An experimental compound could be the answer in the battle against drug-resistant form of the deadly H5N1 avian influenza which is also known as bird flu, say researchers.
They believe that compound known as T-705, can be more potent and safer for treating "bird flu" than the antiviral drug best known by the trade name Tamiflu.
According to Yoshihiro Kawaoka, a University of Wisconsin-Madison virologist and the senior author it even works several days after infection.
"H5N1 virus is so pathogenic even Tamiflu doesn't protect all the infected animals," said Kawaoka.
"This compound works much better, even three days after infection."
The study conducted over mice showed that the compound was effective and safe against H5N1 virus, the highly pathogenic bird flu virus, which some scientists fear could spark a global epidemic of deadly influenza.
The compound is also effective against seasonal flu and more worrisome varieties such as the H1N1 virus, and has already been tested against circulating seasonal influenza in humans in Japan where it is on the brink of Phase III clinical trials in people.
Aside from its safety and basic efficacy, another key trait of the T-705 compound is the fact that it is effective even after an infection is acquired.
Bird flu, notes Kawaoka, is almost always diagnosed in the hospital after symptoms of the disease manifest themselves: "This compound has a chance to save people who have gone into the disease course," he added.
T-705 targets a critical viral molecule, polymerase, an enzyme that enables the virus to copy its genetic material, RNA. By disabling polymerase, the virus is unable to make new virus particles and maintain the chain of infection.
"The activity of this agent is considerably higher than Tamiflu," said Kawaoka, adding, "the compound is very specific to viral polymerase. It doesn't affect host polymerase, which is important for safety and reducing side effects."
The study appears in Proceedings of the National Academy of Sciences (PNAS).