As winter draws near, the risk of catching influenza heightens. To help alleviate symptoms, an infectious disease expert from the University of Alberta has done a study on a new class of antiviral drugs.
In a randomized double-blind controlled trial, 1,064 American and Japanese patients with mostly influenza A but also influenza B strains were given a single dose of baloxavir marboxil (Xofluza). They experienced symptom relief about 24 hours sooner than those who had no treatment remarks Nelson Lee, a professor in the U of A’s Faculty of Medicine & Dentistry and a member of the Baloxavir Marboxil Investigators Group.
“The drug also showed greater reduction in the total virus load compared with an existing commonly used flu treatment, oseltamivir (brand name Tamiflu), after one day of initiation,” says Lee, co-author of the study published in the New England Journal of Medicine. “In other words, we think based on the results of this study, the antiviral action of baloxavir is superior to that of oseltamivir. It shortens the duration of virus replication and clears it up quicker.”
The baloxavir findings are vital for those more at risk – children and seniors – due to in the ineffectively of current drugs, including oseltamivir, either aren’t effective in severe flu or some influenza strains are building resistance to them.
Oseltamivir, which belongs to a class of drugs called neuraminidase inhibitors, works by preventing the virus from releasing and spreading from one to cell to another.
“Whereas baloxavir, which belongs to the new treatment class of polymerase inhibitors, targets and shuts down the enzyme that allows for replication in the first place,” says Lee. “Because baloxavir acts on a different target of the virus, those viruses that are developing resistance to oseltamivir should be susceptible to this new agent.”
It is the first kind of drug with a proposed new mechanism of action to treat flu in 20 years.
“Although most influenza viruses today remain treatable by oseltamivir,” adds Lee, “there are cases where drug-resistant virus outbreaks continue to happen that are not treatable. Luckily, we have not had a major drug-resistant virus outbreak in the past decade, but we desperately need new classes of medications to treat the flu.”
According to Alberta Health Services, Albertans experienced 9,000 laboratory-confirmed influenza infections in 2017. Of those, 3,000 of which had complications that required hospitalization, and 234 involved intensive care admissions.
“Influenza is an important, potentially fatal disease,” says Lee. “In most patients, it will cause mild upper respiratory infections, from which they can recover in several days. In some patients, especially those with underlying medical conditions, older adults or young children, infection can be severe and cause complications like pneumonia and effect other organs. A substantial number of these people will die.”
In the next two to three years additional studies will be ongoing to examine whether baloxavir can reduce flu complications and hospitalizations and whether it could be useful for treating severe influenza infections and reducing influenza transmission.