Cambridge NeuroScience Inc. (CNS) announced Wednesday thatit has received the go-ahead from FDA for U.S. clinical trials onCerestat for preventing brain damage in patients with stroke.
Cerestat is an NMDA (N-Methyl-D-Aspartate) ion-channelblocker. In particular, it blocks the flow of calcium into braincells. The interrupted flow of blood to the brain followingstroke causes nerve cell death. The damaged nerve terminirelease excessive glutamate (a neurotransmitter), which in turnstimulates the entry of calcium into those nerve cells, leadingto further nerve cell death and brain damage. Cerestat blocksthat calcium flow by occupying its channel. "It cannot bedisplaced by glutamate," said Elkan Gamzu, president and chiefoperating officer of the Cambridge, Mass. company(NASDAQ:CNSI).
There has been some controversy surrounding the use of suchneuroprotective drugs in humans because they have beenshown to cause the formation of vacuoles in the brains ofanimals. This phenomenon, however, is reversible. "It'sbelieved to be the case that all compounds that act at that sitedo this, and that it represents a hyperactivity by the narrowband of cells found in the area of the brain termed theretrosplenium," Gamzu explained.
However, he pointed out that CNS's compound, given to ratsintravenously at a "dose that would produce a neuroprotectiveeffect, and at 10 times that dose" did not produce anyvacuolization.
CNS plans to enroll patients in its Phase Ib trials in the U.S. inFebruary. Phase Ia studies of Cerestat have been under way inthe United Kingdom since last August. Gamzu noted that thesestudies, with doses administered over longer time periods, arenearing completion. In addition, the company expects to beginanother Phase Ib study of Cerestat in the United Kingdom thisquarter in patients with traumatic brain injury.
-- Jennifer Van Brunt Senior Editor
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