Polycythemia vera (PV) is a rare, chronic type of cancer (leukemia) that affects an estimated 44 to 57 per 100,000 individuals in the United States.1

PV is associated with mutations in the in the JAK2 gene. Although it remains unclear exactly what initiates PV, researchers believe that it begins when mutations occur in the DNA of a hematopoietic stem cell.1

PV develops slowly (it may not cause symptoms for many years) and can occur at any age, although it is more common in adults between 50 and 75. Men are more likely to get polycythemia vera, but women tend to get the disease at younger ages.2

PV is characterized by an increased number of red blood cells produced in the bone marrow. Affected individuals may also have excess white blood cells and blood clotting cells called platelets.1

The extra blood cells and platelets cause the blood to be thicker than normal,1 increasing the risk of heart attack, stroke, pulmonary embolism (blockage of an artery in the lungs) and accumulation of extra blood cells in the spleen, causing it to swell.3


The IMPRSSION clinical trial is currently enrolling eligible adults to evaluate the safety and effectiveness of an investigational antisense drug for people living with PV.

  1. National Library of Medicine. MedlinePlus. Polycythemia vera. 2013. Available at https://medlineplus.gov/genetics/condition/polycythemiavera/# causes. Accessed September 13, 2022.
  2. Mayo Clinic. Polycythemia vera. 2022. Available at https://www.mayoclinic.org/diseases-conditions/polycythemia-vera/symptoms-causes/ syc-20355850#:~:text=Polycythemia%20vera%20(pol%2De%2D,Polycythemia%20vera%20is%20rare. Accessed September 13, 2022.
  3. Leukemia & Lymphoma Society. Polycythemia Vera. Available at https://www.lls.org/myeloproliferative-neoplasms/polycythemia-vera. Accessed September 13, 2022.