Baloxavir Marboxil: The First Cap-Dependent Endonuclease Inhibitor for the Treatment of Influenza.

OBJECTIVE

To review the pharmacology, pharmacokinetics, clinical trials, and clinical implications of baloxavir marboxil.

DATA SOURCES

A MEDLINE search was conducted using the terms baloxavir, baloxavir marboxil, cap-dependent endonuclease inhibitor, and polymerase acidic endonuclease inhibitor. Additional data were obtained from the prescribing information and relevant guidelines.

STUDY SELECTION AND DATA EXTRACTION

All clinical trials were included.

DATA SYNTHESIS

Baloxavir marboxil exploits a new mechanism of action of inhibiting cap-dependent endonuclease. Baloxavir was shown to be superior compared with placebo and noninferior compared with oseltamivir with regard to the primary end point. Baloxavir was well tolerated in the trials. A second phase III study investigating high-risk patients was completed with positive results. However, the full article is not yet published. Relevance to Patient Care and Clinical Practice: The small amount of literature limits baloxavir's use in certain patient populations. Baloxavir offers advantages such as single-dose regimen, eliminating adherence concerns and lack of cross-resistance, making it an alternative for resistant viruses. Several uncertainties remain. Baloxavir has not been studied in hospitalized patients, patients with symptoms for >48 hours, or in combination with other antiviral agents. Furthermore, resistance to baloxavir can develop after 1 dose. Clinical studies are ongoing to evaluate baloxavir in young pediatric patients, hospitalized patients, and in combination therapy with neuraminidase inhibitors to further elucidate baloxavir's place in therapy.

CONCLUSION

Baloxavir is a new antiviral medication for the treatment of influenza. Given the new mechanism of action, baloxavir may be useful in treating patients with resistant viruses.