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Tuesday, July 01, 2003

By Anita Srikameswaran, Post-Gazette Staff Writer

Local researchers have joined an international trial of a marijuana-based drug that could limit the damage caused in traumatic brain injuries.

Dr. Jack Wilberger, chairman of neurosurgery at Allegheny General Hospital, will be leading the local arm of the study, which began here about 10 days ago.

Dexanabinol, a synthetic drug, is derived from the active agent in cannabis, or marijuana. It acts on the so-called secondary injury process, which is a chemical cascade that leads to progressive brain cell death after the initial trauma. The drug counters inflammation, works as an antioxidant and blocks the uncontrolled influx of calcium into the cells, which can kill them.

"It's different from all other drugs we've tried in head injury in that all of them were limited to one of those three mechanisms of action," Wilberger said. "None of them worked."

Dexanabinol could help because it does all those things simultaneously. The drug can be given by injection up to four hours after the injury is sustained.

Minimal side effects were seen in earlier European trials, Wilberger said. Although the drug is based on a marijuana molecule, it doesn't give patients a "high."

For the trial, head injury patients will be randomly assigned to receive the drug or a placebo. The researchers will compare mortality rates for the two groups, as well as recovery levels.

About 15 to 20 local residents could number among the anticipated 250 American participants. About 1,500 patients ultimately will be enrolled in the trial, which includes both U.S. and European hospitals, Wilberger said.

Studies conducted in Israel found that three months after injury 42 percent of patients who took dexanabinol had good neurological recovery compared to 17 percent of those taking a placebo.

Dexanabinol's properties were discovered in the late 1980s by researchers at Israel's Tel Aviv University. The drug is being made by Pharmos Corporation, based in Rehovot, Israel.

According to the U.S. Centers for Disease Control and Prevention, 1.5 million people sustain a brain injury each year. As a result, about 50,000 people die and up to 90,000 are left with a longterm or lifelong disability.

After brain injury, "few people come back normal, to the way they were before," Wilberger noted. Animal experiments showed that dexanabinol markedly improved recovery, but in that setting the drug was given immediately.