FDA approves Xofluza for influenza prevention following contact with an infected person

Nov. 25, 2020

Roche announced that the U.S. Food and Drug Administration (FDA) has approved a supplemental New Drug Application (sNDA) for Xofluza (baloxavir marboxil) as a treatment to prevent influenza in people 12 years of age and older following contact with someone with influenza (known as post-exposure prophylaxis). 

“With today’s approval, Xofluza is now available as the first single-dose, post-exposure preventive treatment for influenza,” said Levi Garraway, M.D., Ph.D., Roche’s Chief Medical Officer and Head of Global Product Development. “We’re hopeful that reducing the burden of influenza may help to mitigate the strain on our healthcare system amid the COVID-19 pandemic.” 

Post-exposure prophylaxis with single-dose Xofluza was evaluated in the phase III BLOCKSTONE study, which was recently published in The New England Journal of Medicine. BLOCKSTONE evaluated Xofluza compared with placebo as a preventive treatment for household members (adults and children) who were living with someone with influenza. Xofluza showed a statistically significant prophylactic effect on influenza after a single oral dose in people exposed to an infected household contact. The proportion of household members 12 years of age and older who developed influenza was one percent in participants treated with Xofluza and 13 percent in the placebo-treated group. Xofluza was well tolerated in this study and no new safety signals were identified. 

“The flu is a serious illness that burdens households and sickens millions across the US every year,” said Serese Marotta, Chief Operating Officer at Families Fighting Flu. “As we are about to enter a flu season within a global COVID-19 pandemic, we welcome Xofluza as a single-dose flu medicine to be used preventively after exposure to flu.” 

The most frequently reported adverse events (occurring in at least one percent of adult and adolescent influenza patients treated with Xofluza) included diarrhoea (three percent), bronchitis (three percent), nausea (two percent), sinusitis (two percent), and headache (one percent). 

Additionally, Roche is determining a path forward with the FDA for a potential indication for Xofluza as a treatment for acute uncomplicated influenza in otherwise healthy children (one to 12 years of age) and for the prevention of influenza in the same age group who have been exposed to influenza. Xofluza is currently not approved for use in this population. 

Xofluza is already FDA-approved to treat acute uncomplicated influenza in people 12 years of age and older who have had influenza symptoms for no more than 48 hours and who are otherwise healthy or at high risk of developing influenza-related complications. 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 is not effective against SARS-CoV-2, the coronavirus causing COVID-19. 

BLOCKSTONE is a phase III, double-blind, multicenter, randomized, placebo-controlled, post-exposure prophylaxis study that evaluated a single dose of Xofluza (baloxavir marboxil) compared with placebo in household members (adults and children) who were living with someone with influenza confirmed by a rapid influenza diagnostic test (the ‘index patient’). The study was conducted by Shionogi & Co., Ltd. in Japan during the 2018-2019 influenza season. 

Those diagnosed with influenza were required to have onset of symptoms for less than 48 hours and participants were required to have lived with those diagnosed for more than 48 hours. The participants were randomized to receive a single dose of Xofluza (dose according to body weight) or placebo as a preventive measure against developing influenza. 

Xofluza was discovered by Shionogi & Co., Ltd. and is being further developed and commercialized globally in collaboration with the Roche Group (which includes Genentech in the US) and Shionogi & Co., Ltd. Under the terms of this agreement, Roche holds worldwide rights to Xofluza excluding Japan and Taiwan, which will be retained exclusively by Shionogi & Co., Ltd. 

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