Frequently Asked Questions About Clinical Trials


Before a new treatment or medication can be prescribed by physicians, it has to be tested thoroughly under supervision of the FDA and other authorities to determine the optimal dosage, the safety information (side effects), and other important information that users and doctors should know. This research is done using a clinical trial. Clinical trials usually include a large number of participants with a medical concern/diagnosis who are followed very closely by medical experts while trying out a new medication.

People with Alzheimer's disease, those with MCI, or those with a family history of Alzheimer's disease, who want to help scientists test possible treatments may be able to take part in clinical trials. Healthy people also can help scientists learn more about the brain and Alzheimer's disease. Many of these studies are being done at NIA-supported Alzheimer's Disease Centers located throughout the United States. These centers carry out a wide range of research, including studies of the causes, diagnosis, treatment, and management of Alzheimer's disease.

The NIA also supports the Alzheimer's Disease Cooperative Study (ADCS), a consortium of researchers at 109 sites in the U.S. and Canada conducting large-scale clinical trials of new approaches to treating and preventing Alzheimer's disease. The ADCS is based at the University of California, San Diego. The NIA maintains the Alzheimer's disease Clinical Trials Database, which lists Alzheimer's disease clinical trials sponsored by the Federal government and private companies.

You also can sign up for e-mail alerts on new clinical trials as they are added to the database. Additional clinical trials information is available at www.clinicaltrials.gov.

With just a small number of FDA approved medications for the treatment of Alzheimer's disease, we recognize the critical need to research new treatment options. Current medications cannot stop Alzheimer's disease. These medications may help prevent some symptoms from getting worse. Current research is aiming to halt the progression of Alzheimer's disease itself or target some of the protein build ups in the brain. Additionally, there is a great need for better ways to diagnosis and treat memory problems earlier.

In order for any new drug to be available in the US, it has to be tested and approved by the FDA for safety and effectiveness. This process often takes years. To get approval, a small group of people try a new medication so researchers can see if it is effective, what dose is optimal, and if there are any side effects.

Individuals who participate in drug studies have a number of benefits:

  • Participants may have the opportunity to try a study medication that is not otherwise available.
  • They receive the benefit of ongoing memory evaluations and follow-ups that may be more thorough and more frequent than what you might expect from regular doctor visits.
  • They also will be in contact with clinicians who specialize in Alzheimer's disease, so they have access to more resources and information than other people might.

All study procedures are paid for by the study sponsor so participants never have to pay anything out of pocket. Depending on the sponsor of a study, participants and study partners may receive compensation for their time and travel while participating in the study.

Not everyone is eligible to participate in a drug study. Each study has different eligibility criteria, but in general, potential participants need to be in good health, have a diagnosis of mild cognitive impairment or Alzheimer's disease, and be on stable doses of their medications for a period of time before enrolling. Each participant must also have a "study partner" who can come to study visits with them and help report changes. The study partner can be a friend or family member, but should be someone who has frequent contact with the participant.

If you or your loved one currently sees one of our physicians, you can discuss potential participation at their next office visit. Otherwise, you can call one of our clinical trial team members and discuss studies that are currently enrolling based on the participant's diagnosis and current cognitive functioning.

Once we find a study you might be interested in, potential participants and their study partners come in for a screening visit. First, we present the informed consent for the study to them. The informed consent is a document that explains the purpose of the study, what is involved in participation, the risks and benefits, and other important information. Then we make sure that a person is eligible for the drug study by performing a number of procedures, including a memory test, physical exam, blood work, and interviews. Some studies may request that you have had a recent CT scan or MRI that supports the diagnosis of Alzheimer's disease. After we collect all the information from these procedures, we can determine whether or not you are eligible to participate in the drug study.

After we know for sure that someone is eligible to participate in a drug study, they will return for study visits for the duration of the study period. How often you have to come to our office for study visits depends on the study. Some studies require study visits more frequently than others.

When you come in for study visits, you can expect to meet with the study coordinator and the research staff, receive your study medication, and have a number of procedures done which may include memory testing, participant and study partner interviews, and blood and urine tests. Some studies may also require intermittent MRI or PET scans during the time you are participating.

A placebo is a substance that is made to look exactly like the study medication, but it has no effect. There is nothing in it that can affect you.

There is a chance that a participant could receive a placebo for during the course of a drug study. In order to know if a study medication works, we have to compare it to a group of patients who are taking a placebo. All participants are randomly put into either the placebo group or in a group who receives the active study medication. During the study, no one knows who is in which group. However, participants can still benefit from the ongoing evaluations and physician contacts. Sometimes studies may feature an extension phase where all individual who complete the original study period are given active medication.

The chance you may receive a placebo in a study varies. You should take this into consideration when selecting a study to participate in.

Yes. The studies usually require that you have been on a medication for a certain period of time, but generally, all the currently FDA-approved medications are allowed. During the study, you will need to stay on the same medications and take the same dosage.

No treatment can stop Alzheimer's disease. However, for some people in the early and middle stages of the disease, the drugs tacrine (Cognex ®), donepezil (Aricept ®), rivastigmine (Exelon ®), or galantamine (Razadyne ®, formerly known as Reminyl ®) may help prevent some symptoms from becoming worse for a limited time. Another drug, memantine (Namenda ®) has been approved to treat moderate to severe Alzheimer's disease, although it also is limited in its effects.

