Multicenter phase 3 trial of addition of toripalimab to first-line chemotherapy for extensive-stage small cell lung cancer

Patients with extensive-stage small cell lung cancer (ES-SCLC) have poor prognosis and unmet medical needs. The phase 3 EXTENTORCH trial, at 49 centers in China, evaluated addition of toripalimab (anti-PD-1) to first-line etoposide and platinum-based (EP) chemotherapy for ES-SCLC. Patients were randomized to receive toripalimab or placebo plus EP every three weeks for up to 4 to 6 cycles, followed by toripalimab or placebo maintenance for 2 years or untill progression or unacceptable toxicity. Median progression-free survival was 5.6 months in the toripalimab group and 5.4 months in the placebo group (HR 0.67; p<0.001) with PFS rate 18.1% versus 4.9% at 1 year. Median overall survival was 14.6 months in the toripalimab group and 13.3 months in the placebo group (HR 0.80; p=0.03), with OS rate 63.1% versus 54.9% at 1 year. The incidence of grade 3 or higher treatment-related adverse events was 89.6% in the toripalimab group and 89.4% in the placebo group. The authors conclude that addition of toripalimab to first-line EP chemotherapy for ES-SCLC was associated with significant improvement of PFS and OS (visual abstract).