A powerful new drug for influenza that's fast-acting and can be taken as a single dose may be making its way to the United States soon.

The drug, called baloxavir marboxil, is getting priority review from the U.S. Food and Drug Administration.

If approved, it is set to be the very first oral and single-dose antiviral. It will also be the first flu medicine that features a brand-new mechanism in almost 20 years.

Baloxavir Marboxil

Baloxavir marboxil targets the flu virus, including oseltamivir-resistant strains and avian strains, according to a press release from drug developer Genentech.

As an endonuclease inhibitor, this new drug works in a different way than other influenza drugs available. This makes it the first new type of influenza drug to be introduced to the market in more than two decades. Endonuclease inhibitors keep the flu virus from multiplying and infecting other cells.

The two other classes of drugs for influenza include neuraminidase inhibitors and adamantane drugs, the latter of which is not recommended due to the virus' ability to develop resistance to it.

"The severity of the recent flu season underscores the need for new options beyond currently available treatments, and if approved, baloxavir marboxil would be the first flu medicine with a novel proposed mechanism of action in nearly 20 years," Sandra Horning of the Global Product Development says in a statement.

Being effective in just a single dose is another advantage of baloxavir as there are no other flu drugs on the market that can be taken in just one dosage.

The Reception For Baloxavir

So far, it's been shown to be very strong as well as quick in addressing the flu symptoms in patients.

"Baloxavir marboxil has been shown in clinical trials to decrease the duration of symptoms with one dose, and demonstrated a significant reduction in viral shedding in just one day," Horning continues, adding that the company is looking forward to their work alongside the FDA as they undergo the entire review process.

While the drug is still awaiting approval in the United States, it's already available in the Japanese market. Baloxavir marboxil is sold under the brand name Xofluza by Shionogi & Co.

Shionogi has rights in Japan and Taiwan, but Roche acquired most of the global rights. Genentech, which is developing baloxavir for the United States, is a Roche company.

The FDA will reportedly make a decision on the approval by Dec. 24, 2018.