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Healthy volunteer studies

Before a pharmaceutical company can initiate the evaluation of a new medicinal compound in humans, it must first conduct extensive preclinical or laboratory research. This research typically involves years of experiments including animals and human cells. If this stage of testing is successful, a pharmaceutical company provides these data to regulatory authorities, requesting approval to begin evaluating the drug in humans. This evaluation is done through clinical trials and is conducted in three main phases. Each phase addresses different questions that determine if the drug can proceed to the next phase.

It is an ethical requirement that participants in clinical trials voluntarily decide to take part after having been provided with understandable information about the study. In most studies the participants will be patients with the disease or condition for which the new medicine is being evaluated. In the earliest phase of human trials (Phase I) when only the basic characteristics of the new medicine are being assessed, the volunteers normally do not have the disease or condition, ie they are healthy volunteers.

Phase I studies are primarily concerned with assessing the drug's safety in humans. An attempt is made to establish the dose range tolerated by volunteers for single and for multiple doses. These studies are designed to determine what happens to the drug in the human body - how it is absorbed, metabolised, and excreted. This initial phase of testing in humans is usually conducted in a small number of healthy volunteers (20 to 100), who are reimbursed for their time and discomfort and based on both the study design and the trends/practices for compensation in the local area. Sometimes these studies are conducted in patients (eg, cancer studies) and this may include research into how the disease may impact the way in which the drug is handled in the human body.

An Ethics Committee (EC) or Institutional Review Board (IRB) approval is required to ensure that appropriate safeguards are in place to protect the rights and welfare of research subjects.

This initial phase of testing typically takes several months. About 70 per cent of experimental drugs pass this initial phase of testing.

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