X-Message-Number: 12173 Date: Thu, 22 Jul 1999 16:34:18 -0400 From: Jan Coetzee <> Subject: Limit Stroke Damage New Compound May Help Limit Stroke Damage - Study By Maggie Fox, Health and Science Correspondent WASHINGTON (Reuters) - An experimental new drug might help limit the damage caused by stroke by preventing the immune system from spilling over and damaging delicate nerve cells, researchers said Thursday. The drug has only been tested in mice. But the testing supports the idea that inflammation after a stroke brings about a cascade of cell death in which brain cells are destroyed over several hours or even days. The compound, known by the experimental name of TP20, is made by Needham, Massachusetts-based Avant Immunotherapeutics Inc. (Nasdaq:AVAN - news). Dr. David Pinsky, a professor of medicine at Columbia University in New York who helped test the drug, said it works in two ways -- first by stopping one part of the immune system, known as complement, from activating. Complement is a series of proteins that punch holes in cells, destroying them. It is meant to act against invaders but ''it is a little bit indiscriminate once it is activated,'' Pinsky said. But second, the compound was modified by Avant, Pinsky added. ``It was coated with a very special sugar which interferes with adhesion receptors -- those are basically sticky molecules on the surface of cells. It prevents white blood cells and perhaps platelets from coming into the area and gumming up the blood vessels.'' Each year about 550,000 Americans suffer a stroke. There are two kinds -- ischemic and hemorrhagic. In an ischemic stroke a blood clot cuts off blood to the brain. Some brain cells die instantly. But other brain damage develops slowly, sometimes over weeks, as cells die. Drugs that can stop this could help prevent the paralysis, speech problems and other brain dysfunction that can cripple stroke victims. The brain is protected from the immune system by a system known as the blood-brain barrier. When a stroke occurs, Pinsky said, the immune cells -- and complement -- can spill over and damage delicate neurons. But Pinsky's team found something else. ``One of the new findings was the fact that nerve cells, when they are subjected to ischemia, when they are in an area where blood flow is diminished, they express this complement protein on their surface,'' Pinsky said. ``They bristle with it. It's all over them. That's what triggers this system.'' Pinsky said it is too soon to tell how quickly TP20 would have to be given after a stroke to do any good. He said it is a long way from being tested in human beings. This ``window of opportunity'' is important. The only drug on the market to limit damage after a stroke is Genentech's clotbuster Activase, which is also known as tissue plasminogen activator or tPA, and it must be given within three hours to work. Many other companies are working on drugs, however. Abbott Laboratories (NYSE:ABT - news) Inc. says its clot-busting drug, recombinant pro-urokinase, can be used six hours after a stroke. It is expected to seek approval this year. Interneuron Pharmaceuticals Inc. (Nasdaq:IPIC - news) says CerAxon, known generically as citicoline, is in Phase III clinical trials in people, the last stage before seeking approval. Parke-Davis, a division of Warner-Lambert Co., is testing an experimental drug known as PD098058. Ancrod, made by Knoll Pharmaceuticals, lowers the level of fibrinogen in the blood, which is necessary for clotting. Creative BioMolecules Inc. says its drug OP-1 appears to help the brain compensate for areas damaged by stroke, and works up to 72 hours after a stroke. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=12173