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

• For children with RSV illness; a) the change in RACS from baseline at randomization; b) the change in oxygen saturation over time [ Time Frame: Through Day 30 ] [ Designated as safety issue: No ]
• Percentage of children who have progression of RSV illness that requires subsequent hospitalization. [ Time Frame: Through Day 30 ] [ Designated as safety issue: Yes ]

• The secondary measure will be for RSV illness the change in RACS at baseline and change in oxygen saturation
• For children that require hospitalization based on severity of RSV and change of RACS and drug levels in respiratory tract and describe progression and severity of LRI.

• The purpose of this study is to describe the effect of a single (IM) dose of motavizumab in the upper respiratory tract in children who present with RSV illness but who do not require hospitalization at the time of presentation and
• Describe the effect of a single 30 mg/kg IM dose of motavizumab in decreasing the need for hospitalization due to worsening RSV illness in children who receive outpatient treatment
• Describe the effect of a single 30 mg/kg IM dose of motavizumab on subsequent respiratory status as measured by the Respiratory Assessment Change Score (RACS) and change in oxygen saturation
• For children who require hospitalization, describe the effect of motavizumab on severity of RSV illness during hospitalization [i.e., RACS, oxygen saturation, heart rate, use of supplemental oxygen, mechanical ventilation, and duration of intensive care unit (ICU) stay]
• Describe the effect of a single 30 mg/kg IM dose of motavizumab on duration of symptoms of RSV illness (fever, coryza, cough, and parental opinion of return to normal health and activity)
• Describe the nasal concentration of motavizumab following a single 30mg/kg dose
• Describe the serum pharmacokinetics and immunogenicity of a single 30 mg/kg IM dose of motavizumab
• Describe the effect of motavizumab on markers of inflammation as measured by gene microarray and cytokine levels
• Evaluate the safety and tolerability of a single 30 mg/kg IM dose of motavizumab in the outpatient treatment of children with RSV
• Describe the progression and severity of lower respiratory infection (LRI)

This is 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 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.

• Biological: MEDI-524
  30 mg/kg of MEDI-524
  Other Name: Motivizumab
• Other: Placebo
  30 mg/kg of Placebo

• Experimental: 1
  MEDI-524
  Intervention: Biological: MEDI-524
• Placebo Comparator: 2
  Placebo
  Intervention: Other: Placebo

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/min in children < 2 months and < 50 breaths/min 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 patient'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