A critical appraisal of methods used in early clinical development of novel drugs for the treatment of asthma

Phenotyping patients with chronic cough: Evaluating the ability to predict the response to anti-inflammatory therapy

BACKGROUND

Whether the fraction of exhaled nitric oxide (FeNO) measurement can predict the response to anti-inflammatory treatment in chronic cough is unknown.

OBJECTIVE

To explore whether the effectiveness of treatment with 10 mg of montelukast or 20 mg of prednisolone in patients with chronic cough is predicted by FeNO level.

METHODS

In this randomized, open-label, controlled pilot study conducted in the Clinical Trial Unit in Castle Hospital in the United Kingdom, 50 nonsmoking patients with a cough that lasted more than 8 weeks were sequentially enrolled in the study. Thirty patients with high FeNO levels (≥30 ppb) were randomized in a 1:1 ratio to receive 10 mg of montelukast or 20 mg of prednisolone for 2 weeks followed by 10 mg of montelukast for 2 weeks. Twenty patients with a low FeNO level (≤20 ppb) received 10 mg of montelukast. The primary objective was to determine the effectiveness of treatment on 24-hour cough counts.

RESULTS

The 24-hour cough counts decreased in both groups by approximately 50% (P < .005), indicating that FeNO did not predict treatment response. However, it was a good marker for eosinophilic inflammation with a high degree of correlation with blood and sputum eosinophilia (P < .001).

CONCLUSION

These results suggest that prior investigation may not predict response to anti-inflammatory treatment, which may be consequent on localized leukotriene-mediated inflammation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02479074.

Does FeNO Predict Clinical Characteristics in Chronic Cough?

Purpose

To evaluate whether exhaled nitric oxide measurement can facilitate in the assessment of chronic cough patients based on their airway inflammatory phenotype.

Methods

We have studied consecutive patients attending a specialist cough clinic. 30 patients with high FeNO (> 30 ppb) and 20 patients with low FeNO (< 20 ppb) were recruited.

Results

There was a significant correlation between FeNO, B-Eos and sputum eosinophil count (p < 0.001). The number of recorded coughs in 24 h and HARQ scores were significantly (p < 0.05) higher in patients with a low FeNO. In contrast to the high FeNO group (48%), the greater proportion of these patients were women (90%). LCQ scores were worse in the low FeNO group but it was not significant.

Conclusion

A strong relationship between FeNO, blood eosinophils and sputum eosinophils confirming phenotypic identity was observed. Whether the observed gender disparity accounts for the different cough frequency characteristics is unknown.

The Emerging Role of The Eosinophil and Its Measurement in Chronic Cough

Although the aetiology of chronic cough in guidelines is clearly stated as asthma and related syndromes, gastro-oesophageal reflux disease (GORD), and upper airways disease, the inflammatory mechanisms underlying these conditions differ. Recent studies on asthma have increasingly focused on its molecular phenotypes instead of clinical characteristics. Here, we proposed the hypothesis that divides cough into two groups; the eosinophilic and neutrophilic. This division will enhance our ability to recognise the type of airway inflammation which, as a consequence will lead us to more targeted and personalized treatment approaches.

Bronchial inflammation in seasonal allergic rhinitis with or without asthma in relation to natural exposure to pollen allergens

BACKGROUND

Nasal inflammation in allergic rhinitis enhances bronchial Th2 driven inflammation and development of asthma. We assessed bronchial inflammation induced by natural allergen exposure during pollen season in patients with pollinosis with or without asthma to show the intensity of inflammation in asthma and rhinitis and possible persistence of inflammation in periods without allergen exposure.

METHODS

Sputum was induced in 52 patients with seasonal allergic rhinitis without asthma, 38 patients with seasonal allergic rhinitis and seasonal asthma and 23 healthy volunteers. Sampling was performed 6-8 weeks before the expected beginning of symptoms, during symptomatic period and 6-8 weeks after the end of symptoms. Sputum ECP was measured by means of chemi-luminiscent immunometric assay and sputum cell counts were assessed by classical staining and immunocytochemistry.

