The Phase 3 trial for pembrolizumab (NCT05116189) reached primary completion on 2025-03-05. The study investigated pembrolizumab in combination with paclitaxel with or without bevacizumab for platinum-resistant recurrent ovarian cancer. Key results showed that the pembrolizumab combination achieved a median progression-free survival (PFS) of 8.3 months in all participants, compared to 6.4 months for the placebo combination, with a hazard ratio of 0.73 (p=0.0001).
Background
Pembrolizumab is an intervention being studied for the treatment of platinum-resistant recurrent ovarian cancer, carcinoma, ovarian epithelial, and fallopian tube neoplasms. This Phase 3 study evaluated its efficacy when combined with paclitaxel, with or without bevacizumab.
Trial design
The KEYNOTE-B96/ENGOT-ov65 study (NCT05116189) was a Phase 3, randomized trial that enrolled 643 participants. The study investigated pembrolizumab plus paclitaxel with or without bevacizumab compared to placebo plus paclitaxel with or without bevacizumab for participants with platinum-resistant recurrent ovarian cancer, carcinoma, ovarian epithelial, and fallopian tube neoplasms. The primary objective was to compare progression-free survival (PFS) per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 as assessed by the investigator, with a hypothesis of superiority for the pembrolizumab arm, particularly in participants with programmed cell death ligand 1 (PD-L1) positive tumors (Combined Positive Score [CPS] ≥1).
Key results
The trial evaluated progression-free survival (PFS) across different participant groups and assessment methods:
- For participants with PD-L1 positive tumors (CPS ≥1), investigator-assessed median PFS was 8.3 months for the pembrolizumab combination versus 7.2 months for the placebo combination.
- In all participants, investigator-assessed median PFS was 8.3 months for the pembrolizumab combination versus 6.4 months for the placebo combination.
- When assessed by Blinded Independent Central Review (BICR) in participants with PD-L1 positive tumors (CPS ≥1), median PFS was 8.5 months for the pembrolizumab combination versus 7.6 months for the placebo combination.
- For all participants, BICR-assessed median PFS was 8.4 months for the pembrolizumab combination versus 6.4 months for the placebo combination.
Key analyses for PFS demonstrated:
- A hazard ratio (HR) of 0.75 (95% CI: 0.61 to 0.91) with a p-value of 0.0022.
- A hazard ratio (HR) of 0.73 (95% CI: 0.62 to 0.86) with a p-value of 0.0001.
- A hazard ratio (HR) of 0.75 (95% CI: 0.6 to 0.93) with a p-value of 0.0051.
- A hazard ratio (HR) of 0.74 (95% CI: 0.61 to 0.89) with a p-value of 0.0007.
What this means
The results from the KEYNOTE-B96/ENGOT-ov65 trial indicate that the addition of pembrolizumab to paclitaxel with or without bevacizumab significantly improved progression-free survival in patients with platinum-resistant recurrent ovarian cancer compared to the placebo combination. The consistent improvement in median PFS across both investigator and BICR assessments, and in both PD-L1 positive and all participant populations, suggests a potential benefit for this treatment regimen. The statistically significant hazard ratios further support the efficacy of pembrolizumab in this challenging patient population.
Source
The information regarding the primary completion and results of this trial was obtained from ClinicalTrials.gov, a public database of clinical studies. The data for study NCT05116189, titled "Pembrolizumab/Placebo Plus Paclitaxel With or Without Bevacizumab for Platinum-resistant Recurrent Ovarian Cancer (MK-3475-B96/KEYNOTE-B96/ENGOT-ov65)," was posted on 2025-03-05 on clinicaltrials.gov.