HBM Holdings (02142) has announced that its partner company Solstice Oncology (Solstice) has successfully completed a $225 million Series A funding round and officially commenced operations. The financing was spearheaded by RA Capital Management, with additional participation from Canaan Partners, Forbion, and other investors.

Solstice operates as a clinical-stage oncology immunotherapy firm focused on intervening earlier in the cancer treatment timeline, specifically within the neoadjuvant setting. The company is advancing its lead candidate, prusozoab, a differentiated second-generation Fc-enhanced antibody targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). This candidate is currently being developed across two clinical indications, one being microsatellite stable (MSS) colon cancer, while the second indication remains undisclosed.

A Phase 2 clinical study is currently evaluating prusozoab in combination with pembrolizumab for the neoadjuvant treatment of clinical Stage II-III MSS colon cancer. MSS represents the most prevalent subtype of colon cancer, and to date, this patient population has not derived benefit from immunotherapy approaches. Patient enrollment for the Phase 2 trial is projected to commence in early Q4 2026, with study data anticipated in H2 2027.