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Clinical Trials

In October of 1991, the National Institute of Aging created the Alzheimer’s Disease Cooperative Study (ADCS), under the leadership of our former director, Dr. Leon Thal. The ADCS coordinates clinical trials across the nation to test new medications designed to improve thinking skills and daily functioning, slow the rate of decline, or delay the onset of Alzheimer’s’ disease. The UCSD Shiley-Marcos ADRC is one of 35 nationwide university medical centers designated to carry out these clinical trials. As such, our research participants may be among the first to benefit from potentially promising new treatments.

If you would like to learn more about research in general, the National Institutes of Health (NIH), National Institute on Aging (NIA) and the Federal Drug Administration (FDA) have produced many informative articles, books and fact sheets about research practice. The following links are a few examples:


What is a clinical trial?

Before any new medication or medical procedure can become available to the general public, it must undergo a series of lengthy and rigorous tests, under the oversight of the Food and Drug Administration (FDA). These tests move through a series of phases that correspond to the degree of testing that has been undertaken thus far. For more information read the frequently asked questions on the website by clicking here.

According to clinical, clinical trials are biomedical or health-related research studies in human beings that follow a pre-defined protocol. includes both interventional and observational types of studies. Interventional studies are those in which the research subjects are assigned by the investigator to a treatment or other intervention, and their outcomes are measured. Observational studies are those in which individuals are observed and their outcomes are measured by the investigators.

Why participate in clinical trials?

*click here to read the new ADEAR fact sheet about participating in research

Participants in clinical trials and their family members can:

(1) Gain access to new investigational treatments before they are available in the clinical setting

(2) Have access to clinicians and researchers who are on the cutting edge of their field of study

(3) Simultaneously help others, including future generations, by contributing to medical research

Who qualifies to participate in clinical trials?

Before joining a clinical trial, a participant must qualify for the study. All clinical trials have guidelines about who can participate. Using inclusion/exclusion criteria is an important principle of medical research that helps to produce reliable results. The factors that allow someone to participate in a clinical trial are called "inclusion criteria" and those that disallow someone from participating are called "exclusion criteria". These criteria are based on such factors as age, gender, the type and stage of a disease, previous treatment history, and other medical conditions.

Is it safe to participate in clinical trials?

Clinical research studies are conducted in strict accordance with research plans (protocols) that have been developed by a team of research scientists and physicians and then reviewed by the FDA along with an Institutional Review Board (IRB) that represents the public interest. Once a study has begun, its progress is closely monitored by each of these groups.

Participants’ physical health and cognitive status are evaluated regularly over the course of the study to monitor effectiveness and safety of the medication. Participants have the right to withdraw from the study at any time, and they can be withdrawn by the investigator if it is in their best interest to do so.

Every clinical trial in the U.S. must be approved and monitored by an Institutional Review Board (IRB). The role of the IRB is that of participant advocate and their responsibility is to weigh the study participants’ possible risks versus potential benefits. An IRB by definition is an appropriately constituted group that has been formally designated to review and monitor biomedical research involving human subjects. All institutions that conduct or support biomedical research involving people must, by federal regulation, have an IRB that initially approves and periodically reviews the research.

What are the phases of clinical trials?

Clinical trials are conducted in phases. The trials at each phase have a different purpose, are conducted on a varying number of participants and type of participant (healthy controls vs. persons with disease), and help scientists answer different questions:

Phase I trials

Researchers test an experimental drug or treatment in a small group of healthy individuals (20-80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.

Phase II trials

The experimental study drug or treatment is given to a larger group of people (100-300) who are afflicted with the disease or condition for which the drug was developed. These studies help determine if the drug is effective and to further evaluate its safety.

Phase III trials

The third and last pre-approval round of testing of a drug is conducted on large populations (1,000-3,000) of afflicted patients. In phase III studies, testing continues to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the experimental drug or treatment to be used safely. The results of these trials usually provide the information that is include in the package insert and labeling.

Phase IV trials

After a drug has been FDA approved, these post marketing studies are used to compare a drug to a competitor, explore additional patient populations, or to further study any adverse events.