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Some encouraging Alzheimer鈥檚 news from Sweden: a vaccine called CAD106 appears to be safe and ramps up the body鈥檚 immune system against a protein likely involved in Alzheimer鈥檚. The hope is that this vaccine will slow the progression of Alzheimer鈥檚 disease, and possibly even stop it.

The vaccine is designed to activate the body鈥檚 immune system against beta amyloid, a protein fragment that forms deposits called amyloid plaques between nerve cells in the brain. While it鈥檚 unclear if beta amyloid plaques cause Alzheimer鈥檚 or are a result of it, scientists do know that the plaques are an important biomarker of the disease. Some researchers believe that beta amyloid plaques interfere with communication between nerve cells or somehow inhibit processes needed to keep brain cells alive.

鈥淭wenty-five years ago,鈥� says Dr. Anthony L. Komaroff, professor of medicine at Harvard Medical School, 鈥渨e knew very little about what caused Alzheimer鈥檚 disease and therefore how it might be prevented and treated. A lot of people were hopeless. We knew that we could see certain microscopic abnormalities in the brains of people with Alzheimer鈥檚 disease, called plaques and tangles. And we knew some of the chemicals inside the plaques and tangles. But we didn鈥檛 know if they caused the disease, and whether targeting them would help people with the disease.鈥�

This vaccine work may help answer those questions.

Safety first

In the vaccine study, , researchers from the Karolinska Institute gave 58 men and women with mild-to-moderate Alzheimer鈥檚 disease injections of CAD106 or a placebo and followed them for three years. Three-quarters of those who received CAD106 developed antibodies against beta amyloid protein. Virtually all of them鈥攊ncluding those getting the placebo鈥攔eported one or more side effects, ranging from inflammation of the nose and throat to headache, muscle pain, and fatigue.

None, though, developed meningoencephalitis, an inflammation of brain tissue. That鈥檚 important because a trial of an earlier vaccine called AN1792 was abruptly stopped when 6% of those getting the vaccine developed meningoencephalitis. That vaccine apparently triggered a response among certain white blood cells that wound up attacking healthy brain tissue. CAD106, in comparison, targets only the beta amyloid proteins.

The next step in the development of CAD106 is a larger clinical trial to confirm the vaccine鈥檚 safety and to see if it is effective at slowing the relentless progression of Alzheimer鈥檚 disease.

鈥淚t鈥檚 much too early to say whether this particular vaccine will prove to be a valuable treatment in Alzheimer鈥檚 disease,鈥� Dr. Komaroff says. 鈥淣evertheless, in contrast to 25 years ago, today there is a lot of evidence that beta amyloid is one important cause of Alzheimer鈥檚 disease, and that targeting beta amyloid with drugs and vaccines may bring benefits. Because of biomedical research, today we have real reason for hope.鈥�

Several other Alzheimer鈥檚 vaccines that target the beta amyloid protein are also being tested in clinical trials. Another effort moving forward includes an insulin-based nasal spray, which has shown promise in repairing damaged brain tissue involved in memory and cognition. The Obama administration鈥檚 , which was released last month, calls for $7.9 million in funding for this spray.