Each phase is designed to answer certain questions. Answering these questions, while giving as few people as possible an unknown treatment, often requires several clinical trials in different “phases”. Each phase is designed to answer certain questions while keeping the people involved as safe as possible. The results of these phases show whether the new drug or treatment is reasonably safe and effective.
Clinical trials are usually conducted in phases that complement each other. Knowing the phase of the clinical trial is important because it can give you an idea of how much is known about the treatment being studied. Participating in each phase of a clinical trial has benefits and risks. Phase I trials usually include 15 to 50 patients who are divided into small groups.
The first cohort receives a dose of the new drug. Doctors may collect blood or urine samples to measure drug levels in patients. 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. Phase I trials are considered early-phase trials and are the first step in testing a new approach in humans. In these studies, researchers evaluate what dose is safe, how a new agent should be given (orally, injected into a vein, or injected into muscle), and how often and what dose is safe.
Researchers closely watch any harmful side effects. Phase I trials usually enroll a small number of patients and are conducted in only a few centers. Patients are divided into small groups, called cohorts. Each cohort is treated with an increase in the dose of the new treatment or technique.
It is determined that the highest dose with an acceptable level of side effects is suitable for further testing. Clinical trials follow a rigorous series ranging from initial small-scale phase 1 studies to large-scale, late-stage phase 3 studies. If a treatment succeeds in one phase, it goes to the next. Phase III clinical trial tests treatment that worked well for volunteers in phase II clinical trial.
This process continues until the developer decides to end clinical trials or submits a marketing request. Drug developers or sponsors must submit an investigational new drug (IND) application to the FDA before starting clinical research. Researchers use this data to refine research questions, develop research methods, and design new Phase 3 research protocols. The process protects volunteers participating in clinical trials from unreasonable and significant risks in clinical trials.
An IRB is an independent committee made up of doctors, statisticians and community members who ensure that clinical trials are ethical and that the rights of participants are protected. If doctors believe the treatment is safe, it will be studied in a phase II trial. During phase 1 studies, researchers usually test a new drug candidate in healthy volunteers (healthy people). Ensuring that all steps are taken helps protect patients and provides accurate results on what the clinical trial is testing.
It is essential that clinical trials include people with a variety of lived experiences and living conditions, as well as characteristics such as race and ethnicity, age, sex and sexual orientation, for all communities to benefit from scientific advances. As in other trials, patients in phase III clinical trials are closely monitored for side effects and treatment is stopped if they are too difficult to manage. Many clinical trials seek to see if people receiving the new treatment live longer than most people without treatment. Sponsors of clinical trials can be individuals, institutions, companies, government agencies, or other organizations that are responsible for initiating, administering, or funding the clinical trial, but who do not conduct research.
Most, but not all, clinical trials in the United States are approved and monitored by an Institutional Review Board (IRB) to ensure that risks are reduced and offset by potential benefits. If enough patients benefit from treatment and side effects are not as severe, phase III clinical trials are started. When you volunteer to participate in clinical research, you help doctors and researchers learn more about the disease and improve people's healthcare in the future. .