New, Single-Pill Antiviral Baloxavir Marboxil Approved to Treat Influenza

By Brenda L. Mooney /alert Contributor
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A single-pill antiviral treatment for influenza has been approved by the U.S. Food and Drug Administration, according to a press release.

Xofluza (baloxavir marboxil) received approval for treatment of acute uncomplicated influenza in patients 12 years of age and older who have been symptomatic for no more than 48 hours.

“This is the first new antiviral flu treatment with a novel mechanism of action approved by the FDA in nearly 20 years. With thousands of people getting the flu every year, and many people becoming seriously ill, having safe and effective treatment alternatives is critical. This novel drug provides an important, additional treatment option,” FDA Commissioner Scott Gottlieb, MD, said in the press release.


Flu pill. Source

The drug, already available in Japan, has a different mechanism of action from the other class of approved flu antivirals, such as Tamiflu. Xofluza is a first-in-class, single-dose oral medicine with a novel proposed mechanism of action that inhibits polymerase acidic endonuclease, an enzyme essential for viral replication. The product also has demonstrated efficacy against a wide range of influenza viruses, including oseltamivir-resistant strains and avian strains (H7N9, H5N1) in non-clinical studies.

“Xofluza is the first new flu medicine with a novel proposed mechanism of action approved in nearly 20 years, and we’re excited to offer a convenient treatment option that reduces flu symptoms by more than a day with a single oral dose,” said Sandra Horning, MD, Roche’s chief medical officer and head of global product development. “If patients see their doctors within 48 hours of symptom onset, one dose of Xofluza can significantly reduce the duration of flu symptoms.”

Xofluza was approved under priority review based on results from the phase III CAPSTONE-1 study of a single-dose of Xofluza compared with placebo or oseltamivir 75 mg, twice daily for five days. Participants were otherwise healthy people with the flu.

Also considered by the FDA in the approval were results from a placebo-controlled phase II study in otherwise healthy people with the flu. Xofluza significantly reduced the duration of flu symptoms compared to placebo, and demonstrated similar efficacy compared to oseltamivir. Both studies were published recently in the New England Journal of Medicine.

“When treatment is started within 48 hours of becoming sick with flu symptoms, antiviral drugs can lessen symptoms and shorten the time patients feel sick,” explained Debra Birnkrant, MD, director of the Division of Antiviral Products in the FDA’s Center for Drug Evaluation and Research. “Having more treatment options that work in different ways to attack the virus is important because flu viruses can become resistant to antiviral drugs.”

The most common adverse reactions in patients taking Xofluza were diarrhea and bronchitis, according to the trials.