Volunteers benefits/limitations

There is a large amount of conceptual similarity in the approach to Phase I trial design, regardless of the therapeutic area however, there are some important differences. One major consideration is the selection of the population of humans for the Phase I study. For most therapeutic indications, healthy volunteers are the participants. They are compensated for the inconveniences of participating in the study, but they are not in a position to receive medical benefit. The use of healthy volunteers substantially limits the ability to observe the desired therapeutic goal. For example, if an agent is intended to correct metabolic deficiencies, or lower elevated blood pressure, there may be no detectable changes in healthy participants. 

Human experimentation is limited by statute and by ethical considerations to studies in which there is no prospect of permanent harm to the volunteers participating in the study. This obviously limits the scope of the results obtained by this route, although it can be employed to detenrane the onset of early symptoms or to determine threshold levels for detection of odors or irritation as a potential warning mechanism. Any experiment of this type must be carefully reviewed by a human subject review committee of the institution or corporate research facility where the research is being contemplated. Any subject of such experimentation must be fuUy informed of any risks or benefits and normally must be given an opportunity to withdraw at any point. However, even with this restriction, many experiments using volunteers have been conducted and significant data have been obtained on symptoms initiated by modest levels of... 

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