Currently Enrolling Trials
Xofluza (baloxavir marboxil) is an antiviral drug with activity against the influenza virus.
Xofluza is specifically 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.
Xofluza is also indicated for the post-exposure prevention of influenza for patients 12 years of age and older after contact with an individual who has the flu.
Xofluza is supplied as a tablet for oral administration, as well as granules for mixing in water. A single dose of Xofluza should be administered orally within 48 hours of symptom onset with or without food. Avoid co-administration of Xofluza with dairy products, calcium-fortified beverages, polyvalent cation-containing laxatives, antacids, or oral supplements (e.g., calcium, iron, magnesium, selenium, or zinc). The dose of Xofluza depends on weight, as follows:
• Patient Body Weight: 40 kg to less than 80 kg, the recommended dose is a single dose of 40 mg
• Patient Body Weight: At least 80 kg, the recommended dose is a single dose of 80 mg
The FDA approval of Xofluza was based on two randomized controlled clinical trials of 1,832 patients where participants were assigned to receive either Xofluza, a placebo, or another antiviral flu treatment (oseltamivir) within 48 hours of experiencing flu symptoms. The primary endpoint of both trials, time to alleviation of symptoms, was defined as the time when all seven symptoms (cough, sore throat, nasal congestion, headache, feverishness, myalgia, and fatigue) had been assessed by the subject as none or mild for a duration of at least 21.5 hours. In both trials, Xofluza treatment at the recommended dose resulted in a statistically significant shorter time to alleviation of symptoms compared with placebo in the primary efficacy population. In Trial 2, there was no difference in the time to alleviation of symptoms between subjects who received Xofluza (54 hours) and those who received oseltamivir (54 hours). For adolescent subjects (12 to 17 years of age) in Trial 2, the median time to alleviation of symptoms for subjects who received Xofluza was 54 hours compared to 93 hours in the placebo arm.
The FDA approval of Xofluza for post-flu exposure prevention was based on one randomized, double-blind, controlled trial in which 607 subjects, 12 years of age and older who were exposed to a person with influenza in their household, received either a single dose of Xofluza or a single dose of a placebo. Of these 607 subjects, 303 received Xofluza and 304 received the placebo. The trial's primary endpoint was the proportion of subjects who were infected with influenza virus and presented with fever and at least one respiratory symptom from day 1 to day 10. Of those who received Xofluza, 1% of subjects met these criteria, compared to 13% of subjects who received a placebo for the clinical trial.
Adverse effects associated with the use of Xofluza may include, but are not limited to, the following:
Mechanism of Action
Baloxavir marboxil is a prodrug that is converted by hydrolysis to baloxavir, the active form that exerts anti-influenza virus activity. Baloxavir inhibits the endonuclease activity of the polymerase acidic (PA) protein, an influenza virus-specific enzyme in the viral RNA polymerase complex required for viral gene transcription, resulting in inhibition of influenza virus replication. The 50% inhibitory concentration (IC50) of baloxavir was 1.4 to 3.1 nM (n=4) for influenza A viruses and 4.5 to 8.9 nM (n=3) for influenza B viruses in a PA endonuclease assay. Viruses with reduced susceptibility to baloxavir have amino acid substitutions in the PA protein.
For additional information regarding Xofluza or acute uncomplicated influenza, please visit the Xofluza website.