What is the efficacy of Baloxavir (Baloxavir marboxil) treatment in preventing the transmission of influenza?

From the Guidelines

Baloxavir is effective in preventing the transmission of influenza when administered as a single oral dose within 48 hours of exposure to a symptomatic household contact with influenza, with a significant reduction in the proportion of household members who develop influenza. The medication works by inhibiting the cap-dependent endonuclease enzyme, preventing viral replication and significantly reducing viral shedding within 24 hours of administration 1. For optimal effectiveness, baloxavir should be administered as a single oral dose within 48 hours of symptom onset. The standard dosing is weight-based: 40mg for patients weighing 40-80kg and 80mg for those weighing more than 80kg.

Some key points to consider when using baloxavir for preventing influenza transmission include:

• The medication is generally well-tolerated, with common side effects including diarrhea, bronchitis, and nausea 1.
• Baloxavir is not specifically approved as a prophylactic measure for contacts, but its ability to quickly reduce viral shedding makes it valuable in limiting spread within households, dormitories, and other close-contact settings 1.
• The American Academy of Pediatrics (AAP) recommends oseltamivir as the preferred postexposure chemoprophylaxis for patients with influenza A and/or B, but baloxavir may be considered as an alternative when compliance is a concern or there is poor tolerance of an antiviral regimen requiring multiple medication doses 1.
• The Centers for Disease Control and Prevention (CDC) recommends routine chemoprophylaxis with oseltamivir or zanamivir for 7 days after last known exposure, but baloxavir may be used as an alternative in certain situations 1.

Overall, baloxavir is a valuable option for preventing the transmission of influenza, particularly in household settings, and should be considered as part of a comprehensive strategy to control and prevent influenza.

From the FDA Drug Label

The relationship between antiviral activity in cell culture and clinical response to treatment in humans has not been established.

The FDA drug label does not answer the question.

From the Research

Efficacy of Baloxavir in Preventing Transmission of Influenza

• The study 2 found that baloxavir marboxil significantly reduced the transmission of influenza virus from index patients to household contacts, with an adjusted relative risk reduction of 29%.
• The adjusted incidence of transmission of laboratory-confirmed influenza was 9.5% with baloxavir and 13.4% with placebo.
• Another study 3 demonstrated the efficacy of baloxavir in treating uncomplicated influenza in high-risk adolescent and adult outpatients, with a median time to improvement of influenza symptoms of 73.2 hours, compared to 102.3 hours with placebo.
• A phase 3 trial 4 showed that single-dose baloxavir was superior to placebo in alleviating influenza symptoms, with a median time to alleviation of symptoms of 53.7 hours, compared to 80.2 hours with placebo.

Safety and Efficacy of Baloxavir

• The study 4 found that baloxavir was associated with a lower incidence of adverse events, with 20.7% of baloxavir recipients reporting adverse events, compared to 24.6% of placebo recipients and 24.8% of oseltamivir recipients.
• A systematic review and meta-analysis 5 found that baloxavir was associated with a lower risk of any adverse events than oseltamivir and placebo.
• The study 6 reported two cases of immunocompromised patients treated with baloxavir for oseltamivir-resistant influenza A/H1pdm09, with one patient showing effective treatment with baloxavir/zanamivir combination therapy, and the other patient experiencing persistent viral shedding with baloxavir monotherapy.

Comparison with Other Anti-Influenza Agents

• The systematic review and meta-analysis 5 found that baloxavir had a significantly shorter time to alleviation of symptoms than placebo, but an insignificantly shorter time to alleviation of symptoms than oseltamivir.
• The study 3 found that baloxavir had similar efficacy to oseltamivir in treating uncomplicated influenza in high-risk adolescent and adult outpatients.
• The study 4 found that baloxavir was superior to oseltamivir and placebo in reducing viral load 1 day after initiation of the trial regimen.