There is no regulation when this has to be done, but FDA recommends early in the development process:
We encourage the identification of any differences in drug metabolism between animals used in
nonclinical safety assessments and humans as early as possible during the drug development
process.8,9 The discovery of disproportionate drug metabolites late in drug development can
potentially cause development and marketing delays (from guidance on safety of metabolites)
Personally, if choice, i would do before the EOP2 as one: may generate more questions that you need answered ( need for renal impaired studies, hepatic impairment studies) and 2) the answers you get for the questions you have now may not be relevant once you do your mass balance study.
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Robert Blanks RAC
VP, Regulatory Affairs and Quality Assurance
[Ardelyx]
Auburndale MA
United States
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Original Message:
Sent: 10-Jul-2019 11:21
From: Anonymous Member
Subject: End of Phase 2 Meeting
This message was posted by a user wishing to remain anonymous
Dear Experts,
There is an internal debate happening in my company regarding the mass balance study. Should a sponsor have conducted the human mass balance study before the end-of-phase 2 meeting?
Thank you for any advice - it is greatly appreciated.