By Robert Davis
USA Today
Copyright 2008 Gannett Company, Inc.
KATY, Texas — The whole episode remains a blur to Kenneth Transeau of Katy, Texas, as he was flown by an air ambulance to a stroke center in Houston. But sometime after the noisy ride and the hurried brain scans, Transeau went from being a stroke patient to a test subject.
Researchers are trying to find out if they can help patients like Transeau, 69, by dripping an experimental drug made from viper venom into their veins.
The pet supply salesman, 69, doesn’t recall anybody mentioning risks. “They may have,” he says. “I just knew I wanted to take it. I knew they wouldn’t be testing it if it wasn’t safe.”
But the safety of the drug Viprinex is anything but certain.
Similar human studies were “an abysmal failure in Europe,” says Paul Freiman, president and CEO of Neurobiological Technologies, a U.S. company testing the drug.
For the record, Transeau was told of the risks, the hospital says.
His wife, Irene, signed the consent form, which detailed the bleeding and deaths recorded in previous studies, to enroll her husband in the worldwide trial that hopes to study 650 patients. “We’re taking this (failed experiment) and transforming it” by changing the way it is administered, Freiman says.
The study, launched in November 2005, is designed to determine whether infusing select parts of Malaysian viper venom into some patients can halt a stroke and prevent more brain damage. For years, the concept has tempted scientists, who believe the way the snake’s venom kills also should help doctors put the brakes on a stroke.
Why it might work
When a blood clot forms in the brain, doctors try to dissolve it while getting blood to flow more freely around the blockage and in smaller blood vessels nearby so surrounding neurons can survive.
The viper’s venom causes its prey’s blood to thin, a transformation that is exactly what doctors want to happen when trying to reverse a stroke caused by a clot, only on a much smaller scale.
“The snakes cause their victims to bleed to death internally,” Freiman says. “It would be nice if you could thin blood out like this for stroke victims.”
Transeau’s case shows the typical race against time doctors face when they encounter a stroke patient. A stroke occurs when blood flow is cut off to part of the brain, either because of a blood clot or because of bleeding in the brain, causing the brain tissue to die. More than 700,000 strokes occur in the USA each year, making it the leading cause of disability and the third-leading cause of death.
“In an average stroke, 2 million neurons die per minute in the first few hours, so we are racing against the clock,” says Transeau’s doctor, David Chiu, director of the Eddy Scurlock Stroke Center at Methodist Neurological Institute in Houston. “The earlier we treat, the better the benefit.”
The best drug Chiu has is the clot-busting drug known as tPA, tissue plasminogen activator, which must be given within three hours. The study of Viprinex is trying to determine whether the snake venom can give doctors twice as much time — six hours — to treat a stroke.
 The snakes cause their victims to bleed to death internally. It would be nice if you could thin blood out like this for stroke victims.  | ||
| — Paul Freiman President/CEO, Neurobiological Technologies | ||
Extra time is key because people often respond too slowly to signs of a stroke, experts say.
Viprinex is a new class of drug, says Warren Wasiewski, vice president and chief medical officer for Neurobiological Technologies. It makes blood flow more freely, and it may break up clots.
By reviewing what worked and what didn’t work in 2,000 patients previously given the drug, researchers suspect that too much of the drug was given. The current trial reduces the amount.
Chui, who is an investigator in the study but who has no other financial ties to the company, says Viprinex “could be a major advance in the treatment of stroke” if it works. He says the trial is a reminder that even failed clinical studies can lead to advances.
“We have learned some valuable lessons from the failed trials,” he says. “We have to be smarter at selecting patients who stand to benefit from treatment.”
At least one success story
Transeau is convinced the speedy recovery that has allowed him to return to work is a result of the drug. He speaks well and has regained his strength and motor skills through physical therapy.
“I think if I had the placebo and not the actual pit viper venom, I don’t think I would be as far along as I am today,” Transeau says. “I started speaking the next day, and my writing became more legible as each day went along.”
But neither he nor Chui knows whether he got the drug because it is being used in a double-blind study against a placebo. No one knows who is receiving what, but all of the trial participants get standard care for stroke victims.
The method is considered the gold standard in clinical trials because it is thought to produce objective results.
The study might show Transeau benefited only from the speedy help. He and his family recognized the stroke from his impaired speech during a cellphone conversation. Paramedics found him on the side of the road in about 15 minutes, he says, and they called for a helicopter to take him directly to the specialty hospital.
Chui says the most immediate way to help stroke patients is for family members and friends to be more aware of signs and symptoms and for them to act quickly to get patients to specialty hospitals.
“We need to do better in the community,” he says. “It’s not something you can afford to delay treatment for.”