Opioid Withdrawal
In Studies 1, 2 and 3, adverse reactions consistent with opioid withdrawal were based on investigator assessment and adjudicated based upon the occurrence of at least 3 adverse reactions potentially related to opioid withdrawal with onset of a constellation of those symptoms occurring on the same day or within one day of each other.
Adverse reactions of possible opioid withdrawal could include non-gastrointestinal (GI) symptoms (e.g., hyperhidrosis, hot flush or flushing, chills, tremor, tachycardia, anxiety, agitation, yawning, rhinorrhea, increased lacrimation, sneezing, feeling cold, and pyrexia), GI symptoms (e.g., vomiting, diarrhea, or abdominal pain), or both GI and non-GI symptoms.
In pooled Studies 1 and 2, the incidence of adverse reactions of opioid withdrawal was 1% (8/542) for SYMPROIC and 1% (3/546) for placebo. In Study 3 (52-week data), the incidence was 3% (20/621) for SYMPROIC and 1% (9/619) for placebo. Most SYMPROIC treated subjects experienced nearly equal incidence of GI only or both GI and non-GI symptoms.
Less Common Adverse Reactions:
Two patients developed symptoms of hypersensitivity following a single dose of SYMPROIC. One patient reported bronchospasm and another rash.
Risk Summary
There are no available data with naldemedine in pregnant women to inform a drug-associated risk of major birth defects and miscarriage. There is a potential for opioid withdrawal in a fetus when SYMPROIC is used in pregnant women [see Clinical Considerations]. SYMPROIC should be used during pregnancy only if the potential benefit justifies the potential risk.
In a rat embryo-fetal development study following oral administration of naldemedine during the period of organogenesis at doses resulting in systemic exposure approximately 23,000 times the human area under the plasma-concentration time curve (AUC) at the recommended human dose of 0.2 mg/day, no developmental abnormalities were observed. In rabbits, there were no adverse effects on embryo-fetal development following oral administration of naldemedine during the period of organogenesis at doses resulting in systemic exposure approximately 226 times the human AUC at the recommended human dose of 0.2 mg/day [see Data]. No effects on pre- and postnatal development were observed in rats at exposures 12 times human exposures at the recommended human dose.
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. 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
Fetal/Neonatal Adverse Reactions
Naldemedine crosses the placenta, and may precipitate opioid withdrawal in a fetus due to the immature fetal blood-brain barrier.
Data
Animal Data
In rats, there were no adverse effects on embryo-fetal development following oral administration of naldemedine during the period of organogenesis at doses up to 1000 mg/kg/day (approximately 23,000 times the human exposures (AUC) at the recommended human dose). In rabbits, there were no adverse effects on embryo-fetal development following oral administration of naldemedine during the period of organogenesis at doses up to 100 mg/kg/day (approximately 226 times the human exposures (AUC) at the recommended human dose). At 400 mg/kg/day (approximately 844 times the human exposures (AUC) at the recommended human dose), effects in maternal animals included body weight loss/decreased body weight gain and food consumption, fetal loss, and premature delivery. Decreased fetal body weights at this dose may be related to the maternal toxicity observed.
In the pre- and postnatal development study, pregnant rats were administered naldemedine at oral doses up to 1000 mg/kg/day from gestation day 7 through lactation day 20. No effects on pre- and postnatal development were observed in rats at 1 mg/kg/day (approximately 12 times the human exposures (AUC) at the recommended human dose). A single dam died at parturition at 1000 mg/kg/day, and decreased body weights/body weight gain and food consumption, poor nursing, and total litter loss were noted at 30 and 1000 mg/kg/day (approximately 626 and 17,000 times the human exposures (AUC) at the recommended human dose, respectively). Decreases in the offspring viability index on Day 4 after birth were noted at 30 and 1000 mg/kg/day, and low body weights and delayed pinna unfolding in pups were noted at 1000 mg/kg/day.
