The Effect of Hepatic Impairment on the Pharmacokinetics of Dacomitinib

BACKGROUND AND OBJECTIVE: Dacomitinib is a kinase inhibitor indicated for the first-line treatment of patients with metastatic non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR)-activating mutations. To evaluate the effect of hepatic impairment on the pharmacokinetics of dacomitinib, two dedicated studies were conducted to inform optimal dosing. METHODS: Study 1 (NCT01571388) evaluated the effect of mild and moderate hepatic impairment on the plasma pharmacokinetics, safety, and tolerability after a single oral dose of dacomitinib 30 mg, and Study 2 (NCT03865446) evaluated the same endpoints in a severe hepatic impairment population. Both studies were phase I, open-label, parallel-group studies. A one-way analysis of variance (ANOVA) with unequal variance assumption and hepatic impairment group as a fixed effect was used to compare the natural log of area under the plasma concentration-time curve extrapolated to infinite time (AUC(inf)), AUC from time zero to the last quantifiable concentration (AUC(last)), and maximum plasma concentration (C(max)) for each hepatic impairment group to the respective normal hepatic function group. Since dacomitinib is a cytochrome P450 (CYP) 2D6 substrate, only participants with extensive or intermediate CYP2D6 phenotypes were included in the primary analysis. RESULTS: The AUC(inf) for participants with mild, moderate, or severe hepatic impairment decreased by 6%, decreased by 23%, and increased by 4%, respectively, compared with normal hepatic function, while the C(max) for participants with mild, moderate, or severe hepatic impairment increased by 3%, decreased by 20%, and increased by 31%, respectively, compared with normal hepatic function. A single oral dose of dacomitinib 30 mg was well tolerated in all participants. CONCLUSION: Based on these pharmacokinetic results, dacomitinib pharmacokinetics of participants with mild, moderate, or severe hepatic impairment were not statistically different relative to participants with normal hepatic function based on the ANOVA analysis. No dacomitinib dose adjustments for patients with hepatic impairment are recommended. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT01571388, registered 5 April 2012; ClinicalTrials.gov NCT03865446, registered 6 March 2019. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40261-022-01125-x.