For Patients and Caregivers

Help Prevent the Flu After Exposure1

XOFLUZA Is the Only Single-Dose Post-Exposure Prophylaxis Medication for Influenza (Patients Aged ≥5 Years)1

XOFLUZA® (baloxavir marboxil) Efficacy for Post-Exposure Flu Prophylaxis
In patients (aged ≥5 years) who were given single-dose XOFLUZA, their risk of contracting the flu after contact with an infected household member was reduced by 87% compared with patients who received placebo (2% XOFLUZA [95% CI: 1%, 4%] vs 13% placebo [95% CI: 10%, 17%]), corresponding to an estimated adjusted risk ratio of 0.14 (P<0.001), based on randomization factors.1,10

Trial T0834 was a phase 3, randomized, double-blind, multicenter, placebo-controlled trial designed to evaluate the efficacy of a single oral dose of XOFLUZA compared with placebo in the prevention of influenza in subjects who were household contacts of influenza-infected patients in Japan. Influenza-infected index patients were required to have onset of symptoms for ≤48 hours, and subjects (household contacts) were required to have lived with the influenza-infected index patient for ≥48 hours. A total of 715 subjects (XOFLUZA n=360, placebo n=355) aged 5 years and older were randomized and received a single oral dose of XOFLUZA according to body weight and age, or placebo, on Day 1. Subjects received a single dose of 40 mg or 80 mg of XOFLUZA according to body weight (20 kg to <80 kg or ≥80 kg, respectively). The primary efficacy endpoint was the proportion of household subjects who were infected with influenza virus and presented with fever and at least one respiratory symptom from Day 1 to Day 10. Influenza infection was confirmed by RT-PCR, fever was defined as a body temperature (axillary) ≥37.5°C, and respiratory symptoms were defined as having a symptom of “cough” or “nasal discharge/nasal congestion” with a severity of moderate or severe as assessed by the subject. In subjects that were 5 years of age and older, there was a statistically significant reduction in the proportion of household contacts (subjects) with laboratory-confirmed clinical influenza from 13% (n=47) in the placebo group to 2% (n=6) in the XOFLUZA group.1

RT-PCR = reverse transcription polymerase chain reaction.

XOFLUZA may be prescribed to patients 5 years and older who have been exposed to the flu, and it should be taken within 48 hours of exposure.1
XOFLUZA® (baloxavir marboxil) Sample Icon

Order a Sample of Single-Dose XOFLUZA

Sample a full course of flu treatment with single-dose XOFLUZA.1

Request sample >
XOFLUZA® (baloxavir marboxil) Safety Icon

Safety Profile

Single-dose XOFLUZA has a generally well-tolerated safety profile.1,2

See safety profile >

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 (e.g., 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 USA, Inc.

      XOFLUZA. Prescribing information. Genentech USA, Inc.

    • Baker J, Block SL, Matharu B, et al. Baloxavir marboxil single-dose treatment in influenza-infected children: a randomized, double-blind, active controlled phase 3 safety and efficacy trial (miniSTONE-2). Pediatr Infect Dis J. 2020;39(8):700-705. doi:10.1097/INF.0000000000002747

      Baker J, Block SL, Matharu B, et al. Baloxavir marboxil single-dose treatment in influenza-infected children: a randomized, double-blind, active controlled phase 3 safety and efficacy trial (miniSTONE-2). Pediatr Infect Dis J. 2020;39(8):700-705. doi:10.1097/INF.0000000000002747

    • TAMIFLU. Prescribing information. Genentech USA, Inc.; 2019.

      TAMIFLU. Prescribing information. Genentech USA, Inc.; 2019.

    • Hayden FG, Sugaya N, Hirotsu N, et al; Baloxavir Marboxil Investigators Group. Baloxavir marboxil for uncomplicated influenza in adults and adolescents. N Engl J Med. 2018;379(10):913-923.

      Hayden FG, Sugaya N, Hirotsu N, et al; Baloxavir Marboxil Investigators Group. Baloxavir marboxil for uncomplicated influenza in adults and adolescents. N Engl J Med. 2018;379(10):913-923.

