Abcuro raised $66 million in a Series D financing to fund a registrational clinical study of ulviprubart for inclusion body myositis (IBM). The Newton, Massachusetts-based clinical-stage biotech is targeting a disease area with no FDA-approved therapies. The financing is expected to support preparations for a clinical trial initiation in the fourth quarter of 2026. Abcuro said Phase II/III MUSCLE (NCT05721573) did not meet its primary endpoint in the overall population, but a prespecified subgroup analysis indicated a more compelling signal. The ulviprubart program is built around a monoclonal antibody designed to selectively deplete pathogenic cytotoxic T cells thought to drive IBM muscle damage, aiming for disease-modifying control without broad immune suppression.