In this article, we will look at the 4 phases of clinical trials and what is studied during each one.
What are the 4 phases of clinical trials?
- Phase 1 Clinical Trials: Phase 1 involves evaluating the drug’s safety, identifying any side effects, and determining the best way to administer it. Usually, 50 to 100 healthy volunteers make up this phase.
- Phase 2 Clinical Trials: This next stage typically involves 100 to 300 patients who have the condition for which the drug, device, product, or treatment has been developed. Researchers evaluate the medication’s short-term safety and efficacy, identify the dosage that produces the fewest side effects, and perform a small-scale placebo comparison.
- Phase 3 Clinical Trials: The number of volunteers must increase for phase 3. Typically, between a few hundred and a few thousand patients participate so that scientists can verify the medication’s security and efficacy and contrast the new medication with other substances (e.g., a placebo or other therapies).
- Phase 4 Clinical Trials: After the drug has been approved, researchers will study its efficiency in a wide range of patients, keep track of its safety in a sizable population, and enable the creation of new applications for the substance. These studies, which frequently involve thousands of patients, can guide future investigation and advancement.
Phase 1 Trials
Check the safety of a novel treatment on humans. Doctors determine the most effective method of treatment.
A Phase I trial’s objectives are to:
- Determine the safety of a novel treatment.
- Choose the most effective delivery method for the new therapy, such as a vein or the mouth.
- Check for indications that the new treatment is having an effect on the cancer.
In phase I trials, 15 to 50 patients are typically divided into smaller groups. Cohorts are the name for these groups. The new medication is administered to the first cohort. To assess the patient’s’ drug levels, doctors may take blood or urine samples.
A new cohort is given a higher dose of the same medication if the initial cohort does not experience any serious side effects. With each new cohort, the dose is raised until the medical professionals determine the optimal dose. Every patient is tested to see how they are responding to the treatment after each dose increase. The treatment will proceed to be examined in a Phase II trial if the medical professionals determine that it is safe.
Phase 2 Trials
Check to see if a new treatment works in one type of cancer.
A Phase II trial typically enrolls less than 100 patients. Despite the fact that the primary goal is to determine whether the treatment is effective, doctors continue to closely monitor patients’ side effects. If the new treatment proves effective, it may be studied further in a Phase III trial.
Phase 3 Trials
Check to see if a novel treatment is more effective than the norm.
Hundreds to thousands of patients may participate in phase III trials across the nation or the globe. Each participant in a Phase III clinical trial has an opportunity to be in one of the following categories:
Control group: the individuals who receive standard care.
Study group: the individuals who receive the experimental new medication.
Doctors think the new treatment is as good as the current one and may even be better, but they are unsure if it is.
The FDA examines the clinical trial results following the Phase III trial to ensure that the medication is suitable for human use and is both safe and effective. In order for the treatment to be accessible to all patients, the FDA must decide whether to approve it.
Phase III trials are the subject of numerous frequently asked questions. These consist of:
How are the groups of patients formed?
Which patients are in the control group and which patients are in the study group is decided by a computer. Each group has a chance of including a patient. The doctor makes the choice, not the patient. It is random and solely the result of chance. By doing this, bias in the clinical trial is reduced. (Bias occurs when a study’s findings are impacted by human decisions.)
Does my doctor know which category I fall under?
In single-blind studies, only the doctor is aware of the patient’s assignment to the control or study group. In studies that use double blinding, neither the participants nor the researchers are aware of who belongs to which group. (Doctors can find this information in the study file in the event of an emergency.)
Was a placebo given to me?
A placebo is a substance that appears to be medication but is not. If a placebo is used, it is administered along with the best recommended course of treatment. This enables medical professionals to contrast standard care alone with standard care combined with a new drug. The placebo may be administered alone in the absence of a standard treatment, but this is uncommon in cancer trials.
Phase 4 Trials
Find out more details regarding long-term side effects.
Testing on people that takes place after the Food and Drug Administration (FDA) has already given a drug (or other treatment) approval and it has begun to be marketed for sale. Phase 4 trials are carried out to evaluate the long-term safety and efficacy of a treatment and to spot any side effects that may not have been noticeable in earlier trials. Numerous participants typically participate in phase 4 trials.