Absorption
Erlotinib is about 60% absorbed after oral administration. Peak plasma levels occur 4 hours after dosing.
Effect of Food
Food increased the bioavailability of erlotinib to approximately 100%.
Distribution:
Erlotinib is 93% protein bound to plasma albumin and alpha-1 acid glycoprotein (AAG).
Erlotinib has an apparent volume of distribution of 232 liters.
Elimination
Erlotinib is eliminated with a median half-life of 36.2 hours in patients receiving the single-agent erlotinib tablets 2nd/3rd line regimen. Time to reach steady state plasma concentration would therefore be 7 to 8 days.
Metabolism
Erlotinib is metabolized primarily by CYP3A4 and to a lesser extent by CYP1A2, and the extrahepatic isoform CYP1A1, in vitro.
Excretion
Following a 100 mg oral dose, 91% of the dose was recovered: 83% in feces (1% of the dose as intact parent) and 8% in urine (0.3% of the dose as intact parent).
Specific Populations
Neither age, body weight, nor gender had a clinically significant effect on the systemic exposure of erlotinib in NSCLC patients receiving single-agent erlotinib tablets for 2nd/3rd line treatment or for maintenance treatment, and in pancreatic cancer patients who received erlotinib plus gemcitabine. The pharmacokinetics of erlotinib tablets in patients with compromised renal function is unknown.
Patients with Hepatic Impairment
In vitro and in vivo evidence suggest that erlotinib is cleared primarily by the liver. However, erlotinib exposure was similar in patients with moderately impaired hepatic function (Child-Pugh B) compared with patients with adequate hepatic function including patients with primary liver cancer or hepatic metastases.
Patients That Smoke Tobacco Cigarettes
In a single-dose pharmacokinetics trial in healthy volunteers, cigarette smoking (moderate CYP1A2 inducer) increased erlotinib clearance and decreased erlotinib AUC0-inf by 64% (95% CI, 46 to 76%) in current smokers compared with former/never smokers. In a NSCLC trial, current smokers achieved erlotinib steady-state trough plasma concentrations which were approximately 2-fold less than the former smokers or patients who had never smoked. This effect was accompanied by a 24% increase in apparent erlotinib plasma clearance. In another study which was conducted in NSCLC patients who were current smokers, pharmacokinetic analyses at steady-state indicated a dose-proportional increase in erlotinib exposure when the erlotinib tablets dose was increased from 150 mg to 300 mg. [see Dosage and Administration (2.4), Drug Interactions (7) and Patient Counseling Information (17)].
Drug Interaction Studies
Co-administration of gemcitabine had no effect on erlotinib plasma clearance.
CYP3A4 Inhibitors
Co-administration with a strong CYP3A4 inhibitor, ketoconazole, increased erlotinib AUC by 67%. Co-administration with a combined CYP3A4 and CYP1A2 inhibitor, ciprofloxacin, increased erlotinib exposure [AUC] by 39%, and increased erlotinib maximum concentration [Cmax] by 17%. [see Dose Modifications (2.4), Drug Interactions (7)].
CYP3A4 Inducers
Pre-treatment with the CYP3A4 inducer rifampicin, for 7 to 11 days prior to erlotinib tablets, decreased erlotinib AUC by 58% to 80% [see Dose Modifications (2.4), Drug Interactions (7)].
CYP1A2 Inducers or Smoking Tobacco
See Specific Populations Section [see Dose Modifications (2.4), Drug Interactions (7)].
Drugs that Increase Gastric pH
Erlotinib solubility is pH dependent and decreases as pH increases. When a proton pump inhibitor (omeprazole) was co-administered with erlotinib tablets the erlotinib exposure [AUC] was decreased by 46% and the erlotinib maximum concentration [Cmax] was decreased by 61%. When erlotinib tablets were administered 2 hours following a 300 mg dose of an H-2 receptor antagonist (ranitidine), the erlotinib AUC was reduced by 33% and the erlotinib Cmax was reduced by 54%. When erlotinib tablets were administered with ranitidine 150 mg twice daily (at least 10 h after the previous ranitidine evening dose and 2 h before the ranitidine morning dose), the erlotinib AUC was decreased by 15% and the erlotinib Cmax was decreased by 17% [see Dose Modifications (2.4), Drug Interactions (7)].