First-line durvalumab plus platinum-etoposide in extensive-stage small-cell lung cancer: CASPIAN Japan subgroup analysis

Abstract

Abstract Background In the phase 3 CASPIAN study (NCT03043872), first-line durvalumab plus etoposide and cisplatin or carboplatin (EP) significantly improved OS versus EP alone in patients with extensive-stage (ES)-SCLC (HR 0.73 [95% CI 0.59–0.91; p = 0.0047]). Here we report results for a preplanned subgroup analysis of patients recruited in Japan. Methods Treatment-naïve patients with ES-SCLC received either 4 cycles of durvalumab 1500 mg plus EP q3w followed by maintenance durvalumab 1500 mg q4w until disease progression or up to 6 cycles of EP q3w. The primary endpoint was OS. Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), safety, and tolerability. Results In the Japan subgroup, 18 patients were randomized to durvalumab plus EP and 16 patients to EP. At the interim analysis with a median follow-up of 12.5 months in the subgroup, OS numerically favored durvalumab plus EP versus EP (HR 0.77 [95% CI 0.26‒2.26]; median not reached vs 15.2 months). PFS was similar for durvalumab plus EP versus EP (HR 0.90 [95% CI 0.43‒1.89]). Confirmed ORR was 89% with durvalumab plus EP versus 69% with EP. Adverse events (AEs) of CTCAE grade 3 or 4 were reported in 78% versus 94% of patients in the durvalumab plus EP versus EP arms. There were no AEs leading to treatment discontinuation or death in the Japan subgroup. Conclusion First-line durvalumab plus EP was effective and well tolerated in Japanese patients with ES-SCLC. Despite the small size of the Japan subgroup, results were generally consistent with the global study population.