Clinical trials are systematic studies conducted in human subjects to determine the safety and efficacy of a new drug. The purpose of clinical trials is to find out the safer, more effective drugs or methods or therapies to screen, prevent, diagnose or treat a variety of diseases. These studies follow strict scientific standards, thus protect the patients and help to produce reliable study results. Clinical trials are composed of various steps mainly categorized into 4 phases; each phase is designed to find out specific information and each new phase of a clinical trial builds on information from previous stages. Clinical trials must apply the pharmacological principles/ techniques in order to study the mechanism of action of drugs in humans. This is simply known as clinical pharmacology.
Clinical pharmacology is defined as the science that deals with the actions and metabolism of drugs in living animals. Clinical pharmacology has a responsibility to develop and establish the safe and effective drug therapies. In clinical research, Clinical Pharmacology is used as translational science in which basic information about the relationship between dose, exposure and response (efficacy or safety) is applied in the context of patient care. The major contribution of Clinical Pharmacology include: Knowledge of E-R (Exposure- Response) relationship that helps to select a suitable dose/ dosing regimen and identify optimal drug products, and how it is altered by intrinsic (age, gender, renal function etc.) and extrinsic (diet, drugs, life-style) factors of an individual patient. The clinical pharmacology is based on the pharmaco-kinetic (PK) and pharmaco-dynamic (PD) studies and their relationships (PK/PD) in healthy subjects as well as in patients. The pharmaco-kinetic studies mainly aim at the kinetic (ADME) properties of the drug where as the pharmaco-dynamic studies focuses on the pharmacological and therapeutic action of the drug. PK studies are simply what the body does to the drug which gives exposure and PD studies are what the drug does to the body that gives the response. The drug actions can be altered by modifying its pharmaco-kinetic and pharmaco-dynamic profiles. In phase I and in phase II clinical trials, these studies are carried out to establish the safety and efficacy of a drug which will be followed by the phase III trials in which the therapeutic effect of drug will be established by comparing with the already established drug (standard).
First two phases of clinical trials are monitored by the clinical pharmacologists. The function of clinical pharmacologists is to study how the drug works, how it interacts with the biological systems as well as with the other chemicals/ drugs and it’s out comes that may consists safe and adverse effects. By these studies the clinical pharmacologists can be able to understand the basic action of drugs in human beings.
Clinical trials require strong contribution of clinical pharmacologists to predict the dose, safety and efficacy of a new drug. The need and the applications of clinical pharmacology in clinical trials are growing rapidly and providing great opportunities to clinical pharmacologists.
Gouthami Bommapala, M.Pharm
JLI Student – Advanced PG Diploma in Clinical Research & Pharmacovigilance