Study to Evaluate the Pharmacokinetics and Metabolism of [14C] CR845 (Difelikefalin) in Patients With End Stage Renal Disease on Hemodialysis and in Healthy Subjects

Exclusion Criteria

• •Has a concomitant disease or any medical condition that, in the opinion of the Investigator, could pose undue risk to the patient, impede completion of the study procedures, or would compromise the validity of the study measurements, including, but not limited to:
• •* Known or suspected history of alcohol, narcotic, or other drug abuse, or substance dependence within 12 months prior to Screening;
• •* Significant systolic or diastolic heart failure (eg, New York Heart Association Class IV congestive heart failure \[Appendix 1\]);
• •* Severe mental illness or cognitive impairment (eg, dementia);
• •* Any other relevant acute or chronic medical or neuropsychiatric condition.
• •History of important drug or other allergy (except for untreated, asymptomatic seasonal allergies at time of dosing) unless deemed not clinically significant by the Investigator;
• •Use of any beverages and foods containing alcohol, quinine (tonic water), grapefruit, broccoli, Brussels sprouts, Seville oranges, pomegranate, star fruit, char-grilled meat, or caffeine/xanthine from 48 hours prior to dosing with study medication without evaluation and approval by the Investigator;
• •Use of any over-the-counter (OTC) medication (including nutritional or dietary supplements, herbal preparations, or vitamins, chapparal, comfrey, germander, gin bu huan, kava, pennyroyal, skullcap, St. John's Wort, or valerian) within 7 days prior to dosing with study medication;
• •Use of any new prescription medication from 14 days prior to dosing with study medication without evaluation and approval by the Investigator;
• •Has been treated with any known drugs that are moderate or strong inhibitors/inducers of cytochrome P450 (CYP) enzymes (e.g., barbiturates, phenothiazines, cimetidine, carbamazepine) within 30 days prior to dosing with study medication, and that, in the Investigator's judgment, may impact subject safety or the validity of the study results;
• •Positive results for human immunodeficiency virus (HIV) or hepatitis B surface antigen (HBsAg);
• •Is a healthy subject with positive results for hepatitis C virus (HCV) antibody at Screening. Note: Subjects with HD who test positive for HCV antibody may be allowed to enroll at the discretion of the Principal Investigator if their liver function tests are not otherwise clinically significant;
• •Has donated blood or has had an acute loss of blood (˃500 mL) during the 3 months prior to study drug administration;
• •Previous administration of any \[14C\] labeled drug substance within 1 year of study drug administration;
• •Has irregular bowel habits. "Irregular" being defined for the purpose of this study as NOT having a bowel movement at least every 2 days.)
• •Has been involved in an occupation that requires monitoring for radiation exposure (eg, X-ray technician);