Reversal of myelofibrosis by hydroxyurea.

Bone marrow morphology in 39 symptomatic patients with myeloproliferative disorders (polycythaemia vera 15, essential thrombocythaemia 14, idiopathic myelofibrosis 9, myeloproliferative syndrome 1) and elevated platelet counts was studied before and after a median of 18 months of continuous treatment with hydroxyurea. We found a significant reduction of bone marrow fibrosis, believed to be mediated by suppression of thrombopoiesis by hydroxyurea.