New flu drug Xofluza approved - FDA emphasizes importance of flu shots

By Dr. Ananya Mandal, MDOct 25 2018

A new drug that works against flu has been developed and has been approved by the Food and Drug Administration (FDA) yesterday (24th October 2018). Until now the only drug available for flu is oseltamivir (Tamiflu) which is to be administered by two pills per day for five days after symptoms appear.

The new drug is called baloxavir marboxil and is branded as Xofluza. It is a single dose treatment for use in persons over 12 years of age. Xofluza is to be taken within the first two days after the symptoms of flu appear. Flu symptoms include runny nose, body aches and fever.

Each of the pills would cost around $150 according to a spokeswoman for manufacturer Genentech. Coupons would be available that would allow the insured to buy the pill at $30 and the uninsured to buy them at about $90.

Earlier this month the Centers for Disease Control and Prevention (CDC) had said that flu season has started for this year and last year many succumbed to the illness (around 80,000).

CDC continues to recommend routine vaccination against flu each year after the age of six months to remain protected against the infection. It says that the new drug is not a cure for all and moreover, it is not yet approved for children below 12 years who are a vulnerable age group for contracting the flu.

CDC information website emphasize on the fact that flu virus is capable of rapid mutations and can soon become resistant to any drugs effective against it. It has already developed resistance to several older drugs that were effective against it.

“This is the first new antiviral flu treatment with a novel mechanism of action approved by the FDA in nearly 20 years,” FDA chief Scott Gottlieb said in a statement. “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.”

The new drug Xofluza works against the flu virus by blocking an enzyme which is essential for the virus to replicate itself and multiply. This means that the earlier resistant strains of the virus may be susceptible to this new drug. This new drug is further effective against both A and B strains especially the bird flu strains such as A strains of H5N1 and H7N9. The new drug was developed by Shionogi, a Japanese company.

Dr. Debra Birnkrant, the FDA’s director of antiviral products explained that Xofluza does not clear a bout of flu rapidly but may reduce the duration of the illness and its severity. “While there are several FDA-approved antiviral drugs to treat flu, they’re not a substitute for yearly vaccination,” Gottlieb warned.

There are two reported clinical trials, the agency said, that led to the approval. The trials involved 1,832 patients. One trial compared Xofluza against placebo while the other compared it against Tamiflu.

No superiority was seen when compared against Tamiflu but when compared to placebo, the recovery was quicker. Side effects noted with Xofluza use were diarrhoea and bronchitis according to the FDA report. One of the trial results from the CAPSTONE-1 study was published in the New England Journal of Medicine.

This approval received a “priority review” status in June this year and was expedited. Further studies are being conducted to see if the drug is effective and safe in children.