An update on emerging drugs for asthma

Treating severe asthma: Targeting the IL-5 pathway

Severe asthma is a heterogeneous disease with different phenotypes based on clinical, functional or inflammatory parameters. In particular, the eosinophilic phenotype is associated with type 2 inflammation and increased levels of interleukin (IL)-4, IL-5 and IL-13). Monoclonal antibodies that target the eosinophilic inflammatory pathways (IL-5R and IL-5), namely mepolizumab, reslizumab, and benralizumab, are effective and safe for severe eosinophilic asthma. Eosinophils threshold represents the most indicative biomarker for response to treatment with all three monoclonal antibodies. Improvement in asthma symptoms scores, lung function, the number of exacerbations, history of late-onset asthma, chronic rhinosinusitis with nasal polyposis, low oral corticosteroids use and low body mass index represent predictive clinical markers of response. Novel Omics studies are emerging with proteomics data and exhaled breath analyses. These may prove useful as biomarkers of response and non-response biologics. Moreover, future biomarker studies need to be undertaken in paediatric patients affected by severe asthma. The choice of appropriate biologic therapy for severe asthma remains challenging. The importance of finding biomarkers that can predict response continuous an open issue that needs to be further explored. This review describes the clinical effects of targeting the IL-5 pathway in severe asthma in adult and paediatric patients, focusing on predictors of response and non-response.

Protective Effect of S-Allyl Cysteine Against Neonatal Asthmatic Rats

S-Allyl cysteine (SAC), an organic compound and a natural constituent of Allium sativum, commonly known as garlic have been consumed in routine foods are known to possess various biological activities. Nevertheless, scientific evidence on the protective effect of SAC against neonatal asthmatic rats is not available. Hence, the present study aimed at investigating the anti-asthmatic activity of SAC in neonatal asthmatic rats using Wistar rats. The study conducted in 4 groups consists of normal control rats, asthma-induced, asthma animals administered with SAC (25 mg/kg), and SAC control. At the end of the experimental period, inflammatory cells in bronchoalveolar lavage fluid (BALF), inflammatory markers, fibrinogen level, activated partial thromboplastin time, coagulation factor activity, and histopathology were elucidated. The current investigation exhibits that SAC significantly reduced the total leukocytes, with restored fibrinogen level, and activated partial thromboplastin time. In addition, the levels of inflammatory cytokines such as TNF-α (tumor necrosis factor- α), IL-6 (Interleukin 6), and IL-1β have also attenuated in SAC treated animals. Furthermore, the mRNA expression levels of COX2 (cyclooxygenase-2), MCP-1 (monocyte chemoattractant protein-1), RANTES (regulated upon activation, normal T cell expressed and secreted), and eotaxin were reduced in SAC treated animals. Treatment of rats with SAC significantly reduced inflammation and eosinophil infiltration in the lungs. These results suggest that SAC exert protection in neonatal asthmatic rats suffering from acute or chronic inflammation by inducing anti-inflammatory and cell-protective responses.

Are biological drugs effective and safe in older severe asthmatics?

INTRODUCTION

The treatment of asthma in older ages follows the recommendations of international guidelines for the management of asthma in younger ages, although older age has always represented an exclusion criterion for eligibility to pharmacological trials. This poses a clinical challenge when deciding whether elderly severe asthmatics are candidates for biological drugs.

AREAS COVERED

The current article has a narrative structure to review the current literature on efficacy and safety of novel pharmacological drugs against immunoglobulins and interleukins that mediate and orchestrate the main inflammatory pathways in severe asthma, in order to explore whether older subjects (i.e. > 65 years of age) are included.

EXPERT OPINION

Asthma in older ages is not a rare entity, and loss of symptom control is common in most advanced ages. Current evidence from randomized clinical trials (RCTs) on the safety of biological drugs in elderly asthmatics is scarce and does not allow drawing definitive conclusions. An urgent call for studies specifically designed for elderly populations is needed, with the purpose to assess the efficacy and safety of target biological therapies in advanced ages. We envision the design of large multi-center clinical trials to decide whether and when geriatric population could benefit from biological therapies.

