Narrow Therapeutic Index Drugs (Thioridazine and Pimozide)
VARUBI is contraindicated in patients taking CYP2D6 substrates with a narrow therapeutic index such as thioridazine and pimozide. Increased plasma concentrations of thioridazine and pimozide are associated with serious and/or life-threatening events of QT prolongation and Torsades de Pointes [see Contraindications (4)].
Before starting treatment with VARUBI, consider whether patients require treatment with thioridazine or pimozide. If patients require these drugs, use an alternative antiemetic to VARUBI or an alternative to thioridazine or pimozide that is not metabolized by CYP2D6.
Other Drugs
VARUBI can also increase plasma concentrations of other CYP2D6 substrates for at least 28 days following administration of VARUBI and may result in adverse reactions.
Before starting treatment with VARUBI, consult the prescribing information for CYP2D6 substrates to obtain additional information about interactions with CYP2D6 inhibitors.
Risk Summary
The limited data with VARUBI use in pregnant women are insufficient to inform a drug associated risk of adverse developmental outcomes. In animal reproduction studies, there were no adverse developmental effects observed with oral administration of rolapitant in rats and rabbits during the period of organogenesis at doses up to 1.2 times and 2.9-times, respectively, the maximum recommended human dose (MRHD) (see Data).
The estimated background risk of major birth defects and miscarriage for the indicated population 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
The potential embryo-fetal toxicity of rolapitant was assessed in pregnant rats administered oral doses up to 22.5 mg/kg per day throughout the period of organogenesis. Rats administered doses of 13.5 or 22.5 mg/kg per day rolapitant exhibited evidence of maternal toxicity including decreased body weight gain and/or body weight loss and a concomitant decrease in food consumption during the first week of dosing. No adverse embryo-fetal developmental effects were observed at doses up to 22.5 mg/kg per day rolapitant (approximately 1.2 times the recommended human dose on a body surface area basis). In rabbits administered rolapitant throughout the period of organogenesis, oral doses up to 27 mg/kg per day (approximately 2.9 times the recommended human dose on a body surface area basis) were without effects on the developing fetus.
The pre- and postnatal developmental effects of rolapitant were assessed in rats administered oral doses of 2.25, 9 or 22.5 mg/kg per day during the periods of organogenesis and lactation. Maternal toxicity was evident based on mortality/moribund condition, decreased body weight and food consumption, total litter loss, prolonged parturition, decreased length of gestation, and increased number of unaccounted for implantation sites at a dose of 22.5 mg/kg per day (approximately 1.2 times the recommended human dose on a body surface area basis). Effects on offspring at this dose included decreased postnatal survival, and decreased body weights and body weight gain, and may be related to the maternal toxicity observed. At a maternal dose of 9 mg/kg per day rolapitant (approximately 0.5 times the recommended human dose on a body surface area basis), there was a decrease in memory in female pups in a maze test and a decrease in pup body weight.
Risk Summary
There are no data on the presence of rolapitant in human milk, the effects of rolapitant in the breastfed infant, or the effects of rolapitant on milk production. Rolapitant administered orally to lactating female rats was present in milk (see Data). The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for VARUBI and any potential adverse effects on the breastfed infant from VARUBI or from the underlying maternal condition or the use of concomitant chemotherapy.
Data
Radioactivity from labeled [14C] rolapitant was transferred into milk of lactating rats following a single oral dose of 22.5 mg/kg, and the maximum radioactivity in milk was observed at 12 hours post-dose. The mean milk/plasma radioactivity concentration ratios in dams at 1 to 48 hours post-dose ranged from 1.24 to 3.25. Based on average daily consumption of milk (2 mL/day) and the maximum milk radioactivity determined, pup exposure is expected to be 0.3% of the orally administered dose.
Infertility
Females
In animal fertility studies, rolapitant impaired the fertility in females in a reversible fashion [see Nonclinical Toxicology (13.1)].
Juvenile Animal Toxicity Data
A toxicity study in juvenile rats at rolapitant doses approximately 1.2 and 2.5 times the approved adult body surface area (BSA)-based dose from postnatal day (PND) 7 through PND 70 (approximate human age equivalent of birth to 16 years) identified reproductive toxicity. A subsequent toxicity study in juvenile rats was conducted to identify the critical window of exposure for reproductive toxicity. A rolapitant dose of 50 mg/kg/day (approximately 2.7 times the approved adult BSA-based dose) was administered daily from PNDs 7 through 70, 7 to 21, 21 to 42 and 42 to 70 (approximate human age equivalent of birth to 16 years, birth to 2 years, 2 years to 12 years, and 12 years to 16 years, respectively). Female juvenile rats treated with rolapitant beginning on PND 7 developed adverse effects including partial or irreversible lower uterine weights that correlated with decreased endometrial glands of the uterus, decreases in the numbers of corpora lutea, implantation sites and live embryos and increases in pre- and post-implantation loss, and early resorptions. These adverse effects were observed in female juvenile rats administered rolapitant prior to PND 21 (approximate human age equivalent of 2 years). Additionally, juvenile rats treated with rolapitant beginning on either PND 7 or PND 21 developed slight changes in the onset of sexual maturation (including earlier attainment of vaginal opening in females and delay in preputial separation in males).
