The Phase 3 KEYLYNK-006 Study of Pembrolizumab plus Olaparib versus Pembrolizumab plus Pemetrexed as Maintenance Therapy for Metastatic Nonsquamous Non-Small-Cell Lung Cancer

Background: Poly (ADP-ribose) inhibitors, including olaparib, upregulate programmed cell death ligand 1 (PD-L1), which may increase efficacy of anti-PD-(L)1 therapies.

Methods: In the phase 3 KEYLYNK-006 trial (NCT03976323), eligible adults with previously untreated metastatic nonsquamous NSCLC without targetable genetic alterations who had complete response (CR), partial response (PR), or stable disease (SD) following induction therapy with 4 cycles of pembrolizumab 200 mg Q3W, pemetrexed 500 mg/m² , and carboplatin AUC5 or cisplatin 75 mg/m² were randomized 1:1 to olaparib 300 mg orally twice daily or pemetrexed Q3W, both given with ≤31 cycles of pembrolizumab Q3W. Dual primary endpoints were progression-free survival (PFS) and overall survival (OS). PFS was tested at interim analysis 2 (IA2; ie, final PFS analysis), OS at final analysis (FA).

Results: Of 1003 patients who received induction therapy, 672 (67.0%) were randomized to pembrolizumab plus olaparib (n=337) or pembrolizumab plus pemetrexed (n=335) in the intention-to-treat population. Median follow-up at FA was 39.9 (range, 28.1-51.5) months. At IA2, median (95% CI) PFS was 7.1 (5.6-8.7) months versus 8.3 (6.9-11.5) months in the olaparib versus pemetrexed groups (HR, 1.12; 95% CI, 0.92-1.36; P=0.87). At FA, median (95% CI) OS was 20.7 (18.0-24.8) months versus 23.0 (19.0-26.4) months (HR, 1.04; 95% CI, 0.87-1.25; P=0.6649). Grade 3-5 maintenance treatment-related AEs occurred in 26.1% versus 30.1% patients.

Conclusion: Pembrolizumab plus maintenance olaparib did not improve PFS or OS versus pembrolizumab plus pemetrexed in previously untreated metastatic nonsquamous NSCLC without targetable genetic alterations.