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Human rhinovirus (HRV) infections are usually self-limited but may be associated with serious consequences, particularly in those with asthma and chronic respiratory disease. Effective antiviral agents are needed for preventing and treating HRV illnesses. Ruprintrivir (Agouron Pharmaceuticals, Inc., San Diego, Calif.) selectively inhibits HRV 3C protease and shows potent, broad-spectrum anti-HRV activity in vitro. We conducted three double-blind, placebo-controlled clinical trials in 202 healthy volunteers to assess the activity of ruprintrivir in experimental HRV infection. Subjects were randomized to receive intranasal ruprintrivir (8 mg) or placebo sprays as prophylaxis (two or five times daily [2x/day or 5x/day] for 5 days) starting 6 h before infection or as treatment (5x/day for 4 days) starting 24 h after infection. Ruprintrivir prophylaxis reduced the proportion of subjects with positive viral cultures (for 5x/day dosing groups, 44% for ruprintrivir treatment group versus 70% for placebo treatment group [P=0.03]; for 2x/day dosing groups, 60% for ruprintrivir group versus 92% for placebo group [P=0.004]) and viral titers but did not decrease the frequency of colds. Ruprintrivir treatment reduced the mean total daily symptom score (2.2 for ruprintrivir treatment group and 3.3 for the placebo treatment group [P=0.014]) by 33%. Secondary endpoints, including viral titers, individual symptom scores, and nasal discharge weights, were also reduced by ruprintrivir treatment. Overall, ruprintrivir was well tolerated; blood-tinged mucus and nasal passage irritation were the most common adverse effects reported. Pharmacokinetic analysis of plasma and nasal ruprintrivir concentrations revealed intranasal drug residence with minimal systemic absorption. Results from these studies in experimental rhinoviral infection support continued investigation of intranasal ruprintrivir in the setting of natural HRV infection.

A single-dose study and a multiple-dose study of the safety and pharmacokinetics of ruprintrivir, a new selective irreversible inhibitor of human rhinovirus 3C protease, were conducted with healthy adult volunteers. Both studies were double-blind, randomized, placebo-controlled, parallel-group investigations of ruprintrivir administered intranasally at two dose levels. The parent drug and its acid metabolite, AG7185, were measured in plasma samples and nasal washings, and the safety of the treatments was monitored. Intranasal ruprintrivir, administered as single doses of 4 and 8 mg or every 3 h, six times per day, for 7 days was safe and well tolerated. Adverse events were mild, short-lived, and confined to the upper respiratory tract (i.e., nose and throat, taste and smell perceptions). Adverse events were similar after placebo and after single or multiple doses of active drug. Systemic exposure to ruprintrivir was rarely detectable with the highest measured concentration of < or =0.52 ng/ml; the assay had a lower limit of quantification of 0.2 ng/ml. Systemic exposure to the metabolite was also low, with a highest measured concentration of 3.25 ng/ml. Concentrations of AG7185 observed during multiple dosing were higher than those observed after the first dose but were no more than predicted from the single-dose study. Substantial amounts of ruprintrivir were observed intranasally for at least 9 h after multiple doses of ruprintrivir.