Trick or treatment: Vampire bats transform Saint Mary's stroke-drug trial
Mother Nature put a silver lining on one of her more horrific creations, which is why Saint Mary’s Health Care in Grand Rapids is the coordination center for a nationwide clinical trial of a drug that may help stroke victims.
The chemical compound is desmoteplase, a synthetic version of a clot-dissolving protein found in the saliva of the vampire bat Desmodus rotundus, according to the website of Lundbeck, a Danish pharmaceutical company that commissioned the clinical trials. The drug has received fast-track designation from the U.S. Food and Drug Administration for study in the treatment of acute ischemic stroke, according to Lundbeck.
Desmodus rotundus, also known as the common vampire bat, according to the University of Michigan Museum of Zoology, has “large razor-sharp incisors and canine” teeth for making a small incision in its victim. “The bite is relatively painless and rarely wakes a sleeping victim,” according to U-M museum officials, and the bat’s specialized saliva prevents the blood from clotting so the bat can keep lapping it up to the point where the bat literally may have difficulty getting airborne again.
The common vampire bat is found from Mexico to Argentina and Chile. It will feed on sleeping humans, but most commonly feeds on domestic cattle. Vampire bat populations have increased because of the widespread introduction of livestock throughout South America. Its bite can transmit rabies, and it does millions of dollars worth of damage to the South American beef industry every year, according to U-M.
Saint Mary’s is the clinical coordinating center and one of about 60 sites in the U.S. studying the effectiveness of desmoteplase. In the study, it is used to treat patients presenting symptoms of stroke beyond three hours of onset.
Currently, tPA — the only FDA-approved drug for dissolving blood clots caused by stroke — must be administered within three hours of the onset of symptoms.
The challenge, according to information supplied by Saint Mary’s, is getting patients to the hospital in time to receive the treatment.
“Often, a patient experiencing acute ischemic stroke symptoms doesn’t recognize those symptoms or ignores them, which can cause irreversible damage, even death,” said Philip B. Gorelick, M.D., neurologist and medical director, Saint Mary’s Health Care Hauenstein Neuroscience Center and the co-director of the U.S. Desmoteplase in Acute Ischemic Stroke Trial.
The new drug may extend the window for life-saving treatment beyond the current three hours and up to nine hours.
“A small percentage of all stroke patients make it to the hospital within three hours of the onset of symptoms, so this new drug could potentially help many more patients avoid paralysis and, worse, death,” added Gorelick.
He noted that the desmoteplase clinical trials will involve about 200 patients in the U.S., plus another 200 patients in clinical trials in Europe. Some patients are also going to be from Asia. Gorelick said the trials in the U.S. may be completed by mid-2013.
Saint Mary’s emphasizes that 911 should be called immediately when someone experiences symptoms of ischemic stroke, meaning a stroke caused by blockage of an artery providing blood to the brain. The symptoms are:
- Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
- Sudden confusion, trouble speaking or understanding
- Sudden trouble seeing in one or both eyes
- Sudden trouble walking, dizziness, loss of balance or coordination
- Sudden, severe headache with no known cause
The Hauenstein Neuroscience Center, which opened in 2009, is a nationally certified stroke center.
Clinical research partnerships with the Van Andel Institute and the Michigan State University College of Human Medicine, along with the addition of Saint Mary’s Clinical Trial Unit, allows the expansion of research and medical treatment alternatives that may otherwise be unavailable. For more information, visit www.smneuroscience.org.
Gorelick mentioned in passing a “great irony” involving the other co-director of the program, a physician in Tennessee who selected the very first patient for the trial. While en route to the hospital in Chattanooga to visit the patient, the doctor was bitten by a bat, and subsequently had to undergo rabies shots.
But that’s just a coincidence.