NK1 Receptor Occupancy
A human Positron Emission Tomography (PET) study with rolapitant demonstrated that rolapitant crosses the blood brain barrier and occupies brain NK1 receptors. A dose-dependent increase in mean NK1 receptor occupancy was observed in the oral dose range from 4.5 mg to 180 mg of rolapitant. At the 180 mg oral dose of rolapitant, the mean NK1 receptor occupancy was 73% in the striatum at 120 hours after a single dose administration in healthy subjects. The relationship between NK1 receptor occupancy and the clinical efficacy of rolapitant has not been established.
Cardiac Electrophysiology
At an oral dose of 720 mg (4 times the recommended oral dose), VARUBI does not prolong the QT interval to any clinically relevant extent.
Absorption
Following a single oral dose administration of 180 mg VARUBI under fasting conditions to healthy subjects, rolapitant was measurable in plasma within 30 minutes and the peak plasma concentration (Cmax) for rolapitant which was reached in about 4 hours and mean Cmax was 968 ng/mL (%CV:28%).
Following multiple oral doses of 9 to 45 mg once daily of rolapitant (5% to 25% of the recommended dose) for 10 days, accumulation of rolapitant (ratio of AUC0-24hr) ranged from 5.0 to 5.3 fold.
The systemic exposures (Cmax and AUC) to rolapitant increased in a dose-proportional manner when single oral doses of rolapitant increased from 4.5 mg to 180 mg. With 4 times the recommended clinical oral dose of 180 mg, the Cmax and AUC of rolapitant increased 3.1 fold and 3.7 fold, respectively.
Concomitant administration of a high-fat meal did not significantly affect the pharmacokinetics of rolapitant after administration of 180 mg VARUBI [see Dosage and Administration (2)].
Distribution
Rolapitant was highly protein bound to human plasma (99.8%). The apparent volume of distribution (Vd/F) following a single oral dose of 180 mg rolapitant was 460 L in healthy subjects. The large Vd indicated an extensive tissue distribution of rolapitant. In a population pharmacokinetic analysis of oral rolapitant, the Vd/F was 387 L in cancer patients.
Elimination
Following single oral doses (4.5 to 180 mg) of rolapitant, the mean terminal half-life (t1/2) of rolapitant ranged from 169 to 183 hours (approximately 7 days), and was independent of dose. In a population pharmacokinetic analysis, the apparent total clearance (CL/F) of oral rolapitant was 0.96 L/hour in cancer patients.
Metabolism
Rolapitant is metabolized primarily by CYP3A4 to form a major active metabolite, M19 (C4-pyrrolidine-hydroxylated rolapitant). In a mass balance study, the metabolite M19 was determined to be the major circulating metabolite. The rate of formation of M19 was relatively slow, resulting in the delayed median Tmax of 120 hours (range: 24 to 168 hours) with Cmax of 183 ng/mL. The mean half-life of M19 was 158 hours.
The exposure ratio of M19 to rolapitant was approximately 50% in plasma.
Excretion
Rolapitant is eliminated primarily through the hepato/biliary route. Following administration of a single oral 180-mg dose of [14C]-rolapitant, on average 14.2% (range 9% to 20%) and 73% (range 52% to 89%) of the dose was recovered in the urine and feces, respectively over 6 weeks. In pooled samples collected over 2 weeks, 8.3% of the dose was recovered in the urine primarily as metabolites and 37.8% of the dose was recovered in the feces primarily as unchanged rolapitant. Unchanged rolapitant or M19 was not found in pooled urine sample.
Specific Populations
Age, Male and Female Patients and Racial or Ethnic Groups
Population pharmacokinetic analyses indicated that age, sex and race had no significant impact on the pharmacokinetics of rolapitant.
Patients with Hepatic Impairment
Following administration of a single oral dose of 180 mg rolapitant to patients with mild hepatic impairment (Child-Pugh Class A), the pharmacokinetics of rolapitant were comparable with those of healthy subjects. In patients with moderate hepatic impairment (Child-Pugh Class B), the mean Cmax was 25% lower while mean AUC of rolapitant was similar compared to those of healthy subjects. The median Tmax for M19 was delayed to 204 hours in patients with mild or moderate hepatic impairment compared to 168 hours in healthy subjects. The pharmacokinetics of rolapitant were not studied in patients with severe hepatic impairment (Child-Pugh Class C) [see Use in Specific Populations (8.6)].
Patients with Renal Impairment
In population pharmacokinetic analyses, rolapitant pharmacokinetics in cancer patients with mild (CLcr: 60 to 90 mL/min) or moderate (CLcr: 30 to 60 mL/min) renal impairment was comparable to cancer patients with normal kidney function. Information is insufficient for the effect of severe renal impairment. The pharmacokinetics of rolapitant was not studied in patients with end-stage renal disease requiring hemodialysis.
Drug Interaction Studies
Effect of Other Drugs on Rolapitant
Rolapitant is a substrate for CYP3A4.