Overlapping Effects of New Monoclonal Antibodies for Severe Asthma

Among the monoclonal antibodies (mAbs) developed for severe asthma treatment, three have already been marketed. Omalizumab was the first, more than 10 years ago; today, mepolizumab and reslizumab are also available in the European Union and the US. Omalizumab blocks free immunoglobulin E (IgE), mepolizumab and reslizumab block an interleukin (IL-5). In the near future, dupilumab and benralizumab are expected to emerge as two new alternatives. Benralizumab blocks the receptor for IL-5 (IL5-Rα) and has a direct cytotoxic effect on eosinophils, and dupilumab blocks the α-unit of the heterodimeric receptor for IL-4 and IL-13 (IL-4Rα); as a result, dupilumab can block both IL-4 and IL-13. The purpose of this manuscript is to present the pathophysiology of some immunological aspects of severe asthma, describe the adaptive and innate immunity arms as well as their interrelations (stressing the subordination of the adaptive arm to the innate arm), outline the pharmacologic effects of these mAbs, clarify the overlapping effects of the different mAbs, and discuss the differences between mAbs based on their target molecules. Based on the data presented, I propose omalizumab for patients with an allergic phenotype regardless of their peripheral eosinophilic count, and anti-IL-5 as an alternative in allergic patients with blood eosinophilia in which omalizumab has failed; anti-IL5 for patients with an eosinophilic phenotype and omalizumab as an alternative in patients in whom anti-IL5 fails and IgE ≥30 IU/mL (compassionate use). Omalizumab is also proposed for patients with severe chronic asthma allergic to seasonal allergens.

Broad Th2 neutralization and anti-inflammatory action of pentosan polysulfate sodium in experimental allergic rhinitis

Background

Th2 cytokines like interleukin‐4, ‐5, and ‐13 are regarded as important drivers of the immunopathology underlying allergic rhinitis (AR) and asthma. The present study explores the capacity of pentosan polysulfate sodium (PPS), a semi‐synthetic heparin‐like macromolecular carbohydrate, to bind Th2 cytokines and exert biological neutralization in vitro, as well as anti‐inflammatory actions in vivo.

Methodology

The capacity of PPS to bind recombinant Th2 cytokines was tested with surface plasmon resonance (SPR) technology and biological Th2 neutralization was assessed by Th2‐dependent proliferation assays. The in vivo anti‐inflammatory action of PPS was studied using a validated Guinea‐pig model of AR.

Results

Binding studies revealed a strong and specific binding of PPS to IL‐4, IL‐5, and IL‐13 with IC values suggesting as stronger cytokine binding than for heparin. Cytokine binding translated to a biological neutralization as PPS dose dependently inhibited Th2‐dependent cell proliferation. Topical administration of PPS 30 min prior to nasal allergen challenge of sensitized animals significantly reduced late phase plasma extravasation, luminal influx of eosinophils, neutrophils, and total lavage leukocytes. Similar, albeit not statistically secured, effects were found for tissue leukocytes and mucus hyper‐secretion. The anti‐inflammatory effects of PPS compared favorably with established topical nasal steroid treatment.

Conclusion

This study points out PPS as a potent Th2 cytokine‐binding molecule with biological neutralization capacity and broad anti‐inflammatory effects in vivo. As such PPS fulfills the role as a potential candidate molecule for the treatment of AR and further studies of clinical efficacy seems highly warranted.

