Risk Summary
Based on findings from animal studies and its mechanism of action, VIZIMPRO can cause fetal harm when administered to a pregnant woman [see Clinical Pharmacology (12.1)]. There are no available data on VIZIMPRO use in pregnant women. In animal reproduction studies, oral administration of dacomitinib to pregnant rats during the period of organogenesis resulted in an increased incidence of post-implantation loss and reduced fetal body weight at doses resulting in exposures near the exposure at the 45 mg human dose (see Data). The absence of EGFR signaling has been shown to result in embryolethality as well as post-natal death in animals (see Data). Advise pregnant women of the potential risk to a fetus [see Use in Special Populations (8.3)].
In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Data
Animal Data
Daily oral administration of dacomitinib to pregnant rats during the period of organogenesis resulted in an increased incidence of post-implantation loss, maternal toxicity, and reduced fetal body weight at 5 mg/kg/day (approximately 1.2 times the exposure based on area under the curve [AUC] at the 45 mg human dose).
Disruption or depletion of EGFR in mouse models has shown EGFR is critically important in reproductive and developmental processes including blastocyst implantation, placental development, and embryo-fetal/post-natal survival and development. Reduction or elimination of embryo-fetal or maternal EGFR signaling in mice can prevent implantation, and can cause embryo-fetal loss during various stages of gestation (through effects on placental development), developmental anomalies, early death in surviving fetuses, and adverse developmental outcomes in multiple organs in embryos/neonates.
Risk Summary
There is no information regarding the presence of dacomitinib or its metabolites in human milk or their effects on the breastfed infant or on milk production. Because of the potential for serious adverse reactions in breastfed infants from VIZIMPRO, advise women not to breastfeed during treatment with VIZIMPRO and for at least 17 days after the last dose.
Pregnancy Testing
Verify the pregnancy status of females of reproductive potential prior to initiating VIZIMPRO [see Use in Specific Populations (8.1)].
Contraception
VIZIMPRO can cause fetal harm when administered to a pregnant woman [see Use in Specific Populations (8.1)].
Females
Advise females of reproductive potential to use effective contraception during treatment with VIZIMPRO and for at least 17 days after the final dose.
Cardiac Electrophysiology
The effect of dacomitinib on the QT interval corrected for heart rate (QTc) was evaluated using time-matched electrocardiograms (ECGs) evaluating the change from baseline and corresponding pharmacokinetic data in 32 patients with advanced NSCLC. Dacomitinib had no large effect on QTc (i.e., >20 ms) at maximum dacomitinib concentrations achieved with VIZIMPRO 45 mg orally once daily.
Exposure-Response Relationships
Higher exposures, across the range of exposures with the recommended dose of 45 mg daily, correlated with an increased probability of Grade ≥3 adverse events, specifically dermatologic toxicities and diarrhea.
Absorption
The mean absolute bioavailability of dacomitinib is 80% after oral administration. The median dacomitinib time to reach maximum concentration (Tmax) occurred at approximately 6.0 hours (range 2.0 to 24 hours) after a single oral dose of VIZIMPRO 45 mg in patients with cancer.
Effect of Food
Administration of VIZIMPRO with a high-fat, high-calorie meal (approximately 800 to 1000 calories with 150, 250, and 500 to 600 calories from protein, carbohydrate and fat, respectively) had no clinically meaningful effect on dacomitinib pharmacokinetics.
Distribution
The geometric mean (CV%) volume of distribution of dacomitinib (Vss) was 1889 L (18%). In vitro binding of dacomitinib to human plasma proteins is approximately 98% and is independent of drug concentrations from 250 ng/mL to 1000 ng/mL.
Elimination
Following a single 45 mg oral dose of VIZIMPRO in patients with cancer, the mean (CV%) plasma half-life of dacomitinib was 70 hours (21%), and the geometric mean (CV%) apparent plasma clearance of dacomitinib was 24.9 L/h (36%).
Metabolism
Hepatic metabolism is the main route of clearance of dacomitinib, with oxidation and glutathione conjugation as the major pathways. Following oral administration of a single 45 mg dose of [14C] dacomitinib, the most abundant circulating metabolite was O-desmethyl dacomitinib, which had similar in vitro pharmacologic activity as dacomitinib. The steady-state plasma trough concentration of O-desmethyl dacomitinib ranges from 7.4% to 19% of the parent. In vitro studies indicated that cytochrome P450 (CYP) 2D6 was the major isozyme involved in the formation of O-desmethyl dacomitinib, while CYP3A4 contributed to the formation of other minor oxidative metabolites.
