Difelikefalin for pruritus associated with renal disease.

Chronic kidney disease-associated pruritus (CKD-aP) has been recognized for over a century. The complex pathophysiology of CKD-aP makes it challenging to find an effective treatment; the proposed therapeutic options come from anecdotal reports and small clinical trials, which at best compare the test drug against placebo. Gabapentinoids have shown relevant efficacy but there are serious safety concerns about their possible central nervous system toxicity. Recently difelikefalin, a κ-opioid receptor agonist, has been the first Food and Drug Administration (FDA)-approved drug for moderate-severe CKD-aP treatment. Approval from other regulatory agencies is expected in 2022. In this article, preclinical, pharmacokinetic and safety studies on difelikefalin are reported, but a great part of the data derive from meeting abstracts and non-peer-review communications and this is a possible cause for concern regarding bias in publication. A review of published and unpublished studies about difelikefalin in CKD-aP treatment is provided. Currently, two published large trials show that difelikefalin offers a new therapeutic opportunity to treat CKD-aP, a condition that leads to both worse survival and quality of life in hemodialysis patients.