Experimental Drug From Snake Venom For Acute Stroke Patients
Yale-New Haven Hospital is participating in a phase III research study in which a drug derived from the venom of the Malayan pit viper is being tested for the treatment of stroke. This new investigative drug is known as ancrod, and is being tested in eligible patients who come to the hospital within six hours of the start of stroke symptoms.
Ancrod is an enzyme that is a potent, natural anticoagulant that helps restore blood flow. It accomplishes this by acting directly on fibrinogen, a protein involved with blot clotting. Ancrod adheres to fibrinogen to prevent clot formations, reduce blood viscosity and thus may improve blood flow to the affected areas of the brain.
"Currently, the only FDA-approved drug treatment for acute ischemic stroke is tPA," said Joseph Schindler, MD, clinical director of the Stroke Center at Yale-New Haven Hospital. "But tPa can only be given within three hours after stroke symptoms begin. If ancrod is safe and effective for treatment of ischemic stroke, it will double the time frame during which stroke patients can be treated following the onset of symptoms."
More than 750,000 people suffer from a stroke each year. Approximately 80 percent of strokes are ischemic, caused by a clot that blocks blood flow in the brain. Right now, doctors administer a "clotbusting" agent known as tissue plasminogen activator (tPA), but it must be given to eligible patient within three hours of the onset of the stroke symptoms. Only about 4 percent of patients actually receive tPA treatment, in part because many patients don't recognize the symptoms of stroke and delay getting to a hospital.
"Even though there is still a great deal of work to be done, we are confident that this research trial will clearly establish if ancrod is or is not safe and effective for treatment of acute ischemic stroke and overall improvement in stroke recovery," said Janet Halliday, RN, BS, research coordinator of the YNHH Stroke Center. YNHH is the only Connecticut hospital to be participating in the trial which is expected to last for a year or two, although the study results won't be known for several years.
"Part of our mission as a Primary Stroke Center is to raise the awareness of both providers and the public so that effective treatment can be delivered promptly," added Karin Nystrom, MSN, APRN, clinical coordinator of the stroke program at Yale-New Haven Hospital. "What people need to know, above all else, is that getting to the emergency room at once is the only way we can provide effective stroke treatment. As with a heart attack, time is of the essence. The more time goes by, the more damage occurs."