Ancrod Ineffective for Stroke Beyond Three-Hour Window

Drug derived from snake venom associated with higher mortality, hemorrhage when given within six hours

WEDNESDAY, Nov. 29 (HealthDay News) -- Previous studies have found that ancrod, a drug derived from Malaysian pit viper venom, is effective for ischemic stroke if given within three hours of symptom onset, but a new study shows it is not effective when given beyond three hours but within six hours, and increases the risk of short-term mortality and intracranial hemorrhage. The findings are published in the Nov. 25 issue of The Lancet.

Michael G. Hennerici, M.D., of the University of Heidelberg in Mannheim, Germany, and colleagues randomized 1,222 patients to receive ancrod or placebo within six hours after stroke onset. Functional ability at three months was similar in the active treatment and placebo group (42 percent in both groups), but neurological recovery was worse and there were more hemorrhages in the ancrod group than in the placebo group.

Mortality at three months was higher in the ancrod group than in the placebo group (20 percent versus 14 percent). At 12 months, however, there was no significant difference. "On the basis of our findings, ancrod should not be recommended for use in acute ischemic stroke beyond three hours," the authors note.

"Although the study was unsuccessful, it delivers an important message: that time from onset of symptoms to treatment matters, and in [this trial] it was too long," Markku Kaste, M.D., of the University of Helsinki in Finland, writes in an accompanying editorial.

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