In a Chinese phase II trial (EC-CRT-002) reported in the Journal of Clinical Oncology, Chen et al found that the addition of the anti–PD-1 monoclonal antibody tislelizumab without maintenance cycles to induction chemotherapy and concurrent chemoradiotherapy significantly improved progression-free survival vs historical control in patients with locally advanced esophageal squamous cell carcinoma.
Study Details
In the open-label multicenter trial, 114 patients with newly diagnosed, unresectable stage II to IVB esophageal squamous cell carcinoma were randomly assigned between October 2022 and October 2024 to receive 2 cycles of paclitaxel/cisplatin induction chemotherapy followed by concurrent chemoradiotherapy in combination with tislelizumab for 16 cycles consisting of 2 induction, 2 concurrent, and 12 maintenance cycles (n = 57) or 4 cycles of tislelizumab consisting of 2 induction and 2 concurrent cycles (n = 57). The primary endpoint was progression-free survival vs historical control (1-year progression-free survival of 56% following definitive chemoradiotherapy).
Key Findings
After a median follow-up of 22.7 months (interquartile range = 16.2–28.2 months), the group with no maintenance tislelizumab had better 1-year progression-free survival vs historical control (71.9%, 95% confidence interval [CI] = 61.1%–84.6%, vs 56.4%, 95% CI = 44.7%–71.1%; hazard ratio [HR] = 0.54, 95% CI = 0.32–0.94), whereas no benefit was observed in the group with tislelizumab maintenance (52.6%, 95% CI = 41.4%–67.3%; HR = 1.06, 95% CI = 0.67–1.68).
Overall survival was also significantly better in the no-maintenance tislelizumab group vs historical control (HR = 0.42, 95% CI = 0.22–0.82), but not in the maintenance tislelizumab group vs historical control (HR = 0.82, 95% CI = 0.48–1.40).
Grade ≥ 3 adverse events occurred in 86.0% of the maintenance group vs 80.7% of the no-maintenance group, most commonly lymphopenia (77.2% and 73.7%) in both.
The investigators concluded: “The addition of tislelizumab to induction chemotherapy and concurrent [chemoradiotherapy] without maintenance immunotherapy demonstrated superior efficacy and manageable toxicity in locally advanced [esophageal squamous cell carcinoma].”
Mian Xi, MD, of State Key Laboratory of Oncology in South China, Collaborative Innovation Centre for Cancer Medicine, Guangdong Esophageal Cancer Institute, Guangzhou, China, is the corresponding author for the Journal of Clinical Oncology article.
DISCLOSURE: The study was funded by the National Natural Science Foundation of China. For full disclosures of the study authors, visit ascopubs.org.
