Myeloproliferative neoplasms, better known as MPNs, are rare and chronic type of blood cancers that develop when the body makes too many red blood cells, white blood cells, or platelets. MPNs are a type of blood cancer that gets worse with time, and because they are chronic, they can last for many years.
Changes in some genes (genetic mutations) are believed to be a major reason for the development of MPNs, although people without such mutations can also have this type of malignancy.
These cancers are estimated to affect 200,000 individuals in the United States. Recognizing the signs of these conditions may ensure early diagnosis. And knowing which type of MPN you have is important to ensure you receive the best available treatment.
The 3 types of MPNs are polycythemia vera, essential thrombocythemia, and myelofibrosis.
The 3 Types of MPNs
Polycythemia vera is the most common type of these 3, affecting approximately 100,000 Americans. The cause for polycythemia vera is unknown, but a change (mutation) in the JAK2 gene is found in 95% of patients with polycythemia vera and is believed to be a cause for this type of cancer.
Although some patients with this cancer have no symptoms, the common symptoms of polycythemia vera include:
- Unexpected weight loss
- Bone pain
- Bleeding or clotting.
This cancer is more common in people 50 and older than in younger persons, and is slightly more common in women than in men; but young people can also get this cancer.
The common symptoms of essential thrombocythemia include:
- Vision changes.
Myelofibrosis occurs when too much scar tissue forms in the bone marrow and damages its ability to produce normal blood cells. Myelofibrosis can develop on its own for no clear reason, or it can develop when polycythemia vera or essential thrombocythemia gets much worse.
Approximately 16,000 to 18,000 people in the United States are affected by myelofibrosis. And about 50% to 60% of patients with myelofibrosis have the JAK2 genetic mutation. Another mutation related to the JAK2 gene may also be involved in some patients.
The symptoms of myelofibrosis include:
- Bone pain
- Night sweats
- Unexplained weight loss.
Impact on Quality of Life
The 2016 MPN Landmark survey of more than 800 patients with MPNs showed that these chronic conditions can reduce the patient’s quality of life significantly. In this survey, 79% of patients with myelofibrosis, 63% of patients with polycythemia vera, and 55% of patients with essential thrombocythemia reported that their cancer reduced the quality of their family life and social life. In addition, patients had to cancel planned activities, and even call in sick to work because of their disease.
Treatment for Myeloproliferative Neoplasms
All patients with MPNs should be routinely monitored by their doctor to prevent the common complications associated with these types of cancers.
Polycythemia Vera Treatment
Treatment options for polycythemia vera include:
- Removal of blood (phlebotomy) to reduce the excess blood cells
- Low-dose aspirin therapy
- Chemotherapy, such as hydroxyurea
- Jakafi (ruxolitinib), which is the first and only drug approved by the FDA for polycythemia vera.
Jakafi is prescribed for patients whose disease did not improve with hydroxyurea, or for patients who could not tolerate hydroxyurea. Jakafi works by blocking proteins that control the production of blood cells.
A recent study showed that patients with polycythemia vera whose disease was resistant to or intolerant of hydroxyurea and who did not have an enlarged spleen had better control of their blood levels with Jakafi, without needing phlebotomy.
Almost 5 times more patients with polycythemia vera were in remission after receiving Jakafi compared with patients who received best available therapy.
Essential Thrombocythemia Treatment
The treatments for essential thrombocythemia may include drugs or procedures to reduce the platelet count.
Jakafi is also the first and only drug approved by the FDA for the treatment of patients with intermediate- or high-risk myelofibrosis. The treatments for myelofibrosis include Jakafi, blood transfusions, radiation, removal of the spleen, and stem-cell transplantation.
In 2016, a new study showed that Jakafi reduced the risk for death by 31% and reduced the spleen volume by 35% in patients with myelofibrosis.
“Nearly 5 years after the launch of Jakafi for the treatment of intermediate- and high-risk MF [myelofibrosis], these findings provide important insight into the treatment’s long-term clinical benefits. The overall survival benefit observed in the COMFORT-I study, along with sustained reductions in spleen volume, are meaningful for patients with this rare disease who often experience significant, debilitating symptoms, and even mortality, as a result of their disease,” said Steven Stein, MD, Chief Medical Officer at Incyte, the drug company that developed Jakafi.