Comparing First- and Second-year Palivizumab Prophylaxis in Patients With Hemodynamically Significant Congenital Heart Disease in the CARESS Database (2005-2015)

Effectiveness and Safety of Palivizumab for the Prevention of Serious Lower Respiratory Tract Infection Caused by Respiratory Syncytial Virus: A Systematic Review

OBJECTIVE

Palivizumab is a humanized monoclonal antibody approved for the prevention of serious lower respiratory tract infection (LRTI) caused by respiratory syncytial virus (RSV) in infants and young children at high risk of RSV disease. This systematic review summarized evidence on the effectiveness and safety of palivizumab when used in approved populations.

STUDY DESIGN

A systematic review of Phase III trials and observational studies was conducted according to the population, intervention, comparator, outcome, timing, setting (PICOTS) approach (PROSPERO, CRD42021281380). Target populations consisted of infants with a history of premature birth (≤35-week gestational age) and children aged <2 years with bronchopulmonary dysplasia (BPD) or with hemodynamically significant congenital heart disease (hs-CHD). Outcomes of interest included RSV-related hospitalization, admission to intensive care unit (ICU), requirement for mechanical ventilation, treatment-related adverse events (AEs), and RSV-related deaths. Information sources were literature search (Ovid MEDLINE and Embase), pragmatic searches, and snowballing (covering the period up to 07 September 2021).

RESULTS

A total of 60 sources were included (5 Phase III trials and 55 observational studies). RSV-related hospitalization rates following palivizumab prophylaxis in Phase III trials were 1.8% in premature infants and 7.9% in children with BPD, which were significantly lower than rates in placebo arms. In the real-world setting, similar hospitalization rates were found (0.7-4.0% in premature infants [16 studies] and 0-5.5% in patients with BPD [10 studies]) with ICU admission reported in 0 to 33.3% of patients hospitalized for RSV. In Phase III trials, RSV-related mortality rates were 0.2 and 0.3%, while AEs occurred in 11% of premature and/or BPD patients and 7.2% of hs-CHD patients, consisting mainly of injection site reaction, fever, and diarrhea. Similar results were found in observational studies.

CONCLUSION

This systematic review supports the effectiveness and safety of palivizumab in the indicated populations.

KEY POINTS

· Systematic review supports the positive benefit-risk profile of palivizumab in the indicated populations.. · Real-world safety and effectiveness of palivizumab are consistent with Phase III trials results.. · Palivizumab reduces RSV-related hospitalizations, ICU admissions, and need for mechanical ventilation..

Reappraisal of the Subtropical Guidelines on Palivizumab Prophylaxis in Congenital Heart Disease

Objective: To define the impact of associated abnormalities on the efficacy of the novel subtropical guidelines for palivizumab prophylaxis on respiratory syncytial virus (RSV)-related hospitalizations in patients with hemodynamically significant congenital heart disease (hsCHD). Method: This prospective study enrolled every patient seen at a tertiary care center for hsCHD, who was born between 2014 and 2018 and received at least 1 dose of palivizumab, according to the subtropical guidelines. The patients were followed until the age of 2 years. Results: A total of 772 patients (49% male) were enrolled. Cyanotic CHD was seen in 46% of patients, of whom 23% had associated abnormalities. Lung/airway abnormalities (14%) were the most common followed by the genetic syndromes associated with CHD (7.3%). Among the 772 patients, RSV-related hospitalizations occurred in 3.2 and 2.2% children aged ≤ 12 and 13-24 months, respectively. Most of the RSV infections occurred in patients no longer satisfying the criteria for palivizumab prophylaxis. The patients with associated abnormalities but not the type of CHD, patient age, and patient sex were risk factors for RSV-related hospitalizations. The rates of RSV-related hospitalizations, admission to the intensive care unit, and endotracheal intubation were higher for patients with associated anomalies than for other patients before 24 months of age (10.2 vs. 4.0%, 67 vs. 33%, and 39 vs. 4.2%, p = 0.004, 0.06, 0.013, respectively). Conclusion: Children with abnormalities, especially genetic syndromes and lung/airway problems associated with CHD, are at high risk for RSV-related hospitalization. Our current subtropical guidelines for palivizumab prophylaxis in patients with hsCHD, should be revised to include the results of this study.

Challenges in the prevention or treatment of RSV with emerging new agents in children from low- and middle-income countries

INTRODUCTION

Respiratory syncytial virus (RSV) causes approximately 120,000 deaths annually in children <5 years, with 99% of fatalities occurring in low- and middle-income countries (LMICs).

