Development of an inhaled anti-TSLP therapy for asthma.

Thymic stromal lymphopoietin (TSLP), an epithelial cell-derived cytokine, acts as a key mediator in airway inflammation and modulates the function of multiple cell types, including dendritic cells and group 2 innate lymphoid cells. TSLP plays a role in asthma pathogenesis as an upstream cytokine, and data suggest that TSLP blockade with the anti-TSLP monoclonal antibody, tezepelumab, could be efficacious in a broad asthma population. Currently approved asthma biologic therapies target allergic or eosinophilic disease and require phenotyping; therefore, an unmet need exists for a therapy that can address Type 2 (T2)-high and T2-low inflammation in asthma. All currently approved biologic treatments are delivered intravenously or subcutaneously; an inhaled therapy route that allows direct targeting of the lung with reduced systemic impact may offer advantages. Currently in development, ecleralimab (CSJ117) represents the first inhaled anti-TSLP antibody fragment that binds soluble TSLP and prevents TSLP receptor activation, thereby inhibiting further inflammatory signalling cascades. This anti-TSLP antibody fragment is being developed for patients with severe uncontrolled asthma despite standard of care inhaled therapy. A Phase IIa proof of concept study, using allergen bronchoprovocation as a model for asthma exacerbations, found that ecleralimab was well-tolerated and reduced allergen-induced bronchoconstriction in adult patients with mild asthma. These results suggest ecleralimab may be a promising, new therapeutic class for asthma treatment.

Eliciting judgements about dependent quantities of interest: The SHeffield ELicitation Framework extension and copula methods illustrated using an asthma case study.

Pharmaceutical companies regularly need to make decisions about drug development programs based on the limited knowledge from early stage clinical trials. In this situation, eliciting the judgements of experts is an attractive approach for synthesising evidence on the unknown quantities of interest. When calculating the probability of success for a drug development program, multiple quantities of interest-such as the effect of a drug on different endpoints-should not be treated as unrelated. We discuss two approaches for establishing a multivariate distribution for several related quantities within the SHeffield ELicitation Framework (SHELF). The first approach elicits experts' judgements about a quantity of interest conditional on knowledge about another one. For the second approach, we first elicit marginal distributions for each quantity of interest. Then, for each pair of quantities, we elicit the concordance probability that both lie on the same side of their respective elicited medians. This allows us to specify a copula to obtain the joint distribution of the quantities of interest. We show how these approaches were used in an elicitation workshop that was performed to assess the probability of success of the registrational program of an asthma drug. The judgements of the experts, which were obtained prior to completion of the pivotal studies, were well aligned with the final trial results.

Development and content validation of a self-completed, electronic Pediatric Asthma Symptom Diary.

BACKGROUND: Childhood asthma is an important unmet need. To date, patient-reported outcome measures (PROMs) for children with asthma have used a combination of caregiver or proxy-reported and self-reported measures. No comprehensive measure is available to assess the severity and impact of daytime and nighttime asthma symptoms and rescue medication use for self-completion by children aged 6-11 years. This study aimed to develop a novel, interactive, electronic Pediatric Asthma Symptom Diary (ePASD) measuring self-reported key symptom severity and proximal impacts of asthma in young children with varying reading ability and disease severity, consistent with US Food and Drug Administration (FDA) PRO guidance and the International Society for Health Economics and Outcomes Research (ISPOR) good research practices. METHODS: A targeted literature review and clinician interviews were undertaken to characterize symptoms and impacts experienced by children with mild-to-severe asthma. Concept elicitation interviews (CEIs) were conducted with 44 children and their caregivers (30 US; 14 UK). Following item and digital application development, the ePASD was assessed for relevance, understanding, and interpretability through cognitive debriefing interviews (CDIs) with 21 US children. Face validity/translatability assessments were also performed. RESULTS: Key measurement concepts included cough, wheeze, difficulty breathing, chest tightness/discomfort, nighttime awakening, and daytime activity limitations. Concept saturation was reached during CEIs for primary asthma-related daytime and nighttime symptoms and core impacts. Most CDI participants found the ePASD items clear, understandable, and comprehensive. Standardized training is anticipated to facilitate reliable child self-report. CONCLUSION: The ePASD, a novel PROM for children aged 6-11 years with asthma, uses an innovative multimedia approach and has been developed in accordance with FDA PRO guidance and ISPOR good research practices, directly capturing the child's self-reported asthma symptoms, impacts on daily activities and nighttime awakening, and rescue medication use.

