Inhaled Janus Kinase (JAK) inhibitors for the treatment of asthma

Discovery of the Potent and Selective Inhaled Janus Kinase 1 Inhibitor AZD4604 and Its Preclinical Characterization

JAK-STAT cytokines are critical in regulating immunity. Persistent activation of JAK-STAT signaling pathways by cytokines drives chronic inflammatory diseases such as asthma. Herein, we report on the discovery of a highly JAK1-selective, ATP-competitive series of inhibitors having a 1000-fold selectivity over other JAK family members and the approach used to identify compounds suitable for inhaled administration. Ultimately, compound 16 was selected as the clinical candidate, and upon dry powder inhalation, we could demonstrate a high local concentration in the lung as well as low plasma concentrations, suggesting no systemic JAK1 target engagement. Compound 16 has progressed into clinical trials. Using 16, we found JAK1 inhibition to be more efficacious than JAK3 inhibition in IL-4-driven Th2 asthma.

Current and future developments in the pharmacology of asthma and COPD: ERS seminar, Naples 2022

Pharmacological management of airway obstructive diseases is a fast-evolving field. Several advances in unravelling disease mechanisms as well as intracellular and molecular pathways of drug action have been accomplished. While the clinical translation and implementation of in vitro results to the bedside remains challenging, advances in comprehending the mechanisms of respiratory medication are expected to assist clinicians and scientists in identifying meaningful read-outs and designing clinical studies. This European Respiratory Society Research Seminar, held in Naples, Italy, 5-6 May 2022, focused on current and future developments of the drugs used to treat asthma and COPD; on mechanisms of drug action, steroid resistance, comorbidities and drug interactions; on prognostic and therapeutic biomarkers; on developing novel drug targets based on tissue remodelling and regeneration; and on pharmacogenomics and emerging biosimilars. Related European Medicines Agency regulations are also discussed, as well as the seminar's position on the above aspects.

Long-term follow-up of Janus-kinase inhibitor and novel active disease biomarker in juvenile dermatomyositis

OBJECTIVE

To evaluate the use of Janus kinase inhibitor (JAKi) in treating JDM and develop cytokine biomarkers of active disease.

METHODS

This study involved a retrospective cohort study that evaluated JAKi in 101 JDM patients as well as a cross-sectional study of cytokines in 128 JDM patients and 30 controls between November 2017 and December 2021 in the Affiliated Children's Hospital of Capital Institute of Pediatrics (China).

RESULTS

During the median follow-up period of 19 months, 65.5% of the patients had improved rashes, and CAT-BM scores decreased. Overall, 39.6% of JDM patients eliminated glucocorticoids. Muscle strength was improved in all patients who had abnormal muscle strength before JAKi use. Patients and parents provided positive subjective reviews of JAKi, and no serious adverse events were reported. Potential side effects of JAKi included abnormal leukopoenia (14/95) and cough (16/83), which affected over 10% of the JDM patients. In the cytokine analysis, 12/34 cytokines were significantly elevated in active JDM patients. Compared with active JDM patients with multiple phenotypes, active JDM patients with only rashes demonstrated lower cytokine levels. Anti-NXP2-positive active patients had lower cytokine levels compared with those without positive anti-NXP2 antibodies. Among all increased cytokines, IL-1RA changed most dramatically, reaching over 793 times the mean of normal values. We developed a panel composed of six cytokines to differentiate active or stable status in our cohort (area under the curve = 0.8486, P < 0.05).

CONCLUSION

The preliminary evidence suggested that JAKi is a relatively safe and effective alternative for JDM patients. Cytokine profiles could well reflect the inflammatory status of JDM patients.

Recent insights into comorbidities in atopic dermatitis

INTRODUCTION

The relationship between atopic dermatitis and atopic diseases such as food allergies, asthma, and allergic rhinitis in terms of co-occurrence, underlying mechanisms, and therapy is well documented. There is increasing evidence that atopic dermatitis is associated with non-atopic comorbidities such as cardiac, autoimmune, and neuropsychological comorbidities, as well as cutaneous and extracutaneous infections, establishing atopic dermatitis as a systemic disease.

AREAS COVERED

The authors reviewed evidence on atopic and non-atopic comorbidities of atopic dermatitis. A literature search was conducted in PubMed for peer-reviewed articles published until October 2022.

EXPERT OPINION

Atopic and non-atopic diseases coexist with atopic dermatitis more often than would be expected by chance. The effect of biologics and small molecules on atopic and non-atopic comorbidities may contribute to a better understanding of the relationship between atopic dermatitis and its comorbidities. Their relationship needs to be explored further to dismantle the underlying mechanism and move toward an atopic dermatitis endotype-based therapeutic approach.

