Novel anti-influenza A virus inhibitor works in patients with uncomplicated flu infection

Treatment with the anti-influenza A virus inhibitor onradivir is safe and leads to symptom improvement and viral load reduction in adults with uncomplicated influenza infection, according to data from a phase II trial.

The trial included 171 adults (median age 22 years) with an influenza-like illness screened by rapid antigen testing at the first clinical visit, had fever (axillary temperature ≥38.0 °C), and had at least one moderate systemic and one respiratory symptom within 48 h of symptom onset. None of the patients were pregnant, allergic to onradivir, or had received any influenza antiviral medication within 7 days before enrolment.

The patients were randomly assigned to receive one of the following treatments: onradivir 200 mg twice per day (n=43), onradivir 400 mg twice per day (n=43), onradivir 600 mg once per day (n=43), and a matching placebo (n=42). Treatment was given for 5 days, initiated within 48 hours after symptoms onset.

In the modified intention-to-treat population, the primary outcome of time to improvement in influenza symptoms was shorter in all three onradivir groups than in the placebo group (46.92 hours with 200 mg twice per day, 54.87 hours with 400 mg twice per day, and 40.05 hours with 600 mg once per day vs 62.87 hours). The median difference of –22.82 hours between the onradivir 600 mg once per day group and the placebo group was significant (p=0.0330).

In terms of safety, the most frequently reported treatment-emergent adverse event was diarrhoea (42 percent), occurring in 33–65 percent of patients in onradivir-treated groups as opposed to only 10 percent of those in the placebo group. None of the patients across all treatment groups had serious adverse events.