First-line tislelizumab plus chemotherapy for recurrent or metastatic nasopharyngeal cancer: three-year follow-up of RATIONALE-309

The phase 3 RATIONALE-309 trial, conducted at 42 sites across Asia, evaluated first-line tislelizumab versus placebo every three weeks, both with gemcitabine and cisplatin for 4 to 6 cycles, for recurrent or metastatic nasopharyngeal cancer (R/M NPC). Three-year follow-up results have now been published. Of 263 included participants, 206 (78.3%) were male, and the median age was 50 years (range 23-74). A total of 131 participants were randomized to the tislelizumab group and 132 to the placebo group, with crossover from placebo to tislelizumab permitted after progression. The median follow-up was 27.5 months (range 0.1-53.0). The median progression-free survival (PFS, primary endpoint) was 9.6 months in the tislelizumab group versus 7.4 months in the placebo group (HR 0.53; 95% CI 0.39-0.71) whereas the median overall survival (OS) was 45.3 months versus 31.8 months (0.73; 0.51-1.05). Rank-preserving structural failure time analysis and cross-over adjusted analysis showed greater OS benefit. Treatment-related adverse events occurred in all patients in the tislelizumab group and 99.2% of patients in the placebo group, with comparable grade 3 or higher adverse event rates. The authors conclude that these results support tislelizumab plus chemotherapy as a first-line treatment for R/M NPC.