What Are Clinical Trials?

Human clinical trials are research studies that evaluate the effects of investigational medical interventions on health outcomes. These trials involve volunteers of all ages who participate to test various treatments, including drugs, devices, biological products, surgical procedures, behavioral treatments, and preventive care.

Clinical trials aim to answer specific health questions and contribute to scientific knowledge of disease states and interventions. Each trial is carefully designed, reviewed, and approved before beginning. Ethical and regulatory standards ensure trial participant safety and data integrity throughout the trial.

There are four phases of clinical trial research:

• Phase I: These studies test new drugs for the first time in a small group of people – trial participants, healthy volunteers or patients. Researchers evaluate safe dose ranges, tolerability, and identify side effects.
• Phase II: Treatments found safe in Phase I move to a larger group of trial participants. Researchers monitor for adverse effects and optimal dose range.
• Phase III: Conducted on larger populations of trial participants across different regions and countries to fully characterize the safety and efficacy of the intervention, Phase III trials often precede country approval of a new treatment.
• Phase IV: These studies occur after country approval and involve further testing in a wide population over a longer time.

Why Are Clinical Trials Done?

Human clinical trials help assess the safety and efficacy of new interventions, develop new indications, and play a crucial role in advancing medical knowledge and improving patient care. Trials may also investigate an approved drug or device for long-term effects in a general population. Without trials, we lack sufficient evidence to know if a treatment works or is safe. Clinical trials help identify better health outcomes and safer interventions.

Who Should Consider Clinical Trials and Why?

Human clinical trials are pivotal in the advancement of medical science and patient care. Participation in these trials is not only a personal decision but also a contribution to the collective knowledge of healthcare.

Some people participate in clinical trials because standard available/approved treatment options have not worked for them, and a clinical trial provides access to new treatments under investigation. Other participants may be healthy volunteers who wish to contribute to the betterment of medical treatments and outcomes for future patients.

Ensuring people from diverse backgrounds join clinical trials is crucial. Participants should represent the patients who will use the products.

All clinical trials have eligibility criteria based on factors such as age, sex, disease type, previous or current treatment, and other medical conditions. Prospective trial participants must meet the eligibility criteria in order to participate in the trial.

Clinical trials are conducted under stringent ethical standards and regulatory oversight to safeguard a trial participant’s rights, safety, and well-being. Participation in a clinical trial is a substantive decision that should be made in consultation with healthcare providers, considering the potential risks and benefits.

Learn more about clinical trial participation at NIH Clinical Research Trials and You.