Risk Summary
There is no information regarding the presence of naldemedine in human milk, the effects on the breastfed infant, or the effects on milk production. Naldemedine was present in the milk of rats [see Data]. Because of the potential for serious adverse reactions, including opioid withdrawal in breastfed infants, a decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother. If drug is discontinued in order to minimize drug exposure to a breastfed infant, advise women that breastfeeding may be resumed 3 days after the final dose of SYMPROIC.
Data
Drug-related radioactivity was transferred into milk of lactating rats following a single oral dose of 1 mg/kg [carbonyl-14C]-naldemedine.
Effect on Cardiac Repolarization
At a dose up to 5 times the recommended dose, SYMPROIC does not prolong the QT interval to any clinically relevant extent.
Absorption
Following oral administration, naldemedine is absorbed with a time to achieve peak concentrations (Tmax) of approximately 0.75 hours in a fasted state. Across the range of doses evaluated, the maximum plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) increased in a dose-proportional or almost dose-proportional manner. Accumulation was minimal following multiple daily doses of naldemedine.
Food Effect
A high-fat meal decreased the rate but not the extent of naldemedine absorption. The Cmax was decreased by approximately 35% and time to achieve Cmax was delayed from 0.75 hours in the fasted state to 2.5 hours in the fed state, whereas there was no meaningful change in the AUC in the fed state [see Dosage and Administration (2.2)].
Distribution
Plasma protein binding of naldemedine in humans is 93% to 94%. The mean apparent volume of distribution during the terminal phase (Vz/F) is 155 L.
Elimination
The terminal elimination half-life of naldemedine is 11 hours.
Metabolism
Naldemedine is primarily metabolized by CYP3A to nor-naldemedine, with minor contribution from UGT1A3 to form naldemedine 3-G. Nor-naldemedine and naldemedine 3-G have been shown to have antagonistic activity for opioid receptors, with less potent effect than naldemedine.
Following oral administration of [14C]-labeled naldemedine, the primary metabolite in plasma was nor-naldemedine, with a relative exposure compared to naldemedine of approximately 9% to 13%. Naldemedine 3-G was a minor metabolite in plasma, with a relative exposure to naldemedine of less than 3%.
Naldemedine also undergoes cleavage in the GI tract to form benzamidine and naldemedine carboxylic acid.
Excretion
Following oral administration of [14C]-labeled naldemedine, the total amount of radioactivity excreted in the urine and feces was 57% and 35% of the administered dose of naldemedine, respectively. The amount of naldemedine excreted unchanged in the urine was approximately 16% to 18% of the administered dose. Benzamidine was the most predominant metabolite excreted in the urine and feces, representing approximately 32% and 20% of the administered dose of naldemedine, respectively. The percentage of unchanged drug in feces has not been estimated.
Use in Specific Populations
Age: Geriatric Population, Sex, Race/Ethnicity
A population pharmacokinetic analysis from clinical studies with naldemedine did not identify a clinically meaningful effect of age, sex, or race on the pharmacokinetics of naldemedine.
Renal Impairment
The pharmacokinetics of naldemedine after administration of a 0.2 mg single oral dose of SYMPROIC was studied in subjects with mild (n=8, estimated glomerular filtration rate [eGFR] of 60 to 89 mL/min/1.73 m2), moderate (n=8, eGFR 30 to 59 mL/min/1.73 m2), and severe (n=6, eGFR less than 30 mL/min/1.73 m2) renal impairment, and subjects with end-stage renal disease (ESRD) requiring hemodialysis (n=8), and compared to healthy subjects with normal renal function (n=8, estimated creatinine clearance of at least 90 mL/min). The pharmacokinetics of naldemedine between subjects in all groups were similar.
Plasma concentrations of naldemedine in subjects with ESRD requiring hemodialysis were similar when SYMPROIC was administered either pre- or post-hemodialysis, indicating that naldemedine was not removed from the blood by hemodialysis.
