Compound Name:PalivizumabMolecular Target:RSV F (fusion) proteinMolecular Structure:humanized IgG1?Licensed Indication:prevention of serious lower respiratory; tract disease caused by respiratory syncytial virus (RSV) in pediatric patients at high risk of RSV diseaseManufacturer and/or Distributor:MedimmuneInitial FDA Approval:1998Summary:Palivizumab (Synagis®) is a recombinant 95% humanized IgG1k monoclonal antibody that targets the A antigenic site on envelop fusion protein (RSV-F) of respiratory syncytial virus. Binding of palivizumab to this viral surface determinant prevents both fusion of the virus with the cell membrane, and cell-to-cell fusion of RSV infected cells. Palivizumab is indicated for the seasonal prevention of serious lower respiratory tract disease caused by RSV in pediatric patients at significantly increased risk of morbidity and mortality due to RSV infection, including infants with chronic lung disease or hemodynamically significant congenital heart disease (CHD). Palivizumab is administered by monthly intramuscular injections throughout the RSV season. Palivizumab has been used in more than one million children in the U.S. since its introduction in 1998. The safety and efficacy of palivizumab was established in infants with bronchopulmonary dysplasia (BPD), infants with a history of premature birth (≤35 weeks gestational age), and children with hemodynamically significant CHD. Per published recommendations, the first dose of palivizumab should be administered prior to commencement of the RSV season, the timing of which is dependent on geographic location. Palivizumab should be continued monthly throughout RSV season, even in patients who develop an RSV infection. There have been very rare cases of anaphylaxis (<1 per 100,000 patients) after administration of palivizumab. Rare (<1 per 1,000 patients) hypersensitivity reactions have also been reported. Reported cases of anaphylaxis and acute hypersensitivity reactions have occurred on initial exposure and following re-exposure to palivizumab. Very rare cases (<1 case per 100,000 patients) of severe thrombocytopenia (platelet count <50,000/microliter) have been reported in post-marketing surveys. Palivizumab may interfere with some RSV diagnostic tests. Palivizumab is not reported to interfere with the response to vaccines.References

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1. Palivizumab, a humanized respiratory syncytial virus monoclonal antibody, reduces hospitalization from respiratory syncytial virus infection in high-risk infants. The IMpact-RSV Study Group. Pediatrics. 1998 Sep;102(3 Pt 1):531-537.

2. From the American Academy of Pediatrics: Policy statements--Modified recommendations for use of palivizumab for prevention of respiratory syncytial virus infections. Pediatrics. 2009 Dec;124(6):1694-1701.

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6. Ambrose CS, Chen X, Kumar VR. A population-weighted, condition-adjusted estimate of palivizumab efficacy in preventing RSV-related hospitalizations among US high-risk children. Hum Vaccin Immunother. 2014 Aug 21:1-4.

7. Lavoie PM, Solimano A, Taylor R, Kwan E, Claydon J et al. Outcomes of Respiratory Syncytial Virus Immunoprophylaxis in Infants Using an Abbreviated Dosing Regimen of Palivizumab. AMA Pediatr. 2016 Feb 1;170(2):174-6.