Final overall survival and biomarker analyses of CHOICE-01: A double-blind randomized phase 3 study of toripalimab versus placebo in combination chemotherapy for advanced NSCLC without EGFR/ALK mutations

9003 Background: Toripalimab in combination with chemotherapy showed significant improvement over chemotherapy alone in progression-free survival (PFS) and overall survival (OS) as first-line treatment of advanced NSCLC at the final PFS analysis of the CHOICE-01 study (NCT03856411). Here we report the final OS analysis. Methods: Patients (n=465) with treatment-naïve, advanced NSCLC without EGFR/ALK mutations were randomized 2:1 to receive toripalimab 240 mg (n=309) or placebo (n=156) in combination with chemotherapy for 4-6 cycles, followed by maintenance toripalimab or placebo plus standard care until disease progression, intolerable toxicity, or completion of 2 years of treatment. Patients from the placebo arm were actively crossed-over to receive toripalimab upon disease progression. The primary endpoint was PFS. The secondary endpoints included OS and safety. Results: By the cutoff date of August 31, 2022, when 283 events triggered the final OS analysis, the median survival follow up was 19.4 months. A significant improvement in OS was observed for the toripalimab arm over the placebo arm: HR=0.73 (95% CI: 0.57-0.93), two-sided p=0.0108, median OS 23.8 vs 17.0 months. A consistent effect on OS, favoring the toripalimab arm, was observed all PD-L1 expression subgroups. The OS benefit is greater in non-squamous NSCLC, HR=0.50 (95% CI: 0.36-0.70), median OS 27.8 vs 15.9 months, whereas no significant difference was found in the squamous subgroup (mOS 19.6 vs 18.1 months) despite a significant PFS improvement. The squamous subgroup had a high 70% crossover rate. No new safety signal was identified since the interim report. The incidence of Grade ≥3 adverse events (AEs) (78.9% vs 82.1%) was similar between the two arms. AEs leading to discontinuation of toripalimab/placebo (14.3% vs 3.2%), fatal AEs (5.5% vs 2.6%), and immune-related (irAEs) (50.6% vs. 21.2%) were more frequent in the toripalimab arm. Whole exome sequencing results indicated patients with mutations in the FAK-PI3K-Akt pathway achieved significantly better OS from the toripalimab arm. Conclusions: The addition of toripalimab to chemotherapy in patients with advanced NSCLC provided significant OS benefit than chemotherapy alone with a manageable safety profile. These results support the use of toripalimab with chemotherapy as 1 st line therapy for advanced NSCLC patients without EGFR/ALK mutations. Clinical trial information: NCT03856411 .