What is a clinical trial?
A clinical trial is a research study to answer specific questions about vaccines or new therapies or new ways of using known treatments. Clinical trials (also called medical research and research studies) are used to determine whether new drugs or treatments are both safe and effective. Carefully conducted clinical trials are the fastest and safest way to find treatments that work in people. Trials are in four phases: Phase I tests a new drug or treatment in a small group; Phase II expands the study to a larger group of people; Phase III expands the study to an even larger group of people; and Phase IV takes place after the drug or treatment has been licensed and marketed.
What is a placebo?
A placebo is an inactive substance in the form of pill, liquid, powder or some other form, It looks like the active drug but has no treatment value. In clinical trials, experimental treatments are often compared with placebos to assess the treatment's effectiveness. In some studies, the participants in the control group will receive a placebo instead of an active drug or treatment.
What is a placebo controlled study?
A method of investigation of drugs in which an inactive substance (the placebo) is given to one group of participants, while the drug being tested is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective in treating the condition.
What is a placebo effect?
A physical or emotional change, occurring after a substance is taken or administered, that is not the result of any special property of the substance. The change may be beneficial, reflecting the expectations of the participant and, often, the expectations of the person giving the substance.
Can a participant leave a clinical trial after it has begun?
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. You should also explain the reasons for leaving the study, but you are not obliged to do so.
What are side effects and adverse reactions?
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.
What is informed consent?
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. If the participant's native language is not English, translation assistance can be provided. 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.
What is a protocol?
A protocol is a study plan on which all clinical trials are based. The plan is carefully designed to safeguard the health of the participants as well as answer specific research questions. A protocol describes what types of people may participate in the trial; the schedule of tests, procedures, medications, and dosages; and the length of the study. While in a clinical trial, participants following a protocol are seen regularly by the research staff to monitor their health and to determine the safety and effectiveness of their treatment.
What is a control or control group?
A control is the standard by which experimental observations are evaluated. In many clinical trials, one group of patients will be given an experimental drug or treatment, while the control group is given either a standard treatment for the illness or a placebo.
Who's eligible to participate in a clinical trial?
Each study has its own guidelines for who can participate. Generally, participants are alike in key ways - such as the type and stage of cancer, age, gender, and other factors.
What is a randomization?
A method based on chance by which study participants are assigned to a treatment group. Randomization minimizes the differences among groups by equally distributing people with particular characteristics among all the trial arms. The researchers do not know which treatment is better.
What is a recruiting period?
This is the period during which a trial is attempting to identify and enroll participants. Recruitment activities can include advertising and other ways of soliciting interest from possible participants.
What is risk-benefit ratio?
The risk –benefit ratio is an explanation of the risk to individual participants versus the potential benefits if participating in the clinical trial. The risk/benefit ratio may differ depending on the condition being treated and the health status of the participant.
What is a double-blind study?
A clinical trial design in which neither the participating individuals nor the study staff knows which participants are receiving the experimental drug and which are receiving a placebo (or another therapy). Double-blind trials are thought to produce objective results, since the expectations of the doctor and the participant about the experimental drug do not affect the outcome.
What is efficacy of a drug or treatment?
The maximum ability of a drug or treatment to produce a result regardless of dosage. A drug passes efficacy trials if it is effective at the dose tested and against the illness for which it is prescribed.
What are inclusion/exclusion criteria?
The medical or social standards determining whether a person may or may not be allowed to enter a clinical trial. These criteria are based on such factors as age, gender, the type and stage of a disease, previous treatment history, and other medical conditions. It is important to note that inclusion and exclusion criteria are not used to reject people personally, but rather to identify appropriate participants and keep them safe.
What is an institutional review board/ independent ethics committee?
An institutional review board (IRB), also known as an independent ethics committee (IEC) or ethical review board (ERB) is a committee of physicians, statisticians, researchers, community advocates, and others that ensures that a clinical trial is ethical and that the rights of study participants are protected. An IRB/IEC should safeguard the rights, safety, and well-being of all trial subjects. Central Ethics Committee for clinical trials of medicaments and medicinal products (CEC) is responsible for the review of proposed clinical trials in the Republic of Croatia.
What is a pharmacokinetics?
In the human body, that refers to the processes of absorption, distribution, metabolism, and excretion of drugs.
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