Osimertinib vs. afatinib as first-line treatment for patients with metastatic non-small cell lung cancer with an EGFR exon 19 deletion or exon 21 L858R mutation.

ABSTRACT

Background: The optimal treatment sequencing for patients with metastatic epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) remains a subject of debate. In the United States, osimertinib is the preferred EGFR tyrosine kinase inhibitor (TKI) in the first-line setting. However, small retrospective studies suggest that alternative EGFR TKI sequencing strategies may produce similar outcomes. This study aimed to compare the outcomes of patients with metastatic NSCLC harboring an EGFR exon 19 deletion or exon 21 L858R mutation treated with osimertinib vs. afatinib as first-line therapy. Methods: This retrospective, single-institution study examined 86 patients with metastatic EGFR-mutant NSCLC treated with either afatinib (n=15) or osimertinib (n=71) in the first-line setting. The primary outcome was progression-free survival (PFS), and secondary endpoints included time on EGFR TKI, overall survival (OS), and the incidence of adverse events (AEs). Results: There was no difference in the PFS (median 27.9 vs. 29.0 months, P=0.75), OS (P=0.18), and the median time on first-line EGFR TKI (23.9 vs. 15.2 months, P=0.10) between the afatinib and osimertinib groups, respectively. The number of AEs was also similar between the two treatment groups (P=0.17). Conclusions: In this real-world retrospective study, there were no differences in PFS or OS between patients treated with afatinib or osimertinib in the first-line setting. These findings should be further investigated in larger prospective studies.