Study to Assess the Immune Reactivity of the Liquid and Lyophilized Formulations of Palivizumab (MEDI-493, Synagis)

The approved liquid formulation of palivizumab was developed to simplify preparation of the
drug before injection. Both formulations of palivizumab have been shown to be bioequivalent
in children 6 months of age or younger with a history of chronic lung disease. In previous
studies of liquid palivizumab, immunogenicity was evaluated up to 2 months after dosing in
adults, and 1 month after dosing in children. In this study, MI-CP116, immunogenicity will be
evaluated between 4 and 6 months after the last dose of study drug, in order to provide data
at a time point significantly distant from dosing when drug interference is minimal.

Inclusion Criteria:

- Medically stable child with chronic lung disease of prematurity who is ≤24 months of
age at randomization OR child with premature birth (gestational age ≤35 weeks or less)
and who is 6 months of age or younger at randomization

- Written informed consent obtained from the patient's parent(s) or legal guardian(s)

- The child must be able to complete the follow-up visit 4-6 months after the last dose
of study drug

Exclusion Criteria:

- Hospitalization at the time of randomization (unless discharge is anticipated within 3
weeks)

- Be receiving mechanical ventilation at the time of study entry (including CPAP)

- Congenital heart disease (children with uncomplicated CHD [e.g., PDA, small septal
defect] and children with complicated CHD who are currently anatomically and
hemodynamically normal can be enrolled).

- Mother with HIV infection (unless the child has been proven to be not infected)

- Life expectancy <6 months

- Known allergy to Ig products

- Acute respiratory or other acute infection or illness

- Previous reaction to IGIV, blood products, or other foreign proteins

- Receipt of lyophilized palivizumab, RSV-IG IV, or other RSV-specific monoclonal
antibody, or any other polyclonal antibody (for example, Hepatitis B IG, IVIG, VZIG)
within 3 months prior to randomization

- Any previous receipt of MEDI-524

- Participation in other investigational drug product studies