FDA Accepts Genentech’s NDA for Xofluza for Flu Treatment in Children

genentech What are the applicable pediatric and post-exposure indications?

Response: We recently announced that the U.S. FDA has accepted a New Drug Application (NDA) as well as two supplemental New Drug Applications (sNDA) for Xofluza® (baloxavir marboxil). The FDA accepted an NDA for a new formulation of Xofluza as one-dose granules for oral suspension (2 mg/mL), potentially offering a more convenient option for children and those who have difficulty swallowing. In addition, the application seeks approval of Xofluza for the treatment of acute uncomplicated influenza in otherwise healthy children aged one to less than 12 years of age who have been symptomatic for no more than 48 hours.

The FDA also accepted an sNDA for post-exposure prophylaxis of influenza in people one year of age and older for both the oral suspension and currently-available tablet formulation. What is the background for and main findings of the underlying studies? How does Xofluza® differ from other drugs for flu treatment or prevention? 

Response: These filings are based on positive results from two Phase III studies, miniSTONE-2 and BLOCKSTONE, which were both recently presented as late breakers at the 2019 OPTIONS X congress in Singapore.

The miniSTONE-2 study evaluated the safety, pharmacokinetics and efficacy of single-dose, oral suspension Xofluza compared with oseltamivir in otherwise healthy children aged one to less than 12 years of age with influenza. The median time to alleviation of signs and symptoms in influenza-infected participants was 138 hours (95% CI: 117, 163) and 150 hours (95% CI: 115, 166) for those who received Xofluza or oseltamivir, respectively. Xofluza was well tolerated, with no safety signals identified.

BLOCKSTONE evaluated Xofluza compared with placebo as a preventive treatment for household members (adults and children) who were living with someone who had been diagnosed with influenza. The proportion of household members who became symptomatically ill following infection with influenza was significantly lower in those treated preventively with Xofluza compared to those treated with placebo (proportion of subjects with influenza virus infection, fever and other flu symptoms in the 10-day observation period: 2% versus 14%, p<0.0001). Xofluza was well tolerated, with no safety signals identified.

Xofluza is the first one-dose, oral prescription medicine for the flu, and works differently from over-the-counter medicines by attacking the flu virus at its source. In October 2018, Xofluza was first approved by the FDA to treat the flu in people 12 years of age and older who have had flu symptoms for no more than 48 hours and who are otherwise healthy. In October 2019, Xofluza became the only antiviral medicine approved by the FDA to specifically treat patients at high risk of developing serious complications from flu. What should readers take away from your report?

Response: According to the CDC, the 2019-2020 influenza season is one of the worst influenza seasons for children in the past decade and there is a critical need for additional treatment options that work in different ways to attack influenza. This milestone brings us closer to potentially providing single-dose Xofluza to children with influenza in a convenient, strawberry-flavored granule oral suspension formulation. We also look forward to working with the FDA to expand the Xofluza label as a preventive treatment following exposure to influenza. The FDA is expected to make a decision on these approvals by November 23, 2020. What recommendations do you have for future research as a result of this work?

Response: Although some of the symptoms of COVID-19 and influenza can look similar, the two illnesses are caused by completely different viruses. Xofluza is specifically designed to treat influenza viruses only and has not been proven to be effective to treat human coronaviruses such as COVID-19. For more information, please visit

FDA has accepted Genentech’s NDA and two sNDAs for its flu drug Xofluza®



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Last Updated on April 7, 2020 by Marie Benz MD FAAD