Durvalumab Plus Platinum-Etoposide in Extensive-Stage Small-Cell Lung Cancer: Outcomes in Age, Sex, and Platinum Subgroups From the Phase 3 CASPIAN Study

Introduction In the phase 3 CASPIAN study, first-line durvalumab plus etoposide combined with either carboplatin or cisplatin (EP) significantly improved overall survival (OS) versus EP alone in treatment-naïve extensive-stage small-cell lung cancer (ES-SCLC). We report exploratory subgroup analyses from CASPIAN. Methods Patients with untreated ES-SCLC were randomized to durvalumab plus EP or EP alone. We analyzed OS and safety in subgroups defined by age, sex, and planned platinum agent, and patient-reported outcomes (PROs) by age. Results Of 537 patients (durvalumab plus EP: n = 268; EP alone: n = 269), 80.6% versus 19.4% were aged <70 versus ≥70 years; 69.6% versus 30.4% were male versus female; and planned platinum was cisplatin versus carboplatin in 25.1% versus 74.9%. The OS HRs for durvalumab plus EP versus EP were 0.71 (95% CI, 0.58–0.88) versus 0.74 (95% CI, 0.49–1.11) for patients aged <70 versus ≥70 years; 0.76 (95% CI, 0.62–0.95) versus 0.60 (95% CI, 0.42–0.84) for males versus females; and 0.65 (95% CI, 0.45–0.94) versus 0.74 (95% CI, 0.60–0.91) for planned cisplatin versus carboplatin. With durvalumab plus EP, rates of grade 3/4 adverse events (AEs) were similar across subgroups; serious AEs were more frequent in patients aged ≥70 versus <70 years; and immune-mediated AEs were more common in females versus males. Adding durvalumab to EP had no detrimental effect on PROs in either age subgroup. Conclusions These findings support the use of durvalumab plus EP as first-line standard of care for ES-SCLC. Additional trials focused on elderly populations would be informative.