NEWTON, Mass. — Abcuro, Inc. has raised $66 million in a Series D financing to support a potentially registrational clinical study of ulviprubart in patients with less severe inclusion body myositis.
The financing was led by New Leaf Venture Partners and included participation from existing investors including Bain Capital Life Sciences, Samsara BioCapital, Redmile Group, Mass General Brigham Ventures, RA Capital Management, Pontifax, Sanofi Ventures, Foresite Capital and NEA. Rock Springs Capital joined as a new investor.
Abcuro said proceeds will support a new study of ulviprubart, a first-in-class monoclonal antibody targeting killer cell lectin-like receptor G1, or KLRG1. The company expects to begin the study in the fourth quarter of 2026 following discussions with the U.S. Food and Drug Administration.
If the study is successful, Abcuro plans to submit a biologics license application to the FDA.
“We are pleased to have this opportunity to further evaluate ulviprubart in patients with IBM, a devastating progressive disease,” said Alex Martin, Chief Executive Officer of Abcuro. “We have begun preparations to initiate a clinical trial in the fourth quarter of 2026 as we continue our work to develop an effective treatment option in an indication where there is no approved therapy.”
The planned study follows results from Abcuro’s Phase 2/3 MUSCLE trial, which were presented in March 2026 at the Global Conference on Myositis.
Although the overall Phase 2/3 results were not statistically significant, Abcuro said a predefined analysis of patients with less severe disease showed a 50% slowing of disease progression compared with placebo, as measured by the Inclusion Body Myositis Functional Rating Scale.
The company also said ulviprubart demonstrated a favorable safety and tolerability profile compared with placebo.
“The MUSCLE study provided encouraging data in a pre-defined analysis of patients with less severe disease, underscoring ulviprubart’s unique mechanism of targeting highly differentiated cytotoxic T cells expressing KLRG1,” said Namita Goyal, M.D., Chief of the Neuromuscular Division at the University of California, Irvine School of Medicine.
Ulviprubart is designed to selectively target and deplete differentiated cytotoxic KLRG1-positive T cells while sparing other immune cells. Abcuro is developing the antibody for inclusion body myositis, a rare and progressive autoimmune muscle disease with no approved pharmacologic treatment.
“There is a significant unmet need for an approved treatment for IBM,” said Ron Hunt, Co-Founder and Managing Director of New Leaf Venture Partners. “We are excited to work closely with the company as it moves forward in this next chapter.”
Abcuro expects topline results from the planned clinical study in the second half of 2028.
