Tambotatug Pelitecan in Small-Cell Lung Cancer after Platinum-Based Therapy

BACKGROUND: Tambotatug pelitecan (known as Tam-Peli, a new antibody-drug conjugate that targets the immune-checkpoint molecule B7-H3) showed promising clinical efficacy in patients with relapsed extensive-stage small-cell lung cancer in early-phase trials. METHODS: In this phase 3, multicenter, open-label, randomized trial, we assigned eligible patients with small-cell lung cancer that had progressed after first-line platinum-based therapy in a 1:1 ratio to receive tambotatug pelitecan or topotecan. The primary end point was overall survival. The key secondary end points were progression-free survival and objective response as assessed by investigators. Here, we report the results from the prespecified interim analysis. RESULTS: A total of 451 patients underwent randomization: 225 were assigned to receive tambotatug pelitecan and 226 to receive topotecan. Overall survival was significantly longer with tambotatug pelitecan than with topotecan - a median of 13.3 months (95% confidence interval [CI], 12.1 to could not be estimated), as compared with 9.4 months (95% CI, 7.7 to 10.5); the stratified hazard ratio for death was 0.46 (95% CI, 0.35 to 0.62; P