    • Ison MG, Portsmouth S, Yoshida Y, et al. Early treatment with baloxavir marboxil in high-risk adolescent and adult outpatients with uncomplicated influenza (CAPSTONE-2): a randomised, placebo-controlled, phase 3 trial. Lancet Infect Dis. 2020;20(10):1204-1214. doi:10.1016/S1473-3099(20)30004-9

      Ison MG, Portsmouth S, Yoshida Y, et al. Early treatment with baloxavir marboxil in high-risk adolescent and adult outpatients with uncomplicated influenza (CAPSTONE-2): a randomised, placebo-controlled, phase 3 trial. Lancet Infect Dis. 2020;20(10):1204-1214. doi:10.1016/S1473-3099(20)30004-9

    • Ison MG, Portsmouth S, Yoshida Y, et al. Early treatment with baloxavir marboxil in high-risk adolescent and adult outpatients with uncomplicated influenza (CAPSTONE-2): a randomised, placebo-controlled, phase 3 trial. Lancet Infect Dis. 2020;20(10)(suppl):1-63. doi:10.1016/S1473-3099(20)30004-9

      Ison MG, Portsmouth S, Yoshida Y, et al. Early treatment with baloxavir marboxil in high-risk adolescent and adult outpatients with uncomplicated influenza (CAPSTONE-2): a randomised, placebo-controlled, phase 3 trial. Lancet Infect Dis. 2020;20(10)(suppl):1-63. doi:10.1016/S1473-3099(20)30004-9

    • Incalzi RA, Consoli A, Lopalco P, et al. Influenza vaccination for elderly, vulnerable and high-risk subjects: a narrative review and expert opinion. Intern Emerg Med. 2024;19(3):619-640.

      Incalzi RA, Consoli A, Lopalco P, et al. Influenza vaccination for elderly, vulnerable and high-risk subjects: a narrative review and expert opinion. Intern Emerg Med. 2024;19(3):619-640.

    • Green WD, Beck MA. Obesity impairs the adaptive immune response to influenza virus. Ann Am Thorac Soc. 2017;14(suppl 5):S406-S409.

      Green WD, Beck MA. Obesity impairs the adaptive immune response to influenza virus. Ann Am Thorac Soc. 2017;14(suppl 5):S406-S409.

    • United States Census Bureau. Caplan Z, Rabe M. The older population: 2020. May 2023. Accessed July 30, 2025. https://www2.census.gov/library/publications/decennial/2020/census-briefs/c2020br-07.pdf

      United States Census Bureau. Caplan Z, Rabe M. The older population: 2020. May 2023. Accessed July 30, 2025. https://www2.census.gov/library/publications/decennial/2020/census-briefs/c2020br-07.pdf

    • 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

    • Clinical signs and symptoms of influenza. Centers for Disease Control and Prevention. Last reviewed August 8, 2024. Accessed July 30, 2025.
      https://www.cdc.gov/flu/hcp/clinical-signs/index.html

      Clinical signs and symptoms of influenza. Centers for Disease Control and Prevention. Last reviewed August 8, 2024. Accessed July 30, 2025.
      https://www.cdc.gov/flu/hcp/clinical-signs/index.html

    • Estimated US flu disease burden. Centers for Disease Control and Prevention. Last reviewed May 9, 2025. Accessed July 30, 2025. https://www.cdc.gov/flu-burden/php/data-vis/2024-2025.html

      Estimated US flu disease burden. Centers for Disease Control and Prevention. Last reviewed May 9, 2025. Accessed July 30, 2025. https://www.cdc.gov/flu-burden/php/data-vis/2024-2025.html

    • Preventing seasonal flu. Centers for Disease Control and Prevention. Last reviewed August 26, 2024. Accessed July 30, 2025. https://www.cdc.gov/flu/prevention/

      Preventing seasonal flu. Centers for Disease Control and Prevention. Last reviewed August 26, 2024. Accessed July 30, 2025. https://www.cdc.gov/flu/prevention/

    • Symptoms of COVID-19. Centers for disease Control and Prevention. Last reviewed March 10, 2025. Accessed July 30, 2025. https://www.cdc.gov/covid/signs-symptoms/

