Study: Preliminary Results Suggest Compound is Safe
　　
Preliminary results from the first human study of a possible Alzheimer’s vaccine suggest the experimental compound is safe, San Francisco’s Elan Pharmaceuticals announced at the first World Alzheimer’s Congress today. 

The experimental vaccine, known as AN-1792, garnered attention last year when the company, a subsidiary of Ireland’s Elan Corporation, discovered that the compound could ward off and even reduce Alzheimer’s signature brain-clogging amyloid plaques in mice.
　　"In the brains of Alzheimer’s victims we find a protein that’s widely assumed to play a major role in the cause of this disease,"?ABCNEWS ’medical correspondent Dr. Timothy Johnson explained on today’s Good Morning America.
　　“So scientists have been able to produce a strain of mice in which they can simulate Alzheimer’s…then take some of this protein and inject it into the mice like a vaccine, stimulating the immune system."?/p>

Mice Are Not Human
　　“Of course, mice aren’t humans,"?cautioned Elan’s lead scientist Dale Schenk.
　　The company has begun small studies in people to see if the vaccine is safe. In the first safety results from those Phase 1 trials, none of the 24 Americans with early Alzheimer’s who received a vaccine injection suffered side effects, Schenk said. “There’s no question the vaccine was well-tolerated,"?he told the international meeting of 2,800 Alzheimer’s researchers.

Holding Our Breath
　　“Everybody is now holding their breath about the next stage which would be to test it for effectiveness in humans,"?Johnson said.
　　 The company hopes to launch those effectiveness studies by the end of 2001. Elan is enrolling 80 British patients with early Alzheimer’s into another Phase 1 study and giving them three shots of the vaccine over several months. Their immune systems will be checked for early signs that the vaccine is strong enough to activate immune cells necessary to fight disease.
　　Although no one knows if the vaccine ultimately will help, the experiments are hopeful because they are grounded in years of basic research into just what role the brain-clogging deposits, made of a sticky substance called amyloid, actually play, said Alzheimer’s Association Vice President Bill Theis.

A Year to Know
　　Johnson predicts that within a year there will be a good indication of whether or not the vaccine will be effective in humans, adding, “If it is, it will be on the market very quickly, I would think."?Alzheimer’s disease afflicts some 4 million Americans and costs $100 billion to treat. It starts with simple forgetfulness, progressing to dementia and then death. The three available drug treatments currently available provide only partial relief for a short time.
　　Alzheimer’s patients"?brains are full of sticky amyloid plaques. It is not clear if the plaques cause Alzheimer’s disease or are a result of it. Regardless, studies show they lead to death of brain cells.
　　The plaques"?main ingredient is beta amyloid, a fragment of a normal body protein that somehow goes awry in Alzheimer’s. Some patients produce too much beta amyloid and others simply do not clear it out of the brain properly.

Amyloid: Immune Stimulus
　　Elan theorized that a vaccine made from beta amyloid would stimulate the immune system to recognize and attack the protein.
　　Indeed, vaccinated mice developed immune system antibodies that traveled to the brain and “tagged"?amyloid plaques. That tagging seems to alert microglial cells, which Dr. Ivan Lieberburg, Elan’s chief medical officer, calls the brain’s “garbage-men,"?to head for the plaques and try to eradicate them. Upon dissection, the brains of vaccinated mice contained no or very small plaques while their unvaccinated littermates had extensive plaques.
　　Another study unveiled at the Alzheimer’s meeting supports Elan’s work. University of Toronto scientists taught mice bred to develop an Alzheimer’s-like disease to swim through a water maze. Over several months, vaccinated mice remembered how to get through the maze far better than unvaccinated mice, promising evidence that the vaccine may affect symptoms, not just plaque.
　　“Imagine what it would mean if you could actually modify the behavior of someone with Alzheimer’s,"?an Elan spokesperson said. “It would be tremendous."?/p>

　　(From ABCNews)