Polycythemia vera, or PV, is a rare, chronic blood cancer in which a person’s body makes too many red blood cells, white blood cells, and platelets. PV is part of a group of diseases called myeloproliferative neoplasms (MY-ah-lo-pro-LIF-er-uh-tiv NEE-o-plaz-uhms), or MPNs.
Too many red blood cells can cause the blood to thicken. Thicker blood doesn’t flow normally through arteries and veins.
Although PV can occur in persons of any age, it is more common later in life. The average age when a person is diagnosed with PV is 60 years. PV affects slightly more men than women.
About 100,000 people in the United States live with PV. Some PV patients have an inadequate response to or intolerance of hydroxyurea.
PV can be managed. Treatments are available that may help people keep their blood counts under control. However, PV is a chronic, progressive disease. That means it doesn’t go away and is likely to get worse over time. In a very small number of people, PV leads to other blood diseases, such as myelofibrosis (a disease in which scar tissue develops in the bone marrow) or leukemia. This potential for disease transformation is one reason why it is important to track and monitor your condition and engage in regular conversations with your Healthcare Professional. