A Multicenter, Randomized, Double-Blind, Placebo-Controlled 12-Week Study To Evaluate The Safety And Efficacy Of Oral Difelikefalin In Advanced Chronic Kidney Disease Subjects With Moderate-To-Severe Pruritus And Not On Dialysis With An Up To 52-Week Long-Term Extension

  • End date
    Aug 30, 2023
Updated on 29 September 2022


Global: 400 male and female subjects (200 per treatment group) with advanced CKD who are not on dialysis will be enrolled in the study. The sample size may be increased to 550 subjects based on the results of a planned interim assessment conducted when approximately 50% of the planned 400 subjects have been randomized and have either completed the 12-week Treatment Period 1 or have discontinued the 12-week Treatment Period 1 early


This study is divided into two different phases: an efficacy assessment phase and a long-term extension phase, both of which aims to evaluate the efficacy of oral difelikefalin at a dose of 1 mg once daily compared to placebo in reducing the intensity of itch after 12 weeks of treatment and 52 weeks of treatment, respectively, in advanced chronic kidney disease (CKD) subjects with moderate-to-severe pruritus and not on dialysis
Each Phase consist of two different durations:
• Efficacy Assessment phase: a 12-week study period consisting of:
- a 28 day screening period
- a 12 week treatment period
- a 1-week follow-up period
Long Term Extension phase: a 52 week study period consisting of:
- a 2-week transition period
- a 50-week treatment period
- a 1-week follow up period
• $56 per in-person visit and for 1 phone visit
• Patient is paid monthly
• Treatment period 1: 6 visits total = $336
• Treatment period 2: 8 visits total = $448
• Treatment period 1 & 2 = $784 all together

Condition Kidney Disease
Clinical Study IdentifierTX307741
Last Modified on29 September 2022


Yes No Not Sure

Inclusion Criteria

Willing and able to provide written informed consent prior to participating in this study
Able to communicate clearly with the study investigator and staff and complete the required study procedures and questionnaires
Subjects aged 18 to 85 years, inclusive, at the time of consent
Advanced CKD (ie, eGFR ≤20 mL/min/1.73 m2 calculated using CKD-EPI creatinine equation [2021]) based on either a screening laboratory serum creatinine value (eGFR ≤20 [±3] mL/min/1.73 m2) from this study or at least 2 documented serum creatinine values collected at least 90 days apart within 1 year prior to screening:a. Not currently on dialysis; and b. Subjects who have an eGFR less than 10 mL/min deemed stable (eg, based on electrolytes and volume status) for study entry by the principal investigator
Subject self-reports experiencing daily or near-daily pruritus for at least 6 months prior to screening
Inadequate response to current or prior topical treatments (including emollients) for pruritus prior to screening
Female subject is not pregnant or nursing during any period of the study
If female of childbearing potential, must have a negative serum β-human chorionic gonadotropin (β-hCG) pregnancy test result at screening and a negative urine pregnancy test result on Day 1 prior to randomization and at the end of the study
For females, subject must be of nonchildbearing potential defined as: a. Postmenopausal: A postmenopausal state is defined as no menses for 12 months without an alternative medical cause. For women aged 55 years or younger, postmenopausal state should be confirmed by a high follicle-stimulating hormone (FSH) level (> 40 IU/L or > 40 mIU/mL). No FSH confirmation is required in women older than 55 years; or b. Surgically sterile (hysterectomy, bilateral oophorectomy, or bilateral salpingectomy). Or, of childbearing potential involved in sexual intercourse that could lead to pregnancy and:Has a negative serum pregnancy test at screening and agrees to use an adequately effective method of contraception: (eg, hormonal contraceptives from at least 30 days prior to Day 1 until 7 days after the last dose of study drug [oral, intravaginal, transdermal, injectable, or implant], barrier method with spermicide, intrauterine device [IUD], intrauterine hormone releasing system [IUS], bilateral tubal ligation, vasectomized partner provided his vasectomy was performed ≥ 4 months prior to screening, or abstinence) from the time of informed consent until 7 days after the last dose of study drug
Note: The reliability of sexual abstinence needs to be evaluated in relation to the duration of the clinical study and the preferred and usual lifestyle of the subject. Periodic abstinence (calendar, symptothermal, post ovulation methods) is not acceptable
For male subjects involved in any sexual intercourse that could lead to pregnancy, subject must agree to use one of the effective contraceptive methods listed in Inclusion Criterion #9, from Day 1 (first day of treatment) until at least 7 days after the last study product administration. If the female partner of a male subject uses any of the hormonal contraceptive methods listed above and is the only form of contraception used, this contraceptive method should be used by the female partner from at least 4 weeks before Day 1 until at least 7 days after the last dose of study drug. Male subjects must agree not to donate sperm during the study and for 7 days after receiving the study drug. No restrictions are required for a vasectomized male provided his vasectomy was performed ≥ 4 months prior to screening
Prior to randomization on Day 1 of Treatment Period 1: a. Has recorded at least 4 WI-NRS scores during the 7-day Run-in Period; and
b. Has a mean baseline WI-NRS score ≥ 5, defined as the average of all non-missing scores reported during the 7-day Run-in Period
To be eligible for inclusion into the Long-term Extension Phase of the study, each subject will have to fulfill the additional following criteria at the time of entry into the Long-term Extension Phase
Has completed Treatment Period 1
Continues to meet inclusion criteria 1 through 10

