Proving a point brings its own perils

Aviron on Saturday presented positive results of a Phase III trial of its FluMist influenza vaccine in healthy working adults. But the lack of statistical significance on an efficacy end point - not the purpose of the trial - could cause investors some pause come Monday morning.

The study met AVIR's goal of showing an effect on the economic cost of influenza, which could potentially enhance the company's promotional claims for the product. But the study failed to meet its clinical end point in reducing the occurence of influenza-like illness - an end point that the company knew was less specific than the gold standard of culture-confirmed influenza but chose because it was most inclusive of the types of illness that could have been treated as flu...