Safety and Effectiveness of Palivizumab in Children at High Risk of Serious Disease Due to Respiratory Syncytial Virus Infection: A Systematic Review

One-year observational study of palivizumab prophylaxis on infants at risk for respiratory syncytial virus infection in Latin America

OBJECTIVE

This study aims to describe real world palivizumab use and effectiveness in high-risk Latin American infants and young children.

METHOD

Prospective, multicenter observational study with infants at risk for severe RSV infection who received palivizumab according to routine clinical practice. Subjects were followed for one year with monthly visits after the first dose of palivizumab. An infant was considered adherent if receiving all the expected injections or five or fewer injections within appropriate inter-dose intervals. Annual incidence rates and risk factors of lower respiratory tract infection (LRTI) hospitalization were determined through Poisson regression models (α=0.05).

RESULTS

The study enrolled 458 children from seven countries in Latin America, from February 2011 to September 2012. The majority (98%) were born <36 weeks gestation. Overall, patients received 83.7% of their expected injections and 86.7% completed one year of follow-up. Of the 61 LRTI hospitalizations, 12 episodes were due to RSV infection. The RSV-associated hospitalization rate was 2.9 per 100 patient-years. Bronchopulmonary dysplasia was identified as an independent risk factor for LRTI hospitalization. A total of 1165 adverse events were recorded during one year of follow-up. One hundred and two patients (22.3%) had a total of 135 serious adverse events, but no events were considered to be related to palivizumab.

CONCLUSIONS

The rate of RSV hospitalization in high-risk infants in Latin America was low and aligned with those observed in randomized control trials and observational studies. Palivizumab prophylaxis appeared effective and had a good safety profile in this population.

Systematic Review of the Safety and Efficacy of Palivizumab among Infants and Young Children with Cystic Fibrosis

BACKGROUND

Respiratory syncytial virus (RSV) is a common pathogen in infants with cystic fibrosis (CF). The use of palivizumab prophylaxis for RSV infection as the standard of care for infants with CF remains controversial.

OBJECTIVE

To evaluate the efficacy of palivizumab in reducing the incidence of RSV hospitalization in children with CF who are younger than 2 years.

METHODS

Four electronic databases (PubMed, Embase, CINAHL, and CENTRAL) were searched from inception until January 31, 2017, for clinical studies investigating the use of palivizumab in infants with CF aged less than 2 years. The primary outcome was hospitalization rate due to RSV infection. Secondary outcomes included hospitalization for respiratory illness, length of hospital stay, safety (adverse effects), and cost-effectiveness of palivizumab prophylaxis.

RESULTS

The review included a total of 10 studies (six cohort studies, two before-and-after studies, one cross-sectional study, and one randomized controlled trial) involving 3891 patients with CF. Seven studies reported that palivizumab prophylaxis had a positive impact on the rate of RSV hospitalization. Five studies (n=3404) reported that palivizumab prophylaxis significantly reduced the rate of hospitalization due to RSV infection compared to no prophylaxis. One study (n=5) demonstrated patients with CF who received palivizumab had no RSV hospitalization. Another study showed infants with CF receiving palivizumab (n=117) had a lower risk of hospitalization for RSV infection compared with premature infants (gestational age < 35 completed weeks) who received palivizumab (n=4880).

CONCLUSIONS

Evidence from the literature suggests that palivizumab may have a potential role in reducing RSV hospitalization in children aged less than 2 years with CF. Given the lack of overall data, additional research is warranted to better understand the efficacy and safety of prophylactic palivizumab in infants with CF.

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

BACKGROUND

Respiratory syncytial virus hospitalization (RSVH) rates in children <2 years of age with hemodynamically significant congenital heart disease (HSCHD) are 2- to 4-fold higher compared with healthy term infants. Pediatric recommendations differ as to whether palivizumab is beneficial beyond 1 year of age. The objective of this study was to determine whether differences exist in respiratory-related illness hospitalization (RIH) and RSVH in HSCHD infants receiving palivizumab during the first year versus second year of life in the Canadian Registry of Palivizumab.

