<qa>  What is the name of the kappa-opioid receptor agonist developedNalfurafine hydrochloride is a selective kappa-opioid receptor agonist developed in Japan, and in January 2009 approved for pruritus in patients with renal failure and under hemodialysis. A phase 3 trial of nalfurafine hydrochloride for pruritus in patients with chronic liver diseases was completed, indicating the efficacy as well as safety was confirmed. Therefore, in May 2015 the use of nalfurafine hydrochloride was officially approved in Japan for pruritus in patients with chronic liver diseases including PBC. However, only 59 patients with PBC were included and therefore it is still unclear whether nalfurafine chloride is effective in all PBC patients or a part of them, whether the effect of this drug depends on coadministered drugs or other complications, or whether this drug may improve QOL overall in patients with PBC. 