Although usually conducted with healthy volunteers, Phase I trials are sometimes conducted with severely or terminally ill patients, for example those with AIDS or cancer. A Phase I trial takes several months to complete. About 70 percent of experimental drugs pass this initial phase of testing.
Phase II studies determine the effectiveness of an experimental drug on a particular disease or condition in approximately to volunteers. This phase may last from several months to two years. A secondary objective for a Phase II trial is to ascertain therapeutic dose level and dosing frequency. Most Phase II studies are randomized, which means that subjects are assigned randomly by chance not by choice to receive either the experimental drug, a standard treatment or a placebo harmless, inactive substance.
Sample 1. Sample 2. Sample 3. Phase 1 Clinical Trial means a human clinical trial of a product in any country, the principal purpose of which is a preliminary determination of safety in healthy individuals or patients, that would satisfy the requirements of 21 C. Phase 2 Clinical Trial means a human clinical trial of a product in any country that would satisfy the requirements of 21 C.
Phase 3 Clinical Trial means a human clinical trial of a product in any country that would satisfy the requirements of 21 C. Phase 4 Clinical Trial means a product support clinical trial of a Product that is commenced after receipt of MAA Approval in the country where such trial is conducted. Phase 4 Clinical Trial may include epidemiological studies, modeling and pharmacoeconomic studies and post-marketing surveillance trials. If a new treatment is found to be safe in phase I clinical trials, a phase II clinical trial is done to see if it works in certain types of cancer.
The benefit the doctors look for depends on the goal of the treatment. It may mean the cancer shrinks or disappears. In some studies, the benefit may be an improved quality of life. Many clinical trials look to see if people getting the new treatment live longer than most people do without the treatment. Larger numbers of patients get the treatment in phase II trials, so less common side effects may be seen. Phase III clinical trials compare the safety and effectiveness of the new treatment against the current standard treatment.
Because doctors do not yet know which treatment is better, study participants are often picked at random called randomized to get either the standard treatment or the new treatment. When possible, neither the doctor nor the patient knows which of the treatments the patient is getting. This type of study is called a double-blind study. Randomization and blinding are discussed in more detail later.
The FDA reviews the results from the clinical trials and other relevant information. Based on the review, the FDA decides whether to approve the treatment for use in patients with the illness the drug was tested on.
If approved, the new treatment often becomes a standard of care, and newer drugs may be tested against it before they can be approved. If the FDA feels that more evidence is needed to show that the new treatment's benefits outweigh its risks, it may ask for more information or even require that more studies be done. We also reference original research from other reputable publishers where appropriate.
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