Characterization of Selective and Potent JAK1 Inhibitors Intended for the Inhaled Treatment of Asthma

Drug Des Devel Ther. 2022 Aug 31:16:2901-2917. doi: 10.2147/DDDT.S354291. eCollection 2022.

Abstract

Purpose: Janus kinase 1 (JAK1) is implicated in multiple inflammatory pathways that are critical for the pathogenesis of asthma, including the interleukin (IL)-4, IL-5, IL-13, and thymic stromal lymphopoietin cytokine signaling pathways, which have previously been targeted to treat allergic asthma. Here, we describe the development of AZD0449 and AZD4604, two novel and highly selective JAK1 inhibitors with promising properties for inhalation.

Methods: The effects of AZD0449 and AZD4604 in JAK1 signaling pathways were assessed by measuring phosphorylation of signal transducer and activator of transcription (STAT) proteins and chemokine release using immunoassays of whole blood from healthy human volunteers and rats. Pharmacokinetic studies performed on rats evaluated AZD0449 at a lung deposited dose of 52 μg/kg and AZD4604 at 30 µg/kg. The efficacy of AZD0449 and AZD4604 was assessed by evaluating lung inflammation (cell count and cytokine levels) and the late asthmatic response (average enhanced pause [Penh]).

Results: Both compounds inhibited JAK1-dependent cytokine signaling pathways in a dose-dependent manner in human and rat leukocytes. After intratracheal administration in rats, both compounds exhibited low systemic exposures and medium-to-long terminal lung half-lives (AZD0449, 34 hours; AZD4604, 5 hours). Both compounds inhibited STAT3 and STAT5 phosphorylation in lung tissue from ovalbumin (OVA)-challenged rats. AZD0449 and AZD4604 also inhibited eosinophilia in the lung and reduced the late asthmatic response, measured as Penh in the OVA rat model.

Conclusion: AZD0449 and AZD4604 show potential as inhibitors of signaling pathways involved in asthmatic immune responses, with target engagement demonstrated locally in the lung. These findings support the clinical development of AZD0449 and AZD4604 for the treatment of patients with asthma.

Keywords: AZD0449; AZD4604; JAK; STAT.

MeSH terms

  • Animals
  • Asthma* / metabolism
  • Cytokines / metabolism
  • Humans
  • Janus Kinase 1 / metabolism
  • Janus Kinase Inhibitors* / pharmacology
  • Lung / metabolism
  • Ovalbumin
  • Rats
  • Signal Transduction

Substances

  • Cytokines
  • Janus Kinase Inhibitors
  • Ovalbumin
  • JAK1 protein, human
  • Janus Kinase 1

Grants and funding

AstraZeneca funded this study and participated in study design, data collection, data analysis, data interpretation, and writing the study report. The Swedish Research Council funded Lars Rönnblom. AstraZeneca develops and markets treatments for asthma. AstraZeneca reviewed the publication, without influencing the opinions of the authors, to ensure medical and scientific accuracy and the protection of intellectual property. The corresponding author had access to all data in the study and had final responsibility for the decision to submit the manuscript for publication.