Osimertinib in NSCLC: Real-World Data From New Zealand

Abstract

IntroductionEGFR tyrosine kinase inhibitors (TKIs) are more effective than chemotherapy in patients with EGFR-mutant NSCLC. Disease progression on EGFR TKI therapy occurs most often owing to acquired resistance from the gain of an EGFR T790M mutation. Osimertinib, a third-generation EGFR TKI, significantly improves outcomes in patients with EGFR T790M mutation–positive NSCLC compared with platinum–pemetrexed chemotherapy. We retrospectively reviewed clinical outcomes for patients receiving osimertinib through a compassionate access program in New Zealand. MethodsPatients with a biopsy-proven or plasma-circulating tumor-DNA–proven EGFR T790M mutation received osimertinib. Data on patient and tumor characteristics, treatments, and outcomes were collected retrospectively. Survival outcomes were calculated from the time of osimertinib commencement. ResultsA total of 39 patients were enrolled, and data from 37 patients were analyzed. EGFR T790M status was found from plasma samples in six of 37 (16%) patients. A total of 27 of 37 patients (73%) used osimertinib as a second-line treatment. At the time of data analysis, median follow-up was 18.8 months (range 1.5–29). Overall response rate was 70% (95% confidence interval [CI]: 53–84) (26 of 37). Progression-free survival (PFS) at 12 months was 62% (95% CI: 44.8–77.5), and median PFS was 14.6 months (95% CI: 12.4–16.8). Median overall survival was not reached. Osimertinib was well tolerated, with grade 1 gastrointestinal and skin toxicity as the most common adverse effects. Three patients required dose adjustments or cessation owing to toxicity. ConclusionOsimertinib is an effective treatment for New Zealanders with EGFR T790M mutated NSCLC who have progressed after first or subsequent lines of therapy.