Sintilimab versus docetaxel as second-line treatment in advanced or metastatic squamous non-small-cell lung cancer: an open-label, randomized controlled phase 3 trial (ORIENT-3).

Background: Treatment options for Chinese patients with locally advanced or metastatic squamous-cell non-small-cell lung cancer (sqNSCLC) after failure of first-line chemotherapy are limited. This study (ORIENT-3) aimed to evaluate the efficacy and safety of sintilimab versus docetaxel as second-line treatment in patients with locally advanced or metastatic sqNSCLC.

Methods: ORIENT-3 was an open-label, multicenter, randomized controlled phase 3 trial that recruited patients with stage IIIB/IIIC/IV sqNSCLC after failure with first-line platinum-based chemotherapy. Patients were randomized in a 1:1 ratio to receive either 200 mg of sintilimab or 75 mg/m of docetaxel intravenously every 3 weeks, stratified by the Eastern Cooperative Oncology Group performance status. The primary endpoint was overall survival (OS) in the full analysis set (FAS). Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), duration of response (DoR) and safety.

Results: Between August 25, 2017, and November 7, 2018, 290 patients were randomized. For FAS, 10 patients from the docetaxel arm were excluded. The median OS was 11.79 (n = 145; 95% confidence interval [CI], 10.28-15.57) months with sintilimab versus 8.25 (n = 135; 95% CI, 6.47-9.82) months with docetaxel (hazard ratio [HR]: 0.74; 95% CI, 0.56-0.96; P = 0.025). Sintilimab treatment significantly prolonged PFS (median 4.30 vs. 2.79 months; HR: 0.52; 95% CI, 0.39-0.68; P < 0.001) and showed higher ORR (25.50% vs. 2.20%, P < 0.001) and DCR (65.50% vs. 37.80%, P < 0.001) than the docetaxel arm. The median DoR was 12.45 (95% CI, 4.86-25.33) months in the sintilimab arm and 4.14 (95% CI, 1.41-7.23) months in the docetaxel arm (P = 0.045). Treatment-related adverse events of grade ≥ 3 were reported in 26 (18.1%) patients in the sintilimab arm and 47 (36.2%) patients in the docetaxel arm. Exploratory biomarker analysis showed potential predictive values of expression levels of two transcription factors, including OVOL2 (HR: 0.35; P < 0.001) and CTCF (HR: 3.50; P < 0.001)，for sintilimab treatment.

Conclusions: Compared with docetaxel, sintilimab significantly improved the OS, PFS, and ORR of Chinese patients with previously treated locally advanced or metastatic sqNSCLC.