This is a very good point. A bit of a catch 22 here in a way. If company can't test for PD1 via blood due to drop in CTCs, frequent testing will be prohibitive and too risky in these sick patients.

On the other hand, if leronlimab dramatically lowers CTCs by itself, are there any other drugs currently that can do this with no side effects. Seems like that should be getting as much attention as the PD1 induction.