New drug candidate for stroke makes progress
of failed projects, so any data suggesting that a drug has activity
in this indication should be greeted with cautious optimism at
best. But AstraZeneca has joined those vying to become only the
second approved drug for stroke.
The company has just undertaken a preliminary examination of data from an ongoing trial of Cerovive (NXY-059), an antioxidant compound it licenses from US biotechnology company Renovis, and concluded that the results support continuation of the study.
During a stroke there is production of highly reactive oxygen free radicals that can destroy cellular membranes in a cascade effect, radiating out from the site of injury. Consequently, free radical scavengers, such as Cerovive, might have a potentially neuroprotective role, preventing this spread of tissue damage.
Numerous studies in animal models have been suggestive of this action and have shown that the drug can reduce infarct size and improve neurological outcome following a stroke.
During the 1990s, a number of potential neuroprotectant drugs that block glutamate excitotoxicity were tested. In animal models of acute ischemic stroke, many of these drugs were effective in mitigating further damage caused by the stroke cascade when given within 30 minutes, and occasionally up to two hours, after stroke. However, when subsequently tested in human patients up to 12 hours after stroke, they did not demonstrate statistically significant efficacy.
Stroke is the third leading cause of death in North America and Western Europe and the most common cause of adult long-term disability in the US, but there is only one stroke therapy approved for marketing. This is Genentech's tissue plasminogen activator Activase (alteplase or rt-PA), a thrombolytic that targets the offending blood clot within the brain and marked a revolution in stroke management. However the very short window of opportunity for administering rt-PA to stroke victims limits the usefulness of this treatment.
Datamonitor notes that the potential market for an efficacious and safe stroke drug is enormous, given the high incidence of the disorder worldwide. Assuming a relatively conservative cost of treatment of $1,000, for example, the market is potentially worth half a billion dollars annually in the US alone.
