Clinical efficacy and safety of tiragolumab plus atezolizumab across solid tumors: A meta-analysis of randomized controlled trials.

Abstract

e14574 Background: Tiragolumab, a first-in-class anti-TIGIT antibody, has emerged as a novel immunotherapeutic strategy in combination with immune checkpoint inhibitors. While its combination with atezolizumab has been evaluated across multiple solid tumors; however, the overall clinical benefit remains uncertain. This systematic review aims to summarize the current clinical evidence evaluating the efficacy and safety of tiragolumab plus atezolizumab in patients with solid tumors. Methods: A systematic search was conducted in PubMed, Scopus, and Cochrane databases to identify relevant randomized controlled trials (RCTs) published up to 15 January 2026. Outcomes were pooled using an inverse-variance random-effects meta-analysis. Relative risks (RRs) and hazard ratios (HRs) were used as effect measures (PROSPERO CRD420261285773). Results: Five RCTs comprising 1466 patients were analyzed. Compared to atezolizumab-based chemoimmunotherapy, tiragolumab/atezolizumab improved objective response rate (ORR: RR 1.49 [95%CI 1.33–1.68]), although it resulted in similar disease control rate (1.29 [0.92-1.81]), overall survival (OS: HR 0.75 [95%CI0.51–1.12]) and progression-free survival (PFS: 0.78 [0.52-1.16]). There were no significant differences in grade ≥3 adverse events (AEs) (RR0.89 [95%CI0.66–1.21]) or grade 5 AEs (0.79 [0.19–3.22]). In a subgroup of esophageal cancer patients, tiragolumab/atezolizumab resulted in better OS (HR 0.69 [95%CI 0.55-0.86]), PFS (HR 0.56 [95%CI 0.45-0.68]), and ORR (RR1.36 [95%CI1.15-1.61]), with similar rates of grade ≥3 AE (RR 1.12 [95%CI 0.98-1.29]) compared to chemotherapy alone. Conclusions: The addition of tiragolumab to atezolizumab-based chemoimmunotherapy regimen provides a modest improvement in ORR with limited survival benefit. Nonetheless, this regimen appears superior to chemotherapy alone. Interpretation of tumor-specific efficacy is constrained by the limited availability of data, and further high-quality, tumor-specific RCTs are needed to substantiate our findings. Meta-analysis on the efficacy and safety of tiragolumab/atezolizumab versus atezolizumab-based chemoimmunotherapy regimen in patients with solid tumor. Outcome No. of reports No. of patients Estimate 95%CI I2 P heterogeneity Efficacy OS 4 833 HR 0.75 0.51-1.12 71% 0.017 PFS 4 833 HR 0.78 0.52-1.16 71% 0.212 ORR 5 910 RR 1.49 1.33-1.66 7% 0.369 DCR 3 356 RR 1.29 0.92-1.81 47% 0.150 Safety Grade ≥1 AE 5 976 RR 1.03 0.98-1.08 40% 0.152 Grade ≥3 AE 5 976 RR 0.89 0.66-1.21 67% 0.016 Grade 5 AE 5 976 RR 0.79 0.19-3.22 34% 0.221 Abbreviation: AE, adverse event; DCR, disease control rate; HR, hazard ratio; ORR, objective response rate; OS, overall survival; PFS, progression-free survival; RR, relative risk.