A clinical study involves research using volunteers (also called participants) that is intended to add to medical knowledge. There are two main types of clinical studies: observational studies and clinical trials.
In an observational study, investigators assess health outcomes in groups of participants according to a protocol or research plan. Participants may receive interventions, which can include medical products, such as drugs or devices, or procedures as part of their routine medical care, but participants are not assigned to specific interventions by the investigator (as in a clinical trial). For example, investigators may observe a group of older adults to learn more about the effects of different lifestyles on cardiac health.
Clinical trials are studies of drugs that are still in development or have not yet been approved to treat patients with the specific condition being studied. A drug being studied in a clinical trial is called an investigational drug.
In a clinical trial, a drug is evaluated to determine whether or not it is safe and effective. The drug may be compared with a placebo (a substance not expected to have any real medical effect) or a different treatment.
Clinical trials of drugs provide information about:
Clinical trial results allow the FDA, or local regulatory agency, to make decisions about whether or not a drug should be approved for marketing.
Participants in clinical studies can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research.
By participating in clinical studies, patients help advance medical knowledge and what we know about new drugs. In doing so, clinical trial participants can play an important role in getting new drugs approved for use in treating other patients.
Many times, patients enroll in clinical studies so that they can gain access to new, experimental treatments — especially if all of their other treatment options have failed. Some patients may benefit from participating in a clinical trial if the investigational drug turns out to be effective.
It is important to remember that the main purpose of clinical trials is to study new drugs or new uses of approved drugs, not to treat patients. Often, drugs must be tested under very specific conditions, so not all patients with a given disease will be able to enroll in a clinical trial. In general, each clinical trial has inclusion and exclusion requirements that are intended to make the study more likely to demonstrate the effect of the treatment (such as excluding patients who are taking certain other drugs or who have other complicating disease conditions), or to protect patients by minimizing risks to certain populations (such as pregnant women). Additionally, a clinical trial for a specific drug is typically conducted at a limited number of institutions. Patients who live too far away from a research center may not be able to participate.
Even among patients who do participate in a clinical trial, some may be treated with the investigational drug, and some may be treated with a placebo , often along with existing standard of care, or a different therapy for comparison. Drugs that are being tested in clinical trials may not end up proving to be effective, or they may have unknown, sometimes severe, side effects.
If you are considering participating in a clinical trial, you should carefully read information about the drug trial you are considering and ask questions about exactly what will happen during the trial during a process known as "informed consent." You are entitled to receive detailed information regarding what is known about the drug before you decide to enter a clinical trial, and you must provide a signed informed consent document indicating that you understand what will happen during the clinical trial, before participating.
You should also get advice from your healthcare professional.