Molecular Imaging News
October 13, 2004
NIA Launches Study to Determine Best Neuroimaging Method for Monitoring Alzheimer's Disease
The National Institute on Aging (NIA) is leading a landmark study to find neuroimaging and other methods for monitoring the progression of Alzheimer's disease (AD) aimed at significantly reducing the time and cost of clinical trials.
In the last few decades, great strides have been made in understanding the genetics and biology of Alzheimer's disease. But there is, as yet, no treatment that can delay the onset of AD or halt its progression, and experts predict that the current number of people with AD4.5 millioncould grow to as many as 16 million by 2050 unless new and effective treatments are found. However, clinical trials of promising new medications are slow, expensive, and difficult to conduct, according to Michael Weiner, MD, principal investigator for the study, who spoke today at the AMA's 23rd Annual Science Reporters Conference.
"Brain imaging seems to offer the greatest potential for tracking the progression of AD and simplifying clinical trials. Those of us doing brain imaging research believe we can recognize how the brain changes in normal aging and identify specific changes that are related to AD," said Dr. Weiner, director of the Center for Imaging of Neurodegenerative Disease at the VA Medical Center and professor of medicine, radiology, psychiatry, and neurology at the University of California, San Francisco. "But every lab is doing something a bit different. Some people are using PET (positron emission tomography) and some varying types of MRI (magnetic resonance imaging). What are the best methods; what would make the best standard?"
The Alzheimer's Disease Neuroimaging Initiative has five major goals, according to Dr. Weiner: develop a standard imaging method for clinical trials; improve methods of imaging; determine the optimum methods for acquiring and processing images; validate imaging and biomarker data; and provide a database that will be available to all qualified scientific investigators.
"This initiative is an important step by the government and private partners to come together in the fight against AD," said Richard J. Hodes, MD, director of the NIA. "It significantly advances our commitment to find better and faster ways to test new therapies." The undertaking required to establish a new standard was simply too large, too involved, and too expensive for any one company or university to take on.
The Initiative is being planned as a partnership among the NIA and the National Institute of Biomedical Imaging and Bioengineering at National Institutes of Health (NIH); the Food and Drug Administration; academic investigators; and private partners including pharmaceutical companies and the Institute for the Study of Aging brought together by the Foundation for NIH, with additional participation by the Alzheimer's Association.
The study will enroll 800 people at 45-50 sites over the course of five years: 200 normal elderly people, who will act as controls; 200 people with diagnosed AD; and 400 people with mild cognitive disorder (MCIpeople with MCI are at high risk of developing AD). Everyone will have baseline and periodic brain imaging (either one of two forms of MRI or a PET scan). In addition, blood and urine samples will be collected. Clinical evaluations will also be done to allow researchers to correlate biomarkers with neuropsychological and behavioral data. In addition to Dr. Weiner, this enormous effort will be led by Leon J. Thal, MD, University of California, San Diego; Ronald Petersen, MD, PhD, Mayo Clinic; Clifford Jack, MD, Mayo Clinic; William Jagust, MD, University of California, Berkeley; Arthur Toga, PhD, University of California, Los Angeles; John Trojanowski, MD, University of Pennsylvania, Philadelphia; Laurel Beckett, PhD, University of California, Davis; and Ronald G. Thomas, PhD, University of California, San Diego.
Current clinical trials in AD focus on clinical measures such as changes in memory and the ability to perform tasks of daily living. "Because there is such a huge variability in these measures among individuals, we require lengthy trials with large numbers of people," Dr. Weiner said. "Finding biomarkers should be able to tell us with more sensitivity and specificity which interventions might actually halt progress of the disease, even before clinical signs of the disease appear."
"The advances we have made in genetics, pathology, cell biology and biochemistry have brought us a much greater understanding of the mechanism of Alzheimer's," Dr. Weiner said. "We have a large number of potential medications in the pipeline for slowing progression of the disease. The initiative holds out hope for developing effective medications to prevent the progression and, perhaps, the development of AD."