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Clinical Trials Explained

Clinical research is a branch of medical research that determines the safety and effectiveness of medical, surgical, or behavioral intervention for a disease or other health-related issue. In this post, we'll be breaking down one of the most essential types of clinical research, clinical trials.


What is a clinical trial?

A clinical trial is a specific type of medical research involving human volunteers focused on evaluating the effectiveness and safety of medical and surgical treatments.

Treatments evaluated in clinical trials include:

  • Medical devices

  • Surgical procedures

  • Behavioral changes (ex., smoking cessation, dietary change, exercise)

  • Vaccines

  • Drugs (for both prevention & treatment of disease)

  • Diagnostic tests (​​methods of early detection of a particular disease before a person has symptoms)

Clinical trials are often conducted to determine if a new treatment is more effective than an existing treatment and if it has more (or less) side effects than the standard treatment.

For example, a potential drug or treatment may be given to patients with hypertension (high blood pressure) to determine whether it effectively and safely decreases blood pressure.


How do clinical trials work?

The Clinical Trial Protocol

Clinical trials follow a specific study plan called a protocol. The protocol describes the objectives, design, and methods of the study, including:

  • The types of patients who may enter the study

  • The schedules of tests and procedures

  • The drugs involved

  • The dosages, or amount of the drug

  • The length of the study

  • What the researchers hope to learn from the study.

Phases of a Clinical Trial

There are four phases of clinical trials that new treatments must successfully advance through to confirm their safety and efficacy before the FDA will allow the treatment to be marketed to the public. Each phase involves an increasing number of patients.

Phase I

  • Phase I trials test the new treatment on a small number of healthy participants (20 to 80 individuals) to evaluate its safety, side effects, and the correct dosage to be used in Phase II.

  • Phase I clinical trials are the most critical phase for diversity because this is when the working dose is determined and side effects identified.

  • If African-Americans and other minority populations are not included in this phase, differences in the treatment's dosing and effectiveness due to race and ethnicity will not be identified or considered before drug approval.

Phase II

  • Phase II trials will usually involve 100-300 participants.

  • These trials aim to determine how well the drug or intervention works in people who have the targeted disease or condition and can last for several years.

  • As always, the researchers continue to monitor safety, including side effects.

Phase III

  • Phase III trials aim to expand the information about a new treatment’s safety and effectiveness (efficacy).

  • These trials study the drug or treatment in different populations at different dosages, sometimes using the drug in combination with other drugs.

  • These are much larger trials conducted in several hundred to several thousand people.

  • If the treatment successfully advances through this phase and the results are favorable, the experimental drug or device will be approved by the FDA.

Phase IV

  • Phase IV trials are conducted after a treatment has received FDA approval and is being used by physicians to treat patients with the target disease or condition.

  • The treatment’s safety and effectiveness are monitored in a large and diverse population of people.

  • This longer period of follow-up will sometimes identify side effects that become evident only with the passage of time.

Who conducts clinical trials?

Clinical trials are led by a principal investigator (PI), usually a medical doctor. They also have a research team typically consisting of doctors, nurses, and other health care professionals.

Research team members may vary by study site, type, design, and purpose. However, the responsibilities assigned to members typically include the following:

  • Screening for potential study participants

  • Determining eligibility for participation

  • Coordinating the schedule of tests for patients

  • Preparing documents for submission to institutional review boards (IRBs)

  • Filing amendments

  • Submitting safety data

  • Patient Education

  • Obtaining informed consent

  • Assessing potential side effects

Common Clinical Research Team Members and Responsibilities

Principal Investigator (PI)

​Leader of the clinical research team, responsible for oversight of clinical trials

Clinical Research Coordinator (CRC)

Work with the PI to manage the day-to-day activities of a research study

Study Physician(s)

Treat patients according to the clinical trial protocol, evaluate and record patient responses, and document side effects

Clinical research nurse (CRN)

Help coordinate the day-to-day management of a trial, including patient education, compliance, and follow-up

Clinical Trial Sponsors

Clinical trial sponsors are people, institutions, companies, government agencies, or other organizations that initiate, oversee, or finance a clinical trial. The trial sponsor does not actually conduct the research, they provide the resources needed to ensure the success of the study. Common trial sponsors include pharmaceutical companies, doctors or other health care providers, the National Institutes of Health, and the U.S. Department of Veterans Affairs.

Where do clinical trials take place?

The location, or site, of a clinical trial, depends on who is conducting the study. In most cases, clinical trials take place in hospitals, universities, community clinics, or doctors’ offices.


Who participates in clinical trials?

Both healthy volunteers and patient volunteers with the disease or condition of interest can participate in clinical trials. Healthy volunteers are usually needed for Phase I clinical trials, which test the treatment on a small number of volunteers (20 to 80 individuals) to evaluate its safety, side effects, and the correct dosage. Participation is always voluntary, and participants have the right to leave a study at any time.

Why do people participate?

Clinical trials provide patients with another treatment option when standard treatments have failed.

Some common reasons people choose to participate in clinical trials include:

  • None of the standard (approved) treatment options have worked for them

  • To contribute to the advancement of medical knowledge

Watch this video by the Mayo Clinic to learn more about the Clinical Trial Journey.


Why is clinical research so important for the advancement of health care?

Clinical research is crucial for advancing medical knowledge. Without this valuable research, we would not have the breakthroughs in health and medicine that we do today. Clinical research allows doctors and scientists to better understand diseases and identify new, more effective methods of detection, diagnosis, treatment, and prevention—all of which ensure that patients receive the highest quality care possible.

Clinical trials provide the answers needed to:
  • Discover drugs that improve people's lives (antibiotics, vaccines, insulin, etc.)

  • Create new diagnostic procedures (ex., X-rays, MRIs) to enhance the detection of diseases

  • Improve the way doctors diagnose, treat, and prevent diseases

Discoveries made through clinical research help improve the health of current and future generations. Today’s most advanced medical treatments and devices, like robotic surgical platforms, wireless glucose monitors, and insulin pumps, would not exist without clinical trials. This is how the science of medicine evolves. However, clinical research must include representative numbers of patients from minority populations to provide accurate conclusions on a new treatment's potential side effects and effectiveness in ALL population segments. Thus, minority populations must participate in clinical research and clinical trials to reap the benefits of improved quality of life and longevity.

Interested in getting involved?

Clinical Diversity Solutions is the bridge of trust between patients of color and ethical medical research. Communities of color deserve access to the newest medical treatments, expert medical care, and the health benefits that come with participating in clinical trials.

Help us advocate for increased representation of communities of color in clinical research by completing our confidential survey about personal opinions on medical research and treatment.

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