MEMORY DRUG TO BE TESTED ON ALZHEIMER'S PATIENTS.

Byline: Paul Recer Associated Press 

A new drug, which in some tests of healthy elderly men restores memory almost to that of young people, soon will be tested on patients with Alzheimer's, the fatal disorder that destroys the mind.

Dr. Gary Lynch of the University of California, Irvine, said Sunday the drug called ampakine CX-516 accelerates signals between brain cells and appears to sharpen the memory significantly.

The drug, used in only mild doses, was tested on students in their early 20s and on men 65 to 70. The results were ``particularly striking'' among the older people, Lynch said. He delivered a report on the drug Sunday at a national meeting of the Society for Neuroscience.

Lynch said clinical trials of the drug consisted of memory tests conducted with and without CX-516.

Before taking the drugs, the subjects were read a series of nonsense syllables, then asked five minutes later to recall as many of them as possible.

On average, the elderly could recall only one of the syllables. The young men averaged four out of 10.

The subjects later were given mild doses of ampakine CX-516, then retested.

``The result for the 65- to 70-year-old men was particularly striking,'' said Lynch. ``They scored near the range of young people.''

In some tests even the young experienced improvement in memory by about 20 percent, he said.

Lynch said the drug's developers hope it will improve the memory of patients with Alzheimer's disease, a progressive disorder that destroys memory and other functions of the brain and eventually kills. About 5 million Americans - most of them elderly - have Alzheimer's. The number is expected to climb to 15 million in the next 25 years as the proportion of elderly people in the nation increases.

Ampakine CX-516 has been tested only on small groups in clinical experiments to detect any toxic effects. A more definitive test will start next year at the National Institutes of Health, where the drug will be given to 16 patients with mild to moderate symptoms of Alzheimer's disease.

Dr. Donald Price, a neuroscience researcher at Johns Hopkins University in Baltimore, said the new drug is ``intriguing and innovative'' and can influence ``a very important synapse'' in the brain.

He said, however: ``I have reservations about its use in Alzheimer's because it does not directly address the disease mechanism. It is a palliative.

``I would suspend my enthusiasm until I see the results of the clinical trials.''

Lynch and colleagues at the University of California, Irvine, discovered the drug in 1991 while searching for compounds to improve communications between neurons in the brain. He said it works by causing neuron switches, called synapses, to remain open for a fraction of a second longer. This enhances the flow of an amino acid called glutamate. The exchange in effect carries a message from one neuron to another.

In 1993, ampakine CX-516 was tested on laboratory animals. Researchers found that older rats given the drug had a dramatically improved ability to find their way out of a maze and to remember the route later.

``It reduced the (needed) training sessions for older rats from 10 to five,'' said Lynch.

Human trials of the drug started last year. Results will be published in January in the journal Experimental Neurology.