Dec. 28, 2004 -- For Kentucky schoolteacher Barbara Allen, the symptoms began with stiffness in her arm. She thought it was arthritis.
But within a year, a neurologist broke the devastating news: she was suffering from Parkinson's disease, a degenerative condition that causes sufferers to shake with tremors, slip into moments of paralysis and endure increasing pain.
"I'm very independent, some say headstrong, some say stubborn," said Allen, "and my biggest fear is that I will be lying there frozen, cannot move, and my mind's still working actively."
But Barbara's doctors offered her unexpected hope -- an experimental drug called GDNF.
A pump implanted in her abdomen kept a constant flow of the drug into her brain. The results she saw were stunning.
"I was moving and could do the things I could do before -- people back in town and acquaintances and colleagues all could see that Barb is doing better, Barb's back -- it was me again," she said.
Other patients, like Steve Kaufman, noticed similar changes.
"Every day was difficult. I'd come home from work totally exhausted," said Kaufman. "You would think being so exhausted I could sleep -- sleep was a luxury. I could not sleep at all. [If] I'd get an hour I'd be very lucky."
But after taking GDNF, Kaufman was able to rebuild the deck outside his Chicago-area home. It's a feat his wife Maggie thought would never be possible.
"He would get up and start doing things around the house," Maggie said, "which was incredible because [before] when he would come home, he would be sitting on the couch shaking and in pain all the time and wouldn't be able to do anything, so it was pretty miraculous."
Drug Maker Suddenly Ends Experiment
But in August, patients on GDNF heard stunning news. Amgen, the drug company that manufactures GDNF, announced the experiment Allen and Kaufman took part in was "inconclusive." Amgen also presented data showing that monkeys exposed to GDNF had suffered brain damage.
By September, Amgen ordered the drug drained from patients' bodies.
In a statement to "Good Morning America," Amgen said "the decision to stop providing GDNF was based solely on our concern for patient safety" and "our hearts go out to the trial patients who had such hope for this experimental drug."
Patients In Limbo
Bioethicist Mark Siegler says Parkinson's can be especially difficult to study because the "placebo effect" may make patients feel they're getting better -- even if they're not.
"As experiments go, this is about as bold as an experiment can be, but some experiments work, and some experiments don't work," said Siegler.
The situation leaves patients in a desperate limbo -- holding out hope for a drug they thought would change their lives.
"I understand the risk involved," said Allen. "I had this surgery and I took this drug of my own volition. It wasn't something I had to do, and I was thankful to get it."
To learn more about patients' efforts to get access to GDNF, visit www.gdnf4parkinsons.org.