Baloxavir marboxil success in Phase III CAPSTONE-2 study to treat influenza.- Genentech/Roche + Shionogi.

Genentech, announced that the Phase III CAPSTONE-2 study assessing the safety and efficacy of baloxavir marboxil in people at high risk of complications from the flu met the study's primary objective, and showed superior efficacy in the primary endpoint of time to improvement of influenza symptoms versus placebo. The Centers for Disease Control and Prevention (CDC) defines people at high risk for serious flu complications to include adults 65 years of age or older, or those who have conditions such as asthma, chronic lung disease, diabetes or heart disease – for these people, the flu can lead to hospitalization or even death.

Baloxavir marboxil also demonstrated superior efficacy compared to placebo and oseltamivir for important secondary endpoints, including reducing the time that the virus continued to be released (viral shedding) and reducing viral levels in the body. Furthermore, baloxavir marboxil significantly reduced the incidence of influenza-related complications compared to placebo. Baloxavir marboxil was well tolerated and no safety signals were identified. Full results from the CAPSTONE-2 study will be presented at upcoming medical meetings.

Baloxavir marboxil has already demonstrated a clinically significant benefit over placebo in otherwise healthy people in the Phase III CAPSTONE-1 study. The FDA recently accepted a New Drug Application (NDA) and granted Priority Review to baloxavir marboxil as a single-dose, oral treatment for acute, uncomplicated influenza in people 12 years and older based on the CAPSTONE-1 study and the Phase II study, and is expected to make a decision on approval by December 24, 2018. 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.

The study was conducted globally by Shionogi & Co., Ltd. Participants enrolled in the study were randomly assigned to receive a single dose of 40 mg or 80 mg of baloxavir marboxil (according to body weight), placebo or 75 mg of oseltamivir twice a day for five days. The primary objective of the study evaluated the efficacy of a single dose of baloxavir marboxil compared with placebo by measuring the time to improvement of influenza symptoms. Important secondary endpoints were time to resolution of fever, time to cessation of viral shedding and the proportion of participants positive for influenza virus titer, or virus levels in the body, by time point, and incidences of influenza-related complications.

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

Comment: Baloxavir marboxil was discovered by Shionogi & Co., Ltd. and is being developed globally by the Roche Group (which includes Genentech in the U.S.) and Shionogi & Co., Ltd. Under the terms of this agreement, Roche holds worldwide rights to baloxavir marboxil excluding Japan and Taiwan, which will be retained exclusively by Shionogi & Co., Ltd. Baloxavir marboxil was approved in February 2018 by the Japanese Ministry of Health, Labour and Welfare for the treatment of influenza types A and B in adult and pediatric patients, and is being commercialized in Japan and marketed under the brand name Xofluza.