S1059 Efficacy and Safety of Tislelizumab in Esophageal Squamous Cell Carcinoma: A Proportionality Meta-Analysis

Introduction: Tislelizumab, a humanized anti–programmed cell death protein 1 monoclonal antibody, has shown promising antitumor activity in esophageal squamous cell carcinoma (ESCC), a malignancy with poor prognosis and limited therapeutic options. While individual studies report variable outcomes, a comprehensive meta-analysis quantifying its efficacy and safety is lacking. We aim to evaluate the pooled efficacy and safety outcomes of tislelizumab in ESCC using a proportionality meta-analysis. Methods: A systematic literature search identified eligible prospective studies reporting survival and response outcomes in ESCC patients treated with tislelizumab (alone or in combination). Data were extracted for 1-year and 2-year overall survival (OS), 1-year and 2-year progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), pathological complete response (pCR), major pathological response (MPR), partial response rate (PRR), and adverse events (AEs), including grade ≥3 AEs. A random-effects proportional meta-analysis was performed using the DerSimonian-Laird method. Between-study heterogeneity was assessed by I² statistics. Results: Nine studies involving 795 patients were included. The pooled 1-year OS was 75% (95% confidence interval [CI] 58-89%), and 2-year OS was 56% (95% CI 36-74%). The 1-year PFS rate was 96% (95% CI 93-99%) and 2-year PFS was 48% (95% CI 26-71%). The objective response rate (ORR) reached 81% (95% CI 51-99%), with a disease control rate (DCR) of 47% (95% CI 34-59%). Pathological complete response (pCR) and major pathological response were both estimated at 53%, while the partial response rate was 36%. All-grade adverse events occurred in 23% of patients, and grade ≥3 adverse events in 58%. Overall, tislelizumab showed promising efficacy and manageable safety in ESCC. Conclusion: Tislelizumab demonstrates encouraging efficacy in ESCC with high 1-year PFS and OS rates, notable response rates (ORR, DCR, pCR), and manageable safety profile. The observed heterogeneity across studies underscores the need for further prospective randomized trials to optimize patient selection and combination strategies.