Safety, Tolerability, Pharmacokinetics, and Preliminary Efficacy of YK-029A in Treatment-Naive Patients With Advanced NSCLC Harboring EGFR EXon 20 Insertion Mutations: A Phase 1 Trial

Introduction Treatment options for treatment-naive patients with advanced NSCLC harboring EGFR exon 20 insertion (ex20ins) mutations are limited. This study evaluated the safety, tolerability, and pharmacokinetics of YK-029A, a third-generation EGFR tyrosine kinase inhibitor, and the preliminary efficacy of YK-029A in treatment-naive patients with EGFR ex20ins mutation. Methods This multicenter, dose-escalation, and dose-expansion phase 1 clinical trial enrolled patients with NSCLC harboring EGFR mutations. During the dose-escalation phase, YK-029A was orally administered using the traditional 3+3 principle at 50, 100, 150, 200, and 250 mg/d. In the dose-expansion phase, treatment-naive patients with EGFR ex20ins mutations were enrolled and administered YK-029A 200 mg/d. The primary end point was safety and tolerability. Results The safety analysis included 108 patients. No dose-limiting toxicity was observed, and the maximum tolerated dose was not reached. The most common treatment-emergent adverse events were anemia (50.9%), diarrhea (49.1%), and rash (34.3%). There was minimal drug accumulation after multiple doses. A total of 28 treatment-naive patients with EGFR ex20ins mutations were enrolled in the dose-expansion and 26 were included in the efficacy analysis. According to the independent review committee evaluation, the objective response rate was 73.1% (95% confidence interval: 52.21%-88.43%), and the disease control rate was 92.3% (95% confidence interval: 74.87%-99.05%). Conclusions YK-029A was found to have manageable safety and be tolerable in patients with NSCLC harboring EGFR mutations and have promising antitumor activity in untreated patients with EGFR ex20ins mutations.