• Data from the CENTERSTONE study shows single-dose Xofluza reduces transmission of influenza from an infected person to household members 
• This is the first time that any antiviral used in the treatment of a respiratory viral illness has demonstrated a transmission reduction benefit in a global Phase III study 
• Reducing the spread of infection in the household could help limit transmission within communities and societies, easing the burden of both seasonal and pandemic influenza on healthcare systems 

SOUTH SAN FRANCISCO, Calif. / Sep 19, 2024 / Business Wire / Genentech, a member of the Roche Group (SIX: RO, ROG; OTCQX: RHHBY), announced today positive topline results of the Phase III CENTERSTONE study of Xofluza^® (baloxavir marboxil), an antiviral, showing a reduction in the transmission of influenza viruses. The study met its primary endpoint, demonstrating that a single, oral dose of Xofluza taken by people infected with influenza significantly reduced the likelihood of others in their household contracting the virus. Xofluza was well tolerated with no new safety signals identified.

CENTERSTONE is the first global Phase III study to show a transmission reduction benefit with an antiviral used in the treatment of a respiratory viral illness. This new data may add to the benefits of Xofluza which is currently approved for treating symptoms and preventing infection following virus exposure. The topline results will be presented at the 2024 OPTIONS XII for the Control of Influenza Congress (September 29 - October 2, Brisbane, Australia).

“Building on Xofluza’s established efficacy in treating and preventing influenza after exposure, this new evidence of transmission reduction represents an important advance that could help improve health outcomes at an individual and community level,” said Levi Garraway, M.D., Ph.D., chief medical officer and head of Global Product Development. “We look forward to discussing these data with regulatory authorities and public health organizations for influenza pandemic preparedness to bring these benefits to patients.”

Influenza is one of the most common yet serious infectious diseases representing a significant burden to public health. In the U.S., since 2010, seasonal influenza has infected up to 41 million people and has caused thousands of hospitalizations and 51,000 deaths annually. With the co-circulation and burden of multiple respiratory viruses (including COVID-19) infecting individuals within and outside of the winter season, it is more important than ever that influenza is not underestimated. For effective control of both seasonal and pandemic influenza, early diagnosis and treatment is critical.

The CENTERSTONE study has been partially supported with federal funds from the U.S. Department of Health and Human Services; Administration for Strategic Preparedness and Response; Biomedical Advanced Research and Development Authority, under Other Transaction Agreement number: HHSO100201800036C.

About CENTERSTONE

The CENTERSTONE study [NCT03969212] was a global Phase III trial investigating the efficacy of single-dose Xofluza, taken within 48 hours of symptoms onset, to reduce the onward transmission of influenza within households. The study ran across 272 sites across the globe, with over 4,000 participants, and involved otherwise healthy patients from five to 64 years who had been diagnosed with influenza via a Polymerase Chain Reaction (PCR) or rapid influenza diagnostic test, known as index patients (IPs) and those within their household (known as household contacts, HHCs). The primary endpoint was the proportion of HHCs who tested positive for influenza within five days after the IP had been treated with either Xofluza or placebo. The secondary endpoint looked at the proportion of HHCs who tested positive for influenza by Day five and developed influenza symptoms. The design of this randomized, placebo-controlled trial was developed with inputs from the U.S. Food and Drug Administration and leading experts in influenza.

About Xofluza^® (baloxavir marboxil)

Xofluza is a first-in-class, single-dose oral medicine with an innovative mechanism of action designed to block viral replication by inhibiting the cap-dependent endonuclease protein, potentially reducing the duration of infectiousness and disease. Xofluza’s mechanism of action has demonstrated efficacy in a wide range of influenza viruses, including in vitro activity against oseltamivir-resistant strains and avian strains (H7N9, H5N1) in non-clinical studies.

Xofluza is approved in more than 80 countries for the treatment of uncomplicated influenza types A and B. In the U.S., Xofluza is approved for the treatment of influenza in people five years of age and older who have been symptomatic for no more than 48 hours and who are otherwise healthy or at high risk of developing influenza-related complications, and to prevent influenza in people five years of age and older following contact with a person who has the flu (post-exposure prophylaxis). Xofluza represents the first innovation in mechanism of action for an influenza antiviral approved in almost 20 years for treatment in children five and older, adolescents, and adults.

