GAITHERSBURG, Md. - Autumn has arrived and with it will come increasing numbers of children with respiratory syncytial virus (RSV) infections. Outbreaks of RSV usually occur in the fall, winter and early spring.
This year a new drug is available for the prevention of RSV. In June, palivizumab (Synagis, MedImmune Inc.) was approved by the Food and Drug Administration (FDA) for prevention of serious lower respiratory tract disease caused by RSV in pediatric patients at high risk.
Palivizumab is the first monoclonal antibody licensed in the United States for any infectious disease. It is administered by intramuscular injection at 15 mg/kg and is given once a month during anticipated periods of RSV prevalence in the community.
Safety and efficacy of palivizumab were established in infants with bronchopulmonary dysplasia (BPD) and infants with a history of prematurity, born at or before 35 weeks gestational age. The single-use vial of palivizumab does not contain preservatives and should be administered within six hours following reconstitution.
In September, the FDA also approved the supplement to MedImmune's biologic license application to manufacture palivizumab at MedImmune's contract manufacturer, Boehringer Ingelheim Pharma KG. This manufacturing and supply agreement was established in December 1997 to supplement MedImmune's own capacity.
The safety and efficacy of palivizumab were assessed in a randomized, double-blind, placebo-controlled trial, known as the IMpact-RSV Trial, of RSV disease prophylaxis among high-risk patients age 24 months and younger with BPD, and premature birth weight patients without BPD who were 6 months of age or younger at study entry. The trial was conducted at 139 centers in the United States, Canada and the United Kingdom. The primary endpoint of the study was the incidence of RSV hospitalization.
Five hundred patients were randomized to receive five monthly placebo injections and 1,002 patients were randomized to receive five monthly injections of 15 mg/kg of palivizumab. Subjects were randomized into the study from Nov. 15-Dec. 13, 1996, and were followed for safety and efficacy for 150 days; 99% of all subjects completed the study and 93% received all five injections.
Study results indicate RSV hospitalizations occurred among 53 of 500 patients in the placebo group and 48 of 1,002 patients in the palivizumab group, which represents a 55% reduction (P< 0.001).
The reduction in RSV hospitalization was observed both in patients enrolled with a diagnosis of BPD and patients enrolled with a diagnosis of prematurity without BPD. The package insert indicated that the reduction in hospitalizations was observed throughout the RSV season.
Overall, the data do not suggest that RSV illness was less severe among patients who received palivizumab and who required hospitalization due to RSV infection than among placebo patients who required hospitalization for RSV infection.
The most commonly reported events associated with administration of palivizumab included upper respiratory infection (52.6%), otitis media (41.9%), rhinitis (28.7%), rash (25.6%), pain (8.5%), hernia (6.3%) and pharyngitis (2.6%), according to the package insert.
The safety and efficacy of palivizumab have not been demonstrated for treatment of established RSV disease.
For your information:
- The IMpact-RSV Study Group. Palivizumab, a humanized respiratory syncytial virus monoclonal antibody, reduces hospitalization from respiratory syncytial virus infection in high-risk infants. Pediatrics 1998;102:531-537.
- AAP. In: Peter G, ed. 1997 Red Book: Report of the Committee on Infectious Diseases 24th ed. Elk Grove Village IL: American Academy of Pediatrics, 1997:443-448.
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