Respiratory syncytial virus in hematopoietic cell transplant recipients and patients with hematologic malignancies

Khawaja, Fareed; Chemaly, Roy F.

Ribavirin is a nucleoside analog that is active against a broad spectrum of RNA viruses. It acts through intercalation into the RNA virus, enhancing its mutation rate. Ribavirin is available in aerosolized, oral, and intravenous formulations. Aerosolized ribavirin was approved by the FDA for the treatment of RSV LRTI in hospitalized infants and young children in 1985 and is the most studied formulation in HCT recipients. 4, 5, 24, 42, 44, 45, 49, 53, 58, [71] [72] [73] [74] [75] [76] [77] The conventional dosing regimen is 6 g delivered over 18 h through a small particle aerosol generator, with patients in a scavenger tent to decrease environmental contamination and exposure to healthcare workers (ribavirin is teratogenic). In an alternative regimen, the same total dose of ribavirin is given but is divided into three doses per day (2 g over 3 h, 3 times a day). This intermittent regimen was shown to be equivalent to the conventional continuous regimen in an adaptive randomized trial. 78 Most of the studies on the use of ribavirin for RSV infections in HCT recipients and HM patients are retrospective in nature, lacking a comparison or control group. 26, 45, 73, 74, 79, 80 Yet cumulative evidence, albeit not from clinical trials, suggests a better outcome when ribavirin is used in HCT recipients with early disease or URTI. 4, 46, 71, 78, [81] [82] [83] A decrease in the rate of progression from RSV URTI to LRTI after aerosolized ribavirin therapy in HCT recipients with RSV infections was pronounced (from 59% to 20%) in one study. 4 A randomized control trial that was halted before completing enrollment for different reasons, including slow accrual, showed a trend towards a lower rate of progression to LRTI when aerosolized ribavirin was used. 71 Of the nine patients who were treated with ribavirin, only one experienced progression compared to two of the five patients who were not treated.