Common Questions

What is a clinical trial?

A clinical trial is a scientific experiment that is done with people who volunteer to participate. Like any scientific experiment, the conditions of a clinical trial are carefully controlled and closely monitored. For example, study volunteers must fulfill enrollment criteria in order to be eligible for participation. The criteria are determined with consideration to the validity of the research results and the safety of the volunteers.

In general, the purpose of clinical trials is to evaluate the safety, effectiveness or best dosage schedule of experimental drugs or medical devices in persons having a specific disease or health condition. New drugs have to be evaluated before they are given to the general population. The safest and most effective way to evaluate drugs is in the format of a clinical trial.

What is this I’ve heard about research volunteers being blinded and taking placebos?

Often a clinical trial is designed so that neither the study volunteer nor the medical staff knows if the study volunteer is actually receiving the experimental drug. This would be called a “blinded study.” A study is blinded in order to eliminate the possibility of unfairness in the assessment of the effectiveness of the study drug.

In a blinded study, the study volunteers are randomized, that is they are randomly assigned to receive the study drug or something that looks like the study drug. This might be a standard drug that has been reformulated to look like the study drug, or it might be a placebo. A placebo looks like a drug but actually does not contain any active substance.

How can I be sure that I am assigned to the study drug that I want?

Well, you actually can’t. The study group you are assigned to is decided randomly, like flipping a coin or drawing a card. Often, a computer program randomizes patients. The study doctor has no influence as to which study group you are assigned within a given clinical trial.


Would I be the first person ever to take the experimental drug?

In order for a drug to be approved by the Food and Drug Administration, it must go through different phases of drug development. You can find out what phase your clinical trial is in by asking the study doctor or any member of the clinical trial staff. There are either Phase I, II, III, or IV clinical trials.

A Phase I trial involves giving the experimental treatment to healthy people in order to generate preliminary information on safety.

A Phase II trial is usually the second stage in testing a new drug in human beings. Generally, the phase II study is carried out on people having the disease or condition for which the experimental treatment has been developed. The main purpose is to provide preliminary information on effectiveness of the drug and to provide additional information on safety and side effects. Generally only a small number of participants are recruited for Phase 11.

Usually the Phase III trial is the third and final stage in testing a new drug in people. Ususally a large number of people are recruited from many countries.The Phase III trial is concerned with assessment of dosage effects, effectiveness, and safety and aimed at providing information for labeling in relation to use by the general public. Once this phase is completed the drug manufacturer may request permission to market the drug for the disease or condition for which it has been tested.

A Phase IV trial is performed after the drug has been FDA approved for and is typically done under circumstances approximating real world conditions instead of carefully controlled conditions. Often it measures the long-term effects of a new drug.


Does anyone monitor clinical trials?

In New Zealand all clinical trials are conducted following approval from the Ethics Committee and the SCOTT Committee

The study doctor is directly responsible for your safety. He or she will be watching for any abnormalities in test results.


Why would someone want to join a clinical trial?

Each clinical trial is different, therefore the benefits vary. Some clinical trials offer volunteers the opportunity to try treatments that appear to be promising but are not available yet to the general public. Often clinical trials have rigorous health monitoring and this may be an opportunity to have their general health assessed.


What should I be aware of as I consider joining a clinical trial?

Before you enroll in a study you will be given a consent form to read and sign. This form gives you all the information about the clinical trial you are considering. Be sure that you have read the consent form thoroughly. Some people read it two or three times. If something is not clear on the consent form, or you want additional information, be sure to ask all of your questions to the study doctor or the study coordinator, whoever reviews the consent form with you. Every clinical trial is different, and the benefits and risks of participating vary. The consent form is your best source of information.


What if I read something on the consent form that I don’t like?

Although previously you might have talked to the study doctor or study nurse, you might read the consent form and find out something about the clinical trial that you didn’t expect. Perhaps it never occurred to you to ask about the risks of a certain procedure, or a placebo period. Maybe you didn’t know that there would be an overnight study visit, and maybe any one of these details is enough for you to decide that you don’t want to join after all. To sign the consent form is your decision and it is important that you feel fully informed and satisfied with all aspects of the consent form before signing.


Will it cost me anything to participate? Will I be paid?

In general, there is no cost to volunteers or their insurance agencies for any research related costs.  Travel costs are usually met by the research centre.



Meinert, Curtis L. Clinical Trials Dictionary: Terminology and Usage Recommendations. The Johns Hopkins University; School of Hygiene and Public Health; Center for Clinical Trials, © 1996.