Hepatic Impairment
The effect of hepatic impairment on the pharmacokinetics of a 0.2 mg single oral dose of SYMPROIC was studied in subjects with hepatic impairment classified as mild (n=8, Child-Pugh Class A) or moderate (n=8, Child-Pugh Class B) and compared with healthy subjects with normal hepatic function (n=8). The pharmacokinetics of naldemedine between subjects in all groups were similar.
The effect of severe hepatic impairment (Child-Pugh Class C) on the pharmacokinetics of naldemedine was not evaluated [see Use in Specific Populations (8.6)].
Drug Interaction Studies
Effect of Naldemedine on Other Drugs
In in vitro studies at clinically relevant concentrations, naldemedine did not inhibit the major CYP enzymes (including CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4/5, or CYP4A11 isozymes) and is not an inhibitor of transporters (including OATP1B1, OATP1B3, OCT1, OCT2, OAT1, OAT3, BCRP, or P-gp). Naldemedine did not cause significant induction of CYP1A2, CYP2B6, CYP3A4, UGT1A2, UGT1A6, or UGT2B7 isozymes.
Effect of Other Drugs on Naldemedine
Naldemedine is primarily metabolized by the CYP3A4 enzyme with a minor contribution from UGT1A3. Naldemedine is a substrate of P-gp. The effects of co-administered drugs on the pharmacokinetics of naldemedine are summarized in Figure 1.
Figure 1: Effect of Co-Administered Drugs on the Pharmacokinetics of Naldemedine
Efavirenz (moderate CYP3A inducer): Simulation using physiologically-based pharmacokinetic modeling suggested that concomitant use of efavirenz decreases exposure to naldemedine by 43%. The clinical consequence of this decreased exposure is unknown.
No drug interaction studies have been conducted for SYMPROIC with drugs that alter gastric pH (e.g., antacids, proton-pump inhibitors).
Carcinogenesis
In 2-year carcinogenicity studies, there were no drug-related neoplastic findings following oral administration of naldemedine to mice and rats at doses up to 100 mg/kg/day (approximately 17,500 and 6,300 times the human exposures (AUC) at the recommended human dose, respectively).
Mutagenesis
Naldemedine was not genotoxic in the in vitro bacterial reverse mutation (Ames) assay, a chromosomal aberration assay with cultured Chinese hamster lung cells, or an in vivo micronucleus assay with rat bone marrow cells.
Impairment of Fertility
Naldemedine was found to have no effect on fertility or reproductive performance in male and female rats at oral doses up to 1000 mg/kg/day (approximately 17,000 times the human exposures (AUC) at the recommended human dose). In female rats, prolongation of diestrous phase was noted at 10 mg/kg/day (approximately 179 times the human exposures (AUC) at the recommended human dose).
Administration
Advise patients to discontinue SYMPROIC if treatment with the opioid pain medication is also discontinued.
Gastrointestinal Perforation
Advise patients to discontinue SYMPROIC and to promptly seek medical attention if they develop unusually severe, persistent or worsening abdominal pain [see Warnings and Precautions (5.1)].
Opioid Withdrawal
Advise patients that clusters of symptoms consistent with opioid withdrawal may occur while taking SYMPROIC and to contact their healthcare provider if these symptoms occur [see Warnings and Precautions (5.2)].
Pregnancy
Advise females of reproductive potential, who become pregnant or are planning to become pregnant, that the use of SYMPROIC during pregnancy may precipitate opioid withdrawal in a fetus due to the undeveloped blood-brain barrier [see Use in Specific Populations (8.1)].
Lactation
Advise women that breastfeeding is not recommended during treatment with SYMPROIC and for 3 days after the final dose [see Use in Specific Populations (8.2)].
SYMPROIC is a registered trademark of Shionogi & Co., Ltd.
Manufactured for: BioDelivery Sciences International, Inc. Raleigh, NC 27612
SYM-001-PI-MAY2020