Evaluation of the safety of palivizumab in the second season of exposure in young children at risk for severe respiratory syncytial virus infection.
BACKGROUND
Palivizumab reduces respiratory syncytial virus (RSV) hospitalisations in high-risk infants. Those with severe bronchopulmonary dysplasia may require two seasons of prophylaxis. There is concern that this humanised antibody might cause an adverse immune response in a second season of use.


OBJECTIVE
To evaluate and compare the occurrence of anti-palivizumab antibodies and clinical adverse events in subjects receiving monthly palivizumab injections for a first and second season, and to assess frequency and severity of RSV disease in the two groups.


METHODS
Subjects aged <or=2 years at severe risk for RSV disease were designated as first season (no previous palivizumab exposure) or second season subjects (received palivizumab in previous RSV season). Palivizumab injections (15 mg/kg) were administered monthly for up to 5 months. Anti-palivizumab antibody titres and serum palivizumab concentrations were measured; adverse events were recorded.


RESULTS
No first (n = 71) or second (n = 63) season subjects experienced a significant anti-palivizumab antibody response (titre >or=1 : 80). Serum palivizumab concentrations were similar for the two groups. Nine (12.7%) first season and 8 (12.7%) second season subjects experienced one or more serious adverse events; most were respiratory and all were considered to be not or probably not related to palivizumab. No deaths occurred during the study.


CONCLUSIONS
Monthly palivizumab injections were not associated with adverse immune responses or adverse events in young children receiving palivizumab for one or two seasons. Children receiving palivizumab for a second season did not experience more severe adverse events than those receiving it for the first time.
Lacaze-Masmonteil
Thierry
T
Service de Pédiatrie et Réanimation Néonatales, Hôpital Antoine Béclère, Assistance Publique/Hôpitaux de Paris, Clamart, France.
Seidenberg
Juergen
J
Mitchell
Ian
I
Cossey
Veerle
V
Cihar
Martin
M
Csader
Michal
M
Baarsma
Rienk
R
Valido
Marques
M
Pollack
Paul F
PF
Groothuis
Jessie R
JR
D000911:Antibodies, Monoclonal / Q000009:adverse effects* / Q000097:blood / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D016009:Chi-Square Distribution; D004334:Drug Administration Schedule; D004341:Drug Evaluation / Q000379:methods; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D000069455:Palivizumab; D018357:Respiratory Syncytial Virus Infections / Q000097:blood / Q000188:drug therapy* / Q000276:immunology; D012307:Risk Factors; D012621:Seasons; D018709:Statistics, Nonparametric
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000069455:Palivizumab