The different phases of a clinical trial

What are the different stages of a clinical trial? Trials to test new drugs are usually completed in 4 phases. When success is achieved in the first phase, it will pass to the phase II, III and then phase IV which consists of a study conducted following approval by regulatory bodies.

Image credit

Pre-clinical phases of a drug or device involves testing on non-human cells that provide information about how effective it is, any toxicity problems and how this impacts the drug organism or the device itself. For more information on Adaptive Phase 1 Studies, visit a site like https://www.richmondpharmacology.com/specialist-services/adaptive-phase-i-studies

Phase I involves the testing of drugs on healthy human volunteers in a clinical trial, with small doses at first and subsequently increased doses further on but still lower than the therapeutic dose. This stage used to be called ‘first-in-man’ but was replaced by the ‘first-in-human’ for better gender neutrality. This phase is to examine how much of the drug can be given to a person before the side effects become apparent.

image credit

A small group of healthy volunteers will be invited to the clinic for clinical trials, so that they can be observed around the clock.

Phase II consists of testing of a new device or drug on patients for whom there would be a clinical benefit to examine potential side effects and how effective it is.  At this stage, patients receive a safe ‘therapeutic dose’. After Phase I has established a dose level, that phase to determine whether the drug has a real effect and how well it works. Some of the tests will involve Phase I and II combined for toxicity and efficacy.