Baloxavir: A Novel Antiviral Agent in the Treatment of Influenza

Baloxavir marboxil (formerly S-033188) is a prodrug of baloxavir acid (S-033447) and inhibits cap-dependent endonuclease, an essential protein involved in the initiation of viral transcription by cleaving capped mRNA bound to PB2. Its adverse event profile is comparable to oseltamivir but is still vulnerable to resistance. The single-dose baloxavir marboxil is an appealing antiviral regimen for the treatment of influenza among outpatients when compared with longer, twice-daily regimens of oral and inhaled neuraminidase inhibitors. This review focuses on the mode of action, antiviral activity, pharmacokinetics, clinical indications, and safety profiles of this drug. Considerations for formulary addition and its place in therapy are also discussed.