Study to Evaluate IV CR845 in Hemodialysis Patients With Moderate-to-Severe Pruritus

Inclusion Criteria: 1. Willing and able to provide written informed consent prior to participating in this study; 2. Able to communicate clearly with the Investigator and staff, able to read, complete questionnaires, and understand the study procedures; 3. Males or females 18 years of age or older; 4. ESRD patients who have been on hemodialysis 3 times per week for at least 3 months prior to the start of Screening; 5. Women of child-bearing potential must have a negative serum pregnancy test and agree to practice an acceptable form of birth control for the duration of the study 6. Male patients that are not biologically or surgically sterile must agree to practice an acceptable from of birth control for the duration of the study 7. Weigh between 88.2 lb (40.0 kg) and 297.6 lb (135.0 kg). 8. Patient must self-report pruritus in the month prior to screening. 9. If patient is receiving treatment for itch, this treatment must be stable prior to screening and during treatment period. 10. At least 2 single-pool Kt/V measurements ≥ 1.2, or at least 2 urea reduction ratio measurements ≥ 65%, or 1 single-pool Kt/V measurement ≥ 1.2 and 1 urea reduction ratio measurement ≥ 65% on different dialysis days during the 3 months period prior to Screening; 11. Patient who self-categorize as moderate-to-severe itch. Exclusion Criteria: 1. Known to be non-compliant with dialysis treatment (i.e., has missed more than 2 dialysis sessions in the past 2 months because of non-compliance); 2. Anticipated to receive a kidney transplant during the study; 3. Known history of allergic reaction to opiates, such as hives 4. Known or suspected history of alcohol, narcotic, or other drug abuse or dependence within 12 months prior to Screening; 5. Patient has any clinically relevant acute or chronic medical or neuropsychiatric condition which, in the opinion of the Investigator, would pose undue risk to the patient, would impede completion of the study procedures, or would compromise the validity of the study measurements; 6. Serum alanine aminotransferase or aspartate aminotransferase greater than 2.5 times the reference upper limit of normal (ULN), or total bilirubin greater than 2 times ULN at Screening; 7. Received another investigational drug within 30 days prior to the start of Screening or has planned to participate in another clinical trial while enrolled in this study; 8. Has pruritus probably or definitely attributed to a cause other than ESRD or its complications (e.g., patients with concomitant pruritic dermatological disease or cholestatic liver disease would be excluded). (Note: Patients whose pruritus is attributed to ESRD complications such as hyperparathyroidism, hyperphosphatemia, anemia, or the dialysis procedure or prescription may be enrolled); 9. Has localized itch restricted to the palms of the hands; 10. Has pruritus only during the dialysis session (by patient report); 11. Anticipated to receive opioid antagonists (e.g., naloxone, naltrexone), or opioid mixed agonist-antagonist (e.g., buprenorphine, nalbuphine) from the start of Screening through the end of the Treatment Period; 12. Used Salvia divinorum or Salvinorin A within 30 days prior to the start of Screening or is anticipated to use it during the study; 13. Received ultraviolet B treatment within 30 days prior to the start of Screening or anticipated to receive such treatment during the study; 14. Participated in a previous clinical trial with CR845.