CR845, a Kappa Opioid Receptor Agonist developed by Cara Therapeutics has been awarded Breakthrough Therapy Designation by the FDA for the treatment of Chronic Kidney Disease-Associated Pruritus in Hemodialysis Patients.
KOR agonists are already known to suppress itching and for example the selective KOR agonist nalfurafine (Remitch) is approved in Japan as a antipruritic since 2009.
Uremic pruritus is an intractable systemic itch condition that occurs with the greatest frequency and intensity in chronic kidney disease patients under hemodialysis and peritoneal dialysis. Aggregate, longitudinal, multi-country studies estimate the weighted prevalence of UP to be approximately 40% of patients with end-stage renal disease, with approximately 24 percent of patients reporting severe pruritus. Similarly, the majority of dialysis patients (approximately 60-70 percent) report pruritus, with 30 to 40 percent reporting moderate or severe pruritus.
The FDA based its decision on positive top-line results from the first part of a Phase 2/3 clinical trial of I.V. CR845 in patients with UP. The study met its primary endpoint, with a 68 percent reduction in worst itching scores versus placebo after an eight-week treatment period (p < 0.0019), and its secondary endpoint, with a 100 percent improvement in quality of life domains versus placebo (p < 0.0007). I.V. CR845 was well-tolerated in the trial.