Table 1 Eligibility criteria

Key inclusion criteria

Included patients had to meet all of the conditions listed below, all sexes and both inpatients and outpatients were eligible.

Upon obtaining informed consent

 1. A patient of age 20 years or older

 2. A patient undergoing peritoneal dialysis for three consecutive months or longer

 3. A patient with a history within 1 year of drug treatment (a) and (b) against itch

  (a) systemic treatment (oral, injection, etc.) for two consecutive weeks or longer using antihistamine or antiallergic drugs indicated for the treatment of itch

  (b) topical treatment (external, etc.) using ointment indicated for the treatment of itch or moisturizer prescribed by a physician

 4. A patient for whom neither of the treatment against itch listed in criteria 3 was evaluated sufficiently effective by the principal investigator or another investigator

Upon formal registration

 5. A patient undergoing peritoneal dialysis continuously from the date of informed consent to the date of formal registration

 6. A patient whose VAS score was recorded both on rising and before bed for five or more days in week 2 in pretreatment period, and the mean of the larger VAS score either upon rising or before bed was 50 mm or larger

 7. A patient of whom the larger VAS score either upon rising or before bed was 20 mm or larger for five or more days in week 2 of the pretreatment period

 8. A patient whose itch score based on Shiratori’s severity criteria was recorded both on rising and before bed for 5 days or more in week 2 in the pretreatment period, and the itch score either upon rising or before bed, whichever was score of 3 or higher (i.e., moderate or worse), for half of the days

Key exclusion criteria

Patients were excluded from the study if one or more of the following conditions applied.

Upon obtaining informed consent

 1. A patient who is concurrently undergoing hemodialysis

 2. A patient who has been clinically diagnosed with the following complications

  (a) encapsulating peritoneal sclerosis

  (b) atopic dermatitis, chronic urticarial, or other skin disease that was determined to develop a systemic itch symptom that affects the evaluation of itch induced by renal disease

 3. A patient who developed peritonitis within the last 4 weeks to make it difficult to continue peritoneal dialysis

 4. A patient who received a phototherapy against itch in the last 1 month

 5. A patient who has received nalfurafine in the past, who has participated in a clinical trial of nalfurafine and received it as the investigational drug, or who already participated as an eligible patient in this study

Upon formal registration

 6. A patient who underwent hemodialysis between the date of informed consent and the date of formal registration

 7. A patient who experienced onset of one of the following diseases between the date of informed consent and the date of formal registration

  (a) encapsulating peritoneal sclerosis

  (b) atopic dermatitis, chronic urticaria, or other skin disease that was determined to develop a systemic itch symptom that affects the evaluation of itch induced by renal disease

 8. A patient who developed peritonitis between the date of informed consent and the date of formal registration, which made it difficult to continue peritoneal dialysis

 9. A patient who received a phototherapy against itch between the date of informed consent and the date of formal registration