METHODS

The Canadian Registry of Palivizumab is a prospective database of infants who received ≥1 dose of palivizumab in 32 hospitals from 2005 to 2015. Demographic data were collected at enrollment and RIH events recorded monthly. Infants <24 months of age with HSCHD were recruited.

RESULTS

Of 1909 HSCHD infants, 1380 (72.3%) in the first year (mean age, 4.2 months) and 529 (27.7%) in the second year of life (mean age, 17.8 months) received prophylaxis. Baseline demographics for day-care attendance, multiple births, enrollment age and weight differed between the groups (all P < 0.05). Additionally, second year infants had a more complicated neonatal course, with significantly longer length of stay (51.2 vs. 24.9 days) compared with those in the first year. The RIH and RSVH rates in the first year were 11.2% and 2.3% and in the second year were 10.6% and 1.7%. Cox regression analysis showed similar hazard for RIH [hazard ratio, 1.9; 95% confidence interval: 0.7-4.6; P = 0.18] and RSVH [hazard ratio, 2.0; 95% confidence interval: 0.2-16.5; P = 0.52].

CONCLUSIONS

Infants in the first and second year of life had a similar RSVH hazard. These findings suggest that infants in the second year with HSCHD, who remain unstable, are equally at risk for RSVH and merit prophylaxis.

Efficacy of palivizumab prophylaxis on the frequency of RSV-associated lower respiratory tract infections in preterm infants: determination of the ideal target population for prophylaxis

Respiratory syncytial virus (RSV) prophylaxis in high-risk infants is an effective intervention for the prevention of severe disease. The aim of this study was to determine the ideal target preterm population that might benefit from palivizumab prophylaxis by establishing the main risk factors for acute RSV-related infections. Former premature infants born with a gestational age ≤37 weeks and ≤1 year of age at the beginning of the RSV season and admitted with respiratory infection were included. RSV status was evaluated by RSV strip test in all infants. RSV-positive and -negative infants were compared in terms of demographic features, risk factors, requirement of hospitalisation and palivizumab administration. A total of 202 preterm infants under 1 year of age were enrolled. The RSV test was positive in 34 (16.8%) infants. Maternal age was significantly lower in RSV-positive infants compared with RSV-negative infants (p = 0.03). RSV-positive infants were found to be significantly discharged during the RSV season (p = 0.03). RSV-positive infants required significantly higher rates of hospitalisation and need for mechanical ventilation. Of the RSV-positive infants, 28 (82%) had a gestational age ≥29 weeks. Seventeen (77%) RSV-positive infants that required hospitalisation were ≥29 weeks of gestation. All infants with a gestational age ≥29 weeks and without palivizumab prophylaxis developed RSV infection. Palivizumab prophylaxis should be implemented into guidelines to cover preterm infants with a gestational age >29 weeks. Palivizumab prophylaxis should also be considered in high-risk infants ≤6 months of age during the RSV season.

First versus second year respiratory syncytial virus prophylaxis in chronic lung disease (2005-2015)

Children aged <2 years with chronic lung disease (CLD) have a 10-fold higher risk for respiratory syncytial virus-positive hospitalization (RSVH) compared to healthy term infants. Based on the updated position statements, we compared respiratory-related illness hospitalization (RIH) and RSVH risks in CLD children who received palivizumab during the first year (FY) versus second year (SY) of life in the Canadian Registry of Palivizumab (CARESS). Demographic data were collected at enrolment and RIH events recorded monthly from 2005 to 2015. Eight hundred forty-seven FY and 450 SY children with CLD were identified. SY children had a lower gestational age (27 versus 29 weeks) and required more days of respiratory support (64 versus 43), oxygen therapy (108 versus 55), and length of stay (118 versus 73) during the neonatal course compared to FY children; all p < 0.0005. RIH rates were 12.2 (FY) and 18.2 (SY), and RSVH rates were 2.3 (FY) and 3.9 (SY). Cox regression showed similar hazards for both RIH (hazard ratio 0.9, 95% CI 0.6-1.6, p = 0.812) and RSVH (hazard ratio 1.1, 95% CI 0.4-2.9, p = 0.920).

