KEYNOTE-B96 Brings Immunotherapy-Based Option to Platinum-Resistant Ovarian Cancer

In an interview during 2026 SGO Annual Meeting, Bradley Monk, MD, spoke about the final results of the phase 3 KEYNOTE-B96 trial in recurrent platinum-resistant ovarian cancer.

Final results from the phase 3 ENGOT-ov65/KEYNOTE-B96 trial (NCT05116189) evaluated the addition of pembrolizumab (Keytruda) vs placebo to weekly paclitaxel, with or without bevacizumab (Avastin), in patients with recurrent platinum-resistant ovarian cancer (PROC).

Patients with PROC who experience disease recurrence within 6 months of platinum-based therapy face limited effective treatment options. Weekly paclitaxel, frequently combined with bevacizumab, has remained a standard of care since the phase 3 AURELIA trial (NCT00976911) supported its approval in 2014.

The KEYNOTE-B96 trial aimed to build on this backbone by introducing immunotherapy. In this randomized, double-blind phase 3 study of 643 patients, participants received weekly paclitaxel plus either pembrolizumab or placebo. Bevacizumab was included in approximately 75% of eligible patients. Findings, published in The Lancet in April 2026, showed a clinically meaningful improvement in median overall survival of 4.2 months with the pembrolizumab-based regimen compared with standard therapy in patients with PD-L1–positive tumors, marking the longest survival reported in this setting to date.

Although prior immunotherapy trials in unselected populations yielded negative results, these data suggest that checkpoint inhibition can be effective when applied in the appropriate context, particularly in platinum-resistant disease and biomarker-selected patients. Outcomes were further supported by PD-L1 expression measured using the 22C3 companion diagnostic assay, with combined positive score (CPS) thresholds helping to identify patients most likely to benefit. These results contributed to the FDA approval of pembrolizumab in combination with paclitaxel, with or without bevacizumab, for this indication in February 2026.

Overall, incorporating pembrolizumab into standard chemotherapy regimens represents a meaningful step forward, improving survival and broadening treatment options for patients with recurrent platinum-resistant ovarian cancer.