Azilect (Page 6 of 8)

12.3 Pharmacokinetics

Rasagiline in the range of 1-6 mg demonstrated a more than proportional increase in AUC, while Cmax was dose proportional. Rasagiline mean steady-state half life is 3 hours but there is no correlation of pharmacokinetics with its pharmacological effect because of its irreversible inhibition of MAO-B.

Absorption

Rasagiline is rapidly absorbed, reaching peak plasma concentration (Cmax) in approximately 1 hour. The absolute bioavailability of rasagiline is about 36%.

Food does not affect the Tmax of rasagiline, although Cmax and exposure (AUC) are decreased by approximately 60% and 20%, respectively, when the drug is taken with a high fat meal. Because AUC is not significantly affected, AZILECT can be administered with or without food.

Distribution

The mean volume of distribution at steady-state is 87 L, indicating that the tissue binding of rasagiline is in excess of plasma protein binding. Plasma protein binding ranges from 88-94% with mean extent of binding of 61-63% to human albumin over the concentration range of 1-100 ng/mL.

Metabolism and Elimination

Rasagiline undergoes almost complete biotransformation in the liver prior to excretion. The metabolism of rasagiline proceeds through two main pathways: N-dealkylation and/or hydroxylation to yield 1-aminoindan (AI), 3-hydroxy-N-propargyl-1 aminoindan (3-OH-PAI) and 3-hydroxy-1-aminoindan (3-OH-AI). In vitro experiments indicate that both routes of rasagiline metabolism are dependent on the cytochrome P450 (CYP) system, with CYP1A2 being the major isoenzyme involved in rasagiline metabolism. Glucuronide conjugation of rasagiline and its metabolites, with subsequent urinary excretion, is the major elimination pathway.

After oral administration of 14 C-labeled rasagiline, elimination occurred primarily via urine and secondarily via feces (62% of total dose in urine and 7% of total dose in feces over 7 days), with a total calculated recovery of 84% of the dose
over a period of 38 days. Less than 1% of rasagiline was excreted as unchanged drug in urine.

Specific Populations

Hepatic Impairment

Following repeat dose administration (7 days) of rasagiline (1 mg/day) in subjects with mild hepatic impairment (Child-Pugh score 5-6), AUC and Cmax were increased by 2 fold and 1.4 fold, respectively, compared to healthy subjects. In subjects with moderate hepatic impairment (Child-Pugh score 7-9), AUC and Cmax were increased by 7 fold and 2 fold, respectively, compared to healthy subjects [see Dosage and Administration (2.3) and Warnings and Precautions (5.5)].

Renal Impairment

Following repeat dose administration (8 days) of rasagiline (1 mg/day) in subjects with moderate renal impairment, rasagiline exposure (AUC) was similar to rasagiline exposure in healthy subjects, while the major metabolite 1-AI exposure (AUC) was increased 1.5- fold in subjects with moderate renal impairment, compared to healthy subjects. Because 1-AI is not an MAO inhibitor, no dose adjustment is needed for patients with mild and moderate renal impairment. Data are not available for patients with severe renal impairment.

Elderly

Since age has little influence on rasagiline pharmacokinetics, it can be administered at the recommended dose in the elderly (≥ 65 years).

Pediatric

AZILECT has not been investigated in patients below 18 years of age.

Gender

The pharmacokinetic profile of rasagiline is similar in men and women.

Drug-Drug Interactions

Levodopa

A study in Parkinson’s disease patients, in which the effect of levodopa/carbidopa (LD/CD) on rasagiline pharmacokinetics at steady state was investigated, showed that the pharmacokinetics of rasagiline were not affected by concomitant administration of LD/CD.

Effect of Other Drugs on the Metabolism of AZILECT

In vitro metabolism studies showed that CYP1A2 was the major enzyme responsible for the metabolism of rasagiline. There is the potential for inhibitors of this enzyme to alter AZILECT clearance when coadministered [see Dosage and Administration (2.2) and Warnings and Precautions (5.4)].

Ciprofloxacin: When ciprofloxacin, an inhibitor of CYP1A2, was administered to healthy volunteers (n=12) at 500 mg (BID) with rasagiline at 2 mg/day, the AUC of rasagiline increased by 83% and there was no change in the elimination half life [see Dosage and Administration (2.2) and Warnings and Precautions (5.4)].

Theophylline: Coadministration of rasagiline 1 mg/day and theophylline, a substrate of CYP1A2, up to 500 mg twice daily to healthy subjects (n=24) did not affect the pharmacokinetics of either drug.

