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News
A dual immunotherapy combo is turning heads in recurrent ovarian cancer. Updated data from the phase 1b C-800-01 trial show that botensilimab plus balstilimab achieved a 48% estimated 3-year overall survival rate in heavily pretreated patients — unchanged from the 2-year mark — suggesting a durable survival plateau even in patients who had exhausted most treatment options.
A dual immunotherapy regimen is showing staying power in one of oncology's toughest-to-treat cancers. Three-year follow-up data from the phase 1b C-800-01 trial, presented at the 2026 International Gynecologic Cancer Society Annual Global Meeting, reveal that botensilimab (a CTLA-4–directed antibody) plus balstilimab (an anti–PD-1 antibody) achieved a 48% estimated 3-year overall survival (OS) rate in heavily pretreated recurrent ovarian cancer — a figure that held steady from the 2-year estimate, hinting at a meaningful survival plateau.
Notably, 25% of all treated patients were alive and had stopped all therapy at last follow-up, a striking finding given that the median number of prior treatment lines was 4. Responses were observed across both platinum-sensitive and platinum-resistant/refractory disease, with the latter group — typically harder to treat — achieving a 47% 3-year OS rate. No new safety signals or treatment-related deaths were reported.
By the Numbers:
Why it matters: Recurrent ovarian cancer after multiple lines of therapy has very few effective options, and immunotherapy has historically underperformed in this setting. A stable survival plateau at 3 years — especially in platinum-resistant disease — could signal a meaningful shift in how immune-based approaches are used in gynecologic oncology.
