Baloxavir marboxil was discovered by Shionogi & Co. and is being developed globally by the Roche Group (which includes Genentech in the US) and Shionogi & Co.
The drug achieved the primary objective of the study and demonstrated superior efficacy in the primary endpoint of time to improvement of influenza symptoms against placebo.
Baloxavir marboxil is a single-dose investigational oral medicine with a novel proposed mechanism of action designed to target the influenza (flu) A and B viruses such as oseltamivir-resistant strains and avian strains.
The Capstone-2 is a multicentre, randomized and double-blind study designed to assess a single dose of baloxavir marboxil compared with placebo and oseltamivir in people 12 years or older who are at a high risk of complications from the flu.
Baloxavir marboxil also showed superior efficacy compared against placebo and oseltamivir for secondary endpoints, including reducing the time that the virus continued to be released and reducing viral levels in the body.
The flu drug also significantly reduced the incidence of influenza-related complications compared against placebo.
Earlier, baloxavir marboxil showed a clinically significant benefit over placebo in otherwise healthy people in the phase III Capstone-1 study.
Recently, the US Food and Drug Administration (FDA) 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.
The NDA was accepted based on the Capstone-1 study and the phase II study, and the FDA is expected to take a decision on approval in December this year.
Roche chief medical officer and global product development head Dr Sandra Horning said: “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.
“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.”