The safety of clinical trials is an important part of studies; each drug must establish an acceptable evidence base for safety and efficacy and complete each stage of pre-marketing clinical trials until regulatory authorities are satisfied. There is a strict definition of these clinical trials that investigate:
Pharmacological effects and / or other pharma dynamic effects, Potential side effects, Drug absorption, distribution, metabolism and excretion rate.
General Safety And / Or Effectiveness
The exact nature of a pre-registered clinical trial depends on a number of factors, including the nature of the drug itself. It also depends on the disease or clinical indication that is ultimately expected to be treated. The nature of the relevant patient group is also an important factor. There are four separate testing phases, but there is usually some overlap between them from a real life perspective. Phase trials are usually conducted in volunteers who are healthy people and are referred to as “subjects” in the literature and official documents. All subsequent test phases include volunteers diagnosed with a disease for which the drug is a planned treatment. As a result, these individuals are sometimes referred to as “patients” or “voluntary patients”. Here, we will provide some brief information about some important concepts that characterize the Phase I, II, III, and IV trials, and why they sometimes overlap.
Phase 1 Clinical Studies
The first of a series of studies is the first study of the response of healthy human volunteers instead of animal models. The objective at this stage is to establish a drug safety profile and identify potential beneficial or adverse effects. Research focuses on the absorption and distribution pathways in the body and how drugs are removed. Maximum tolerance is also established. Possible doses and prescriptions (schedule and frequency) can also be examined considering the next step in the testing process. The main purpose here is the safety of the drug rather than considering its effectiveness. A typical time scale is about 12 months and probably involves 100 subjects. Serious adverse events are relatively rare at this stage, and every effort is made to minimize the potential risk to the subject. For some drugs (eg, certain drugs used to treat cancer), the known toxicity of that drug means that research in healthy volunteers is simply not ethically feasible It is important to be careful.
Phase II Study
The purpose of this step is to study the drug when administered to a patient who has already been diagnosed with the exact disease, and the product is expected to provide treatment. Goals include establishing optimal doses / dose regimens and maximizing benefits with minimal tolerable side effects. Phase II trials can also continue to investigate excretion and metabolic rates to establish important efficacy and safety indicators for subsequent studies. The number of participants is usually much higher than in phase 1 clinical studies, and perhaps hundreds of patients are recruited. Studies can last for weeks or months, and typical studies are double-blind in design.