Study to Evaluate the Efficacy and Safety of Oral Difelikefalin (CR845) for Moderate to Severe Pruritus in Subjects With Notalgia Paresthetica (KOMFORT)

The study will consist of a 37-day Screening period, a 7-day Run-In period, a 8-week Placebo-Controlled Treatment period followed by a 4-week Active Extension period and a Follow Up visit approximately 14 days after the last dose of study drug. All subjects will sign an informed consent form (ICF) and undergo screening for study eligibility. Subjects will be randomized to receive either placebo or difelikefalin (CR845) tablets at a dose of 2.0 mg, orally BID. Intake of the first dose of study drug will be at Day 1. Subjects who complete the Placebo-Controlled Treatment period of the study will transition into the Active Extension period upon completion of the Week 8 visit assessments. All subjects in the Active Extension will receive difelikefalin (CR845).