Fedratinib

7 DRUG INTERACTIONS • Strong CYP3A4 Inhibitors: Reduce INREBIC dose as recommended ( 2.3 , 7.1 ). • Strong and Moderate CYP3A4 Inducers: Avoid use of INREBIC ( 7.1 ). • CYP3A4, CYP2C19, or CYP2D6 Substrates: Dose modifications of substrates drugs may be needed ( 7.2 ). • OCT2 and MATE1/2-K Substrates: Dose modifications of substrate drugs may be needed ( 7.2 ).

7.1 Effect of Other Drugs on INREBIC Strong CYP3A4 Inhibitors Coadministration of INREBIC with a strong CYP3A4 inhibitor increases fedratinib exposure [see Clinical Pharmacology (12.3) ] . Increased exposure may increase the risk of adverse reactions. Consider alternative therapies that do not strongly inhibit CYP3A4 activity. Alternatively, reduce the dose of INREBIC when administering with a strong CYP3A4 inhibitor [see Dosage and Administration (2.4) ] . Strong and Moderate CYP3A4 Inducers Coadministration of INREBIC with a strong or moderate CYP3A4 inducer can decrease fedratinib exposure [see Clinical Pharmacology (12.3) ] . Decreased exposure may reduce the effectiveness of INREBIC.

Avoid INREBIC with strong and moderate CYP3A4 inducers. Dual CYP3A4 and CYP2C19 Inhibitors Coadministration of INREBIC with a dual CYP3A4 and CYP2C19 inhibitor increases fedratinib exposure [see Clinical Pharmacology (12.3) ] . Increased exposure may increase the risk of adverse reactions. Due to potential increase of exposure, patients taking concomitant dual CYP3A4 and CYP2C19 inhibitors require more intensive safety monitoring and, if necessary, dose modifications of INREBIC based on adverse reactions [see Dosage and Administration (2.6) ] .

7.2 Effect of INREBIC on Other Drugs CYP3A4, CYP2C19, or CYP2D6 Substrate Drugs Coadministration of INREBIC with drugs that are CYP3A4 substrates, CYP2C19 substrates, or CYP2D6 substrates increases the concentrations of these drugs, which may increase the risk of adverse reactions of these drugs [see Clinical Pharmacology (12.3) ] . Monitor for adverse reactions and adjust the dose of drugs that are CYP3A4, CYP2C19, or CYP2D6 substrates as necessary when coadministered with INREBIC.

OCT2 and MATE1/2-K Substrate Drugs Coadministration of INREBIC with drugs that are renally excreted via organic cation transporter (OCT2) and multidrug and toxin extrusion (MATE)1/2-K can decrease renal clearance of those drugs [see Clinical Pharmacology (12.3) ] . Monitor for adverse reactions and consider dose modifications for drugs that are renally excreted via OCT2 or MATE1/2-K (e.g., metformin), as necessary when coadministered with INREBIC.

8.1 Pregnancy Risk Summary There are no available data on INREBIC use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. In animal reproduction studies, oral administration of fedratinib to pregnant rats during organogenesis at doses considerably lower than the recommended human daily dose of 400 mg/day resulted in adverse developmental outcomes (see Data ) . Consider the benefits and risks of INREBIC for the mother and possible risks to the fetus when prescribing INREBIC to a pregnant woman. The background risk of major birth defects and miscarriage for the indicated population is unknown.

Adverse outcomes in pregnancy occur regardless of the health of the mother or the use of medications. 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. Data Animal Data In an embryo-fetal development study in pregnant rats, fedratinib administration at a dose of 30 mg/kg/day during organogenesis (gestation days 6 to 17) was associated with adverse developmental outcomes including skeletal variations (such as additional ossification center of neuronal arches).

These effects occurred in rats at approximately 0.1 times the clinical exposure based on AUC at the recommended daily dose. At lower doses of 10 mg/kg/day (0.01 times the clinical exposure at the recommended daily dose), fedratinib administered to pregnant rats resulted in maternal toxicity of decreased gestational weight gain. In an embryo-fetal development study in pregnant rabbits, fedratinib administration during organogenesis (gestation Days 6 to 18) did not produce developmental or maternal toxicity at doses up to the highest dose level tested, 30 mg/kg/day (approximately 0.08 times the clinical exposure at the recommended daily dose).

In a separate study, administration of 80 mg/kg/day fedratinib to rabbits resulted in maternal mortality. In a pre- and postnatal study in rats, fedratinib was administered to pregnant female rats at doses of 3, 10, or 30 mg/kg/day from Day 6 of gestation through Day 20 of lactation, with weaning on Day 21. A slight decrease in maternal body weight gain during gestation occurred at 30 mg/kg/day. The offspring from the high dose (30 mg/kg) had decreased body weight preweaning in both sexes and postweaning through the maturation phase in males. These effects occurred at exposures approximately 0.1 times the clinical exposure at the recommended daily dose.