Oral Pacritinib Versus Best Available Therapy to Treat Myelofibrosis

Inclusion Criteria:

• Intermediate -1 or -2 or high-risk Myelofibrosis (per Passamonti et al 2010)
• Palpable splenomegaly ≥ 5 cm on physical examination
• Score ≥ 3 for at least two symptoms on the MPN-SAF TSS or score ≥ 4 for at least one symptom on MPN-SAF TSS other than fatigue
• Patients who are platelet or red blood cell transfusion-dependent are eligible
• Adequate white blood cell counts (with low blast counts), liver function, and renal function
• No spleen radiation therapy for 6-12 months
• Last therapy for myelofibrosis was 2-4 weeks ago, including any erythropoietic or thrombopoietic agent
• Not pregnant, not lactating, and agree to use effective birth control

Exclusion Criteria:

• Prior treatment with a JAK2 inhibitor
• History of (or plans to undergo) spleen removal surgery or allogeneic stem cell transplant
• Ongoing gastrointestinal medical condition such as Crohn's disease, Inflammatory bowel disease, chronic diarrhea, or constipation
• Cardiovascular disease, including recent history or currently clinically symptomatic and uncontrolled: congestive heart failure, arrhythmia, angina, QTc prolongation or other QTc risk factors, myocardial infarction
• Other malignancy within last 3 years other than certain limited skin, cervical, prostate, breast, or bladder cancers
• Other ongoing, uncontrolled illnesses (including HIV infection and active hepatitis A, B, or C), psychiatric disorder, or social situation that would prevent good care on this study
• Life expectancy < 6 months