Target Occupancy Study (TOS), page-14

Hi @Ricksanchezc137

Thanks for your reply.

It looks like you didn't have any discussions with Bill about the tracer used by ACW.
The accuracy of the target occupancy percentages depend on the affinity and specificity of the tracer used.

As far as I can see, there seem to be two tracers for 11β-HSD1:
* the Merck tracer which was used in monkeys in 2011 and in humans for the first time in 2018-9 (by ACW)
* [11C]-AS2471907, which was discovered in 2016 and was alleged to be more specific than previous tracer(s). It was first used in humans in 2019 (not by ACW)

If a tracer isn't specific to the target of interest, it can bind to the wrong enzyme (as well as to the target) and give misleadingly high readings.

This is a different issue than what level of occupancy is required for cognitive efficacy.

If you want to research more about tracers for 11β-HSD1, please follow the links which I posted above.

Regards

II