AREAS COVERED

There are numerous RSV interventions in development, including long-acting monoclonal antibodies, vaccines (maternal and child) and treatments which are expected to become available soon. We reviewed the key challenges and issues that need to be addressed to maximize the impact of these interventions in LMICs. The epidemiology of RSV in LMICs was reviewed (PubMed search to 30 June 2020 inclusive) and the need for more and better-quality data, encompassing hospital admissions, community contacts, and longer-term respiratory morbidity, emphasized. The requirement for an agreed clinical definition of RSV lower respiratory tract infection was proposed. The pros and cons of the new RSV interventions are reviewed from the perspective of LMICs.

EXPERT OPINION

We believe that a vaccine (or combination of vaccines, if practicable) is the only viable solution to the burden of RSV in LMICs. A coordinated program, analogous to that with polio, involving governments, non-governmental organizations, the World Health Organization, the manufacturers and the healthcare community is required to realize the full potential of vaccine(s) and end the devastation of RSV in LMICs.

Expert consensus on palivizumab use for respiratory syncytial virus in developed countries

Respiratory syncytial virus (RSV) infection is a leading cause of hospitalisation in early childhood and palivizumab is the only licensed intervention for prevention. Palivizumab guidelines should reflect the latest evidence, in addition to cost-effectiveness and healthcare budgetary considerations. RSV experts from Europe, Canada and Israel undertook a systematic review of the evidence over the last 5 years and developed recommendations regarding prophylaxis in industrialised countries. Almost 400 publications were reviewed. This group recommended palivizumab for: preterm infants (<29 and ≤31 weeks gestational age [wGA] and ≤9 and ≤6 months of age, respectively; high-risk 32-35wGA), former preterm children ≤24 months with chronic lung disease/bronchopulmonary dysplasia, children ≤24 months with significant congenital heart disease; and other high-risk populations, such as children ≤24 months with Down syndrome, pulmonary/neuromuscular disorders, immunocompromised, and cystic fibrosis. Up to 5 monthly doses should be administered over the RSV season. It is our impression that the adoption of these guidelines would help reduce the burden of RSV.

Bronchiolitis: an update on management and prophylaxis

Bronchiolitis is an acute respiratory illness that is the leading cause of hospitalization in young children less than 2 years of age in the UK. Respiratory syncytial virus is the most common virus associated with bronchiolitis and has the highest disease severity, mortality and cost. Bronchiolitis is generally a self-limiting condition, but can have serious consequences in infants who are very young, premature, or have underlying comorbidities. Management of bronchiolitis in the UK is guided by the National Institute for Health and Care Excellence (2015) guidance. The mainstays of management are largely supportive, consisting of fluid management and respiratory support. Pharmacological interventions including nebulized bronchodilators, steroids and antibiotics generally have limited or no evidence of efficacy and are not advised by National Institute of Health and Care Excellence. Antiviral therapeutics remain in development. As treatments are limited, there have been extensive efforts to develop vaccines, mainly targeting respiratory syncytial virus. At present, the only licensed product is a monoclonal antibody for passive immunisation. Its cost restricts its use to those at highest risk. Vaccines for active immunisation of pregnant women and young infants are also being developed.

Outcomes related to respiratory syncytial virus with an abbreviated palivizumab regimen in children with congenital heart disease: a descriptive analysis

BACKGROUND

It has been hypothesized that 4 doses of palivizumab, a neutralizing monoclonal antibody against respiratory syncytial virus (RSV), administered during a fixed-date RSV season may reduce hospital admissions comparably to the standard 5-dose schedule. We report outcomes in children with congenital heart disease approved to receive this 4-dose palivizumab schedule in British Columbia.

METHODS

We performed a population-based descriptive cohort analysis of all 406 approved palivizumab courses over 4 seasons (2012/13 to 2015/16) in 325 children with hemodynamically significant congenital heart disease enrolled in the British Columbia RSV Immunoprophylaxis Program. The primary outcome was in-season hospital admission for potential RSV-related lower respiratory tract infection (LRTI). Secondary outcomes include timing of admission in relation to dosing. Analysis was by intention-to-treat.

RESULTS

Of the 406 approved palivizumab courses, 391 were administered. In 33 cases (8.4%), an additional dose was given immediately after cardiac bypass surgery. There were 17 RSV-confirmed hospital admissions (median age of children 5.9 mo [interquartile range 4-10 mo]) and 8 admissions in which the child was not tested for RSV, for a maximum of 25 potential RSV-related admissions (6.2 per 100 approvals [95% confidence interval 4.0-9.0]). Twenty-four (96%) of the 25 admissions occurred within the 4-dose palivizumab dosing period, and the remaining admission occurred 52 days after the fourth dose. Sixty-four (72%) of 89 admissions were RSV-negative; the baseline clinical characteristics of these children were not different from those of children with RSV-confirmed admissions.

