Adjuvant icotinib versus observation in patients with completely resected, EGFR-mutated, stage IB non–small cell lung cancer (GASTO1003, CORIN): A randomized phase II trial.

8519 Background: The role of adjuvant therapy in patients with completely resected stage IB non-small-cell lung cancer (NSCLC) remains to be determined. Icotinib is standard-of-care therapy for patients with advanced NSCLC harboring epidermal growth factor receptor (EGFR) mutation. This phase II study investigated whether adjuvant therapy with icotinib improves the clinical outcome compared with observation in patients with EGFR mutation-positive resected stage IB NSCLC. Methods: This phase II, open-label, randomized study (GASTO1003, CORIN) was conducted at Sun Yat-sen University Cancer Center. From May 2013 to December 2020, patients with completely resected, EGFR mutation-positive, stage IB (7th TNM staging for NSCLC) NSCLC without adjuvant chemotherapy according to physician and patient choices were enrolled. The patients were assigned in a 1:1 ratio to receive adjuvant therapy with icotinib (125mg, three times daily) for 12 months or to undergo observation. Therapy continued until disease progression or intolerable toxicity. The primary endpoint was disease-free survival (DFS). Secondary endpoints included overall survival (OS) and toxicity. Survival endpoints were assessed in the intention-to-treat population. Results: Three patients withdrew consent and were excluded. A total of 128 patients were enrolled and randomized, with 63 patients in the icotinib group and 65 patients in the observation group. Baseline characteristics were well balanced between the groups. The median duration of follow-up was 34.9 months. A total of 13 recurrence events occurred, including 2 in the icotinib arm and 11 in the observation arm. DFS was significantly longer among those in the icotinib arm than among those in the observation arm (hazard ratio: 0.20, 95% confidence interval, 0.04-0.89; P = 0.018). The 3-year DFS for the icotinib and observation arms were 95.3% and 86.7%, respectively. The OS data were immature with 3 deaths in the observation arm. The safety profile was consistent with the known safety profile of icotinib. Icotinib was well tolerated with no unexpected adverse events. No treatment-related death occurred. Conclusions: Adjuvant icotinib shows prolonged DFS and acceptable toxicity in patients with completely resected EGFR-mutated stage IB NSCLC. Ajuvant icotinib provides a treatment option for these patients. Clinical trial information: NCT02264210.