ide yellow, and iron oxide red). 12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Eluxadoline is a mu-opioid receptor agonist; eluxadoline is also a delta opioid receptor antagonist and a kappa opioid receptor agonist. The binding affinities (Ki) of eluxadoline for the human mu and delta opioid receptors are 1.8 nM and 430 nM, respectively. The binding affinity (Ki) of eluxadoline for the human kappa opioid receptor has not been determined; however, the Ki for guinea pig cerebellum kappa opioid receptor is 55 nM. In animals, eluxadoline interacts with opioid receptors in the gut. 12.2 Pharmacodynamics Cardiac Electrophysiology At a dose 10 times the maximum recommended dose (100 mg), VIBERZI does not prolong the QT interval to any clinically relevant extent. 12.3 Pharmacokinetics Following oral administration of 100 mg VIBERZI in healthy subjects, the Cmax of eluxadoline was approximately 2 to 4 ng/mL and AUC was 12 to 22 ng.h/mL. Eluxadoline has approximately linear pharmacokinetics with no accumulation upon repeated twice daily dosing. The variability of eluxadoline pharmacokinetic parameters ranges from 51% to 98%. Absorption Absolute bioavailability of eluxadoline has not been determined. The median Tmax value was 1.5 hours (range: 1 to 8 hours) under fed conditions and 2 hours (range: 0.5 to 6 hours) under fasting conditions. The administration of VIBERZI with a high fat meal that contained approximately 800 to 1000 total calories, with 50% of calories being derived from fat content decreased the Cmax of eluxadoline by 50% and AUC by 60%. Distribution Plasma protein binding of eluxadoline was 81%. Page 12 of 18 Reference ID: 3766744 Elimination The mean plasma elimination half-life of eluxadoline ranged from 3.7 hours to 6 hours. Metabolism Metabolism of eluxadoline is not clearly established [see Drug Interactions (7)]. There is evidence that glucuronidation can occur to form an acyl glucuronide metabolite. Excretion Following a single oral dose of 300 mg [14C] eluxadoline in healthy male subjects, 82.2% of the total radioactivity was recovered in feces within 336 hours and less than 1% was recovered in urine within 192 hours. Specific Populations Hepatic Impairment Following a single oral 100–mg dose in subjects with varying degrees of liver impairment and healthy subjects, mean eluxadoline plasma exposure was 6-fold, 4-fold, and 16-fold higher in mild, moderate, and severe hepatically impaired subjects (Child Pugh Class A, B, C), respectively, compared to the subjects with normal liver function [see Dosage and Administration (2), Contraindications (4), Use in Specific Populations (8.6)]. Drug Interactions In Vitro Assessment of Drug Interactions In vitro studies indicate that eluxadoline is neither an inducer of CYP1A2, CYP2C9, CYP2C19, and CYP3A4, nor an inhibitor of CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP3A4 and CYP2D6 at clinically relevant systemic concentrations. Although CYP2E1 was slightly inhibited by eluxadoline (IC50 of approximately 20 micromolar [11 mcg/mL]), clinically meaningful interactions are unlikely. The in vitro studies were not adequate to establish the potential for eluxadoline to inhibit CYP3A4 in the gut [see Drug Interactions (7)]. In vitro studies suggest that eluxadoline is a substrate for OAT3, OATP1B1, BSEP and MRP2, but not for OCT1, OCT2, OAT1, OATP1B3, P-gp and BCRP. Based on the in vitro studies, clinically meaningful interaction via inhibition of OCT1, OCT2, OAT1, OAT3, OATP1B3, BSEP and MRP2 by eluxadoline is unlikely. However, the in vitro studies were not adequate to establish the potential for eluxadoline to inhibit P-gp in the gut. In Vivo Assessment of Drug Interactions The following drug interactions were studied in healthy subjects: Page 13 of 18 Reference ID: 37667

