Late response to nalfurafine hydrochloride for pruritus in patients with chronic liver disease: a retrospective data analysis

Background: Nalfurafine hydrochloride is used for refractory pruritus; however, real-world data on its efficacy with long-term administration, particularly in late responders who initially failed treatment, are limited. We aimed to evaluate the efficacy of nalfurafine hydrochloride in patients with chronic liver disease and clarify the incidence and characteristics of late responders. Methods: A retrospective analysis of data of 210 patients who received nalfurafine hydrochloride for chronic liver disease-associated pruritus at our hospital since June 2015 was conducted. Efficacy at 12 weeks was evaluated in 76 patients for whom visual analog scale (VAS) assessment was possible. Results: Among all 76 patients, the VAS score significantly decreased from 55.2 before treatment to 30.0 after 12 weeks (P<0.001), resulting in an efficacy rate of 48.6%. The efficacy was generally consistent across analyses according to underlying liver disease and presence and stage of hepatocellular carcinoma. Of the 39 patients who were nonresponders at 12 weeks, 30 continued treatment until 48 weeks. Seven of these 30 (23%) patients experienced improvement in pruritus at 48 weeks and were defined as late responders. Conclusions: The study findings suggest the importance of considering continued treatment under careful follow-up, rather than discontinuing treatment based solely on initial response.