Oral Janus kinase/SYK inhibition (ASN002) suppresses inflammation and improves epidermal barrier markers in patients with atopic dermatitis

J Allergy Clin Immunol. 2019 Oct;144(4):1011-1024. doi: 10.1016/j.jaci.2019.07.013. Epub 2019 Jul 26.


Background: Moderate-to-severe atopic dermatitis (AD) has been associated with significant disease burden and systemic abnormalities and often requires systemic treatments. Currently, safe and effective oral systemic treatments for moderate-to-severe AD are not yet available. ASN002 is an oral inhibitor of the Janus kinase/spleen tyrosine kinase signaling pathways, targeting several cytokine axes (TH2/TH22/TH17/TH1) and epidermal differentiation.

Objective: We sought to evaluate the effect of ASN002 on the cellular and molecular biomarker profile of patients with moderate-to-severe AD and to correlate changes in biomarkers to improvements in clinical severity measures and pruritus.

Methods: Thirty-six patients with moderate-to-severe AD were randomized to groups with dose escalation of ASN002 (20, 40, and 80 mg) and a placebo group. Skin biopsy specimens were performed at baseline, day 15, and day 29. Gene expression studies were conducted by using microarray and quantitative RT-PCR, and cellular infiltrates and protein expression were studied by using immunohistochemistry.

Results: ASN002 reversed the lesional skin transcriptome toward a nonlesional phenotype. It also rapidly and significantly suppressed key inflammatory pathways implicated in AD pathogenesis, including TH2 (IL4 receptor [IL4R], IL13, CCL13/monocyte chemoattractant protein 4, CCL17/thymus and activation-regulated chemokine, CCL18/pulmonary and activation-regulated chemokine, CCL22/macrophage-derived chemokine, and CCL26/eotaxin-3), TH17/TH22 (lipocalins, PI3/elafin, CCL20, S100A7/S100A8/S100A9, and IL36G/IL36RN), and TH1 (IFNG, CXCL9/CXCL11, and MX1) axes and barrier-related measures (filaggrin [FLG] and CLDN23). Significant improvements in AD gene signatures were observed predominantly in the 40- and 80-mg groups. Smaller and largely nonsignificant molecular changes were seen in the 20-mg and placebo groups.

Conclusion: The Janus kinase/spleen tyrosine kinase inhibitor ASN002 significantly suppressed key AD inflammatory pathways, corresponding to clinical response. ASN002 might be an effective novel therapeutic agent for moderate-to-severe AD.

Keywords: ASN002; Atopic dermatitis; Janus kinase; Janus kinase inhibitors; T(H)17; T(H)2; T(H)22; barrier; spleen tyrosine kinase; spleen tyrosine kinase inhibitors; tyrosine kinase.

Publication types

  • Clinical Trial, Phase I
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetonitriles / therapeutic use*
  • Adult
  • Anti-Inflammatory Agents / therapeutic use*
  • Biomarkers / metabolism
  • Dermatitis, Atopic / drug therapy*
  • Dermatitis, Atopic / pathology
  • Double-Blind Method
  • Enzyme Inhibitors / therapeutic use
  • Epidermis / drug effects
  • Epidermis / pathology
  • Female
  • Filaggrin Proteins
  • Humans
  • Inflammation / drug therapy
  • Inflammation / pathology
  • Janus Kinases / antagonists & inhibitors*
  • Male
  • Middle Aged
  • Piperidines / therapeutic use*
  • Pyridazines / therapeutic use*
  • Syk Kinase / antagonists & inhibitors*


  • Acetonitriles
  • Anti-Inflammatory Agents
  • Biomarkers
  • Enzyme Inhibitors
  • FLG protein, human
  • Filaggrin Proteins
  • Piperidines
  • Pyridazines
  • gusacitinib
  • Janus Kinases
  • SYK protein, human
  • Syk Kinase