Influence of mild and moderate hepatic impairment on the pharmacokinetics (PK) of the pan-HER inhibitor dacomitinib.

Abstract

2568 Background: Dacomitinib (D) is a highly selective irreversible small molecule inhibitor of the HER family of tyrosine kinases in clinical development for NSCLC.Prior clinical studies of D, which has minimal renal excretion (~3%), enrolled pts with protocol-defined adequate liver function. Liver metastases, leading to abnormal liver function tests, are common in pts with advanced cancer. This study evaluated the effect of hepatic impairment on PK and safety of D following a single oral dose in subjects with mild or moderate hepatic impairment. Methods: In this phase I, open-label, parallel group study, 25 subjects with either normal hepatic function (n=8) or mild (Child-Pugh A; n=8) or moderate (Child-Pugh B; n=9) hepatic impairment were administered a single, oral dose of D (30 mg). PK samples were collected at intervals up to 264 h post-dose and safety was assessed by laboratory abnormalities, physical examination, vital signs, ECGs, and AE monitoring. Analysis of variance was performed on natural log-transformed AUC and Cmaxto estimate adjusted mean differences between groups and 90% CIs, which were exponentiated to produce the adjusted GMR and 90% CI of the ratios. Results: GMR and 90% CI for AUCinf and Cmax (preliminary analyses) are listed.Mean D exposure (AUCinf and Cmax) was similar in subjects with normal hepatic function and those with mild impairment. Moderate hepatic impairment decreased D exposure by 15% and 20% for AUCinf and Cmax, respectively, vs normal hepatic function, but the 90% CI was relatively wide, and included 1. Plasma protein binding of D was similar in the 3 groups. No clinically significant treatment-related AEs were reported. Conclusions: Mean D exposure (AUCinf and Cmax) was similar in subjects with normal hepatic function and those with mild impairment. Mean D exposure appeared slightly lower in subjects with moderate impairment. Dose reduction of D in subjects with mild or moderate hepatic impairment may not be necessary. A single 30 mg dose of D was well tolerated in subjects with mild or moderate hepatic impairment. Clinical trial information: NCT01571388. [Table: see text]