CONCLUSIONS

SY and FY children had similar risks for RIH and RSVH. The findings imply that SY children with CLD are correctly selected for palivizumab based on neonatal illness severity and merit prophylaxis. What is Known: • Children with chronic lung disease have a 10-fold higher risk for RSV-positive hospitalization in comparison to healthy term infants and commonly receive palivizumab prophylaxis as a preventative measure against serious RSV-related lower respiratory tract infections. • The American Academy of Pediatrics [ 2 ] and the Canadian Paediatric Society [ 30 ] have recently modified their recommendations for RSV prophylaxis in children with chronic lung disease, limiting palivizumab to either those <32 weeks gestation or those in the first year of life who are oxygen dependent or require medical therapy for the treatment of their condition. What is New: • Children with chronic lung disease receiving an additional course of palivizumab in their second year of life were determined to be at similar risk for both respiratory illness-related hospitalization and RSV-positive hospitalization as palivizumab-naïve children enrolled in the first year of life in the Canadian Registry for palivizumab (CARESS). • CARESS physicians are correctly identifying high-risk children with chronic lung disease in their second year of life, whom they believe will benefit from an additional year of palivizumab prophylaxis, based on neonatal illness severity.

RSV N-nanorings fused to palivizumab-targeted neutralizing epitope as a nanoparticle RSV vaccine

Respiratory syncytial virus (RSV) is the leading cause of acute respiratory infections in children, yet no vaccine is available. The sole licensed preventive treatment against RSV is composed of a monoclonal neutralizing antibody (palivizumab), which targets a conformational epitope located on the fusion protein (F). Palivizumab reduces the burden of bronchiolitis but does not prevent infection. Thus, the development of RSV vaccines remains a priority. We previously evaluated nanorings formed by RSV nucleoprotein (N) as an RSV vaccine, as well as an immunostimulatory carrier for heterologous antigens. Here, we linked the palivizumab-targeted epitope (called FsII) to N, to generate N-FsII-nanorings. Intranasal N-FsII immunization elicited anti-F antibodies in mice that were non-neutralizing in vitro. Nevertheless, RSV-challenged animals were better protected against virus replication than mice immunized with N-nanorings, especially in the upper airways. In conclusion, an N-FsII-focused vaccine is an attractive candidate combining N-specific cellular immunity and F-specific antibodies for protection.

Respiratory Syncytial Virus Infection Rates with Limited Use of Palivizumab for Infants Born at 29 to 31+6/7 Weeks Gestational Age

BACKGROUND

Immunoprophylaxis with palivizumab can reduce respiratory syncytial virus (RSV) infections and hospitalizations. Criteria in British Columbia limit the use of palivizumab to infants born at 29 to 31+6/7 weeks gestational age, which differ from guidelines of the American Academy of Pediatrics (AAP) and the Canadian Paediatric Society (CPS).

OBJECTIVE

To determine whether the limited use of palivizumab affected the frequency of hospital visits by RSV-positive infants (termed "RSV-positive hospital visits") who received approval for palivizumab and those who met the AAP/CPS criteria but did not receive approval for palivizumab.

METHODS

Data sets were generated for the period May 1, 2008, to April 30, 2011, to identify infants with gestational age of 29 to 31+6/7 weeks who were born in or transferred to the Fraser Health authority, RSV-positive results for infants less than 12 months of age who had visited Fraser Health sites and BC Children's Hospital, and palivizumab approvals. Infants were matched across these 3 data sets through their personal health numbers.

RESULTS

The study included 359 infants born at 29 to 31+6/7 weeks, of whom 297 met the AAP/CPS criteria. However, only 46 of these 297 received approval for palivizumab according to the BC criteria. Sixteen (4.5%) of the 359 infants had RSV-positive hospital visits during the RSV season (November through March). Of the 46 infants who received approval for palivizumab, 2 (4.3%) had RSV-positive hospital visits, and of the 251 who met the AAP/CPS criteria but did not receive palivizumab approval, 14 (5.6%) had RSV-positive hospital visits. Of the 359 infants, 6 (1.7%) had RSV-positive results while admitted to the neonatal intensive care unit, and 10 (2.8%) tested positive for RSV during a subsequent hospital visit.

