FDA approves game-changing influenza drug

Gilmore

While the newest influenza drug is novel, it faces competition from Tamiflu and generic Tamiflu, experts say.

As the first flu drug approved by FDA in more than 20 years, baloxavir marboxil (Xofluza, Shionogi & Co./ Roche/ Genentech) is novel because it is a single-dose tablet and targets a different enzyme in the replication of the virus than other antivirals, Peter Gilmore, principal at KPMG Strategy, told FormularyWatch.

Xofluza inhibits cap-dependent endonuclease in the polymerase acidic (PA) protein, an enzyme essential for viral replication, said the drug’s manufacturer, Shionogi & Co., Ltd., in a statement.

The drug, marketed in partnership with Roche and Genentech, will be available in the U.S. in the coming weeks, Shionogi said.

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FDA approved Xofluza after Shionogi demonstrated that patients treated with Xofluza had a shorter time to alleviation of symptoms than those who took placebo, the agency said.

“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, MD, in an FDA statement.

However, Gilmore expects the majority of formulary managers to encourage the use of generic oseltamavir (Tamiflu).Global sales of Tamiflu were down 33% in 2017 and the drug was not even mentioned in Roche’s 2018 nine-month results this October because of the significant impact of generic Tamiflu on the sales of the branded drug, according to Gilmore.

Generic Tamiflu was approved by FDA in 2016.

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“Patients will almost always have a higher copay for Xofluza over the generic,” Gilmore said. “Formulary managers are likely to keep generic Tamiflu as the preferred agent despite the clinical advantages of Xofluza.”

However, Xofluza has advantages over generic Tamiflu for patients with complications, Gilmore said. “Physicians have a case to use the drug over a generic, especially with the patients dealing with asthma or COPD.  Patients and physicians will have to make the choice about paying more out-of-pocket for efficacy and better convenience with fewer doses.”

Roche’s executives expect Xofluza, which will sell for a list price of $150 before any promotions/rebates, to fully replace sales of Tamiflu, according to Gilmore.

Initial projections forecast Xofluza sales to reach $655 million globally by 2024, John Santilli, president of Market Access Intelligence, told FormularyWatch.

“Xofluza side effects are also expected to be less than those experienced with Tamiflu,” Santilli added. Diarrhea and bronchitis are the most common side effects, according to Shionogi.

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