Cancer drug may fight smallpox, study suggests

[Guest guest]

Hi Group,

Cheryl-Anne mentioned the substance of this article in a previous

post, but this one just hit the newswires in California...

Warm Regards,

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Cancer drug may fight smallpox, study suggests

Mon Jun 27, 1:13 PM ET

WASHINGTON (Reuters) - A cancer pill noted for its effectiveness in

stopping leukemia in some patients can also help delay the deadliest

effects of a pox virus in mice -- offering the prospect of using

similar drugs to treat or prevent smallpox, scientists said on Monday.

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Tests of Gleevec, Swiss drug giant Novartis AG's successful leukemia

pill, showed it could save the lives of mice infected with vaccinia --

a close relative of smallpox.

The drug, known generically as imatinib or STI-571, also prevented

infection in the mice and slowed the spread of the virus in the body

when given after infection.

" We propose the use of STI-571, a drug developed to treat cancer

without substantial side effects, as a therapeutic for infections

caused by pox viruses, " the researchers write in this week's issue of

the journal Nature Medicine.

Other drugs being developed in the same class may be even more useful

against not only smallpox but other germs that infect cells in similar

ways, the researchers, led by Kalman of Emory University School

of Medicine in Atlanta, said.

Smallpox, caused by a virus called variola, was declared eliminated in

1980 after a global vaccination campaign. It no longer exists in

nature, but experts fear terrorists or governments could use samples

to launch biological attacks.

Once a dreaded disease with a fatality rate of 30 percent, smallpox

was wiped out by using the first-ever vaccine -- based on the related

vaccinia virus.

With the risk of biological attacks, researchers are working on a

better, more modern vaccine and also exploring treatments for both

smallpox and the side-effects of the existing smallpox vaccine, which

is crude.

Kalman's team discovered that the smallpox virus uses an enzyme called

tyrosine kinase to move from cell to cell.

New cancer drugs target this enzyme, which is also used by cancer

cells to spread.

So Kalman's team gave the drug or a placebo to mice and then infected

them with vaccinia. Only about 30 percent of the mice treated with

placebo lived, compared to 100 percent of Gleevec-treated mice.

Pfizer has a drug similar to Gleevec in development. Known only by its

experimental name PD-166326, it may be even more potent, experts say.

" Drugs such as PD-166326 may prove useful once the virus has

disseminated, a prospect we are currently testing, " Kalman's team wrote.

It may also be possible to use Gleevec or similar drugs along with

Gilead Sciences Inc's cidofovir, an antiviral drug that has also been

shown to work against smallpox.

The approach may work against other viruses and some bacteria, the

researchers said.

For instance, when

E. coli takes on a dangerous form, it uses tyrosine kinases, as does a

virus called polyoma, which has been associated with cancer.

" The approach of fighting disease by targeting drugs to cellular

molecules rather than to disease agents themselves may be applicable

to a wide variety of pathogenic microorganisms, " Kalman said in a

statement.