Pembrolizumab (PD-1) ± carboplatin/pemetrexed shows manageable grade≥3 toxicity in ≥70yo lung adenocarcinoma

Pembrolizumab is an anti–PD-1 checkpoint inhibitor; here it was given first-line as monotherapy or with carboplatin+pemetrexed in a national, nonrandomized open-label Phase II trial in adults aged ≥70 years with stage IV/recurrent lung adenocarcinoma (Alliance A171901; NCT04533451). In 95 evaluable patients (median age 77; 11.6% ECOG ≥2), solicited grade≥3 AEs within 6 months occurred in 25.6% (95% CI 13.5-41.2) with pembrolizumab alone vs 42.3% (95% CI 28.7-56.8) with pembrolizumab+chemo; median OS was 16.4 months (95% CI 10.1-NE) vs 29.9 months (95% CI 16.4-NE), respectively, while QOL worsened during treatment and a geriatric assessment toxicity risk score did not correlate with severe AEs. For a rough efficacy benchmark, randomized KEYNOTE-189 reported mOS 22.0 months with pembrolizumab+pemetrexed/platinum (vs 10.7 months with chemo) in a broader (not older-adult–restricted) metastatic nonsquamous NSCLC population, while KEYNOTE-024 in PD-L1 TPS ≥50% reported pembrolizumab monotherapy mOS 26.3 months (vs 13.4 months with chemo)—so this older-adult dataset looks directionally consistent on toxicity, but OS is hard to compare given nonrandomized treatment selection and unknown PD-L1/driver makeup here.