Lack of long-term effects of high-dose inhaled beclomethasone for respiratory syncytial virus bronchiolitis: a randomized placebo-controlled trial

UPDATE - 2022 Italian guidelines on the management of bronchiolitis in infants

Bronchiolitis is an acute respiratory illness that is the leading cause of hospitalization in young children. This document aims to update the consensus document published in 2014 to provide guidance on the current best practices for managing bronchiolitis in infants. The document addresses care in both hospitals and primary care. The diagnosis of bronchiolitis is based on the clinical history and physical examination. The mainstays of management are largely supportive, consisting of fluid management and respiratory support. Evidence suggests no benefit with the use of salbutamol, glucocorticosteroids and antibiotics with potential risk of harm. Because of the lack of effective treatment, the reduction of morbidity must rely on preventive measures. De-implementation of non-evidence-based interventions is a major goal, and educational interventions for clinicians should be carried out to promote high-value care of infants with bronchiolitis. Well-prepared implementation strategies to standardize care and improve the quality of care are needed to promote adherence to guidelines and discourage non-evidence-based attitudes. In parallel, parents' education will help reduce patient pressure and contribute to inappropriate prescriptions. Infants with pre-existing risk factors (i.e., prematurity, bronchopulmonary dysplasia, congenital heart diseases, immunodeficiency, neuromuscular diseases, cystic fibrosis, Down syndrome) present a significant risk of severe bronchiolitis and should be carefully assessed. This revised document, based on international and national scientific evidence, reinforces the current recommendations and integrates the recent advances for optimal care and prevention of acute bronchiolitis.

Prevention and Treatment Strategies for Respiratory Syncytial Virus (RSV)

Respiratory syncytial virus (RSV) is a leading cause of severe lower respiratory tract disease, especially in young children. Despite its global impact on healthcare, related to its high prevalence and its association with significant morbidity, the current therapy is still mostly supportive. Moreover, while more than 50 years have passed since the first trial of an RSV vaccine (which unfortunately caused enhanced RSV disease), no vaccine has been approved for RSV prevention. In the last two decades, our understanding of the pathogenesis and immunopathology of RSV have continued to evolve, leading to significant advancements in RSV prevention strategies. These include both the development of new potential vaccines and the successful implementation of passive immunization, which, together, will provide coverage from infancy to old age. In this review, we provide an update of the current treatment options for acute disease (RSV-specific and -non-specific) and different therapeutic approaches focusing on RSV prevention.

Azithromycin to Prevent Recurrent Wheeze Following Severe Respiratory Syncytial Virus Bronchiolitis

BACKGROUND

Early-life severe respiratory syncytial virus (RSV) bronchiolitis is a risk factor for childhood asthma. Because azithromycin may attenuate airway inflammation during RSV bronchiolitis, we evaluated whether it would reduce the occurrence of post-RSV recurrent wheeze.

METHODS

We prospectively enrolled 200 otherwise healthy 1- to 18-month-old children hospitalized with RSV bronchiolitis in this single-center, double-blind, placebo-controlled study and randomly assigned them to receive oral azithromycin (10 mg/kg daily for 7 days, followed by 5 mg/kg daily for 7 days) or placebo. Randomization was stratified by recent open-label antibiotic use. The primary outcome was the occurrence of recurrent wheeze, defined as a third episode of post-RSV wheeze over the following 2 to 4 years.

RESULTS

As an indication of the biologic activity of azithromycin, nasal wash interleukin-8 levels, at day 14 after randomization, were lower among azithromycin-treated participants (P<0.01). Despite evidence of biologic activity, azithromycin did not reduce the risk of post-RSV recurrent wheeze (47% in the azithromycin group vs. 36% in the placebo group; adjusted hazard ratio, 1.45; 95% confidence interval [CI], 0.92 to 2.29; P=0.11). Azithromycin also did not modify the risk of recurrent wheeze among participants already receiving other antibiotic treatment at the time of enrollment (hazard ratio, 0.94; 95% CI, 0.43 to 2.07). There was a potential signal among antibiotic-naïve participants who received azithromycin to have an increased risk of recurrent wheeze (hazard ratio, 1.79; 95% CI, 1.03 to 3.1).

CONCLUSIONS

Azithromycin therapy for 14 days during acute severe RSV bronchiolitis did not reduce recurrent wheeze occurrence over the following 2 to 4 years. Our data suggest no benefit of azithromycin administration with the goal of preventing recurrent wheeze in later life. (Funded by the National Heart, Lung, and Blood Institute; ClinicalTrials.gov number, NCT02911935.).

