By day 3, they felt 40 percent better than the others. In September, Hayden began another comparison study to accumulate the kind of detailed data needed by the FDA to decide whether to approve pleconaril pills for colds. If that study pans out and the pills are approved, they will almost certainly be used for more than colds. For instance, experts expect they will work on what are called summer colds or summer flu. This is not really the flu but a bad, lingering, often feverish cold that hits in the summer or fall.
Enteroviruses are a frequent culprit.
Before any drug is routinely given to millions of mildly ill people, however, the FDA must be convinced it is extremely safe. In testing so far, pleconaril seems to be free of side effects. Problems like upset stomachs happen just as often in people on dummy pills as in those getting the drug. Dr. Catherine Laughlin, chief of virology at the National Institute of Allergy and Infectious Disease, says if pleconaril does do rare unwanted things, they may not be noticed until it is already in wide use. But since the drug thwarts a biological process that is unique to viruses, human ill effects are unlikely, at least in theory.