LOS ANGELES, CA (Catholic Online) - Most of the test subjects have no symptoms of the degenerative disease. Researchers hope that the drugs may be head off the onset of Alzheimer's.

Another study starting next year involves an extended family in Colombia that shares the mutation that causes the disease. A third study will involve people in the U.S., aged 70 and older who seem perfectly healthy and who do not have any known Alzheimer's mutations but who have brain scans that show the disease is manifesting itself. 

Studies involving people who already have Alzheimer's have failed. Scientists have begun to call for studies in those who do not yet have the disease, saying that the time to intervene is before the brain is irreversibly damaged. The initial study, where people who are destined to get Alzheimer's unless a drug can stop it is a way to test that idea.

"It's an exciting opportunity," Dr. Ronald Petersen, director of the Alzheimer's disease Research Center at the Mayo Clinic says. Petersen is not involved with the study.

Vice President of Medical and Scientific relations at the Alzheimer's Association Maria C. Carrillo says that the results will come quickly. As researchers simultaneously compare the three approaches to stopping the disease over the five years, they should know which drug -- if any -- is going to work. The association contributed $4.2 million to the study, more than twice as much as it has ever spent on a grant, Carrillo says.

Investigators have found ways of spotting and tracking the progression of the disease before any clinical symptoms appear over the past several years, using brain scans and spinal taps and sensitive tests of memory. Many think they are on the brink of a new era in which drugs can be assessed without waiting for effects on profound symptoms.

Deemed DIAN TU, which stands for Dominantly Inherited Alzheimer's Network Trials Unit, the study is designed to get the most information possible in as short a time as possible. Three-quarters of the subjects will get one of three drugs aimed at beta amyloid, a protein that forms the hard plaques on the brain that are the hallmark of Alzheimer's.

The three drugs were chosen from among 15 that drug companies offered. A committee assessed them, looking for drugs with the best evidence of effectiveness and the least likelihood of dangerous side effects.

Researchers will follow the subjects with scans and memory tests in the first two years of the study, looking for signs that the drugs are working. If one or more seems clearly effective, they will switch all the subjects to it and continue the study, looking for clinical benefits.

The drugs to be tested are gantenerumab, made by Roche, which binds to clumps of amyloid and allows it to be removed from the brain, and two drugs by Lilly. One, known as LY2886721, blocks an enzyme, beta-secretase, used to make amyloid. The other, solanezumab, attaches itself to amyloid that is floating free in the brain before it clumps into plaques, facilitating its removal.

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