What is a Clinical Trial?

A clinical trial is a study in which volunteers help researchers answer questions about human health and treating disease. Clinical trials may test drugs, medical devices or other treatment interventions to determine whether they are safe and effective for human use. Clinical trials are highly monitored and regulated to ensure that the rights and well-being of research participants are always taken into account.

Who Can Participate in a Clinical Trial?

Some studies may seek volunteers with a certain disease or condition, while others seek healthy volunteers to participate in their projects. Volunteers of all racial and ethnic backgrounds, ages and gender identities are encouraged to see if they are eligible to take part in clinical research studies. Each clinical trial is structured around a specific protocol that outlines how the study should be conducted. Within each protocol are inclusion and exclusion criteria that state what would allow someone to take part in the study, or be excluded from participating.

Why Should I Participate in a Clinical Trial?

Some people take part in clinical trials to gain early access to the latest treatment options in development, while others take part in clinical trials to have an impact on the discovery of new treatment options for others. Whatever your reason for volunteering to be a participant in a clinical trial, and whatever the outcome of the study you take part in is, you are making a difference by participating in the process.

What are the Different Types of Clinical Research?

There are many kinds of clinical research studies. Different research methods and study designs may be used depending on the study question researchers are trying to answer. Below are a few types of clinical research studies that are performed by researchers at Mass General:

  • Behavioral Studies examine the connection between human behavior and health Clinical Trials are designed to test therapeutic interventions to find new—or new uses for—medicines, devices, or other treatments for human illnesses
  • Diagnostic Studies help to find better ways to diagnose conditions
  • Epidemiologic Research seeks to examine patterns in illnesses across populations Genetic Research looks to determine the connections between genes, patients and their illnesses
  • Outcomes Research looks to find the most effective and cost-efficient treatments to address human illnesses
  • Prevention Studies seek to determine ways to prevent human illness, or to prevent illness from recurring
  • Prevention Centered Outcomes Research (PCOR) provides the opportunity for patient and caregiver voices to form the assessment of health care options
  • Quality-of-Life Studies examine ways to improve the way those with chronic illnesses integrate the care of their illness into their daily lives
  • Screening Studies help to find new ways to determine if someone has a certain illness or disorder

What are the Phases of Clinical Research?

Clinical trials are conducted in a series of progressive phases that are designed to determine whether a treatment should move forward in the testing and approval process.

Drug trials are generally conducted in the following phases:

Pre-clinical Research

Before any medical treatment is tested in humans, it must first be studied in animals to show it is safe enough to be tested in people.

Phase I Trials

Phase I trials are small-scale studies (typically consisting of 20-80 participants who are often healthy volunteers) that take a preliminary look at how a drug works in the human body, what dosages are safe and what side effects might occur.

Phase II Trials

Phase II Trials are medium-scale studies (typically hundreds of participants with the disease or condition being studied) that take a first look at how effective a drug might be and further examine safety, efficacy and side effects that might occur.

Phase III Trials

Phase III Trials are large-scale studies (typically thousands of participants with the disease or condition being studied) that confirm side effects, safety and efficacy, evaluate the overall risks and benefits of the drug being studied, and begin identifying how it might be used by the general population.

Phase IV Trials

Phase IV trials occur after a drug has been approved by the Food and Drug Association and provide further information about the risks and benefits of a drug and how it might be best used by the general population.

What are the Benefits and Risks of Clinical Trials?

Each clinical research study has risks and benefits, which are detailed in the study's informed consent document. Some clinical trials may be relatively risk-free, while others may have considerable risk or burdens that they place upon study participants. Some studies may benefit study participants by providing them access to experimental treatments or care that they might not otherwise be able to access. Other studies may have no direct benefit to participants.

It is important to know that by taking part in a clinical research study you are helping inform the creation of new treatment options for others--today and in the future. It is important to speak with study staff about any questions or concerns you might have about the potential risks involved in taking part in a clinical research study.

What is Informed Consent?

Informed consent is a process that ensures that research participants are fully informed about the purpose, risks, benefits, procedures and duration of a trial as well as the requirements of those participating in a clinical research study. Study staff must review a written informed consent document with potential study participants and /or their designees before they decide to sign the informed consent document.

After signing the document, all participants must be continuously informed of any changes to the study that might impact their participation. Taking part in a clinical research study is a voluntary experience. Participants are encouraged to ask questions and may withdraw from study participation at any time. Return to clinical research homepage