This is Phoebe Zimmermann with the VOA Special English Health Report.

Researchers say two experimental drugs may be able to slow or even stop the progress of Alzheimer's disease. This condition kills brain cells. People over the age of sixty-five have an increased risk of developing it. So do people with a family history of the disease.

Scientists announced new findings during an international conference last month in Philadelphia, Pennsylvania. The Alzheimer's Association organized the meeting.

The new experimental drugs are designed to interfere with a protein called beta-amyloid. This protein sticks together. It forms areas of plaque found in the brains of people with Alzheimer's disease. Many scientists believe it kills brain cells.

Scientists at Georgetown University Medical Center in Washington, D.C., tested a drug called Alzhemed. The study involved two groups of people with mild to moderate Alzheimer's disease. One group took Alzhemed. The other took an inactive substance. Neither group knew which one they got.

The scientists say the group treated with the drug had a sharp drop in the level of beta-amyloid in spinal fluid from the brain. No changes were reported in the other group.

Doctor Paul Aisen led the study. He said people who started with mild Alzheimer's suffered no further memory loss after a year on the drug. He said there were no serious side effects. This drug is now in final testing.

The other experimental drug is a compound known as l-y-four-five-oh-one-three-nine. This is designed to block the formation of enzymes that produce beta-amyloid. Researchers from Eli Lilly and Company in Indianapolis, Indiana, led this study. It involved thirty-seven healthy adults over forty-five years old.

The researchers say levels of beta-amyloid in the blood fell after the group took the experimental drug for two weeks. They say greater amounts of the drug led to greater reductions.

Experts say more than fifteen million people around the world have Alzheimer's disease. These include four million Americans. Scientists are not sure what causes it. But they believe that genetic and environmental influences are both involved.

Alzheimer's disease begins with mild memory loss. It gets worse and worse, until it robs people of their mind. Current drugs mostly treat only the signs of the condition. But they do not stop the disease or cure it.

This VOA Special English Health Report was written by Cynthia Kirk. This is Phoebe Zimmermann.