FDA Approves Roche’s Established Antiviral For Children Aged Five Or Older

On August 11, Roche announced that the United States Food and Drug Administration (FDA) approved a supplemental New Drug Application (sNDA) for Xofluza® (baloxavir marboxil). Xofluza is an antiviral initially approved for the treatment of influenza type A and B in children aged twelve or above. However, the sNDA approves the use of the antiviral for children aged five or older who have come into contact with someone infected with influenza.

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The Importance of Antivirals for Children

Influenza is a severe illness for children. During the 2018-2019 influenza season alone, over one hundred children aged five to seventeen died from the sickness. The immune system is relatively weaker early in life, only maturing around age seven-eight. As a result, using antivirals is paramount to bolstering children’s ability to fight off infections. 

On the spread of influenza among children, Dr. Pedro Piedra, miniSTONE-2 Study Investigator and Professor of Molecular Virology, Microbiology, and Pediatrics at Baylor College of Medicine, said, “Historically, school-aged children have played a significant role in the community transmission of influenza. The annual influenza vaccine continues to be the most important first step to prevent illness in children, though there can still be breakthrough cases where antiviral treatment is needed.”

Aside from Xofluza, there are only three other FDA-approved antivirals that the Center for Disease Control and Prevention (CDC) recommends for use in children fighting influenza. Gilead Sciences’ Tamiflu (oseltamivir phosphate) is an oral antiviral for children two or older. GSK’s Relenza (zanamivir) treats children seven or older. However, children suffering from underlying respiratory diseases such as asthma should not take it. In addition, a special inhaler is the administration method. Rapivab (peramivir) treats children aged two years or older. However, administration requires an intravenous line.

Similar to Tamiflu, Xofluza is an oral antiviral. Initially, it received approval in 2019 for use in children twelve or older who have had influenza symptoms for no more than 48 hours and are otherwise healthy or at high risk of developing influenza-related complications. However, the FDA approved its use in children aged five or older based on data gathered from the miniSTONE-2 and BLOCKSTONE studies. 

Two Studies Support Amending the Approval

miniSTONE-2 is a Phase III, multicentre, randomized, double-blind study evaluating the safety, pharmacokinetics and efficacy of Xofluza. The study centered around observing a single dose of Xofluza compared to oseltamivir in otherwise healthy children in two different age groups within 48 hours of displaying symptoms of influenza. The two age groups were those no younger than five and those no younger than twelve. Overall, Xofluza demonstrated a medium symptom alleviation time of 138 hours, while oseltamivir showed a time of 150 hours. Xofluza also proved itself tolerable in both sets of patients.

Another Phase III, double-blind, multicentre, randomized, placebo-controlled study was BLOCKSTONE. However, it analyzed post-exposure prophylaxis of a single dose of Xofluza compared to placebo in household members, including children and adults, of someone who tested positive for influenza. Xofluza demonstrated that it significantly reduced the risk of those who took it from contracting the illness; around 90% of participants who took the antiviral did not develop influenza.

Due to the results of this study, the FDA approved Xofluza’s use in children aged five or older.

The approval of the use of Xofluza in children aged five or older marks a vital step in safeguarding vulnerable children. Now, there is yet another tool in parents’ and healthcare providers’ arsenal to use to give young children a better chance of fighting off influenza. 

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Author

Max Heirich