Treatment of respiratory syncytial virus infection with nebulised ribavirin and the humanised monoclonal antibody palivizumab in eight haemopoietic stem cell transplant recipients

Objectives: To assess the safety and efficacy of Palivizumab in haemopoietic stem cell transplant (HSCT) recipients with respiratory syncytial virus (RSV) who received Palivizumab between 2005 and 2007 in our centre. Background: RSV represents a common infectious complication of HSCT, with significant short and long term morbidity. If left untreated, the mortality from RSV lower respiratory tract infection (LRTI) approaches 100%. Aerosolized Ribavirin has been reported to improve survival from 0% to 60-70% and increased further to 80-90% with the addition of high titre RSV IVIg or Palivizumab. Palivizumab is a humanized monoclonal antibody against RSV that has been shown to be safe and well tolerated when used as prophylaxis in high risk infants (prematurity or bronchopumonary dysplasia), leading to a 55% reduction in hospitalisation. Data on its use in the setting of HSCT are limited. Methods: 8 HSCT recipients (table 1) received aerosolised Ribavirin and a single intravenous dose of 15mg/kg Palivizumab within three days of diagnosis. The choice of dose and route of administration were based on a previous phase I study in HSCT recipients. The use of Palivizumab was an individual decision of the treating physician in each case. Results: No side effects, haematological or other organ toxicities were documented for any of the patients. By polymerase chain reaction (PCR), 6 of the 8 patients became RSV negative after treatment. One tested positive 3 days after treatment and was not repeated subsequently, and the other, showed reduction of the number of RSV infected cells by immunofluorescence but again, was not repeated subsequently. Both patients improved clinically and were discharged from hospital. Two patients died; the first of neutropenic sepsis and progression of his primary haematological disease. At the time of death he was negative for RSV by PCR. The other, who had developed severe RSV LRTI requiring intubation, was negative for RSV by PCR after treatment, improved clinically and was eventually extubated, but subsequently developed Pseudomonas pneumonia to which he finally succumbed. There were no deaths attributed to RSV. (table 2) Conclusion: Our experience supports the existing evidence that Palivizumab is safe in HSCT recipients, and for the limited number of patients that were treated, there was evidence of viral clearance while no RSV related deaths occurred, suggesting that further studies are warranted in this setting.