After 24 mo of stability study our drug substance/API still meets the acceptance criteria of the stability indicating assessment and that results were not significantly different to what’s on the original CoA. We still could not see when the material is likely to go out of spec and therefore could not propose a shelf life/expiry date. And as such our stability data allows us to extended the retest date. The API is for a non-marketed product and undergoing trials.
In theory, how could we still use this API (same lot used in the stability study) in the future and what would be required - e.g. would extending the stability study be enough?? would an updated CoA with an updated retest date be sufficient or would a new set of testing be required to generate a new CoA prior to release.