Nightly News | April 07, 2013
>>> the urgent need for better treatment of alzheimer 's disease and other kinds of dementia was highlighted this past week with a report that said dementia cost this country as much as $215 billion a year. well, now there is a fascinating study going on involving some new drugs that might prevent alzheimer 's. we get details tonight from nbc's chief science correspondent robert bazell .
>> reporter: this family from davenport, iowa are among 100 families worldwide taking part in a daring experiment.
>> it is an exciting time. it is very exciting, it is also very scary.
>> reporter: each member of these families has a 50%-50% chance of getting a rare genetic mutation that causes alzheimer in the mid 40s, 50s and sixes it. an enormous mile post -- scientists have chosen three drugs that could stop some of them from having a certain future of alzheimer 's disease.
>> there is hope that we've got something to move forward on.
>> reporter: in the drug trials which started last month, family members are receiving either active drugs or placebo. based on brian scans and other biomarkers, researchers will decide which drugs look best and continue with those to see if they can prevent alzheimer 's or at least slow the progression. the three drugs target a protein that many scientists believe causes alzheimer 's. not just in families with a rare mutation, but also in the common form that strikes later in life. similar drugs have failed to halt alzheimer 's. scientists now believe they gave them too late. from studying families, they've learned the brain decay of alzheimer 's begins decades before symptoms. this study is not waiting for symptoms.
>> in a family that has an early onset, say at 35 years, they can be as young as 20 and still enroll in this.
>> you could be giving drugs to people as young as 20.
>> all three of these individuals carry a gene mutation .
>> reporter: sign ticientists see this as their best shot yet.
>> we have a good chance to prevent brain cells from dying and hopefully preventing the onset of alzheimer 's dementia.
>> reporter: the scientists hope to see results within two or three years. robert bazell , nbc news, st. louis.