For Patients and Caregivers

A Proposed MOA That Stops Viral Replication Across a Broad Range of Flu Strains1

Active Even Against Key Oseltamivir-Resistant Strains and Avian Strains of the Flu1*

XOFLUZA® (baloxavir marboxil) is effective against a broad range of A & B flu strains including A/H1N1, Avian A/H5N1 and others.

Antiviral activity was determined against laboratory strains and clinical isolates in vitro. The relationship between antiviral activity in cell culture and clinical response to treatment in humans has not been established.1

Selection of influenza viruses with treatment-emergent amino acid substitutions associated with reduced susceptibility to baloxavir has occurred at higher frequencies in pediatric subjects 5 to <12 years of age compared to subjects ≥12 years of age. The most common substitution emerging during baloxavir treatment is PA-138T.1-3

Consider available information on influenza virus types or subtypes and on drug susceptibility patterns for circulating influenza virus strains when deciding whether to prescribe XOFLUZA.1

Single-Dose XOFLUZA Interrupts the Flu Viral Life Cycle Early, Helping Prevent Replication1,4

First-in-its-class XOFLUZA has a proposed mechanism of action (MOA) that works differently to stop the flu at its source1,5,6

XOFLUZA® (baloxavir marboxil) MOA - Mechanism of Action
  1. Viral entry4
    • The flu virus enters the host cell
  2. Uncoating6,7
    • M2 ion channel blockers/adamantanes target viral uncoating; however, they are no longer recommended by the CDC due to high resistance
  3. Viral replication1,5
    • The novel MOA of single-dose XOFLUZA works by inhibiting polymerase acidic (PA) endonuclease to prevent viral replication
  4. Viral assembly and budding4,8
    • Neuraminidase inhibitors, such as oseltamivir, target viral release
  5. Viral release from the host cell4,8
    • Once targeted, the already-replicated viruses are prevented from leaving the host cell

ER = endoplasmic reticulum.

XOFLUZA® (baloxavir marboxil) Single Dose Icon
Treatment in a Single Dose

Keep it simple with a full course of treatment in a single dose.1

Single-dose Rx
XOFLUZA® (baloxavir marboxil) Safety Icon
Help Prevent the Flu

Patients can reduce their risk of contracting the flu after exposure to an infected household member by taking single-dose XOFLUZA.1

Post-exposure prophylaxis efficacy

Frequently
asked
questions

XOFLUZA (baloxavir marboxil) is an oral influenza antiviral. It is an influenza virus polymerase acidic (PA) endonuclease inhibitor, a prodrug that converts to baloxavir, which inhibits the PA endonuclease, an influenza virus-specific enzyme required for viral gene transcription, thereby inhibiting influenza virus replication.1

XOFLUZA is taken as a single, weight-based oral dose.1 Please refer to the XOFLUZA Prescribing Information for the most current FDA-approved indications.

Potential candidates include patients 5 years of age and older with acute uncomplicated influenza whose symptoms began within the 48-hour treatment window, including otherwise healthy patients and patients at high risk for influenza-related complications. It is also indicated for post-exposure prophylaxis of influenza in patients 5 years of age and older following contact with an individual who has influenza.1

Treatment decisions should consider clinical presentation, timing from symptom onset, influenza activity, patient-specific risk factors, and current CDC or local public health guidance. XOFLUZA is not a substitute for annual influenza vaccination.

Please refer to the XOFLUZA Prescribing Information for the most current FDA-approved indications.

For treatment, XOFLUZA should be initiated as soon as possible and within 48 hours of influenza symptom onset, per the US label.1

Patients should be managed according to current clinical guidelines and institutional protocols.

Yes. In the US, XOFLUZA is indicated for post-exposure prophylaxis of influenza in patients 5 years of age and older following contact with an individual who has influenza.1

Post-exposure prophylaxis decisions should consider exposure history, timing, patient-specific risk factors, and current CDC or local public health guidance. Xofluza is not a substitute for annual influenza vaccination.

Yes. XOFLUZA is approved for the treatment of acute uncomplicated influenza in patients 5 years of age and older who have been symptomatic for no more than 48 hours. Clinical studies of XOFLUZA for the treatment of influenza included patients with influenza A (predominantly A/H1N1 and A/H3N2) and influenza B.

Treatment decisions should weigh the potential benefits and risks, disease severity, and patient risk factors, together with the current Prescribing Information and guidance from the Centers for Disease Control and Prevention (CDC) or local public health authorities.

IMPORTANT SAFETY INFORMATION & INDICATION

Indication

XOFLUZA is an influenza virus polymerase acidic (PA) endonuclease inhibitor indicated for:

  • Treatment of acute uncomplicated influenza in patients 5 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.
  • Post-exposure prophylaxis (PEP) of influenza in patients 5 years of age and older following contact with an individual who has influenza.

Limitations of Use
Influenza viruses change over time, and factors such as the virus type or subtype, emergence of resistance, or changes in viral virulence could diminish the clinical benefit of antiviral drugs. Consider available information on drug susceptibility patterns for circulating influenza virus strains when deciding whether to use XOFLUZA.

Important Safety Information

Contraindications
XOFLUZA is contraindicated in patients with a history of hypersensitivity to baloxavir marboxil or any of its ingredients. Serious allergic reactions have included anaphylaxis, angioedema, urticaria, and erythema multiforme.

Warnings and Precautions

Hypersensitivity: Cases of anaphylaxis, urticaria, angioedema, and erythema multiforme have been reported in postmarketing experience with XOFLUZA. Appropriate treatment should be instituted if an allergic-like reaction occurs or is suspected.

