trials, Abcuro intends to allocate funds toward scaling up manufacturing and preparing for the potential commercialization of ulviprubart. The Series C round was led by New Enterprise Associates, with participation from Foresite Capital as a new investor and continued support from existing backers, including Sanofi Ventures, RA Capital, Bain Capital Life Sciences, Redmile Group, Samsara BioCapital, Pontifax, Mass General Brigham Ventures, New Leaf Ventures, and funds managed by BlackRock.
Alex Martin, CEO of Abcuro, emphasized that the funding round underscores investor confidence in ulviprubart’s potential as an innovative treatment for conditions driven by highly cytotoxic T cells. IBM, characterized by progressive muscle weakening and loss of motor function, is associated with T-cell-mediated attacks on muscle fibers. In 2019, Abcuro co-founder and neurologist Steven Greenberg, M.D., co-authored research linking KLRG1-expressing T cells to IBM, laying the groundwork for the company’s therapeutic approach.
Mass General Brigham Ventures and Sanofi Ventures initially backed Abcuro during its Series A-1 round in 2021, building upon Greenberg’s research. Subsequently, the company secured $155 million in Series B financing in 2023, enabling further development of ulviprubart.
Beyond its IBM program, Abcuro is conducting a phase 1/2 study of ulviprubart in T-cell large granular lymphocytic leukemia (T-LGLL), a condition that leads to anemia and neutropenia, often requiring patients to undergo blood transfusions. The drug is also being explored for additional T-cell and natural killer (NK) cell-associated lymphomas.

IBM is a condition for which no FDA-approved treatments are currently available. Existing therapeutic approaches, including corticosteroids and immunosuppressants, generally show limited effectiveness. Management strategies primarily involve physical therapy, exercise, and supportive care. The ongoing MUSCLE trial, which enrolled approximately 230 participants last year, is evaluating the safety and efficacy of ulviprubart. Key outcome measures include changes in IBM Functional Rating Scale scores over a 76-week period and safety assessments at the 20-week mark.