Benralizumab for the treatment of asthma

INTRODUCTION

The classification of asthma into phenotypes and endotoypes allows for the use of targeted therapies, including three biologics which target interleukin 5 (IL-5) signaling in eosinophilic asthma. Areas covered: As of December 2016, two monoclonal antibodies, mepolizumab and reslizumab, are approved by U.S. Food and Drug Administration and one, benralizumab, is in clinical development. Two phase 3 trials for benralizumab, SIROCCO and CALIMA, were published in September 2016. Although there are no direct comparisons among these three anti-IL-5 therapies, the goal of this review is to summarize the current data and discuss their potential similarities and differences, with a focus on benralizumab. Expert commentary: Compared to mepolizumab and reslizumab, the possible advantages of benralizumab are less frequent dosing and a potential to reduce exacerbations irrespective of the blood eosinophil count. Some improvements in asthma symptom scores and quality of life occur with all three biologics, but the clinical meaningfulness of these improvements is less clear. A more defined reference range for eosinophil levels is necessary to determine which subjects will best benefit from these medications. Until quality randomized controlled trials directly compare the three, choosing among them for the treatment of eosinophilic asthma remains difficult.

Treatment response with mepolizumab in severe eosinophilic asthma patients with previous omalizumab treatment

Background

We performed post hoc analyses to evaluate the effect of humanized monoclonal antibody mepolizumab in patients with severe eosinophilic asthma previously treated with omalizumab.

Methods

Data were collected from two randomized double‐blind, placebo‐controlled studies: MENSA (NCT01691521: 32‐week treatment phase) and SIRIUS (NCT01691508: 24‐week treatment phase). Active treatment was 75 mg intravenous mepolizumab (MENSA) or 100 mg subcutaneous mepolizumab (MENSA, SIRIUS). Patients had evidence of eosinophilic inflammation ≥150 cells/μl (at screening) or ≥300 cells/μl (during the previous year). Primary outcomes were the rate of exacerbations (MENSA) and the percentage reduction in oral corticosteroid (OCS) dose (SIRIUS). Other outcomes included lung function (forced expiratory volume in 1 s and morning peak expiratory flow), Asthma Control Questionnaire (ACQ‐5), St George's Respiratory Questionnaire (SGRQ) scores, and safety.

Results

Overall, 576 patients were included from MENSA and 135 from SIRIUS, with 13% and 33% previously receiving omalizumab, respectively. In MENSA, mepolizumab reduced the rate of exacerbations by 57% (prior omalizumab) and 47% (no prior omalizumab) vs placebo. In SIRIUS, reductions in OCS use were comparable regardless of prior omalizumab use. Despite reducing chronic OCS use, mepolizumab also resulted in similar reductions in exacerbation rate relative to placebo in both subgroups. Asthma control and quality of life improved with mepolizumab vs placebo in both studies independent of prior omalizumab use, as shown by ACQ‐5 and SGRQ scores. Adverse events were also comparable irrespective of prior omalizumab use.

Conclusions

These post hoc analyses indicate that patients with severe eosinophilic asthma respond positively to mepolizumab regardless of prior use of omalizumab.

Targeting the Src Homology 2 (SH2) Domain of Signal Transducer and Activator of Transcription 6 (STAT6) with Cell-Permeable, Phosphatase-Stable Phosphopeptide Mimics Potently Inhibits Tyr641 Phosphorylation and Transcriptional Activity

Signal transducer and activator of transcription 6 (STAT6) transmits signals from cytokines IL-4 and IL-13 and is activated in allergic airway disease. We are developing phosphopeptide mimetics targeting the SH2 domain of STAT6 to block recruitment to phosphotyrosine residues on IL-4 or IL-13 receptors and subsequent Tyr641 phosphorylation to inhibit the expression of genes contributing to asthma. Structure-affinity relationship studies showed that phosphopeptides based on Tyr631 from IL-4Rα bind with weak affinity to STAT6, whereas replacing the pY+3 residue with simple aryl and alkyl amides resulted in affinities in the mid to low nM range. A set of phosphatase-stable, cell-permeable prodrug analogues inhibited cytokine-stimulated STAT6 phosphorylation in both Beas-2B human airway cells and primary mouse T-lymphocytes at concentrations as low as 100 nM. IL-13-stimulated expression of CCL26 (eotaxin-3) was inhibited in a dose-dependent manner, demonstrating that targeting the SH2 domain blocks both phosphorylation and transcriptional activity of STAT6.

