Notalgia paresthetica (NP) is a common, underdiagnosed condition that feels like an intense itching, burning, prickly (pins-and-needles) sensation between the shoulder blades or upper spine. Signs and symptoms of notalgia paraesthetica in the affected area may also include:

• Darker or lighter patches of skin (usually between the size of a golf ball and a grapefruit)
• Scratch marks or scarring
• Thick or leathery skin

We are currently recruiting subjects aged 18 years and older with moderate to severe itch due to Notalgia Paresthetica (NP) to participate in an investigational trial. The primary purpose of this research is to evaluate the safety and effectiveness of an oral (taken by mouth) investigational drug called Difelikefalin in participants with NP.

The study consists of taking an oral study treatment twice daily. You will have a 3 out of 4 (75%) chance of receiving the investigational treatment rather than placebo (pill that does not contain any treatment) for the 8 weeks of treatment. After the 8 weeks, there is a 2-week discontinuation period where you will have stopped taking the treatment. You will have a total of 7 in-person visits.

Participation will last approximately 15 weeks, including up to 4-weeks for screening and a 2-week post-treatment follow-up visit. Visits take approximately 30 minutes to 2.5 hours each, except for the screening visit which may take up to 3 hours.

Blood samples will be collected from all participants at Screening, Day 1, week 2, week 4, week 8, and the safety follow-up visit.

An electrocardiogram to check heart health will be taken at visit 1 and again at visit 6.

Compensation for time and travel may be available. There will be no cost to you for taking part in this study. You will be provided with all study medication, examinations and medical care related to the study at no cost to you.