USE IN SPECIFIC POPULATIONS Pregnancy Risk Summary There are no studies with VIBERZI in pregnant women that inform any drug-associated risks. The background risk of major birth defects and miscarriage for the indicated population is unknown. However, the background risk in the U.S. general population of major birth defects is 2 to 4% and of miscarriage is 15 to 20% of clinically recognized pregnancies. In animal reproduction studies, oral and subcutaneous administration of eluxadoline to rats and rabbits during organogenesis at doses approximately 51 and 115 times the human exposure after a single oral dose of 100 mg, respectively, demonstrated no teratogenic effects. In a pre- and postnatal development study in rats, no adverse effects were observed in offspring with oral administration of eluxadoline at doses approximately 10 times the human exposure [see Data]. Data Animal Data Eluxadoline administered as combined oral (1000 mg/kg/day) and subcutaneous (5 mg/kg/day) doses during the period of organogenesis to rats and rabbits (exposures about 51 and 115 times, respectively, the human AUC of 24 ng.h/mL after a single oral dose of 100 mg) did not cause any adverse effects on embryofetal development. A pre- and postnatal development study in rats showed no evidence of any adverse effect on pre- and postnatal development at oral doses of eluxadoline up to 1000 mg/kg/day (with exposures about 10 times the human AUC of 24 ng.h/mL after a single oral dose of 100 mg). In the same study, eluxadoline was detected in the Page 8 of 18 Reference ID: 3766744 milk of lactating rats administered oral doses of 100, 300 and 1000 mg/kg/day (with exposures about 1.8, 3 and 10 times, respectively, the human AUC of 24 ng.h/mL after a single oral dose of 100 mg). Milk samples were collected from six lactating females per group on lactation day 12. Mean concentrations of eluxadoline in the milk of lactating rats on lactation day 12 were 2.78, 5.49 and 44.02 ng/mL at 100, 300 and 1000 mg/kg/day, respectively. 8.2 Lactation Risk Summary No data are available regarding the presence of eluxadoline in human milk, the effects of eluxadoline on the breastfed infant, or the effects of eluxadoline on milk production. However, eluxadoline is present in rat milk [see Use in Specific Populations (8.1) ]. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for VIBERZI and any potential adverse effects on the breastfed infant from VIBERZI or from the underlying maternal condition. 8.4 Pediatric Use Safety and effectiveness in pediatric patients have not been established. Juvenile Toxicology Data Eluxadoline was orally administered to juvenile rats at 500, 750, and 1500 mg/kg/day (about 16, 54 and 30 times, respectively, the human AUC of 24 ng.h/mL after a single oral dose of 100 mg) for 4 weeks. There were no adverse physiologic effects related to eluxadoline. Based on these results, the NOAEL for male and female juvenile rats was 1500 mg/kg/day (about 30 times the human AUC of 24 ng.h/mL after a single oral dose of 100 mg). 8.5 Geriatric Use Of 1795 IBS-D patients in clinical trials of VIBERZI who received 75 mg or 100 mg twice daily, 139 (7.7%) were at least 65 years of age, while 15 (0.8%) were at least 75 years old. No overall differences in effectiveness were observed between these patients and younger patients. There were no overall differences in the types of adverse reactions observed between elderly and younger patients; however, a higher proportion of elderly patients than younger patients experienced adverse reactions (66% vs 59%), serious adverse reactions (9% vs 4%), and gastrointestinal adverse reactions (39% vs 28%). 8.6 Hepatic Impairment Plasma concentrations of eluxadoline increase in patients with hepatic impairment [see Clinical Pharmacology (12.3)]. Page 9 of 18 Reference ID: 3766744 VIBERZI is contraindicated in patients with severe hepatic impairment (Child-Pugh Class C) as plasma concentrations of eluxadoline increase significantly (16-fold) and there is no information to support the safety of VIBERZI in these patients. In patients with mild (Child-Pugh Class A) or moderate (Child-Pugh Class B) hepatic impairment, plasma concentrations of eluxadoline increase to a lesser extent (4- and 6-fold, respectively). Administer VIBERZI at a reduced dose of 75 mg twice daily to these patients [see Dosage and Administration (2)]. Monitor patients with any degree of hepatic impairment for impaired mental or physical abilities needed to perform potentially hazardous activities such as driving a car or operating machinery and for other eluxadoline-related adverse reactions [see Adverse Reactions (6.1)]. 9 9.1 Pending 9.2 DRUG ABUSE AND DEPENDENCE Controlled Substance Abuse In a drug discri