Study Plan, Amendments and Deviations

For a study to be started, there has to be a written study plan, dated and signed by the Study Director. There cannot be much discussion about the definition of the study plan, which is given in the Principles as meaning a document which defines the objectives and experimental design for the conduct of the study . The study plan thus has to delineate the conduct of the whole study in an as detailed way as possible. It is a common truth, however, that 

It is well known, that even with the best intentions of faithful adherence to a pre-conceived plan, there are instances, where a deviation from the written procedure would be a necessary act, based on a rational decision. If such possibilities were not accounted for in GLP, it could be criticised with good reason that GLP were an inflexible, bureaucratic impediment to truly scientific investigations. It depends, however, on the exact circumstances how such changes are to be treated in a GLP compliant way. The definitions in the OECD Principles distinguish two different cases, namely the Amendment and the Deviation. 

There are, however, a number of other problems which lie not only with the interpretation of the expressions intended and unintended , but also with the concrete application of the tools amendment and deviation in some special situations. 

These are the more or less straightforward cases, but there can be more contentious ones. In a field study, the exact date of the application of the test item can in most cases not be predicted with sufficient accuracy, since the time point of application depends on a good number of variables that cannot be influenced by the Study Director or the Principal Investigator, such as weather conditions and growth stage of the crop to be treated. It is therefore customary for field studies not to specify an exact date for the spraying of the crop, but to 

Other possibilities of more or less unintended changes to the study plan may occur, when additional interventions may become necessary, such as pesticide treatments of crops in field studies to combat some disease that is not the target of the study, or veterinary interventions in toxicity tests to treat some lacerations in a dog. 

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