First-Line Pembrolizumab Efficacy in Octogenarians With NSCLCs Expressing ≥ 50% PD-L1 (ESCKEYP GFPC 05-2018)

Pembrolizumab alone is a first-line therapeutic option for patients with metastatic non-small cell lung cancer (NSCLC) with ≥ 50% PD-L1 expression, but few data are available for elderly patients, specifically octogenarians.

This retrospective, multicenter study included all consecutive patients with metastatic NSCLC PD-L1 ≥ 50% treated with first-line pembrolizumab monotherapy between May 2017 and November 2019. Information was collected from medical files with local evaluation of therapeutic response and progression-free survival (PFS).

Among the 844 patients included, 73 (8.4%) were ≥ 80 (median: 82) years old, 74% men, 23.3% with ECOG-PS ≥ 2, 26% had ≥ 5% weight loss, PD-L1 50%-75%/≥ 75%: 45.2%/46.6%, respectively, with significantly more nonsmokers and (17.4% vs. 5.6%, P = .0002) and fewer adenocarcinomas (57.5% vs. 70.8%, P = .0217) than those < 80 years. After median follow-up of 45.7 (95% CI: 43.0-49.1) months, respective median overall survival (OS) for octogenarians versus younger patients lasted 12.0 (95% CI: 7.7-16.2) versus 23.9 (95% CI: 19.5-27.4) months (P = .0002), and median PFS for 5.0 (95% CI: 2.8-9.2) versus 8.3 (95% CI: 7.2-9.8) months (P = .039). Their respective objective response rates did not differ significantly: 42% (95% CI: 24-60) vs. 49% (95% CI: 43-54).

Based on the results of this large multicenter population, first-line pembrolizumab efficacy against NSCLCs expressing ≥ 50% PD-L1 in octogenarians seems inferior to that obtained in younger patients. The higher percentage of nonsmokers and fewer adenocarcinomas could partially explain that finding.