San Diego scientists develop promising smallpox treatment

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KGTV TheSanDiegoChannel.com | San Diego Daily Transcript

Wednesday March 20 08:50 PM EST

Two local scientists develop promising smallpox treatment

Two San Diego scientists have developed a promising oral treatment for

smallpox in case the deadly virus is used in a bio-terrorism attack.

The drug is 100 times more potent than the current therapy, which is less

effective because it's injected intravenously, said lead scientists Karl

Hostetler and Beadle. Both men are researchers for the Veterans

Affairs San Diego Healthcare System and professors at the University of

California, San Diego.

UCSD already is negotiating with private companies to develop the drug

commercially, said Sue Pondrom, a spokesperson for the university.

Pondrom said the talks were " on-going, " but would not say what companies

were involved.

So far, the new drug prevents death in mice infected with a similar virus

and in lab cell cultures, the scientists said. The drug must be tested on

other animals and humans before it is available.

The development of an oral vaccine for smallpox is of great interest to the

U.S. government. Experts have predicted that smallpox could be used in a

bio-terror attack.

And, according to the Centers for Disease Control and Prevention (news - web

sites), the government's supply of the smallpox vaccine has extreme side

effects such as brain inflammation.

Smallpox is an easily transferable virus that kills 30 percent of the people

that contract it, according to the World Health Organization (news - web

sites).

" This drug has been more effective at inhibiting virus replication in the

lungs -- which is the first target -- than any other drug that we've looked

at. It completely eliminated virus growth, so we're pretty excited about

it, " said Huggins, chief of viral therapeutics at the U.S. Army Medical

Research Institute of Infectious Diseases, which is evaluating the drug.

Laughlin of the U.S. National Institute of Allergy and Infectious

Diseases (news - web sites), called the initial result " promising. "

" But the new drug is a long way from being demonstrated sufficiently safe

and effective for human use. The additional studies needed are being

undertaken as a highest priority, " said Laughlin, chief of virology in the

division of microbiology and infectious diseases.

Hostetler and Beadle have been working on the drug since 1999. Their work

was financed by a $1.6 million grant from the U.S. Army, and supplemental

funding from the National Institute of Allergy and Infectious Diseases, the

National Eye Institute and the Veterans Affairs San Diego Healthcare

System -- where both men work.

A team of scientists that included Hostetler, Beadle, Huggins and staff from

the University of Alabama developed the drug, called

hexadecyloxypropyl-cidofovir, or HDP-CDV.

Hostetler and Beadle presented the group's findings at the International

Conference on Antiviral Research on Wednesday in Prague, Czech Republic.

Hostetler believes HDP-CDV is superior to the current alternative, called

cidofovir, because the new drug is easier to disperse to the general

population. HDP-CDV is a modified form of cidofovir, which prevents the

replication of the smallpox virus.

" Cidofovir's drawback is poor oral bio-availability. It can only be given

intravenously, " Hostetler said. " If you've got thousands of people exposed

to smallpox, a drug that needs to be injected would be difficult to use

widely. "

Unlike cidofovir, human cells absorb HDP-CDV more readily, making it a 100

times more effective. Smallpox is best known as an air-borne virus.

Furthermore, the new drug blocks the activity of variola, the virus that

causes smallpox.

In lab tests performed by the Army, HDP-CDV also prevented mice with cowpox

from dying from the infection and reduced virus levels in the lungs of

infected animals to nearly undetectable levels.

" Given preventatively at the appropriate dose we found no evidence of the

animals getting sick at all, " said the Army's Huggins.

" Once we've understood the drug, we can then move on to producing monkeypox

disease in monkeys -- and that truly does look like the human disease, " he

said. " Then, once we've worked out what the correct dose is, we will go on

to test it against smallpox in monkeys. "

In earlier experiments, Huggins found that the parent drug, cidofovir,

prevented the death of primates infected with monkeypox, even after symptoms

had appeared.

It will be a year or two before the pill can be tested for safety on humans,

Huggins estimated.

The Associated Press contributed to this report.