Over the last 15 years, scientists have made enormous strides in understanding how Alzheimer’s disease affects the brain. Many of these recent insights point toward promising new strategies for treatment, prevention and diagnosis.

Following successful laboratory work or animal studies, new treatments must undergo clinical studies (testing in human volunteers, also called clinical trials). More than 100 clinical studies are now recruiting participants with and without Alzheimer’s disease, related diseases or memory loss to help test these exciting new approaches.

Reasons to consider participating

You can make a difference! Clinical studies are the engine that powers medical progress. Scientists work constantly to find better ways to treat diseases. Improved treatments can never become a reality without testing in human volunteers. No one ever chooses to become ill, but anyone can consider helping to advance knowledge about an illness affecting them or someone close to them.

There is reason for optimism about experimental treatments. No investigational treatment advances to clinical testing unless there is strong evidence indicating it will be as good or better than currently available therapies

Every study matters. Every clinical study contributes valuable knowledge, whether or not the treatment works as hoped.

Participants receive a high standard of care. All participants receive regular care related to the study and opportunities to talk to study staff. Research shows that people involved in studies tend to do somewhat better than people in a similar stage of their disease who are not enrolled, regardless of whether the experimental treatment works. Scientists believe this advantage may be due to the general high quality of care provided during clinical studies.

How clinical trials work

Studies proceed in “phases”

The U.S. Food and Drug Administration (FDA) has established a rigorous sequence of testing for experimental drugs. The system gradually builds evidence for a drug’s effectiveness and determines that a drug has an acceptable “safety profile” (that is, the risks associated with its use are reasonable, given its potential benefit). Experimental drugs must perform well enough in each phase to be allowed to progress to the next one.

• Preclinical studies in laboratories establish a scientific basis for believing a drug is reasonably safe and may be effective.

• Phase I trials, the first stage of human testing, typically enroll fewer than 100 volunteers. These studies are primarily concerned with assessing risks and side effects associated with a drug.

• Phase II trials enroll up to a few hundred volunteers with the condition the drug is designed to treat. These studies provide further information about safety and focus on determining the best dose of a drug. Scientists also watch for signs of effectiveness, but Phase II trials are generally too small to provide clear evidence about benefit.

• Phase III trials enroll several hundred to thousands of volunteers, often at multiple study sites nationwide. They provide the chief evidence for safety and effectiveness that the FDA will consider in deciding whether to approve a drug.

• Phase IV trials, also called post-marketing studies, are often required by FDA after a drug is approved. The trial sponsor must monitor the health of individuals taking the drug to gain further insight into its long-term safety and effectiveness and the best way to use it

Designed for accuracy

Scientists have learned that people can sometimes feel better, and even have improved results on medical tests, just because they believe a treatment is helping them. Doctors can also convince themselves a treatment is working because they care about their patients and want to help them get better.

There are two main strategies to reduce the likelihood that hopes and beliefs will affect the outcome of clinical studies:

1) Trials are “placebo-controlled.” This means that some study participants are randomly chosen by a computer to receive the experimental treatment and some receive a “placebo” (an inactive, look-alike treatment).

2) Trials are “double-blinded.” This means that both participants and study staff are “blind” (unaware) about who is getting the drug and who is getting the placebo.

Some studies are designed so the group of participants getting the treatment is larger than the group receiving the placebo. And some studies can be designed so all participants get the treatment for part of the study.

Safety behind the scenes

Although participants and study staff don’t know who’s getting the drug and who’s getting the placebo, most trials have a separate, independent Data Safety and Monitoring Committee with access to this information. Committee members regularly analyze data behind the scenes and step in if they notice any worrisome patterns of serious side effects in drug recipients.

Informed consent

Participating in research is a big step. Informed consent is the process of learning key facts about a study before deciding whether to volunteer. The FDA requires potential participants to be given complete information about the study in writing. Study staff also meet personally with each potential participant to explain risks and possible benefits and answer any questions. People who decide to join the study must sign the informed consent form.

Individuals who are invited to participate in a study are not required to do so. Participants are also free to leave a study at any time.

Matching participants to studies

Enrolling the right participants helps researchers maximize the likelihood of accurately measuring the effect of an experimental treatment. Some drugs, like antibiotics for an infection, have an obvious effect that is easy to detect.

It is often more challenging to assess the impact of drugs for chronic, serious diseases, including Alzheimer’s and related diseases. To eliminate certain factors that make it harder to assess a treatment, researchers define “inclusion and exclusion criteria” for each clinical study. Examples of these criteria include:

• Limiting participants to a certain age range

• Requiring participants to be in a certain stage of the disease

• Not allowing health conditions other than the one being studied

• Not permitting use of certain other medications

• Requiring participation of a caregiver or “study partner”

How to find a study near you

If you would like to consider participating in research, please see our Clinical Trials Index.

More information:

The U.S. Food and Drug Administration (FDA) provides extensive information about clinical studies and participating in research. Some items are available in Spanish as well as English. 
Go to www.fda.gov