In a phase 3 trial in resected ALK-positive non-small-cell lung cancer (NSCLC), ensartinib markedly improved disease-free survival versus placebo. The study enrolled patients with completely resected stage IB to IIIB ALK-positive NSCLC following adjuvant chemotherapy. At 24 months, the proportion of patients with stage II to IIIB disease alive and disease-free was 86.4% in the ensartinib arm versus 53.5% with placebo (hazard ratio 0.20; 95% CI 0.11–0.38; p<0.001). Results were consistent in the overall population (87.3% vs 57.2%; HR 0.20; p<0.001), while overall survival data were immature. Higher-grade adverse events occurred more frequently with ensartinib (grade 3+ in 35.8% vs 18.2% with placebo), with rash as the most common grade 3+ event. The program is funded by Betta Pharmaceuticals and registered as NCT05341583.