Clinical Study on the Efficacy and Safety of Nalfurafine Hydrochloride Orally Disintegrating Tablets in Treating Pruritus in Patients Undergoing Maintenance Hemodialysis

• Nalfurafine Hydrochloride (Drug): Nalfurafine hydrochloride orally disintegrating tablets will be took at a dose of 2.5μg (1 tablet) once daily for 12 consecutive weeks.
• Basic treatment (Other): If any itching treatment medication is being received on the day of the screening period, the itching treatment medication (prescription drugs, over-the-counter drugs, moisturizers, etc. with itching as the indication, see the allowed medication list for details) will continue to be used as the basic treatment during the subsequent itching evaluation period. If no itching treatment medication is received by the start of the screening period, no other itching treatment medication will be used as the baseline treatment during the itch evaluation period of the study.

Primary outcomes

• Change in Visual Analogue Scale (VAS) from baseline [Change from baseline at 12 weeks]: Visual Analog Scale (VAS) is a scale that allows patients to indicate their level of itching on a 10cm scale. The larger the value, the higher the level of itching

Secondary outcomes

• Change in average VAS value from baseline across each evaluation period [Changes from baseline at weeks 1, 2, 4, 8, 12 of drug administration and during the follow-up period (1 week after the end of drug administration)]: Visual Analog Scale (VAS) is a scale that allows patients to indicate their level of itching on a 10cm scale. The larger the value, the higher the level of itching
• Change in itch score based on the Xie-Kawashima Itch Severity Assessment compared to baseline [Change from baseline at 12 weeks]: Xie-Kawashima Itch Severity Assessment evaluates the severity of itching, scratching behavior, and impact on sleep in patients during both daytime and nighttime. The total score is 0-10 points, with 0-4 points indicating "almost no itching" to "unbearable itching", 4-7 points indicating moderate itching, and 7-10 points indicating severe itching.
• The change in itch score from baseline for the Xie-Kawashima Itch Severity Assessment during each evaluation period [Changes from baseline at weeks 1, 2, 4, 8, 12 of drug administration and during the follow-up period (1 week after the end of drug administration)]: Xie-Kawashima Itch Severity Assessment evaluates the severity of itching, scratching behavior, and impact on sleep in patients during both daytime and nighttime. The total score is 0-10 points, with 0-4 points indicating "almost no itching" to "unbearable itching", 4-7 points indicating moderate itching, and 7-10 points indicating severe itching.
• Improvement degree of VAS [Change from baseline at 12 weeks]: Visual Analog Scale (VAS) is a scale that allows patients to indicate their level of itching on a 10cm scale. The larger the value, the higher the level of itching
• Skin Disease Quality of Life Scale (Skindrex-16) [Change from baseline at 12 weeks]: The Skindex-16 test evaluates the impact of skin diseases on a patient's quality of life by measuring symptoms, emotions, and functional limitations on a scale from 0 to 100. Scores are calculated by averaging responses across all items, where higher values indicate greater impairment. Reference ranges typically categorize scores as mild (<30), moderate (30-60), or severe (>60) effect on quality of life.
• Improved sleep quality [Change from baseline at 12 weeks]: Applying the Pittsburgh Sleep Quality Index to Evaluate Sleep Quality The Pittsburgh Sleep Quality Index (PSQI) consists of 9 items, and A and sleep quality are calculated according to the scoring method; B、 Sleep time; C、 Sleep duration; D、 Sleep efficiency; E、 Sleep disorders; F、 Hypnosis drugs; G、 Daytime functional impairment score, and then obtain PSQI total score=A+B+C+D+E+F+G 0-5 points. Good sleep quality 6-10 points. Sleep quality is okay 11-15 points, average sleep quality 16-21 points. Poor sleep quality Calculate baseline and post medication score changes.
• Serum endorphin levels [Change from baseline at day 29, day 57, and day 85.]: Blood samples were collected from patients before hemodialysis on day 0, day 29, day 57, and day 85. Measure the concentration of endorphins in the serum based on the collected blood samples from the subjects.
• Serum dynorphin levels [Change from baseline at day 29, day 57, and day 85.]: Blood samples were collected from patients before hemodialysis on day 0, day 29, day 57, and day 85. Measure the concentration of dynorphins in the serum based on the collected blood samples from the subjects.
• Kidney Disease Quality of Life Scale (KDQOL-36) [Change from baseline at 12 weeks]: The Kidney Disease Quality of Life Scale (KDQOL-36) evaluates the quality of life of patients with kidney disease, consisting of 36 questions covering multiple aspects such as physiology, psychology, and society.The scores for each dimension of the KDQOL-36 scale are usually expressed as 0-100 points, with higher scores indicating better quality of life.

