438. Association between Palivizumab Level and Probability of Respiratory Syncytial Virus Admission to the Pediatric Intensive Care Unit among High-Risk Infants
Session: Poster Abstract Session: Pediatric Infections
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
  • 438 poster.pdf (1.2 MB)
  • Background: Palivizumab, an RSV-specific monoclonal antibody, has been shown to reduce RSV hospitalizations (RSVH) in high-risk children when administered monthly during the RSV season. Although efficacy has been demonstrated, no specific protective level has been established in humans. This analysis assessed whether palivizumab level (PL) at the time of RSVH correlated with disease severity.

    Methods: A previous large, multicenter clinical trial evaluated palivizumab efficacy (15 mg/kg intramuscular, monthly) versus placebo in preterm infants (≤35 weeks gestational age) ≤6 months old and children ≤24 months old with bronchopulmonary dysplasia (BPD). Serum PL were collected at the time of RSVH. In the current analysis, pediatric intensive care unit (PICU) admission was used as a marker of severity. PLs were compared for PICU and non-PICU subjects. Multivariate regression examined PL, age, BPD, sex, race, and gestational age as independent predictors of PICU admission.

    Results: 42 of 48 (87.5%) palivizumab recipients with an RSVH had a PL drawn; 11 required PICU admission, all of whom were preterm infants with BPD. PL were drawn on days 0–7 (mean 1.9 days) of the RSVH for non-PICU subjects and days 0–5 (mean 1.6 days) for PICU subjects. Median PL for PICU subjects were 47.82 μg/mL versus 96.53 μg/mL for non-PICU subjects (P=0.0022, Wilcoxon test); results were similar when limited to only subjects with BPD. The probability of PICU admission fell with higher PLs; there were no PICU admissions with levels ≥92 μg/mL. The association between PL and PICU admission risk remained significant in multivariate regression (HR 0.59 for log2 PL and PICU admission, P=0.029). Length of PICU stay decreased as the PL increased, although this association was not statistically significant.

    Conclusion: Among palivizumab recipients with an RSVH, serum PL was a significant predictor of PICU admission. No PICU admissions were observed in infants with a PL ≥92 μg/mL.

    Michael Forbes, MD1, Veena Kumar, MD, MPH2, Ram Yogev, MD3, Herve Caspard, MD, ScD2, Xionghua Wu, PhD2 and Christopher Ambrose, MD2, (1)Department of Pediatrics, Akron Children’s Hospital, Akron, OH, (2)MedImmune, LLC, Gaithersburg, MD, (3)Department of Pediatrics, Ann & Robert Lurie Children’s Hospital of Chicago, Chicago, IL


    M. Forbes, MedImmune: Investigator, Scientific Advisor and Speaker's Bureau, Speaker honorarium

    V. Kumar, MedImmune: Employee, Stock

    R. Yogev, None

    H. Caspard, MedImmune: Employee, Salary

    X. Wu, MedImmune, LLC: Employee, Salary

    C. Ambrose, MedImmune: Employee, Salary

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