Roche’s single-dose flu drug Xofluza, Tamiflu’s successor, wins speedy FDA approval

Roche's flu drug Xofluza has won FDA approval and will set out on a task to recover sales lost to Tamiflu generics. (Roche)

Perhaps hoping to add a powerful weapon against influenza before this flu season gains full steam, the FDA has waved through Roche’s antiviral Xofluza two months ahead of a decision deadline.

Xofluza, also known as baloxavir marboxil, is now “the first new antiviral flu treatment with a novel mechanism of action approved by the FDA in nearly 20 years,” FDA Commissioner Scott Gottlieb, M.D., said in a statement. For Roche’s Genentech, which gained ex-Japan/Taiwan rights from developer Shionogi in 2016, Xofluza is tasked with salvaging some big sales that generics to its popular flu drug Tamiflu have eaten up.

Though the FDA nod came two months ahead of schedule, Genentech said it would launch the drug across the U.S. in the coming weeks. It has set the drug’s wholesale acquisition cost at $150 and is also offering coupons that lower the drug’s price to as low as $30 for patients with commercial insurance, a company spokesperson told FiercePharma.

Xofluza works by inhibiting an enzyme called polymerase acidic endonuclease, stopping viral replication early. A phase 3 trial in 1,436 people showed Xofluza, with a single dosage, could alleviate flu symptoms as fast as Tamiflu, which usually requires twice daily dosing for five days. It has also demonstrated the ability to stop virus release from the body significantly faster than Tamiflu, meaning it’s more potent at stopping the virus from spreading to other people.

Because it doesn’t significantly cut the time to symptom improvements compared with Tamiflu, the one-dose convenience will likely be the company’s card to play against cheap Tamiflu generics. “If patients see their doctors within 48 hours of symptom onset, one dose of Xofluza can significantly reduce the duration of flu symptoms,” Sandra Horning, Genentech’s chief medical officer and head of global product development, said in a statement.

The current FDA nod limits the drug’s use to those aged 12 or above with uncomplicated flu, and only in the first two days after flu symptoms emerge. But Roche is pursuing expansion into people at high risk of serious complications, including older people and those living with chronic lung disease, heart disease and diabetes, among others.

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In a separate phase 3 study in this population, the drug showed a numeric advantage over Tamiflu at time to symptom relief, or 73.2 hours versus 81.0 hours, to be specific. Though that wasn’t a statistically significant improvement Roche can tout, Xofulza did post a few benefits. For example, Xofluza achieved symptom improvement much faster than Tamiflu in patients with influenza type B, where other antivirals have shown limited efficacy or inconclusive data.

The FDA’s quick decision comes as the 2018-19 flu season kicks off and also on the back of one of the deadliest seasons in decades. “Having more treatment options that work in different ways to attack the virus is important because flu viruses can become resistant to antiviral drugs,” Debra Birnkrant, director of the FDA’s Division of Antiviral Products, said.

Tamiflu has suffered from generic competition, even with the help of a strong flu season that saw Tamiflu sales jump 11% in the first quarter. Now, with Xofluza on its way to the shelf, the question is whether the follow-up drug can meet the expectation laid out by Roche’s pharmaceuticals division chief Dan O’Day as “a full replacement for Tamiflu.”

Editor's Note: This story has been updated with Xofluza's U.S. wholesale acquisition price.