Study design considerations for ribavirin: efficacy studies

Abstract

Five placebo-controlled double-blind studies, each including approximately 30 subjects, have addressed the question of the effect of aerosolized ribavirin on the course of RSV lower respiratory infection in infancy. The fact that each was able to establish a beneficial effect despite the small number of subjects studied is convincing evidence that such an effect exists. The studies from Rochester using oximetry and an analog illness severity scale indicate that this effect is both statistically significant and clinically relevant. These tools are reliable and easily applicable measures for multicenter studies when illness severity is selected as an outcome measure. Characteristics that should be taken into consideration when assigning experimental groups include age, sex, a history of prematurity or underlying conditions and arterial oxygen saturation. Future studies will address additional questions about the efficacy of ribavirin, such as its role in critically ill children, the economic benefits of its use in terms of duration of hospitalization, the usefulness of early treatment of RSV disease in high risk infants, and the impact of treatment on long-term consequences of RSV infection. These studies may require outcome variables and subject selection strategies different from those used in earlier studies.