On October 24, 2018, the U.S. Food and Drug Administration approved Xofluza (baloxavir marboxil) for the treatment of acute uncomplicated influenza (flu) in patients 12 years of age and older who have been symptomatic for no more than 48 hours19,20. It is the first new antiviral flu treatment with a novel mechanism of action approved by the agency in nearly 20 years.

The FDA approval is based on the clinical efficacy and safety data from a phase II study conducted in Japan and phase III study (CAPSTONE-1) conducted in Japan and the U.S. in otherwise-healthy patients. A single dose of XOFLUZA significantly reduced the duration of influenza symptoms compared to placebo and demonstrated clinical efficacy which was not significantly different from that of oseltamivir with twice-daily doses administered for 5 days.

About Influenza (Flu)

Influenza (flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness. Seasonal and pandemic influenza remains a major public health concern, and novel influenza drugs that will offer significant improvement over current therapy are urgently needed. Globally, annual epidemics result in 3 to 5 million cases of severe disease, millions of hospitalizations and up to 650,000 deaths worldwide.

In the U.S., an estimated 3-11 percent of the U.S. population gets the flu each year, and it can be very serious, resulting in hospitalization or even death. In the 2017/2018 flu season, more than 900,000 people were hospitalized, and more than 80,000 people died in the U.S. Since 2010, the Center for Disease Control and Prevention (CDC) estimates that the flu has resulted in 9.2 to 35.6 million illnesses, 140,000 to 900,000 hospitalizations and 12,000 to 80,000 deaths.

About XOFLUZA (baloxavir marboxil)

XOFLUZA is a first-in-class, single-dose oral medicine with a novel mechanism of action that inhibits capdependent endonuclease in the polymerase acidic (PA) protein (in the United States Prescribing Information, this enzyme is stated as polymerase acidic endonuclease), an enzyme essential for viral replication. The regimen for XOFLUZA is a single-oral dose to treat uncomplicated influenza, which is different from all currently available antiviral treatments.

Note – XOFLUZA was discovered and developed by Shionogi. Shionogi and the Roche Group, which includes Genentech in the U.S., have a license and collaboration agreement to further develop and commercialize XOFLUZA globally. Under the terms of this agreement, Genentech has development and commercialization rights of XOFLUZA. In the U.S. XOFLUZA will be available across the U.S. in the coming weeks.

XOFLUZA was already approved and is now available in Japan for the treatment of influenza Types A and B in adults and pediatric patients. Shionogi also submitted an NDA for XOFLUZA in Taiwan on June 29, 2018, for the treatment of influenza in patients 12 years of age and older.


19. https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm624226.htm

20. http://www.shionogi.co.jp/en/company/news/2018/pmrltj0000003xss-att/e_181025.pdf

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