This page will provide some basic information about clinical trials. For more information about clinical trials in general, please go to

What is a Clinical Trial?

A clinical trial is a research study done in people that follows a strict protocol. The overall goal is to test the effectiveness of a new intervention. There are many types of clinical trials, including tests of new methods of prevention or diagnosis of disease, as well as tests of new methods of treatment. The clinical trials being done by the NF Clinical Trials Consortium are mostly aimed at testing new methods of treatment.

Different Phases of Clinical Trials

Clinical trials are divided into four phases:

Phase I: study of small number of participants intended to determine the safe dose of a drug and side effects.

Phase II: study of safety and effectiveness of a new form of treatment

Phase III: study of effectiveness and side effects of treatment and comparison with other treatments

Phase IV: continued surveillance of safety and effectiveness following release of a drug to market

Most of the trials likely to be done in the NF Consortium are Phase II trials.

Clinical Trial Protocols

A clinical trial must follow a precise protocol which specifies who is eligible to participate, how the treatment is administered, and what kinds of tests need to be done to monitor for side effects. The purpose of a clinical trial is to determine safety and effectiveness of a treatment. Therefore, it is imperative that the rules of the trial be followed exactly. If there are deviations from the protocol, that could result in a failure to determine safety and effectiveness. That is why eligibility criteria are so strict, and why any protocol deviations or unexpected events need to be reported immediately.

Placebo vs. Open-Label Trials

In some cases a clinical trial will be conducted as a placebo-controlled trial. This means that some participants will be treated with the drug being tested, whereas others will be given a preparation that does not have the drug, but looks exactly like the preparation with the drug. For example, the placebo group might get a pill that looks the same as the medication being tested, but does not actually contain medication. Usually, the participants who are treated with drug or placebo are chosen at random, and neither the patient nor the doctor knows which preparation any particular patient is given. Some study personnel do know who is receiving drug and who is receiving placebo and can reveal that if there is an important reason to know, such as the occurrence of a serious side effect. The reason a study might be done in this fashion is to ensure that there is a totally objective way to judge whether the drug works or not. Sometimes a person treated with an experimental medication will feel better just knowing that he is being treated with something. We would not want to mistake that feeling of well being for concluding that the drug is effective. A placebo-controlled trial might also be done if there is some chance that the problem being treated might improve on its own, or at least not get worse, for unknown reasons. We would not want to erroneously conclude that the medication worked in such cases. The progress of a trial is closely monitored by an independent committee, which has the authority to stop the trial if side effects are too severe, if the drug is obviously working (in which case participants on placebo can be given drug), or if there is enough evidence to conclude that the trial is not working.

In contrast to a placebo-controlled trial, an open-label trial involves giving drug to all participants. This tends to be done if there is an objective way to judge whether the drug is working, and there is good reason to believe that the problem being treated will continue to get worse without treatment.

The Informed Consent Process

It is important that anyone who is contemplating participation in a clinical trial have a thorough understanding of the risks and benefits of participation. This is done by having study personnel provide a detailed explanation of what is involved in the trial, what the possible benefits may be, what risks, including side effects, are known to be involved, and what alternatives may be available to participation. After providing this information and answering any questions, participants will be asked to sign an informed consent document indicating willingness to be involved in the trial. A child cannot sign such a document, so studies involving children will require that parents sign, though children old enough to give assent to participate will be asked to sign to that effect. Consent can be withdrawn at any time for any reason, so agreement to participate does not mean that a person is committed to remain with the trial for its full duration. The entire clinical trials process is overseen at each institution by an Institutional Review Board (IRB), which reviews the protocol and consent process, and monitors for progress of the trial and side effects. This is intended to ensure that the rights and interests of participants in clinical trials and other clinical studies are fully respected.

Outcomes of Clinical Trials

Clinical trials can last days, weeks, months, or even years. The number of people who must be studied and the duration of study depends on the nature of the problem for which the treatment is intended. There is a team of scientists and physicians who monitor progress and analyze the information that results from a trial. Ultimately, the results are reported, usually in a publication, to the entire scientific community. The identity of individual participants is kept confidential, however. If the trial shows promising results, it may be followed up by additional studies, and eventually could result in a new form of treatment that is included in routine care.