Having had a look at it, it seems like this involves a molecule (Q2361) closely related to tacrolimus that is capable of binding to FKBP12 where tacrolimus woul

Having had a look at it, it seems like this involves a molecule (Q2361) closely related to tacrolimus that is capable of binding to FKBP12 where tacrolimus would normally bind but without affecting the function of FKBP12.[1] This seems to be useful in the specific case of people on long term tacrolimus as it locally antagonises tacrolimus activity in the skin to reduce cancer risk. [1] https://jitc.bmj.com/content/jitc/11/9/e006783.full.pdf https://jitc.bmj.com/content/jitc/11/9/e006783.full.pdf