Phase III BLOCKSTONE study of Xofluza meets primary endpoint in influenza.

Genentech/Roche announced that the Phase III BLOCKSTONE study, conducted by Shionogi & Co., Ltd., met its primary endpoint showing that people exposed to a household member with influenza (flu) and treated preventatively with Xofluza (baloxavir marboxil) were significantly less likely to develop the disease compared to those treated with placebo (1.9% versus 13.6%, p<0.0001).

Xofluza showed a significant prophylactic effect on influenza infection after a single oral dose in people exposed to an infected family member. The proportion of household members who became symptomatically ill following infection with flu was significantly lower in those treated preventively with Xofluza compared to those treated with placebo (proportion of subjects with influenza virus infection, fever and other influenza symptoms in the 10-day observation period: 1.9% versus 13.6%, p<0.0001). The incidence of adverse events was 22.2% and 20.5% in Xofluza and placebo respectively. No serious adverse events were reported for Xofluza. Secondary objectives were clinical efficacy, pharmacokinetics and safety and tolerability. Full results from the BLOCKSTONE study will be presented at an upcoming medical meeting.

Comment: Xofluza is currently approved in Japan for the treatment of influenza types A and B in children, adolescents and adults, and in the U.S. for the treatment of acute, uncomplicated influenza in people 12 years of age and older. In addition, the FDA recently accepted a supplemental New Drug Application (sNDA) for Xofluza as a one-dose oral treatment for people at high risk of complications from the flu, which includes adults 65 years of age or older, or those who have conditions such as asthma, chronic lung disease, morbid obesity or heart disease – for these people the flu can be particularly serious or deadly. The FDA is expected to decide on whether to approve this additional indication by November 4, 2019.