International researchers present promising phase 3 trial results of an immunotherapy for platinum-resistant ovarian cancer
At the 2025 European Society for Medical Oncology Congress in Berlin this October, researchers, led by Professor Nicoletta Colombo from the University of Milan-Bicocca, presented the significant results of the KEYNOTE-B96 phase 3 trial.
The trial tested the effectiveness of an immunotherapy called pembrolizumab, in combination with chemotherapy, in boosting progression-free-survival (the duration after a treatment that a patient’s disease does not get worse or progress).
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Focusing on patients whose ovarian cancer is resistant to platinum-based chemotherapy, and who therefore urgently require new treatment options, the team conducted a trial with 643 patients. Eligible participants were required to have confirmed epithelial ovarian, fallopian tube, or primary peritoneal carcinoma. They also needed to have previous treatment for ovarian cancer and have radiographic evidence that their cancer had progressed within 6 months following platinum-based chemotherapy. Of these participants 322 were randomly assigned the pembrolizumab combination while others received a placebo.
Results demonstrated that an additional four months of progression-free survival was achieved with this new treatment strategy, which also boosted overall survival to 18.2 months, potentially offering new hope for patients who do not benefit from currently available treatments.
This treatment also appeared effective for different types of ovarian cancer, with 86% of participants diagnosed with high-grade serous, and 7.8% with clear cell ovarian cancer.
Why is this study important and what could it mean for people with ovarian cancer?
This study is promising news for patients with platinum-resistant ovarian cancer, for whom current standard-of-care treatments are no longer effective.
Immunotherapies have typically been considered effective only in a small proportion of for ovarian cancers, but this study demonstrates that it could be beneficial for more people with ovarian cancer. This treatment combination could provide clinicians with a new option for their patients in the future.
The company behind this treatment, Merck, has now filed for Federal Drug Administratoin (FDA) approval. The OCRF looks forward to the release of final trial results and further understanding of overall survival long-term.
Momentum builds for treatments targeting those with platinum-resistant ovarian cancer
This new data comes amidst other trial releases that offer hope for platinum-resistant ovarian cancers.
A smaller phase 2 trial with 40 participants recently showed that the treatment Stenoparib increased overall survival by approximately 25 months due to its ability to stop cancer using two key pathways it relies upon.
Additionally, the phase 3 ROSELLA trial tested whether adding a compound called relacorilant, to chemotherapy improved the effectiveness of chemotherapy in high-grade serous, platinum-resistant ovarian cancer. Results published in The Lancet research journal demonstrated that the overall survival was increased by approximately four months for the 188 patients that received the combination treatment.
Collectively, these trial advances indicate building momentum in treatments for platinum-resistant ovarian cancer and the OCRF hopes to see new options, like these, fast-tracked to the clinic where they are urgently needed.
References:
- Hear from the lead researcher outlining their findings
- KEYNOTE-B96 trial: Colombo N, Zsiros E, Sebastianelli A, et al. Pembrolizumab vs placebo plus weekly paclitaxel ± bevacizumab in platinum-resistant recurrent ovarian cancer: results from the randomized double-blind phase III ENGOT-ov65/KEYNOTE-B96 study. Presented at: 50th European Society for Medical Oncology Congress; October 17-21, 2025; Berlin, Germany. Abstract LBA3.
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