Effect of Dosing Schedule on Pharmacokinetics of Alpha Interferon and Anti-Alpha Interferon Neutralizing Antibody in Mice

The influences of dosing time and dosing schedule on the plasma alpha interferon (IFN-α) concentration and the production of anti-IFN-α neutralizing antibodies were investigated in ICR male mice adapted to cycles of 12 h of light and 12 h of dark. In mice pretreated with IFN-α for 21 days, the plasma IFN-α concentrations were significantly lower than those in control mice (P < 0.01). The clearance of IFN-α and its volume of distribution obtained at steady state were significantly higher in the animals with IFN-α pretreatment than in the mice without IFN-α pretreatment. The area under the concentration-time curve and the mean residence time of IFN-α were significantly smaller in IFN-α-pretreated animals than in control animals. The plasma IFN-α levels (measured 2 h after dosing) were significantly lower in mice treated daily with IFN-α, while the anti-IFN-α neutralizing antibody levels (measured 24 h after dosing) were significantly increased on days 15 and 21 of treatment. Plasma IFN-α levels were significantly decreased in association with the production of anti-IFN-α neutralizing antibodies in mice treated with IFN-α daily at either 0900 or 2100 h. By contrast, the plasma IFN-α levels (measured 2 h after dosing) remained stable in mice treated with IFN-α at 0900 h on alternate days, while they were significantly lower after 21 days of treatment in mice treated with IFN-α at 2100 h on alternate days. These changes were associated with a significant increase in the levels of anti-IFN-α neutralizing antibodies in the latter group. The present findings suggest that an appropriate dosing schedule and/or dosing time for IFN-α may reduce the level of production of anti-IFN-α neutralizing antibodies in experimental and clinical situations.