Analysis Populations Used for Safety Data

It is ultimately the sponsor s responsibility to ensure that cGCP is followed in its clinical trials, even though some of the work is contracted out to CROs and other service providers. With regard to analytical laboratories, GCP guidances require that all laboratories have full documentation, data-audit trails, standard procedures, trained staff, archives of samples and data, and routine quality assurance inspections (Prokscha, 2007). If multiple laboratories were to be used, the sponsor would need assurance that GCP requirements were met for every one. In contrast, if a central laboratory is used and all samples are shipped to it, the sponsor only needs to check GCP compliance at that laboratory. 

It should be noted that using central laboratories can be considerably more expensive than would be the case if samples were sent to local laboratories close to each investigational site. The central laboratory used can be many miles from some of the investigational sites, even in another country or continent. Expedited shipping under very carefully controlled conditions is necessary to ensure that the samples arrive at the central laboratory quickly and safely. However, obtaining optimum quality laboratory data is critical, and the necessary expenditure involved here is well worthwhile. 

Various analysis populations for clinical trial data can be defined and used in statistical analyses. Of relevance in this chapter are the intent-to-treat (ITT) 

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