Bind variables are a documented feature of Toad Edge (https://support.quest.com/technical-documents/toad-edge/2.0.9/user-guide/8#TOPIC-1189222).
A simple query with a bind variable works in 2.0.2:
We have been upgraded to 2.0.9, where this fails with an error:
ERROR: syntax error at end of input Position: 9
Execution Started: 16:26:59
Execution Time: 0 ms