A Maximum-Use Trial of Ruxolitinib Cream in Children Aged 2–11 Years with Moderate to Severe Atopic Dermatitis

Background: Ruxolitinib cream has demonstrated anti-inflammatory and antipruritic activity and was well tolerated in a phase 3 study in patients aged 2–11 years with mild to moderate atopic dermatitis (AD). Objective: This study examined the safety, tolerability, pharmacokinetics, efficacy, and quality of life (QoL) with ruxolitinib cream under maximum-use conditions and with longer-term use. Methods: Eligible patients were aged 2–11 years with moderate to severe AD [Investigator’s Global Assessment (IGA) score 3–4], and ≥ 35% affected body surface area (BSA). Patients applied 1.5% ruxolitinib cream twice daily to all baseline-identified lesions during the 4-week maximum-use period, then to active lesions only up to week 52 (patients with ≤ 20% affected BSA from week 8). Safety was assessed by frequency and severity of adverse events. Pharmacokinetic parameters were assessed as secondary endpoints, and efficacy and QoL were exploratory endpoints. Results: Overall, 29 patients (median age 5 years) were enrolled. Treatment-emergent adverse events were reported in 9/29 patients (31.0%); there were no adverse events of special interest (i.e., no serious infections, malignancies, major adverse cardiovascular events, or thromboses) during the study period. Mean steady-state plasma concentration during the maximum-use period was below the known half-maximal inhibitory concentration of Janus kinase–mediated myelosuppression in adults. Reductions in affected BSA and IGA observed at week 4 were sustained with as-needed use through 52 weeks. Improvements in patient-reported outcomes and QoL measures were consistent with efficacy results. Conclusion: These results support the safety of ruxolitinib cream in children (2–11 years) with AD, including those with extensive disease, and are consistent with previous efficacy findings. ClinicalTrials.gov Identifier: NCT05034822, first registered 30 August 2021.