The azithromycin to prevent wheezing following severe RSV bronchiolitis-II clinical trial: Rationale, study design, methods, and characteristics of study population

Severe respiratory syncytial virus (RSV) bronchiolitis in early life is a significant risk factor for future recurrent wheeze (RW) and asthma. The goal of the Azithromycin to Prevent Wheezing following severe RSV bronchiolitis II (APW-RSV II) clinical trial is to evaluate if azithromycin treatment in infants hospitalized with RSV bronchiolitis reduces the occurrence of RW during the preschool years. The APW-RSV II clinical trial is a double-blind, placebo-controlled, parallel-group, randomized trial, including otherwise healthy participants, ages 30 days-18 months, who are hospitalized due to RSV bronchiolitis. The study includes an active randomized treatment phase with azithromycin or placebo for 2 weeks, and an observational phase of 18-48 months. Two hundred participants were enrolled during three consecutive RSV seasons beginning in the fall of 2016 and were randomized to receive oral azithromycin 10 mg/kg/day for 7 days followed by 5 mg/kg/day for an additional 7 days, or matched placebo. The study hypothesis is that in infants hospitalized with RSV bronchiolitis, the addition of azithromycin therapy to routine bronchiolitis care would reduce the likelihood of developing post-RSV recurrent wheeze (≥3 episodes). The primary clinical outcome is the occurrence of a third episode of wheezing, which is evaluated every other month by phone questionnaires and during yearly in-person visits. A secondary objective of the APW-RSV II clinical trial is to examine how azithromycin therapy changes the upper airway microbiome composition, and to determine if these changes are related to the occurrence of post-RSV RW. Microbiome composition is characterized in nasal wash samples obtained before and after the study treatments. This clinical trial may identify the first effective intervention applied during severe RSV bronchiolitis to reduce the risk of post-RSV RW and ultimately asthma.

Respiratory Syncytial Virus-Associated Hospital Admissions in Children Younger Than 5 Years in 7 European Countries Using Routinely Collected Datasets

BACKGROUND

Respiratory syncytial virus (RSV) is a leading cause of respiratory tract infection (RTI) in young children. Registries provide opportunities to explore RSV epidemiology and burden.

METHODS

We explored routinely collected hospital data on RSV in children aged < 5 years in 7 European countries. We compare RSV-associated admission rates, age, seasonality, and time trends between countries.

RESULTS

We found similar age distributions of RSV-associated hospital admissions in each country, with the highest burden in children < 1 years old and peak at age 1 month. Average annual rates of RTI admission were 41.3-112.0 per 1000 children aged < 1 year and 8.6-22.3 per 1000 children aged < 1 year. In children aged < 5 years, 57%-72% of RTI admissions with specified causal pathogen were coded as RSV, with 62%-87% of pathogen-coded admissions in children < 1 year coded as RSV.

CONCLUSIONS

Our results demonstrate the benefits and limitations of using linked routinely collected data to explore epidemiology and burden of RSV. Our future work will use these data to generate estimates of RSV burden using time-series modelling methodology, to inform policymaking and regulatory decisions regarding RSV immunization strategy and monitor the impact of future vaccines.

LL-37 restored glucocorticoid sensitivity impaired by virus dsRNA in lung

Glucocorticoids play a key role in treatment of inflammatory lung diseases including both airway and parenchymal lung diseases. RNA viral infections are major causes of chronic lung disease exacerbations and can determine glucocorticoid resistance. The antibacterial peptide LL-37, the only member of human cathelicidin family, also functions as antiviral-activity enhancer. However, whether it can alleviate the glucocorticoid resistance caused by RNA viruses remains unclear. Here, we used type I (BEAS-2B) and type II (A549) lung epithelial cells to assess the effect of LL-37 on dsRNA-induced glucocorticoid resistance. We verified that LL-37 and polyinosinic-polycytidylic acid (poly I:C, a mimic of viral dsRNA) interact and enter both cell lines. Co-treatment with LL-37 and poly I:C increased glucocorticoid-induced expression of promyelocytic leukemia zinc finger (PLZF), an anti-inflammatory protein, compared to poly I:C alone. Pre-treatment with LL-37 also restored transactivation of the glucocorticoid response element (GRE). Moreover, LL-37 rescued poly I:C-induced glucocorticoid resistance by increasing phosphorylation and nuclear translocation of glucocorticoid receptor. Importantly, LL-37 downregulated poly I:C-induced Erk and Akt signaling pathways in lung epithelial cells. Finally, we verified our data in vivo, showing that mCRAMP, the mouse LL-37 ortholog, can alleviate poly I:C-induced glucocorticoid insensitivity in a murine asthma model. In summary, this study showed that LL-37 restored glucocorticoid sensitivity impaired by dsRNA possibly by inhibiting Akt pathway, in addition to Erk1/2 pathway. These findings suggest LL-37 as a therapeutic agent for treatment of viral infections in inflammatory pulmonary diseases.

