The U.S. Food and Drug Administration has granted approval to Merck & Co. (NYSE:MRK) for the use of KEYTRUDA and KEYTRUDA QLEX, in combination with paclitaxel, with or without bevacizumab, to treat adults with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer whose tumors express PD-L1, the company said Monday.
The authorization applies to patients who have undergone one or two prior systemic therapies and whose tumors show a Combined Positive Score (CPS) of at least 1, as confirmed by an FDA-approved diagnostic test.
The decision was supported by data from the Phase 3 KEYNOTE-B96 study, which enrolled 643 patients. Among individuals with PD-L1–expressing tumors, the KEYTRUDA-based regimen reduced the risk of disease progression or death by 28% compared with placebo plus paclitaxel, with or without bevacizumab. The treatment also lowered the risk of death by 24%.
Patients treated with the KEYTRUDA combination had a median progression-free survival of 8.3 months, versus 7.2 months in the placebo group. Median overall survival was 18.2 months for those receiving KEYTRUDA, compared with 14.0 months for patients on placebo.
In the trial population, 72% of participants had PD-L1–positive tumors, 73% were treated with bevacizumab, and 47% had a platinum-free interval of less than three months.
The approvals represent the first time a PD-1 inhibitor has been authorized for adults with platinum-resistant ovarian cancer.
Serious adverse events were reported in 54% of patients receiving the KEYTRUDA regimen. The most frequently observed serious side effects included pneumonia, urinary tract infections, and adrenal insufficiency.
KEYTRUDA QLEX is a subcutaneous version of pembrolizumab that combines the therapy with berahyaluronidase alfa, allowing it to be administered via injection rather than intravenous infusion.