Anti-IL-4/-13 based therapy in asthma

It is recognised that airway inflammation is key to asthma pathogenesis. Biopharmaceutical approaches have identified new therapies that target key cells and mediators that drive the inflammatory responses in the asthmatic lung. Such an approach resulted in the development of biologics targeted at inhibition of IL-4, IL-5 and IL-13. However, early clinical trials with these biologics in patients with asthma were for the most part disappointing even though they were highly effective in animal models of asthma. It is becoming apparent that significant clinical effects with anti-cytokine-based biologic therapies are more likely in carefully selected patient populations that take asthma phenotypes into account. The development of discriminatory biomarkers and genetic profiling may aid identification of such patients with asthma. This review is an update of the evidence demonstrating the effectiveness or otherwise of the targeting of the TH2 cytokines IL-4 and IL-13 with biologics in patients with asthma.

The potential effect of the angiotensin II receptor blocker telmisartan in regulating OVA-induced airway remodeling in experimental rats

BACKGROUND

Bronchial asthma is a true ascending clinical problem. Angiotensin II is now accused to be potentially implicated in its pathogenesis, being a potent pro-inflammatory mediator with remodeling effects.

OBJECTIVE

This study aims to evaluate the possible protective effect of telmisartan, an angiotensin II receptor blocker, on experimentally-induced bronchial asthma.

METHODS

Animals were divided into 5 groups; a normal control group, an asthma control group, a reference treatment group, receiving dexamethasone, and two treatment groups, receiving telmisartan in two dose levels. Bronchial asthma was induced by intraperitoneal sensitization followed by intranasal challenge with ovalbumin (OVA). Test agents were administered prior to each intranasal OVA challenge. Lung function tests, namely tidal volume (TV) and peak expiratory flow rate (PEF) were assessed 1h after the last challenge. One day after the last challenge, absolute eosinophil counts (AEC) in blood and bronchoalveolar lavage fluids (BALF) were assessed. Serum immunoglobulin E (IgE) as well as BALF total nitrate/nitrite (NOx) were assessed. Oxidative and inflammatory biomarkers, namely lung tissue superoxide dismutase (SOD), glutathione reduced (GSH), tumor necrosis factor-alpha (TNF-α) and interleukin-5 (IL-5), were also assessed, in addition to histopathological study.

RESULTS

Telmisartan administration in both doses significantly improved TV, PEF, AEC, IgE, NOx, GSH, SOD, TNF-α and IL-5 values compared to asthma control values. Histopathological study strongly supported the results of biochemical estimations, particularly regarding airway remodeling.

CONCLUSION

These results suggest that telmisartan may have potential protecting effects against experimental bronchial asthma, probably due to its bronchodilator, antioxidant and anti-inflammatory effects.

ISU201 enhances the resolution of airway inflammation in a mouse model of an acute exacerbation of asthma

Glucocorticoids are commonly used for treating asthma and its exacerbations but have well-recognised adverse effects and are not always effective. Few alternative treatments exist. Using a murine model of an acute exacerbation of asthma, we assessed the ability of ISU201, a novel protein drug, to suppress the inflammatory response when administered after induction of an exacerbation. Sensitised mice were chronically challenged with a low mass concentration of aerosolised ovalbumin, and then received a single moderate-level challenge to simulate an allergen-induced exacerbation. ISU201 was administered to mice 2 and 8 hours later, while pulmonary inflammation and expression of mRNA for chemokines and proinflammatory cytokines were assessed after 4, 12, and 24 hours. Relative to vehicle-treated controls, ISU201 suppressed accumulation of pulmonary neutrophils and eosinophils, while accelerating the decline in CXCL1, TNF-α, and IL-6 in lavage fluid and lung tissue. ISU201 significantly reduced peak expression of mRNA for the chemokines Cxcl9 and Cxcl10, the adhesion molecules Icam1 and Vcam1, and the proinflammatory cytokines Il1b, Il12p40, and Csf1. The ability of ISU201 to promote resolution of inflammation suggests that it may have potential as an alternative to glucocorticoids in the management of asthma, including when administered after the onset of an acute exacerbation.

