New antivirus effective against H5N1 flu
21 April 2010
A new compound is highly effective against the pathogenic H5N1
avian influenza virus, including some drug-resistant strains, according
to new research led by a University of Wisconsin-Madison virologist.
The work, published in PLoS Pathogens on Feb 26,
suggests that the compound CS-8958 is a promising alternative
antiviral for prevention and treatment of bird flu.
Antiviral drugs are a primary countermeasure against human
influenza viruses, including the highly pathogenic H5N1 avian
influenza virus, which causes bird flu. Emerging strains resistant
to existing drugs, particularly oseltamivir (Tamiflu), pose a threat
and make the development of alternate antivirals a pressing public
health issue, says Yoshihiro Kawaoka, a professor of pathobiological
sciences at the UW-Madison School of Veterinary Medicine and senior
author of the new study.
Kawaoka and a group of researchers from Japan, Vietnam, and
Indonesia tested a novel neuraminidase inhibitor R-125489 and its
prodrug CS-8958, which had previously shown potent activity against
seasonal influenza viruses in laboratory animals.
Working with mice, the researchers found that a single intranasal
dose of CS-8958 given two hours after infection with H5N1 influenza
virus resulted in a higher survival rate and lower virus levels than
a standard five-day course of oseltamivir. CS-8958 was also
effective against highly pathogenic and oseltamivir-resistant
strains of H5N1 virus.
In addition to its therapeutic use, CS-8958 also protected mice
against lethal H5N1 infection when given seven days before infection
with the virus.
“This compound requires only a single administration for both
treatment and prophylaxis. Such prophylaxis would be highly
desirable for seasonal influenza as well as a potential pandemic
situation,” says Kawaoka.
Although follow-up studies will be needed to confirm the
applicability of the findings to humans, “CS-8958 is highly
effective for the treatment and prophylaxis of infection with H5N1
influenza viruses, including oseltamivir-resistant mutants,” the