Skin Microbiome's Emerging Role in Eczema

Ingrid Hein

May 29, 2019

For some patients with atopic dermatitis, an investigational agent — the combination Janus kinase (JAK) and spleen tyrosine kinase (SYK) inhibitor, known as ASN002, under development by Asana BioSciences — might reduce Staphylococcus aureus bacteria in the skin microbiome.

S aureus is frequently isolated from the skin of patients with atopic dermatitis, but the bacteria "is not found on the skin of healthy people," said Avidan Neumann, PhD, from the Institute of Environmental Medicine at Helmholtz Center Munich.

But the role of S aureus in atopic dermatitis is not clear. "We don't know what is the chicken and what is the egg," he explained.

It is unlikely that S aureus is the cause of eczema, he added. Rather, it probably takes advantage of a weakness in the skin barrier to thrive.

Neumann and his colleagues looked at the effect of ASN002 on the level of S aureus colonization in the skin microbiome of patients with mild to severe atopic dermatitis.

"This is a very hot topic," said Eyerich Kilian, PhD, from the Technical University of Munich, who will discuss treatments for atopic dermatitis in the pipeline at the meeting.

Atopic dermatitis affects about 3% to 4% of the population in the Western world, "and about 20% have severe cases," he told Medscape Medical News.

About two-thirds of patients respond well to JAK inhibitors "but, at the moment, we have no way to know if a patient will respond," he pointed out.

"There are no prognostic biomarkers in the field yet," Kilian said.

Neumann will present follow-up data from a phase 1b study of ASN002 (Br J Dermatol. Published online March 28, 2019) at the upcoming European Academy of Allergy and Clinical Immunology 2019 Congress in Lisbon, Portugal.

In the phase 1b study, the 36 patients with moderate to severe atopic dermatitis were randomized to oral ASN002 at one of three doses — 20 mg, 40 mg, or 80 mg — or placebo for 28 days.

On day 29, they assessed change in Eczema Area and Severity Index (EASI) score from baseline. The primary outcome was a decline in EASI score of at least 50% (EASI 50).

Percent of Patients Who Achieved a Decline in EASI Score of at Least 50% at 4 Weeks
ASN002 Dose Primary End Point Met, % P Value
20 mg 20 NS
40 mg 100 .003
80 mg 83 .03

For their follow-up study, Neumann and his colleagues assessed the skin microbiome of participants in this phase 1b trial at baseline, day 29, and day 43.

It is possible that the skin microbiome, particularly levels of S aureus, could help diagnose and guide treatment for dermatitis, and could "help solve the problem of who would respond to the drug so we can offer a more tailored therapy," Kilian added.

However, he pointed out, "we would need to have companion diagnostics" so that the skin microbiome could be assessed noninvasively.

Funding for the study was provided by Asana Biosciences. Neumann and Kilian have disclosed no relevant financial relationships.

European Academy of Allergy and Clinical Immunology (EAACI) 2019 Congress: Abstract OAS 33. To be presented June 5, 2019.

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