Excretion
Following a single oral 45 mg dose of [14C] radiolabeled dacomitinib, 79% of the radioactivity was recovered in feces (20% as dacomitinib) and 3% in urine (<1% as dacomitinib).
Specific Populations
Patients with Renal Impairment
Based on population pharmacokinetic analyses, mild (60 mL/min ≤ CLcr <90 mL/min; N=590) and moderate (30 mL/min ≤ CLcr <60 mL/min; N=218) renal impairment did not alter dacomitinib pharmacokinetics, relative to the pharmacokinetics in patients with normal renal function (CLcr ≥90 mL/min; N=567). The pharmacokinetics of dacomitinib has not been adequately characterized in patients with severe renal impairment (CLcr <30 mL/min) (N=4) or studied in patients requiring hemodialysis.
Patients with Hepatic Impairment
In a dedicated hepatic impairment trial, following a single oral dose of 30 mg VIZIMPRO, dacomitinib exposure (AUCinf and Cmax) was unchanged in subjects with mild hepatic impairment (Child-Pugh A; N=8) and decreased by 15% and 20%, respectively in subjects with moderate hepatic impairment (Child-Pugh B; N=9) when compared to subjects with normal hepatic function (N=8). Based on this trial, mild and moderate hepatic impairment had no clinically important effects on pharmacokinetics of dacomitinib. In addition, based on a population pharmacokinetic analysis of 1381 patients, in which 158 patients had mild hepatic impairment (total bilirubin ≤ ULN and AST > ULN, or total bilirubin > 1 to 1.5 × ULN with any AST) and 5 patients had moderate hepatic impairment (total bilirubin > 1.5 to 3 × ULN and any AST), no effects on pharmacokinetics of dacomitinib were observed. The effect of severe hepatic impairment (total bilirubin > 3 to 10 × ULN and any AST) on dacomitinib pharmacokinetics is unknown [see Use in Specific Populations (8.7)].
Drug Interaction Studies
Clinical Studies
Effect of Acid-Reducing Agents on Dacomitinib
Coadministration of a single 45 mg dose of VIZIMPRO with multiple doses of rabeprazole (a proton pump inhibitor) decreased dacomitinib Cmax by 51% and AUC0–96h by 39% [see Dosage and Administration (2.4) and Drug Interactions (7.1)].
Coadministration of VIZIMPRO with a local antacid (Maalox® Maximum Strength, 400 mg/5 mL) did not cause clinically relevant changes dacomitinib concentrations [see Dosage and Administration (2.4) and Drug Interactions (7.1)].
The effect of H2 receptor antagonists on dacomitinib pharmacokinetics has not been studied [see Dosage and Administration (2.4) and Drug Interactions (7.1)].
Effect of Strong CYP2D6 Inhibitors on Dacomitinib
Coadministration of a single 45 mg dose of VIZIMPRO with multiple doses of paroxetine (a strong CYP2D6 inhibitor) in healthy subjects increased the total AUClast of dacomitinib plus its active metabolite (O-desmethyl dacomitinib) in plasma by approximately 6%, which is not considered clinically relevant.
Effect of Dacomitinib on CYP2D6 Substrates
Coadministration of a single 45 mg oral dose of VIZIMPRO increased dextromethorphan (a CYP2D6 substrate) Cmax by 9.7-fold and AUClast by 9.6-fold [see Drug Interactions (7.2)].
In Vitro Studies
Effect of Dacomitinib and O-desmethyl Dacomitinib on CYP Enzymes: Dacomitinib and its metabolite O-desmethyl dacomitinib do not inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, or CYP3A4/5. Dacomitinib does not induce CYP1A2, CYP2B6, or CYP3A4.
Effect of Dacomitinib on Uridine 5' diphospho-glucuronosyltransferase (UGT) Enzymes: Dacomitinib inhibits UGT1A1. Dacomitinib does not inhibit UGT1A4, UGT1A6, UGT1A9, UGT2B7, or UGT2B15.
Effect of Dacomitinib on Transporter Systems: Dacomitinib is a substrate for the membrane transport protein P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP). Dacomitinib inhibits P-gp, BCRP, and organic cation transporter (OCT)1. Dacomitinib does not inhibit organic anion transporters (OAT)1 and OAT3, OCT2, organic anion transporting polypeptide (OATP)1B1, and OATP1B3.
Interstitial Lung Disease (ILD)