RAHWAY, N.J., April 2, 2026
Merck (MSD) has secured a major regulatory milestone as the European Commission approves KEYTRUDA® (pembrolizumab) in combination with paclitaxel, with or without bevacizumab, for the treatment of PD-L1-positive platinum-resistant ovarian cancer, marking the first PD-1 inhibitor-based regimen approved in the European Union for this difficult-to-treat patient population. The approval is based on robust Phase 3 KEYNOTE-B96 trial data, demonstrating statistically significant improvements in both progression-free survival (PFS) and overall survival (OS), offering a critical new therapeutic option in an area of high unmet medical need.
Phase 3 Trial Confirms Survival Benefit in Resistant Disease
The KEYNOTE-B96 (ENGOT-ov65) Phase 3 trial, a randomized, double-blind, placebo-controlled study, evaluated the efficacy of KEYTRUDA-based combination therapy in patients with platinum-resistant recurrent ovarian cancer expressing PD-L1 (CPS ≥1). The results showed a 28% reduction in the risk of disease progression or death (HR=0.72; p=0.0014) and a 24% reduction in the risk of death (HR=0.76; p=0.0053) compared to standard chemotherapy regimens.
Median progression-free survival improved to 8.3 months versus 7.2 months, while overall survival increased to 18.2 months compared to 14.0 months, underscoring the clinical significance of immunotherapy integration in ovarian cancer treatment. These outcomes highlight the growing role of immune checkpoint inhibitors in addressing treatment resistance and improving patient outcomes in advanced-stage malignancies.
First-in-Class PD-1 Therapy Expands Treatment Landscape
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This approval establishes KEYTRUDA as the first and only PD-1 inhibitor-based treatment option in the EU for patients with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal carcinoma who have undergone prior systemic therapies. The regimen works by enhancing the immune system’s ability to detect and destroy tumor cells, specifically by blocking the PD-1/PD-L1 pathway, thereby activating T-cell mediated anti-tumor responses.
Given that over 80% of ovarian cancer patients experience disease progression following platinum-based chemotherapy, and a significant proportion develop resistance within six months, the availability of this immunotherapy-based combination regimen represents a transformative advancement. The approval also follows a positive opinion from the European Medicines Agency’s CHMP, further reinforcing the strength of the clinical evidence and regulatory confidence in the therapy.
Addressing High Unmet Need in Women’s Oncology
Ovarian cancer remains one of the leading causes of cancer-related deaths among women globally, with more than 324,000 new cases and approximately 207,000 deaths reported annually, and projections indicating a 42% increase in incidence by 2040. Patients with platinum-resistant disease face particularly poor prognoses, with limited effective treatment options and reduced survival outcomes.
The introduction of a KEYTRUDA-based regimen provides a much-needed innovation by combining immunotherapy with chemotherapy ± anti-angiogenic therapy, offering a multi-mechanistic approach to disease control. Additionally, Merck’s extensive immuno-oncology research program, comprising over 2,800 clinical trials, continues to expand the therapeutic reach of KEYTRUDA across multiple cancer types, reinforcing its position as a cornerstone in modern oncology treatment strategies.
With this landmark approval, Merck advances the global standard of care in ovarian cancer, delivering a clinically validated, survival-improving treatment option for patients with limited alternatives, while strengthening the role of precision immunotherapy in gynecologic oncology and paving the way for broader adoption across international healthcare systems.
Source: Merck & Co. press release
