Flu drug 'shows promise' in overcoming resistance

Drug works by blocking an enzyme on the surface of the flu virus A new type of flu drug that can stop resistant strains from developing may be available soon, according to US researchers. A team of scientists from Canada, the UK and Australia have developed a compound that permanently blocks a key enzyme on the surface of the flu virus, stopping it from spreading to other cells.
This enzyme is responsible for severing the connection between the flu virus and human cell so it can move on and infect other cells.
A new class of drugs, called DFSAs, permanently bind to the enzyme, blocking its action and stopping it from spreading further, the journal Science reported.
DFSAs work in such a way that the flu virus cannot evolve to be resistant to the drug without rendering itself useless.
Researchers, who tested the drug on mice, found that it was effective against strains which were resistant to the two flu antivirals, Relenza and Tamiflu, currently on the market.
Study leader Prof Steve Withers from the University of British Columbia said: "Our drug agent uses the same approach as current flu treatments - by preventing neuraminidase from cutting its ties with the infected cell.
"But our agent latches onto this enzyme like a broken key, stuck in a lock, rendering it useless," he added.
Co-author Dr Andrew Watts from the University of Bath said: "Our drug can work even better in drug resistant strains than in natural viruses emphasising that it is working through a totally different mechanism."
He added that realistically it would be six to seven years before the drug came to market.
The World Health Organisation estimates that influenza affects three to five million people every year.
Overuse of existing flu drugs has made resistance an increasing problem, said the journal Science.
The more exposure the flu virus has to the drugs the more chance it has of working out how to evade their effects. Yet flu drugs are the only weapon available for treating patients during a pandemic, where it can often take months to develop a vaccine.