Medicines for Special Populations

Definition of Clinical Trials

A ‘medicinal clinical trial’ is any investigation of one or more medicines in humans, intended to:

  • Discover or confirm the clinical, pharmacological and/or other pharmacodynamic effects – i.e. what the medicine does to the body.
  • Identify any adverse reactions
  • Study absorption, distribution, metabolism and excretion (ADME ) – i.e. to find out how the medicine enters the body, how it is distributed, broken down and how it then leaves the body.
  • Compare different medicines to find the most effective one – or to find sub-groups of patients who benefit the most

The objective of such trials is to confirm the medicine’s safety (how well it is tolerated) and/or efficacy (how well it works). (Adapted from Directive 2001/20/EC of the European Parliament and of the Council).

Clinical Trials: Scientific Approach in Design and Analysis

Clinical trials should be designed, conducted and analysed according to sound scientific principles to achieve their objectives. They should also be reported appropriately. Rational medicines development must ask important questions and answer them with appropriate studies. The main objectives of any study should be clear and stated in detail.

Important considerations include:

Selection of Clinical Trial Participants: Special Populations

A number of special circumstances and populations require consideration on their own when they are part of the development plan. The stage of development and the indication (disease or condition) to be studied should be also taken into account in selecting the population (e.g. normal healthy individuals, patients, or special populations in early phase development), as well as previous non-clinical and clinical knowledge.

The variability of groups of patients or healthy volunteers studied in early trials may be limited to a narrow range by strict selection criteria. As medicines development proceeds, the populations tested should be broadened to reflect the target population.