8.1Pregnancy Risk Summary
Teriflunomide tablets are contraindicated for use in pregnant women and females of reproductive potential not using effective contraception because of the potential for fetal harm based on animal data [see Contraindications (4) and Warnings and Precautions (5.2) ]. In animal reproduction studies in rat and rabbit, oral administration of teriflunomide during organogenesis caused teratogenicity and embryolethality at plasma exposures (AUC) lower than that at the maximum recommended human dose (MRHD) of 14 mg/day [see Data].
Available human data from pregnancy registries, clinical trials, pharmacovigilance cases, and published literature are too limited to draw any conclusions, but they do not clearly indicate increased birth defects or miscarriage associated with inadvertent teriflunomide exposure in the early first trimester when followed by an accelerated elimination procedure [see Clinical Considerations and Data]. There are no human data pertaining to exposures later in the first trimester or beyond.
In the US general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% -4% and 15% - 20%, respectively. The background risk of major birth defects and miscarriage in the indicated population is unknown. Clinical Considerations Fetal/Neonatal adverse reactions Lowering the plasma concentration of teriflunomide by instituting an accelerated drug elimination procedure as soon as pregnancy is detected may decrease the risk to the fetus from teriflunomide tablets.
The accelerated drug elimination procedure includes verification that the plasma teriflunomide concentration is less than 0.02 mg/L [see Warnings and Precautions (5.3) and Clinical Pharmacology (12.3) ]. Data Human data Available human data are limited. Prospectively reported data (from clinical trials and postmarketing reports) from >150 pregnancies in patients treated with teriflunomide and >300 pregnancies in patients treated with leflunomide have not demonstrated an increased rate of congenital malformations or miscarriage following teriflunomide exposure in the early first trimester when followed by an accelerated elimination procedure.
Specific patterns of major congenital malformations in humans have not been observed. Limitations of these data include an inadequate number of reported pregnancies from which to draw conclusions, the short duration of drug exposure in reported pregnancies, which precludes a full evaluation of the fetal risks, incomplete reporting, and the inability to control for confounders (such as underlying maternal disease and use of concomitant medications).
Animal data When teriflunomide (oral doses of 1, 3, or 10 mg/kg/day) was administered to pregnant rats throughout the period of organogenesis, high incidences of fetal malformation (primarily craniofacial, and axial and appendicular skeletal defects) and fetal death were observed at doses not associated with maternal toxicity. Adverse effects on fetal development were observed following dosing at various stages throughout organogenesis.
Maternal plasma exposure at the no-effect level (1.0 mg/kg/day) for fetal developmental toxicity in rats was less than that in humans at the maximum recommended human dose (MRHD, 14 mg/day). Administration of teriflunomide (oral doses of 1, 3.5, or 12 mg/kg/day) to pregnant rabbits throughout organogenesis resulted in high incidences of fetal malformation (primarily craniofacial, and axial and appendicular skeletal defects) and fetal death at doses associated with minimal maternal toxicity.
Maternal plasma exposure at the no-effect dose (1.0 mg/kg/day) for fetal developmental toxicity in rabbits was less than that in humans at the MRHD. In studies in which teriflunomide (oral doses of 0.05, 0.1, 0.3, 0.6, or 1.0 mg/kg/day) was administered to rats during gestation and lactation, decreased growth, eye and skin abnormalities, and high incidences of malformation (limb defects) and postnatal death were observed in the offspring at doses not associated with maternal toxicity.
Maternal plasma exposure at the no-effect dose for prenatal and postnatal developmental toxicity in rats (0.10 mg/kg/day) was less than that in humans at the MRHD. In animal reproduction studies of leflunomide, embryolethality and teratogenic effects were observed in pregnant rat and rabbit at or below clinically relevant plasma teriflunomide exposures (AUC). In published reproduction studies in pregnant mice, leflunomide was embryolethal and increased the incidence of malformations (craniofacial, axial skeletal, heart and great vessel).
Supplementation with exogenous uridine reduced the teratogenic effects in pregnant mice, suggesting that the mode of action (inhibition of mitochondrial enzyme dihydroorotate dehydrogenase) is the same for therapeutic efficacy and developmental toxicity. At recommended doses in humans, teriflunomide and leflunomide result in a similar range of plasma concentrations of teriflunomide.
