Participating in Clinical Trials: What You Need to Know

By Christine Weber, Ph.D. and Mary Sano, Ph.D., Gertrude H. Sergievsky Center, Columbia University

Clinical trials evaluate treatments to determine if they can improve, delay or prevent a disease or a symptom. Many clinical trials are being conducted to find treatments and preventions for Alzheimer’s disease and for memory loss among older people. Clinical trials are conducted with new drugs that have been discovered in the laboratory or in nature and with known drugs to see if they can help a new disease or symptom. Participating in clinical trials offers many opportunities to learn more about treatments and disease. However, it is important to have a good understanding of the risks and benefits of any study when making a decision to participate.

What is a clinical trial?

A clinical trial is a study with the purpose of determining whether a treatment improves a clinical condition or a disease. In fact, a clinical trial is an "experiment" which is the most rigorous type of study. This means the study is designed to test the specific idea that a treatment is effective and safe. To insure confidence in the results of the study, clinical trials will randomly assign volunteers to receive a treatment or an alternative. The alternative may be a pill, which has no active ingredient, known as a placebo, or it may be a comparison treatment. For Alzheimer’s disease and memory loss, most studies compare one or two treatments to placebo, since so few treatments for these problems exist. By using random assignment and by comparing the treatment group to another comparison group we have great confidence that the effects we see are due to the treatment and not just to other factors.

Who are included in clinical trials?

Each clinical trial has a set of inclusion and exclusion rules. These are designed to insure that the study will be able to measure the effectiveness of the drug and to insure that the study is conducted in the safest way. For example, in a treatment trial of Alzheimer’s disease, inclusion might be limited to people who have a certain stage of the disease in order to insure that the participants are impaired enough to observe a benefit but not so impaired that the benefit of a treatment is not measurable. A clinical trial may exclude people with certain medical conditions or those taking other medication, to avoid any serious safety problems or to insure that the efficacy can be measured. For example, in a clinical trial of Alzheimer’s disease, participants who also have a stroke are excluded because the benefit provided by the drug may be masked by the problems caused by the stroke.

What tests and procedures are involved in a clinical trial?

The procedures and tests used in the clinical trial have two purposes. The first is to determine if a person is eligible. That means some tests must be conducted to be sure that a certain disease is present or that other interfering conditions are absent. Some medical tests, such as blood tests may be done to determine general health and to avoid unnecessary risks to the participant who may have silent or undiagnosed conditions they are not aware of.

The other reason for tests and procedures is to measure the effect of treatment. For clinical trials of memory loss and Alzheimer’s disease the most common types of tests or procedures measure memory and thinking. These tests are usually given before, during and after the treatment to determine if the treatment can improve the performance compared to the comparison group. Tests may be repeated several times during the course of the study to insure a stable measure of the treatment effect. Clinical trials may also measure biological or medical conditions with laboratory tests, taking blood samples or blood pressure, or conducting physical or neurological examinations. For example in Alzheimer’s disease, many treatments are designed to work by reducing a protein called amyloid in the brain. Some studies may take a blood sample before and after treatment to determine if amyloid or other associated biological substances are reduced. Some tests are also done to identify groups of individuals who might be most responsive to treatment. For example, genetic testing may be done by taking a blood sample to determine if a certain subgroup may be more likely to benefit or have a bigger response to the treatment.

What are the benefits of a clinical trial and why do people participate?

Many individuals question why they should consider participating in a clinical trial, what it is like to participate in a clinical trial and what they should expect. An individual’s decision to enter a clinical trial is a very personal one and there are a variety of reasons for considering taking part in a study. Having hope for a future cure, feeling better and contributing to research and society are some personal reasons participants enter trials. Participants who enter clinical trials also receive new treatments before they are readily available to nonparticipants.

In general, most individuals participating in clinical trials report a positive experience. A survey conducted by CenterWatch found that 52% of individuals who participated in a clinical trial rated their experience as "Excellent," 34% rated their experience as "Good," while less than 4% of subjects reported having a "Poor" experience. When asked about the quality of care they received 89% of individuals reported "Good to Excellent," while only 2% rated the quality of care they received as "Poor".

One report found that clinical trial participants with Alzheimer’s disease were able to remain at home, and not in a nursing home longer than a comparison group who did not participate in trials. This was true even for those who received placebo, suggesting that there may be a benefit from the added support and attention received in clinical trials.

What are the risks of participation and how does a clinical trial protect against them?

There may be both small and large risks associated with clinical trials. Small risks might be discomfort associated with laboratory tests or inconvenience associated with frequent visits to participate. Other risks such as side effects from the treatments may also exist. With new treatments there may be unknown risks or side effects.

One protection is by providing complete information about the study. All of these risks are carefully and completely described in a consent form, which all participants must sign before beginning a clinical trial. Clinical trials are reviewed by an Institutional Review Board (IRB). An IRB is composed of professional and community individuals who insure that the study reports all of the risks and benefits in the consent form in a way that is easy to understand. IRBs are key aspects of clinical trials and exist to insure that clinical procedures, staffing, and conduct are ethical and safe for participants. An IRB must approve a clinical trial protocol before any subject is entered in the study. Participants should fully review the Consent Form before they sign it and discuss any questions they may have with the investigator conducting the study. It is important to know that a participant may withdraw from a clinical trial at any time.

Any side effects that occur should be reported to the study investigator who will address them and take appropriate medical action. In addition, side effects are reported to the Institutional Review Board who will make decisions to improve safety.

Are there special considerations for participation in trials for Alzheimer’s Disease or memory loss?

One very important issue that arises when a cognitively impaired person enters a clinical trial is whether they are able to fully understand and provide consent and are able to follow the study procedures. For these individuals many clinical trials require that they have an advocate. The advocate is usually a family member or close friend who knows the participant well. This individual can assist in making the decisions that are in the best interest of the participant and can also assist in collecting information about the participant’s memory and functioning. The advocate may also help the participant to remember to take the treatment and most importantly, will insure that the participant follows the study procedures, attends appointments, and reports problems if they occur. The role of the advocate requires a significant amount of time and commitment to complete these activities. However, it is very important to insure the safety of the participant.

Who should participate in clinical trials?

Participants and their family and friends must evaluate their own needs and concerns. For some individuals the opportunity to participate in new treatments is very important and holds great promise. Some families may find the added attention provided by clinical trial staff to be an important support network. Others may find the side effects associated with treatment or the time and trouble associated with making many visits and insuring that the participant takes medication to be a serious burden. These are personal decisions that are important and must be made by each individual. When the potential benefits outweigh the risks, participation in a clinical trial may be the right choice.

Where can I find a listing of clinical trials?

There are several sites on the Internet that list clinical trials. Individuals may look to such sites as The Alzheimer’s Disease Education and Referral Center that is included in ElderCare Online's Medical Research Assistant. This site contains information about clinical trials as well as educational material pertaining to memory loss and Alzheimer’s Disease. Other sites that list a wide variety of studies include and

Christine Weber, Ph.D. and Mary Sano, Ph.D.,
Gertrude H. Sergievsky Center
Columbia University

Available from ElderCare Online™               1999 Prism Innovations, Inc.