Drugs show small effects in Alzheimer's: research

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - Several new drugs showed early promise against Alzheimer's disease, but none had a dramatic effect, demonstrating that the battle against the brain-wasting illness will be long, researchers said on Monday.

One of the new drugs offers an alternative food source to damaged brain cells that can no longer make use of sugar, while another was originally developed as an antihistamine.

None of the drug studies presented at an Alzheimer's Association conference clearly affected the progression of the incurable illness, found in 26 million people globally and 5 million in the United States alone.

"I think this is just exactly what we should expect -- incremental progress," Dr. Sam Gandy, chairman of the association's medical and science council, told a news conference. He said Alzheimer's will likely be treated with a cocktail of compounds, similar to chemotherapy in cancer.

One drug, called AC-1202 or Ketasyn, provides an "alternative energy source" to brain cells that can no longer make use of glucose, said Dr. Lauren Costantini of privately held Accera Inc. in Broomfield, Colorado.

The drug causes the liver to act as if the patient is starving, producing compounds called ketone bodies.

"In neurons no longer able to metabolize glucose, they are able to metabolize ketone bodies," Costantini said.

They gave their drug, delivered in a morning milkshake, to 152 Alzheimer's patients who were taking one or more of the four licensed Alzheimer's drugs.

"Subjects taking AC-1202 for nine months showed little disease progression," Costantini said. Doctors measured memory problems and other aspects of day-to-day living.

Patients given placebo on top of standard drugs steadily worsened, she said.

The benefits stopped when the patients stopped taking the drug, Costantini said. The positive effects were only seen in patients who did not have a genetic mutation called APOE-4 that sharply raises the risks of Alzheimer's, she said.

MEASURING BLOOD

Eli Lilly and Co. used a different approach with its experimental new drug known by its code name LY450139. They did not directly measure memory but looked at levels of a protein in the blood called amyloid beta.

Amyloid beta is strongly linked with Alzheimer's disease. It helps build up the brain clogs or plaques that are a hallmark of the disease.

LY450139 interferes with a compound called gamma secretase that helps in the formation of amyloid.