Nonrandomized phase 2 trial of pembrolizumab with or without chemotherapy for advanced lung adenocarcinoma in older adults

Older adults are underrepresented in trials of immunotherapy for advanced lung cancer. The multicenter, nonrandomized phase 2 Alliance A171901 trial evaluated oncologist-choice first-line pembrolizumab with or without chemotherapy for advanced lung adenocarcinoma (LUAD) in patients aged 70 years or older. The study included 95 evaluable patients with stage IV or recurrent LUAD, of whom 43 (45.2%) started first-line pembrolizumab and 52 (54.7%) started pembrolizumab plus carboplatin and pemetrexed. Primary endpoint was proportion of patients experiencing a grade ≥ 3 adverse event (AE) within six months. This proportion was 25.6% (95% CI 13.5-41.2) in the monotherapy group and 42.3% (28.7-56.8) in the combination group. Median overall survival was 16.4 months (95% CI 10.1-NE) in the monotherapy group and 29.9 months (16.4-NE) in the combination group. The quality of life worsened during treatment. The geriatric assessment toxicity risk score was not associated with severe AEs in the combination group. The authors conclude that older adults receiving pembrolizumab plus chemotherapy for advanced LUAD had comparable AE rates to those in trials that excluded frail patients.