Study Finds Topical Ruxolitinib Effective, Safe for Children With AD

BERLIN – Based on a phase 3 trial, treatment with the topical Janus kinase (JAK) inhibitor ruxolitinib appears to be as safe and effective for the control of atopic dermatitis (AD) in children aged 2-11 years as previously shown in adolescents and adults for whom it already has an approved indication.

In this study – TRUE-AD3 – systemic exposure to ruxolitinib, which is selective for JAK1 and 2, was followed closely, and the low mean plasma concentrations "suggest systemic JAK inhibition is highly unlikely," Lawrence F. Eichenfield, MD, professor of dermatology and pediatrics at the University of California, San Diego, said at the annual congress of the European Academy of Dermatology and Venereology.

For example, at a plasma concentration no greater than 27 nM in both younger and older patients at 4 weeks and again at 8 weeks, the systemic exposure was about a tenth of that (281 nM) previously associated with myelosuppression, he reported.

Given the boxed warning for oral JAK inhibitors, which was based largely on a 2022 study in adults with rheumatoid arthritis that associated tofacitinib, a nonspecific JAK inhibitor, with an increased risk of thrombotic events in adults already at risk for these events, safety was a focus of this phase 3 trial. The boxed warning is also in the labeling for topical ruxolitinib, 1.5% (Opzelura), approved for treating to mild to moderate atopic dermatitis in patients 12 years of age and older.

Dr. Eichenfield said there were no significant safety signals in the younger pediatric population. "There were no treatment-emergent adverse events suggestive of systemic JAK inhibition," he said. This not only included the absence of serious infections, cardiac events, thromboses, or malignancies, but there was no signal of hematologic abnormalities, such as change in hemoglobin or neutrophil count.

Application site reactions

Rather, in the study of children ages 2-11, the only adverse events associated with topical ruxolitinib not observed in the control arm, which received the vehicle alone, were application site reactions, such as pain, erythema, and irritation. None of these occurred in more than 3% of those randomized to ruxolitinib regardless of dose.

Overall, in the trial, which randomized 329 patients ages from 2 to under 12 years with mild to moderate AD to ruxolitinib 1.5% cream, ruxolitinib 0.75% cream, or vehicle in a 2:2:1 fashion, there were just two (0.8%) discontinuations in the ruxolitinib groups (one in each dosing arm). There were none in the vehicle arm.

The safety supports an expansion of the AD indication for topical ruxolitinib in young children, because the rates of response were very similar to that seen in adolescents and adults in the previously published TRUE AD-1 and TRUE AD-2 trials, he said.

For the primary endpoint of Investigator's Global Assessment (IGA) score of 0 (clear) or 1 (almost clear) with at least a 2 grade improvement in IGA score from baseline, the response rates were 56.5%, 36.6%, and 10.8% for ruxolitinib 1.5%, ruxolitinib 0.75%, and vehicle respectively, at 8 weeks (P < .0001 for both doses relative to vehicle).

For the secondary efficacy endpoint of 75% or greater clearance on the Eczema Area and Severity Index, the rates were 67.2%, 51.5%, and 15.4%, for ruxolitinib 1.5%, ruxolitinib 0.75%, and vehicle respectively. Again, the advantage of both doses of ruxolitinib relative to vehicle was highly statistically significant (P < .0001).

Control of itch, evaluated with the Numerical Rating Scale was only evaluated in children 6-2 because of concern of the reliability of reporting in younger children. Control was defined as at least a 4-point improvement from baseline. It was achieved by 43.4%, 37.5%, and 29.7% by week 8 in the arms receiving the higher dose of ruxolitinib, the lower dose, and vehicle, respectively. The median time to achieving itch control was 11 days, 13 days, and 23 days, respectively. For all of these endpoints, the separation of the curves was readily apparent within the first 2 weeks.

The efficacy and tolerability of ruxolitinib appeared to be similar in younger children (ages 2-6) relative to older children.

Extension study in children near completion

Most of the patients who participated in TRUE AD-3 have been rolled over to the open-label extension trial, which is nearing completion. Those originally randomized to vehicle have been rerandomized to the lower or higher dose of ruxolitinib.

While this trial was focused on ruxolitinib as monotherapy, Thrasyvoulos Tzellos, MD, head of the department of dermatology, Nordland Hospital Trust, Bødo, Norway, questioned whether this is will be how it will be used in clinical practice. With the increasing array of therapies for AD, the "concept of combination therapy becomes more and more relevant," he said after Dr. Eichenfield's presentation.

Questioning whether an effective nonsteroidal anti-inflammatory agent like ruxolitinib should be considered a first-line treatment in mild disease or an adjunctive treatment for AD of any severity, he suggested that it might be best considered within a combination.

Dr. Eichenfield agreed. "Once we get the drug approved in a controlled trial, I think we then figure out how to use it in clinical practice." Based on his own use of ruxolitinib in adults, he noted that he has not seen this drug replace other therapies so much as provide another option for control.

"We have an increasing armamentarium of drugs to use for involvement in different areas of the body in order to get more long-term control of disease," he said. As an effective topical nonsteroidal drug, he believes its addition to clinical care in younger children, if approved, will be meaningful.

Dr. Eichenfield disclosed financial relationships with more multiple pharmaceutical companies, including Incyte, the manufacturer of ruxolitinib cream that provided funding for the True-AD trials. Dr. Tzellos reported financial relationships with AbbVie and UCB.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

Credits:

Lead image: Incyte

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Cite this: Study Finds Topical Ruxolitinib Effective, Safe for Children With AD - Medscape - Nov 01, 2023.