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

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.

Impact of P-gp and BCRP on pulmonary drug disposition assessed by PET imaging in rats

P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) are two efflux transporters which are expressed in the apical (i.e. airway lumen-facing) membranes of lung epithelial cells. To assess the influence of P-gp and BCRP on the pulmonary disposition of inhaled drugs, we performed positron emission tomography (PET) imaging in rats after intratracheal aerosolization of two model P-gp/BCRP substrate radiotracers (i.e. [¹¹C]erlotinib and [¹¹C]tariquidar). We studied rat groups in which both transporters were active (i.e. wild-type rats), either of the two transporters was inactive (Abcb1a/b^(-/-) and Abcg2^(-/-) rats) or both transporters were inactive (Abcg2^(-/-) rats in which pulmonary P-gp activity was inhibited by treatment with unlabeled tariquidar). PET-measured lung distribution data were compared with brain-to-plasma radioactivity concentration ratios measured in a gamma counter at the end of the PET scan. For [¹¹C]erlotinib, lung exposure (AUC_lungs) was moderately but not significantly increased in Abcb1a/b^(-/-) rats (1.6-fold) and Abcg2^(-/-) rats (1.5-fold), and markedly (3.6-fold, p < 0.0001) increased in tariquidar-treated Abcg2^(-/-) rats, compared to wild-type rats. Similarly, the brain uptake of [¹¹C]erlotinib was substantially (4.5-fold, p < 0.0001) increased when both P-gp and BCRP activities were impaired. For [¹¹C]tariquidar, differences in AUC_lungs between groups pointed into a similar direction as for [¹¹C]erlotinib, but were less pronounced and lacked statistical significance. Our study demonstrates functional P-gp and BCRP activity in vivo in the lungs and further suggests functional redundancy between P-gp and BCRP in limiting the pulmonary uptake of a model P-gp/BCRP substrate, analogous to the blood-brain barrier. Our results suggest that pulmonary efflux transporters are important for the efficacy and safety of inhaled drugs and that their modulation may be exploited in order to improve the pharmacokinetic and pharmacodynamic performance of pulmonary delivered drugs.

Molecular and Immunomodulatory Actions of New Antiasthmatic Agents: Exploring the Diversity of Biologics in Th2 Endotype Asthma

Asthma is a major respiratory disorder characterised by chronic inflammation and airway remodelling. It affects about 1-8% of the global population and is responsible for over 461,000 deaths annually. Until recently, the pharmacotherapy of severe asthma involved high doses of inhaled corticosteroids in combination with β-agonist for prolonged action, including theophylline, leukotriene antagonist or anticholinergic yielding limited benefit. Although the use of newer agents to target Th2 asthma endotypes has improved therapeutic outcomes in severe asthmatic conditions, there seems to be a paucity of understanding the diverse mechanisms through which these classes of drugs act. This article delineates the molecular and immunomodulatory mechanisms of action of new antiasthmatic agents currently being trialled in preclinical and clinical studies to remit asthmatic conditions. The ultimate goal in developing antiasthmatic agents is based on two types of approaches: either anti-inflammatory or bronchodilators. Biologic and most small molecules have been shown to modulate specific asthma endotypes, targeting thymic stromal lymphopoietin, tryptase, spleen tyrosine kinase (Syk), Janus kinase, PD-L1/PD-L2, GATA-3, and CD38 for the treatment and management of Th2 endotype asthma.

Effects of inhaled JAK inhibitor GDC-4379 on exhaled nitric oxide and peripheral biomarkers of inflammation

BACKGROUND

Janus Kinases (JAKs) mediate activity of many asthma-relevant cytokines. GDC-0214, an inhaled small molecule JAK1 inhibitor, has previously been shown to reduce fractional exhaled nitric oxide (FeNO) in patients with mild asthma, but required an excessive number of inhalations.

AIM

To assess whether GDC-4379, a new inhaled JAK inhibitor, reduces FeNO and peripheral biomarkers of inflammation.

METHODS

This study assessed the activity of GDC-4379 in a double-blind, randomized, placebo-controlled, Phase 1 study in patients with mild asthma. Participants included adults (18-65y) with a diagnosis of asthma for ≥6 months, forced expiratory volume in 1 s (FEV₁)> 70% predicted, FeNO >40 ppb, using as-needed short-acting beta-agonist medication only. Four sequential, 14-day, ascending-dose cohorts (10 mg QD, 30 mg QD, 40 mg BID, and 80 mg QD) of 12 participants each were randomized 2:1 to GDC-4379 or placebo. The primary activity outcome was percent change from baseline (CFB) in FeNO to Day 14 compared to the pooled placebo group. Safety, tolerability, pharmacokinetics, and pharmacodynamic biomarkers, including blood eosinophils, serum CCL17, and serum CCL18, were also assessed.

