Safety and Efficacy of Momelotinib in Subjects With Polycythemia Vera or Essential Thrombocythemia

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 inducers within 1 week prior to the first dose of study drug

- QTc interval > 450 msec, unless attributed to bundle branch block