Multinational phase 3 trial of first-line tislelizumab plus chemotherapy for advanced ESCC: minimum 3-year follow-up from RATIONALE-306

In the multinational phase 3 RATIONALE-306 trial, 649 patients with previously untreated unresectable advanced or metastatic esophageal squamous cell carcinoma (ESCC) were randomized 1:1 to tislelizumab plus investigator-chosen chemotherapy or placebo plus chemotherapy. Primary analysis of the trial showed that after minimum follow-up of 15 months, overall survival (OS) was significantly improved in the tislelizumab group compared with the placebo group. Results after minimum follow-up of 3 years have now been published. Tislelizumab plus chemotherapy improved median OS versus placebo plus chemotherapy 17.2 versus 10.6 months; HR 0.70; 95% CI 0.59-0.80). At 3 years, 15.0% of patients receiving tislelizumab plus chemotherapy had not progressed, versus 2.9 % of those receiving placebo plus chemotherapy. No new safety signals were identified. Median time to deterioration of physical functioning had not been reached with tislelizumab plus chemotherapy and was 18.8 months with placebo plus chemotherapy. The authors conclude that with longer follow-up, tislelizumab plus chemotherapy demonstrated long-lasting efficacy, tolerable safety, and favorable patient-reported outcomes among patients with previously untreated unresectable advanced or metastatic ESCC.