RESULTS

Sputum eosinophils were on the whole higher in both asthma and rhinitis compared to controls (p<0.001, p=0.003). The rise of eosinophils during pollen season compared with values out of pollen season was significant in asthma (classical staining) (p=0.014) and slightly apparent in rhinitis (immunocytochemistry) (p=0.073). The seasonal rise of sputum ECP was observed only in rhinitis (p=0.006).

CONCLUSIONS

Inflammation of the lower airway in patients with allergic rhinitis with and without asthma has been confirmed by means of both sputum eosinophil count and sputum ECP level. Persistent inflammation of lower airway in periods without allergen exposure was proven in seasonal asthma. This may have implications for the therapy of seasonal allergic rhinitis with and without asthma in terms of promoting long-term anti-inflammatory treatment.

Reproducibility of sputum differential cell counts is not affected by squamous epithelial cells

OBJECTIVE

Induced sputum is used to assess markers of inflammation in asthmatic individuals, and sputum cell differential counts provide an outcome to evaluate the presence, type, and degree of inflammation in the airways. Contamination of sputum slides with squamous epithelial cells (SECs) has been reported to adversely affect the reproducibility of sputum cell differential counts; however, this has not been studied in a controlled manner. Excluding sputum slides because of excessive squamous cell contamination can be problematic resulting in under-powering of studies. The aim of this study is to evaluate the effect of SEC contamination and cell dispersion on the reproducibility of differential counts of sputum cells prepared on glass slides.

STUDY DESIGN

A total of 33 sputum samples were induced from 11 subjects with mild asthma under baseline conditions and following an allergen inhalation challenge. Mucoid and salivary portions of each sample were divided and processed in parallel. To evaluate the effect of increasing the proportion of SEC and to evaluate the effect of increasing the number of leukocytes per high power field (HPF), four slides with varying leukocyte numbers and SEC percentages were prepared from each sample by combining and adjusting the volume of cell suspensions derived from mucous and saliva. The four slides were prepared to fall in the following categories: (A) 50 cells/HPF and <20% SEC; (B) 50 cells/HPF and >20% SEC; (C) 100 cells/HPF and <20% SEC; and (D) 100 cells/HPF and >20% SEC. All slides were blinded and counted twice by an experienced observer, and twice by an inexperienced observer.

RESULTS

The differential cell counts for eosinophils, macrophages, and neutrophils were highly reproducible under all conditions when enumerated by an experienced observer (ICC > 0.9), and furthermore, SEC contamination did not affect ICC when differential counts were enumerated by an inexperienced observer (ICC > 0.8).

CONCLUSION

Our results demonstrate that slides containing SECs, up to 40% in this study, have reproducible differential cell counts.

Atopic dermatitis and the atopic march: what is new?

Objective. In this paper the authors review the management of atopic dermatitis (AD) and the association between AD and allergic respiratory diseases. Data Sources. PubMed databases, researching articles in the last 15 years. Results. Studies about atopic march are cross-sectional population studies at different ages. They show that the most important predisposing factor for atopy is a decrease of the filaggrin's expression. Conclusions. The most modern theories seem to show that the most important factor which starts the atopic march is represented by an impaired epidermal barrier. It causes an increase in skin permeability to allergens that could induce sensitization even in the airways. The major predisposing factor is a primary inherited epithelial barrier defect resulting from filaggrin gene mutation, but other factors may play a role in this complex mechanism. Further studies are needed to focus on AD treatment and preventive strategies.

