A Study to Evaluate a Single Intramuscular Dose of Motavizumab to Treat Children With Respiratory Syncytial Virus (RSV) Illness

A Phase 2, Randomized, Double-blind, Placebo-controlled Study to Evaluate a Single Intramuscular Dose of Motavizumab (MEDI-524), a Humanized Enhanced Potency Monoclonal Antibody Against Respiratory Syncytial Virus (RSV), for the Outpatient Treatment of Children With RSV Illness

This was a Phase 2, randomized, double-blind, placebo-controlled, multicenter study to determine the effect of a single 30 mg/kg intramuscular (IM) dose of motavizumab on viral load and motavizumab levels in the upper respiratory tract of children who present with RSV illness but who do not require hospitalization. Using 1:1 randomization, 30 mg/kg motavizumab or placebo will be administered as soon as possible after a child's diagnosis of RSV and his/her eligibility for the study has been confirmed.

This was a Phase 2, randomized, double-blind, placebo-controlled, multicenter study to determine the effect of a single 30 mg/kg IM dose of motavizumab on viral load in the upper respiratory tract of children who present with RSV illness but who do not require hospitalization. Participants were randomly assigned in a 1:1 ratio to 30 mg/kg motavizumab or placebo as soon as possible after a child's diagnosis of RSV and his/her eligibility for the study had been confirmed. Randomization was stratified by age (<6 months and greater than or equal to 6 to less than or equal to 12 months of age) and by site. Enrollment of an initial 100 children (50 per treatment group) will take place at multiple sites beginning in the 2006-2007 RSV season. The study was terminated early due to inability to enroll the planned number of participants.

Inclusion Criteria:

• Previously healthy
• Age ≤12 months at the time of randomization
• Weight ≤10 kg at the time of randomization
• Gestational age ≥36 weeks
• RSV illness (must have coryza) documented by a positive RSV test at the time of evaluation
• Documented stable clinical condition that does not require hospitalization (oxygen saturation ≥ 95%; respiratory rate < 60 breaths/minute in children < 2 months and < 50 breaths/minute in children 2-12 months)
• Respiratory Distress Assessment Instrument (RDAI) score of ≤ 6 (there can be no more than 1 point assigned for each of the 6 assessment categories) at baseline evaluation
• Randomization within 4 hours of being evaluated with a positive Binax® RSV test
• Written informed consent obtained from the participant's parent(s) or legal guardian

Exclusion Criteria:

• Prior receipt of or receiving treatment with steroids (except topical steroids) prior to randomization
• Prior medically diagnosed RSV infection
• Prior receipt of or receiving anti-viral treatment for the current episode of RSV infection prior to randomization
• Any medically significant underlying ongoing chronic illness or organ system dysfunction or other known acute illness, other than the acute RSV infection
• Known renal impairment, hepatic dysfunction, hematologic abnormalities, seizure or other neurologic disorder or immunodeficiency
• Requirement for supplemental oxygen (brief use of oxygen in the immediate postnatal period to treat a transient condition is allowed)
• Mechanical ventilation at any time prior to the onset of the current RSV infection
• Congenital heart disease [children with medically or surgically closed patent ductus arteriosus (PDA), small atrial septal defect (ASD) or small ventricular septal defect (VSD) will be allowed]
• Previous reaction to intravenous immunoglobulin (IVIG), blood products, or other foreign proteins
• Prior use of IVIG, RSV-IGIV (RespiGam®), motavizumab or other immunoglobulin products within the past 2 months
• Prior use of palivizumab (Synagis®) within the past 2 months
• Currently receiving other investigational agents or have received any other investigational agents within the last 3 months
• Prior or current participation in any investigational study with a therapeutic agent or vaccine for RSV