Genentech's Xofluza Reduces Flu Threat by 86% Following Exposure, Data Shows


Just in time for flu season, Genentech, a Roche company, announced some good news that will make many people looking to avoid the flu happy. In a late-stage study, Genentech’s flu drug Xofluza showed significant efficacy as a preventative treatment.

South San Francisco-based Genentech said Phase III data from the BLOCKSTONE study showed that an individual treated with Xofluza after being exposed to the flu by an infected household member, reduced the risk of developing the flu by 86% compared to placebo. The study showed that 1.9% of people who were treated with Xofluza came down with the flu, compared to 13.6% of placebo patients. Genentech said the preventative benefit of Xofluza remained statistically significant regardless of influenza A subtype. That preventative benefit was also seen in patients who are more susceptible to the flu due to pre-existing conditions and in children under the age of 12, Genentech said.

Sandra Horning, Genentech’s outgoing chief medical officer and head of global product development, touted the importance of Xofluza’s ability to limit the spread of the flu bug. By limiting the spread, Horning said it avoids creating a widespread outbreak in communities.

“We are encouraged by the BLOCKSTONE study, 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,” said Horning, who will retire from the company at the end of the year.

Pointing at the late-stage MINISTONE-2 data regarding children under the age of 12, Horning noted that annually, about 33% of children develop the flu and because their immune systems are not as robust as adults, they are more prone to developing complications.

The flu represents a serious health threat each year. Globally, there are about 650,000 deaths from the flu worldwide and millions of people are hospitalized due to the illness. According to the U.S. Centers for Disease Control and Prevention, those people who are considered at high risk of serious flu complications include people over the age of 65, as well as people who have pre-existing conditions such as asthma, diabetes, heart disease or chronic lung disease.

Full results of the BLOCKSTONE study were presented as a late-breaking abstract during the OPTIONS X 2019 congress in Singapore on Sept. 1. Data from the BLOCKSTONE study also showed that even when fewer criteria were applied (proportion of participants with the flu, with fever or one or more respiratory symptoms), there was still a significant 76% reduction in the risk of household members developing the flu with Xofluza versus placebo.

Last year, the U.S. Food and Drug Administration approved Xofluza (baloxavir marboxil) for the treatment of acute, uncomplicated influenza, or flu, in people 12 years of age and older. The new medication has a novel mechanism of action that, Roche said, inhibits polymerase acidic endonuclease, an enzyme that is essential for the flu virus to replicate. When Xofluza was approved, it was the first new flu treatment approved by the regulatory agency in two decades. Xofluza is under review by the FDA as a one-dose oral treatment for people at high risk of complications from the flu. Genentech expects the FDA to make a decision regarding this New Drug Application by Nov. 4.

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