Effectiveness of fevipiprant in reducing exacerbations in patients with severe asthma (LUSTER-1 and LUSTER-2): two phase 3 randomised controlled trials.

BACKGROUND: Fevipiprant, an oral antagonist of the prostaglandin D2 receptor 2, reduced sputum eosinophils and improved lung function in phase 2 trials of patients with asthma. We aimed to investigate whether fevipiprant reduces asthma exacerbations in patients with severe asthma. METHODS: LUSTER-1 and LUSTER-2 were two phase 3 randomised, double-blind, placebo-controlled, parallel-group, replicate 52-week studies; LUSTER-1 took place at 174 clinical sites in 25 countries and LUSTER 2 took place at 169 clinical sites in 19 countries. Fevipiprant or placebo was added to Global Initiative for Asthma Steps 4 and 5 therapy in adolescents and adults with severe asthma. Patients aged 12 years or older with uncontrolled asthma on dual or triple asthma therapy were randomly assigned by use of interactive response technology to one of three treatment groups (once-daily fevipiprant 150 mg, fevipiprant 450 mg, or placebo) in a 1:1:1 ratio within each of the randomisation strata: peripheral blood eosinophil counts (<250 cells per µL or ≥250 cells per µL), patient age (<18 years or ≥18 years), and use or non-use of oral corticosteroids as part of their standard of care asthma therapy. The primary efficacy endpoint was the annualised rate of moderate to severe asthma exacerbations with 150 mg or 450 mg doses of fevipiprant once daily compared with placebo over 52 weeks, in patients with high blood eosinophil counts (≥250 cells per µL) and in the overall study population. All patients who underwent randomisation and received at least one dose of study medication were included in efficacy and safety analyses. These trials are registered with ClinicalTrials.gov, NCT02555683 (LUSTER-1) and NCT02563067 (LUSTER-2), and are complete and no longer recruiting. FINDINGS: Between Dec 11, 2015, and Oct 25, 2018, 894 patients were randomly assigned to fevipiprant 150 mg (n=301), fevipiprant 450 mg (n=295), or placebo (n=298) in LUSTER-1. Between Dec 3, 2015, and July 10, 2018, 877 patients were randomly assigned to fevipiprant 150 mg (n=296), fevipiprant 450 mg (n=294), or placebo (n=287) in LUSTER-2. In the high eosinophil population, in LUSTER-1 the annualised rate ratio of moderate to severe exacerbations compared with placebo was 1·04 (95% CI 0·77-1·41) for fevipiprant 150 mg and 0·83 (0·61-1·14) for fevipiprant 450 mg, and in LUSTER-2 it was 0·69 (0·50-0·96) for fevipiprant 150 mg and 0·72 (0·52-1·01) for fevipiprant 450 mg. In the overall population, in LUSTER-1 the annualised rate ratio of moderate to severe exacerbations compared with placebo was 0·96 (95% CI 0·75-1·22) for fevipiprant 150 mg and 0·78 (0·61-1·01) for fevipiprant 450 mg and in LUSTER-2 it was 0·82 (0·62-1·07) for fevipiprant 150 mg and 0·76 (0·58-1·00) for fevipiprant 450 mg. In the overall pooled population of both studies, serious adverse events occurred in 53 (9%) patients in the fevipiprant 150 mg group, 50 (9%) in the fevipiprant 450 mg group, and 50 (9%) in the placebo group. Adverse events leading to death occurred in two (<1%) patients in the fevipiprant 450 mg group and three (<1%) in the placebo group. INTERPRETATION: Although neither trial showed a statistically significant reduction in asthma exacerbations after adjusting for multiple testing, consistent and modest reductions in exacerbations rates were observed in both studies with the 450 mg dose of fevipiprant. FUNDING: Novartis.

