Safety of palivizumab in preterm infants 29 to 32 weeks' gestational age without chronic lung disease to prevent serious respiratory syncytial virus infection.

Respiratory syncytial virus is an important cause of hospitalization in preterm infants. Palivizumab, a humanized monoclonal antibody against the respiratory syncytial virus fusion protein, is currently the only licensed product in Europe available for prophylaxis of respiratory syncytial virus lower respiratory tract infection. This study was conducted to obtain additional European data on the safety of palivizumab in preterm infants 29-32 weeks' gestational age without chronic lung disease. Subjects less than 6 months old were enrolled between October 2000 and April 2001. Demographic information was obtained and physical examination was performed at enrollment. Subjects received 15 mg/kg palivizumab intramuscularly every 30 days for the duration of the respiratory syncytial virus season. Subjects hospitalized for respiratory illness were tested for respiratory syncytial virus infection with respiratory syncytial virus rapid antigen tests. At monthly visits, interim history for adverse events/respiratory illness and physical exam was performed. A total of 285 subjects were enrolled from 35 centers in 18 countries. The mean (+/-SD) gestational age was 30.8+/-1.1 weeks, the mean birth weight 1.5+/-0.4 kg, and 56% were <12 weeks of age at enrollment. Over 80% of patients received at least four palivizumab doses; all received at least one dose. The most commonly reported adverse events (>5%) were rhinitis, increased cough, fever, pharyngitis, bronchiolitis, and diarrhea. Only six subjects reported adverse events that were considered possibly related to palivizumab. No deaths were reported. Twenty subjects were hospitalized during the study; six of these were respiratory syncytial virus positive. Palivizumab is safe and well tolerated in preterm infants 29-32 weeks' gestation without chronic lung disease.