Cardiovascular Deaths
Four cardiovascular deaths, including three sudden deaths, and one myocardial infarction in a patient with a history of hyperlipidemia and hypertension were reported among approximately 2600 patients exposed to teriflunomide in the premarketing database. These cardiovascular deaths occurred during uncontrolled extension studies, one to nine years after initiation of treatment. A relationship between teriflunomide and cardiovascular death has not been established.
Acute Renal Failure
In placebo-controlled studies, creatinine values increased more than 100% over baseline in 8/1045 (0.8%) patients in the 7 mg teriflunomide group and 6/1002 (0.6%) patients in the 14 mg teriflunomide group versus 4/997 (0.4%) patients in the placebo group. These elevations were transient. Some elevations were accompanied by hyperkalemia. Teriflunomide may cause acute uric acid nephropathy with transient acute renal failure because teriflunomide increases renal uric acid clearance.
Hypophosphatemia
In clinical trials, 18% of teriflunomide-treated patients had hypophosphatemia with serum phosphorus levels of at least 0.6 mmol/L, compared to 7% of placebo-treated patients; 4% of teriflunomide-treated patients had hypophosphatemia with serum phosphorus levels at least 0.3 mmol/L but less than 0.6 mmol/L, compared to 0.8% of placebo-treated patients. No patient in any treatment group had a serum phosphorus below 0.3 mmol/L.
Effect of Teriflunomide on CYP2C8 Substrates
Teriflunomide is an inhibitor of CYP2C8 in vivo. In patients taking teriflunomide, exposure of drugs metabolized by CYP2C8 (e.g., paclitaxel, pioglitazone, repaglinide, rosiglitazone) may be increased. Monitor these patients and adjust the dose of the concomitant drug(s) metabolized by CYP2C8 as required [see Clinical Pharmacology (12.3)].
Effect of Teriflunomide on Warfarin
Coadministration of teriflunomide with warfarin requires close monitoring of the international normalized ratio (INR) because teriflunomide may decrease peak INR by approximately 25%.
Effect of Teriflunomide on Oral Contraceptives
Teriflunomide may increase the systemic exposures of ethinylestradiol and levonorgestrel. Consideration should be given to the type or dose of contraceptives used in combination with teriflunomide [see Clinical Pharmacology (12.3)].
Effect of Teriflunomide on CYP1A2 Substrates
Teriflunomide may be a weak inducer of CYP1A2 in vivo. In patients taking teriflunomide, exposure of drugs metabolized by CYP1A2 (e.g., alosetron, duloxetine, theophylline, tizanidine) may be reduced. Monitor these patients and adjust the dose of the concomitant drug(s) metabolized by CYP1A2 as required [see Clinical Pharmacology (12.3)].
Effect of Teriflunomide on Organic Anion Transporter 3 (OAT3) Substrates
Teriflunomide inhibits the activity of OAT3 in vivo. In patients taking teriflunomide, exposure of drugs which are OAT3 substrates (e.g., cefaclor, cimetidine, ciprofloxacin, penicillin G, ketoprofen, furosemide, methotrexate, zidovudine) may be increased. Monitor these patients and adjust the dose of the concomitant drug(s) which are OAT3 substrates as required [see Clinical Pharmacology (12.3)].
- Effect of Teriflunomide on BCRP and Organic Anion Transporting Polypeptide B1 and B3 (OATP1B1/1B3) Substrates
Teriflunomide inhibits the activity of BCRP and OATP1B1/1B3 in vivo. For a patient taking teriflunomide, the dose of rosuvastatin should not exceed 10 mg once daily. For other substrates of BCRP (e.g., mitoxantrone) and drugs in the OATP family (e.g., methotrexate, rifampin), especially HMG-Co reductase inhibitors (e.g., atorvastatin, nateglinide, pravastatin, repaglinide, and simvastatin), consider reducing the dose of these drugs and monitor patients closely for signs and symptoms of increased exposures to the drugs while patients are taking teriflunomide [see Clinical Pharmacology (12.3)].
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 Cmax and 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 Cmax and 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 Cmax and 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 Cmax and 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 Cmax and AUC0–24 (1.58- and 1.54-fold, respectively) and levonorgestrel Cmax and AUC0–24 (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 non-white patients in the clinical trials.