Blood Eosinophils as Biomarkers to Drive Treatment Choices in Asthma and COPD.

BACKGROUND: Asthma and COPD are complex, heterogeneous conditions comprising a wide range of phenotypes, some of which are refractory to currently available treatments. Elucidation of these phenotypes and identification of biomarkers with which to recognize them and guide appropriate treatment remain a priority. OBJECTIVE: This review describes the utility of blood eosinophils as a surrogate biomarker of eosinophilic airway inflammation, a common feature of specific asthma and COPD phenotypes. The role of blood eosinophils in airway disease is described, as is their relevance in reflecting airway eosinophilia. Each disease is discussed separately as the manner in which blood eosinophils might be used as biomarkers differs. Focusing on patients with severe disease (persistent eosinophilic asthma and exacerbating COPD), we evaluate evidence examining eosinophils as biomarkers. RESULTS: In asthma, the rationale for using blood eosinophils to guide treatment is clearly defined, backed by prospective, well-controlled studies. Higher eosinophil counts identify patients with more severe disease and poorer outcomes, patients for whom biologic therapies targeting allergic and/or eosinophilic pathways are recommended. In COPD, the evidence is less robust. High blood eosinophil counts are a modest predictor of future exacerbations, and may predict a favourable response to ICS on top of LABA/LAMA, especially in patients with a history of frequent exacerbations. CONCLUSION: Before extensive application in clinical practice, further evaluation of these findings in prospective clinical studies, and standardization of the appropriate thresholds of clinically relevant eosinophilia are needed, together with establishing whether single or multiple measurements are required in different clinical settings.

Effects of beclomethason/formoterol and budesonide/formoterol fixed combinations on lung function and airway inflammation in patients with mild to moderate asthma--an exploratory study.

RATIONALE: Asthma is a chronic inflammatory airway disease of the whole bronchial tree. In this exploratory study we investigated the effects of beclomethasone/formoterol (becl/form) and budesonide/formoterol (bud/form) fixed combinations on lung function and airway inflammation in patients with mild to moderate asthma. METHODS: 22 adult patients with asthma (mean FEV1 91.6% pred.) were recruited to this prospective phase IV, double-blind, double-dummy, two-way cross-over, single-centre, randomised study. After a 7 days run-in period with bud 200 µg bid patients were randomised to receive 4 weeks of becl/form (100/6 µg) bid in a pressurised metered dose inhaler or bud/form (160/4.5 µg) bid administered via dry powder inhaler. We measured spirometry, bodyplethysmography, impulse oscillometry, nitric oxide (NO) and its alveolar fraction (CAlv), and assessed sputum cellularity. RESULTS: CAlv significantly decreased after 4 weeks of treatment in each treatment period. The adjusted geometric mean (log transformed data, end of treatment vs. baseline) was 0.942 ppb (95% CI: 0.778-1.141 ppb) for becl/form and 0.903 ppb (95% CI: 0.741-1.099 ppb) for bud/form. Impulse oscillometry revealed a significant decrease in mean Delta R5-R20 of -0.033 kPa * L(-1) * sec(-1) for becl/form (95% CI: -0.064 to -0.002) and of -0.048 033 kPa * L(-1) * sec(-1) for bud/form (95% CI: -0.079 to -0.017). Other parameters of lung function and NO showed numerically small and in most cases statistically non-significant changes. CONCLUSIONS: In patients with mild to moderate asthma pre-treated with inhaled corticosteroids, the use of ICS/LABA formulations led to improvements of CAlv and Delta R5-R20 indicating that these parameters might be helpful to further assess the effects of inhaled ICS/LABA combinations on lung function and airway inflammation.

