Clinical Trials

Inclusion Criteria:

• Diagnosis of either PV or ET as defined by the 2008 World Health Organization (WHO) Diagnostic Criteria
• Requires treatment for PV or ET, in the opinion of the study investigator
• Intolerant of, resistant to, or refuses current or available treatment for PV or ET
• Direct bilirubin ≤ 2.0 x upper limit of the normal range (ULN)
• Aspartate transaminase (AST) and alanine transaminase (ALT) ≤ 3 x ULN
• Calculated creatinine clearance (CrCl) of ≥ 45 mL/min
• Life expectancy > 24 weeks
• Male subjects and female subjects of childbearing potential who engage in heterosexual intercourse must agree to use protocol specified method(s) of contraception
• Females who are nursing must agree to discontinue nursing before the first dose of study drug
• Able to comprehend and willing to sign informed consent form

Exclusion Criteria:

• Prior splenectomy
• Uncontrolled intercurrent illness, per protocol
• Known positive status for human immunodeficiency virus (HIV)
• Chronic active or acute viral hepatitis A, B, or C infection, or hepatitis B or C carrier
• Myeloproliferative neoplasm-directed therapy, other than aspirin, hydroxyurea, anagrelide, and/or phlebotomy, within 21 days prior to the first dose of study drug
• Anagrelide within 7 days prior to the first dose of study drug
• Presence of peripheral neuropathy ≥ Grade 2
• Unwilling or unable to take oral medication
• Prior use of a JAK1 or JAK2 inhibitor
• Use of strong CYP3A4 inhibitors or strong inducers CYP3A4 within 1 week prior to the first dose of study drug
• QTc interval > 450 msec, unless attributed to bundle branch block