Recently, more and more, I’m being asked my opinion about the scope of SEND and if a certain study or even a certain endpoint should be provided in SEND. Clearly, I’m referring to data which do not have an obvious example in the SEND IG. However, the lack of example cannot be the defining criteria as it would be impossible to include an example of every possible endpoint. So, the answer becomes more subjective and relies on experience and good judgement and for that reason, I find these very interesting questions. I love the discussion that they provoke.

Often, there is an unusual endpoint that was not considered when the existing domain was designed, however it’s clear that the data easily fit. We still just have a test, a result value and it’s timing. To me, that becomes an easy answer to say “yes, such data should be represented in SEND”.

Then there’s times where a type of data almost fit. Maybe there’s an additional property of the data that doesn’t have a natural variable. We could ignore it or put it in a supplemental qualifier. There may even be an appropriate SDTM variable that already exists which we could add into our SEND domain. Then there’s times when there’s important data that just don’t fit in any of the existing domains. We could represent those data in a custom domain. Should we?

The Scope of SEND section in the FDA’s Technical Conformance Guide is our best reference point for such questions and I often summarize this as “if the data are important for determining the safety assessment, and the data can be represented in SEND, then they should be in SEND”. However, it’s the subjective nature of asking, “if the data can be represented in SEND,” that may be troublesome. Does that really mean going as far as creating a custom domain?

Not all organizations have the knowledge or tools to get as creative as including additional variables or using custom domains. In addition, consideration should be given to the FDA and if their tools would be able to consume and present the data for analysis. Simply being able to place the data somewhere in SEND doesn’t mean that their tools will be able to do anything useful with the data.

So, can a certain study or data type be represented in SEND? Most of the time they probably can, though maybe not easily, and how useful would it be? The more ‘creative’ we need to get to place data in SEND, then potentially the less useful it is.

This is the conversation I seem to be having more and more. I’d love to hear some feedback from the agency regarding things like custom domains. Do they have tools that could be used to analyze the data such a domain? Would they expect to receive custom domains? Would they be useful in determining the safety of the compound? I’d really like to know.

To let me know your opinion on the matter, email me at

‘til next time


Published by Marc Ellison

Self-confessed SEND nerd who loves geek-ing out about everything to do with SEND. Active CDISC volunteer and member of the CDISC SEND extended leadership team. Director of SEND solutions at Instem responsible for all our industry leading SEND products and services.