Zipalertinib in Patients With Epidermal Growth Factor Receptor Exon 20 Insertion-Positive Non-Small Cell Lung Cancer Previously Treated With Platinum-Based Chemotherapy With or Without Amivantamab.

Objective: To evaluate the safety and efficacy of zipalertinib, an irreversible epidermal growth factor receptor (EGFR) inhibitor, in pretreated patients with non-small cell lung cancer (NSCLC) harboring EGFR exon 20 insertion (ex20ins) mutations.

Methods: REZILIENT1 (ClinicalTrials.gov identifier: NCT04036682) is a phase I/II open-label trial enrolling patients with locally advanced or metastatic EGFR ex20ins-mutant NSCLC previously treated with platinum-based chemotherapy with/without ex20ins-targeted therapies. Asymptomatic, treated and untreated stable CNS metastases are permitted. We report data from patients treated with zipalertinib 100 mg twice daily. The primary end points are objective response rate (ORR) and duration of response (DOR) by independent central review.

Results: At data cutoff (December 10, 2024), 244 patients had received treatment with zipalertinib 100 mg twice daily. The primary efficacy population (8 months' follow-up) comprised patients who had received prior platinum-based chemotherapy without ex20ins-targeted therapy (125 patients), with amivantamab only (30 patients), or with amivantamab and other ex20ins-targeted therapy (21 patients). The confirmed ORR was 35.2% (95% CI, 28.2 to 42.8); median DOR was 8.8 months (95% CI, 8.3 to 12.7). Among patients who received prior platinum-based chemotherapy without ex20ins-targeted therapy, amivantamab only, or amivantamab and other ex20ins-targeted therapy, the confirmed ORR was 40%, 30%, and 14.3%, and median DOR was 8.8, 14.7, and 4.2 months, respectively. Among 68 patients with CNS metastases, the ORR was 30.9%. The most common grade ≥3 treatment-related adverse events were anemia (7%), pneumonitis and rash (2.5% each), and diarrhea, ALT increased, and platelet count decreased (2% each).

Conclusions: Zipalertinib demonstrated clinically meaningful efficacy with a manageable safety profile in patients with EGFR ex20ins-mutant NSCLC who received prior platinum-based chemotherapy with or without amivantamab.