Lauran Neergaard, Washington: Drinking a milkshake-style medicine at breakfast seems to feed brain cells starved from Alzheimer's damage, researchers reported Monday. It is one of four promising experimental drugs poised for large-scale testing against the brain-destroying disease.

The milkshake drug, called Ketasyn, provides a dramatically different approach to dementia. It hinges on recent research that suggested diabetic-like changes in brain cells' ability to use sugar for energy play a role in at least some forms of Alzheimer's.

Special fatty acids in Ketasyn offer an alternate food source to rev up those hungry neurons, researchers told an international Alzheimer's meeting in Washington on Monday. In a study of 150 patients, adding Ketasyn to their regular medicines produced a small but important boost in mental functioning but only in people who do not carry an Alzheimer's gene called ApoE4. Still, that is about half of all patients.

''We see this as a co-therapy,'' not a way to stop Alzheimer's, cautioned Dr. Lauren Constantini, a former Harvard University scientist now with the company Accera Inc., which is developing the drug.

Indeed, to stop Alzheimer's brain decay, most scientists have their hopes pinned on drugs that promise to prevent a sticky goo called beta-amyloid from clogging patients' brains. Monday brought frustrating news on that front: The first of those amyloid blockers to make it to large-scale, Phase III testing has hit a hurdle, and scientists will have to wait until at least month's end to learn if the much-anticipated drug Alzhemed works.

The problem is statistical, said lead researcher Dr. Paul Aisen of Georgetown University: Hospital-to-hospital differences in other medication use among the study's 1,000 participants prevent an immediate clear comparison of Alzhemed's role. Working with the Food and Drug Administration, researchers are adjusting for those variations, Aisen told the Alzheimer's Association's dementia prevention meeting.

Stay tuned, he said. There are hints that Alzhemed-treated patients fared better.