[Baloxavir marboxil: a potent cap-dependent endonuclease inhibitor of influenza viruses].

Baloxavir marboxil (5-hydroxy-4-pyridone-3-carboxyl acid) is a new antiviral drug with special efficacy on influenza viruses that acts by inhibiting the cap-dependent endonuclease required for its replication. It is the first representative of the so-called inhibitors of influenza-like PB2. It has shown efficacy against influenza viruses A and B and most strains of animal origin (avian flu). Clinical trials conducted in healthy patients between 12 and 64 years without pathologies and not hospitalized (mild flu) have shown a reduction in the duration of symptoms similar to that obtained by oseltamivir. However, baloxavir is a much more potent inhibitor of viral replication than this drug. It has been shown as a safe and well tolerated drug. A single dose of 40-80 mg is administered the first 48 hours after onset of symptoms. In these trials, strains with moderate sensitivity (PA / I38T mutants) were detected in 2.2% of influenza A (H1N1) pdm09 and in 9.7% of influenza A (H3N2). Although these data could be a good drug to treat mild or moderate influenza, requiring trials in severe influenza and patients with chronic diseases to establish their true clinical utility.