Comparing Legacy, Granular Structures for Clinical Study Reports
As most people who work with eCTD are aware, agencies will accept clinical study reports structured in one of two ways:
- The “Legacy” format where the study report body and appendices, exclusive of datasets and CRFs, are combined into a single PDF. In some cases, the PDF has to be subdivided in order to remain within the ICH file size limit of 100 MB.
- The “Granular” or “E3” format, where the study report, especially the appendices, are submitted as a set of individual files.
There are advantages and disadvantages to each, which are outside the scope of this posting (you can request GlobalSubmit’s white paper “What Makes an eCTD Clinical Study Easily Reviewed by the FDA?” if you are interested in more detail). And in fact, thorough our work with the FDA, GlobalSubmit has found that some clients take a “hybrid” approach and submit a legacy report along with other files. Whatever approach is taken, the study, through the mechanism of the study tagging file, must be constructed so that each component is properly tagged and identified.
In a recent gathering with representatives from a number of Pharma companies, the question was raised (mainly regarding US submissions) as to which of the two formats sponsors were using.
The companies who have been submitting eCTD for some time appear to have made the switch to the granular/E3 format for the most part. However, they had different ways of meeting the review and approval challenges that are brought on when you no longer have a single document (or set of paper binders) to approve:
- One company created an overall approval sheet, stored with the study, that listed the components and gathered approvals for each component
- One company reported assigning ownership to a specific medical writer who was responsible for all aspects of authoring, review and approval
- Some companies still produced a consolidated study report for review purposes or for sending to external parties
- All agreed that it is a significant and time-consuming process to manage the creation and approval of the granular components
Sponsors need to understand how clinical reviewers will be seeing the studies they submit. You can see some FDA presentations on this subject on GlobalSubmit’s Agency Presentations page. Sponsors can also contact us to learn more about the FDA’s eCTD viewer, which is a GlobalSubmit product.