Embryo-Fetal Toxicity

• Do not administer Letairis to a pregnant female because it may cause fetal harm. Letairis is very likely to produce serious birth defects if used by pregnant females, as this effect has been seen consistently when it is administered to animals [see Contraindications (4.1), Warnings and Precautions (5.1), and Use in Specific Populations (8.1)].

• Exclude pregnancy before the initiation of treatment with Letairis. Females of reproductive potential must use acceptable methods of contraception during treatment with Letairis and for one month after treatment. Obtain monthly pregnancy tests during treatment and 1 month after discontinuation of treatment [see Dosage and Administration (2.2) and Use in Specific Populations (8.6)].

• Because of the risk of embryo-fetal toxicity, females can only receive Letairis through a restricted program called the Letairis REMS program [see Warnings and Precautions (5.2)].