Clinical trials are a set of procedures in medical research and drug development that are conducted to allow safety (or more specifically, information about adverse drug reactions and adverse effects of other treatments) and efficacy data to be collected for health interventions (e.g., drugs, diagnostics, devices, therapy protocols).
Research on treatments starts in the laboratory where scientists work to identify the processes involved. These are called Pre-Clinical studies. Clinical trials begin with Phase I trials, which test the treatment on a small number of people for safety and best dose. Phase II involves several hundred subjects to test for effectiveness.
Phase III studies involve randomized and blind testing in several hundred to several thousand patients. This large-scale testing, which can last several years, provides the pharmaceutical company and the FDA with a more thorough understanding of the effectiveness of the drug or device, the benefits and the range of possible adverse reactions. Phase IV studies, often called Post Marketing Surveillance Trials, are conducted after a drug or device has been approved for consumer sale.
Not all clinical trials study treatments. Even though we talk about research studies as if they are all about treatments, many clinical trials look at new ways to detect, diagnose, or learn the extent of disease. Some even look at ways to prevent the disease from happening in the first place. Even among clinical trials that do study treatments, not all of them study drugs.
The two classic types of studies in biomedical research are controlled (also called experimental or intervention) and observational (also called epidemiological). There are advantages and disadvantages to each, and an awareness of these differences makes for a savvier consumer of public health information.
Clinical trials are not treatments, but experiments. Although it's possible that benefit may be derived from participating in a clinical trial, it's also possible that no benefit — or even harm — may occur. Therefore, the decision about whether to participate in a clinical trial requires careful consideration.
In a single-blind study, patients do not know whether they are in the treatment group or the control group. In a double-blind study, neither the patients nor their doctors know which group they are in. The purpose of blinded studies is to make sure the results are not biased by anyone's hopes for a certain treatment.
Each clinical trial is also watched closely by an institutional review board (IRB). The IRB reviews the trial to be sure that it is ethical and that the rights of people who take part are protected. ...IRB Members include doctors and people from other professions, such as ethical experts, teachers and religious leaders. Throughout the trial, doctors make reports to the FDA and the IRB. The FDA and/or the IRB can stop a trial at any time to protect the people in it.
The people running the study are required to get written, informed consent. ... Consent forms are not all the same, but they should include the following: The reason for the study (what the researchers hope to find out), Who is eligible to take part in the study, What is known about the new type of treatment, The possible risks and benefits of the new treatment (based on what is known so far), etc.
Who can participate in a clinical trial? To qualify for a particular study, participants must meet a carefully defined set of criteria. These usually relate to age and gender, disease type and stage, and the types of treatments they have already received.
Drug and device testing begins with extensive laboratory research which can involve years of experiments in animals and human cells. If the initial laboratory research is successful, researches send the data to the Food and Drug Administration (FDA) for approval to continue research and testing in humans. Once approved, human testing of experimental drugs and devices can begin and is typically conducted in four phases.