December 1, 2005

FDS approves West Nile virus test for donors

By Susan Heavey

WASHINGTON (Reuters) - A test to screen blood, organ and
tissue donors for the West Nile virus won U.S. approval after
two years of testing in the nation's blood banks, Food and Drug
Administration officials said on Thursday.

The Procleix WNV Assay was developed by Gen-Probe Inc. and
marketed by Chiron Corp.

West Nile virus is most-often transmitted by mosquitoes,
but there have been 30 documented cases of people who most
likely got the illness from a blood transfusion, including nine
who died, the FDA said.

The virus, discovered in the United States in 1999, has led
to 762 deaths and about 20,000 diagnosed patients since 2002,
the agency said.

Another test already exists to help doctors diagnose the
disease, but it needs to be used in conjunction with additional
laboratory tests. Procleix is the first U.S.-approved test for
blood banks and facilities working with donors because it can
stand alone.

West Nile virus can trigger fever, headache, muscle ache
and rashes and, in some cases, swelling of the brain and
surrounding areas.

The new test would be run on samples of blood taken from a
donor or cadaver at the time of donation, FDA spokeswoman Julie
Zawisza said. Donated organs, blood or tissue would be held
until test results were available.

Blood banks began experimenting with such tests in June
2003, and have caught about 1,600 infected donations, the FDA

Chiron spokesman John Gallagher said Chiron and Gen-Probe
controlled about 80 percent of the blood donation screening
market during the last two years and planned to keep that edge
with their new approval.

A test by Roche unit Roche Molecular Systems, Inc. that is
similar to the Procleix test is still being tested. FDA's
Zawisza said the agency would allow Roche to use the test
experimentally until it gathers enough clinical information to
seek approval.

Representatives for Roche and Gen-Probe did not immediately
return calls seeking comment.

Gen-Probe stock closed up 6.5 percent, or $3.01, at $49.18
a share, while Chiron shares rose one cent to $44.31, both on
the Nasdaq.