CONCLUSIONS

The frequency of RSV-positive hospital visits did not differ between infants who received and those who did not receive approval for palivizumab in the Fraser Health authority. Limited use of palivizumab for RSV prophylaxis led to reasonable rates of RSV-positive hospital visits in the study population.

Viral Lower Respiratory Tract Infections

Lower respiratory tract infections in children are often viral in origin. Unfortunately in this time of significant antimicrobial resistance of infectious organisms, especially bacteria, there is still a tendency for clinicians to manage a child who coughs with antibiotics. In addition, the World Health Organization (WHO) has defined “pneumonia” as a condition that only occurs in children who have “fast breathing or chest wall indrawing”. That would delineate upper respiratory tract infections from those in the lower airway. However, in addition to pneumonia another important entity exists in the lower respiratory tract that is almost always viral in origin. This condition is acute viral bronchiolitis. The concept of “acute lower respiratory tract infection” (ALRTI) has emerged and it is becoming increasing evident from a number of studies that the infectious base of both acute pneumonia (AP) and acute bronchiolitis in children has a mixed etiology of microorganisms. Therefore, whilst certain clinical phenotypes do not require antibiotics the actual microbial etiology is much less distinct.

Incidence of Respiratory Disease During the First Two Years of Life in Children with Hemodynamically Significant Congenital Heart Disease in Italy: A Retrospective Study

Children affected by hemodynamically significant congenital heart disease (HSCHD) experience severe respiratory complications that can increase the frequency of hospitalizations. The aim of the SINERGY study was to describe the incidence of respiratory diseases and to collect information on active and passive immunoprophylaxis in the first 2 years of life. In this retrospective, multicenter, and epidemiologic study, children with HSCHD were enrolled across 11 Italian sites. Children born between December 31, 2007, and December 31, 2012, were observed during their first 2 years of life. Data were collected through hospital database searches and parent interviews. Four hundred twenty children were enrolled: 51.7 % were female, 79.5 % were born full-term (≥37 weeks), and 77.6 % weighed >2500 g at birth. The most frequent heart defects were ventricular septal defect (23.1 %) and coarctation of the aorta (14.3 %). The incidence of respiratory diseases was 63.1 %. Frequent respiratory diseases not requiring hospitalization were upper respiratory tract infections (76.4 %), acute bronchitis (43.3 %), and influenza (22.1 %), while those requiring hospitalization were bronchitis and bronchiolitis (8.3 % each one). While active immunoprophylaxis was applied with wide compliance (diphtheria/pertussis/tetanus, 99.5 %; Haemophilus influenzae type b, 72.5 %; pneumococcus, 79.9 %; meningococcus, 77.4 %), only 54 % of children received respiratory syncytial virus (RSV) passive prophylaxis (palivizumab). Of the 35 hospitalizations due to bronchiolitis, 27 (77.1 %) did not receive prophylaxis against RSV, compared with 8 (22.9 %) who received prophylaxis (P < 0.0001). Children with HSCHD are at major risk of respiratory diseases. Passive immunoprophylaxis can help to prevent hospitalizations for bronchiolitis.

Palivizumab Adherence and Outcomes in Canadian Aboriginal Children

BACKGROUND

Aboriginal infants are at risk for serious respiratory infection.

OBJECTIVE

To determine the hazard rate (HR) for respiratory-related illness (RIH) and respiratory syncytial virus (RSV) specific infection hospitalization (RSVH) in Aboriginal versus non-Aboriginal children receiving palivizumab and the effect of adherence on hospitalization.

METHODS

Palivizumab recipients in the Canadian registry from 2005 to 2014 were included. Adherence was determined by the number of palivizumab doses received during the RSV season and interdose time interval. Adherence proportions between groups were compared by χ test. Cox proportional hazard analysis determined the effect of Aboriginal status and adherence on the risk of RIH and RSVH.

