IBI310 plus sintilimab vs. placebo plus sintilimab in recurrent/metastatic cervical cancer: A double-blind, randomized controlled trial

Background: It remains unclear whether adding CTLA-4 blockade to PD-1/PD-L1 blockade improves clinical outcomes in cervical cancer (CC). Methods: In this randomized, double-blind, placebo-controlled, phase 2 study (ClinicalTrials.gov: NCT04590599), patients with recurrent/metastatic CC (R/M CC) who experienced disease progression after or during platinum-based chemotherapy were enrolled from 37 centers across China and randomly assigned (1:1), stratified by PD-L1 expression and prior treatment lines, to receive either IBI310 plus sintilimab or placebo plus sintilimab intravenously every 3 weeks for 12 weeks, followed by sintilimab alone. The primary endpoint was the objective response rate (ORR). Pivotal secondary endpoints included progression-free survival (PFS), overall survival (OS), and safety. Findings: 205 patients were randomized to receive IBI310-sintilimab (n = 103) or placebo-sintilimab (n = 102). The ORR difference between the IBI310-sintilimab arm (32.3%, 95% confidence interval [CI]: 23.3%–42.5%) and the placebo-sintilimab arm (23.5%, 95% CI: 15.5%–33.1%) was not significant (p = 0.17). IBI310-sintilimab and placebo-sintilimab exhibited median PFS values of 3.6 (95% CI: 2.7–6.3) and 4.2 months (95% CI: 2.8–6.2), respectively (hazard ratio [HR] = 0.91, 95% CI: 0.65–1.27; p = 0.58). The median OSs were 13.9 months (95% CI: 11.5–25.6) in the IBI310-sintilimab arm and 17.2 months (95% CI: 13.7–25.9) in the placebo-sintilimab arm (HR = 1.12, 95% CI: 0.79–1.58; p = 0.54). Adding IBI310 to sintilimab increased the incidence of grade ≥3 treatment-related adverse events (55% versus 19%). Conclusions: Compared to single-agent PD-1/PD-L1 blockade, dual blockade of CTLA-4 and PD-1/PD-L1 did not significantly improve clinical outcomes in R/M CC. Funding: This work was funded by Innovent Biologics (Suzhou).