The U.S. Food and Drug Administration (FDA) has approved KEYTRUDA and KEYTRUDA QLEX, in combination with paclitaxel with or without bevacizumab, for certain adults with PD-L1 positive (CPS ≥1) platinum-resistant epithelial ovarian, fallopian tube or primary peritoneal carcinoma.
The approval applies to patients who have received one or two prior systemic treatment regimens and whose tumours test positive for PD-L1 using an FDA-authorised test. The regimens are the first and only PD-1 inhibitors approved in the U.S. for platinum-resistant disease in this patient population.
The decision is based on results from the Phase 3 KEYNOTE-B96 trial, also known as ENGOT-ov65, which were presented at the 2025 European Society for Medical Oncology Congress. In patients with PD-L1 positive tumours, the pembrolizumab-based regimen reduced the risk of disease progression or death by 28% compared with placebo plus paclitaxel with or without bevacizumab. The trial also showed a 24% reduction in the risk of death.
Median progression-free survival was 8.3 months in the pembrolizumab group compared with 7.2 months in the control arm. Median overall survival was 18.2 months versus 14.0 months, respectively.
The study enrolled 643 patients regardless of PD-L1 status, with 72% found to have PD-L1 positive tumours. Nearly three-quarters of participants received bevacizumab during the trial, and 46% had prior exposure to the drug. Almost half had a platinum-free interval of less than three months.
The effectiveness of KEYTRUDA QLEX was established based on evidence from studies conducted with KEYTRUDA, along with additional pharmacokinetic, efficacy and safety data comparing the two formulations.
Safety findings were consistent with the known profile of pembrolizumab-based therapy. Serious adverse reactions occurred in 54% of patients receiving the combination regimen. Fatal adverse reactions were reported in 3.9% of patients. The most common adverse events included diarrhoea, fatigue, nausea, alopecia, peripheral neuropathy and urinary tract infection. Laboratory abnormalities frequently observed included anaemia, leukopenia and decreased neutrophil counts.
KEYTRUDA QLEX is contraindicated in patients with known hypersensitivity to berahyaluronidase alfa, hyaluronidase or any of its components. Both products carry warnings for severe and potentially fatal immune-mediated adverse reactions affecting multiple organs, infusion-related reactions, transplant-related complications, embryo-fetal toxicity and increased mortality in certain multiple myeloma regimens.
The approval marks an expansion of immunotherapy options for patients with platinum-resistant ovarian cancer, a setting where treatment options are limited and outcomes have historically been poor.
