The Alzheimer’s Disease Cooperative Study (ADCS), a federally-established consortium conducting clinical trials on Alzheimer’s disease (AD), will receive $52 million over six years to conduct several new trials, the National Institutes of Health (NIH) announced today. The award is a cooperative agreement between the NIH’s National Institute on Aging (NIA) and the University of California, San Diego (UCSD), which coordinates the consortium of nearly 70 sites in the United States and Canada.

The purpose of the award is to test drugs for their effectiveness in slowing down the progression or treating the symptoms of AD, as well as to investigate new methods for conducting dementia research. Specifically, researchers will focus on possible therapies aimed at affecting the beta amyloid peptide and the tau protein, both involved in the development of AD.

“We have learned a great deal from basic and observational research about how Alzheimer’s and other neurodegenerative diseases develop,” says Richard J. Hodes, M.D., Director of the NIA. “The consortium’s work will translate this knowledge in clinical trials of interventions that target the mechanisms underlying Alzheimer’s disease.”

Among the new studies to be undertaken are:

• Docosahexaenoic Acid (DHA) — This trial will examine whether treatment with DHA, an omega-3 fatty acid found in fish, will slow decline in AD. Observational studies associate high fish consumption with reduced risk of AD in people, and studies in mouse models of AD show that dietary DHA reduces brain levels of beta amyloid, oxidative damage associated with beta amyloid, and neurotoxicity.
• Intravenous Immunoglobulin (IVIg) — There is increased interest in passive immunization strategies against AD. IVIg contains naturally-occurring antibodies against beta amyloid, and preliminary studies have shown that IVIg may improve cognition. In addition, research has demonstrated that IVIg increased levels of anti-beta amyloid antibodies in plasma and promoted clearance of beta amyloid from cerebrospinal fluid. The new ADCS trial will more definitively demonstrate whether IVIg is useful clinically for treating AD.
• Lithium — The biological activity of lithium, which has been shown in animal models to block abnormal changes in tau, has created interest in lithium as a novel treatment for AD. ADCS investigators will undertake a pilot biomarker study to see whether the drug can lower tau and beta amyloid levels in cerebrospinal fluid and be safely tolerated in older AD patients.
• Home-Based Assessment — Older individuals, particularly the very elderly, may have physical, social and health limitations that make it difficult for them to take part in research trials. This study, conducted in people aged 75 and older, will examine the use of mail-in questionnaires, automated telephone technology and computerized data collection to assess cognitive, functional, and other factors in the home environment to see how home-based assessments might be used in primary prevention trials. Such an approach could significantly reduce the cost and increase the feasibility of participation in these long-term, costly clinical trials.

These projects join ongoing ADCS trials testing whether statins and high-dose folate/B6/B12 supplements can slow the clinical signs of AD, as well as a study of valproate to determine whether this drug can either slow decline or help delay the agitation and psychosis that often emerge in AD patients.

Leon Thal, M.D., chair of the Department of Neurosciences at the UCSD School of Medicine and principal investigator of the ADCS, notes that the selection of compounds for testing was enhanced by seeking ideas from the biotechnology sector as well as from individual investigators and the consortium’s members. “We have been able to bring together a larger universe of people studying therapies for Alzheimer’s, and I think this group of studies reflects new thinking in how to approach the disease,” he says.

This ADCS consortium was first established in 1991 as an infrastructure of leading researchers to carry out clinical trials for promising new therapies for AD. Investigators have tested such compounds as vitamin E, the anti-Parkinson’s disease drug selegiline, estrogen, anti-inflammatories and donepezil for their potential in slowing down or preventing cognitive impairment and/or dementia. Recently, positive but limited effects have been shown in slowing the development of dementia with donepezil.

To date, approximately 4,600 people have participated in the ADCS studies. Neil Buckholtz, Ph.D., who leads the federal government’s partnership with the consortium as chief of the Dementias of Aging Branch of the NIA, recognized the efforts of the study participants and their families. “Participating in research takes time and dedication, and the efforts of the participants and their families stand out,” Buckholtz notes. “We are deeply grateful for their help in finding new and better ways to treat and prevent Alzheimer’s disease.” As the new round of trials gets underway, stepped up public participation will be essential for their success, Buckholtz says, and he urges the public to learn more about how to take part in such research. (See information, below)

Alzheimer’s disease affects an estimated 4.5 million people in the U.S. It increases dramatically with age, affecting approximately 40-50 percent of people age 85 and older. The numbers of people with AD are expected to rise dramatically with the aging of the population over the next few decades.

The NIA, one of 27 institutes and centers at the NIH, is part of the U.S. Department of Health and Human Services. It leads the federal effort to support and conduct basic, clinical, and social and behavioral studies on aging generally and AD specifically. NIA supports the Alzheimer’s Disease Education and Referral (ADEAR) Center, which provides information on clinical studies and other research to the public, health professionals, and the media. ADEAR can be contacted toll-free at 1-800-438-4380 or by viewing www.nia.nih.gov/alzheimers.

As the studies mentioned above move forward, more information will be available at the ADEAR website about participation. NIA invites the public to sign up for e-mail alerts, which will let subscribers know when trials begin recruitment and generally when new information about AD is available.

A list of the 35 primary ADCS sites appears on the NIA website at http://www.nia.nih.gov/NewsAndEvents/PressReleases/PR20061017ADCS.htm.

The National Institutes of Health (NIH) — The Nation's Medical Research Agency — includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.