Genentech's Xofluza Effective at Preventing Flu After Household Exposure in Clinical Trial

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Genentech, a Roche company, announced the results from its Phase III BLOCKSTONE trial, conducted by Shionogi & Co. The BLOCKSTONE trial evaluated a single dose of Xofluza compared with placebo in household members, both adults and children, in Japan who were sharing a household with someone with the flu. The infection was confirmed using a rapid influenza diagnostic assay. It was conducted by Shionogi during the 2018-2019 flu season in Japan.

The participants in the trial were randomized to either receive a single dose of Xofluza, adjusted by body weight, or a placebo. The primary endpoint was the proportion of people who tested positive for the flu virus and had a fever and one or more respiratory symptoms between day one and 10.

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Xofluza showed a significant preventive effect after a single oral dose. Only about 1.9% of patients who received Xofluza showed signs of the flu, compared to 13.6% of the placebo group. In terms of side effects, 22.2% of the Xofluza cohort showed side effects compared to 20.5% of the placebo group. No serious adverse events were reported.

Xofluza is a first-in-class, one-dose oral drug. Its proposed mechanism has shown efficacy in a broad range of flu viruses, including in vitro activity against oseltamivir-resistant strains and avian strains in non-clinical studies. It’s the first in a new class of antiviral drugs that inhibit the cap-dependent endonuclease protein. This protein is vital for viral replication.

The drug was discovered by Shionogi and is being developed and commercialized globally by Roche, which includes Genentech in the U.S., and Shionogi. Roche holds worldwide rights to the drug excluding Japan and Taiwan, where Shionogi holds the rights.

Xofluza is approved in the U.S. to treat the flu in people 12 years old or older who have had flu symptoms for no more than 48 hours.

“This positive Phase III study adds to robust existing clinical data for Xofluza, and is the first to show that a single treatment with Xofluza reduced the likelihood that people living with an infected household member would develop the flu,” stated Sandra Horning, chief medical officer and Head of Global Product Development for Genentech. “Preventing otherwise healthy people from developing the flu virus will reduce the overall societal burden of disease, and we look forward to sharing these data with health authorities around the world.”

Yesterday, Genentech announced positive topline data from two Phase III trials evaluating Xolair (omalizumab) for adults with chronic rhinosinusitis with nasal polyps. The POLYP 1 and 2 Phase III trials both met co-primary endpoints and key secondary endpoints.

“The results from these pivotal studies provided further support that IgE plays a role in inflammatory and respiratory conditions, and showed that Xolair reduced the size of nasal polyps and associated symptoms that impact these patients’ quality of life,” Horning stated. “We plan to discuss these results with the FDA with the goal of bringing this new treatment option as soon as possible to people who do not experience relief with the current standard of care.”

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