Series A · Biotech

Solstice Oncology raises $225m Series A for cancer immunotherapy

RA Capital Management led the financing to advance porustobart in two clinical indications.

Testing an immune therapy before surgery

Solstice is developing porustobart, a second-generation, Fc-enhanced CTLA-4 antibody, for use with pembrolizumab before surgery. The company is evaluating the combination in a Phase 2 trial for stage II–III microsatellite-stable colon cancer and a second undisclosed indication.

Solstice focuses on the neoadjuvant setting, where treatment is given before an operation. The company says the Series A will advance porustobart across both indications; the candidate remains in clinical development.

Use of funds

Advance lead candidate porustobart in two clinical indications

Funding history

Series A · This round$225M

Sources

  1. Solstice Oncology Raises $225M in Series A Fundingfinsmes.com · Sep 9, 2026
  2. solsticeoncology.com
  3. solsticeoncology.com