It's Flu Season! Genentech's Investigational Medicine Continues to Show Efficacy


New late-stage data released by South San Francisco-based Genentech shows treatment with baloxavir marboxil significantly reduced the time to the improvement of influenza symptoms versus placebo in patients who are at high risk of serious complications from the flu.

The Phase III CAPSTONE-2 study is the first late-stage trial to show a clinically meaningful benefit in people who are at high risk for the flu, said Sandra Horning, Genentech’s chief medical officer and head of Global Product Development.

“This study adds to the growing body of evidence supporting baloxavir marboxil as a potential first-in-class antiviral flu treatment, and we plan to discuss these data with health authorities around the world,” Horning said in a statement.

The CAPSTONE-2 study showed that taking baloxavir marboxil reduced the time for symptom improvement in influenza type A/H3N2 and type B to 75.4 hours and 74.6 hours, respectively. Results for the overall patient population of the study showed numerically shorter time to the improvement of influenza symptoms of baloxavir marboxil versus oseltamivir with a median time to the improvement of symptoms of 73.2 hours compared to 81 hours, Genentech said.

Baloxavir marboxil is a single-dose, investigational oral medicine. Genentech said the treatment represents the first of a “new class of antivirals with a novel proposed mechanism of action that differs from other currently available treatments.” In a previous Phase III study, known as CAPSTONE-1, baloxavir marboxil demonstrated a clinically significant benefit over placebo in otherwise healthy people with influenza. Baloxavir marboxil reduced the time that the virus continued to be released, called viral shedding, and also reduced viral levels in the body. Based on those Phase III results, 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 FDA is expected to make a decision on approval by Dec. 24. If approved, Genentech said baloxavir marboxil will 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.

Baloxavir marboxil is sold in Japan under the trade name Xofluza. It was approved by Japanese regulatory authorities in February. Roche holds worldwide rights to baloxavir marboxil excluding Japan and Taiwan. Those rights will be retained exclusively by Shionogi & Co., Genentech said.

Data from the Phase III trial will be presented this weekend at IDWeek 2018 in San Francisco. Baloxavir marboxil will also be further studied in a Phase III development program including pediatric populations and severely ill hospitalized people with influenza.

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. 

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