Phases of clinical trials explained in detail.
Phase I trials test whether a new treatment is safe and look for the best way to administer it. Phase II trials evaluate whether a type of cancer responds to the new treatment, phase III trials evaluate whether a new treatment is better than a standard treatment. While preclinical research answers basic questions about the safety of a drug, it is not a substitute for studies on the ways in which the drug interacts with the human body. As the developers design the clinical trial, they will consider what they want to achieve for each of the different phases of clinical research and begin the process of researching new drugs (IND), a process they must go through before clinical research begins.
Clinical Research Phase Studies Investigational New Drug Process clinical trials follow a typical series from initial, small-scale phase 1 studies to large-scale, late-stage phase 3 studies. Phase 1 studies are closely monitored and collect information about how a drug interacts with the human body. Researchers adjust dosing schedules based on animal data to find out how much drug the body can tolerate and what its acute side effects are. As the phase 1 trial continues, researchers answer research questions related to how it works in the body, the side effects associated with increasing the dose, and early information on the effectiveness of drug administration in limiting risks and maximizing potential benefits.
This is important for the design of phase 2 studies. Phase 3 studies provide most safety data. In previous studies, less common side effects may not have been detected. Because these studies are longer and longer lasting, results are more likely to show rare or long-term side effects.
In the United States, each research study is reviewed by an Institutional Review Board (IRB). An IRB is a committee of medical experts, scientists, physicians and other representatives who carefully consider each new study before starting. All clinical trials should be approved based on a careful evaluation of potential benefits and risks. This helps protect patients' health and rights.
If a new treatment is determined 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 doctors seek depends on the purpose of treatment. It may mean that the cancer shrinks or disappears. Or it could mean that there is a long period of time when the cancer does not grow, or that there is a longer time before the cancer returns.
In some studies, the benefit may be an improvement in quality of life. Many clinical trials seek to see if people receiving the new treatment live longer than most people without treatment. Before researchers are allowed to test their treatments on humans, they conduct laboratory research, and these results must be evaluated and then approved by the FDA. The FDA is the agency responsible for protecting public health by ensuring the safety, effectiveness and protection of drugs, biological products and medical devices.
This is the first phase of human testing and is designed to assess the safety of treatment. Researchers test the new treatment on a small group of volunteers, usually between 20 and 80 people. Sometimes, these tests are done on healthy people rather than on people who would actually be using the treatment for its intended purpose. This phase is where some possible side effects of treatment are identified.
About 70% of research entering Phase I successfully completes this phase. The third phase of clinical research is to determine whether this new treatment is better or comparable to the treatment already available or “standard”. If the new treatment is not at least as good or even better than the standard treatment, then there is little or no value in bringing the new treatment to the public. This means comparing treatment outcome, cost and side effects.
To answer these questions, phase III clinical trials are large, usually involving several hundred to several thousand participants, and the study can last several years. If a new treatment successfully completes Phase III, the study sponsor may seek FDA approval to market the treatment. This last phase of clinical research monitors safety and effectiveness over a long period of time. Some treatments that work well under research conditions may not work as well under real-life circumstances, and some side effects may become apparent only over time.
Of course, you can sometimes find that certain treatments improve over time, and it's important to know that too. Depending on the results of Phase IV, labeling and declarations can be modified. The nih Trials and You website is a resource for people who want to learn more about clinical trials. Innovative scientific advances in the present and in the past were only possible thanks to the participation of volunteers, both healthy and sick, in clinical research.
Answering these questions, while giving as few people as possible an unknown treatment, often requires several clinical trials in different “phases”. The goal of clinical research is to develop knowledge that improves human health or increases understanding of human biology. The way to find out if a new drug is safe or effective is to test it in patients in clinical trials. The potential new treatment goes through a series of steps or phases of clinical trials to gain more knowledge about the safety and effectiveness of the therapy.
After completing a clinical trial, researchers carefully examine the information collected during the study before making decisions about the meaning of the findings and the need for further testing. The concept of a clinical trial begins with scientific research in a laboratory, where a possible new treatment is tested in cell and animal models. All new treatments must undergo clinical trials before being approved by the Food and Drug Administration (FDA). Clinical trials are an important part of finding cures and promoting the long-term health and quality of life of children with cancer.
Unlike other phases of clinical trials, there is almost no chance that people participating in phase 0 trials will benefit. Doctors use clinical trials to find out if a new drug, treatment or combination works and if it is safe for people. Before submitting a marketing application, the developer must have adequate data from two large, controlled clinical trials. After completing phase 3 clinical trials, the health of patients who received the different types of treatment is compared to the control groups.
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