Another fighter against the flu

OSAKA, Japan & FLORHAM PARK, N.J.—Shionogi & Co., Ltd. has announced today that the positive results from Phase II and III studies of baloxavir marboxil for the treatment of influenza in otherwise healthy patients have been published in the September 6, 2018 issue of the New England Journal of Medicine.

Baloxavir marboxil was discovered and developed by Shionogi, and has a novel mechanism of action that inhibits viral cap-dependent endonuclease, an essential enzyme for viral replication. The regimen for baloxavir marboxil is a single oral dose to treat uncomplicated influenza, which is different from most currently available antiviral treatments. In non-clinical studies, baloxavir marboxil demonstrated an antiviral effect against a wide range of influenza viruses, including oseltamivir-resistant strains and avian strains (H7N9, H5N1).

In the Phase II study conducted in adults in Japan, baloxavir marboxil demonstrated a reduction in time to alleviation of symptoms, and in influenza virus titers compared with the placebo. In the global Phase III study (CAPSTONE-1) in patients 12 years of age and older, baloxavir marboxil reduced time to alleviations of symptoms (TTAS) compared with the placebo. On the other hand, there was no statistical difference in TTAS between baloxavir marboxil and oseltamivir.

Of note, baloxavir marboxil demonstrated more rapid declines in infectious virus titers compared with both the placebo and oseltamivir. Regarding safety, baloxavir marboxil was well tolerated with a numerically lower overall incidence of adverse events compared with both the placebo and oseltamivir.

“In addition to its favorable safety and pharmacokinetic profile enabling single dose oral therapy in uncomplicated influenza, baloxavir marboxil’s antiviral potency offers promise of potentially reducing complications and transmission of the virus to others, and in treating more serious forms of influenza illness. It also addresses an important unmet medical need in inhibiting influenza viruses that are resistant to currently available agents,” said Frederick G. Hayden, M.D., Stuart S. Richardson Professor Emeritus of Clinical Virology and Professor Emeritus of Medicine, University of Virginia School of Medicine, the lead author of the published paper.

Baloxavir marboxil has had a busy 2018. In February, it was approved under the brand name XOFLUZA in Japan for the treatment of influenza types A and B in adults and pediatric patients. April saw Shionogi submitting a New Drug Application (NDA) to the United States Food and Drug Administration (FDA) for the treatment of acute uncomplicated influenza in patients 12 years of age and older in collaboration with F. Hoffmann-La Roche Ltd. On June 26, the FDA accepted the NDA and granted Priority Review. The Prescription Drug User Fee Act (PDUFA) date for an FDA decision is December 24, 2018.

Shionogi submitted in June an NDA for baloxavir marboxil in Taiwan for the treatment of influenza in patients 12 years of age and older. The company also announced positive top-line results of CAPSTONE-2, a Phase III study in patients at high risk for influenza-related complications in July, the results of which will be presented at upcoming medical meetings.

Shionogi and the Roche Group, which includes Genentech in the U.S., are in a license and collaboration agreement to further develop and commercialize baloxavir marboxil globally. Under the terms of this agreement, the Roche Group holds worldwide rights to baloxavir marboxil, excluding Japan and Taiwan, where the rights are retained exclusively by Shionogi. Roche will further investigate baloxavir marboxil in a global Phase III development program, including pediatric and severely ill hospitalized populations with influenza. Shionogi plans to conduct a post-exposure Phase III prophylaxis study in Japan in the 2018/2019 flu season.