Dr Monk on the KEYNOTE-B96 Data in Recurrent Platinum-Resistant Ovarian Cancer

“[This] is the longest survival we have ever seen in platinum-resistant recurrent ovarian cancer.”

Bradley Monk, MD, medical director of Late-Phase Clinical Research at Florida Cancer Specialists & Research Institute, discussed the final analysis of the phase 3 ENGOT-ov65/KEYNOTE-B96 study (NCT05116189) evaluating pembrolizumab (Keytruda) vs placebo in combination with weekly paclitaxel, with or without bevacizumab (Avastin), for patients with recurrent platinum-resistant ovarian cancer (PROC).

Patients with PROC whose disease recurs within 6 months of platinum therapy have a limited number of effective options, Monk explained. Weekly paclitaxel, often combined with bevacizumab, has represented a long-standing standard of care (SOC) since the approval supported by the phase 3 AURELIA trial (NCT00976911) data in 2014.

KEYNOTE-B96 sought to improve upon this backbone by incorporating immunotherapy. In this randomized, double-blind phase 3 trial of 643 patients, participants received weekly paclitaxel plus pembrolizumab or placebo, with bevacizumab administered in approximately 75% of patients deemed eligible, Monk said. The results, which were published in The Lancet in April 2026, demonstrated a clinically meaningful 4.2-month improvement in median overall survival with the pembrolizumab regimen vs the SOC in the PD-L1–positive patient population—representing the longest survival reported to date in this treatment setting.

Monk emphasized that although earlier studies with immunotherapy in unselected populations were negative, this trial highlights that checkpoint inhibition can be effective when used in the appropriate clinical setting—namely, platinum-resistant disease—and in biomarker-enriched populations. The benefit observed was further supported by PD-L1 expression, as assessed by the 22C3 companion diagnostic assay, with a combined positive score (CPS) threshold enriching for responders in most patients. These findings contributed to the February 2026 FDA approval of pembrolizumab plus paclitaxel with/without bevacizumab in this setting.

Overall, the addition of pembrolizumab to standard chemotherapy, with or without bevacizumab, represents a meaningful advance that improves survival outcomes and expands treatment options for patients with PROC, Monk concluded.