Clinical efficacy of inhaled zanamivir for the treatment of patients with influenza B virus infection -: A pooled analysis of randomised, placebo-controlled studies

Objective: To evaluate the efficacy of zanamivir, a neuraminidase inhibitor, for the treatment of patients with influenza B. Design and Settings: This was a pooled analysis of phase II and III randomised, double-blind, placebo-controlled studies completed before or during the 1998 to 1999 winter season that investigated the efficacy of inhaled zanamivir 10mg twice daily in patients with influenza. Results: A total of 2065 patients were enrolled in eight studies; 394 (19%) of these patients were influenza B-positive. Patients with influenza B had a similar illness to those with influenza A. Influenza B-positive patients were alleviated of their symptoms 2.0 days faster (4.0 days vs 6.0 days; p < 0.001) and returned to normal activities 1.5 days quicker (5.5 days vs 7.0 days; p < 0.001) when treated with zanamivir compared with placebo. A similar efficacy was observed in zanamivir-treated patients with influenza A infection. Conclusions: This analysis confirms that zanamivir is effective for the treatment of patients with influenza B virus infection.