Aims: Selpercatinib, a selective, potent and brain-penetrant RET inhibitor, is approved for RET+ advanced/metastatic non-small cell lung cancer (NSCLC). We report the efficacy and safety of selpercatinib vs placebo in patients with stage IB-IIIA RET+ NSCLC.
Methods: LIBRETTO-432 is a placebo-controlled, double-blind, phase 3 randomized (1:1) trial of selpercatinib 160mg BID vs placebo for ≤3 years in patients with stage IB-IIIA RET+ NSCLC after definitive locoregional treatment. Primary endpoint was investigator-assessed EFS in stage II-IIIA patients.
Results: In total, 151 patients were randomized (selpercatinib n=75; placebo n=76). Median follow-up was 24 months for selpercatinib and 27 months for placebo. At the preplanned efficacy analysis, selpercatinib demonstrated significantly improved EFS in patients with stage II-IIIA disease (n=109), HR 0.172 (95%CI:0.058-0.509; p=0.0003). The median EFS was not reached for selpercatinib vs 31.8 months for placebo (4 vs 19 EFS events, respectively). EFS by BICR, HR=0.125 (95%CI:0.028-0.552), was consistent with investigator-assessed EFS. The 2-year EFS rate was 91.5% for selpercatinib vs 61.1% for placebo. In the overall population (n=151), error-controlled EFS HR=0.165 (95%CI:0.056-0.485; p=0.0002), and median EFS was not reached on either treatment arm. Most common AEs were increased ALT/AST. Only 3 deaths were observed, all in the placebo arm. No patients died during assigned study treatment.
Conclusions: Selpercatinib achieved a statistically significant and clinically meaningful improvement in EFS vs placebo in patients with early-stage RET+ NSCLC. These data add to the body of evidence for targeted therapy in the adjuvant NSCLC setting and underscore the importance of comprehensive genomic testing at diagnosis of NSCLC.