TARCEVA (Page 5 of 9)

8.6 Hepatic Impairment

Hepatic failure and hepatorenal syndrome, including fatal cases, can occur with TARCEVA treatment in patients with normal hepatic function; the risk of hepatic toxicity is increased in patients with baseline hepatic impairment [see Warnings and Precautions (5.3), Adverse Reactions (6.1, 6.2), and Dosage and Administration]. Monitor patients with hepatic impairment (total bilirubin greater than upper limit of normal (ULN) or Child-Pugh A, B and C) during therapy with TARCEVA. Treatment with TARCEVA should be used with increased monitoring in patients with total bilirubin greater than 3 x ULN [see Warnings and Precautions (5.3), Adverse Reactions (6.1, 6.2), and Dosage and Administration (2.4)].

10 OVERDOSAGE

Withhold TARCEVA in patients with an overdose or suspected overdose and institute symptomatic treatment.

11 DESCRIPTION

TARCEVA (erlotinib), a kinase inhibitor, is a quinazolinamine with the chemical name N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy)-4-quinazolinamine. TARCEVA contains erlotinib as the hydrochloride salt that has the following structural formula:

Erlotinib Structural Formula

Erlotinib hydrochloride has the molecular formula C22 H23 N3 O4 .HCl and a molecular weight of 429.90. The molecule has a pKa of 5.42 at 25°C. Erlotinib hydrochloride is very slightly soluble in water, slightly soluble in methanol and practically insoluble in acetonitrile, acetone, ethyl acetate and hexane.

Aqueous solubility of erlotinib hydrochloride is dependent on pH with increased solubility at a pH of less than 5 due to protonation of the secondary amine. Over the pH range of 1.4 to 9.6, maximal solubility of approximately 0.4 mg/mL occurs at a pH of approximately 2.

TARCEVA tablets for oral administration are available in three dosage strengths containing erlotinib hydrochloride (27.3 mg, 109.3 mg and 163.9 mg) equivalent to 25 mg, 100 mg and 150 mg erlotinib and the following inactive ingredients: lactose monohydrate, hypromellose, hydroxypropyl cellulose, magnesium stearate, microcrystalline cellulose, sodium starch glycolate, sodium lauryl sulfate and titanium dioxide. The tablets also contain trace amounts of color additives, including FD&C Yellow #6 (25 mg only) for product identification.

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Epidermal growth factor receptor (EGFR) is expressed on the cell surface of both normal and cancer cells. In some tumor cells signaling through this receptor plays a role in tumor cell survival and proliferation irrespective of EGFR mutation status. Erlotinib reversibly inhibits the kinase activity of EGFR, preventing autophosphorylation of tyrosine residues associated with the receptor and thereby inhibiting further downstream signaling. Erlotinib binding affinity for EGFR exon 19 deletion or exon 21 (L858R) mutations is higher than its affinity for the wild type receptor. Erlotinib inhibition of other tyrosine kinase receptors has not been fully characterized.

12.3 Pharmacokinetics

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 TARCEVA 2nd /3rd line regimen. Time to reach steady state plasma concentration would therefore be 7-8 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 TARCEVA for 2nd /3rd line treatment or for maintenance treatment, and in pancreatic cancer patients who received erlotinib plus gemcitabine. The pharmacokinetics of TARCEVA 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, 46-76%) 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 TARCEVA 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 7-11 days prior to TARCEVA, 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 TARCEVA the erlotinib exposure [AUC] was decreased by 46% and the erlotinib maximum concentration [Cmax ] was decreased by 61%. When TARCEVA was 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 TARCEVA was 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)].

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