Radiation sickness drug could save thousands

[modsafety@GTNET.GOV.UK]

New Scientist reports



Radiation sickness drug could save thousands

15:02 20 May 03



http://www.newscientist.com/news/news.jsp?id=ns99993745



An experimental drug that protects against radiation sickness could save

tens of thousands of lives in the aftermath of a nuclear attack by

terrorists, claim the scientists developing the treatment.

The detonation of a "dirty bomb", an attack on a nuclear power plant or even

a nuclear accident would release radiation into the atmosphere. The

short-term effect of the release would very likely cause more deaths than

the blast itself.

The drug, being developed by US military researchers and Hollis-Eden

Pharmaceuticals, San Diego, tackles a key short term effect of radiation

sickness - reduced immune system function.

Test results in animals so far have been promising and researchers suggest

HE2100 may be available for humans by early 2005. "It may offer a

cost-effective treatment that could significantly improve the chance of

survival," says Dwight Stickney, a radiation oncologist and medical director

at Hollis-Eden.

"If the drug is non-toxic in humans, then it could be very useful," agrees

Bill McBride, a radiation oncologist at the University of California, Los

Angeles. And unlike previous potential radiation sickness drugs, HE2100

appears effective when taken after exposure, as well as before, he adds.



Stockpiled locally

Chris Reading, head of scientific development at Hollis-Eden, says HE2100

could be stockpiled locally and distributed immediately following an attack.

It could also be given ahead of time to emergency services or military

personnel sent into contaminated areas.

The drug works counteracting the destruction of bone marrow that follows

radiation exposure. Bone marrow is vital for manufacturing white blood

cells, the body's first line of defence against infections.

In particular, special infection-fighting cells called neutrophils can be

wiped out and most of the fatalities in the weeks following a dirty bomb

blast would die from common common infections such as influenza.

Reading told New Scientist that HE2100 acts on the earliest type of stem

cells in the bone marrow called haemopoeitic cells, stimulating the

production of neutrophils and blood platelets.



Phenomenal findings

In experiments led by Mark Whitnall, at the Armed Forces Radiobiology

Research Institute in Bethesda, Maryland, every mouse given HE2100 before

radiation exposure survived, while every mouse in the control group died.



Other tests involved giving HE2100 to non-human primates two to four hours

after radiation exposure. The animals receiving the drug exhibited severe

neutropenia on only nine per cent of days in the month after exposure,

compared to half of the primates not given the drug.



The drug has shown no side effects in primates, leading Reading to be

confident that it will be safe in humans. It would be unethical to expose

humans to radiation in a clinical trial, so the US Food and Drug

Administration allows a drug to be approved if its efficacy is shown in

animals and its safety demonstrated in humans. A larger efficacy trial is

planned for later in 2003, says Reading.



But, even if successful, HE2100 will not protect against all effects of

radiation sickness. For example, high levels of radiation can cause fatal

damage to the lungs or brain. HE2100's effectiveness may therefore depend on

a person's distance from "ground zero".

It is also unlikely to protect against long-term effects like cancer. But,

says McBride, radiation-induced cancers would be less of a priority in a

terrorist situation than protecting individuals exposed to high doses.

Shaoni Bhattacharya







=============================

Fred Dawson



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