The ICH guidance is basically silent on this subject, although the structure does not specifically prohibit any valid relative link. EMEA has stated that it is not allowed – in “EU Region Question and Answer and Specification Change Request Document”, see question 13:
“In the EU it is possible to refer to a file located in the same sequence or any previous sequence of the same eCTD. It is not possible to refer to other eCTDs.”
If you think about it a little, it requires each agency to maintain a specific set of folders in order for the links to work, and for the sponsor to understand what that structure is.
For example, if the agency stores eCTDs in a known folder path like this:
Gary Gensinger of FDA has said in several presentations that FDA will accept references to documents in other applications.
In order to do this, your publishing tool must be able to handle this scenario. A leaf must exist in your new application (you cannot reference leafs from other applications, only content files). You will need to know:
Access in through the hlink:xref element, and the operation attribute is NEW.
Gary provided the following example:
With the following commentary:
You want to reference a leaf submitted in 0000 of your IND 012345 for NDA282166, sequence 0000 – Your file is named study-report.pdf in 188.8.131.52. Using the following relative path will allow you to reference the study report:
../ gets you out of the 0000 submission in NDA 282166
Adding ../ gets you out of the NDA 282166
Adding IND012345/0000/m5/5352 gets you to your files location
What I haven’t heard is how many people are taking FDA up on this offer.
By the way, the RPS specification will be designed to allow cross application referencing from the start, and will not reply on a relative folder path.