Amgen to Stop Providing Trial Drug
As his condition worsened from Parkinson’s disease two years ago, Roger Thacker gave up working his sheep farm in Troy, Ky.
But everything changed when Thacker began taking an experimental drug from Amgen Inc. He became strong enough to hike through his fields and perform his old farm chores.
“It was a miracle,” said Thacker, now 65.
But Amgen said Friday it would no longer provide the drug, called GDNF, to the 48 patients who had been receiving it. The Thousand Oaks-based company said a clinical trial in June found that drug worked no better than a placebo. In September, the company found unexpected safety problems and stopped making the drug available as it assessed the data.
Amgen’s announcement prompted an outcry from patients and their families who viewed GDNF as their last hope.
Thacker’s condition has deteriorated so badly without the drug that he must use a wheelchair. Amgen’s decision was “totally wrong,” said his wife, Linda.
And Elaine Suthers of Huntinton, N.Y., whose husband, Robert, 70, had been on GDNF, said, “To me, it is like taking insulin from a diabetic.”
Amgen said it was deeply disappointed by the results of its study. “Our hearts truly go out to trial patients and their families,” Chief Executive Kevin Sharer said in a statement. “But we simply cannot allow trials to continue given the potential safety risks and the absence of benefit.”
GDNF was considered one of the most promising potential treatments for Parkinson’s disease, a degenerative disorder that affects an estimated 1.2 million people in the U.S., including boxing great Muhammad Ali and actor Michael J. Fox. There is no cure.
Although the cause is unknown, Parkinson’s symptoms stem from a lack of the brain chemical called dopamine. GDNF belongs to a class of naturally occurring growth factors that is believed to protect dopamine-producing cells.
Amgen had high hopes for the drug, although Wall Street expected it to be a modest moneymaker. At an analysts’ meeting last spring in New York, Amgen showed a video of a Parkinson’s patient who was able to jettison his walker after treatment.
Amgen’s shares rose 64 cents Friday to $63.42 on Nasdaq.
Patients in the trial received GDNF directly into their brains through tubes that led from pumps implanted in their abdomens. In the study of 34 patients announced in June, 17 patients received GDNF for six months while the rest received a saline solution.
At the end of the study, Amgen said it found no differences between the groups in performing such tasks as walking, talking and writing -- even if some patients believed that they did improve.
Some physicians said the trial did not appear to work partly because patients received too low a dose of GDNF. So Amgen tested higher doses of GDNF in 15 monkeys, but some of the animals suffered irreversible brain damage. After receiving those results in September, Amgen stopped providing GDNF to patients.
Scientists who administered GDNF to patients said there was another way to interpret Amgen’s data. Arif Dalvi of the University of Chicago said it was possible the monkeys might have been harmed not by large doses of GDNF, but by the sudden withdrawal of the drug.
“It is a little too early to conclude whether the drug works or not,” Dalvi said.
Last month, representatives of Amgen and a group of researchers met with the Food and Drug Administration to discuss the future of the drug.
“I was very optimistic,” said Don Gash of the University of Kentucky, who attended the meeting. “Amgen was very concerned about safety issues, but we all agreed these patients had gone through the riskiest part of the procedure, which is having the pump installed.”
Amgen took a month to review all the data. Donna Masterman, an Amgen neurologist who oversaw the trials, said the company concluded that the risks were too high.
“Patients with this disease are very desperate,” Masterman said. “But giving this molecule in this way is potentially harmful -- and it isn’t working.”
Amgen said it would continue to study the drug to see if there was a way to deliver it to the brain without risking damage.
William Langston, scientific director of the nonprofit Parkinson’s Institute, said he believed GDNF might one day be useful. But he said Amgen was right to withhold the drug from patients.
“This is not a very happy time for our field,” he said. “But you have to be dispassionate when you look at data.”
*
Times staff writer Joel Havemann contributed to this report.
