Length of Therapy with Osimertinib as First-Line Treatment vs Standard EGFR-TKIs Plus Second Line Osimertinib Treatment in Treating Non-Small Cell Lung Cancer Patients with an EGFR Mutation

Abstract

Specific Aims: Primary aim is to determine if patients initiated with osimertinib had a longer duration of treatment compared to the sum of treatment duration of standard Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors (EGFR-TKIs) such as erlotinib, afatinib, and gefitinib plus the use of osimertinib after failure with a standard EGFR-TKI in patients with EGFR-mutated Non-Small Cell Lung Cancer (NSCLC) at a specialty pharmacy. Our secondary aim is to determine if the frequency and severity of adverse events was lower in patients initiated on osimertinib compared to patients who used a standard EGFR-TKI, failed therapy and then used osimertinib. Methods: There were 498 patients who met inclusion criteria and were split into two groups based on their therapy, if they were taking osimertinib as their first-line therapy for NSCLC or taking it after failing a standard EGFR-TKI (EGFR-TKI + osimertinib) from Avella Specialty Pharmacy. Patients in the EGFR-TKI + osimertinib group's duration of therapy was calculated by adding the duration of therapy of their EGFR-TKI to their duration of osimertinib therapy. Adverse events were recorded by type and grading of severity using CTCAE grading scale with 1 being the least severe and 5 being death. Main Results: The 307 patients in the osimertinib as first-line therapy group had a median duration of therapy of 225 days compared to 191 patients in the EGFR-TKI + osimertinib who had a median duration of therapy of 701 days (p-value<0.0001, z-score -14.58). There were 340 adverse events reported (p=0.95) in the osimertinib first-line group with an average grading of 1.6 as compared to 210 adverse events reported in the EGFR-TKI + osimertinib group who had an average grading of 1.6 (p=1). Conclusions: Patients taking osimertinib as a first-line therapy experienced a far shorter duration of therapy than patients who started and failed a standard EGFR-TKI before starting osimertinib in patients with NSCLC in a real-world setting at a specialty pharmacy. There was no difference in adverse events reported between the two groups when considering sample size.