Abcuro raised $66 million in a Series D financing to support a registrational clinical study for ulviprubart, its monoclonal antibody targeting cytotoxic T cells in inclusion body myositis (IBM). The clinical-stage company said IBM remains without FDA-approved therapies and is characterized by progressive muscle weakness driven by autoimmune cytotoxic T-cell activity. The funding—led by New Leaf Venture Partners with participation from other life sciences investors—comes as Abcuro looks to build on signals from its Phase II/III MUSCLE study (NCT05721573). While the overall study did not meet its primary endpoint, Abcuro reported a pre-specified subgroup trend supporting continued development. Abcuro plans preparations to initiate a clinical trial in the fourth quarter of 2026, using ulviprubart’s selective immune-cell depletion approach designed to preserve broader immune function while aiming to slow disease progression.