Genentech Flu Drug Scores Another Late-Stage Win

With flu season fast approaching, Genentech has some good news for people who are at high risk of complications from the illness. The South San Francisco-based company said its late-stage therapy for that patient population was faster at helping those patients recover from the effects of the illness than placebo.

Genentech’s baloxavir marboxil, an investigational oral, single-dose antiviral, is the first flu medicine with a novel proposed mechanism of action in nearly 20 years and to demonstrate significant efficacy in high-risk populations, Genentech said. Although very common, 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.

Baloxavir marboxil was discovered and developed by Shionogi & Co., Ltd., and is sold in Japan under the trade name Xofluza. Roche holds worldwide rights to the drug outside of Japan and Taiwan.

In the Phase III trial, baloxavir marboxil reduced the time that the virus continued to be released, called viral shedding, and also reduced viral levels in the body, according to the announcement. Additionally, baloxavir marboxil significantly reduced the incidence of influenza-related complications compared to placebo, Genentech said. The Roche subsidiary also said that baloxavir marboxil was well tolerated and no safety signals were identified.  Genentech said it will release full results from the CAPSTONE-2 trial at an upcoming medical meeting.

“Baloxavir marboxil is the first antiviral to show a clinically meaningful benefit in people who are most susceptible to complications from the flu, including older people and those living with certain medical conditions,” Sandra Horning, Genentech’s chief medical officer and head of Global Product Development said in a statement. “We plan to submit the results of this second positive Phase III study for baloxavir marboxil to healthcare authorities, and look forward to discussing next steps since there are no current antiviral medicines approved to specifically treat this high-risk population.”

Genentech noted that in the Phase III CAPSTONE-1 study, Baloxavir marboxil demonstrated a clinically significant benefit over placebo in healthy people. Based off that study, the U.S. Food and Drug Administration accepted a New Drug Application and granted Priority Review to baloxavir marboxil as a single-dose, oral treatment for acute, uncomplicated influenza in people 12 years and older. The regulatory agency is expected to make a decision on that NDA by Christmas Eve of this year. If approved, baloxavir marboxil would be the first single-dose oral antiviral, and the first medicine with a novel proposed mechanism of action to treat the flu in nearly 20 years, Genentech said.

Baloxavir marboxil will also be studied in a Phase III program including pediatric and severely ill hospitalized populations with influenza.