REZILIENT2: Phase 2 study of zipalertinib in patients with advanced non-small cell lung cancer (NSCLC) with exon 20 insertions (ex20ins) and other uncommon epidermal growth factor receptor (EGFR) mutations.

TPS8670 Background: Patients with NSCLC harboring uncommon EGFR mutations, including ex20ins, have limited treatment options. Zipalertinib (CLN-081/TAS6417) is an oral tyrosine kinase inhibitor of EGFR with broad activity against EGFRmutations (including ex20ins) and increased selectivity for ex20ins versus wild-type EGFR. Zipalertinib has shown preclinical activity against a wide spectrum of EGFR ex20ins mutations and other uncommon EGFR mutations. In a phase 1/2a study (REZILIENT1), encouraging antitumor activity and an acceptable safety profile were observed in heavily pretreated patients with EGFRex20ins–mutant NSCLC, leading to ‘Breakthrough Therapy’ designation from the U.S. Food and Drug Administration. The aim of REZILIENT2 is to evaluate the efficacy and safety of zipalertinib in patients with NSCLC harboring EGFRex20ins and other uncommon single or compound EGFR mutations, including patients with brain metastases and leptomeningeal disease (LMD). Methods: In this global, phase 2b, open-label, multicohort study (NCT05967689), adult patients with locally advanced or metastatic NSCLC will be assigned to one of four cohorts depending on prior treatment and type of EGFR mutation: A) patients with EGFR ex20ins mutations who have progressed on or after first-line platinum-based chemotherapy and prior therapy targeting ex20ins (administered together or separately) for advanced disease; B) patients with EGFR ex20ins mutations who have not received prior treatment for advanced disease; C) patients with ex20ins or other uncommon single or compound EGFR mutations and active central nervous system metastases (including LMD) who may or may not have received prior treatment for advanced disease; and D) patients harboring other uncommon non-ex20ins single or compound EGFR mutations who have progressed on or after standard systemic therapy. Patients will receive zipalertinib at a starting dose of 100 mg orally twice daily, which will continue on a 21-day cycle until progression, unacceptable toxicity, or other discontinuation criteria are met. The primary endpoint is investigator-assessed objective response rate per Response Evaluation Criteria in Solid Tumours, version 1.1. Secondary endpoints include disease control rate, duration of response, progression-free survival, overall survival, intracranial efficacy per Response Assessment in Neuro-Oncology Brain Metastases (cohort C), safety and tolerability, and pharmacokinetics. Estimated enrollment is 40 patients per cohort (total 160), with potential expansion to ~100 patients per cohort if predefined threshold criteria of efficacy are met. Enrollment began in July 2023. Clinical trial information: NCT05967689 .