Identification of IFN-γ and IL-27 as Critical Regulators of Respiratory Syncytial Virus-Induced Exacerbation of Allergic Airways Disease in a Mouse Model

Respiratory syncytial virus (RSV) infection induces asthma exacerbations, which leads to worsening of clinical symptoms and may result in a sustained decline in lung function. Exacerbations are the main cause of morbidity and mortality associated with asthma, and significantly contribute to asthma-associated healthcare costs. Although glucocorticoids are used to manage exacerbations, some patients respond to them poorly. The underlying mechanisms associated with steroid-resistant exacerbations remain largely unknown. We have previously established a mouse model of RSV-induced exacerbation of allergic airways disease, which mimics hallmark clinical features of asthma. In this study, we have identified key roles for macrophage IFN-γ and IL-27 in the regulation of RSV-induced exacerbation of allergic airways disease. Production of IFN-γ and IL-27 was steroid-resistant, and neutralization of IFN-γ or IL-27 significantly suppressed RSV-induced steroid-resistant airway hyperresponsiveness and airway inflammation. We have previously implicated activation of pulmonary macrophage by TNF-α and/or MCP-1 in the mechanisms of RSV-induced exacerbation. Stimulation of pulmonary macrophages with TNF-α and/or MCP-1 induced expression of both IFN-γ and IL-27. Our findings highlight critical roles for IFN-γ and IL-27, downstream of TNF-α and MCP-1, in the mechanism of RSV-induced exacerbation. Thus, targeting the pathways that these factors activate may be a potential therapeutic approach for virus-induced asthma exacerbations.

Glucocorticoid Insensitivity in Virally Infected Airway Epithelial Cells Is Dependent on Transforming Growth Factor-β Activity

Asthma and chronic obstructive pulmonary disease (COPD) exacerbations are commonly associated with respiratory syncytial virus (RSV), rhinovirus (RV) and influenza A virus (IAV) infection. The ensuing airway inflammation is resistant to the anti-inflammatory actions of glucocorticoids (GCs). Viral infection elicits transforming growth factor-β (TGF-β) activity, a growth factor we have previously shown to impair GC action in human airway epithelial cells through the activation of activin-like kinase 5 (ALK5), the type 1 receptor of TGF-β. In the current study, we examine the contribution of TGF-β activity to the GC-resistance caused by viral infection. We demonstrate that viral infection of human bronchial epithelial cells with RSV, RV or IAV impairs GC anti-inflammatory action. Poly(I:C), a synthetic analog of double-stranded RNA, also impairs GC activity. Both viral infection and poly(I:C) increase TGF-β expression and activity. Importantly, the GC impairment was attenuated by the selective ALK5 (TGFβRI) inhibitor, SB431542 and prevented by the therapeutic agent, tranilast, which reduced TGF-β activity associated with viral infection. This study shows for the first time that viral-induced glucocorticoid-insensitivity is partially mediated by activation of endogenous TGF-β.

In this study, we investigate how respiratory viral infection interferes with the anti-inflammatory actions of glucocorticoid (GC) drugs, which are a highly effective group of anti-inflammatory agents widely used in the treatment of chronic inflammatory airway diseases, including asthma and chronic obstructive pulmonary disease (COPD). Exacerbations of both asthma (“asthma attacks”) and COPD are often caused by viral infection, which does not respond well to GC therapy. Patients are often hospitalized placing a large burden on healthcare systems around the world, with the young, elderly, and those with a poor immune system particularly at risk. We show that viral infection of airway epithelial cells causes increased expression and activity of transforming growth factor-beta (TGF-β), which interferes with GC drug action. Importantly, we have shown for the first time that inhibiting TGF-β activity in the airways could serve as a new strategy to prevent and/or treat viral exacerbations of chronic airway diseases.

Predictors of asthma following severe respiratory syncytial virus (RSV) bronchiolitis in early childhood

BACKGROUND

We sought to identify predictors of asthma development following severe early childhood RSV bronchiolitis. Different definitions of asthma were also compared.