Stepping-across controlled asthmatic patients to extrafine beclometasone/formoterol combination.

BACKGROUND: Asthma management focuses on achieving and maintaining asthma control. Few studies have assessed whether complete and sustained asthma control is maintained in clinical practice after stepping-across ICS/LABA fixed combinations. Aim of this double-blind, double-dummy, randomized, parallel group, controlled study was to demonstrate clinical equivalence between equipotent doses of extrafine beclometasone/formoterol (BDP/F) pMDI and fluticasone/salmeterol (FP/S) Diskus® in maintaining lung function and asthma control. METHODS: A total of 416 asthmatic patients already controlled with FP/S 500/100 µg/day (Diskus®, pMDI or separate inhalers) were randomized to a 12-week treatment with extrafine BDP/F 400/24 µg/day pMDI or FP/S 500/100 µg/day Diskus®. Pre-dose 1-s forced expiratory volume (FEV(1)) was the primary efficacy variable; secondary variables included asthma control questionnaire (ACQ-7) and FEV(1)0-1 h area under the curve (FEV(1)AUC(0-1h)). Safety was assessed through adverse events monitoring and vital signs. RESULTS: After 12 weeks of treatment, pre-dose FEV(1) did not differ between treatments (difference between means 0.01 L; 95% CI -0.03-0.06 L) with no significant changes from baseline in both groups (p = 0.726 and p = 0.783 in BDF/F arm and FP/S, respectively). ACQ-7 score showed that control was maintained after stepping-across to extrafine BDP/F. FEV(1)AUC(0-1h) was significantly higher in BDP/F arm at the beginning (p = 0.004) and at the end of the 12-week treatment period (p = 0.019). No safety issues were reported in both groups. CONCLUSIONS: Patients previously controlled with FP/S in any device formulation can effectively step-across to extrafine BDP/F pMDI, maintaining lung function and asthma control with a 5-min onset of action.

Rapid effects of extrafine beclomethasone dipropionate/formoterol fixed combination inhaler on airway inflammation and bronchoconstriction in asthma: a randomised controlled trial.

BACKGROUND: The dose-dependent anti-inflammatory effects of a recent fixed combination of extrafine beclomethasone dipropionate/formoterol (BDP/F) were investigated using non-invasive markers of inflammation, exhaled nitric oxide (NO) and adenosine monophosphate (AMP) provocative challenge. The aim was to assess the onset of the anti-inflammatory action of low and high doses and evaluate the suitability of non-invasive assessments to demonstrate dose response. METHODS: Steroid naïve adult out-patients with mild asthma, sensitive to AMP with baseline exhaled NO > 25 parts per billion entered a double-blind, placebo-controlled, 3-way, cross-over study. Patients were randomised to low dose (1 actuation) or high dose (4 actuations) extrafine BDP/F 100/6 µg, or placebo administered twice daily on Days 1 and 2 and once in the morning on Day 3 of each period. Exhaled NO was measured pre-dose on Day 1, then 2 and 4 hours post-administration on Day 3. The AMP challenge was performed 4 hours post-administration on Day 3 and forced expiratory volume in 1 second (FEV1, L) was measured from 0 to 4 hours post-dose on Day 1. Endpoints were NO at 2 and 4 hours, AMP challenge at 4 hours after the fifth dose on Day 3 and FEV1 area under the curve from 0 to 4 h post-dose on Day 1. Analysis of covariance was performed for NO and FEV1 and analysis of variance for AMP challenge. RESULTS: Eighteen patients were randomised and completed the study. Exhaled NO was significantly lower for both doses of extrafine BDP/F versus placebo at 2 and 4 hours (high dose LS mean difference: -22.5 ppb, p < 0.0001 and -20.5 ppb, p < 0.0001; low dose: -14.1 ppb, p = 0.0006 and -12.1 ppb, p = 0.0043) with a significant dose response (p = 0.0342 and p = 0.0423). Likewise, AMP challenge revealed statistically significant differences between both doses of extrafine BDP/F and placebo (high dose LS mean difference: 4.8 mg/mL, p < 0.0001; low dose: 3.7 mg/mL, p < 0.0001), and a significant dose response (p = 0.0185). FEV1 was significantly improved versus placebo for both doses (high dose LS mean difference: 0.2 L, p = 0.0001; low dose: 0.2 L p = 0.0001), but without a significant dose response. CONCLUSIONS: The fixed combination inhaler of extrafine BDP/F has early dose-dependent anti-inflammatory effects with a rapid onset of bronchodilatation in mild asthmatic patients. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01343745.

