FDA Approves Baloxavir Marboxil to Treat, Prevent Flu in Younger At-Risk Children

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The newest indications for the novel oral antiviral drug will make it available as an acute treatment and prophylaxis for children this flu season.

The US Food and Drug Administration (FDA) has approved Genentech’s baloxavir marboxil (Xofluza) for the treatment of acute, uncomplicated influenza in healthy children aged 5 to ≤12 years old who have been symptomatic with the flu for ≤48 hours.

The supplemental New Drug Application (sNDA) for the novel antiviral therapy also indicates its use for post-exposure prevention of flu in children from the same age group who have made contact with a person infected with influenza. Baloxavir marboxil is now the first single-dose oral medication approved for treating flu in children of this age group.

This second FDA approval is based on results from the phase 3 miniSTONE-2 and BLOCKSTONE trials—the former showing baloxavir marboxil’s benefit in treating influenza in children aged 5 to ≤12 years old after 48 hours versus oseltamivir, and the latter showing its benefit as a prophylactic treatment for household members living with someone infected with influenza versus placebo.

Investigators observed common adverse events such as vomiting and diarrhea in approximately 5% of the pediatric populations treated with baloxavir marboxil in each study.

MiniSTONE-2 investigator Pedro Piedra, MD, professor of molecular virology, microbiology and pediatrics at Baylor College of Medicine, emphasized the historic and significant role of school-aged children in the community-level transmission of influenza every flu season. Per the Centers for Disease Control and Prevention (CDC), US pediatric flu cases prior to prominent public masking due to COVID-19 were upward of 6 million cases annually.

“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,” Piedra said in a statement. “Today’s FDA approval provides children with a single-dose antiviral option, Xofluza, to treat influenza."

Levi Garraway, MD, PhD, chief medical officer and head of Global Product Development at Genentech, praised the added indications for baloxavir marboxil to cover flu treatment and prevention of nearly every at-risk pediatric patient.

“Despite the ongoing COVID-19 pandemic, influenza continues to be a threat to public health, and effective influenza antivirals remain critical to alleviating the burden on healthcare systems,” Garraway said. “Xofluza has proven to be an important tool in fighting and preventing influenza in adults as well as adolescents, and we are pleased to now offer households and younger children our single-dose oral treatment.”