Safety and antiviral activity of motavizumab, a respiratory syncytial virus (RSV)-specific humanized monoclonal antibody, when administered to RSV-infected children.

Previously healthy children hospitalized with respiratory syncytial virus (RSV) received motavizumab (3, 15, or 30 mg/kg intravenously), an RSV-specific monoclonal antibody, or placebo. Safety, tolerability, motavizumab concentrations, and immunogenicity were assessed. Cultivatable RSV in the upper respiratory tract was significantly reduced with motavizumab compared with placebo day 1 post-treatment. No adverse events were considered motavizumab-related by site investigators.

Safety, tolerability, pharmacokinetics, and immunogenicity of motavizumab, a humanized, enhanced-potency monoclonal antibody for the prevention of respiratory syncytial virus infection in at-risk children.

BACKGROUND: : Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection in young children. Motavizumab is an investigational humanized monoclonal antibody for RSV prophylaxis. METHODS: : A dose-escalation study was conducted followed by assessment of safety, tolerability, serum concentrations, and immunogenicity during a second consecutive RSV season. In season 1, premature infants aged < or =6 months or children < or =24 months with chronic lung disease of prematurity received monthly motavizumab (3 or 15 mg/kg). In season 2, children who received > or =3 motavizumab doses in season 1 were randomized to receive monthly motavizumab or palivizumab 15 mg/kg. RESULTS: : Of 217 children enrolled in season 1, 211 (97.2%) received motavizumab 15 mg/kg and 205 (94.5%) patients completed the study through 90 days after the final dose. In season 2, 136 children were randomized to receive motavizumab (n = 66) or palivizumab (n = 70). The most commonly reported related adverse event was transient injection site erythema. In season 1, mean trough motavizumab concentrations were 7.9 and 50.2 microg/mL after the 3- and 15-mg/kg doses, respectively. Trough concentrations increased with repeated motavizumab dosing; a similar pattern was seen in season 2. Antimotavizumab reactivity occurred infrequently (3.3%) in season 1. In season 2, no treatment group-specific antidrug antibody was detected through 90 to 120 days after dosing with either product. CONCLUSIONS: : The pharmacokinetic profile of motavizumab was similar to that of other IgG1 antibodies. Increased adverse reactions or immunogenicity were not observed during and after a second season of treatment with motavizumab. Safety findings from these studies supported the continued development of motavizumab.

Palivizumab prophylaxis reduces hospitalization due to respiratory syncytial virus in young children with hemodynamically significant congenital heart disease.

OBJECTIVES: To evaluate the safety, tolerance, and efficacy of palivizumab in children with hemodynamically significant congenital heart disease (CHD). STUDY DESIGN: A randomized, double-blind, placebo-controlled trial included 1287 children with CHD randomly assigned 1:1 to receive 5 monthly intramuscular injections of 15 mg/kg palivizumab or placebo. Children were followed for 150 days. The primary efficacy end point was antigen-confirmed respiratory syncytial virus (RSV) hospitalization. RESULTS: Palivizumab recipients had a 45% relative reduction in RSV hospitalizations (P=.003), a 56% reduction in total days of RSV hospitalization per 100 children (P=.003), and a 73% reduction in total RSV hospital days with increased supplemental oxygen per 100 children (P=.014). Adverse events were similar in the treatment groups; no child had drug discontinued for a related adverse event. Serious adverse events occurred in 55.4% of palivizumab recipients and 63.1% of placebo recipients (P<.005); none were related to palivizumab. Twenty-one children (3.3%) in the palivizumab group and 27 (4.2%) in the placebo group died; no deaths were attributed to palivizumab. The rates of cardiac surgeries performed earlier than planned were similar in the treatment groups. CONCLUSIONS: Monthly palivizumab (15 mg/kg IM) was safe, well-tolerated, and effective for prophylaxis of serious RSV disease in young children with hemodynamically significant CHD.