Nitric oxide synthase isoenzyme expression and activity in peripheral lung tissue of patients with chronic obstructive pulmonary disease.

RATIONALE: Nitric oxide (NO) is increased in the lung periphery of patients with chronic obstructive pulmonary disease (COPD). However, expression of the NO synthase(s) responsible for elevated NO has not been identified in the peripheral lung tissue of patients with COPD of varying severity. METHODS: Protein and mRNA expression of nitric oxide synthase type I (neuronal NOS [nNOS]), type II (inducible NOS [iNOS]), and type III (endothelial NOS [eNOS]) were quantified by Western blotting and reverse transcription-polymerase chain reaction, respectively, in specimens of surgically resected lung tissue from nonsmoker control subjects, patients with COPD of varying severity, and smokers without COPD, and in a lung epithelial cell line (A549). The effects of nitrative/oxidative stress on NOS expression and activity were also evaluated in vitro in A549 cells. nNOS nitration was quantified by immunoprecipitation and dimerization of nNOS was detected by low-temperature SDS-PAGE/Western blot in the presence of the peroxynitrite generator, 3-morpholinosydnonimine-N-ethylcarbamide (SIN1), in vitro and in vivo. MEASUREMENTS AND MAIN RESULTS: Lung tissue from patients with severe and very severe COPD had graded increases in nNOS (mRNA and protein) compared with nonsmokers and normal smokers. Hydrogen peroxide (H(2)O(2)) and SIN1 as well as the cytokine mixture (IFN-gamma, IL-1beta, and tumor necrosis factor-alpha) increased mRNA expression and activity of nNOS in A549 cells in a concentration-dependent manner compared with nontreated cells. Tyrosine nitration resulted in an increase in nNOS activity in vitro, but did not affect its dimerization. CONCLUSIONS: Patients with COPD have a significant increase in nNOS expression and activity that reflects the severity of the disease and may be secondary to oxidative stress.

Peroxynitrite elevation in exhaled breath condensate of COPD and its inhibition by fudosteine.

BACKGROUND: Peroxynitrite (PN) formed by the reaction of nitric oxide and superoxide is a powerful oxidant/nitrosant. Nitrative stress is implicated in COPD pathogenesis, but PN has not been detected due to a short half-life (< 1 s) at physiologic condition. Instead, 3-nitrotyrosine has been measured as a footprint of PN release. METHOD: PN was measured using oxidation of 2',7'-dichlorofluorescein (DCDHF) in exhaled breath condensate (EBC) collected in high pH and sputum cells. The PN scavenging effect was also evaluated by the same system as PN-induced bovine serum albumin (BSA) nitration. RESULTS: The mean (+/- SD) PN levels in EBC of COPD patients (7.9 +/- 3.0 nmol/L; n = 10) were significantly higher than those of healthy volunteers (2.0 +/- 1.1 nmol/L; p < 0.0001; n = 8) and smokers (2.8 +/- 0.9 nmol/L; p = 0.0017; n = 6). There was a good correlation between PN level and disease severity (FEV(1)) in COPD (p = 0.0016). Fudosteine (FDS), a unique mucolytic antioxidant, showed a stronger scavenging effect of PN than N-acetyl-cysteine on DCDHF oxidation in vitro and in sputum macrophages, and also on PN-induced BSA nitration. FDS (0.1 mmol/L) reduced PN-enhanced interleukin (IL)-1beta-induced IL-8 release and restored corticosteroid sensitivity defected by PN more potently than those induced by H(2)O(2) in A549 airway epithelial cells. CONCLUSION: This noninvasive PN measurement in EBC may be useful for monitoring airway nitrative stress in COPD. Furthermore, FDS has the potential to inhibit PN-induced events in lung by its scavenging effect.

