"No reason why [it wouldn't work]," he says. "We're big primates."

HOW IT WORKS


Although low doses of radiation can damage cellular DNA, which can lead to cancer after many years, high doses of radiation kill directly, usually by destroying bone marrow tissue containing stem cells required to create blood cells and by breaking down the lining of the intestines.

"Our blood cannot reconstitute itself [after high-dose radiation exposure]. Where there's trauma to stem cells, you don't have enough progenitors [for blood]. Thirty days later, you don't have functional blood," says Fonstein.

These lethal effects happen for two molecular reasons, Fontesin says. One is that radiation causes stem cell precursors to blood to commit cellular suicide, a process known as apoptosis. The second action is the release of free radicals, cell-killers that don't get scavenged at the rates they should and which "toxify our body," Fonstein says.

The Protectan works, according to Fonstein, by blocking apoptosis in healthy cells while also interacting with cell surfaces and activating enzymes to help sweep up the toxifying free radicals.

MORE THAN ARS

Because of these actions, Cleveland hopes the drug will have more applications than for just ARS.

It could be used to protect against side effects from radiotherapy, most obviously, as it would spare healthy cells from damage while leaving tumors at radiation's mercy. In most cancer cells, Fonstein explains, the "apoptotic machinery" is broken so they cannot be protected from the drug's actions.

But the drug could protect from more than just radiation. It could also help limit chemotherapy's side effects and even diminish damage caused by ischemia, such as in heart attacks and stroke.

In ischemias, Fonstein explains, much of the damage to the body comes from bursts of free radicals from dying cells.

"The reasons why we suffer from radiation or heart attack on the basic molecular level are almost identical, because in both cases you have an explosion of free radicals that push cells into suicidal death."

Of course, these healthful actions carry side effects, mostly moderate flu-like symptoms, such as light fever. "The drug induces massive re-building of your blood," says Fonstein. Because of the side effects, the drug is not intended for chronic use in populations with daily slightly elevated radiation exposures, like airline pilots, but only in response to one-time extreme radiation doses.

FUTURE APPROVALS

Right now, Fonstein says the company only plans on getting trials off the ground for radiation sickness and for the drug's supportive role in cancer treatment, for both radiation and chemotherapy, with Phase 1 or Phase 2 trials expected to begin probably this year.

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