INTERPRETATION

In infants with hemodynamically significant congenital heart disease, a 4-dose fixed-date palivizumab schedule over a 6-month season provided seasonal protection comparable to that in a clinical trial involving a standard 5-dose schedule. Because RSV was responsible for only 19% of admissions for LRTI in our cohort, it is critical to continue to emphasize other preventive measures, including family education toward proper hand hygiene, breast-feeding and limiting infectious exposures in children at high risk.

Respiratory virus prophylaxis in congenital heart disease

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections and causes up to 200,000 infant deaths a year worldwide. The average rate of hospitalization for severe RSV infection is 5 per 1000 children, and the rate is three-times higher in those with congenital heart disease (CHD). Palivizumab, a monoclonal antibody, reduces hospitalization rates and intensive care admissions. It is used prophylactically and is administered as monthly doses during the RSV season. Hemodynamically unstable CHD is the most susceptible CHD to a severe episode of RSV infection. This review explores current evidence surrounding therapies, patterns of infection and identifies groups which may still be vulnerable to severe RSV infection.

Past, Present and Future Approaches to the Prevention and Treatment of Respiratory Syncytial Virus Infection in Children

INTRODUCTION

The REGAL (RSV Evidence - A Geographical Archive of the Literature) series has provided a comprehensive review of the published evidence in the field of respiratory syncytial virus (RSV) in Western countries over the last 20 years. This seventh and final publication covers the past, present and future approaches to the prevention and treatment of RSV infection among infants and children.

METHODS

A systematic review was undertaken of publications between January 1, 1995 and December 31, 2017 across PubMed, Embase and The Cochrane Library. Studies reporting data on the effectiveness and tolerability of prophylactic and therapeutic agents for RSV infection were included. Study quality and strength of evidence (SOE) were graded using recognized criteria. A further nonsystematic search of the published literature and Clinicaltrials.gov on antiviral therapies and RSV vaccines currently in development was also undertaken.

RESULTS

The systematic review identified 1441 studies of which 161 were included. Management of RSV remains centered around prophylaxis with the monoclonal antibody palivizumab, which has proven effective in reducing RSV hospitalization (RSVH) in preterm infants < 36 weeks' gestational age (72% reduction), children with bronchopulmonary dysplasia (65% reduction), and infants with hemodynamically significant congenital heart disease (53% reduction) (high SOE). Palivizumab has also shown to be effective in reducing recurrent wheezing following RSVH (high SOE). Treatment of RSV with ribavirin has conflicting success (moderate SOE). Antibodies with increased potency and extended half-life are currently entering phase 3 trials. There are approximately 15 RSV vaccines in clinical development targeting the infant directly or indirectly via the mother.

CONCLUSION

Palivizumab remains the only product licensed for RSV prophylaxis, and only available for high-risk infants. For the general population, there are several promising vaccines and monoclonal antibodies in various stages of clinical development, with the aim to significantly reduce the global healthcare impact of this common viral infection.

FUNDING

AbbVie.

RSV prophylaxis guideline changes and outcomes in children with congenital heart disease

OBJECTIVE

The aim of this study was to compare inpatient outcomes and costs for children with respiratory syncytial virus and congenital heart disease before and after the change in management guidelines for respiratory syncytial virus prophylaxis.

DESIGN

Hospital discharge data from the Vizient (formerly University HealthSystem Consortium) were queried from October 2012 to June 2014 (Era 1) and July 2014 to April 2016 (Era 2) for patients aged <24 months with an any International Classification of Disease (ICD)-9 or ICD-10 code for congenital heart disease (745-747.49, Q20.0-Q26.4) and a primary or secondary admitting diagnosis of respiratory syncytial virus infection (079.6, J20.5), acute bronchiolitis due to respiratory syncytial virus (466.11, J21.0) or respiratory syncytial virus pneumonia (480.1, J12.1).

SETTING

This study is a review of a national administrative discharge database.

PATIENTS

Respiratory syncytial virus admissions were identified in 1269 patients aged <24 months with congenital heart disease, with 644 patients in Era 1 and 625 in Era 2. Patients 0-12 months old represented 83% of admissions.

INTERVENTIONS

Prior to 2014, children aged 0-24 months with congenital heart disease were eligible to receive respiratory syncytial virus prophylaxis. Updated guidelines, published in 2014, restricted the recommendation to administer palivizumab respiratory syncytial virus prophylaxis to children with congenital heart disease only if they are ≤12 months old.

OUTCOME MEASURES

The outcome measures are hospital length of stay, ICU admission rate, mortality, and direct costs.

RESULTS

There was no change in length of stay, ICU admission rate, in-hospital mortality, or direct costs for children 13-24 months old with congenital heart disease after the change in guidelines. There were no deaths in 13-24 month olds, regardless of era.

