Roche’s Xofluza limits spread of flu virus, says new study

Roche’s new influenza drug Xofluza can dramatically prevent the spread of the virus when used as a preventive therapy, according to new phase 3 data.

Xofluza (baloxavir marboxil) is already approved to treat people infected with flu, but the new results make a case to extend its use to include healthy people at risk of contracting the virus such as household members.

The BLOCKSTONE study found that giving a single oral dose of Xofluza after exposure to someone with flu reduced the risk of developing the illness by 86% compared to placebo, and with the protection seen regardless of the flu strain involved.

All told, 1.9% of Xofluza-treated household members contracted flu after exposure, compared to 13.6% of the control group. The protective effect also came into play in people at greater risk of contracting the virus, such as young children, and Roche says its drug had a “placebo-like” side-effect profile.

Limiting the spread of the virus in this way could be an important step in curbing flu outbreaks and preventing the spread in the wider community, according to Roche’s chief medical officer Sandra Horning.

The BLOCKSTONE trial is “the first to show that Xofluza is an effective preventive treatment following exposure to the flu and we look forward to sharing these data with health authorities,” she added.

The prevention results come after Xofluza was shown to be effective in children in the MINISTONE-2 study reported in July.

Xofluza is a cap-endonuclease inhibitor that interrupts a mechanism used by the virus to hijack the messenger RNA transcription system in cells, switching off virus production, and became the first new-mechanism treatment for flu in more than 20 years when it was cleared by the FDA last year.

Roche is hoping the new drug can breathe new life into its flu franchise, represented by older neuraminidase inhibitor Tamiflu (oseltamivir). That was a $3 billion brand at its peak, but has slumped since patent expiry and brought in $333 million in sales last year.

Xofluza needs all the help it can get at the moment, with sales in the first half just $6 million as the new product contended in the marketplace with low-cost Tamiflu generics.

In its favour is that it can be delivered as a single dose, while Tamiflu and generic oseltamivir has to be taken twice-daily for at least five days.

Xofluza is also effective in lab studies against oseltamivir-resistant flu strains, and it outperformed the older drug in the CAPSTONE-2 trial in people at high risk of flu complications. An FDA verdict on the latter is due by 4 November.

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