No abstract

The therapeutic effect of intranasally administered enviroxime was tested against naturally occurring common colds. The double-blind evaluation was carried out in Tecumseh, Mich., during a period when rhinoviruses are usually the principal pathogen. Rhinovirus transmission followed the typical pattern during this period of study. Although there were trends indicating greater therapeutic effectiveness for enviroxime when certain nasal symptoms were considered, there were no consistent statistically pignificant differences between treated and untreated groups. Results were unchanged when illnesses in different periods or associated with rhinovirus isolation were examined. It was concluded that no therapeutic effect of enviroxime was demonstrated.Although enviroxime [2-amino-1-(isopropylsulfonyl)-6-benzimidazole phenyl ketone oxime] has been shown to be effective against rhinovirus replication in vitro (1), conflicting evidence has been presented on its efficacy in preventing or treating human infections. For example, Phillpotts et al. (5) showed a reduction in rhinorrhea and shedding of rhinovirus type 9 in a prophylactic challenge trial during which enviroxime was administered to volunteers both intranasally (284 ,ug) and orally (25 mg) four times a day. In contrast, Hayden and Gwaltney (2) did not find differences in infection or illness in a prophylactic trial during which 284 ,ug of enviroxime was given intranasally five times a day against a challenge of rhinovirus type 39; in this study, no oral drug was given. In a recent report in which intranasal enviroxime was tested in therapy against rhinovirus challenge, Phillpotts et al. (6) administered six daily intranasal doses and found a significant improvement on day 5 of the trial. They suggested that larger numbers of individuals might be needed before a significant therapeutic effect could be unequivocally demonstrated and that a large-scale field trial to evaluate conditions of natural infection would be more realistic in testing enviroxime.For this reason, a therapeutic trial of enviroxime was carried out against natural infection in an open population.