New antiviral approved just in time for flu season

There’s a new treatment for the influenza virus, just in time for a new season of infections.

Xofluza (baloxavir marboxil) was approved in late October by the U.S. Food and Drug Administration (FDA) for treatment of acute, uncomplicated influenza in patients aged 12 and older who have been symptomatic for no more than two days. 

The first flu treatment approved by FDA in 20 years, Xofluza offers clinicians another option to fight the flu virus-although FDA officials warn that this treatment is not a substitute for annual flu vaccination.

The antiviral treatment, taken as a single oral dose, has been shown in clinical trials to reduce the duration of flu symptoms by 23 to 28 hours. Adverse reactions to the treatment included diarrhea and bronchitis, according to FDA.

Debra Birnkrant, MD, director of the Division of Antiviral Products in the Office of Antimicrobial Products for the FDA, said Xofluva will be added to the standard arsenal of medications used to treat the flu- oseltamivir, zanamivir, and peramivir. While there is no real cure for the flu, Birnkrant said, Xofluva may help lessen the severity and duration of infection, like other treatments.

“We know that when started within 48 hours of flu symptoms, antiviral drugs can lessen symptoms and shorten the time patients feel sick,” Birnkrant said. “Having more treatment options that work in different ways to attack the virus is important because flu viruses can become resistant to antiviral drugs.”

Priority review and final approval of the new medication was granted to Japan’s Shionogi & Co., Ltd., but Xofluva is being developed and commercialized globally with the Roche Group, including Genetech in the U.S. Doses are expected to be available to clinicians in the coming weeks.

Mark D. Eisner, MD, MPH, vice president of Product Development Immunology, Infectious Disease and Ophthalmology at Genentech, said the development of new antiviral treatments for the flu is important considering that 3 percent to 11 percent of the U.S. is infected with the flu virus each year, and more than 900,000 hospitalizations and 80,000 deaths resulted from influenza last year alone.

Eisner said Xofluza is the first single-dose oral medicine to fight the flu, and works by blocking enzymes within the flu virus to stop viral replication early in the virus’ life cycle. Other approved flu treatments must be taken in multiple doses and attack the flu virus at much later stages in their life cycle.