Low plasma concentration of gefitinib in patients with EGFR exon 21 L858R point mutations shortens progression-free survival

Purpose The relationship between the pharmacokinetics and effects of gefitinib in patients with epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) is unknown. In this study, we examined the correlation between gefitinib plasma concentration and progression-free survival (PFS) in patients with two common types of EGFR mutations: a deletion in exon 19 and point mutations in exon 21 L858R.