Before these new treatment options can be brought to market, made available to the general patient population, and prescribed on a routine basis, they must be approved by the regulatory authorities. This is where clinical trials come in.
What is known about the safety and efficacy of investigational drugs?
The effectiveness and safety of an investigational drug has not yet been shown. The development of a drug goes through several phases. The investigational drug in this trial has already been studied in Phase I and Phase II studies. The investigational drug is being studied further in this Phase III trial in a larger number of patients. Phase III is the phase of clinical development that can lead to approval of a drug. However, there is no guarantee that this drug will become commercially available. About 1,000 patients will be allowed to participate in this trial, which began recruiting participants in November 2010.
If you want to know more details about the phases of clinical trials please read in the Phases of clinical trials section.
A careful and systematic approach to approval
Clinical trials are research studies. They offer a structured way to carefully study a new, or investigational, drug. Investigational drugs are those that are not yet approved by the respective regulatory authorities and thus are not yet available on the market. Through clinical trials, a limited number of patients are able to access investigational treatments, under the careful supervision of physicians involved in the trial.
During clinical trials, medical researchers evaluate the safety and efficacy of a new drug (or for that matter, a new treatment approach or new diagnostic technique). The drug is often compared to the current best practice – the so-called “standard of care” – which may be another drug or a non-drug treatment approach. If no treatment has proven to be effective, a placebo may be used for comparison. Clinical trials may also compare two or more approved treatments to evaluate which one is more effective.
Clinical trials typically look at the effect of different therapies or drugs in groups of patients with the same disease. Commonly, the goal is to identify which treatment provides benefits such as improvements in health or fewer side effects.
The steps of clinical research
Clinical trials are conducted in four phases (I-IV) as described below. Each phase corresponds to one or more separate trials.
In addition to the phases of development, there are many different types of clinical trials. They vary in terms of their purpose or the way they are organized. You can find more information about this in the Types of clinical trials section.
The decision-making process
Participation in clinical trials is entirely voluntary. In order to make a well-informed decision, you need to learn about the risks and benefits of participating in the clinical trial. The process of “informed consent” helps to achieve this. Informed consent involves health care professionals explaining key details of the trial, such as the goal of the study, the procedures to be used, and potential risks and benefits, to patients interested in the trial. For further information, please see the Informed consent section.
Inclusion and exclusion criteria
Every clinical trial has specific inclusion/exclusion criteria, developed by the researchers, that determine a patient’s eligibility for the trial. These criteria outline who can and cannot participate in the trial. An example of inclusion criteria is that only patients of a certain age or with a particular severity of disease may participate. An example of exclusion criteria is that patients who are taking certain medications or are currently hospitalized cannot participate in the trial. By applying specific inclusion and exclusion criteria, a unified patient population is created; such groups of patients that share some key defining characteristics are called cohorts. Defining the target patient population in this manner also allows more accurate interpretation of the study results. To learn more about inclusion/exclusion criteria, please see the How to participate section.
If you are interested in participating in a clinical trial, please talk to your doctor. Before you talk to your physician, it may be helpful to look at the information sheet called “Questions to ask your doctor” (PDF), which will help you ask specific questions about participating in a trial.
Written by medical writers Claudia Sarkady and Darlene Grzegorski
Last updated: 25 July 2011
Sources: 1. www.clinicaltrials.gov, 2. www.who.int, 3. Fundamentals of Clinical Trials, Lawrence M. Friedman, Curt D. Furberg, David L. Demets, 4th edition, Springer, 2010, 4. Oncology Clinical Trials, Wm. Kevin Kelly, Susan Halabi, Demos Medical Publishing 2010