title: Clinical Pharmacokinetics and Pharmacodynamics of Afatinib.
abstract: Afatinib is an oral, irreversible ErbB family blocker that covalently binds to the kinase domains of epidermal growth factor receptor (EGFR), human EGFRs (HER) 2, and HER4, resulting in irreversible inhibition of tyrosine kinase autophosphorylation. Studies in healthy volunteers and patients with advanced solid tumours have shown that once-daily afatinib has time-independent pharmacokinetic characteristics. Maximum plasma concentrations of afatinib are reached approximately 2-5 h after oral administration and thereafter decline, at least bi-exponentially. Food reduces total exposure to afatinib. Over the clinical dose range of 20-50 mg, afatinib exposure increases slightly more than dose proportional. Afatinib metabolism is minimal, with unchanged drug predominantly excreted in the faeces and approximately 5 % in urine. Apart from the parent drug afatinib, the major circulation species in human plasma are the covalently bound adducts to plasma protein. The effective elimination half-life is approximately 37 h, consistent with an accumulation of drug exposure by 2.5- to 3.4-fold based on area under the plasma concentration-time curve (AUC) after multiple dosing. The pharmacokinetic profile of afatinib is consistent across a range of patient populations. Age, ethnicity, smoking status and hepatic function had no influence on afatinib pharmacokinetics, while females and patients with low body weight had increased exposure to afatinib. Renal function is correlated with afatinib exposure, but, as for sex and body weight, the effect size for patients with severe renal impairment (approximately 50 % increase in AUC) is only mildly relative to the extent of unexplained interpatient variability in afatinib exposure. Afatinib has a low potential as a victim or perpetrator of drug-drug interactions, especially with cytochrome P450-modulating agents. However, concomitant treatment with potent inhibitors or inducers of the P-glycoprotein transporter can affect the pharmacokinetics of afatinib. At a dose of 50 mg, afatinib does not have proarrhythmic potential.
authors.affiliation: Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co KG, Birkendorfer Strasse 65, 88397, Biberach an der Riss, Germany. sven.wind@boehringer-ingelheim.com.
authors.forename: Sven
authors.initials: S
authors.lastname: Wind
authors.affiliation: Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co KG, Birkendorfer Strasse 65, 88397, Biberach an der Riss, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Schnell
authors.affiliation: Drug metabolism and Pharmacokinetics, Boehringer Ingelheim Pharma GmbH & Co KG, Birkendorfer Strasse 65, 88397, Biberach an der Riss, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ebner
authors.affiliation: Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co KG, Birkendorfer Strasse 65, 88397, Biberach an der Riss, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Freiwald
authors.affiliation: Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co KG, Birkendorfer Strasse 65, 88397, Biberach an der Riss, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Stopfer
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D000077716:Afatinib; D000818:Animals; D004347:Drug Interactions / Q000502:physiology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D009369:Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D047428:Protein Kinase Inhibitors / Q000493:pharmacokinetics / Q000627:therapeutic use; D011799:Quinazolines / Q000493:pharmacokinetics* / Q000627:therapeutic use; D011838:Radiation-Sensitizing Agents / Q000493:pharmacokinetics / Q000627:therapeutic use
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D011838:Radiation-Sensitizing Agents; D000077716:Afatinib; C512478:EGFR protein, human; D066246:ErbB Receptors