Advanced X-ray technology has helped scientists spot a new target that drug designers might use to attack the dreaded bird flu virus.
Though a new drug would still be years off, the new research being published Thursday offers hope of a fresh way to fight a disease that health experts fear could one day evolve into a deadly human flu pandemic.
"This gives us a new target that we didn't know we had before," said Dr. Michael Perdue, a flu expert at the World Health Organization, who had no role in the study.
Researchers used advanced X-ray technology to provide an "atomic picture" of the atoms and molecules that comprise one of the two surface proteins in the H5N1 virus.
Neuraminidase — the "N" in H5N1 — is the protein in bird flu that allows the virus to spread to other cells in the body. Drugs currently used to treat bird flu are based on other neuraminidase models that are not specific to H5N1.
By identifying H5N1's unique blueprint, researchers may one day be able to use drugs that home in on the strain that has killed 139 people in the past three years.
New drugs targeting H5N1 could potentially be used in combination with the current leading bird flu medication Tamiflu to reduce the risk of the virus mutating into a resistant form, said John Skehel, lead author of the paper appearing in the journal Nature.
Drug combinations can reduce the risk of a virus becoming resistant to one drug, a lesson learned in the fight against AIDS, noted Skehel, director of the National Institute for Medical Research in London.
Research into new flu drugs has traditionally focused on the neuraminidase protein because flu's other surface protein — hemagglutinin, the "H" in H5N1 — has proven harder to attack.
To date, Tamiflu, which was developed to treat human flu, is the only drug shown in lab studies to be somewhat effective against H5N1. However, there have been isolated instances of strains resistant to Tamiflu.
Experts agree on the importance of having more drugs in the arsenal to fight bird flu.
"Right now, our options are really quite limited," said Dr. Fred Hayden, an antivirals and influenza expert at the WHO. "We're really down to Tamiflu and Relenza, so there is a need for an alternative."
Though the timeline for producing a new drug usually takes between three to five years, it could potentially be shortened as countries accelerate their pandemic preparedness plans.
"Since drug companies have already attacked neuraminidase before, they should already have a lot of information on how to build compounds that would work in attacking it," said Perdue, who cautioned that the process of conducting clinical trials in humans could still take years.