Doctors look to virus for cure: Trials begun for Parkinson’s patients
Published: December 15, 2005
Mike Castle lay motionless as surgeons drilled two holes into his skull and injected a virus deep into his brain. The virus carries a gene and a tantalizing hope: Maybe it could stall the Parkinson’s disease slowly crippling him.
The Illinois man is among a few dozen patients enrolling in the first attempts at gene therapy for Parkinson’s, a milestone in the quest to better treat the degenerative brain disease.
It’s a time of mixed excitement and caution: These first three studies are to see whether gene therapy is safe to try, not to prove whether it works. Yet studies in monkeys suggest at least one of the approaches has the potential to finally target the underlying disease, not merely tame its symptoms.
“It’s this delicate balance between giving” patients “hope but making it clear to them, and to the world, that this is still highly experimental,” said William Marks Jr. of the University of California-San Francisco, who is leading the most closely watched approach - using a nerve growth factor to rescue dying brain cells.
Parkinson’s disease gradually destroys brain cells that produce dopamine, a chemical crucial for the cellular communication that controls muscle movement. As dopamine levels drop, symptoms increase: tremors in the arms, legs and face; periodically stiff or frozen limbs; slow movement; impaired balance and coordination. It afflicts about 1.5 million Americans.
Standard treatments are to replace lost dopamine with the drug levodopa and a brain implant to control tremors. Both work for a while but can’t stop the disease’s inevitable march. To do that, scientists have long sought ways to protect remaining dopamine-producing neurons and rescue dying ones. A candidate: growth factors, protective proteins naturally found in healthy brains.
In the UCSF and Rush study, the brains of 12 patients are being injected with a harmless virus that carries the gene for one growth factor, called neurturin.
Neurturin is a sister to the better-known growth factor GDNF, an experimental drug believed to be showing promise against Parkinson’s until a study infusing it directly into the brain was halted for safety concerns. Moreover, infusions don’t allow the growth factor to spread deep enough to reach Parkinson’s most crucial brain region, Verhagen says.
Scientists hope gene therapy can get around those issues. Rush neuroscientist Jeffrey Kordower found that monkeys with Parkinson’s-like damage significantly improved within three months of receiving growth-factor gene therapy, as injured neurons were rescued. He co-founded California-based Ceregene Inc., which is developing the neurturin gene therapy.
If you enjoyed this good news Subscribe to Good News Blog
Share this
To share this simply copy and paste one of the below URL's: