When a new medication is under development, it must go through lengthy testing to ensure it is both safe and effective. Testing begins in vitro and must proceed through a number of animal trials before the drugs can be tested in humans. When new drugs are tested in humans, these tests are called pharmaceutical clinical trials. This means the drugs are being tested in people who have the medical conditions the drugs have been developed to treat.
Pharmaceutical clinical trials run through several phases, and each is important in gathering information about the overall efficacy of the drug which is being tested. Throughout all phases, trials must be conducted ethically, and in a way that reduces variation among trial participants. This is important because too much variation can make it difficult to make accurate conclusions about clinical data obtained during a trial. For this reason, patients who wish to enroll in a clinical trial may be screened on the basis of previous treatments, age, symptoms, and other factors.
Phase I trials usually include a small number of healthy patients. During this phase, the drug is tested for acute toxicity. Dosage testing may also begin in this phase. In Phase II trials, the drug is tested in patients on a preliminary basis, to determine the most effective dose which can be administered. Safety and efficacy testing may also be initiated here.
In the final step of the process, large numbers of people are enrolled in a Phase III trial. In Phase III pharmaceutical clinical trials, the safety and effectiveness of the drug is tested on a large scale, often in several different locations. The health benefits of the drug, as well as any side effects, are noted during this phase. In addition, the drug is compared to standard treatments for the condition, to determine whether it is more effective than currently available treatments.
All three phases of pharmaceutical clinical trials provide important information about a newly-developed drug, but it is the third phase which may determine whether a drug can be marketed to the public. In the United States, for example, any new medication must be proven to be at least as effective as all other current treatments before it can receive approval from the FDA. In Europe, a regulatory body called the European Medicines Agency evaluates new drugs developed in countries of the European Union.