A Study to Evaluate the Safety of MEDI8897 for the Prevention of Medically Attended Respiratory Syncytial Virus(RSV) Lower Respiratory Track Infection (LRTI) in High-risk Children

This study is a pivotal Phase 2/3 randomized, double‐blind, palivizumab‐controlled study to evaluate the safety, pharmacokinetics (PK), anti‐drug antibody (ADA) response, and descriptive efficacy for MEDI8897 in high‐risk infants eligible to receive palivizumab when entering their first or second RSV season (Season 1 or Season 2, respectively). Approximately 900 palivizumab‐eligible infants entering their first RSV season will be enrolled into one of 2 cohorts: (1) preterm cohort, including approximately 600 preterm infants (≤ 35 weeks gestational age [GA]) without CLD/CHD, or (2) CLD/CHD cohort, including approximately 300 infants with CLD of prematurity or hemodynamically significant CHD. A minimum of 100 infants with hemodynamically significant CHD will be enrolled. Within each cohort, randomization will be stratified by hemisphere (northern, southern) and subject age at the time of Season 1 randomization (≤ 3 months, > 3 to ≤ 6 months, > 6 months).