Effects of aminoguanidine, an inhibitor of inducible nitric oxide synthase, on nitric oxide production and its metabolites in healthy control subjects, healthy smokers, and COPD patients.

BACKGROUND: Nitric oxide (NO) is produced by resident and inflammatory cells in the respiratory tract by the enzyme NO synthase (NOS), which exists in three isoforms: neuronal NOS (nNOS), inducible NOS (iNOS), and endothelial NOS. NO production is increased in patients with COPD, and the production of NO under oxidative stress conditions generates reactive nitrogen species that may amplify the inflammatory response in COPD. METHODS: To examine the role of increased NO in COPD, we administered a relatively selective iNOS inhibitor, aminoguanidine, by nebulization in a double-blind, placebo-controlled study in COPD patients, healthy smokers, and healthy nonsmoking subjects. We investigated whether aminoguanidine had any effect on exhaled NO produced in the central lung (flux of NO from the airways [Jno] and peripheral lungs (concentration of NO in peripheral lung [Calv], on NO metabolites (nitrite [NO(2)(-)]/nitrate [NO(3)(-)], peroxinitrite [ONOO(-)], nitrotyrosine), and on a marker of oxidative stress (8-isoprostane) in exhaled breath condensate (EBC) and in sputum. RESULTS: Aminoguanidine administration resulted in a significant reduction in Jno compared with administration of the saline solution control in healthy subjects, smokers, and COPD patients. Calv in smokers and in COPD patients was not completely inhibited 1 h after aminoguanidine inhalation, in marked contrast to previous results in asthma. Moreover, ONOO(-) and NO(2)(-)/NO(3)(-) levels were also increased in EBC and in sputum of smokers and COPD and were not completely inhibited following aminoguanidine inhalation. 8-Isoprostane levels were also increased in smokers and in COPD patients but were not reduced after aminoguanidine inhalation. CONCLUSIONS: These results suggest that the constitutive NOS isoform as well as iNOS might be involved in NO release and contribute to the high Calv and ONOO(-) production in patients with COPD. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT00180635.

Effect of an inducible nitric oxide synthase inhibitor on differential flow-exhaled nitric oxide in asthmatic patients and healthy volunteers.

Nitric oxide (NO) is produced by a variety of cells within the respiratory tract, particularly airway epithelial cells, and its increased concentration in asthma is likely to derive from inducible NO synthase (iNOS) expressed in inflamed airways. To evaluate whether an increased bronchial flux of NO (ie, airway wall NO flux [Jno] in picoliters per second) produced in the large airways is due to an enzyme overexpression, we administered a relatively selective iNOS inhibitor, aminoguanidine, by nebulization in a double-blind, placebo-controlled manner in asthmatic and healthy subjects and also investigated whether the same concentration of inhibitor has any effect on NO produced in the peripheral lungs (ie, alveolar NO concentration [Calv] in parts per billion [ppb]) or on the diffusing capacity of NO (Dno) [in picoliters per second(-1) per ppb(-1)) in the airways. Aminoguanidine administration resulted in a significant reduction in Jno compared with administration of the saline solution control in eight healthy subjects and in eight patients with asthma but caused no significant changes in Calv or in Dno in either group. No rise in BP, fall in FEV(1), or adverse effects were observed in either group. These results indicate that iNOS from larger airways is the predominant source of elevated large airway-derived NO in patients with asthma, and that exhaled NO from peripheral lungs is not affected by a nebulized iNOS inhibitor and, therefore, is more likely to be derived form constitutive forms of NO synthase.

Differential flow analysis of exhaled nitric oxide in patients with asthma of differing severity.

