June 18, 2004

Two studies seek to lessen effects of Alzheimer’s disease

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Vice Chancellor Harry Jacobson, M.D., presented a lecture titled “Reforming Medical Education and Health Care” to VUSN students and faculty Tuesday afternoon. Photo by Dana Johnson

Two studies seek to lessen effects of Alzheimer’s disease

Alzheimer’s disease received national attention recently when one of the most famous people to suffer from the disease, former President Ronald Reagan, died on June 5 at the age of 93.

Reagan told the world he had Alzheimer’s disease a decade ago. In a letter, Reagan wrote, “I now begin the journey that will lead me into the sunset of my life.” He said he and his wife, Nancy, felt it was important to share the information with the public to raise awareness. “In opening our hearts, we hope this might promote greater awareness of this condition. Perhaps it will encourage a clearer understanding of the individuals and families who are affected by it,” he wrote.

Vanderbilt University Medical Center is one of 60 sites in the United States and 15 in Canada testing a new drug that has been shown to enhance the re-growth of neurons in in vitro testing, and has enhanced memory in aged rats and primates in animal testing, which may help those suffering from Alzheimer’s disease.

The study of the drug xaliproden is sponsored by Sanofi-Synthelabo Inc., the European pharmaceutical company that manufactures the drug. The study of 1,200 patients in North America, 2,400 worldwide, with mild to moderate Alzheimer’s disease is designated as a Phase III study by the Food and Drug Administration, meaning the drug is being tested for efficacy. The study will last 21 months, and about 30 individuals are expected to be enrolled at Vanderbilt.

Harry E. Gwirtsman, associate professor of Psychiatry and director of the division of Geropsychiatry, is the principal investigator of the Vanderbilt portion of the study. He said the in vitro test results are especially hopeful for Alzheimer’s patients since those patients experience the death of neurons. “If you can somehow stimulate neurons to re-grow the tentacles, perhaps we can preserve memory or the ability to learn new information,” he said.

The animal tests are also encouraging, he said. It is believed the drug mimics or enhances the effects of naturally-occurring neurotrophins such as nerve growth factor, brain-derived neurotrophic factor and neurotrophin.

Xaliproden has already been tested for toxicity in 2,000 patients with amyotrophic lateral sclerosis (ALS) and 199 patients with Alzheimer’s disease.

The study will be a double-blinded, placebo-controlled study, meaning that half of the study subjects will receive xaliproden and half a placebo. Neither the patient nor the investigator will know the patient’s group. Gwirtsman said that most Alzheimer’s patients are on other memory-enhancing drugs, and that they will be allowed to remain on those drugs while enrolled in the study. “Patients who participate in this trial will have nothing to lose in terms of their treatment,” he said, adding that other Alzheimer’s studies are currently being planned at Vanderbilt.

Alzheimer’s disease has no cure and causes the brain to slowly lose its ability to function. This results in a gradual loss of memory and other mental abilities, such as thinking, reasoning and knowing how to behave. Alzheimer’s disease is the most common cause of dementia in older people, with the risk going up after the age of 65. About 4 million to 5 million Americans have the disease.

The disease is classified into three stages — mild, where the person starts to lose short-term memory; moderate, where he or she needs more help with activities of daily living; and severe or final, where the person can no longer make decisions, has a hard time speaking, and may not recognize loved ones.

Alzheimer’s disease is uniformly fatal in six to 20 years after diagnosis, Gwirtsman said. Once patients progress from mild to moderate, they usually live for another four to six years.

“The quality of life deteriorates with time, even when patients are on commercially-available medications. There’s just a slower rate of decay for those on some type of medication,” Gwirtsman said. The disease is also a very difficult one for the patient’s caregiver. They normally spend more than 60 to 70 hours a week taking care of their loved one who has the disease. About 25 to 50 percent of those moderately ill, and 50 to 75 percent of those who are in the severe stage end up in a nursing home.

Gwirtsman is also the principal investigator of another study being conducted only at Vanderbilt, studying those at risk for Alzheimer’s disease. The study, now in the recruitment stage, will test 15 subjects, ages 40 to 85, at risk for Alzheimer’s disease. To be considered in the at-risk portion of the study, the volunteers must have a first-degree relative with the disease (father, mother, sister, brother, child) and a gene that puts them at risk. The gene for the protein Apo E, found on chromosome 19, is a risk factor that may be involved in Alzheimer’s disease. If patients have either of those risk factors, their risk of developing the disease is magnified two to four times, Gwirtsman said.

This group will be studied against a group of 15 subjects who have been determined to have no risk factors. The study involves using memory tests and special MRI scans to test for cognitive ability. Both groups will undergo genetic testing prior to being enrolled, however genetic results will not be given to the participants.

“If we see a difference in the scans of each group, there is the possibility we could detect this illness earlier than normally detected,” Gwirtsman said. “By the time it’s detected now, their brains are too far gone to be significantly improved by treatment.”

For more information about either of the studies, call 322-4865.