METHODS

This longitudinal, observational study (N = 343) followed patients (<2 years old) from a placebo-controlled trial (N = 979) of montelukast after RSV bronchiolitis to identify clinical, demographic, or biochemical predictors of asthma, atopic disorders, and chronic asthma therapy use at 6 years of age (Clinical Trials Registry Number: NCT01140048). Asthma (primary definition) was based on parental identification of wheeze at 6 AND 12 months before 6 years of age; definitions based on physician diagnosis as well as parental identification of wheeze at 6 OR 12 months (to consider seasonal effect) were also assessed. Post-hoc analyses evaluated agreement among asthma diagnosis criteria.

RESULTS

Prevalence of asthma (primary definition by parental identification), asthma (physician diagnosis), atopic disorders, and chronic asthma therapy use (parental identification) was 6.1%, 22.4%, 36.2%, and 14.5%, respectively. Predictors for asthma (primary definition) included male gender, a relative with asthma, and RAST positive for dog dander; for physician diagnosis of asthma, high severity score for RSV bronchiolitis, high respiratory rate, and asthma diagnosis before enrollment. Predictors of atopic disorders included allergic rhinitis before enrollment, a relative with asthma, and the plasma biomarkers IL-5, IL-16, and IL-18. Predictors of chronic asthma therapy use included asthma diagnosis before enrollment and geographic region (Europe and Africa). Only 42% of patients with asthma (primary definition) also met the asthma definition by physician diagnosis and chronic asthma therapy use.

CONCLUSION

Among children with early RSV bronchiolitis, hereditary factors (i.e., having a relative with asthma) and RSV bronchiolitis severity were predictors of asthma and atopic disorders at 6 years of age. Of interest, there was poor agreement among the asthma definitions evaluated. Pediatr Pulmonol. 2016;51:1382-1392. © 2016 Wiley Periodicals, Inc.

TNF-α and Macrophages Are Critical for Respiratory Syncytial Virus-Induced Exacerbations in a Mouse Model of Allergic Airways Disease

Viral respiratory infections trigger severe exacerbations of asthma, worsen disease symptoms, and impair lung function. To investigate the mechanisms underlying viral exacerbation, we established a mouse model of respiratory syncytial virus (RSV)-induced exacerbation after allergen sensitization and challenge. RSV infection of OVA-sensitized/challenged BALB/c mice resulted in significantly increased airway hyperresponsiveness (AHR) and macrophage and neutrophil lung infiltration. Exacerbation was accompanied by increased levels of inflammatory cytokines (including TNF-α, MCP-1, and keratinocyte-derived protein chemokine [KC]) compared with uninfected OVA-treated mice or OVA-treated mice exposed to UV-inactivated RSV. Dexamethasone treatment completely inhibited all features of allergic disease, including AHR and eosinophil infiltration, in uninfected OVA-sensitized/challenged mice. Conversely, dexamethasone treatment following RSV-induced exacerbation only partially suppressed AHR and failed to dampen macrophage and neutrophil infiltration or inflammatory cytokine production (TNF-α, MCP-1, and KC). This mimics clinical observations in patients with exacerbations, which is associated with increased neutrophils and often poorly responds to corticosteroid therapy. Interestingly, we also observed increased TNF-α levels in sputum samples from patients with neutrophilic asthma. Although RSV-induced exacerbation was resistant to steroid treatment, inhibition of TNF-α and MCP-1 function or depletion of macrophages suppressed features of disease, including AHR and macrophage and neutrophil infiltration. Our findings highlight critical roles for macrophages and inflammatory cytokines (including TNF-α and MCP-1) in viral-induced exacerbation of asthma and suggest examination of these pathways as novel therapeutic approaches for disease management.

Latest options for treatment of bronchiolitis in infants

Bronchiolitis is the most frequent pathology associated with lower respiratory tract infection in newborns and young infants. The treatment of bronchiolitis is essentially supportive therapy for respiratory distress, hypoxia and dehydration. To date, no specific antiviral drug is used on a routine basis for the treatment of RSV infections. Currently, the only antiviral drug approved for the infection is ribavirin; however, its use is limited due to adverse side effects and the risks it poses to healthcare providers. Moreover, several drugs have been routinely administered for years in infants with acute RSV bronchiolitis, even if their efficacy is often not confirmed by clinical evidence, and studies on emerging antiviral drugs are still ongoing. In the present paper we review the recent literature about the drugs used during acute bronchiolitis and we summarize the main recommendations of national and international guidelines and the latest options for the treatment of bronchiolitis.

