Dear Kiruba,
It may well be that you will need to switch to another TKI (dasantib or nilotinib)given that your PH+ cell poplulation has not reduced by any significant % over the last 16 months of therapy with Glivec.
I am sure your doctor is aware that this is interpreted by most cml clinicians as a sub-optimal response which is why I imagine he has increased your dose to 800mg.
It might be a good idea for you to have mutation test to see if you have a Glivec resistant mutation. This would make the picture a little clearer for you. Where are you being treated? Would it be possible for you to get a second opinion?
best wishes,
Sandy