I have had a similar story to yours, Karinne. I've had several PE's, and I've never had any obvious symptoms with them. I could not stay off the Sprycel long enough to get COMPLETELY, 100% free of the effusions, as my PCR rose pretty rapidly each time. I had a couple of PE's on 70 mg and again on 50 mg. The last time I was able to eke out 11 weeks' holiday before returning, and the PE was ALMOST but not quite all gone. This time I returned on 20 mg and have had 0.005% IS PCR's since about March. The PE is still there but small and stable, although the last re-check showed just a smidge of an increase. I am trying so hard to hang onto Sprycel because, despite the alleged low SE profile, there are tons of horror stories out there about bosutinib of continuing debilitating diarrhea and nausea that requires medication to manage. I had all that on Gleevec 9 years ago - no thanks! NOT returning to those problems.
But the real question is, for you and for me and others coming along this PE/Sprycel path: Where are the rock-solid data that say you will become and remain pleural effusion-free if you switch from dasatinib to bosutinib? The main off-target kinase inhibition with bosutinib are the SRC kinases, and these are conjectured to be responsible for fluid problems, like pleural effusions. Trey, on the LLS forum, advises people with PE's on dasatinib to NOT switch to bosutinib (by his admission, he is not a doctor). My own doctor is vague - says his switchers are by and large happy and don't have "problems with pleural effusions." But when I ask if they have x-ray documentation that the PE's are gone and don't come back, he pretty much doesn't know, since that's someone else's lookout, not his. (That's the way we do things here in the US health care system - exasperated sigh. He does CML, someone else does SE's, but they don't know anything about CML, and nobody talks to each other, so they never learn. Next patient, please)
My pulmonolgist is OK with my walking around with an asymptomatic small effusion, so that's the way I'm handling it now. I don't like the idea of getting 2 chest x-rays a year for the next 20-30 years, however. It's just I will not switch to bosutinib until somebody can prove to me that it will improve my PE situation. I agree with your plan to wait as long as you possibly can to let the PE clear completely. When you go back (IF you go back?) I would try 20 mg. If you decide to switch to bosutinib, please keep us posted as to how that works out!