RESULTS

Of 48 enrolled participants, the mean age was 25 years and 54% were female. Median (range) FeNO at baseline was 79 (41-222) ppb. GDC-4379 treatment led to dose-dependent reductions in FeNO. Compared to placebo, mean (95% CI) percent CFB in FeNO to Day 14 was: -6 (-43, 32) at 10 mg QD, -26 (-53, 2) at 30 mg QD, -55 (-78, -32) at 40 mg BID and -52 (-72, -32) at 80 mg QD. Dose-dependent reductions in blood eosinophils and serum CCL17 were also observed. Higher plasma drug concentrations corresponded with greater FeNO reductions. No serious AEs occurred. The majority of AEs were mild to moderate. The most common AEs were headache and oropharyngeal pain. Minor changes in neutrophils were noted at 80 mg QD, but were not considered clinically meaningful.

CONCLUSIONS

In patients with mild asthma, 14-day treatment with GDC-4379 reduced FeNO levels and peripheral biomarkers of inflammation. Treatment was well tolerated without any major safety concerns.

AUSTRALIAN NEW ZEALAND CLINICAL TRIALS REGISTRY

ACTRN12619000227190.

Strategies Targeting Type 2 Inflammation: From Monoclonal Antibodies to JAK-Inhibitors

Bronchial asthma and its frequent comorbidity chronic rhinosinusitis (CRS), are characterized by an inflammatory process at lower and upper respiratory tract, with a variability in terms of clinical presentations (phenotypes) and distinct underpin pathophysiological mechanisms (endotypes). Based on the characteristics of inflammation, bronchial asthma can be distinguished into type 2 (eosinophilic) or nontype 2 (noneosinophilic) endotypes. In type 2 asthma endotype, the pathogenic mechanism is sustained by an inflammatory process driven by Th2 cells, type 2 innate lymphoid cells (ILC2) and type 2 cytokines, which include interleukin (IL)-4, IL-5, IL-9 and IL-13. The definition of asthma and chronic rhinusinusitis phenotype/endotype is crucial, taking into account the availability of novel biologic agents, such as monoclonal antibodies targeting the classical type 2 cytokines. Recently, new therapeutic strategies have been proposed and analyzed in preliminary clinical trials. Among them Janus kinase (JAK) inhibitors, now largely used for the treatment of other chronic inflammatory diseases such as rheumatoid arthritis and inflammatory bowel diseases, is receiving great relevance. The rationale of this strategy derives from the data that JAK is a tyrosine kinase involved in the signaling of T cell receptor and of several cytokines that play a role in allergic respiratory disease, such as IL-2, IL-4 and IL-9. In this review, we discuss whether treatment with biological agents and JAK inhibitors may be equally effective in controlling type 2 inflammatory process in both asthma and CRS.

JAK inhibitors for asthma

Asthma is an inflammatory disease of the airways characterized by intermittent episodes of wheezing, chest tightness, and cough. Many of the inflammatory pathways implicated in asthma involve cytokines and growth factors that activate Janus kinases (JAKs). The discovery of the JAK/signal transducer and activator of transcription (STAT) signaling pathway was a major breakthrough that revolutionized our understanding of cell growth and differentiation. JAK inhibitors are under active investigation for immune and inflammatory diseases, and they have demonstrated clinical efficacy in diseases such as rheumatoid arthritis and atopic dermatitis. Substantial preclinical data support the idea that inhibiting JAKs will ameliorate airway inflammation and hyperreactivity in asthma. Here, we review the rationale for use of JAK inhibitors in different asthma endotypes as well as the preclinical and early clinical evidence supporting such use. We review preclinical data from the use of systemic and inhaled JAK inhibitors in animal models of asthma and safety data based on the use of JAK inhibitors in other diseases. We conclude that JAK inhibitors have the potential to usher in a new era of anti-inflammatory treatment for asthma.

Inhaled JAK inhibitor GDC-0214 reduces exhaled nitric oxide in patients with mild asthma: A randomized, controlled, proof-of-activity trial

BACKGROUND

The Janus kinase (JAK) pathway mediates the activity of many asthma-relevant cytokines, including IL-4 and IL-13. GDC-0214 is a potent, inhaled, small-molecule JAK inhibitor being developed for the treatment of asthma.

OBJECTIVE

We sought to determine whether GDC-0214 reduces fractional exhaled nitric oxide (Feno), a JAK1-dependent biomarker of airway inflammation, in patients with mild asthma.

