Ruxolitinib and Pracinostat Combination Therapy for Patients With Myelofibrosis (MF)

Study Drug Administration: If you are found to be eligible to take part in this study, you will take ruxolitinib by mouth 2 times each day. You may take your dose of ruxolitinib with or without food. You will also take pracinostat by mouth 1 time each day for 3 alternating days (for example Monday, Wednesday, Friday or Tuesday, Thursday, Saturday) every 3 weeks starting on Day 1 of Cycle 4. You will take your dose of pracinostat in the morning, about 30 minutes before or 2 hours after a meal. You should swallow your dose of pracinostat whole with a cup of water (about 8 ounces). You will be given a study drug diary to write down when you take your dose of study drugs and if you miss or vomit any doses of study drug. You must bring the diary with you to the clinic on Day 1 of each cycle and at the end-of-treatment visit. You will also need to bring any leftover pills and any empty containers of the study drugs to the clinic when the study doctor tells you to do so. Study Visits: There are 28 days (4 weeks) in every study cycle. You will visit MD Anderson for regular study visits while participating in this study during Cycles 2-7, and then once every 3 cycles after that (Cycles 10, 13, 16, and so on). Once during Cycles 2-7 and then once every 3 cycles after that (Cycles 10, 13, 16, and so on): * You will have a physical exam. * You will complete the questionnaire about your quality of life. At your visits during Cycles 4, 5, and 6 and then once every 3 cycles starting with cycle 10 (cycles 10, 13, 16 and so on): You will have an EKG to check your heart function. At your visits during Cycles 4, 5, and 7 and then every 3 cycles after that (Cycles 10, 13, 16, and so on) blood (about 1-2 teaspoons) will be drawn for cytokine testing. At your visits during Cycles 7 and 13, and then every 6 cycles after that (Cycles 19, 25, 31, and so on), if the doctor thinks it is needed, you will have a bone marrow biopsy to check the status of the disease and for cytogenetic and genetic testing. Every 2 weeks during the first 6 cycles and then about every 3 cycles after that, blood (about 2-3 tablespoons) will be drawn for routine tests. In between the mandatory visits to MD Anderson, you may choose to have these blood draws performed at a local lab or clinic closer to your home. The results will be sent to the study doctor. Length of Treatment: You may continue taking the study drugs for up to 4 years. You will no longer be able to take the study drugs if the disease gets worse, if intolerable side effects occur, or if you are unable to follow study directions. Your participation on the study will be over after the follow-up. Follow-Up: About 30 days after your last dose of study drugs, if you are not receiving another treatment for MF, you will be called by the study doctor or a member of the study staff and asked about any side effects you may be having. This call should last about 10 minutes.