Increased Incidence of Treatment-Emergent Resistance in Patients Less Than 5 Years of Age: XOFLUZA is not indicated in patients less than 5 years of age due to increased incidence of treatment-emergent resistance in this age group. In clinical trials, the incidence of virus with treatment-emergent substitutions associated with reduced susceptibility to baloxavir (resistance) was higher in pediatric subjects younger than 5 years of age (40%, 38/96) than in pediatric subjects ≥5 years to <12 years of age (16%, 19/117) or subjects ≥12 years of age (7%, 60/842). The potential for transmission of resistant strains in the community has not been determined.

Risk of bacterial infections: There is no evidence of the efficacy of XOFLUZA in any illness caused by pathogens other than influenza viruses. Serious bacterial infections may begin with influenza-like symptoms or may coexist with, or occur as, a complication of influenza. XOFLUZA has not been shown to prevent such complications. Prescribers should be alert to potential secondary bacterial infections and treat them as appropriate.

Adverse Reactions

  • The most common adverse reactions (≥1%) in adult and adolescent patients (≥12 years of age) in clinical studies for acute uncomplicated influenza were diarrhea (3%), bronchitis (3%), nausea (2%), sinusitis (2%), and headache (1%).
  • The most frequently reported adverse reactions (≥5%) in pediatric patients (5 to <12 years of age) in clinical studies for acute uncomplicated influenza were vomiting (5%) and diarrhea (5%).
  • The safety profile reported in a clinical study for post-exposure prophylaxis was similar in pediatric patients ages 5 to <12 years old as that reported in adults and adolescents 12 years of age and older.

Drug Interactions
Polyvalent cations: Coadministration with polyvalent cation-containing products may decrease plasma concentrations of baloxavir, which may reduce XOFLUZA efficacy. Avoid coadministration of XOFLUZA with dairy products, calcium-fortified beverages, polyvalent cation-containing laxatives, antacids, or oral supplements (eg, calcium, iron, magnesium, selenium, or zinc).

Vaccines: The concurrent use of XOFLUZA with intranasal live attenuated influenza vaccine (LAIV) has not been evaluated. Concurrent administration of antiviral drugs may inhibit viral replication of LAIV and, thereby, decrease the effectiveness of LAIV vaccination. Interactions between inactivated influenza vaccines and XOFLUZA have not been evaluated.

For additional Important Safety Information, please see the XOFLUZA full Prescribing Information.

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

    • XOFLUZA. Prescribing information. Genentech, Inc.

      XOFLUZA. Prescribing information. Genentech, Inc.

    • Ikematsu H, Hayden FG, Kawaguchi K, et al. Baloxavir marboxil for prophylaxis against influenza in household contacts. N Engl J Med. 2020;383(4):309-320. doi:10.1056/NEJMoa1915341

      Ikematsu H, Hayden FG, Kawaguchi K, et al. Baloxavir marboxil for prophylaxis against influenza in household contacts. N Engl J Med. 2020;383(4):309-320. doi:10.1056/NEJMoa1915341

    • Emerging infectious diseases: influenza A(H1N1)pdm09 virus with reduced susceptibility to baloxavir, Japan, 2024. Centers for Disease Control and Prevention. May 2025. Accessed August 18, 2026. https://wwwnc.cdc.gov/eid/article/31/5/24-1123-f1

      Emerging infectious diseases: influenza A(H1N1)pdm09 virus with reduced susceptibility to baloxavir, Japan, 2024. Centers for Disease Control and Prevention. May 2025. Accessed August 18, 2026. https://wwwnc.cdc.gov/eid/article/31/5/24-1123-f1

    • Samji T. Influenza A: understanding the viral life cycle. Yale J Biol Med. 2009;82(4):153-159.

      Samji T. Influenza A: understanding the viral life cycle. Yale J Biol Med. 2009;82(4):153-159.

    • Influenza antiviral medications: summary for clinicians. Centers for Disease Control and Prevention. Last reviewed March 10, 2026. Accessed August 21, 2026. https://www.cdc.gov/​flu/​hcp/​antivirals/​summary-clinicians.html

      Influenza antiviral medications: summary for clinicians. Centers for Disease Control and Prevention. Last reviewed March 10, 2026. Accessed August 21, 2026. https://www.cdc.gov/​flu/​hcp/​antivirals/​summary-clinicians.html

    • De Clercq E, Li G. Approved antiviral drugs over the past 50 years. Clin Microbiol Rev. 2016;29(3):695-747. doi:10.1128/CMR.00102-15

      De Clercq E, Li G. Approved antiviral drugs over the past 50 years. Clin Microbiol Rev. 2016;29(3):695-747. doi:10.1128/CMR.00102-15

    • Fiore AE, Fry A, Shay D, Gubareva L, Bresee JS, Uyeki TM; Centers for Disease Control and Prevention. Antiviral agents for the treatment and chemoprophylaxis of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2011;60(RR-1):1-24.

      Fiore AE, Fry A, Shay D, Gubareva L, Bresee JS, Uyeki TM; Centers for Disease Control and Prevention. Antiviral agents for the treatment and chemoprophylaxis of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2011;60(RR-1):1-24.

    • von Itzstein M. The war against influenza: discovery and development of sialidase inhibitors. Nat Rev Drug Discov. 2007;6(12):967-974. doi:10.1038/nrd2400

      von Itzstein M. The war against influenza: discovery and development of sialidase inhibitors. Nat Rev Drug Discov. 2007;6(12):967-974. doi:10.1038/nrd2400

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