METHODS

We conducted a double-blind, randomized, placebo-controlled, phase 1 proof-of-activity study in adults with mild asthma and Feno higher than 40 parts per billion (ppb). Subjects were randomized 2:1 (GDC-0214:placebo) into 4 sequential ascending-dose cohorts (1 mg once daily [QD], 4 mg QD, 15 mg QD, or 15 mg twice daily). All subjects received 4 days of blinded placebo, then 10 days of either active drug or placebo. The primary outcome was placebo-corrected percent reduction in Feno from baseline to day 14. Baseline was defined as the average Feno during the blinded placebo period. Pharmacokinetics, safety, and tolerability were also assessed.

RESULTS

Thirty-six subjects (mean age, 28 years; 54% females) were enrolled. Mean Feno at baseline across all subjects was 93 ± 43 ppb. At day 14, placebo-corrected difference in Feno was -23% (95% CI, -37.3 to -9) for 15 mg QD and -42% (95% CI, -57 to -27.4) for 15 mg twice daily. Higher plasma exposure was associated with greater Feno reduction. No dose-limiting adverse events, serious adverse events, or treatment discontinuations occurred. There were no major imbalances in adverse events or laboratory findings, or evidence of systemic JAK inhibition.

CONCLUSIONS

GDC-0214, an inhaled JAK inhibitor, caused dose-dependent reductions in Feno in mild asthma and was well tolerated without evidence of systemic toxicity.

Small molecule approaches to treat autoimmune and inflammatory diseases (Part I): Kinase inhibitors

Autoimmune and inflammatory diseases place a huge burden on the healthcare system. Small molecule (SM) therapeutics provide much needed complementary treatment options for these diseases. This digest series highlights the latest progress in the discovery and development of safe and efficacious SMs to treat autoimmune and inflammatory diseases with each part representing a class of SMs, namely: 1) protein kinases; 2) nucleic acid-sensing pathways; and 3) soluble ligands and receptors on cell surfaces. In this first part of the series, the focus is on kinase inhibitors that emerged between 2018 and 2020, and which exhibit increased target and tissue selectivity with the aim of increasing their therapeutic index.

Potential of B-cell-targeting therapy in overcoming multidrug resistance and tissue invasiveness associated with P-glycoprotein expressing-B cell compartments

Rheumatoid arthritis (RA) is a systemic autoimmune mediated inflammatory disease characterized by progressive joint damage and extra-articular organ manifestations. Among the effector pathways and cells involved in the development of RA, activated B cells play a pivotal role in the pathological process of RA. P-glycoprotein (P-gp), a member of ATP-binding cassette transporters, is induced on the cell membrane by certain stimuli. P-gp transports various drugs from the cytoplasm to the cell exterior, resulting in the development of drug resistance. P-gp expression on B cells appears in patients with RA as the disease activity increases, and treatment of these patients' results in modification of over-expression of P-gp on activated B cells. Evidence suggests that P-gp expressing-activated B cells play important roles in the pathogenesis and treatment resistance in RA through the efflux of intracellular drugs and progression of infiltration in inflammatory lesions. Therapies designed to target activated B cells might overcome refractory RA. Identification of the subsets of peripheral activated B cells that express P-gp in RA patients might help the selection of suitable treatment strategy.

Beyond type 2 cytokines in asthma - new insights from old clinical trials

Introduction: Human asthma is a heterogeneous disorder on molecular, pathological, and clinical levels. The paradigm of asthma as an allergic process driven by type 2 cytokines and mediators has led to targeted biologic therapies resulting in some clinical benefit in patient subsets. However, some patient subsets and clinical manifestations do not benefit from these interventions, thus redefining unmet needs. Clinical studies of type 2 directed therapies have identified new targets under investigation in clinical development; these include epithelial alarmins, non-type 2 cytokines, cytokine receptor signaling, mast cells and neuroinflammation.Areas covered: We consider lessons learned concerning asthma pathogenesis from observational studies and clinical trials of biologic agents that target type 2 mediators. We also provide a perspective on emerging therapeutic hypotheses to target processes independent of or orthogonal to type 2 inflammation in asthma.Expert opinion: Type 2 inflammation is continuous, not discrete, and is likely a modifier of underlying dysregulated airway physiology. Non-type 2 inflammatory mediators (e.g., IL17, IL6, IFNs), microbiome, alarmins (e.g., TSLP, IL33), mast cells and sensory neurons may represent orthogonal targets to type 2 mediators. There is a need to better match targets and outcome measures in biologically defined patient populations to appropriately test hypotheses in the clinic.