KEYLYNK-001: a maintenance benefit in BRCA non-mutated ovarian cancer

Design

Phase 3, randomised, double-blind, placebo-controlled trial

Population

1,367 women with advanced BRCA non-mutated epithelial ovarian cancer

Primary outcome

Progression-free survival

Effect

Pembrolizumab-olaparib vs control hazard ratio 0.71 (95% CI 0.61-0.84) in ITT

First-line maintenance olaparib is established for BRCA-mutated ovarian cancer, but most patients are BRCA non-mutated. KEYLYNK-001 tested adding immunotherapy and a PARP inhibitor for them, randomising 1,367 women with advanced BRCA non-mutated disease to chemotherapy with or without pembrolizumab, followed by maintenance combinations.

The winning arm was pembrolizumab plus chemotherapy followed by pembrolizumab-olaparib maintenance, which improved progression-free survival versus chemotherapy alone (intention-to-treat hazard ratio 0.71, and 0.66 in the PD-L1-high group). Tellingly, pembrolizumab added to chemotherapy without olaparib maintenance did not significantly help, so the benefit rests on the olaparib-containing maintenance. Grade 3 or higher and serious adverse events were more frequent with the active regimen.

The practical read is that a pembrolizumab-olaparib maintenance strategy is a promising first-line option for BRCA non-mutated advanced ovarian cancer, at the cost of more toxicity, and that pembrolizumab alone is not the active ingredient. This is a progression-free survival benefit; overall survival is not yet established.

• Phase 3 trial of 1,367 women with advanced BRCA non-mutated epithelial ovarian cancer.
• Pembrolizumab-olaparib maintenance improved progression-free survival (ITT hazard ratio 0.71).
• The benefit was larger in PD-L1-high disease (hazard ratio 0.66).
• Pembrolizumab added without olaparib maintenance did not significantly help.
• Grade 3 or higher and serious adverse events were more frequent with the active regimen.

Why it matters

It extends a maintenance benefit to the BRCA non-mutated majority, and shows the effect comes from olaparib, not pembrolizumab alone.

Don't overread it

This is a progression-free survival benefit, not proven overall survival, and the regimen adds meaningful toxicity.

The statistics, in plain English

A hazard ratio of 0.71 means about a 29% lower rate of progression or death over time. That the pembrolizumab-only arm was non-significant (hazard ratio 0.95) tells you the olaparib-containing maintenance, not the immunotherapy alone, drove the result.

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