Momelotinib in Transfusion-Dependent Adults With Primary Myelofibrosis (PMF) or Post-polycythemia Vera or Post-essential Thrombocythemia Myelofibrosis (Post-PV/ET MF)

Key Inclusion Criteria:

Diagnosis of PMF or Post PV/ET-MF
Requires myelofibrosis therapy, in the opinion of the investigator
High risk OR intermediate-2 risk defined by dynamic international prognostic scoring system (DIPSS) OR intermediate-1 risk defined by DIPSS and associated with symptomatic splenomegaly and/or hepatomegaly
Transfusion dependent at baseline, defined as ≥ 4 U red blood cell (RBC) transfusion in the 8 weeks prior to first dose of MMB

Acceptable organ function as evidenced by the following:

Platelet Count ≥ 50 x 10^9/L
Aspartate aminotransferase (AST/SGOT) and alanine aminotransferase (ALT/SGPT) ≤ 3 x upper limit of normal (ULN) or AST or ALT ≤ 5 x ULN if liver is involved by disease process as judged by the investigator
Serum creatinine ≤ 2.0 mg/dL or calculated creatinine clearance of ≥ 60 mL/min
Direct bilirubin ≤ 2.0 x ULN
Life expectancy of > 24 weeks
Males and females of childbearing potential who engage in heterosexual intercourse must agree to use protocol specified method(s) of contraception
Lactating females must agree to discontinue nursing before MMB administration
Able to understand and willing to sign the informed consent form

Key Exclusion Criteria:

Prior splenectomy
Splenic irradiation within 3 months prior to the first dose of MMB
Prior treatment with MMB
Known positive status of human immunodeficiency virus (HIV)
Chronic active or acute viral hepatitis A, B, or C infection (testing required for hepatitis B and C), or hepatitis B or C carrier
Use of strong cytochrome P450 3A4 (CYP3A4) inducer within 2 weeks prior to the first dose of MMB
Uncontrolled intercurrent illness per protocol
Treatment with a Janus kinase (JAK) inhibitor within 21 days of the planned first dose of MMB
Presence of peripheral neuropathy ≥ Common Terminology Criteria for Adverse Events (CTCAE) Grade 2
Unwilling or unable to undergo a MRI per requirements in the study protocol
Unwilling to consent to genomics sampling

Note: Other protocol defined Inclusion/Exclusion criteria may apply.