Oral glucocorticoid-sparing effect of mepolizumab in eosinophilic asthma

BACKGROUND

Many patients with severe asthma require regular treatment with oral glucocorticoids despite the use of high-dose inhaled therapy. However, the regular use of systemic glucocorticoids can result in serious and often irreversible adverse effects. Mepolizumab, a humanized monoclonal antibody that binds to and inactivates interleukin-5, has been shown to reduce asthma exacerbations in patients with severe eosinophilic asthma.

METHODS

In a randomized, double-blind trial involving 135 patients with severe eosinophilic asthma, we compared the glucocorticoid-sparing effect of mepolizumab (at a dose of 100 mg) with that of placebo administered subcutaneously every 4 weeks for 20 weeks. The primary outcome was the degree of reduction in the glucocorticoid dose (90 to 100% reduction, 75 to less than 90% reduction, 50 to less than 75% reduction, more than 0 to less than 50% reduction, or no decrease in oral glucocorticoid dose, a lack of asthma control during weeks 20 to 24, or withdrawal from treatment). Other outcomes included the rate of asthma exacerbations, asthma control, and safety.

RESULTS

The likelihood of a reduction in the glucocorticoid-dose stratum was 2.39 times greater in the mepolizumab group than in the placebo group (95% confidence interval, 1.25 to 4.56; P=0.008). The median percentage reduction from baseline in the glucocorticoid dose was 50% in the mepolizumab group, as compared with no reduction in the placebo group (P=0.007). Despite receiving a reduced glucocorticoid dose, patients in the mepolizumab group, as compared with those in the placebo group, had a relative reduction of 32% in the annualized rate of exacerbations (1.44 vs. 2.12, P=0.04) and a reduction of 0.52 points with respect to asthma symptoms (P=0.004), as measured on the Asthma Control Questionnaire 5 (in which the minimal clinically important difference is 0.5 points). The safety profile of mepolizumab was similar to that of placebo.

CONCLUSIONS

In patients requiring daily oral glucocorticoid therapy to maintain asthma control, mepolizumab had a significant glucocorticoid-sparing effect, reduced exacerbations, and improved control of asthma symptoms. (Funded by GlaxoSmithKline; SIRIUS ClinicalTrials.gov number, NCT01691508.).

Janus kinase 1/3 signaling pathways are key initiators of TH2 differentiation and lung allergic responses

BACKGROUND

Janus kinases (JAKs) are regulators of signaling through cytokine receptors. The importance of JAK1/3 signaling on TH2 differentiation and development of lung allergic responses has not been investigated.

OBJECTIVE

We sought to examine a selective JAK1/3 inhibitor (R256) on differentiation of TH subsets in vitro and on development of ovalbumin (OVA)-induced airway hyperresponsiveness (AHR) and inflammation in an experimental model of asthma.

METHODS

A selective JAK1/3 inhibitor was used to assay the importance of this pathway on induction of TH1, TH2, and TH17 differentiation in vitro. In vivo, the effects of inhibiting JAK1/3 signaling were examined by administering the inhibitor during the sensitization or allergen challenge phases in the primary challenge model or just before provocative challenge in the secondary challenge model. Airway inflammation and AHR were examined after the last airway challenge.

