Assessing Feasibility of Thromboprophylaxis With Apixaban in JAK2-positive Myeloproliferative Neoplasm Patients

Myeloproliferative neoplasms (MPNs) are blood disorders that occur when the body makes too many white or red blood cells, or platelets. This overproduction of blood cells in the bone marrow can create problems for blood flow and lead to various symptoms. One of the major problems is the formation of blood clots. These may form in the veins of a patient's legs or arms where they cause leg or arm pain, swelling or difficulty walking. These clots may travel to the lung and then cause chest pain, shortness of breath and sometimes death. Blood clots can also lead to poor or no blood flow to one's heart, brain, or other organs, causing damages that cannot be easily or ever repaired, such as stroke or heart attack. Patients diagnosed with certain types of MPN are associated with a higher risk of developing blood clots and related complications. For this reason, MPN patients are usually treated with low-dose aspirin, a common drug used for blood clot prevention, on long-term basis to prevent the formation of blood clots and other complications. However, recent studies also show that the risk of blood clots remains elevated in MPN patients treated with aspirin, and there may not be improvement or reduction in fatal or other events that are associated with blood clots. In addition, since this medical condition is rare, so there's a lack of studies done with high quality results to help physicians decide the best treatment plan for these patients. The study drug, apixaban, is a new type of orally-taken blood thinner that has been shown to be effective and safe for prevention and treatment of blood clots in various patient populations. The investigators will evaluate whether apixaban is safer and/or better at preventing blood clots and other complications in MPN patients compared to aspirin.