For the first time in nearly 20 years there is a new class of antiviral drug for 
influenza. The latest approved antiviral is baloxavir marboxil (trade name, 
Xofluza) which targets the endonuclease function of the viral PA polymerase 
subunit and prevents the transcription of viral mRNA. The most promising aspect 
of this new drug is its pharmacology which allows for effective treatment of 
influenza A or B virus infection with just a single dose. A clinical trial 
showed greater reductions in viral loads with baloxavir marboxil treatment 
compared with oseltamivir, although no difference in the time to alleviation of 
symptoms between these two drugs. With this new class of influenza drug comes 
exciting prospects for combination therapy with the neuraminidase inhibitors 
which may help to abate concerns about the development of resistance.