Biomarkers in asthma and allergic rhinitis

A biological marker (biomarker) is a physical sign or laboratory measurement that can serve as an indicator of biological or pathophysiological processes or as a response to a therapeutic intervention. An applicable biomarker possesses the characteristics of clinical relevance (sensitivity and specificity for the disease) and is responsive to treatment effects, in combination with simplicity, reliability and repeatability of the sampling technique. Presently, there are several biomarkers for asthma and allergic rhinitis that can be obtained by non-invasive or semi-invasive airway sampling methods meeting at least some of these criteria. In clinical practice, such biomarkers can provide complementary information to conventional disease markers, including clinical signs, spirometry and PC(20)methacholine or histamine. Consequently, biomarkers can aid to establish the diagnosis, in staging and monitoring of the disease activity/progression or in predicting or monitoring of a treatment response. Especially in (young) children, reliable, non-invasive biomarkers would be valuable. Apart from diagnostic purposes, biomarkers can also be used as (surrogate) markers to predict a (novel) drug's efficacy in target populations. Therefore, biomarkers are increasingly applied in early drug development. When implementing biomarkers in clinical practice or trials of asthma and allergic rhinitis, it is important to consider the heterogeneous nature of the inflammatory response which should direct the selection of adequate biomarkers. Some biomarker sampling techniques await further development and/or validation, and should therefore be applied as a "back up" of established biomarkers or methods. In addition, some biomarkers or sampling techniques are less suitable for (very young) children. Hence, on a case by case basis, a decision needs to be made what biomarker is adequate for the target population or purpose pursued. Future development of more sophisticated sampling methods and quantification techniques, such as--omics and biomedical imaging, will enable detection of adequate biomarkers for both clinical and research applications.

Montelukast in the treatment of asthma and beyond

Asthma is a chronic inflammatory disease affecting over 300 million people worldwide. The common association with allergic rhinitis and the presence of proinflammatory cells and mediators in the circulation of patients qualify asthma as a systemic disease. This characteristic and the fact that the gold-standard therapy for persistent asthma, inhaled corticosteroids, cannot suppress all components of airway inflammation and fail to adequately penetrate into the small airways, warrant the quest for effective systemic anti-asthma therapies. This review describes the most important controlled studies of montelukast, a once-daily leukotriene receptor antagonist, in asthma and allergic rhinitis in both adults and children. Montelukast is a systemically active drug with a targeted, dual mechanism of action, acting both as a bronchodilator and anti-inflammatory. In patients of all ages, montelukast has shown a favorable safety profile and was well-tolerated. Both as monotherapy or in combination with inhaled corticosteroids, montelukast produced clinically relevant improvements in asthma-related parameters, including symptoms, lung function parameters, quality of life and the number of asthma exacerbations. Furthermore, bronchoprotective effects have been reported both against specific and nonspecific bronchoactive stimuli. Similarly, in patients with allergic rhinitis, montelukast produced substantial improvements in symptoms and quality of life. Long-term studies aimed to determine its effects on airway remodeling are still lacking.

Cleaved secretory leucocyte protease inhibitor as a biomarker of chymase activity in allergic airway disease

BACKGROUND

Secretory leucocyte protease inhibitor (SLPI), which is present in many physiological fluids including saliva, sputum and nasal discharge, is the most effective inhibitor of chymase. Previously, we demonstrated that chymase is able to cleave SLPI and that the cleaved portion, cSLPI, is a biomarker of chymase activity.

OBJECTIVE

We investigated the potential of cSLPI as a biomarker of chymase activity in subjects with allergic rhinitis (AR) and asthmatic airway disease.

METHODS

Baseline sputum samples were collected from atopic asthmatics and healthy controls (HC). Nasal lavages (NAL) were performed in subjects with AR both at baseline and following a nasal challenge with allergen or placebo. Levels of cSLPI and chymase were determined by Western analysis, and tryptase and alpha-2 macroglobulin were measured by immunoassay.

RESULTS

As compared with HC, asthmatics showed a significant increase in baseline cSLPI/total SLPI ratios and an increase in chymase levels. There was a high correlation of cSLPI/SLPI ratios to chymase levels in normal individuals and untreated asthmatics. In the NAL of patients with AR, as compared with placebo, allergen challenge increased inflammatory biomarkers, including cSLPI/SLPI ratios, chymase levels, tryptase levels and alpha2-macroglobulin levels. Correlations were observed between cSLPI/SLPI ratios and chymase levels and cSLPI/SLPI ratios and alpha2-macroglobulin levels; no correlation was seen between cSLPI/SLPI ratios and tryptase levels.

CONCLUSION

Our data indicate that cSLPI reflects chymase activity in AR and asthma. Hence, cSLPI may serve as a biomarker for disease activity and for monitoring the efficacy of novel anti-inflammatory treatments in chymase-mediated diseases.