Antidepressants: Severe CNS toxicity (occasionally fatal) associated with hyperpyrexia as part of a serotonin syndrome, has been reported with combined treatment of an antidepressant (e.g., from one of many classes including tricyclic or tetracyclic antidepressants, SSRIs, SNRIs, triazolopyridine antidepressants) and nonselective MAOI or a selective MAO-B inhibitor [see Warnings and Precautions (5.2)].

Effect of AZILECT on Other Drugs

No additional in vivo trials have investigated the effect of AZILECT on other drugs metabolized by the cytochrome P450 enzyme system. In vitro studies showed that rasagiline at a concentration of 1 mcg/mL (equivalent to a level that is 160 times the average Cmax ~ 5.9-8.5 ng/mL in Parkinson’s disease patients after 1 mg rasagiline multiple dosing) did not inhibit cytochrome P450 isoenzymes, CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4 and CYP4A. These results indicate that rasagiline is unlikely to cause any clinically significant interference with substrates of these enzymes.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis

Two-year carcinogenicity studies were conducted in mice at oral doses of 0, 1, 15, and 45 mg/kg/day and in rats at oral doses of 0.3, 1, and 3 mg/kg/day (males) or 0, 0.5, 2, 5, and 17 mg/kg/day (females). In rats, there was no increase in tumors at any dose tested. Plasma exposures (AUC) at the highest dose tested were approximately 33 and 260 times, in male and female rats, respectively, that in humans at the maximum recommended human dose (MRHD) of 1 mg/day.

In mice, there was an increase in lung tumors (combined adenomas/carcinomas) at 15 and 45 mg/kg in males and females. At the lowest dose tested, plasma AUCs were approximately 5 times those expected in humans at the MRHD.

The carcinogenic potential of rasagiline administered in combination with levodopa/carbidopa has not been examined.

Mutagenesis

Rasagiline was reproducibly clastogenic in in vitro chromosomal aberration assays in human lymphocytes in the presence of metabolic activation and was mutagenic and clastogenic in the in vitro mouse lymphoma tk assay in the absence and presence of metabolic activation. Rasagiline was negative in the in vitro bacterial reverse mutation (Ames) assay and in the in vivo micronucleus assay in mice. Rasagiline was also negative in the in vivo micronucleus assay in mice when administered in combination with levodopa/carbidopa.

Impairment of Fertility

Rasagiline had no effect on mating performance or fertility in rats treated prior to and throughout the mating period and continuing in females through gestation day 17 at oral doses of up to 3 mg/kg/day (approximately 30 times the plasma AUC in humans at the MRHD). The effect of rasagiline administered in combination with levodopa/carbidopa on mating and fertility has not been examined.

14 CLINICAL STUDIES

The effectiveness of AZILECT for the treatment of Parkinson’s disease was established in four 18- to 26-week, randomized, placebo-controlled trials, as initial monotherapy or adjunct therapy.

14.1 Monotherapy Use of AZILECT

Study 1 was a double-blind, randomized, fixed-dose parallel group, 26-week study in early Parkinson’s disease patients not receiving any concomitant dopaminergic therapy at the start of the study. The majority of the patients were not treated with medications for Parkinson’s disease before receiving AZILECT.

In Study 1, 404 patients were randomly assigned to receive placebo (138 patients), AZILECT 1 mg/day (134 patients) or AZILECT 2 mg/day (132 patients). Patients were not allowed to take levodopa, dopamine agonists, selegiline, or amantadine, but could take stable doses of anticholinergic medication, if necessary. The average Parkinson’s disease duration was approximately 1 year (range 0 to 11 years).

The primary measure of effectiveness was the change from baseline in the total score of the Unified Parkinson’s Disease Rating Scale (UPDRS), [mentation (Part I) + activities of daily living (ADL) (Part II) + motor function (Part III)]. The UPDRS is a multi-item rating scale that measures the ability of a patient to perform mental and motor tasks as well as activities of daily living. A reduction in the score represents improvement and a beneficial change from baseline appears as a negative number.

AZILECT (1 or 2 mg once daily) was superior to placebo on the primary measure of effectiveness in patients receiving six months of treatment and not on dopaminergic therapy. The effectiveness of AZILECT 1 mg and 2 mg was comparable. Table 4 shows the results of Study 1. There were no differences in effectiveness based on age or gender between AZILECT 1 mg/day and placebo.

Table 4: Change in Total UPDRS Score in Study 1

Baseline score

Change from baseline to termination score

p-value vs. placebo

Placebo

24.5

3.9

AZILECT 1 mg

24.7

0.1

0.0001

AZILECT 2 mg

25.9

0.7

0.0001

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