Baloxavir marboxil: a novel cap-dependent endonuclease (CEN) inhibitor for the treatment of acute uncomplicated influenza

Baloxavir marboxil is a newly approved antiviral agent with activity against influenza via a novel mechanism of action of inhibition of cap-dependent endonuclease (CEN). The novel agent was approved in October of 2018 in the United States for the treatment of acute uncomplicated influenza A and B in patients aged 12 years or older. Baloxavir is given as a single weight-based dose of 40 mg orally once for patients weighing less than 80 kg and 80 mg orally once for those weighing 80 kg or more within 48 hours of symptom onset. In comparison with current therapy, baloxavir is as effective in decreasing time to symptom alleviation as the drug of choice, oseltamivir, and significantly reduces viral load 1 day after treatment compared with placebo and oseltamivir. In safety analyses baloxavir was well tolerated with only mild adverse events reported (nausea, headache, diarrhea, bronchitis, nasopharyngitis), thus providing a safe and reliable alternative option to current therapy for acute uncomplicated influenza. Further studies are being conducted to evaluate the use of baloxavir in additional patient populations including pediatric patients less than 12 years of age and patients who are at high risk of complications related to influenza.