New Drug Reviews

Baloxavir Marboxil (Xofluza) for Influenza


Am Fam Physician. 2019 Dec 15;100(12):776-777.

Baloxavir marboxil (Xofluza) is an antiviral medication with a novel mechanism that inhibits an influenza virus–specific enzyme necessary for viral gene transcription and prevents influenza A and B virus replication. Baloxavir is labeled for the treatment of acute uncomplicated influenza in patients 12 years and older who have been symptomatic for no more than 48 hours.

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DrugDosageDose formCost*

Baloxavir marboxil (Xofluza)

Weight-based dosing: 40 mg or 80 mg taken one time

20-mg or 40-mg tablets


*—Estimated retail price of one dose based on information obtained at (accessed October 28, 2019).

DrugDosageDose formCost*

Baloxavir marboxil (Xofluza)

Weight-based dosing: 40 mg or 80 mg taken one time

20-mg or 40-mg tablets


*—Estimated retail price of one dose based on information obtained at (accessed October 28, 2019).


A significant safety concern about baloxavir is that as an antiviral medication, it has no action against bacterial infections. Bacterial superinfections may occur in patients already infected with influenza, and treating influenza with baloxavir will not prevent or treat any secondary bacterial infections. Patients taking this medication do not require monitoring. Baloxavir has not been studied in children younger than 12 years, adults older than 65 years, or pregnant or lactating women.


Baloxavir is well tolerated by most patients. Reported adverse effects include diarrhea (3%), bronchitis (2%), nasopharyngitis (1%), nausea (1%), and headache (1%). These rates are all equal to or less than the same effects from placebo.1


Baloxavir has been studied in healthy patients and in those considered to be at high risk for influenza complications (e.g., patients with asthma, lung disease, heart disease, or morbid obesity).1,2 Baloxavir has been compared with placebo and with the neuraminidase inhibitor, oseltamivir (Tamiflu), in two randomized controlled trials over two different influenza seasons (2015 to 2016 and 2016 to 2017) involving a total of 1,836 otherwise healthy patients with influenza symptoms for no more than 48 hours, most of whom had polymerase chain reaction (PCR)-confirmed influenza A (73% to 88%) or influenza B.2 Influenza A subtypes were either H1N1 or H3N2, which are the two strains of influenza contained in the annual vaccine. Only 20% to 37% of enrolled patients had received influenza vaccination.2 Compared with placebo, baloxavir will decrease the duration of symptoms of uncomplicated PCR-confirmed influenza in adults 20 to 64 years of age by 24 to 30 hours (50 to 54 hours of

Address correspondence to Deborah R. Erlich, MD, MMedEd, at Reprints are not available from the author.

Author disclosure: No relevant financial affiliations.


show all references

1. DailyMed. Drug label information: Xofluza—baloxavir marboxil tablet, film coated. Accessed May 24, 2019.

2. 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.

3. Ebell MH, Call M, Shinholser J. Effectiveness of oseltamivir in adults: a meta-analysis of published and unpublished clinical trials. Fam Pract. 2013;30(2):125–133.

4. The Roche Group. Investor update. June 4, 2019. Accessed June 19, 2019.

5. Centers for Disease Control and Prevention. Influenza antiviral drug resistance. Accessed May 24, 2019.

6. Gubareva LV, Mishin VP, Patel MC, et al. Assessing baloxavir susceptibility of influenza viruses circulating in the United States during the 2016/17 and 2017/18 seasons. Euro Surveill. 2019;24(3).

STEPS new drug reviews cover Safety, Tolerability, Effectiveness, Price, and Simplicity. Each independent review is provided by authors who have no financial association with the drug manufacturer.

This series is coordinated by Allen F. Shaughnessy, PharmD, MMedEd, assistant medical editor.

A collection of STEPS published in AFP is available at



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