A Study of Anagrelide Controlled Release (GALE-401) in Patients With High Platelet Counts Due to Bone Marrow Disorders

Inclusion Criteria: 1. Provide written informed consent prior to any study specific procedure 2. Male or female patients aged ≥ 18 years 3. Diagnosis of a myeloproliferative neoplasm (i.e., chronic myelogenous leukemia (CML), polycythemia vera (PV), primary myelofibrosis (PMF), essential thrombocythemia (ET)) as determined by the treating physician, such as based on the 2008 World Health Organization (WHO) classification of myeloid malignancies 4. Baseline platelet count ≥600 x 10e9/L as determined on two occasions at least 14 days apart prior to the first dose of study drug 5. Requirement for platelet reduction therapy as assessed by the Investigator 6. Currently not receiving therapy specifically intended to reduce platelet counts 7. For patients with ET, prior platelet lowering therapy (e.g., hydroxyurea, anagrelide or interferon) may not be administered within 2 weeks prior to the first dose of study drug. For patients with MPN diagnoses other than ET, concurrent anti-MPN treatment is permitted provided that the treatment has been administered at stable doses for at least 4 weeks prior to the first dose of study drug. Examples of permitted medications include but are not limited to hydroxyurea for PV, ruxolitinib for MF, and imatinib for CML. All patients must have discontinued anagrelide at least 2 weeks prior to the first dose of study drug. EXCEPTION: busulfan, melphalan and phosphate P-32 must have been discontinued at least 4 weeks prior to the first dose of study drug. 8. Adequate hepatic function defined as bilirubin ≤1.5 x ULN, INR ≤1.5 x ULN, albumin \>3.5 g/dL, ALT \< 3.0 x ULN, AST \< 3.0 x ULN 9. If female, must be of non-childbearing potential, i.e. post- menopausal (defined as \> 12 months since last menstrual period) or surgically sterilized (i.e. tubal ligation or hysterectomy at least 6 months prior to screening) or, if of childbearing potential, must not be pregnant or nursing 10. Males and females of child bearing must agree to use an acceptable form of birth control until 28 days following the last dose of study drug Exclusion Criteria: 1. Other MPN diagnoses not specifically included above: Chronic neutrophilic leukemia, chronic eosinophilic leukemia, mastocytosis, and unclassifiable MPNs 2. Previously found to be refractory to anagrelide therapy (i.e., failure to achieve a platelet count \<600 x 10e9/L for reasons other than anagrelide-related toxicity) 3. History of coronary artery disease requiring a revascularization procedure within 3 months prior to screening 4. Left bundle branch block or sustained ventricular tachycardia (\>30 seconds) evident on 12-lead ECG at screening 5. Tachycardia defined as resting heart rate \>100 bpm at screening 6. Unstable angina (characterized by increasingly frequent episodes with modest exertion or at rest, worsening severity, or prolonged duration) within 3 months prior to screening 7. Transient ischemic attack (TIA) or stroke within 3 months prior to screening 8. Unstable or clinically significant concurrent medical condition that would, in the opinion of the Investigator, jeopardize the safety of a subject and/or their compliance with the protocol. 9. Current alcohol or drug abuse, or a significant medical condition that, in the opinion of the Investigator, may impair compliance with the requirements of the protocol 10. History of allergic hypersensitivity to anagrelide or any component of its formulations 11. Administration of Type 3 phosphodiesterase (PDE3) inhibitors (e.g., inamrinone, cilostazol, milrinone) within 2 weeks prior to initiating study treatment 12. Administration of any investigational product within 4 weeks prior to initiating study treatment 13. History of intolerance of other PDE3 inhibitors