Eli Lilly announced that it prepares a phase III trial for its experimental drug for Alzheimer's, LY450139. The IDENTITY Trial - Interrupting Alzheimer's Dementia by EvaluatiNg Treatment of AmyloId PaThologY, is a randomized, double-blind, placebo-controlled trial that will be conducted in the U.S. and 21 additional countries on some 1,500 patients for 21 months.

"We encourage patients or their caregivers to review the enrollment criteria for IDENTITY to see if they are eligible to participate," said Eric Siemers M.D., Medical Director, Alzheimer's disease research for Eli Lilly and Company, in a statement.

The LY450139 drug inhibits gamma secretase, an enzyme that cuts a protein, creating a shorter, sticky protein called amyloid beta, which may lead to reduction in plaques which are known to eventually kill off brain cells in Alzheimer's disease. Side effects observed earlier with LY450139 include diarrhea, upset stomach, and fatigue, the company said.

So far, there is no known cure for Alzheimer’s. The U.S. will be faced with a half-million new cases of Alzheimer’s a year in 2010 and nearly a million a year by the middle of the century if no cure for the disease is discovered, a recent report released by the Alzheimer’s Association has estimated.

The report also draws attention on the negative impact the growing numbers will have on U.S. economy. In 2005, Medicare spent $91 billion on Alzheimer's and other dementias, and spending could jump to $160 billion by 2010 and $189 billion by 2015. Also, the time and out-of-pocket costs for family caregivers will increase, the report wrote.

Nearly 5.2 million people now have Alzheimer’s and as many as 500,000 Americans are diagnosed before the age of 65. It is estimated that even a treatment that delayed the age of onset for Alzheimer’s could save Medicare billions.