Treprostinil

When co-administered with strong CYP2C8 inhibitors the initial dose is 0.125 mg BID with 0.125 mg BID dose increments not more frequently than every 3 to 4 days. ( 2.4 , 7.1 )

7.1 Effect of CYP2C8 Inhibitors on Treprostinil Co-administration of Orenitram and the CYP2C8 enzyme inhibitor gemfibrozil in healthy adult volunteers increases exposure to treprostinil. Reduce the starting dose of Orenitram to 0.125 mg BID and use 0.125 mg BID increments not more frequently than every 3 to 4 days [see Dosage and Administration (2.4) and Clinical Pharmacology (12.3) ] .

8.1 Pregnancy Risk Summary Limited published data from case reports with Orenitram use in pregnant women are not sufficient to assess for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. There are risks to the mother and the fetus associated with pulmonary arterial hypertension (see Clinical Considerations ) . Animal reproductive studies with treprostinil diolamine administered orally have shown an adverse effect on the fetus.

In rats, administration of treprostinil to pregnant rats during the period of organogenesis at doses ≥10 mg/kg/day (approximately 15 times the human exposure at the dose of 3.5 mg BID on an AUC basis) resulted in decreased pregnancy rate, increased post-implantation loss, and decreased fetal viability and growth. In rabbits, teratogenicity and decreased fetal viability and growth were observed at doses ≥1.5 mg/kg/day (approximately 7 times the human exposure at the dose of 3.5 mg BID on an AUC basis) (see Animal Data ) . The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown.

All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Clinical Considerations Disease-associated maternal and embryo-fetal risk Pulmonary arterial hypertension in pregnancy increases the risk of maternal heart failure, stroke and death, preterm delivery, low birth weight, and stillbirth.

Data Animal Data In pregnant rats, reversible, dose-dependent decreases in body weight gain and food consumption were observed during the first four days of dosing in animals administered 10, 20, and 30 mg/kg/day treprostinil diolamine. In a dose range-finding study, there was a 17% decrease in the pregnancy rate in the animals administered 20 and 30 mg/kg/day. One dam in each of the 20 and 30 mg/kg/day had litters with no viable fetuses. In the definitive study (0, 5, 10, and 20 mg/kg/day), there were four treatment-related deaths, and a 32% decrease in the pregnancy rate for rats administered 20 mg/kg/day.

There was an 8% decrease in the pregnancy rate in the animals administered 10 mg/kg/day. Across both studies, an increase in post-implantation loss was observed in animals administered 10 to 30 mg/kg/day, and a significant decrease in the mean number of live births was seen at dose levels ≥10 mg/kg/day. The no observed adverse effect level was 5 mg/kg/day…