Observational Study of Treatment Patterns in Patients with Epidermal Growth Factor Receptor (EGFR) Mutation-Positive Non-Small Cell Lung Cancer After First-Line EGFR-Tyrosine Kinase Inhibitors.

Introduction: Epidermal growth factor receptor (EGFR) mutations are observed in approximately 15% of patients with non-small cell lung cancer (NSCLC) in the USA. Little is known about treatment patterns in EGFR mutation-positive NSCLC following progression on or after first-line (1L) treatment with first- or second-generation EGFR tyrosine kinase inhibitors (EGFR-TKIs). Osimertinib, a third-generation EGFR-TKI, is a treatment option for patients with EGFR T790M-positive NSCLC following progression on 1L EGFR-TKIs. This study analyzed real-world treatment sequencing of EGFR-TKIs, EGFR T790M testing rates, and disposition of patients with EGFR mutations after 1L EGFR-TKI post-FDA approval of osimertinib in patients with EGFR mutation-positive NSCLC.

Methods: Adult patients with stage IV NSCLC and documented EGFR mutation-positive status were identified between December 1, 2015 and May 31, 2017 from the US Oncology Network iKnowMed™ electronic health record (EHR). Data were abstracted from the EHR database and supplemented by chart review.

Results: Of 308 patients, 302 (98%) received an EGFR-TKI overall, and 246 patients (80%) received a 1L EGFR-TKI. The most common 1L EGFR-TKI was erlotinib (66%); the remaining 1L regimens were predominantly combination chemotherapies with or without an EGFR-TKI. Only 80 patients (26%) received any 2L therapy. The most common EGFR-TKIs used as 2L monotherapy in patients who received 1L EGFR-TKI were afatinib and osimertinib (n = 7 for both). Among all patients treated with 1L EGFR-TKI (n = 246), 47 (19%) were tested for EGFR T790M [16 patients (34%) were positive], 48 (20%) remained on 1L EGFR-TKI, 29 (12%) received subsequent therapy, 38 (15%) had died on or after their 1L EGFR-TKI therapy, and 131 (53%) stopped their EGFR-TKI with no recorded evidence of having received subsequent therapy at follow-up end.

Conclusion: Following 1L EGFR-TKI treatment, 19% of patients were tested for EGFR T790M, and most (69%) had no record of receiving any subsequent therapy.