Baloxavir--The New, Single Oral-Dose Antiviral for Influenza

Arefa Cassoobhoy, MD, MPH


November 29, 2018

Hello. I'm Dr Arefa Cassoobhoy, a primary care internist, Medscape advisor, and senior medical director for WebMD. Welcome to Medscape Morning Report, our 1-minute news story for primary care.

For the first time in 20 years, we have a new antiviral drug to battle influenza A and B. It's different from other antivirals, such as oseltamivir. The new drug, baloxavir (with the brand name Xofluza), has a novel mechanism of action: It's a selective inhibitor of the enzyme influenza cap-dependent endonuclease; it blocks viral replication by preventing mRNA synthesis.

In clinical trials, a single oral dose of baloxavir significantly reduced the duration of flu symptoms and fever compared with placebo. The patients' symptoms resolved 23-28 hours sooner. Its efficacy in symptom reduction is similar to that of oseltamivir. Like the older drug, it must be given within 48 hours of symptom onset and is more effective if given within 24 hours of flu symptoms.

Baloxavir seems well tolerated. The most common adverse reactions were diarrhea and bronchitis.

As far as differences when compared with oseltamivir, patients with uncomplicated influenza who received baloxavir had a shorter duration of viral shedding.

As the new drug becomes available, researchers will follow to see if resistance emerges with this one-dose drug, and to see if combination therapy with baloxavir and oseltamivir may be useful for some groups of patients.

For now, baloxavir is approved for patients over age 12.

Follow Dr Cassoobhoy on Twitter at @ArefaMD


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