The Food and Drug Administration has expanded the use of the antiviral drug Xofluza (baloxavir marboxil) for use in preventing influenza.

In 2018, Xofluza was the first drug to be approved in 20 years for treating flu, and was indicated for patients who had symptoms for no more than 48 hours. Now the drug can be prescribed to patients 12 and older after exposure to a person with flu, but before any symptoms appear, the agency announced Monday.

Previously available in tablet form only, Xofluza now also comes in granule form for mixing in water. 

The drug is an important prevention option “just in time for a flu season that is anticipated to be unlike any other” due to the coronavirus pandemic, said Debra Birnkrant, M.D., director of the Division of Antiviral Products in the FDA’s Center for Drug Evaluation and Research.

A clinical trial in 607 subjects, 12 years of age and older, determined Xofluza’s safety and success in preventing flu post-exposure. Only 1% of participants developed a fever and at least one respiratory symptom within 10 days of receiving the drug, compared with 13% in a placebo group.