WEDNESDAY, Feb. 8, 2006 (HealthDay News) -- A new drug for the emergency treatment of stroke provided a slight but significant improvement over existing therapy in an international study designed to be a step toward bringing the medication to market.
"The effect is about a 4 percent difference in the likelihood of fully recovering from the stroke," said Dr. James Grotta, a professor of neurology at the University of Texas Medical School at Houston.
"That is a fairly modest effect, but the effect on the large population of people who have strokes could be significant," added Grotta, a member of the team reporting the study results in the Feb. 9 issue of the New England Journal of Medicine.
There are two reasons for the excitement about the new drug, currently designated NXY-059. First, doctors are desperate for an alternative to the only available drug, tPA, which has its flaws. It must be given within three hours after a stroke occurs, so only about 30 percent of patients get to use it, Grotta estimated. And it has side effects that limit its usefulness.
By contrast, NXY-059 was given up to six hours after a stroke occurred in the trial, so that many more stroke patients were eligible to receive it. "The eventual impact is that a larger percentage of stroke patients are likely to use this treatment," Grotta said. And it has "few, if any, side effects," he added.
Also, NXY-059 acts in a far different way than tPA. Both are intended for ischemic strokes, which occur when a clot blocks a brain artery. About 80 percent of strokes are ischemic; the other 20 percent are caused by a burst blood vessel.
While tPA acts by dissolving the clot to restore blood flow, NXY-059 protects neurons from damage by trapping the free radicals, which are inflammatory cells that are generated in a blocked artery. "One mechanism by which cells die is inflammation caused by generation of free radicals," Grotta explained.
The search for such a neuroprotective drug has been going on for more than a decade, said Dr. Gregory J. del Zoppo, a professor of neurology at the Scripps Research Foundation in La Jolla, Calif., who has been active in the field and wrote an accompanying commentary in the journal. Until now, that search has been fruitless.
"There have been a number of attempts to reduce free radical damage," he said. "Few of the compounds that have been investigated had the capacity to be given to patients. Many of these compounds have anesthetic effects, and they may have cardiac effects."
The question now is "after so many failures, why should this neuroprotectant succeed?" del Zoppo said. The answer, it appears, is that it doesn't act on neurons alone but also on the cells that surround the neurons, he explained.
That finding opens a new avenue of research, del Zoppo said. "It is really exciting because it brings increased attention to this aspect of protection," he said. "This modest effect is potentially a signal. It is not the answer to stroke, but it certainly opens up possibilities in a field that has not had much success in the past 10 years."
As for the practical matter of marketing the drug, that depends on the outcome of a large-scale study, to include 2,400 patients, whose results are expected early in 2007, said James McDermott, executive director for neuroscience clinical development at AstraZeneca, which owns rights to NXY-059.
"We would anticipate filing [for approval by the U.S. Food and Drug Administration] in the first half of 2007," McDermott said. While the speed of FDA action is unpredictable, "we would anticipate a launch in the first half of 2008," he said. A brand name for the drug has not been chosen, McDermott added.
More information
For more on tPA, head to the American Heart Association.
