Neoadjuvant and Adjuvant Osimertinib in Stage IA to IIIA, EGFR-Mutant NSCLC (NORA)

Abstract

Introduction: Treatment with adjuvant osimertinib for three years is the standard-of-care for resected stage IB to IIIA NSCLC harboring EGFR mutations. The role of neoadjuvant osimertinib in the perioperative setting is yet to be elucidated in the NeoADAURA study (NCT04351555).

Methods: This is a single-center, pilot study of patients with clinical stage IA to IIIA NSCLC (American Joint Committee on Cancer eighth edition) harboring an activating EGFR mutation (Exon 19 deletion, L858R) (NCT04816838). Patients were treated with two 28-day cycles of neoadjuvant osimertinib followed by surgical resection and three years of adjuvant osimertinib. The primary endpoint was the objective response rate after two cycles of neoadjuvant treatment. Secondary endpoints included the pathologic complete response rate and major pathologic response rate. Exploratory objectives included the correlation of longitudinal circulating tumor DNA testing (Signatera) and response to neoadjuvant osimertinib.

Results: A total of 25 patients were enrolled and treated with neoadjuvant osimertinib, and all patients received surgical resection with R0 resection. The objective response rate was 44% (n = 11) all of which were partial responses. Fourteen patients (56%) reported stable disease after neoadjuvant osimertinib. The major pathologic response and pathologic complete response rates were 24% (n = 6) and 0%, respectively. None of the patients received adjuvant chemotherapy. The median disease-free survival was not reached at a median follow-up of 31 months (range: 13.8-38.6 mo). Six patients (30%) were circulating tumor DNA-positive at baseline and achieved clearance after 1 cycle of neoadjuvant osimertinib. There were no grade 3 adverse events during neoadjuvant treatment.

Conclusions: Two cycles of neoadjuvant osimertinib did not meet its primary endpoint of ORR. Neoadjuvant osimertinib is a feasible approach with a manageable safety profile in resectable EGFR-mutant NSCLC.