Comparison of exhaled nitric oxide measurements between NIOX MINO electrochemical and Ecomedics chemiluminescence analyzer

BACKGROUND

Exhaled nitric oxide (eNO) is an established, noninvasive biomarker of active airway inflammation in (atopic) asthma. Treatment with anti-inflammatory therapy, such as inhaled corticosteroids, effectively decreases eNO levels. The NIOX MINO (MINO) is a hand-held, relatively inexpensive, electrochemical device that has been shown to yield comparable eNO measurements to the NIOX stationary unit.

AIM

To compare measurements of MINO with another widely used and validated stationary chemiluminescence analyzer, the Ecomedics (ECO).

METHODS

We performed subsequent eNO measurements on ECO and MINO in 50 subjects (19 healthy volunteers, 18 healthy smokers and 13 non-smoking, atopic asthmatics, not on controller therapy) on two visits 4-10 days apart. The mean of three acceptable measurements by ECO and the first acceptable measurement with the MINO were used for analysis.

RESULTS

Both devices yielded reproducible eNO values for all subjects on both visits, with an overall CV of 22.7% (ECO) and 18.3% (MINO). A significant correlation was found between both devices (r=0.97, p<0.0001). Bland-Altman plots showed a high degree of agreement for the entire study population (mean difference MINO vs ECO=-10%; 95% limit of agreement were -36% and +28%) and in the three individual subgroups.

CONCLUSIONS

Exhaled NO values measured with the MINO are reproducible and in agreement with the ECO. Our results add further evidence to the reliability of the MINO and warrant its applicability in research and clinical practice.

Methods used in clinical development of novel anti-asthma therapies

In recent years, it has become increasingly important to get as much as possible information on clinical efficacy already in the early phases of drug development. For proof of concept (POC) studies testing novel anti-inflammatory drugs in asthma, there are several validated exacerbation models, inducing various aspects of the airway inflammation and airway responsiveness. The choice of the appropriate asthma model depends on the drug's targets within the inflammatory process. For adequate assessment of the drug's anti-inflammatory potential, it is crucial to choose adequate (surrogate) biomarkers. Ideally, these should include measures of airway response, central and peripheral airway inflammation and airway hyperresponsiveness. Overall, there are validated non-invasive sampling techniques for the measurement of inflammatory markers in asthma that can be applied as outcome parameters in early clinical trials. If adequately implemented, these measurements can provide early indication of proof of pharmacological and potential therapeutic efficacy-even in first administration to humans.

Nasal nitric oxide: longitudinal reproducibility and the effects of a nasal allergen challenge in patients with allergic rhinitis

BACKGROUND

Exhaled nitric oxide (eNO) is a validated noninvasive marker of airway inflammation in asthma. In patients with allergic rhinitis (AR), increased levels of nasal nitric oxide (nNO) have also been measured. However, the applicability of nNO as a marker of upper airway inflammation awaits validation.

AIM

To test the longitudinal reproducibility of standardized nNO measurements in patients with AR and the effects of nasal allergen challenge.

METHODS

Twenty patients with clinically stable, untreated AR participated in a combined study design. First, reproducibility of nNO was tested over 1, 7, and 14-21 days. Subsequently, the effect of nasal allergen challenge on nNO was studied in a placebo-controlled, parallel design. Nasal NO was measured with a chemoluminescence analyzer. Ten subjects randomly underwent a standardized nasal allergen challenge; 10 subjects received placebo. Response to nasal challenge was monitored by composite symptom scores.

RESULTS

There was a good reproducibility of nNO up to 7 days [coefficient of variation (CV) over 1 (16.45%) and 7 days (21.5%)], decreasing over time [CV (14-21 days): 38.3%]. As compared with placebo, allergen challenge caused a significant increase in symptom scores (P < 0.001), accompanied by a decrease in nNO at 20 min postchallenge (P = 0.001). Furthermore, there was a gradual increase in nNO at 7 h, reaching significance at 24-h postallergen (P = 0.04).

CONCLUSIONS

Similar to eNO in asthma, nNO is a noninvasive marker, potentially suitable to monitor upper airway inflammation following allergen-induced late response. Present data show a good reproducibility of nNO measurements, decreasing over time, probably because of subclinical seasonal influences.