Scientists have reported that a drug, which was withdrawn from clinical trials because of its poor safety record, has helped in the regrowth of brain tissue in Parkinson sufferers.
The drug GDNF- glial cell line-derived neurotrophic factor- was withdrawn by its manufacturer Amgen earlier this year after questions were raised over its safety. It was found to have caused brain damage in lab animals that had received high doses of the drug. This new finding will probably fuel fresh debate over its usefulness.
The drug had worked wonders in the trial before it was withdrawn. Patients had reported remarkable improvement when using it in the trials. After Amgen withdrew the drug, several participants of the trial had sued the company to provide them a supply of the drug. A New York judge had dismissed that case, but a second one is still pending.
In the meantime, researchers at the Frenchay Hospital in Bristol, England, have found that degenerated nerve fibres have regrown in a 62-year-old man who had received the drug in some early trials. This was found by them after conducting an autopsy on the man who died of a heart attack.
Seth Love, Steven S. Gill and colleagues have published these findings in Monday's issue of the journal Nature Medicine. Dr. Love said that the improvements that were shown by patients in the trials could be directly attributed to the fact that the degenerated nerve fibres were induced to regrow by GDNF. This is the first time that any drug has been shown to stimulate regrowth of brain tissue that has been damaged.
Parkinson's disease is a brain disorder that affects a part of the brain known as substantia nigra. The cells in this area of the brain produce a neuro transmitter called as Dopamine. This chemical is responsible for maintaining the coordination of the body musculature. When the disease affects 80 percent of the substantia nigra, there is a depletion of dopamine in the body and symptoms of Parkinson disease appear. These include tremor (shaking), slowness of movement, rigidity (stiffness) and loss of balance.
A patient with Parkinson's can be identified by the stiff facial expression that is characteristic of the condition. Almost 1.5 million Americans are affected by this condition, which occurs equally in both genders. Current treatment includes administering dopamine in various guises. It was believed that GDNF protects the dopamine-producing cells and hence the dramatic improvement in patients in the trial.
When asked to comment, Andrea Rothschild, an Amgen spokeswoman said that the company was continuing its study on GDNF, but that the trial would not be restarted unless all safety issues were addressed.
