OMG, my medical plan changed so I lost my hematologist after 10 years on Anagrelide. New guy was SHOCKED, said I should definitely be switched to hydroxyurea and attempted a very lengthy, painful bone marrow biopsy which ultimately provided nothing unusual. Biopsy had never been done since the Agrylin (pre-generic anagrelide, may have been brand new) did the trick lowering platelets from 1800+ to below 400 quickly. So after five pokes (I remember asking if he'd ever done this procedure on a live person) my medication was switched awaiting results. A nightmarish 6 weeks of weekly out of control blood draw results. Took me that long to get approval for a DIFFERENT provider who basically said, if it works, why change it? So...I'm probably heading to 25+ years without symptoms from ET. I may have been an anomaly with the hydroxyurea, impatient since there hadn't been any symptoms or might have been an over enthusiastic new doctor. Thanks for asking.