Does stopping anagrelide affect fibrosis in patients with ET who develop post-ET myelofibrosis?

Anagrelide is a phosphodiesterase (PDE) III inhibitor, developed initially as a platelet antiaggregant, but was found to have platelet lowering activity at concentrations lower than its platelet antiaggregant activity. Thus, it was consequently marketed to reduce thrombocytosis in MPN patients. It is thought to act by specifically inhibiting thrombopoietin-mediated signaling in megakaryocytes. As a potent phosphodiesterase (PDE) III inhibitor, it also has significant ionotropic, chronotropic and vasodilatory effects, making it difficult to tolerate by many patients. Less well recognized, particularly in the elderly, are its ability to cause cardiac failure, fluid retention, hypertension, renal failure, and pneumonitis. It was more effective...