Long-term safety and survival with gefitinib in select patients with advanced non-small cell lung cancer: Results from the US IRESSA Clinical Access Program (ICAP).

Background: This is the first report of long-term (>10 years) safety, tolerability, and survival data on patients with non-small cell lung cancer (NSCLC) who received treatment with gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor.

Methods: Patients with advanced NSCLC (N = 191) who entered the IRESSA Clinical Access Program (ICAP) (June 2011 to January 2013) and had previously obtained a clinical benefit from gefitinib therapy (including patients who had received gefitinib since 2001) were analyzed for adverse events (AEs). A subset of patients (n = 79) underwent retrospective chart review to capture demographic, safety, and survival data.

Results: Seventy-five of 191 patients (39%) remained on long-term gefitinib therapy as of September 2016. Overall, serious AEs (SAEs) were reported in 64 patients (34%), the majority of which were attributed to underlying disease or comorbidities; only 3 patients (1.6%) had SAEs that were considered as possibly gefitinib-related. In the retrospective chart review cohort, 70% of patients were women; 58% were former smokers, and 30% were never-smokers; 56% were diagnosed with adenocarcinoma, and 13% were diagnosed with squamous carcinoma. Although EGFR mutational status was tested in only 17 patients (22%), it was assumed that most tumors were EGFR-mutation-positive. The median duration of gefitinib therapy was 11.1 years (7.8 years before and 3.5 years during ICAP), with 10-year and 15-year survival rates of 86% and 59%, respectively, from the initiation of therapy.

Conclusions: A subset of long-term NSCLC survivors who were receiving gefitinib had an excellent long-term safety profile. Although it is assumed that most of these patients' tumors harbor EGFR mutations, molecular studies of available tumor specimens are planned to uncover the features that predict long-term survival. Cancer 2018;124:2407-14. © 2018 American Cancer Society.