BACKGROUND: The majority of asthmatic patients achieve control of their illness; others do not. It is therefore crucial to validate/develop strategies that help the clinician monitor the disease, improving the response to treatment. METHODS: We have quantified the inflammation in central and peripheral airways by measuring exhaled nitric oxide (NO) at multiple exhalation flows in 56 asthmatics at different levels of severity (mild, n = 10; moderate stable, n = 17; moderate during exacerbation, n = 11; severe, n = 18, 7 of whom were receiving oral corticosteroids) and 18 healthy control subjects. The reproducibility of the measurement was also assessed. RESULTS: Bronchial NO (Jno) in patients with mild asthma (2,363 +/- 330 pL/s) [mean +/- SD] was higher than in patients with moderate stable asthma (1,300 +/- 59 pL/s, p < 0.0005), in patients with severe asthma receiving inhaled corticosteroids (ICS) [1,015 +/- 67 pL/s, p < 0.0005], and healthy control subjects (721 +/- 22 pL/s, p < 0.0001). There were no differences between Jno in patients with mild asthma compared to patients with severe asthma receiving ICS and oral corticosteroids (2,225 +/- 246 pL/s). Patients with exacerbations showed a higher Jno (3,475 +/- 368.9 pL/s, p < 0.05) compared to the other groups. Alveolar NO was higher in patients with severe asthma receiving oral corticosteroids (3.0 +/- 0.1 parts per billion [ppb], p < 0.0001) than in the other groups but was not significantly higher than in patients with moderate asthma during exacerbation (2.8 +/- 0.3 ppb). No differences were seen in NO diffusion levels between the different asthma groups. All the measurements were highly reproducible and free of day-to-day and diurnal variations. CONCLUSIONS: Differential flow analysis of exhaled NO provides additional information about the site of inflammation in asthma and may be useful in assessing the response of peripheral inflammation to therapy.

Measurement of bronchial and alveolar nitric oxide production in normal children and children with asthma.

RATIONALE: Airway inflammation is characteristic of asthma. Distal inflammation may be particularly important. OBJECTIVE: To calculate alveolar nitric oxide (NO) concentration (C(alv)) and bronchial flux NO (J(NO)) in children. METHODS: We measured C(alv) and J(NO) from the fractional exhaled NO (FeNO(50)) measured at multiple exhalation flow rates in 132 children (aged 4-18 yr) with known atopic status, medication, and asthma control. MEASUREMENTS AND MAIN RESULTS: Of participants, 85% (112/132) completed all measurements. In 20 of 112, the result did not fit the linear model. Thus, J(NO) and C(alv) were assessed in 92 (70%) subjects. The median (range) values of asthmatic (n = 52), normal (n = 20), and nonasthmatic atopic (n = 20) children were as follows: FeNO(50): 28.1 (4.3-190), 10.35 (3.3-29), 21.8 (8.7-69) ppb, respectively; J(NO): 1,230 (204-9,236), 480 (196-1,913), 1,225 (486-4,119) pl/s, respectively; C(alv): 2.22 (0.44-6.63), 1.63 (0.44-3), 1.21 (0.03-2.85) ppb, respectively. A reproducibility study in 18 other children gave intraclass correlation coefficients (single measures) of 0.99 (J(NO)) and 0.81 (C(alv)). J(NO) and C(alv) were higher in children with asthma than normal children (p = 0.0004 and p = 0.0002, respectively). Children with poorly controlled asthma (n = 27) had higher FeNO(50) measurements than children with good symptom control (n = 25): C(alv): mean (+/- SD), 3.17 +/- 1.62 versus 2.26 +/- 1.30 ppb, p = 0.03; J(NO): mean (+/- SD), 2,634 +/- 2,255 versus 1,193 +/- 1,294 pl/s, p = 0.007, respectively. CONCLUSIONS: Measurement of J(NO) and C(alv) is feasible in 70% of school-age children. FeNO(50) and J(NO) give the same information (r = 0.97, p < 0.0001), C(alv) is higher in asthmatic children than in normal children and is affected by asthma control, but not by atopy. C(alv) may possibly reflect alveolar inflammation in asthma.

