In clinical trials, phases are meant for researchers to conduct experiments with a health intervention. The aim is to find sufficient evidence for a process that might be useful as a medical treatment. For instance, if a pharmaceutical study is being conducted, the phases will start with drug design and discovery. The next step involves animal testing and if that is successful, they start the clinical phase of development. They test the safety of the drug in humans and expand the test for determining if the treatment is effective.
There are mainly four phases in a clinical trial that involves drugs. The drug development process normally proceeds through all four phases and continues for years. Once the drug being studied passes through phase 1, 2 and 3 successfully, it gets approved by the national regulatory authority for general use.
Phase 1 is designed for determining maximum amount of drug that can be given to a human before adverse effects become dangerous or intolerable. This phase is also referred to as ‘First-in-man Studies’. A group of 2-100 healthy volunteers participate in this phase. They are observed by the researchers in a clinical trial clinic.
In Phase 2 clinical trial, researchers evaluate whether the drug has any biological effect or activity in the human body. This is done once the dose or range of doses of the drug is determined from Phase 1. Larger group of volunteers participate in this second phase. This phase also continues the safety assessments of Phase 1. Some phase 2 trials are designed as case series. They demonstrate the activity and safety of the drug in selected patients.
Even BA/BE studies are important in clinical trials under which the test product is compared with the product already being sold in the market.
