Stop Viral Replication Across a Broad Range of Flu Strains1

Active even against key oseltamivir-resistant and avian strains of the flu*

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

Influenza A and B viruses with treatment-emergent amino acid substitutions at positions associated with reduced susceptibility to baloxavir in cell culture were observed in clinical studies. The most common substitution emerging during baloxavir treatment is PA-I38X.1,13

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

*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

Single-Dose XOFLUZA Interrupts the Flu Viral Life Cycle Early, Helping Prevent Replication1,14

First-in-its-class XOFLUZA has a proposed mechanism of action (MOA) that works differently to stop the flu at its source1,15

XOFLUZA® (baloxavir marboxil) MOA - Mechanism of Action
  1. Viral entry14
    • The flu virus enters the host cell.
  2. Uncoating16,17
    • M2 ion channel blockers/adamantanes target viral uncoating; however, they are no longer recommended by the CDC due to high resistance.
  3. Viral replication14
    • The novel MOA of single-dose XOFLUZA works by inhibiting polymerase acidic (PA) endonuclease to prevent viral replication.1,15‡
  4. Viral assembly and budding14
    • Neuraminidase inhibitors, such as oseltamivir, target viral release.18
  5. Viral release from the host cell14,18
    • Once targeted, the already-replicated viruses are prevented from leaving the host cell.

*Source: Centers for Disease Control and Prevention (CDC). The CDC does not endorse private products, services, or enterprises. The content provided is for informational purposes only. Find the latest at

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


XOFLUZA is an influenza virus polymerase acidic (PA) endonuclease inhibitor indicated for the treatment of acute uncomplicated influenza in patients 12 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

XOFLUZA is also indicated for post-exposure prophylaxis (PEP) of influenza in patients 12 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

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

 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.


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 clinical studies for acute uncomplicated influenza were diarrhea (3%), bronchitis (3%), nausea (2%), sinusitis (2%), and headache (1%).

The most common adverse reaction in a clinical study for post-exposure prophylaxis (PEP) was nasopharyngitis (6%).


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 or calling 1-800-FDA-1088.