Effects of aerosolized adenosine 5'-triphosphate vs adenosine 5'-monophosphate on dyspnea and airway caliber in healthy nonsmokers and patients with asthma.

STUDY OBJECTIVES: Extracellular adenosine 5'-triphosphate (ATP) causes neurogenic bronchoconstriction, inflammation, and coughs, and may play a mechanistic role in obstructive airway diseases. The aims of this study were to determine the effects of inhaled ATP on airway function, and to compare these effects with those of adenosine 5'-monophosphate (AMP). DESIGN: Prospective, randomized, double-blind study. SETTING: Clinical research laboratory of a postgraduate teaching hospital. METHODS: The effects of inhaled equimolar doses of ATP and AMP on airway caliber, perception of dyspnea quantified by the Borg score, and other symptoms were determined in 10 nonsmokers (age 41 +/- 3 years) and 10 patients with asthma (age 39 +/- 3 years) [+/- SEM]. RESULTS: None of the healthy nonsmokers responded to ATP or AMP. All the patients with asthma responded to ATP, and 90% responded to AMP. The geometric mean of the provocative dose causing a 20% fall in FEV1 (PD20) of ATP was 48.7 micromol/mL and that of PD20 AMP was 113.5 micromol/mL in responsive asthmatics (p < 0.05). In asthmatic patients, the percentage change in FEV1 caused by ATP was greater than that caused by AMP (deltaFEV1 ATP = 29% vs deltaFEV1 AMP = 22%, p < 0.05). Borg score increased significantly in asthmatics after ATP (from 0.1 to 3.3, p < 0.01) and after AMP (from 0.2 to 2.5, p < 0.01). This increase was also greater after ATP than AMP in asthma (deltaBorg ATP = 3.2 vs deltaBorg AMP = 2.3, p < 0.05). ATP induced cough in 16 subjects (80%), while AMP induced cough in 8 subjects (40%) [p < 0.05]; in addition, more subjects had throat irritation after inhalation of ATP than AMP (p < 0.05). CONCLUSIONS: ATP is a more potent bronchoconstrictor and has greater effects on dyspnea and other symptoms than AMP in asthmatic patients. Therefore, ATP could potentially be used as a bronchoprovocator in the clinical setting.

Hypercapnia in overlap syndrome: possible determinant factors.

We retrospectively evaluated data from 213 consecutive patients; 152 were affected by obstructive sleep apnea (OSA), 29 had OSA associated with chronic obstructive pulmonary disease (COPD), also known as overlap syndrome, and 32 had COPD. Patients with obesity-hypoventilation syndrome were not included. The aims of the study were to evaluate the anthropometric, pulmonary, and polysomnographic characteristics of patients affected by overlap syndrome compared to "simple" OSA and to COPD subjects and to analyze the determinants of hypercapnia in overlap syndrome. In the comparison between overlap and OSA patients, the overlap group had a significantly higher PaCO2 (44.59 vs. 39.22 mm Hg; p < 0.01), in the presence of a similar AHI (40.46 vs. 41.59/h). Comparing overlap to COPD patients, overlap showed a significantly higher PaCO2 value (44.59 vs. 39.63 mm Hg; p < 0.005) and had significantly less severe obstructive impairment (FEV 162.93 vs. 47.31%; FEV1/FVC ratio 66.71 vs. 59.25%; p < 0.005). Anthropometric, pulmonary function, and polysomnographic data did not differ between normo- and hypercapnic overlap patients. The best model (stepwise multiple regression analysis) for predicting PaCO2 in overlap patients showed r2 value 0.65: PaO2 contributed to 38%, FEV1 to 15%, and weight to 12%. In conclusion, the occurrence of hypercapnia in overlap patients is only partially explained by the combination of overweight and reduced respiratory function, supporting the hypothesis of a multifactorial genesis.