Pacritinib Before Transplant for Myeloproliferative Neoplasms (MPN)

Study Drug Administration:

If you are found to be eligible to take part in this study, you will take pacritinib at about
the same time each day by mouth, 2 times each day. Your doctor will tell you when to start
and stop taking pacritinib. You may be able to take the drug for about 2-6 months depending
on how you tolerate the drug and when your transplant date is. If you do not receive your
transplant, you may be able to continue taking the study drug as long as the doctor thinks it
is in your best interest.

You must swallow the capsules whole with a glass (about 8 ounces) of water. Do not open,
break, or chew the capsules.

If you vomit or miss a dose of pacritinib, take your next dose of pacritinib at your regular
time. Do not "make up" a missed or vomited dose.

You will be given a study drug diary to write down what time you take each dose of
pacritinib. You need to bring the study drug diary, any leftover study drug, and any empty
study drug containers with you to each study visit.

The dose of pacritinib you receive may be lowered or stopped, if the doctor thinks it is
needed.

About 21 days after your last dose of pacritinib, you will given standard of care drugs and
you will have an allogeneic stem cell transplant. Your doctor will explain this treatment and
the stem cell transplant to you in more detail. You will be required to sign a separate
consent form.

Study Visits:

One (1) time each month:

- You will have a physical exam.

- Blood (about 2 teaspoons) will be drawn for routine tests and to check your kidney and
liver function.

- You will have an electrocardiogram (EKG -- a test that measures the electrical activity
of the heart).

On Day 14 (+/- 2 days) of of Cycle 1, blood (about 2 teaspoons) will be drawn for routine
tests and to check your kidney and liver function. You can have this blood drawn at a local
lab or clinic that is closer to your home. The results will be sent to the study doctor at MD
Anderson.

During Week 2 of Cycle 1, a member of the study staff will call to ask you about any symptoms
you may be having. This call should last about 5-10 minutes.

Length of Study:

You will be on study for up to 1 year after the transplant. You may be taken off study early
if the disease gets worse, if you have any intolerable side effects, of if you are unable to
follow study directions.

Your participation on this study will be over after about 1 year of follow-up tests.

End-of-Study Visit:

Within about 7 days after your last dose of pacritinib, but before your stem cell transplant:

- You will have a physical exam and an ultrasound, MRI, or CT scan of your abdomen to
measure your liver and spleen.

- You will have an EKG.

Before your transplant, you will have a bone marrow biopsy/aspiration to check the status of
the disease.

Follow-Up Tests:

You will have follow-up visits at about 1, 3, 6, and 12 months after the transplant:

- You will complete 3 questionnaires about your symptoms and quality of life. It should
take about 20-30 minutes to complete the questionnaires.

- At Month 3, you will have a physical exam and an ultrasound, MRI, or CT scan of your
abdomen to measure your liver and spleen. This will be repeated at Month 12, if your
doctor thinks it is needed.

- At Months 3 and 12, you will have a bone marrow biopsy/aspiration to check the status of
the disease.

This is an investigational study. Pacritinib is not FDA approved or commercially available.
It is currently being used for research purposes only. The study doctor can explain how the
study drug is designed to work.

Up to 40 participants will be enrolled in this study. All will take part at MD Anderson.

Inclusion Criteria:

1. Patients with Idiopathic Myelofibrosis or Myelofibrosis secondary to Polycythemia Vera
or Essential Thrombocythemia.

2. Patients 18 years to less than or equal to 70 years.

3. Patients wanting to pursue transplant.

4. Patients must have a Zubrod PS equal or less than 2.

5. Calculated creatinine clearance greater than 50ml/min. using the Cockcroft-Gault
equation.

6. Ejection fraction equal or above 40%.

7. Serum direct bilirubin less than 1 mg/dl (unless due to Gilbert's syndrome or
hemolysis).

8. SGPT equal or less than 4 x normal values.

9. Corrected DLCO equal or above 50% of expected.

10. Negative Beta HCG test in a woman with childbearing potential defined as not
post-menopausal for 12 months or no previous surgical sterilization) and if fertile,
males and females must agree to use contraceptives.

Exclusion Criteria:

1. Patients with low risk myelofibrosis.

2. Uncontrolled life-threatening infections.

3. HIV positive.

4. Patients with active viral hepatitis.

5. Prior treatment with Pacritinib.

6. Prior stem cell transplant.

7. QTc greater than 450 ms.

8. CYP3A4 strong or moderate inhibitors/inducers in the past 7 days.