Oct. 5, 2004 (Atlanta) -- A close relative of the performance-boosting suppl
Oct. 5, 2004 (Atlanta) -- A close relative of the performance-boosting supplement DHEA may be able to combat radiation from a "dirty bomb," Researchers say.
Known as Neumune, "this and similar drugs could protect us from the potentially fatal radiation sickness associated with a nuclear attack as well as from some elements of a dirty bomb," says Dwight Stickney, MD, vice president of medical affairs at Hollis-Eden Pharmaceuticals, Inc., the San Diego-based company developing the novel agent. "Casualties would be greatly reduced."
Dirty bombs are explosive devices that don't pack the punch of nuclear bombs, but can spread lethal doses of radiation to surrounding areas.
Specifically, Neumune protects our infection-fighting bone marrow, known to be particularly hard hit in a dirty bomb or nuclear attack, he tells WebMD.
Speaking here at the annual meeting of the American Society for Therapeutic Radiology and Oncology, Stickney notes that researchers in a recent scientific article in the BMJ predict that if a small and crude nuclear device were detonated in New York City, approximately 50,000 people would die from the initial blast. But another 200,000 would die shortly thereafter from severe bone marrow damage, and an additional 700,000 would be at risk because of radiation sickness resulting from bone marrow damage.
"The primary cause of death from radiation is a severe depletion of bone marrow cells," Stickney says.
Enter Neumune -- a close relative of performance-enhancing DHEA, or dehyroepiandrosterone. It is a hormone naturally made by the adrenal glands.
90% Survival Rate With Neumune
In studies in monkeys, Neumune protected all three elements of the bone marrow: the white blood cells that fight infection, the platelets that help blood to clot, and the red blood cells that transport oxygen throughout the body, Stickney reports. "No other single compound has ever done that before."
In the studies, 30 primates were exposed to potentially fatal doses of radiation. "The doses we gave were such that you would expect 50% of the animals to die," Stickney says, "a good simulation of what would happen [to humans] in a terrorist nuclear explosion."
Ten of the animals received no treatment, while 10 received placebo and 10 received injections of Neumune beginning several hours after radiation exposure. The study showed that 90% of the Neumune-treated macaques survived, compared with only 55% of those that received either placebo or no treatment.
The drug had few side effects, with only minor swelling that resolved over time, Stickney says.
"We're very excited," he adds. "This is the first time a drug has safely stimulated all three aspects of the bone marrow while also showing an improvement in survival."
Since it would be unethical to subject humans to the high doses of radiation necessary to test Neumune, the company will be trying to gain FDA approval under its so-called "animal rule" for countermeasures to weapons of mass destruction. In such cases, study results in animals are used as a surrogate for what could happen in humans following a dirty bomb attack.
"The FDA has indicated our model is acceptable," Stickney says. So the next step is to determine the minimum dose needed to improve survival, followed by further studies in nonhuman primates. He predicts everything could be done by next year.
Thomas MacVittie, PhD, professor in the departments of radiation oncology and pathology at the University of Maryland Cancer Center in Baltimore, and one of the nation's top experts on radiation sickness, is equally excited.
"I give [Stickney's team] a lot of credit," he tells WebMD. "They're asking the hard questions and have shown that the drug will modify lethality."
MacVittie agrees that nonhuman primates offer an "excellent model" for studying human radiation exposure and its treatment following a possible dirty bomb attack. "I think we'll need to see tests in larger numbers of animals before the drug is approved, but everything is moving in the right direction."
