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

Inclusion Criteria: To be eligible for inclusion into the study, a patient must meet the following criteria:

1. Willing and able to provide written informed consent prior to participating in thisstudy;
2. Able to communicate clearly with the Investigator and staff, able to understand thestudy procedures, and able and willing to comply with the study schedules and allstudy requirements;
3. Males or females 18 years of age or older;
4. Currently on hemodialysis for end-stage renal disease and has been categorized asexperiencing moderate to severe uremic pruritus;
5. If female:
6. Is not of childbearing potential (surgically sterile or postmenopausal, asdefined in Section 6.5.1.6); or
7. Has a negative serum pregnancy test at screening and agrees to use acceptablecontraceptive measures (as defined in Section 6.5.1.6) from the time of informedconsent until the safety Follow-up Visit or 7 days after the last dose of studydrug, whichever is later.
8. If male, agrees not to donate sperm after the first dose of study drug until 7 daysafter the last dose, and agrees to use a condom with spermicide or abstain fromheterosexual intercourse during the study until 7 days after study drugadministration. (Note: No restrictions are required for a vasectomized male providedhis vasectomy was performed ≥4 months prior to dosing);
9. Has a dry body weight of ≥40.0 kg at screening (prescription target dry body weight);
10. Has adequacy of dialysis, defined as meeting 1 of the following criteria during the 3months prior to screening:
11. ≥2 single pool Kt/V measurements ≥1.2; or
12. ≥2 urea reduction ratio measurements ≥65%; or
13. 1 single pool Kt/V measurement ≥1.2 and 1 urea reduction ratio measurement ≥65%

Exclusion Criteria: A patient will be excluded from the study if any of the following criteria are met:

1. Received an investigational drugwithin 30 days prior to the first dose of study drug,or is planning to participate in another interventional clinical study while enrolledin this study.
2. Has a concomitant disease or any medical condition that, in the opinion of theInvestigator, could pose undue risk to the patient, impede completion of the studyprocedures, or would compromise the validity of the study measurements, including, butnot limited to:
3. Known or suspected history of Diagnostic and Statistical Manual of MentalDisorders, Fifth Edition, -diagnosed alcohol, narcotic or other drug abuse, orsubstance dependence within 12 months prior to screening;
4. New York Heart Association Class IV congestive heart failure (Appendix 1, Section 14.0);
5. Severe mental illness or cognitive impairment (eg, dementia);
6. Any other relevant acute or chronic medical or neuropsychiatric condition;