A clinical trial is a study of a medical treatment in human subjects. The medical treatment can be a drug; a surgical device such as an artificial hip; a medical device such as an insulin pump; or a surgical technique. The purpose of a clinical trial is to answer questions about safety and effectiveness. We use them to determine whether we are using the best treatments or to help the Food and Drug Administration (FDA) determine whether or not to approve a treatment for general use.

Phase II Study The clinical administration of a new drug to a limited number of patients for a short period of time to determine the drug' safety and benefit in treating or preventing disease.

Phase III Study The administration of a new drug to a large number of participants in different clinical settings to determine its benefits and safety. In Phase III studies, a drug is used as it would be when ready to be marketed. When these studies are completed and the sponsor can demonstrate that the drug is safe and effective under specific conditions, the sponsor applies to the Food and Drug Administration (FDA) for clearance to market the drug to the public.

Phase IV Study Clinical studies for determination of after-effects and secondary results. The study is conducted after the FDA has cleared the drug for marketing. It is initiated by the producer of the drug to gain more information about its safety and benefits.

Common reasons include the lack of a generally accepted therapy or the partial effectiveness of available therapies. Participating in a clinical study might offer the patient a new alternative to "standard" treatment before it will be available to the general public. Many people volunteer for participation in clinical studies because they are survivors of a disease, like cancer, and want to do all they can to prevent cancer in their children. Others want to contribute to research efforts that may help others in the future.

Funding may come from the federal government (via the National Institute of Health), voluntary health agencies such as the National Multiple Sclerosis Society, private industry (via pharmaceutical and biotech companies).

Participants in clinical trials 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

All clinical trials have guidelines about who can participate. Using inclusion/exclusion criteria is an important principle of medical research that helps to produce reliable results. The factors that allow someone to participate in a clinical trial are called "inclusion criteria" and those that disallow someone from participating are called "exclusion criteria". These criteria are based on such factors as age, gender, the type and stage of a disease, previous treatment history, and other medical conditions. Before joining a clinical trial, a participant must qualify for the study. Some research studies seek participants with illnesses or conditions to be studied in the clinical trial, while others need healthy participants. It is important to note that inclusion and exclusion criteria are not used to reject people personally. Instead, the criteria are used to identify appropriate participants and keep them safe. The criteria help ensure that researchers will be able to answer the questions they plan to study.

The clinical trial process depends on the kind of trial being conducted. The clinical trial team includes doctors and nurses as well as social workers and other health care professionals. They check the health of the participant at the beginning of the trial, give specific instructions for participating in the trial, monitor the participant carefully during the trial, and stay in touch after the trial is completed.

Some clinical trials involve more tests and doctor visits than the participant would normally have for an illness or condition. For all types of trials, the participant works with a research team. Clinical trial participation is most successful when the protocol is carefully followed and there is frequent contact with the research staff.

Informed consent is the process of learning the key facts about a clinical trial before deciding whether or not to participate. It is also a continuing process throughout the study to provide information for participants. To help someone decide whether or not to participate, the doctors and nurses involved in the trial explain the details of the study. Then the research team provides an informed consent document that includes details about the study, such as its purpose, duration, required procedures, and key contacts. Risks and potential benefits are explained in the informed consent document. The participant then decides whether or not to sign the document. Informed consent is not a contract, and the participant may withdraw from the trial at any time.

Side effects are any undesired actions or effects of drug or treatment. Negative or adverse effects may include headache, nausea, hair loss, skin irritation, or other physical problems. Experimental treatments must be evaluated for both immediate and long-term side effects.

The ethical and legal codes that govern medical practice also apply to clinical trials. In addition, most clinical research is federally regulated with built in safeguards to protect the participants. The trial follows a carefully controlled protocol, a study plan which details what researchers will do in the study. As a clinical trial progresses, researchers report the results of the trial at scientific meetings, to medical journals, and to various government agencies. Individual participants' names will remain secret and will not be mentioned in these reports.

Every clinical trial must be approved and monitored by a Institutional Review Board (IRB) to make sure the risks are as low as possible and are worth any potential benefits. An IRB is an independent committee of physicians, statisticians, community advocates, and others that ensures that a clinical trial is ethical and the rights of study participants are protected. All institutions that conduct or support biomedical research involving people must, by federal regulation, have an IRB that initially approves and periodically reviews the research.

People should know as much as possible about the clinical trial and feel comfortable asking the members of the health care team questions about it, the care expected while in a trial, and the cost of the trial. The following questions might be helpful for the participant to discuss with the health care team. Some of the answers to these questions are found in the informed consent document.

Yes. Most clinical trials provide short-term treatments related to a designated illness or condition, but do not provide extended or complete primary health care. In addition, by having the health care provider work with the research team, the participant can ensure that other medications or treatments will not conflict with the protocol.

Yes. A participant can leave a clinical trial, at any time. When withdrawing from the trial, the participant should let the research team know about it, and the reasons for leaving the study.