This is an intermediate-size patient population expanded access protocol for the use of intravenous (IV) difelikefalin for the treatment of moderate-to-severe pruritus associated with chronic kidney disease in adult patients undergoing hemodialysis.

Visits during the expanded access program will consist of a Baseline Visit to confirm eligibility and an End of Treatment visit. Patients will receive IV difelikefalin at a dose of 0.5 mcg/kg after each dialysis session, generally 3 times per week. The End of Treatment visit will be defined as the first dialysis visit following the last dose of IV difelikefalin under the intermediate-size patient population expanded access protocol.

Key Inclusion Criteria:

• Adults ≥ 18 years old;
• Has end-stage renal disease (ESRD) and is currently receiving in-center hemodialysis;
• Has moderate-to-severe pruritus attributed to ESRD which is significantly impacting the patient's quality of life;
• Has no comparable or satisfactory alternative therapy for the treatment of moderate-to-severe pruritus, as determined by the sponsor-investigator.

Key Exclusion Criteria:

• Has severe hepatic impairment (Child-Pugh class C), as the influence of severe hepatic impairment on the pharmacokinetics of difelikefalin has not been evaluated;
• Is pregnant or nursing;
• Has been exposed to any other investigational medication in the past 60 days;
• Present any other reason which may lead to an unfavorable risk-benefit ratio for treatment with difelikefalin, as determined by the sponsor-investigator;
• Has a known or suspected allergy to difelikefalin or any component of the investigational product.