A Phase 2 Study of Oral Difelikefalin in Subjects With Chronic Kidney Disease and Moderate-to-Severe Pruritus

Efficacy and safety of different systemic drugs in the treatment of uremic pruritus among hemodialysis patients: a network meta-analysis based on randomized clinical trials

Aim

This network meta-analysis was to analyze and rank the efficacy and safety of different systemic drugs in the treatment of uremic pruritus (UP) among hemodialysis patients.

Method

PubMed, Embase, Cochrane Library, and Web of Science databases were searched from inception to 10 July 2023 for randomized controlled trials (RCTs) investigating different drugs in the treatment of UP among hemodialysis patients. Drugs including cromolyn sodium, dexchlorpheniramine, difelikefalin, gabapentin, hydroxyzine, ketotifen, melatonin, montelukast, nalbuphine, nalfurafine, nemolizumab, nicotinamide, pregabalin, sertraline, thalidomide, and placebo were assessed. Outcome measures, including pruritus relief, response, and adverse events, were analyzed. Network plots, forest plots, league tables, and the surface under the cumulative ranking (SUCRA) probabilities were depicted for each outcome.

Results

The network meta-analysis retrieved 22 RCTs. Gabapentin (69.74%) had the highest likelihood to be the most effective drug for pruritus relief in UP patients receiving hemodialysis, followed by cromolyn sodium and hydroxyzine. Thalidomide (60.69%) and gabapentin (58.99%) were associated with significantly more drug responses for treating UP among patients receiving hemodialysis. Patients who were treated with gabapentin (40.01%) were likely to have risks of adverse events and dizziness. Lower risks of adverse events, nausea, and diarrhea were found in patients who received cromolyn sodium and lower risks of somnolence.

Conclusion

This study suggests considering gabapentin treatment when facing a patient suffering from UP. This study provides a reference for the selection of drug therapy for UP patients receiving hemodialysis.

Intravenous difelikefalin for the treatment of hemodialysis pruritus

INTRODUCTION

Patients with chronic kidney disease (CKD) undergoing hemodialysis often experience significant itch secondary to their condition and a subsequent reduction in their overall quality of life. Current treatments are underwhelming, necessitating the search for new, effective therapeutic options to combat itch in this population.

AREAS COVERED

The purpose of this review is to explore the available data for the use of intravenous difelikefalin in patients with CKD undergoing hemodialysis. The pathophysiology of CKD-associated itch is multifactorial, with one proposed mechanism involving an imbalance in the endogenous opioid system, favoring upregulation of itch-activating μ-opioid receptors (MORs) and downregulation of itch-inhibiting κ-opioid receptors (KORs). Dysregulation of the immune system is also involved. Difelikefalin is a recent FDA approved treatment that functions as peripherally acting KOR agonist, targeting this imbalance in the endogenous opioid system seen in CKD patients with itch and having an anti-inflammatory effect on immune cells. Clinical data on intravenous difelikefalin is promising regarding its ability to reduce itch in CKD patients on hemodialysis and improve patient quality of life, with few, mild adverse side effects.

EXPERT OPINION

As intravenous difelikefalin becomes more widely used in the clinical setting, further studies assessing long-term efficacy and safety will be needed.

CKD-Associated Pruritus and Clinical Outcomes in Nondialysis CKD

Rationale & Objective

Itching is a frequent symptom experienced by people with chronic kidney disease (CKD). We investigated the associations of CKD-associated pruritus (CKD-aP) with clinical outcomes.

Study Design

This was a longitudinal cohort study.

Setting & Participants

Patients from Brazil, France, and the United States enrolled in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) from 2013 to 2021, an international prospective cohort study of adults with nondialysis dependent CKD, and an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2 were included.

Exposure

CKD-aP was self-reported by response to the question: "During the past 4 weeks, to what extent were you bothered by itchy skin?"

Outcomes

The outcomes were as follows: CKD progression, kidney replacement therapy (KRT) initiation, mortality, hospitalization, cardiovascular events, infection events.

Analytical Approach

Associations with time-to-event outcomes were investigated using Cox proportional hazards models adjusted for potential confounders.

Results

There were 4,410 patients from 91 clinics with a median age of 69 years and a median eGFR at patient questionnaire completion of 29 (21-38) mL/min/1.73 m2. The proportion of patients not at all, somewhat, moderately, very much, and extremely bothered by itchy skin was 49%, 27%, 13%, 7%, and 3%, respectively. Patients with more advanced stages of CKD, older age, and greater comorbidities reported to be more likely bothered by itchy skin. Among patients at least moderately bothered, 23% were prescribed at least 1 pharmacotherapy (35% in the United States, 19% in France, 4% in Brazil), including antihistamine (10%), gabapentin (6%), topical corticosteroids (4%), pregabalin (3%), or sedating antihistamine (3%). The HR (95% CI) for patients extremely (vs not at all) bothered was 1.74 (1.11-2.73) for all-cause mortality, 1.56 (1.11-2.18) for all-cause hospitalization, and 1.84 (1.22-2.75) for cardiovascular events. As CKD-aP severity increased, patients also had higher rates of infection events (P = 0.04); CKD-aP severity was not associated with KRT initiation (P = 0.20) or CKD progression (P = 0.87).

Limitations

The limitations were 25% nonresponse rate, recall bias, and residual confounding factors.

Conclusions

These results demonstrate a strong association between severe itch and clinical outcomes, providing the nephrology community new insights into the possible adverse consequences of CKD-aP in individuals with nondialysis CKD, and warrant further exploration.

Plain-Language Summary

Chronic kidney disease-associated pruritus (CKD-aP) is a common disturbing symptom of chronic kidney disease (CKD). This article analyzes longitudinal data from the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) to describe prevalence of CKD-aP in 4,410 individuals with nondialysis CKD, and its association with clinical outcomes. We found that 51% of the surveyed population were bothered by pruritus. CKD-aP was more prevalent in those with more advanced stages of CKD, older age, and with more comorbid conditions. Compared to those not at all bothered by pruritus, those who were extremely bothered had a higher risk of all-cause mortality, hospitalizations, and cardiovascular events. Severity of CKD-aP was not associated with CKD progression or initiation of kidney replacement therapy.

Chronic Kidney Disease-Associated Pruritus, Still a Vexing Problem

Chronic kidney disease-associated pruritus (CKD-aP), formerly termed uremic pruritus, is a severely distressing condition that is common (60% of patients on dialysis) and frequently underdiagnosed and untreated.1,2 The pruritus can be severe enough to diminish sleep and is associated with worse mortality rates, as demonstrated in several large studies.1,2 It can also occur in nondialysis patients with stage 3 to 5 CKD, with an increasing prevalence in patients with worsening kidney function, age, and medical comorbidities. The pathophysiology likely involves many factors and molecules.3.