Yale Daily News

As flu season begins in full swing, the U.S. Food and Drug Administration approved a new antiviral medication to treat influenza symptoms on Wednesday.

This drug, sold under the brand name Xofluza, attacks the flu virus through a mechanism unlike any other antiviral flu medicine on the market, and is the first of its kind to win the FDA’s approval in nearly 20 years. Genentech, a San Francisco–based biotechnology company, will manufacture the drug, which will become available to patients with a prescription in the coming weeks.

“With XOFLUZA, patients now have a convenient treatment option that reduces flu symptoms by more than a day with a single oral dose,” wrote Heather Gloe, Genentech’s senior manager of corporate relations, in an email to the News.

It is unclear if Yale Health will offer Xofluza to flu patients after the drug becomes available. Director of Yale Health Paul Genecin redirected the News’ inquiries to a Yale spokesperson, who did not respond to requests for comment.

Xofluza is intended for patients 12 and older diagnosed with acute uncomplicated flu who are within two days of symptom onset. Untreated, acute uncomplicated flu typically resolves after three to seven days for most patients, although certain symptoms, like coughs, can last for more than two weeks, according to the Centers for Disease Control and Prevention.

Xofluza was granted priority review — an expedited evaluation process for drugs that the FDA believes could significantly improve the safety or effectiveness of treating, diagnosing or preventing a serious condition, according to Alison Hunt, a press officer for the FDA.

“A Priority Review designation means FDA’s goal is to take action on an application for an New Molecular Entity within eight months compared to ten months under standard review. Because thousands of Americans will get the flu each year, the FDA reviewed and approved Xofluza within six months so that it would be available during the 2018 flu season,” Hunt explained in an email to the News.

Two clinical trials showed that the single-dose pill reduces the intensity and duration of flu symptoms. The most common adverse side effects associated with Xofluza use were diarrhea and bronchitis, which occurred in 3 percent and 2 percent, respectively, of the 710 patients given the drug during the trials.

The flu virus exists as four different strains, though only two of these strains, “A” and “B,” cause flu epidemics, according to the CDC. Xofluza is unique because it specifically inhibits a protein essential for virus replication that is found within both A and B strains of the flu.

Other flu antivirals on the market, like Tamiflu, can be prescribed to treat flu symptoms. But because the flu virus often mutates during replication, current strains of the virus have developed resistance to the attack mechanisms of older classes of flu antiviral medications.

“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,” said FDA Commissioner Scott Gottlieb in a press release.

Last year saw a severe flu season, with over 49 million flu cases in the United States between 2017 and 2018, according to the CDC. The flu vaccine only reduced risk of flu-related doctor visits by 40 percent last season, while in previous years, the vaccine was between 50 and 60 percent effective at reducing this risk.

Xofluza is intended for patients who have already developed the flu and is not a replacement for an annual flu vaccine, which is the safest and most effective way to prevent the illness and its potential complications, according to Gottlieb.

All Yale faculty, staff and students are eligible to receive a free flu shot at Yale Health, according to their website. This season, Yale Health has scheduled nine flu vaccine clinics from late October to early December at several sites across Yale’s campuses.

The drug was first synthesized by the Japanese pharmaceutical company Shionogi.

Madison Mahoney | lorenzo.arvanitis@yale.edu

Marisa Peryer | marisa.peryer@yale.edu