Also, some medicines may help control behavioral symptoms of Alzheimer's disease such as sleeplessness, agitation, wandering, anxiety, and depression. Treating these symptoms often makes patients more comfortable and makes their care easier for caregivers.

The National Institute on Aging (NIA), part of the National Institutes of Health (NIH), is the lead Federal agency for Alzheimer's disease research. Additionally, we work with a number of pharmaceutical companies who are also studying new treatments for memory loss or diagnostic procedures. Some of our current and past pharmaceutical sponsors of our research studies include Pfizer, Eisai, Eli Lilly, Merck, Baxter, Janssen, Bayer, Bristol-Myers Squibb, and many others.

Scientists are testing a number of drugs to see if they prevent Alzheimer's disease, slow the disease, or help reduce symptoms. Some ideas that seem promising turn out to have little or no benefit when they are carefully studied in a clinical trial. Researchers undertake clinical trials to learn whether treatments that appear promising in observational and animal studies actually are safe and effective in people.


Clinical Trials Open to Enrollment


Prevention. Studies are looking earlier into onset and the progression of the disease and are finding that the earlier you treat, the more potential you have for change the course of the progression. New studies are coming out (or will be coming out soon) that are geared towards using medications previously research for treating memory loss as prevention methods in individuals who test positive for being at risk for developing Alzheimer's disease.

Neuroimaging. Scientists are finding that damage to parts of the brain involved in memory, such as the hippocampus, can sometimes be seen on brain scans before symptoms of the disease occur. An NIA public-private partnership— the Alzheimer's disease Neuroimaging Initiative (ADNI)— is a large study that will determine whether magnetic resonance imaging (MRI) and positron emission tomography (PET) scans, or other imaging or biological markers, can see early Alzheimer's disease changes or measure disease progression. The project is designed to help speed clinical trials and find new ways to determine the effectiveness of treatments.

Alzheimer's disease Genetics. The NIA is sponsoring the Alzheimer's disease Genetics Study to learn more about risk factor genes for late onset Alzheimer's disease. To participate in this study, families with two or more living siblings diagnosed with Alzheimer's disease should contact the National Cell Repository for Alzheimer's disease (NCRAD) toll-free at 1-800-526-2839. Information may also be requested through the study's website.

Mild Cognitive Impairment. During the past several years, scientists have focused on a type of memory change called mild cognitive impairment (MCI) which is different from both Alzheimer's disease and normal age-related memory change. People with MCI have ongoing memory problems, but they do not have other losses such as confusion, attention problems, and difficulty with language. The NIA-funded Memory Impairment Study compared donepezil (Aricept), vitamin E, or placebo in participants with MCI to see whether the drugs might delay or prevent progression to Alzheimer's disease. The study found that the group with MCI taking the drug donepezil were at reduced risk of progressing to Alzheimer's disease for the first 18 months of a 3-year study when compared with their counterparts on placebo.

The reduced risk of progressing from MCI to a diagnosis of Alzheimer's disease among participants on donepezil disappeared after 18 months, and by the end of the study, the probability of progressing to Alzheimer's disease was the same in the two groups. Vitamin E had no effect at any time point in the study when compared with placebo.

Inflammation. There is evidence that inflammation in the brain may contribute to Alzheimer's disease damage. Some studies have suggested that drugs such as nonsteroidal anti-inflammatory drugs (NSAIDs) might help slow the progression of Alzheimer's disease, but clinical trials thus far have not demonstrated a benefit from these drugs. A clinical trial studying two of these drugs, rofecoxib (Vioxx) and naproxen (Aleve) showed that they did not delay the progression of Alzheimer's disease in people who already have the disease. Another trial, testing whether the NSAIDs celecoxib (Celebrex) and naproxen could prevent Alzheimer's disease in healthy older people at risk of the disease, has been suspended. However, investigators are continuing to follow the participants and are examining data regarding possible cardiovascular risk. Researchers are continuing to look for ways to test how other anti-inflammatory drugs might affect the development or progression of Alzheimer's disease.

Antioxidants. Several years ago, a clinical trial showed that vitamin E slowed the progress of some consequences of Alzheimer's disease by about 7 months. Additional studies are investigating whether antioxidants— vitamins E and C— can slow Alzheimer's disease. Another clinical trial is examining whether vitamin E and/or selenium supplements can prevent Alzheimer's disease or cognitive decline, and additional studies on other antioxidants are ongoing or being planned.

Ginkgo biloba. Early studies suggested that extracts from the leaves of the ginkgo biloba tree may be of some help in treating Alzheimer's disease symptoms. There is no evidence yet that ginkgo biloba will cure or prevent Alzheimer's disease, but scientists now are trying to find out in a clinical trial whether ginkgo biloba can delay cognitive decline or prevent dementia in older people.

Estrogen. Some studies have suggested that estrogen used by women to treat the symptoms of menopause also protects the brain. Experts also wondered whether using estrogen could reduce the risk of Alzheimer's disease or slow the disease. Clinical trials to test estrogen, however, have not shown that estrogen can slow the progression of already diagnosed Alzheimer's disease. One study found that women over the age of 65 who used estrogen with a progestin were at greater risk of dementia, including Alzheimer's disease, and that older women using only estrogen could also increase their chance of developing dementia.

Scientists believe that more research is needed to find out if estrogen may play some role in Alzheimer's disease. They would like to know whether starting estrogen therapy around the time of menopause, rather than at age 65 or older, will protect memory or prevent Alzheimer's disease.