RESULTS

In vitro, R256 inhibited differentiation of TH2 but not TH1 or TH17 cells, which was associated with downregulation of signal transducer and activator of transcription (STAT) 6 and STAT5 phosphorylation. However, once polarized, TH2 cells were unaffected by the inhibitor. In vivo, R256 administered during the OVA sensitization phase prevented the development of AHR, airway eosinophilia, mucus hypersecretion, and TH2 cytokine production without changes in TH1 and TH17 cytokine levels, indicating that selective blockade of TH2 differentiation was critical. Inhibitor administration after OVA sensitization but during the challenge phases in the primary or secondary challenge models similarly suppressed AHR, airway eosinophilia, and mucus hypersecretion without any reduction in TH2 cytokine production, suggesting the inhibitory effects were downstream of TH2 cytokine receptor signaling pathways.

CONCLUSIONS

Targeting the TH2-dependent JAK/STAT activation pathway represents a novel therapeutic approach for the treatment of asthma.

Puerarin attenuates ovalbumin-induced lung inflammation and hemostatic unbalance in rat asthma model

Aim. We aimed to investigate and evaluate the preventive activity of puerarin on the ovalbumin-induced asthma rat model. Materials and Methods. Male Wistar rats were sensitized intraperitoneally on days 0, 7, and 14 and challenged to ovalbumin intratracheally on day 21. Groups of sensitized rats were treated randomly either with placebo, puerarin, dexamethasone, or puerarin combined with dexamethasone, from days 15 to 20. Inflammatory markers, including cell counts in bronchoalveolar lavage fluid (BALF), inflammatory cytokines, histopathology, and coagulation parameters, such as coagulation tests and the activity of coagulation factors, were analyzed. Results. Puerarin significantly inhibited the recruitment of inflammatory cells in BALF and lung tissue. At the same time, the release of IL-4, IL-10, and IFN-γ in serum and the expression of mRNAs in lung tissue homogenate were changed by puerarin. Administration of puerarin also effectively rectified the coagulation disorder in asthmatic rats, such as prothrombin time (PT) (P < 0.01), thrombin time (TT) (P < 0.05), fibrinogen (FIB) (P < 0.01),the activity of factor II (FII) (P < 0.01), the activity of factor V (FV) (P < 0.05), the activity of factor VII (FVII) (P < 0.05), the activity of factor X (FX) (P < 0.05), the activity of factor VIII (FVIII) (P < 0.01), the activity of factor IX (FIX) (P < 0.05), and the activity of factor XII (FXII) (P < 0.05). Conclusions. Our results provide a clue that puerarin was useful for the preventive of allergic airway disease in rodents.

Chemokines mediate ethanol-induced exacerbations of murine cockroach allergen asthma

Asthma imposes considerable patient and economic burdens, with the most severe cases causing the greatest affliction. Identifying stimuli that worsen asthma severity is an essential step to controlling both disease morbidity and the lessening economic impact. This study provides the first mechanistic investigation into how acute ethanol exposure will increase asthma severity in a murine model of mild cockroach allergen (CRA)-induced asthma. Outbred mice were sensitized to induce mild allergic asthma, with intratracheal CRA exposures on days 0 and 14. On day 21 mice were gavaged with water or 32% ethanol, and the third allergen exposure was given 30 min post-gavage. Asthmatic responses were measured at several time-points up to 42 h after the third allergen challenge. Ethanol-gavaged mice showed increased asthma severity within 90 min post-allergen challenge, with exacerbations lasting for 24 h. Ethanol caused greater airways obstruction, including an eightfold increase in epithelial cell mucin and increased mucus plugs, resulting in a 50% reduction in bronchiole patency. Ethanol gavage also induced significant increases in airways hyperreactivity. While T helper type 1 (Th1) and Th2 cytokines were not altered by ethanol gavage, pulmonary neutrophil and eosinophil recruitment were augmented. This increase was associated with increased chemokine production. Administration 2 h prior to ethanol gavage of a neutralizing antibody cocktail to keratinocyte-derived chemokine, macrophage inflammatory protein-2, eotaxin-1 and eotaxin-2 prevented ethanol-induced eosinophil recruitment and airways hyperreactivity. These data provide evidence that acute alcohol exposure immediately prior to a mild allergen-triggered asthmatic episode will exacerbate asthma severity mediated by increased production of chemokines.