Preschool Wheezing Phenotypes

Wheezing in preschool children is very common, with a wide differential diagnosis. It is essential to be sure of the exact sound that parents are describing; the term ‘wheeze‘ is often applied to non-specific sounds. Structural airway disease such as vascular ring should be considered. Thereafter we propose that umbrella terms for preschool wheeze should be abandoned in favour of ‘Hargreave phenotyping’, in which the presence and extent of the components of infection, inflammation, variable airflow obstruction, and fixed airflow obstruction are determined as far as is possible, rather than using a general umbrella term such as ‘asthma’. The justification for this approach is that it leads to a logical approach to treatment in the disparate airway diseases presenting in the preschool years, and should hopefully prevent over-treatment with inhaled corticosteroids. If, despite this approach, doubt remains as to the nature of the airway disease, then a therapeutic trial of treatment is permissible, but it should be for a short defined period only. In any event, such children should be reviewed regularly to see if treatments need to be changed.

The Effects of Inhaled Steroids on Recurrent Wheeze After Acute Bronchiolitis: A Systematic Review and Meta-Analysis of 748 Patients

Background. Acute bronchiolitis infection during infancy is associated with an increased risk of asthma later in life. The objective of this study was to determine if inhaled steroids are effective in preventing the development of recurrent wheeze or asthma following acute bronchiolitis. Methods. Multiple databases and bibliographies of selected references were searched. Inclusion required (a) a randomized controlled trial of inhaled steroids and control group, (b) at least 2 weeks duration of therapy started during the acute phase of disease, and (c) identification of the rate of recurrent wheeze or asthma at least 6 months after therapy. Results. Of 1410 studies reviewed, 8 reports were included in this meta-analysis (748 patients). The overall odds ratio for developing recurrent wheeze or asthma with treatment versus without treatment was 1.02 (95% confidence interval = 0.58-1.81). Conclusions. A course of inhaled steroids after acute bronchiolitis is not effective in preventing recurrent wheeze or asthma.

Randomized trial to evaluate azithromycin's effects on serum and upper airway IL-8 levels and recurrent wheezing in infants with respiratory syncytial virus bronchiolitis

BACKGROUND

Respiratory syncytial virus (RSV) bronchiolitis in infancy is a major risk factor for recurrent wheezing and asthma. Because azithromycin attenuated neutrophilic airway inflammation in a murine viral bronchiolitis model, demonstration of similar effects in human subjects might provide a strategy for the prevention of postbronchiolitis recurrent wheezing.

OBJECTIVES

We sought to investigate whether azithromycin treatment during RSV bronchiolitis reduces serum and nasal lavage IL-8 levels and the occurrence of postbronchiolitis recurrent wheezing.

METHOD

We performed a randomized, double-masked, placebo-controlled proof-of-concept trial in 40 otherwise healthy infants hospitalized with RSV bronchiolitis who were treated with azithromycin or placebo for 14 days. IL-8 levels were measured in nasal lavage fluid and serum on randomization, day 8, and day 15 (nasal lavage only). The occurrence of wheezing episodes was assessed monthly over the ensuing 50 weeks.

RESULTS

Compared with placebo, azithromycin treatment did not reduce serum IL-8 levels at day 8 (P = .6) but resulted in a greater decrease in nasal lavage fluid IL-8 levels by day 15 (P = .03). Twenty-two percent of azithromycin-treated participants experienced at least 3 wheezing episodes compared with 50% of participants in the placebo group (P = .07). Azithromycin treatment resulted in prolonged time to the third wheezing episode (P = .048) and in fewer days with respiratory symptoms over the subsequent year in comparison with placebo (36.7 vs 70.1 days, P = .01).

CONCLUSION

In this proof-of-concept study azithromycin treatment during RSV bronchiolitis reduced upper airway IL-8 levels, prolonged the time to the third wheezing episode, and reduced overall respiratory morbidity over the subsequent year.

Challenges and opportunities in developing respiratory syncytial virus therapeutics

Two meetings, one sponsored by the Wellcome Trust in 2012 and the other by the Global Virology Foundation in 2013, assembled academic, public health and pharmaceutical industry experts to assess the challenges and opportunities for developing antivirals for the treatment of respiratory syncytial virus (RSV) infections. The practicalities of clinical trials and establishing reliable outcome measures in different target groups were discussed in the context of the regulatory pathways that could accelerate the translation of promising compounds into licensed agents. RSV drug development is hampered by the perceptions of a relatively small and fragmented market that may discourage major pharmaceutical company investment. Conversely, the public health need is far too large for RSV to be designated an orphan or neglected disease. Recent advances in understanding RSV epidemiology, improved point-of-care diagnostics, and identification of candidate antiviral drugs argue that the major obstacles to drug development can and will be overcome. Further progress will depend on studies of disease pathogenesis and knowledge provided from controlled clinical trials of these new therapeutic agents. The use of combinations of inhibitors that have different mechanisms of action may be necessary to increase antiviral potency and reduce the risk of resistance emergence.