Durvalumab Consolidation Treatment Following Concurrent Chemoradiotherapy in Limited-Stage SCLC: ADRIATIC China Subgroup Analysis

Introduction: At the first interim analysis of the phase 3 ADRIATIC trial, durvalumab consolidation significantly improved overall survival (OS) and progression-free survival (PFS) compared with placebo in patients with limited-stage SCLC (LS-SCLC) without progression after concurrent chemoradiotherapy (cCRT). We report a prespecified subgroup analysis of patients enrolled in China. Methods: Patients with stage I to III LS-SCLC were randomized to durvalumab, durvalumab plus tremelimumab (arm remained blinded), or placebo for up to 24 months. The dual primary end points were OS and PFS by blinded independent central review for durvalumab versus placebo. Results: Of the global population, 95 of 530 patients (17.9%) were randomized in China; 49 of 264 versus 46 of 266 received durvalumab versus placebo. For prior cCRT, 69.4% versus 69.6% of the China subgroup received cisplatin-etoposide, and 53.1% versus 69.6% had once-daily radiotherapy; post-cCRT, 55.1% versus 67.4% received prophylactic cranial irradiation. The hazard ratio for OS (durvalumab versus placebo; median follow-up 35.5 mo) was 0.71 (95% confidence interval: 0.37-1.37). Median OS was not reached in either arm (36-mo OS: 63.7% versus 55.4%). The hazard ratio for PFS (median follow-up 27.7 mo) was 0.67 (95% confidence interval: 0.39-1.14); median PFS was 22.9 versus 14.3 months (24-mo PFS: 45.8% versus 37.6%). With durvalumab versus placebo, 16.3% versus 17.4% of patients had maximum grade 3 or 4 adverse events (AEs), 42.9% versus 21.7% had serious AEs, and 10.2% versus 13.0% discontinued treatment due to AEs; 55.1% versus 63.0% had pneumonitis/radiation pneumonitis (grade 3 or 4: 4.1% versus 4.3%). Conclusion: Consolidation durvalumab demonstrated a favorable benefit to risk profile in patients with LS-SCLC without progression after cCRT who were enrolled in China.