CONCLUSIONS

Our findings provide additional support for the new guideline recommendations to provide respiratory syncytial virus prophylaxis only for children ≤12 months old with congenital heart disease.

Respiratory syncytial virus hospitalization risk in the second year of life by specific congenital heart disease diagnoses

Children with hemodynamically significant congenital heart disease (CHD) are at elevated risk of morbidity and mortality due to respiratory syncytial virus (RSV) disease compared to their healthy peers. Previous studies have demonstrated lower RSV hospitalization risk among all children with CHD at 12-23 months of age versus 0-11 months of age. However, RSV hospitalization risk at 12-23 months of age by specific CHD diagnosis has not been characterized. Both case-control and cohort studies were conducted using data from the US National Inpatient Sample from 1997 to 2013 to characterize relative risk of RSV hospitalization among children 12-23 months of age with CHD. Related CHD diagnoses were combined for analysis. Hospitalizations for RSV and unspecified bronchiolitis were described by length of stay, mechanical ventilation use, mortality, and total charges. Over the 17-year period, 1,168,886 live birth hospitalizations with CHD were identified. Multiple specific CHD conditions had an elevated odds ratio or relative risk of RSV hospitalization. Mean total RSV hospitalization charges were significantly higher among children with CHD relative to those without CHD ($19,650 vs $7,939 in 2015 dollars) for this period. Compared to children without CHD, children with Ebstein's anomaly, transposition of the great arteries, aortic stenosis, heterotaxia, and aortic arch anomalies had 367-, 344-, 203-, 117- and 47-fold increased risk of inpatient RSV mortality, respectively. Unspecified bronchiolitis hospitalization odds and relative risk across CHD diagnoses were similar to those observed with RSV hospitalization; however, unspecified bronchiolitis hospitalizations were associated with shorter mean days of stay and less frequently associated with mechanical ventilation or mortality. Among children with more severe CHD diagnoses, RSV disease remains an important health risk through the second year of life. These data can help inform decisions regarding interventions to protect children with CHD from severe RSV disease during their second year of life.

Thymosin alpha 1 and HIV-1: recent advances and future perspectives

In spite of the consistent benefits for HIV-1 infected patients undergoing antiretroviral therapy, a complete immune reconstitution is usually not achieved. Actually, antiretroviral therapy may be frequently accompanied by immunological unresponsiveness, persistent inflammatory conditions and inefficient cytotoxic T-cell response. Thymosin alpha 1 is a thymic peptide that demonstrates a peculiar ability to restore immune system homeostasis in different physiological and pathological conditions (i.e., infections, cancer, immunodeficiency, vaccination and aging) acting as multitasking protein depending on the host state of inflammation or immune dysfunction. This review reports the present knowledge on the in vitro and in vivo studies concerning the use of thymosin alpha 1 in HIV-1 infection. Recent findings and future perspectives of therapeutic intervention are discussed.

Defining the Risk and Associated Morbidity and Mortality of Severe Respiratory Syncytial Virus Infection Among Infants with Congenital Heart Disease

Introduction

The REGAL (RSV Evidence—a Geographical Archive of the Literature) series provide a comprehensive review of the published evidence in the field of respiratory syncytial virus (RSV) in Western countries over the last 20 years. This fourth publication covers the risk and burden of RSV infection in infants with congenital heart disease (CHD).

Methods

A systematic review was undertaken for articles published between January 1, 1995 and December 31, 2015 across PubMed, Embase, The Cochrane Library, and Clinicaltrials.gov. Studies reporting data for hospital visits/admissions for RSV infection among children with CHD as well as studies reporting RSV-associated morbidity, mortality, and healthcare costs were included. The focus was on children not receiving RSV prophylaxis. Study quality and strength of evidence (SOE) were graded using recognized criteria.

Results

A total of 1325 studies were identified of which 38 were included. CHD, in particular hemodynamically significant CHD, is an independent predictor for RSV hospitalization (RSVH) (high SOE). RSVH rates were generally high in young children (<4 years) with CHD (various classifications), varying between 14 and 357/1000 (high SOE). Children (<6 years) with RSV infection spent 4.4–14 days in hospital, with up to 53% requiring intensive care (high SOE). Infants (<2 years) with CHD had a more severe course of RSVH than those without CHD (high SOE). Case fatality rates of up to 3% were associated with RSV infection in children with CHD (high SOE). RSV infection in the perioperative period of corrective surgery and nosocomial RSV infection in intensive care units also represent important causes of morbidity (moderate SOE).

Conclusion

CHD poses a significant risk for RSVH and subsequent morbidity and mortality. RSV infection often complicates corrective heart surgery. To reduce the burden and improve outcomes, further research and specific studies are needed to determine the longer-term effects of severe RSV infection in young children with CHD.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-016-0142-x) contains supplementary material, which is available to authorized users.