Merck Receives the EC Approval for Keytruda, Plus CT ± Avastin to Treat PD-L1+ Pt-Resistant Ovarian Carcinoma

Why It Matters

The clearance provides European oncologists a biomarker‑driven therapy that can extend survival for platinum‑resistant ovarian cancer patients, while strengthening Merck’s market position in immunotherapy.

Key Takeaways

• EC approves Keytruda combo for PD-L1+ ovarian cancer.
• Trial showed 28% PFS improvement, 24% OS reduction.
• Eligible patients: platinum‑resistant, 1‑2 prior therapies, CPS ≥1.
• 643 patients enrolled across 30 EU member states.
• Combination includes paclitaxel with optional Avastin.

Pulse Analysis

Ovarian carcinoma remains one of the deadliest gynecologic malignancies, with platinum‑resistant disease accounting for a large share of relapses. Historically, treatment options have been limited to cytotoxic chemotherapy, offering modest survival benefits and considerable toxicity. The emergence of immune checkpoint inhibitors, particularly pembrolizumab, has opened a pathway to harness the patient’s own immune system, but efficacy has depended on the presence of the PD‑L1 biomarker. By targeting tumors with a combined positive score of at least one, clinicians can now identify a subset more likely to respond to immunotherapy.

The Phase III KEYNOTE‑B96/ENGOT‑ov65 trial enrolled 643 women across Europe, of whom 72 % expressed PD‑L1 CPS ≥ 1. Patients received pembrolizumab 400 mg every six weeks alongside paclitaxel, with the option to add bevacizumab (Avastin). The regimen extended median progression‑free survival to 8.3 months, a 28 % gain over chemotherapy alone, and pushed median overall survival to 18.2 months, cutting the risk of death by 24 % significantly. These gains are clinically meaningful in a setting where median overall survival rarely exceeds 14 months.

The European Commission’s endorsement instantly makes the combination available in all 30 EEA markets, giving Merck a foothold in a high‑unmet‑need segment and reinforcing its immuno‑oncology pipeline. The approval also signals regulators’ willingness to accept biomarker‑driven indications, potentially accelerating future submissions for other PD‑L1‑positive cancers. For investors, the move could translate into incremental revenue as hospitals adopt the regimen alongside existing standards of care. Looking ahead, Merck may leverage this success strategically to explore pembrolizumab‑based combos in other resistant gynecologic tumors, further solidifying its position in the European oncology landscape.