First-Line Selpercatinib or Chemotherapy and Pembrolizumab in RET Fusion-Positive NSCLC

Background Selpercatinib, a highly selective potent and brain-penetrant RET inhibitor, was shown to have efficacy in patients with advanced RET fusion-positive non-smallcell lung cancer (NSCLC) in a nonrandomized phase 1-2 study. Methods: In a randomized phase 3 trial, we evaluated the efficacy and safety of first-line selpercatinib as compared with control treatment that consisted of platinum-based chemotherapy with or without pembrolizumab at the investigator's discretion. The primary end point was progression-free survival assessed by blinded independent central review in both the intention-to-treat-pembrolizumab population (i.e., patients whose physicians had planned to treat them with pembrolizumab in the event that they were assigned to the control group) and the overall intention-totreat population. Crossover from the control group to the selpercatinib group was allowed if disease progression as assessed by blinded independent central review occurred during receipt of control treatment. Results In total, 212 patients underwent randomization in the intention-to-treat-pembrolizumab population. At the time of the preplanned interim efficacy analysis, median progression-free survival was 24.8 months (95% confidence interval [CI], 16.9 to not estimable) with selpercatinib and 11.2 months (95% CI, 8.8 to 16.8) with control treatment (hazard ratio for progression or death, 0.46; 95% CI, 0.31 to 0.70; P<0.001). The percentage of patients with an objective response was 84% (95% CI, 76 to 90) with selpercatinib and 65% (95% CI, 54 to 75) with control treatment. The cause-specific hazard ratio for the time to progression affecting the central nervous system was 0.28 (95% CI, 0.12 to 0.68). Efficacy results in the overall intention-to-treat population (261 patients) were similar to those in the intentionto- treat-pembrolizumab population. The adverse events that occurred with selpercatinib and control treatment were consistent with those previously reported. Conclusions: Treatment with selpercatinib led to significantly longer progression-free survival than platinum-based chemotherapy with or without pembrolizumab among patients with advanced RET fusion-positive NSCLC.