Safety, Pharmacokinetics, and Efficacy of Ruxolitinib Cream in Children and Adolescents With Atopic Dermatitis

To evaluate safety, tolerability, pharmacokinetics, and efficacy of ruxolitinib cream (topical formulation of JAK1/JAK2 inhibitor ruxolitinib) in children and adolescents with atopic dermatitis (AD).

The study population included patients aged 2 to 17 years with AD affecting 8% to 20% of their body surface area (excluding scalp) and had an Investigator’s Global Assessment score of 2 or greater.

The study population was enrolled stepwise into 6 cohorts defined by age (12–17 years, 7 to <12 years, and 2 to <7 years) and ruxolitinib cream strength (0.5%, 0.75%, or 1.5%) with 2 cohorts within in each range. Ruxolitinib cream was applied topically twice daily as a thin film to the affected areas for 28 days. Assessments for safety, pharmacokinetics, and efficacy were collected on day 1 (baseline), day 10 (week 2), and day 29 (week 4).

A total of 71 patients were enrolled into the 6 cohorts. Treatment emergent adverse events related to ruxolitinib cream occurred in 4 patients (5.6%). No clinically significant changes in bone biomarkers, hematology, or chemistry values were observed. Plasma concentrations of ruxolitinib within all cohorts (range 23.1–97.9 nM) were generally low. All patients had reductions in baseline Eczema Area and Severity Index scores at week 2, and the mean percentage improvement increased in 5 out of 6 cohorts at week 4. Investigator’s Global Assessment treatment success was achieved by 5 out of 6 cohorts at week 2 and was increased in all cohorts at week 4. Mean total body surface area affected by AD and Patient-Oriented Eczema Measure decreased in all cohorts at week 2, with further decreases in all cohorts at week 4. Substantial improvements were seen in itch scores in cohorts 1 to 4 (assessed only in cohorts with children aged 7 and older) at week 2 and were maintained or improved at week 4.

In an open label study, ruxolitinib cream was a safe and well tolerated treatment option for children aged 2 to 17 with atopic dermatitis affecting <20% of body surface area.

Ruxolitinib cream is currently approved by the United States Food and Drug Administration for treatment of mild to moderate AD in patients 12 years and older. This phase 1 study highlights the safety and efficacy of ruxolitinib cream as a potential treatment option for pediatric patients in which the prevalence of AD is higher. Despite reassuring initial studies, the use of ruxolitinib cream is currently restricted to patients with <20% body surface area affected, limiting its utility in patients with severe or widespread AD. Additional, further studies in this younger age group and on the long-term safety of topical JAK inhibitors need to be performed.