Efficacy of Oral Ribavirin in Respiratory Syncytial Virus Infection in Hematopoietic Stem Cell Transplant Patients: A Single-Centre Experience

Background: Respiratory syncytial virus (RSV) is one of the most commonly encountered respiratory viruses among patients who have been diagnosed with a hematological malignancy or a hematopoietic stem cell transplantation (HSCT). In immunocompromised patients including HSCT recipients, RSV can progress to a more severe lower respiratory infection (LRI), often complicated by respiratory failure leading to increased morbidity and mortality. Little is known about the best management strategy in this immunocompromised group and strategies to manage RSV is challenging. Data on aerosolized ribavirin to treat RSV infections in HSCT recipients come from small, retrospective studies with heterogeneous treatment combinations but nevertheless, have shown to prevent poor outcomes. There is very little data on oral ribavirin treatment but the retrospective data so far has been promising.

Aim: To evaluate the effectiveness of oral ribavirin in HSCT patients with RSV infection at our centre in London, Ontario.

Methods: Eighteen HSCT patients with RSV were analyzed retrospectively. In 2012, there were 5 patients treated with supportive care alone. After 2012, there were 13 patients treated with oral ribavirin. RSV diagnosis was established by polymerase chain reaction assay via nasopharyngeal swabs. Oral ribavirin was initiated at 15 mg/kg/day in three divided doses for 7-10 days with possibility of extension in persistently symptomatic patients. An immunodeficiency scoring index (ISI) was used to classify patients as low, moderate, or high risk for progression to lower respiratory infection (LRI) or death.

Findings: An outbreak of RSV occurred in our oncology unit in early 2012 where 5 HSCT patients ((3 autologous HSCT and 2 allogeneic HSCT patients) contracted RSV infection as well. No definitive treatment options were available during this period and patients were managed with supportive care alone. 4/5 HSCT patients died of RSV infection leading into an 80% mortality rate. This experience led to the development of a protocol for the HSCT patients focusing on prevention of nosocomial transmission, early PCR testing and treatment with oral ribavirin for those confirmed with RSV infection and signs of pneumonia or LRI. Since 2012, 13 HSCT patients (4 autologous HSCT patients and 9 allogeneic HSCT patients) were diagnosed with RSV infection and promptly treated with oral ribavirin. The median treatment duration was 10 days (range: 7-12). All patients treated with oral ribavirin survived the infection. Oral ribavirin was well tolerated with minor adverse effects.

Conclusion: We found that HSCT patients with lower respiratory RSV infections can be successfully managed by use of prevention strategies and oral ribavirin. Although, our experience reflects a small sample size, the protocol was associated with decreased mortality compared to patients who received supportive care alone. Our experience supports the use of oral ribavirin for the early treatment of HSCT patients with RSV associated LRI and may be an alternative to aerosolized RBV. But ongoing review of our experience with this protocol is necessary and large prospective studies are needed to determine the optimal therapy in this patient group.