[Ip-health] Wall Street Journal: Generics Work Against Bird Flu

[Thiru Balasubramaniam]

http://online.wsj.com/article/SB114728376035549154.html

Generics Work Against Bird Flu

By *NICHOLAS ZAMISKA*
May 11, 2006; Page D3

A pair of generic drugs that are plentiful and cheaper than Tamiflu
could gain further credibility as a bird-flu treatment because of a
study in a prominent U.S. scientific journal.

The study, which will appear in a coming issue of the Journal of
Infectious Diseases, reports that the vast majority of strains of the
deadly avian-influenza virus, H5N1, found in China and Indonesia would
respond to the drugs, known as amantadine and rimantadine.

The research further erodes the conventional wisdom that these older
drugs are useless against bird flu in humans. It raises the possibility
that they may be employed selectively alongside Tamiflu, made by the
Swiss drug company *Roche Holding *AG, to treat victims of the virus and
to bolster government stockpiles of antiviral drugs.

"Amantadine appears to retain the potential to be useful in an H5N1
pandemic in the absence of a vaccine, as a prophylactic agent and as a
component of combination antiviral therapy," the study says.

In March, an official of the World Health Organization said that of the
approximately 130 strains of the H5N1 form of the virus whose sequences
the WHO had analyzed, about a quarter were sensitive to the older drugs.
Roche has said that all the strains of H5N1 that have been examined so
far would be susceptible to Tamiflu.

Early human cases of bird flu in Southeast Asia "gave people a
conception that H5N1 is probably resistant to amantadine," Honglin Chen,
a virologist at the University of Hong Kong and an author of the study,
said in an interview. "But if you analyze the viruses from China,
Indonesia and even the virus circulating in Europe and Africa, the
viruses are sensitive."

The study analyzed 638 H5N1 viruses from a handful of countries in Asia
-- 39 viruses from humans and 599 from birds. While more than 95% of
virus isolates from Vietnam and Thailand had mutations that would make
them resistant to the older drugs, the authors found, only 6.3% of those
from Indonesia and 8.9% from China did. Those results dovetail with
recent findings that the virus has evolved into distinct subgroups.

"Although amantadine-resistant H5N1 viruses are present in Asia, their
distribution appears to be largely limited to Thailand, Vietnam, and
Cambodia," wrote the authors, who reported no conflicts of interest in
preparing the study.

Since late 2003, at least 207 people have been infected with bird flu,
according to cases confirmed by WHO. Most, if not all, of those people
fell ill after coming into contact with infected birds. Of those cases,
115 have been fatal. But scientists fear that the virus could quickly
mutate into a form that passes easily among humans, igniting a pandemic
that could kill millions world-wide.

*Write to *Nicholas Zamiska at nicholas.zamiska@wsj.com
<mailto:nicholas.zamiska@wsj.com>^6