Postoperative Chemotherapy Use and Outcomes From ADAURA: Osimertinib as Adjuvant Therapy for Resected EGFR-Mutated NSCLC

Introduction: Adjuvant chemotherapy is recommended in patients with resected stages II to IIIA (and select IB) NSCLC; however, recurrence rates are high. In the phase 3 ADAURA study (NCT02511106), osimertinib was found to have a clinically meaningful improvement in disease-free survival (DFS) in patients with resected stages IB to IIIA EGFR-mutated (EGFRm) NSCLC. Here, we report prespecified and exploratory analyses of adjuvant chemotherapy use and outcomes from ADAURA. Methods: Patients with resected stages IB to IIIA EGFRm NSCLC were randomized 1:1 to receive osimertinib or placebo for 3 years. Adjuvant chemotherapy before randomization was not mandatory, per physician and patient choice. DFS in the overall population (IB-IIIA), with and without adjuvant chemotherapy, was a prespecified analysis. Exploratory analyses included the following: adjuvant chemotherapy use by patient age, disease stage, and geographic location; DFS by adjuvant chemotherapy use and disease stage. Results: Overall, 410 of 682 patients (60%) received adjuvant chemotherapy (osimertinib, n = 203; placebo, n = 207) for a median duration of 4.0 cycles. Adjuvant chemotherapy use was more frequent in patients: aged less than 70 years (338 of 509; 66%) versus more than or equal to 70 years (72 of 173; 42%); with stages II to IIIA (352 of 466; 76%) versus stage IB (57 of 216; 26%); and enrolled in Asia (268 of 414; 65%) versus outside of Asia (142 of 268; 53%). A DFS benefit favoring osimertinib versus placebo was observed in patients with (DFS hazard ratio = 0.16, 95% confidence interval: 0.10-0.26) and without adjuvant chemotherapy (hazard ratio = 0.23, 95% confidence interval: 0.13-0.40), regardless of disease stage. Conclusions: These findings support adjuvant osimertinib as an effective treatment for patients with stages IB to IIIA EGFRm NSCLC after resection, with or without previous adjuvant chemotherapy. (C) 2021 International Association for the Study of Lung Cancer. Published by Elsevier Inc.