Pacritinib

Co-administration of VONJO with moderate CYP3A4 inhibitors can increase the exposure to pacritinib. Monitor for increased adverse reactions of VONJO when administered with moderate CYP3A4 inhibitors ( 7.1 ). VONJO is an inhibitor of P-gp, BCRP, and CYP1A2 and an inducer of CYP3A4 and CYP2C19. Monitor patients concomitantly receiving substrates of these transporters and enzymes, and adjust dose of the substrates as needed ( 7.2 ). VONJO may reduce the effectiveness of hormonal contraceptives ( 7.2 )

7.1 Effect of Other Drugs on VONJO Strong and Moderate CYP3A4 Inhibitors Pacritinib is predominantly metabolized by CYP3A4. Concomitant use of VONJO with strong and moderate CYP3A4 inhibitors increases pacritinib exposure, which may increase the risk of exposure-related adverse reactions [see Clinical Pharmacology ( 12.3 )] Co-administration of VONJO with strong CYP3A4 inhibitors is contraindicated [see Contraindications ( 4 )]. Monitor patients concomitantly receiving moderate CYP3A4 inhibitors (e.g., fluconazole) for increased adverse reactions and consider VONJO dose modifications based on safety [see Dosage and Administration ( 2.5 )] .

Concomitant use of VONJO with doses of fluconazole greater than 200 mg once daily has not been studied. Strong CYP3A4 Inducers Pacritinib is predominantly metabolized by CYP3A4. Concomitant use of VONJO with strong CYP3A4 inducers decreases pacritinib exposure, which may reduce efficacy of VONJO [see Clinical Pharmacology ( 12.3 )] . Co-administration of VONJO with strong CYP3A4 inducers is contraindicated [see Contraindications ( 4 )].

7.2 Effect of VONJO on Other Drugs CYP1A2 Substrates Pacritinib is an inhibitor of CYP1A2. VONJO increases the plasma concentrations of CYP1A2 substrates [see Clinical Pharmacology ( 12.3 )] ,which may increase the risk of adverse reactions from the CYP1A2 substrate. Monitor for CYP1A2 substrate related adverse reactions more frequently, unless otherwise recommended in the substrate Prescribing Information, when VONJO is used concomitantly with CYP1A2 substrates where minimal substrate concentration changes may lead to serious adverse reactions. CYP2C19 Substrates Pacritinib is an inducer of CYP2C19.

VONJO decreases the plasma concentrations of CYP2C19 substrates [see Clinical Pharmacology ( 12.3 )] , which may decrease the efficacy from the CYP2C19 substrate. Monitor the efficacy of CYP2C19 substrate more frequently, unless otherwise recommended in the substrate Prescribing Information, when VONJO is used concomitantly with CYP2C19 substrates where minimal substrate concentration changes may lead to diminished efficacy. Dose adjustment of CYP2C19 substrates may be needed. CYP3A4 Substrates Pacritinib is an inducer of CYP3A4. VONJO decreases the plasma concentrations of CYP3A4 substrates [see Clinical Pharmacology ( 12.3 )] , which may decrease the efficacy from the CYP3A4 substrate.

Monitor the efficacy of CYP3A4 substrate more frequently, unless otherwise recommended in the substrate Prescribing Information, when VONJO is used concomitantly with CYP3A4 substrates where minimal substrate concentration changes may lead to diminished efficacy. Dose adjustment of CYP3A4 substrates may be needed. Hormonal Contraceptives Avoid concomitant use of VONJO with hormonal contraceptives except for intrauterine systems containing levonorgestrel. The effectiveness of hormonal contraceptives, except for intrauterine systems containing levonorgestrel, may be reduced when used with VONJO.

If contraception is needed or desired, an alternate contraceptive that is not affected by CYP3A4 inducers (e.g., an intrauterine system) or additional nonhormonal contraceptive (e.g., condoms) should be used when treated concomitantly with VONJO, and for 30 days after last dose of VONJO. P-gp Substrates Pacritinib is an inhibitor of P-gp. VONJO increases the plasma concentrations of P-gp substrates [see Clinical Pharmacology ( 12.3 )] , which may increase the risk of adverse reactions from the P-gp substrate.

Monitor for P-gp substrate related adverse reactions more frequently, unless otherwise recommended in the substrate Prescribing Information, when VONJO is used concomitantly with P-gp substrates where minimal substrate concentration changes may lead to serious adverse reactions. Digoxin: Measure serum digoxin concentrations before initiating concomitant use with VONJO and continue monitoring serum digoxin concentrations as recommended in the Prescribing Information for digoxin [see Clinical Pharmacology ( 12.3 )] . BCRP substrates Pacritinib is an inhibitor of BCRP.

VONJO increases the plasma concentrations of BCRP substrates [see Clinical Pharmacology ( 12.3 )] , which may increase the risk of adverse reactions from the BCRP substrate. When used concomitantly with VONJO, monitor for BCRP substrate related adverse reactions more frequently and consider dose reduction of the BCRP substrate according to its Prescribing Information. Rosuvastatin: The dose of rosuvastatin should not exceed 20 mg once daily when concomitantly used with VONJO [see Clinical Pharmacology ( 12.3 )] .

8.1 Pregnancy Risk Summary There are no available data on VONJO 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, administration of pacritinib to pregnant mice or rabbits at exposures that were considerably lower than those observed at the recommended human dose were associated with maternal toxicity and embryonic and fetal loss (see Data ) . Advise pregnant women of the potential risk to a fetus. Consider the benefits and risks of VONJO for the mother and possible risks to the fetus when prescribing VONJO to a pregnant woman.

The estimated background risk of major birth defects and miscarriage for the indicated population(s) 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. Data Animal Data Pacritinib was administered orally to pregnant mice at doses of 30, 100, or 250 mg/kg/day from gestation day 6 to gestation day 15. Pacritinib was also administered orally to pregnant rabbits at doses of 15, 30, or 60 mg/kg/day from gestation day 7 until gestation day 20.

In both species, pacritinib was associated with maternal toxicity, which resulted in post-implantation loss in mice, abortions in rabbits, and reduced fetal body weights in mice and rabbits at exposures 0.1 times (mice) and 0.3 times (rabbits) the exposure at the recommended human dose (AUC-based). In mice, the high dose was associated with an increased incidence of an external malformation (cleft palate) in the presence of maternal toxicity. In a pre- and post-natal development study in mice, pregnant animals were dosed with pacritinib from implantation through lactation at 30, 100, or 250 mg/kg/day.

Maternal toxicity was noted at 250 mg/kg and associated with increased gestation length and dystocia, lowered mean birth weights and neonatal survival, and transiently delayed startle response, learning, and memory development at weaning.