RESULTS

Aboriginal infants comprised 3.6% (701/19,235) of the registry. HR was 1.6 [95% confidence interval (CI): 1.3-2.0, P < 0.001] and 1.2 (95% CI: 0.7-2.2, P = 0.383) for RIH and RSVH. Aboriginal infants were 62.8% and 63.3% adherent with all recommended injections and within stipulated time intervals, respectively, whereas 81.9% (χ = 162.45, df = 1, P < 0.001) and 72.4% (χ = 27.35, df = 1, P = 0.002) of non-Aboriginal infants were correspondingly adherent. Only 39.9% of Aboriginals were perfectly adherent (adherent to total number and injection intervals), compared with 61.7% of non-Aboriginals (χ = 133.89, df = 1, P < 0.001). Even after adjustment for known risk factors, being Aboriginal and nonadherent was associated with higher RIH hazard (HR = 1.4, 95% CI: 1.1-1.8; HR = 1.3, 95% CI: 1.1-1.4, P = 0.004), respectively. Aboriginals nonadherent with interdose intervals had a 2.2-fold increased HR for RSVH (HR = 2.2, 95% CI: 1.2-4.2, P = 0.015).

CONCLUSIONS

Prophylaxed Aboriginal infants have a significantly increased RIH and RSVH hazard than non-Aboriginal infants. Improving adherence especially interdose frequency may further reduce hospitalizations in this vulnerable population.

Use of palivizumab with other infection control measures to control respiratory syncytial virus outbreaks in neonatal care units

OBJECTIVE

No guidelines exist on the use of palivizumab during outbreaks of Respiratory Syncytial Virus (RSV) in Neonatal Intensive Care Units (NICUs). We aimed to describe an outbreak of RSV in NICU settings and the role of palivizumab in controlling the outbreak.

METHODS

The index case was a 30-day-old premature infant. During the outbreak, 13 cases of RSV were confirmed by RT-PCR. All infants in the NICU received palivizumab after RSV diagnosis.

RESULTS

Of the 13 cases, seven were male; and the median (interquartile) of birth weight was 1585 (IQR: 1480-1705) g. All cases were premature under 34-weeks-gestation. Age at onset of disease varies between 10 and 160 days. Only four cases occurred after administering palivizumab and applying other infection control measures.

CONCLUSION

During nosocomial outbreaks of RSV, administration of palivizumab to all infants in NICU appears to be rational and may help contain outbreaks.

Consensus conference on the appropriateness of palivizumab prophylaxis in respiratory syncytial virus disease

Respiratory syncytial virus infection represents a clinical burden among young children under 24 months. Palivizumab is the only drug licensed in Italy for the prevention of serious lower respiratory tract disease requiring hospitalization caused by respiratory syncytial virus in children at high risk. However recommendations for palivizumab prophylaxis are heterogeneous. Not all the published documents agree about the clinical indications of palivizumab; this could lead to different clinical practices and concerns about the appropriateness of prophylaxis. These issues and the lack of evidence about palivizumab prophylaxis efficacy in specific medical conditions brought on the idea of a consensus conference on the current recommendations for the management and prevention of bronchiolitis, in order to share useful indications. The goal was to perform a review of the evidence regarding the efficacy and the safety of palivizumab and give recommendations in order to harmonize its use. A structured and validated method to conduct the consensus process was adopted. The consensus conference recommends palivizumab prophylaxis in infants born before 29 weeks and younger than 12 months at the start of the epidemic season. According to evidence from literature and experts' opinion, palivizumab prophylaxis is not recommended in preterm infants of gestational age ≥29 weeks, without co-morbidity (i.e., cardiac, bronchopulmonary diseases). The experts identified some clinical rare conditions for which the decision of prophylaxis should be entrusted to the specialists. The evaluation of the appropriateness of palivizumab prophylaxis in the single patient should be documented by the specialists. Pediatr Pulmonol. 2016;51:1088-1096. © 2016 Wiley Periodicals, Inc.

Viral Infection in the Development and Progression of Pediatric Acute Respiratory Distress Syndrome

Viral infections are an important cause of pediatric acute respiratory distress syndrome (ARDS). Numerous viruses, including respiratory syncytial virus (RSV) and influenza A (H1N1) virus, have been implicated in the progression of pneumonia to ARDS; yet the incidence of progression is unknown. Despite acute and chronic morbidity associated with respiratory viral infections, particularly in "at risk" populations, treatment options are limited. Thus, with few exceptions, care is symptomatic. In addition, mortality rates for viral-related ARDS have yet to be determined. This review outlines what is known about ARDS secondary to viral infections including the epidemiology, the pathophysiology, and diagnosis. In addition, emerging treatment options to prevent infection, and to decrease disease burden will be outlined. We focused on RSV and influenza A (H1N1) viral-induced ARDS, as these are the most common viruses leading to pediatric ARDS, and have specific prophylactic and definitive treatment options.

