Durvalumab ± Tremelimumab + Platinum-Etoposide in Extensive-Stage Small Cell Lung Cancer (CASPIAN): Outcomes by PD-L1 Expression and Tissue Tumor Mutational Burden

PURPOSE: In the CASPIAN trial, first-line durvalumab plus platinum-etoposide (EP) significantly improved overall survival (OS) versus EP alone in extensive-stage small cell lung cancer (ES-SCLC). We report exploratory analyses of CASPIAN outcomes by programmed cell death ligand-1 (PD-L1) expression and tissue tumor mutational burden (tTMB). EXPERIMENTAL DESIGN: Patients were randomized (1:1:1) to durvalumab (1,500 mg) plus EP, durvalumab plus tremelimumab (75 mg) plus EP, or EP alone. Treatment effects in PD-L1 and tTMB subgroups were estimated using an unstratified Cox proportional hazards model. RESULTS: The PD-L1 and tTMB biomarker-evaluable populations (BEP) comprised 54.4% (438/805) and 35.2% (283/805) of the intention-to-treat population, respectively. PD-L1 prevalence was low: 5.7%, 25.8%, and 28.3% had PD-L1 expression on

• Paz-Ares, L.
• Garassino, M. C.
• Chen, Y.
• Reinmuth, N.
• Hotta, K.
• Poltoratskiy, A.
• Trukhin, D.
• Hochmair, M. J.
• Özgüro
• Ji, J. H.
• Statsenko, G.
• Conev, N.
• Bondarenko, I.
• Havel, L.
• Losonczy, G.
• Xie, M.
• Lai, Z.
• Godin-Heymann, N.
• Mann, H.
• Jiang, H.
• Shrestha, Y.
• Goldman, J. W.