A phase 3 randomised, double-blind trial published in The Lancet has evaluated the addition of pembrolizumab to weekly paclitaxel, with or without bevacizumab, in patients with platinum-resistant recurrent ovarian cancer.
Platinum-resistant ovarian cancer remains a high unmet need, with limited effective treatment options and historically poor survival outcomes. In the ENGOT-ov65/KEYNOTE-B96 study, patients with platinum-resistant recurrent disease who had received one to two prior systemic regimens were randomised to receive pembrolizumab or placebo in combination with weekly paclitaxel. Bevacizumab was permitted at the investigator’s discretion in eligible patients.
CLINICAL SUMMARY
What was examined
A phase 3 randomised trial evaluated pembrolizumab plus weekly paclitaxel (with or without bevacizumab) versus chemotherapy alone in patients with platinum-resistant recurrent ovarian cancer.
Key findings
- The addition of pembrolizumab was associated with improved progression-free survival.
- Overall survival was also significantly improved, with a modest effect size
- The safety profile was consistent with known treatment-related effects
Clinical implications
- Immunotherapy combined with chemotherapy may represent a treatment approach in platinum-resistant ovarian cancer.
- Findings address a longstanding unmet need in a difficult-to-treat population.n
- Considerations around access, toxicity, and patient selection will be important for implementation. on
The primary endpoint of the study was progression-free survival, with overall survival as a key secondary endpoint. At the interim analysis, the addition of pembrolizumab was associated with a statistically significant improvement in progression-free survival compared with chemotherapy alone.
In the final analysis, overall survival was also significantly improved, with a modest reduction in the risk of death. These findings represent an important signal in a disease setting where survival gains have historically been limited.
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The study builds on prior attempts to incorporate immunotherapy into ovarian cancer treatment, which have generally shown limited benefit when used as monotherapy. The combination approach—pairing immune checkpoint inhibition with chemotherapy—may enhance antitumour activity by modulating the tumour microenvironment and increasing immunogenicity.
The safety profile of the regimen was consistent with the known effects of the individual agents, with no unexpected safety signals identified.
While these findings are encouraging, the authors note that integration into clinical practice will require careful consideration of patient selection, toxicity, and access to immunotherapy in this setting.
From a clinical perspective, the results add to the growing body of evidence evaluating immunotherapy-based combinations in resistant disease settings.
Paper: Colombo N, Zsiros E, Parma G et al. Pembrolizumab plus weekly paclitaxel in platinum-resistant recurrent ovarian cancer (ENGOT-ov65/KEYNOTE-B96): a multicentre, randomised, double-blind, phase 3 study. The Lancet, 2026; 407, 1525-1537. Access online here.
