Safety and Effectiveness of Difelikefalin in Patients With Moderate-to-Severe Pruritus Undergoing Hemodialysis: An Open-Label, Multicenter Study

Abstract

Rationale & ObjectiveIndividuals with chronic kidney disease frequently suffer from chronic kidney disease-associated pruritus (CKD-aP), impacting sleep quality and quality of life (QoL) and increasing the likelihood of depression. Difelikefalin is a kappa-opioid receptor agonist recently approved in the United States for the treatment of moderate-to-severe CKD-aP in hemodialysis patients. Study 3105 was conducted to further assess the safety of difelikefalin and the effects on pruritus and QoL.Study DesignOpen-label, multicenter, single-arm intervention trial.Setting & ParticipantsMaintenance hemodialysis patients with moderate-to-severe CKD-aP at enrollment.InterventionIntravenous difelikefalin 0.5 μg/kg after each hemodialysis session for 12 weeks.OutcomesThe primary outcome was safety of difelikefalin. Secondary outcomes included: effectiveness of reducing itch intensity, assessed by the Worst Itching Intensity Numerical Rating Scale (WI-NRS); improving itch-related QoL, assessed with 5-D itch and Skindex-10 scales; and improvement of sleep, assessed with the Sleep Quality Numerial Rating Scale. Clinically meaningful thresholds for improvement in itch and QoL were previously established in this population.ResultsAmong 222 participants with baseline WI-NRS ≥5, mean [standard deviation] WI-NRS was 7.6 [1.3], mean age 58 years, 55% were male, and mean dialysis duration was 5.9 years; 197 participants (89%) completed treatment. Treatment-related treatment-emergent adverse events were reported in 16 participants (7.2%); those most commonly reported were somnolence (1.8%), hypoesthesia (1.4%), nausea (0.9%), and dizziness (0.9%). No deaths or serious treatment-emergent adverse events were considered treatment-related. Clinically meaningful reduction in itch intensity (≥3-point improvement) was reported by 74% of participants, with 70% and 63% also reporting a clinically relevant improvement in QoL as measured by 5-D itch and Skindex-10. Sleep quality improvement (≥3-point reduction on the Numerical Rating Scale) was reported in 66% of participants.LimitationsNo placebo control group.ConclusionsDifelikefalin was well tolerated, and treatment was associated with clinically meaningful improvements in itch intensity and itch-related QoL measures as well as improvements in sleep quality among individuals receiving hemodialysis who had moderate-to-severe CKD-aP, providing important insights into expected real-world effectiveness.FundingCara Therapeutics.Trial RegistrationNCT03998163.