What is Xofluza (Baloxavir marboxil)?

From the Guidelines

Xofluza (baloxavir marboxil) is an effective antiviral medication used to treat influenza (flu) in patients 12 years and older who have been symptomatic for less than 48 hours, with a standard dosage of a single oral dose based on weight: 40 mg for patients weighing 40-80 kg and 80 mg for those weighing more than 80 kg, as recommended by the most recent guidelines 1.

Key Points

• The medication works by inhibiting the cap-dependent endonuclease enzyme, preventing the virus from replicating within the body 1.
• For maximum effectiveness, Xofluza should be taken as soon as possible after symptom onset and should not be taken with dairy products, calcium-fortified beverages, laxatives, or antacids containing calcium, iron, magnesium, selenium, or zinc, as these can reduce the medication's absorption 1.
• Common side effects include diarrhea, bronchitis, nausea, and headache 1.
• While Xofluza can reduce the duration of flu symptoms by about 24 hours, it is not a substitute for annual flu vaccination, which remains the primary preventive measure against influenza 1.

Dosage and Administration

• The standard dosage is a single oral dose based on weight: 40 mg for patients weighing 40-80 kg and 80 mg for those weighing more than 80 kg 1.
• Xofluza should be taken as soon as possible after symptom onset 1.

Important Considerations

• Xofluza is not recommended as monotherapy for treatment of influenza in individuals who are severely immunocompromised 1.
• It is not recommended for persons who are pregnant or breastfeeding 1.
• The effectiveness of LAIV but not IIV or RIV will be decreased for children receiving oseltamivir or other influenza antiviral agents, including Xofluza 1.

From the FDA Drug Label

XOFLUZA is a prescription medicine used to: treat the flu (influenza) in people 12 years of age and older who have had flu symptoms for no more than 48 hours prevent the flu in people 12 years of age and older following contact with a person who has the flu.

XOFLUZA is used to treat and prevent influenza in people 12 years of age and older.

• Treatment: XOFLUZA is used to treat the flu in people 12 years of age and older who have had flu symptoms for no more than 48 hours.
• Prevention: XOFLUZA is used to prevent the flu in people 12 years of age and older following contact with a person who has the flu. The safety and efficacy of XOFLUZA in pediatric subjects less than 12 years of age have not been established for the treatment of acute uncomplicated influenza 2. The safety and efficacy of XOFLUZA for post-exposure prophylaxis of influenza in pediatric subjects less than 12 years of age have not been established 2.

From the Research

Xofluza Overview

• Xofluza, also known as Baloxavir Marboxil, is a first-in-class, small molecule inhibitor of the polymerase acidic (PA) protein subunit of the influenza virus polymerase complex 3.
• It is approved in the USA for the treatment of acute uncomplicated influenza in patients ≥ 12 years of age who have been symptomatic for ≤ 48 hours 3.

Efficacy and Safety

• Baloxavir has been shown to be efficacious in improving influenza symptoms in otherwise healthy adolescents and adults, as well as in those at high risk of influenza complications, with similar efficacy to oseltamivir 3, 4.
• It has also been shown to reduce influenza viral load more rapidly than oseltamivir 3, 4.
• Baloxavir is well tolerated, with a similar incidence of adverse events to oseltamivir 4, 5.
• A systematic review and meta-analysis found that baloxavir was safer and more effective than oseltamivir in patients with influenza virus infections, with a lower incidence of adverse events and shorter hospitalization period 6.

Real-World Effectiveness

• A real-world study found that baloxavir was superior to oseltamivir in alleviating influenza symptoms in outpatients with uncomplicated influenza, with a shorter time to alleviation of symptoms and fever 5.
• Another study found that single-dose baloxavir was effective in preventing influenza in household contacts of patients with influenza, with a significant reduction in the risk of clinical influenza 7.

Resistance and Transmission

• There is evidence of the emergence and transmission of variant viruses with reduced susceptibility to baloxavir, highlighting the importance of monitoring and surveillance for changes in influenza virus drug susceptibility patterns 3, 4, 7.
• However, the risk of transmission of these variants from baloxavir-treated index patients to household contacts was found to be low 7.