Duke experts explain importance of newly approved influenza drug

Courtesy of Wikimedia Commons
Courtesy of Wikimedia Commons

A new flu drug hopes to help curb the coughs that fill classrooms in the winter. 

The Food and Drug Administration recently approved a new drug—Xofluza—that can help combat the influenza virus and shorten the amount of time people are infected. The flu treatment is the first one to be FDA-approved in nearly two decades. 

“It’s a drug that is a small molecule that interferes with a particular enzyme necessary for the influenza viruses to replicate,” explained Garnett Kelsoe, James B. Duke professor of immunology. 

Once a person contracts the flu, the virus survives in the body by hijacking the infected cell’s machinery to replicate the virus’ own genetic information. Xofluza stops the flu's enzyme that fuels viral replication.   

When used in combination with a flu vaccine, an infected individual will be less sick for a shorter period of time, Kelsoe said. Xofluza will come in the form of a single-dose oral prescription drug, intended for patients more than 12 years old who have exhibited flu symptoms for no more than two days.

Xofluza was developed by Roche and Japan's Shionogi. Currently, the pill costs $150 and will be sold by Genentech, a daughter company of Roche. In the FDA trials, Xofluza was found to be effective against both strains of influenza and was comparable to Tamiflu, also sold by Roche. 

The flu shot has to be re-administered every year due to the flu's tendency to mutate. 

“Flu vaccines aren’t very good,” Kelsoe said. 

As more people are vaccinated and the population becomes immune, the flu mutates to survive. 

"[This creates an] evolutionary race between the virus and the selected population each year,” Kelsoe said. “That’s why the National Institutes of Health is making a big push towards a generation of vaccines that are not seasonally specific but would be specific for the flu viruses that arise over a multi-year period.” 

Traditionally, after the end of flu season, vaccine makers predict which strain will have survived the past season and be dominant in the coming year. They do this by growing the virus in chicken eggs and looking for mutations.

However, many of these mutations are chicken-specific, and the molecular structure of the virus changes in ways it would not inside a human. This could result in the flu shot protecting you against a virus that doesn’t exist outside of chicken eggs, Kelsoe said. 

Xofluza does not replace a flu vaccine, and the Centers for Disease Control and Prevention still recommended getting flu shots before the end of October. 

Any Duke students who have still not gotten their flu shot can go to Student Health for a walk-in or schedule an appointment for the vaccine. John Vaughn, director of Student Health Services, said that Xofluza will not have any implications for Duke students yet because it is so new. 

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Maria Morrison

Maria Morrison is a Trinity senior and a digital strategy director for The Chronicle's 117th volume. She was previously managing editor for Volume 116.


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