Exclusion Criteria

Scheduled to receive renal replacement therapy (dialysis or kidney transplant) during the study
Has a concomitant disease, significant medical condition or physical/laboratory/ECG/vital signs abnormality that, in the opinion of the investigator, puts the subject at undue risk or interferes with interpretation of study results, impedes completion of the study procedures, or compromises the validity of the study measurements
Subject has a known history of clinically significant drug or alcohol abuse in the last year prior to Day 1
Subject had a major surgery within 8 weeks prior to Day 1 or has a major surgery planned during the study
Subjects with hypernatremia or a history of hypernatremia
Subjects unable to sense or respond to thirst appropriately
New or change of treatment received for itch, including antihistamines and corticosteroids (oral, intravenous, or topical), within 14 days prior to screening
New or change of prescription for gabapentinoids, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, anticonvulsants/mood stabilizers, tricyclic antidepressants, opioids or benzodiazepines within 14 days prior to screening
Serum alanine aminotransferase or aspartate aminotransferase greater than 2.5 times the reference upper limit of normal (ULN) and/or total bilirubin greater than 1.5 times the ULN at screening
Received an investigational drug within 30 days prior to the start of screening or is planning to participate in another clinical study while enrolled in this study
Has pruritus attributed to a cause other than chronic kidney disease (eg, pruritus associated with dermatological, hepatobiliary, neuropathic, and/or hematologic disorders)
Has localized itch restricted to the palms of the hands
Receiving an opioid antagonist (eg, naloxone, naltrexone) or opioid-mixed agonist-antagonist (eg, buprenorphine, nalbuphine) within 14 days prior to the start of screening and/or anticipates receiving such medications during the study
Received ultraviolet B treatment within 30 days prior to screening and/or anticipates receiving such treatment during the study
Has a known or suspected allergy to difelikefalin or any component of the investigational product
Subject has a history of cancer or lymphoproliferative disease within 5 years prior to Day 1. Subjects with successfully treated nonmetastatic cutaneous squamous cell or basal cell carcinoma and/or localized carcinoma in situ of the cervix are not to be excluded
Subject has a current condition resulting in chronic dehydration (eg, ongoing vomiting, chronic diarrhea) or a condition that, in the opinion of the investigator, could predispose to dehydration
A subject will be excluded from the Long-term Extension Phase of the study if any of the additional following criteria are met at the time of entry into the Long-term Extension Phase
Experienced AEs during the course of Treatment Period 1 that may preclude continued exposure to the study drug
Was noncompliant with protocol procedures during the Efficacy Assessment Phase of this study which is indicative of an inability to follow protocol procedures
Has developed a concomitant disease or any medical condition that, in the opinion of the investigator, could pose undue risk to the subject, impedes completion of the study procedures, or would compromise the validity of the study measurements
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