Other outcomes

• Adverse events and serious adverse events [Within 12 weeks of taking nalfurafine hydrochloride]

Sex: All, ages: 18 Years to 80 Years

Inclusion Criteria:

* Age range of 18-80 years old (including both ends), male or female not limited.
* Chronic renal failure patients who undergo stable dialysis for 3 months or more, receive regular hemodialysis 3 times a week, and are expected to have no significant changes in treatment or rapid changes in their condition during the clinical trial period.
* Within one year prior to signing the informed consent form, the effectiveness of itch treatment (including topical medications such as moisturizers/moisturizers, systemic medications such as antihistamines or antiepileptic drugs, and non pharmacological treatments) was not satisfactory.
* Those who are able to understand and comply with the research procedures and methods, voluntarily participate in this study, and sign a written informed consent form.
* The number of days during which VAS values are measured at both wake-up and bedtime in the baseline period must be no less than 5 days, and the average value of the larger VAS values in morning and evening measurements must not be less than 50 mm.
* The number of days evaluated for the severity of itching in Xie Chuandao during the baseline period must be no less than 5 days at both wake-up and bedtime.

Exclusion Criteria:

* Given poor compliance with dialysis treatment, researchers believe that it may affect the effectiveness and safety of clinical studies.
* Patients who plan to undergo kidney transplantation or other elective surgeries during the study period.
* Patients with alanine aminotransferase (ALT), aspartate aminotransferase (AST), or glutamine transferase (GGT) levels exceeding the upper limit of normal (ULN) by 2 times, or total bilirubin levels exceeding the upper limit of normal (ULN) by 2 times during the screening period.
* Skin itching is not caused by chronic kidney disease, including allergic skin diseases (atopic dermatitis, urticaria, eczema, drug rash, etc.), physical skin diseases (prickly heat, solar rash, etc.), infectious skin diseases (insect bite dermatitis, chickenpox, measles, pyoderma, tinea corporis, etc.), cholestatic liver disease, etc.
* Severe cardiovascular disease patients: those who have been screened for NYHA class III or IV, acute myocardial infarction, unstable angina, large pericardial effusion, severe arrhythmia, or abnormal electrocardiogram within the previous 6 months and are deemed unsuitable for inclusion by the researchers.
* Screening for individuals who have been in the active stage of malignant tumors within the previous 12 months, or have received radiotherapy, chemotherapy, targeted therapy, and immunotherapy during this period.
* There are uncontrollable or drug-induced fungal, bacterial, viral, or other infections, including tuberculosis patients undergoing anti tuberculosis treatment, patients known to be infected with human immunodeficiency virus (HIV), etc.
* Hypertensive patients who cannot achieve good control with drug therapy: systolic blood pressure ≥ 180mmHg, or diastolic blood pressure ≥ 110mmHg.
* Patients who are currently using glucocorticoids and immunosuppressants.
* Patients with mental illness or cognitive impairment who are unable to correctly understand VAS scores and describe their own feelings.
* Received or adjusted antihistamines, systemic or local corticosteroids (excluding ear or eye preparations), calcineurin inhibitors, gabapentin, pregabalin, and other restricted combination drugs within 7 days prior to screening, or expected to change their treatment regimen during the study period.
* Started receiving or adjusting drugs that may affect the assessment of itch relief efficacy within 2 weeks prior to screening, including but not limited to antipsychotics, sedatives, selective serotonin reuptake inhibitors (SSRIs), anxiolytics, or tricyclic antidepressants, or expected to change their treatment regimen during the study period.
* Individuals with a history of drug abuse, drug dependence, or alcohol abuse within the past 12 months prior to screening.
* Select patients who have received phototherapy for pruritus within the previous month.
* Individuals who have used opioid receptor agonists or antagonists within the past 2 weeks prior to screening.
* Individuals with a known history of allergy to opioid drugs, or those who are allergic to test drug excipients.
* Individuals who have participated in other clinical studies and used the investigational drug or medical device within the 28 days prior to screening, or whose investigational drug is within 5 half lives prior to screening.
* Pregnant women, breastfeeding women, patients with positive pregnancy tests, or those who do not agree to use contraception during the study period.
* Other patients deemed unsuitable by researchers to participate in this clinical study.