Xofluza was discovered by Shionogi & Co., Ltd. and is being further developed and commercialized globally in collaboration with 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 Xofluza excluding Japan and Taiwan, which will be retained exclusively by Shionogi & Co., Ltd.

Xofluza U.S. Indication

XOFLUZA is a prescription medicine used to:

• treat the flu (influenza) in people 5 years of age and older who have flu symptoms for no more than 48 hours and who are:
  • otherwise healthy or
  • at high risk of developing problems from the flu
• prevent the flu in people 5 years of age and older following contact with a person who has the flu (post-exposure prophylaxis).

XOFLUZA does not treat or prevent illness that is caused by infections other than the influenza virus.

XOFLUZA does not prevent bacterial infections that may happen with the flu.

It is not known if XOFLUZA is safe and effective for the treatment and prevention of the flu in children less than 5 years of age. XOFLUZA is not for use in children less than 5 years of age.

Important Safety Information

Who should not take XOFLUZA?

• Do not take XOFLUZA if you are allergic to baloxavir marboxil or any of the ingredients in XOFLUZA

What should I tell my healthcare provider before using XOFLUZA?

• Tell your healthcare provider about all of your medical conditions, including if you are:
  • Pregnant or plan to become pregnant. It is not known if XOFLUZA can harm your unborn baby.
  • Breastfeeding or plan to breastfeed. It is not known if XOFLUZA passes into your breast milk.
• Talk to your healthcare provider before you receive a live flu vaccine after taking XOFLUZA.
• Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, antacids, laxatives, vitamins, and herbal supplements.

What are the possible side effects of XOFLUZA?

Serious side effects may include

• Allergic reaction. Get emergency medical help right away if you develop any of the following signs or symptoms of an allergic reaction:
  • trouble breathing
  • skin rash, hives or blisters
  • swelling of your face, throat or mouth
  • dizziness or lightheadedness

The most common side effects of XOFLUZA for treatment of the flu in adults and adolescents (12 years of age and older) were diarrhea, bronchitis, nausea, sinusitis, and headache.

The most common side effects of XOFLUZA for treatment of the flu in children (5 years of age to less than 12 years of age) were diarrhea and vomiting.

These are not all the possible side effects of XOFLUZA. Call your healthcare provider for medical advice about side effects.

XOFLUZA is not effective in treating or preventing infections other than influenza. Other kinds of infections can have symptoms like those of the flu or occur along with flu and may need different kinds of treatment. Tell your healthcare provider if you feel worse or develop new symptoms during or after treatment with XOFLUZA or if your flu symptoms do not start to get better.

You are encouraged to report side effects to Genentech by calling 1-888-835-2555 or to the FDA by visiting http://www.fda.gov/medwatch or calling 1-800-FDA-1088.

Please see full Prescribing Information, including Patient Product Information.

About Genentech in Influenza

Influenza is a serious infectious disease and represents a significant burden to public health. In the U.S., since 2010, seasonal influenza has infected up to 41 million people and has caused thousands of hospitalizations and 51,000 deaths every year. Genentech has a long history of developing transformative medicines that contribute to public health. We are committed to bringing innovation in the field of infectious diseases, including influenza. Tamiflu^® (oseltamivir) has made a significant difference in the treatment of both, seasonal influenza and pandemic management, and we are proud to have brought this innovative medicine to patients. Genentech, a member of the Roche Group, is committed to addressing the unmet need in this area through Roche’s agreement with Shionogi & Co., Ltd. to develop and commercialize Xofluza^® (baloxavir marboxil) in the U.S. market.

About Genentech

Founded more than 40 years ago, Genentech is a leading biotechnology company that discovers, develops, manufactures and commercializes medicines to treat patients with serious and life-threatening medical conditions. The company, a member of the Roche Group, has headquarters in South San Francisco, California. For additional information about the company, please visit http://www.gene.com.