Safety and efficacy of palivizumab prophylaxis in children with congenital heart disease

Background: Infants with congenital heart diseases (CHD) are at high risk for Respiratory syncytial virus (RSV) infection, which causes severe respiratory distress. Palivizumab, an anti-RSV monoclonal antibody, was licensed in the USA, Europe and Canada, and a large-scale placebo-controlled double-blind test in these countries confirmed its efficacy and safety. A survey using questionnaires to assess usage, prophylactic efficacy, and safety of palivizumab in Japanese infants and young children with CHD was conducted. Methods: The survey was conducted between October 2002 and March 2003. The questionnaire asked for patients' characteristics, presence of CHD, underlying diseases, starting date and number of injection, adverse events, correlation between adverse events and treatment with palivizumab, and evaluation of efficacy. Results: In total, 108 infants were reported from 61 institutions. A total of 60 of the 108 infants evaluated without major non-cardiac complications received intramuscular injection of 15 mg/kg per month of palivizumab in a manner not consistent with approved indications for this drug. A total of 43 cases (39.8%) had complexed CHD, while 64 cases (59.3%) had the first injection in October or November. The average number of injections was 3.0 +/- 1.4. Seven children (6.5%) had notable respiratory infections confirmed by positive test for RSV antigen, and five (4.6%) were hospitalized. No children died nor received mechanical ventilation. The number of adverse events was nine in five cases. There was no significant relationship between adverse events and treatment with palivizumab. Conclusion: Palivizumab is well-tolerated, fairly effective and safe in preventing severe RSV infection in infants and young children with CHD.