      Symptoms of COVID-19. Centers for disease Control and Prevention. Last reviewed March 10, 2025. Accessed July 30, 2025. https://www.cdc.gov/covid/signs-symptoms/

    • Allan GM, Arroll B. Prevention and treatment of the common cold: making sense of the evidence. CMAJ. 2014;186(3):190-199. doi:10.1503/cmaj.121442

      Allan GM, Arroll B. Prevention and treatment of the common cold: making sense of the evidence. CMAJ. 2014;186(3):190-199. doi:10.1503/cmaj.121442

    • Cold versus the flu. Centers for Disease Control and Prevention. Last reviewed August 8, 2024. Accessed July 30, 2025. https://www.cdc.gov/flu/about/coldflu.html

      Cold versus the flu. Centers for Disease Control and Prevention. Last reviewed August 8, 2024. Accessed July 30, 2025. https://www.cdc.gov/flu/about/coldflu.html

    • Is it flu, COVID-19, allergies or a cold? National Institutes of Health. Last reviewed January 2022. Accessed July 30, 2025. https://newsinhealth.nih.gov/2022/01/it-flu-covid-19-allergies-or-cold

      Is it flu, COVID-19, allergies or a cold? National Institutes of Health. Last reviewed January 2022. Accessed July 30, 2025. https://newsinhealth.nih.gov/2022/01/it-flu-covid-19-allergies-or-cold

    • About adenovirus. Symptoms. Centers for Disease Control and Prevention. Last reviewed November 1, 2024. Accessed July 30, 2025. https://www.cdc.gov/adenovirus/about/index.html

      About adenovirus. Symptoms. Centers for Disease Control and Prevention. Last reviewed November 1, 2024. Accessed July 30, 2025. https://www.cdc.gov/adenovirus/about/index.html

    • Is it a cold, the flu, or COVID-19? National Institute on Aging. Last reviewed June 5, 2025. Accessed July 30, 2025. https://www.nia.nih.gov/health/covid-19/it-cold-flu-or-covid-19

      Is it a cold, the flu, or COVID-19? National Institute on Aging. Last reviewed June 5, 2025. Accessed July 30, 2025. https://www.nia.nih.gov/health/covid-19/it-cold-flu-or-covid-19

    • COVID-19 Treatment Guidelines Panel. Coronavirus Disease 2019 (COVID-19) Treatment Guidelines. National Institutes of Health. Updated February 29, 2024. Accessed July 30, 2025. https://www.ncbi.nlm.nih.gov/books/NBK570371/pdf/Bookshelf_NBK570371.pdf

      COVID-19 Treatment Guidelines Panel. Coronavirus Disease 2019 (COVID-19) Treatment Guidelines. National Institutes of Health. Updated February 29, 2024. Accessed July 30, 2025. https://www.ncbi.nlm.nih.gov/books/NBK570371/pdf/Bookshelf_NBK570371.pdf

    • Influenza antiviral medications: summary for clinicians. Centers for Disease Control and Prevention. Last reviewed December 8, 2023. Accessed July 30, 2025. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html

      Influenza antiviral medications: summary for clinicians. Centers for Disease Control and Prevention. Last reviewed December 8, 2023. Accessed July 30, 2025. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html

    • Emerging infectious diseases: influenza A(H1N1)pdm09 virus with reduced susceptibility to baloxavir, Japan, 2024. Centers for Disease Control and Prevention. May 2025. Accessed July 30,2025. https://wwwnc.cdc.gov/eid/article/31/5/24-1123_article

      Emerging infectious diseases: influenza A(H1N1)pdm09 virus with reduced susceptibility to baloxavir, Japan, 2024. Centers for Disease Control and Prevention. May 2025. Accessed July 30,2025. https://wwwnc.cdc.gov/eid/article/31/5/24-1123_article

    • 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.

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

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

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

      Fiore AE, Fry A, Shay D, Gubareva L, Bresee JS, Uyeki TM. Antiviral agents for the treatment and chemoprophylaxis of influenza—recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2011;60(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

    • 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