Xofluza Approved to Treat and Prevent Flu in Children 5 to 12 Years Old

Although vaccination is still the best way to protect against the flu, the drug may help reduce transmission of influenza.

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Xofluza 20 mg box
In October 2018, Xofluza was the first anti-flu medication to gain approval in 20 years.Courtesy of Genentech; Canva

Drugmaker Genentech announced that the U.S. Food and Drug Administration (FDA) approved its flu drug Xofluza for children ages 5 to 12.

The FDA greenlighted a supplemental New Drug Application (sNDA) for Xofluza (baloxavir marboxil) for the treatment of acute uncomplicated influenza in otherwise healthy children who have been symptomatic for no more than 48 hours, according to a?statement released last week by the company. Xofluza is the first single-dose oral influenza medicine that’s been approved for children in this age group.

Additionally, the FDA approved Xofluza to help prevent influenza in children in this age group following contact with someone with the flu.

“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,” said Levi Garraway, MD, PhD, chief medical officer and head of global product development at Genentech, in the release. “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.”

Xofluza is an important tool because it is a single dose and has been effective at decreasing the symptoms of influenza, says Amesh A. Adalja MD,?senior scholar at the Johns Hopkins Center for Health Security in Baltimore. “Having multiple antiviral options is always a good thing for any infection,” he adds.

The FDA approval is based on results from two Phase 3 studies, miniSTONE-2 and BLOCKSTONE. MiniSTONE-2 evaluated Xofluza compared with oseltamivir in otherwise healthy children and included patients age 5 to?less than 12 years with an influenza infection and displaying influenza symptoms for no more than 48 hours.

BLOCKSTONE evaluated Xofluza compared with placebo as a preventive treatment for household members (adults and children) who were living with someone with influenza.

Adverse events reported in at least 5 percent of the participants (5 to 11 years old) were vomiting (5 percent) and diarrhea (5 percent).

In Adults, Xofluza Shortens Duration of Flu by About 1 Day

In October 2018, the flu drug was approved for use in people over the age of 12, making it the first anti-flu medication to gain approval in nearly 20 years.

In the clinical trials in adults that were the basis for the drug’s fast-tracked approval, Xofluza reduced flu symptoms by a little more than a day in healthy patients over the age of 12. In clinical trials, Xofluza shortened the duration of the flu by about 24 hours if it’s given within the first 48 hours of the onset of symptoms.

That is similar to the efficacy of Tamiflu, another drug used to treat the flu, according to the?Cleveland Clinic. However, Xofluza is administered in a single dose as opposed to the 5 days of therapy that Tamiflu requires.

In November 2020, the FDA expanded its approval, adding an indication for Xofluza to treat post-exposure prevention of the flu for people 12 and older after contact with someone with the flu.

How Xofluza Works

Xofluza works via a different mechanism of action than other available anti-flu drugs, according to the drug’s fact sheet. Once the flu virus gets into your system, it reproduces over and over and then spreads throughout your body. Xofluza inhibits polymerase acidic endonuclease, the enzyme that allows the virus to reproduce, which is earlier in the disease process than other flu medications.

Early Data Indicates This Flu Season May Be More Severe

During the 2021–2022 flu season,?flu activity in the United States was lower than pre-pandemic levels despite increased reporting and testing, a trend that experts suspect may have been the result of COVID-19 precautions, according to a report released on July 22, 2022?from the Centers for Disease Control and Prevention (CDC).

Using data available from early October 2021 through mid-June 2022, the agency estimated that influenza virus infection resulted in 8 to 13 million symptomatic illnesses, 3.7 to 6.1 million medical visits, 82,000 to 170,000 hospitalizations, and 5,000 to 14,000 deaths.

That’s significantly less severe than many earlier flu seasons. In 2018–2019, there were 29 million cases of the flu, 13 million flu-related doctor visits, 380,000 flu-related hospitalizations, and 28,000 flu deaths, including more than 100 deaths of children between the ages of 5 and 17 years, according to the?CDC.

Heath experts often look to the Southern Hemisphere as one indicator of what the flu season will be in Northern Hemisphere (which includes the United States). This year Australia reports the number of flu cases so far has exceeded the five-year average, according to an NBC News report.

Getting a Flu Shot Is the Best Way to Protect Yourself From the Flu

The flu vaccine is the best way to help protect against the flu, which is why the CDC recommends that everyone 6 months and older should get a flu shot (with rare exceptions) every year.