Pacritinib Versus Best Available Therapy to Treat Patients With Myelofibrosis and Thrombocytopenia

Inclusion Criteria:

Intermediate -1 or -2 or high-risk Myelofibrosis (per Passamonti et al 2010)
Thrombocytopenia (platelet count ≤ 100,000/µL) at any time after signing informed consent
Palpable splenomegaly ≥ 5 cm on physical examination
Total Symptom Score ≥ 13 on the MPN-SAF TSS 2.0, not including the inactivity question
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
At least 6 months from prior splenic irradiation
At least 1-4 weeks since prior myelofibrosis therapy, including any erythropoietic or thrombopoietic agent
Not pregnant, not lactating, and agree to use effective birth control
Able and willing to undergo frequent MRI or CT assessments and complete symptom assessments using a patient-reported outcome instrument

Exclusion Criteria:

Prior treatment with more than 2 JAK2 inhibitors or with pacritinib
There is no maximum cumulative prior JAK2 inhibitor treatment
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
Active bleeding that requires hospitalization during the screening period
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