Generic Single-Dose Flu Antiviral Gets FDA’s Blessing

The FDA this week approved the first generic version of baloxavir marboxil (Xofluza) as a single-dose option to treat or prevent influenza in adults and children 5 years and up.

In the treatment setting, the single-dose tablet is indicated for acute uncomplicated influenza within 48 hours of symptom onset. Baloxavir can also be used as prophylaxis after exposure to the flu.

“Today’s approval marks a meaningful milestone for the treatment of influenza,” said Iilun Murphy, MD, the director of the FDA’s Office of Generic Drugs. “Expanding patient access to drugs and improving their ease of use are critical public health imperatives, particularly given that influenza alone accounts for millions of illnesses in the U.S. each year.”

Previous generic antiviral approvals for the flu, such as oseltamivir (Tamiflu), involve multiple days of treatment — though oseltamivir can be given to patients as young as 1 year.

Baloxavir was a standout in a recent meta-analysis of randomized trials that found most flu antivirals had little or no effect on key clinical outcomes. Baloxavir was found to likely reduce the risk of hospital admission in high-risk patients and probably reduce symptom duration.

Research on the antiviral has also demonstrated it can significantly reduce household transmission of influenza. In a recently published randomized study, the adjusted incidence of laboratory-confirmed influenza occurred in 9.5% of patients 5 days after taking a single prophylactic dose of baloxavir compared with 13.4% in a placebo group. And some research suggests it’s better than oseltamivir for stopping household transmission.

Common side effects observed in patients taking baloxavir include diarrhea, nausea, bronchitis or sinusitis, and headache. FDA also noted that the antiviral carries a warning about an increased incidence of treatment-emergent resistance in children under 5 years.