Anti-RSV prophylaxis efficacy for infants and young children with cystic fibrosis in Ireland

Rationale

There is limited evidence supporting the routine use of palivizumab in paediatric cystic fibrosis (CF) patients to reduce respiratory syncytial virus (RSV) infection and related hospitalisation. Despite this, anti-RSV prophylaxis is increasingly common. This is the first report from Ireland regarding palivizumab outcomes for children with CF, under 2 years old, despite the greatest prevalence of CF globally.

Methods

An audit was performed at a tertiary hospital in Ireland’s mid-West to document all children with CF, <24 months old, who received palivizumab over a five year period and comparision made with all eligible children for the prior five year period who had not received the product (also CF patients). Palivizumab was administered to both cohorts in their first year of life. Hospitalisation rates were compared using Fisher’s exact test. Incidence of RSV and Pseudomonas aeruginosa infection was recorded.

Results

A total of 19 patients who received palivizumab were included in the study; comparision was made with a retrospective control group of 30 patients. Prophylactic palivizumab did not prevent hospitalisation for 10/19 patients, 3 of whom were affected by RSV. This was significantly greater than in the control group, where no hospitalisations were recorded (p < 0.0001). P. aeruginosa was isolated in one case from the study cohort, while no P. aeruginosa was detected in the control group.

Conclusions

This study, the first of its kind from Ireland where CF prevalence is highest, does not provide unequivocal support for prophylactic use of palivizumab in CF patients under 2 years. Despite being derived from a small sample size, based on these data and complementary clinical observation, we have discontinued such prophylaxis. However, should reported incidence of RSV-related hospitalisation increase, there is scientific plausibility for appropriately powered, randomised, controlled trials of palivizumab.

Serious Adverse Events in the Canadian Registry of Children Receiving Palivizumab (CARESS) for Respiratory Syncytial Virus Prevention

OBJECTIVES

To evaluate the safety and tolerability of palivizumab for RSV prophylaxis in high-risk children in everyday practice.

METHODS

High-risk children prophylaxed against RSV infection were recruited into a prospective, observational, Canadian RSV Evaluation Study of Palivizumab (CARESS) registry with active, serious adverse event (SAE) monitoring from 2008 to 2013. SAE reports were systematically collected and assessed for severity and relationship to palivizumab. Data were analyzed by Chi-square or Fisher Exact Tests to examine group differences in proportions.

RESULTS

13025 infants received 57392 injections. Hospitalizations for respiratory-related illness (RIH) were reported in 915 patients, and SAEs other than RIH were reported in 52 patients. Of these, 6 (0.05%) patients had a total of 14 hypersensitivity reactions that were deemed possibly or probably related to palivizumab (incidence: 2.8 per 10,000 patient-months). The SAEs of 42 patients were assessed as not related to palivizumab. SAEs in the remaining 4 patients were not classifiable as their records were incomplete. There were no significant demographic predictors of SAE occurrence.

CONCLUSIONS

Under active surveillance, a small proportion of infants in the CARESS registry experienced SAEs that had a potential relationship with palivizumab and these appeared to be unpredictable in terms of onset. Palivizumab appears to be a safe and well-tolerated antibody for RSV prophylaxis in high-risk children in routine practice.

Antibodies as a source of anti-infective peptides: an update

This review focuses on antibodies (Abs) and their function in immune protection, with particular emphasis on microbicidal Abs. Some aspects of Abs and Ab-drug conjugates as targeting therapeutic agents are also discussed. The main aim, however, is devoted to Ab-derived peptides modulating functions of the immune system and to the latest experimental evidence of Abs as a source of anti-infective and antitumor peptides derived from their complementarity determining regions and constant regions.