Sorry to hear that your cancer returned. Unfortunately, that is a nasty habit of bladder cancer. There is a lot of information about similar clinical trials available....Google:
Trial of Inravesical (BCG) in Combination with ALT-803 in Patients with High Grade Non-Muscle Invasive Bladder Cancer)
and you can see many on-going trials and some reports of finished ones. Of course, it would be hard to tell which one you might be thinking of joining,
Some questions I always ask when considering a clinical trial (and I have been on both sides...as a patients and as a part of the trial design):
Is the purpose of this trial to study effectiveness? (Sometimes...not in this case...the initial purpose is just to see if humans tolerate the substance)
Is this a blind trial? (for example, will half the patients receive JUST BCG and the other half BCG plus the study drug or will all the patients receive the study drug?)
How will I be followed after the trial ends?
What are the possible known side effects?
I am sure that you can think of other questions, but these are a start.
If you do join this trial, please keep us informed about how it goes. So many people never have the opportunity to be part of a good clinical trial and would be interested in following your adventure!
Sara Anne