Difelikefalin Treatment Improves Symptoms of Itch-Dominant AD

Mark Lebwohl, MD

New data on the kappa-opioid receptor agonist difelikefalin (DFK) found that treatment showed clinically meaningful improvements in itch intensity, sleep, and quality of life in patients with itch-dominant atopic dermatitis.

The new findings of the oral agonist were presented at the American Academy of Dermatology (AAD) 2022 Annual Meeting in Boston.

Despite pruritis being a symptoms of atopic dermatitis, data on its effect on lesion severity is limited. Additionally, patients with intense pruritits have limited body surface area (BSA) involvement, and data on AD-related pruritis is lacking.

Currently, DFK is in development for the management of chronic pruritic conditions, with the drug receiving approval by the US Food and Drug Administration for the treatment of moderate to severe pruritis associated with chronic kidney disease in adults experiencing hemodialysis.

With phase 2 of the KARE study, Mark Lebwohl, MD, Icahn School of Medicine at Mount Sinai, New York, evaluated the efficacy and safety of DFK in subjects with atopic dermatitis and moderate to severe pruritis.

KARE was a phase 2, randomized, placebo-controlled study conducted with a subgroup of individuals with <10%, otherwise referred to as itch-dominant atopic dermatitis.

Patients treated with DFK were divided into several treatment groups including 0.25 mg, 0.5 mg, and 1.0 mg. A total of 82 DFK-treated patients were included in the study alongside 79 patients in the placebo group.

All subject has high disease burden despite limited Eczema Area and Severity (EASI) data, with approximately 64$ of patients having itch-dominant atopic dermatitis.

Efficacy endpoints consisted of a ≥4-point improvement in weekly mean of the daily I-NRS at week 12 , a ≥3-point improvement in Sleep Quality NRS at week 12, ratings of “very much improved” or “much improved” on the Patient Global Impression of Change at week 12, and ≥4-point improvement in Dermatology Life Quality Index (DLQI) score at week 12.

At 12 weeks, Lebwohl and colleagues observed that a greater proportion of subjects receiving DFK had achieved Sleep Quality NRS, with ≥3-point improvement across all doses.

Additionally, a significantly greater proportion of subjects achieved ≥4-point improvement in daily I-NRS with DFK compared to placebo at week 12, with. ≥4-point improvement across all DFK doses (P=0.033).

Subject across DFK dose groups also achieved greater responses at week 12 on the DLQI (≥4-point improvement) than the placebo group (62% vs 50%).

Finally, a substantial number of subjects across all DFK treatment groups has achieved either “much approved” or “very much approved” responses on the Patient Global Impression of Change, with 46% compared to 35% of patients on placebo.

Given the clinically meaningful improvements in disease severity and the limited effective treatment options for patients with itch-dominant atopic dermatitis, investigators believed that DFK-related improvements in pruritus “may fulfill an unmet need for effective relief of other symptoms, including sleep and QoL.”