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Researchers say they see promising results from the first gene therapy trial
for Alzheimer's disease. And one of the trial's patients, Lola Crosswhite,
believes the experimental treatment slowed down her disease for two years.
But now her memory loss is progressing again.
"Even though I've had it all this time, but then it was better," Crosswhite
says. "And now I feel like I know I'm sliding back so I¹m going down the
hill again."
In 2002, Crosswhite was one of eight patients to volunteer for the risky
brain surgery in hope of delaying her decline due to Alzheimer's.
The researchers, led by University of California, San Diego neuroscientist
Mark Tuszynski, took skin cells from the patients, grew them up in a culture
dish and genetically engineered them to make human nerve growth factor
(NGF). NGF has been shown in animal studies to protect brain cells from
deteriorating.
The cells were then injected into the area of the brain where cells were
dying due to Alzheimer's. In this way, the implanted cells act as biological
pumps for the local delivery of the growth factors in the brain. "The growth
factor released by these genetically engineered cells will bath the other
cells in the growth factor, slow down the degeneration and thereby improve,
or slow the decline in Alzheimer's disease," Tuszynski explains.
The team reported in the journal Nature Medicine that during the two years
the gene worked, it successfully slowed the progression of the disease by 49
percent on average.
"Measured on the same scale, the existing drugs have a five percent effect
that last three to six months," says Tuszynski. "So that 49 percent compared
to five percent would be great if it holds up and that's a big if."
He says the next trial will use an improved delivery method, or vector, that
should keep the gene working longer.
"So we won't cure the disease, but again what we hope to do is delay the
disease for a significant and meaningful period of time," Tuszynski says.
"The chance of doing that will be greater with the next generation vector
that we are now testing in the next human clinical trial.
Crosswhite's daughter Diana Shaw says she's grateful for the extra time.
"But she's a fighter, she doesn't, she's not going to give an inch or
anything," So we're going to go out fighting.
The safety trial of the new gene delivery method is now underway at Rush
University Medical Center in Chicago.
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