Perioperative toripalimab + platinum-doublet chemotherapy vs chemotherapy in resectable stage II/III non-small cell lung cancer (NSCLC): Interim event-free survival (EFS) analysis of the phase III Neotorch study.

425126 Background: Adjuvant and neoadjuvant immunotherapy have been approved by US FDA to treat early-stage NSCLC. However, the optimal neoadjuvant and adjuvant treatment, including duration of treatment, are unknown. We present the interim results of a randomized, double-blind, placebo-controlled, phase III trial to evaluate the efficacy and safety of perioperative toripalimab plus chemotherapy followed by toripalimab maintenance vs chemotherapy in resectable stage III NSCLC. Methods: Patients with stage II/III resectable NSCLC, without EGFR/ALK alterations for non-squamous NSCLC, were randomly assigned 1:1 to receive 240 mg toripalimab or placebo combined with chemotherapy Q3W for 3 cycles before surgery and one cycle after surgery, followed by toripalimab or placebo monotherapy Q3W for 13 cycles. Stratification variables for randomization included disease stage, histopathologic subtype, PD-L1 expression and surgical procedure. Primary endpoints were EFS by investigator and major pathological response (MPR) rate by a blinded independent pathologic review (BIPR) in the stage III and the ITT populations. Secondary endpoints included overall survival (OS), pathologic complete response (pCR) rate, EFS by independent review committee (IRC), and safety. A planned interim analysis was performed on the primary endpoint of EFS in the stage III subjects. Results: A total of 404 patients with stage III NSCLC were randomly assigned to toripalimab (n=202) or placebo (n=202). By the data cutoff date (November 30, 2022), the median follow-up was 18.3 months. Baseline characteristics were well balanced between the two arms. EFS was significantly improved in the toripalimab arm, HR=0.40, 95% CI (0.277-0.565), P<0.0001, and crossed the pre-specified efficacy boundary. The median EFS was not reached in the toripalimab arm and 15.1 months in the placebo arm. A consistent effect on EFS, favoring toripalimab, was observed in all subgroups. The MPR and pCR rates per BIPR were also higher in the toripalimab arm, 48.5% vs 8.4% and 24.8% vs 1.0%, respectively. The OS results showed a trend favoring toripalimab. The incidence of Grade ≥3 adverse events (AEs) (63.4% vs 54.0%), fatal AEs related to toripalimab/placebo (0.5% vs 0%) and AEs leading to discontinuation of toripalimab/placebo (9.4% vs 7.4%) were comparable between the two arms. However, the incidence of immune-related AEs (42.1% vs 22.8%) was more frequent in the toripalimab arm. Conclusions: The addition of toripalimab to perioperative chemotherapy showed statistically significant improvements in EFS for patients with stage III NSCLC with a manageable safety profile. Patients will be followed for overall survival. Clinical trial information: NCT04158440 .