Hi Stark,
Thanks for clarifying.
I'm not sure if can be done. Currently the issue is that your main object is Test Cases but your narrow down is a filter on Defects (cause you need to filter out defects with certain descriptions).
I don't know that you can make such a 'join' of two main objects.
Yet, let me be more certain I still get what you're trying to find out here:
Your Defects include their Test Case IDs in their Description field, i.c: TC1111, TC1112, TC1113 . Your query returns the failing test cases un-associated to defects. So, are you suggesting that if a Test Case ID is in a Defect's description field then it should be treated 'as if' it's associated to that defect and hence filtered out?
Sagi