A Phase II Randomized, Double-Blind, Two-Period Cross-Over Study to Evaluate the Pharmacokinetics, Safety and Tolerability of a Liquid Formulation of Palizvizumab (MEDI-493, Synagis)

• The child must have been born at greater than or equal to 35 weeks gestation and be greater than or equal to 6 months of age at the time of randomization (child must be randomized on or before their 6-month birthday)
• The child's parent or legal guardian must provide written informed consent; and
• The child must be able to complete the follow-up visits on Study Days 30 and 60 within the protocol specified windows (±2 days)
• Parent/legal guardian of patient has available telephone access.

Exclusion Criteria:

• Be hospitalized;
• Birth hospitalization > 6 weeks duration;
• Be receiving mechanical ventilation at the time of study entry (including CPAP);
• Bronchopulmonary dysplasia (BPD), defined as history of prematurity and associated chronic lung disease with oxygen requirement for >28 days;
• Congenital heart disease (CHD). (Children with medically or surgically corrected [closed] patent ductus arteriosus and no other CHD may be enrolled.)
• Known renal impairment, hepatic dysfunction, chronic seizure disorder, or immunodeficiency;
• Any of the following laboratory findings in blood obtained within 7 days prior to study entry:
• BUN or creatinine >1.5´ the upper limit of normal for age
• AST (SGOT) or ALT (SGPT) >1.5´ the upper limit of normal for age
• hemoglobin \<9.0 gm/dL
• white blood cell count \<4,000 cells/mm3
• platelet count \<110,000 cells/mm3
• Acute illness or progressive clinical disorder;
• History of recent difficult venous access;
• Active infection, including acute RSV infection;
• Previous reaction to IGIV, blood products, or other foreign proteins;
• Received within the past 120 days or currently receiving IGIV, other immunoglobulin products, or any investigational agents;
• Have ever received palivizumab;
• Currently participating in any investigational study; or
• Previously participated in any investigational study of RSV vaccines or monoclonal antibodies.