Intranasal interferon-alpha 2 treatment of experimental rhinoviral colds

The therapeutic efficacy of recombinant interferon-alpha 2 (HuIFN-alpha 2) in experimental infection with rhinovirus type 39 was assessed in two randomized, double-blind, placebo-controlled studies. Adult volunteers (serum neutralizing antibody titer, less than or equal to 1:2) were given 9 X 10(6) international units of HuIFN-alpha 2 three times a day for five days by intranasal spray (study 1) or drops (study 2) beginning 28 hr after rhinovirus inoculation. HuIFN-alpha 2 did not prevent rhinovirus infection or colds in either study. Treatment by nasal drops and to a lesser extent by spray was associated with significant reductions in duration and quantity of viral shedding. Treatment by drops was associated with significant but modest effects on nasal symptom scores and trends toward reduced quantities of production of nasal mucus. Despite lower nasal wash concentrations of interferon, HuIFN-alpha 2 drops appeared to have greater antiviral activity and therapeutic efficacy than did HuIFN-alpha 2 spray. These findings suggest that HuIFN-alpha 2 may not be therapeutically useful in treating naturally occurring rhinoviral colds.