Multicenter randomized phase 2 trial of toripalimab consolidation after chemoradiotherapy in limited-stage small cell lung cancer

Immune checkpoint inhibitors (ICIs) plus chemotherapy has demonstrated survival benefit in extensive-stage small cell lung cancer. A multicenter randomized phase 2 trial in China evaluated toripalimab consolidation versus observation after concurrent chemoradiotherapy (CCRT) in patients with limited-stage small cell lung cancer (LS-SCLC). A total of 98 LS-SCLC patients who had completed CCRT were randomized 1:1 to toripalimab 240 mg every 3 weeks for up to 6 months (n=49) or observation (n=49). Primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival (OS), objective response rate (ORR), and toxicities. Median PFS and OS were not reached in the toripalimab group and were 14.1 months and 30.3 months, respectively, in the observation group (PFS: HR 0.55; 95% CI 0.31-0.96; OS: HR0.39; 95% CI 0.19-0.80). ORR was 60.9% in the toripalimab group and 37.5% in the observation group. Treatment-related toxicities were generally mild; adverse events led to discontinuation of the study drug in 12.5% of patients in the toripalimab group. No grade 4 or 5 adverse events occurred in either group. The authors conclude that consolidative toripalimab showed promising signals of improved PFS and OS with a manageable safety profile in patients with LS-SCLC after completion of CCRT.