On April 2, 2026 Merck (NYSE: MRK), known as MSD outside of the United States and Canada, reported that KEYTRUDA (pembrolizumab), in combination with paclitaxel, with or without bevacizumab, is approved in the European Union (EU) for the treatment of platinum-resistant epithelial ovarian, fallopian tube or primary peritoneal carcinoma in adults whose tumors express PD-L1 with a Combined Positive Score (CPS) ≥1 and who have received one or two prior systemic treatment regimens. This approval, which also covers KEYTRUDA SC [known as KEYTRUDA QLEXTM (pembrolizumab and berahyaluronidase alfa-pmph) in the U.S.], makes this regimen the first and only PD-1 inhibitor-based treatment option for eligible patients with platinum-resistant ovarian cancer in the EU.

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"Despite recent advances, patients with ovarian cancer face a significant unmet need when their disease progresses and becomes resistant to standard platinum-based therapy," said Dr. Nicoletta Colombo, director of the Gynecologic Oncology Program at the European Institute of Oncology in Milan, Italy. "The approval of this pembrolizumab-based regimen is an important advance that provides a crucial new treatment option and represents a welcome addition to the treatment landscape for appropriate patients with PD-L1-positive platinum-resistant ovarian cancer across Europe."

This approval is based on results from the Phase 3 KEYNOTE-B96 trial (also known as ENGOT-ov65), in which KEYTRUDA plus paclitaxel, with or without bevacizumab, demonstrated a statistically significant and clinically meaningful improvement in progression-free survival (PFS), the trial’s primary endpoint, and overall survival (OS), a key secondary endpoint, for patients with platinum-resistant recurrent ovarian cancer whose tumors expressed PD-L1 (CPS ≥1) compared to placebo plus paclitaxel, with or without bevacizumab. The approval follows a positive recommendation from the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP), received in February 2026.

"We’re proud to bring this KEYTRUDA-based regimen to appropriate patients in Europe with PD-L1-positive platinum-resistant ovarian cancer – giving this community access to the region’s first PD-1 inhibitor treatment approach for this disease," said Dr. Gursel Aktan, vice president, global clinical development, Merck Research Laboratories. "This milestone marks real progress for patients and advances our broader mission of expanding access to effective options for women’s cancers globally."

In the KEYNOTE-B96 trial, KEYTRUDA plus paclitaxel, with or without bevacizumab, demonstrated a statistically significant and clinically meaningful improvement in PFS, reducing the risk of disease progression or death by 28% (HR=0.72 [95% CI, 0.58-0.89]; p=0.0014) in patients with platinum-resistant recurrent ovarian cancer whose tumors expressed PD-L1 (CPS ≥1) when compared to placebo plus paclitaxel, with or without bevacizumab. For patients with platinum-resistant recurrent ovarian cancer whose tumors expressed PD-L1 (CPS ≥1) who received the KEYTRUDA-based regimen, median PFS was 8.3 months (95% CI, 7.0-9.4) versus 7.2 months (95% CI, 6.2-8.1) for patients receiving the placebo regimen.

The KEYTRUDA-based regimen also demonstrated a statistically significant and clinically meaningful improvement in OS for patients with platinum-resistant recurrent ovarian cancer whose tumors expressed PD-L1 (CPS ≥1), reducing the risk of death by 24% (HR=0.76 [95% CI, 0.61-0.94]; p=0.0053) compared to placebo plus paclitaxel with or without bevacizumab. For patients with platinum-resistant recurrent ovarian cancer whose tumors expressed PD-L1 (CPS ≥1) who received the KEYTRUDA-based regimen, median OS was 18.2 months (95% CI, 15.3-21.0) versus 14.0 months (95% CI, 12.5-16.1) for patients receiving the placebo regimen.

This approval authorizes marketing of this KEYTRUDA treatment regimen for this indication in all 27 EU member states, as well as Iceland, Liechtenstein and Norway. Timing for commercial availability of KEYTRUDA for this indication in individual EU countries will depend on multiple factors, including the completion of national reimbursement procedures.

In February 2026, KEYTRUDA plus paclitaxel, with or without bevacizumab, was approved by the U.S. Food and Drug Administration (FDA) to treat adult patients with platinum-resistant epithelial ovarian, fallopian tube or primary peritoneal carcinoma whose tumors express PD-L1 (CPS ≥1), as determined by an FDA-authorized test, and who have received one or two prior systemic treatment regimens.

About KEYNOTE-B96/ENGOT-ov65

KEYNOTE-B96, also known as ENGOT-ov65, is a multicenter, randomized, double-blind placebo-controlled Phase 3 trial (ClinicalTrials.gov, NCT05116189) sponsored by Merck and conducted in collaboration with the European Network for Gynecologic Oncology Trial (ENGOT) groups investigating KEYTRUDA, Merck’s anti-PD-1 therapy, in combination with chemotherapy (paclitaxel), with or without bevacizumab, compared to placebo plus chemotherapy with or without bevacizumab for the treatment of platinum-resistant recurrent ovarian cancer. The primary endpoint is PFS, as assessed by investigator according to Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1), and OS is a key secondary endpoint. The trial enrolled 643 patients with epithelial ovarian, fallopian tube or primary peritoneal carcinoma, regardless of PD-L1 tumor expression status, who received one or two prior lines of systemic therapy for ovarian carcinoma, including at least one line of platinum-based chemotherapy. Of the 643 enrolled patients, 72% of patients had tumors expressing PD-L1 (CPS ≥1). Patients were enrolled in KEYNOTE-B96 regardless of PD-L1 tumor expression status. Patients were randomized (1:1) to receive either KEYTRUDA plus paclitaxel, with or without bevacizumab, or placebo plus paclitaxel, with or without bevacizumab. KEYTRUDA (400 mg) or placebo were administered on Day 1 of each six-week treatment cycle and paclitaxel (80 mg/m2) was administered on Days 1, 8 and 15 of each three-week treatment cycle. The option to use bevacizumab was by investigator choice prior to randomization. Bevacizumab (10 mg/kg) was administered on Day 1 of a two-week treatment cycle.

Results from the final analysis of the KEYNOTE-B96 trial evaluating KEYTRUDA plus paclitaxel, with or without bevacizumab, including PFS and OS results for patients with platinum-resistant recurrent ovarian cancer regardless of PD-L1 status, were recently presented at the European Society of Gynaecological Oncology (ESGO) 2026 Congress.

About platinum-resistant ovarian cancer

Ovarian cancer often begins in the fallopian tubes or the ovaries. As of 2022, it is the eighth most commonly diagnosed cancer and the eighth leading cause of cancer death among women worldwide. Globally, there were more than 324,000 patients diagnosed with ovarian cancer and almost 207,000 deaths from the disease in 2022. In many regions, its incidence has been increasing, with estimates projecting a 42% increase in new cases worldwide by 2040. Over 80% of patients diagnosed with ovarian cancer will experience disease progression following standard treatment with platinum-based chemotherapy regimens. Of these patients, approximately 25% will experience disease progression within six months of completing first-line platinum-based chemotherapy – defined as primary platinum-resistant ovarian cancer. Prognosis is particularly poor for these patients and approved treatment options are limited.

(Press release, Merck & Co, APR 2, 2026, View Source [SID1234664152])