Teriflunomide is the principal active metabolite of leflunomide and is responsible for leflunomide’s activity
in vivo. At recommended doses, teriflunomide and leflunomide result in a similar range of plasma concentrations of teriflunomide.
Based on a population analysis of teriflunomide in healthy adult volunteers and adult MS patients, median t
1/2 was approximately 18 and 19 days after repeated doses of 7 mg and 14 mg respectively. It takes approximately 3 months respectively to reach steady-state concentrations. The estimated AUC accumulation ratio is approximately 30 after repeated doses of 7 or 14 mg.
Absorption
Median time to reach maximum plasma concentrations is between 1 to 4 hours post dose following oral administration of teriflunomide.
Food does not have a clinically relevant effect on teriflunomide pharmacokinetics.
Distribution
Teriflunomide is extensively bound to plasma protein (>99%) and is mainly distributed in plasma. The volume of distribution is 11 L after a single intravenous (IV) administration.
Metabolism
Teriflunomide is the major circulating moiety detected in plasma. The primary biotransformation pathway to minor metabolites of teriflunomide is hydrolysis, with oxidation being a minor pathway. Secondary pathways involve oxidation, N-acetylation and sulfate conjugation.
Elimination
Teriflunomide is eliminated mainly through direct biliary excretion of unchanged drug as well as renal excretion of metabolites. Over 21 days, 60.1% of the administered dose is excreted via feces (37.5%) and urine (22.6%). After an accelerated elimination procedure with cholestyramine, an additional 23.1% was recovered (mostly in feces). After a single IV administration, the total body clearance of teriflunomide is 30.5 mL/h.
Drug Interaction Studies
Teriflunomide is not metabolized by Cytochrome P450 or flavin monoamine oxidase enzymes.
The potential effect of teriflunomide on other drugs
CYP2C8 substrates
There was an increase in mean repaglinide C
maxand AUC (1.7- and 2.4-fold, respectively) following repeated doses of teriflunomide and a single dose of 0.25 mg repaglinide, suggesting that teriflunomide is an inhibitor of CYP2C8
in vivo. The magnitude of interaction could be higher at the recommended repaglinide dose
[see Drug Interactions (
7)].
CYP1A2 substrates
Repeated doses of teriflunomide decreased mean C
maxand AUC of caffeine by 18% and 55%, respectively, suggesting that teriflunomide may be a weak inducer of CYP1A2
in vivo [see Drug Interactions (
7)].
OAT3 substrates
There was an increase in mean cefaclor C
maxand AUC (1.43- and 1.54-fold, respectively), following repeated doses of teriflunomide, suggesting that teriflunomide is an inhibitor of organic anion transporter 3 (OAT3)
in vivo
[see Drug Interactions (
7)].
BCRP and OATP1B1/1B3 substrates
There was an increase in mean rosuvastatin C
maxand AUC (2.65- and 2.51-fold, respectively) following repeated doses of teriflunomide, suggesting that teriflunomide is an inhibitor of BCRP transporter and organic anion transporting polypeptide 1B1 and 1B3 (OATP1B1/1B3)
[see Drug Interactions (
7)].
Oral contraceptives
There was an increase in mean ethinylestradiol C
maxand AUC
0 to 24(1.58- and 1.54-fold, respectively) and levonorgestrel C
maxand AUC
0 to 24(1.33- and 1.41-fold, respectively) following repeated doses of teriflunomide
[see Drug Interactions (
7)].
Teriflunomide did not affect the pharmacokinetics of bupropion (a CYP2B6 substrate), midazolam (a CYP3A4 substrate), S-warfarin (a CYP2C9 substrate), omeprazole (a CYP2C19 substrate), and metoprolol (a CYP2D6 substrate).
The potential effect of other drugs on teriflunomide
Potent CYP and transporter inducers: Rifampin did not affect the pharmacokinetics of teriflunomide.
Specific Populations
Hepatic impairment
Mild and moderate hepatic impairment had no impact on the pharmacokinetics of teriflunomide. The pharmacokinetics of teriflunomide in severe hepatic impairment has not been evaluated
[see Contraindications (
4), Warnings and Precautions (
5.1), and Use in Specific Populations (
8.6)].
Renal impairment
Severe renal impairment had no impact on the pharmacokinetics of teriflunomide
[see Use in Specific Populations (
8.7)].
Gender
In a population analysis, the clearance rate for teriflunomide is 23% less in females than in males.
Race
Effect of race on the pharmacokinetics of teriflunomide cannot be adequately assessed due to a low number of patients who self-identified as Black or African American, Asian, or other races in the clinical trials.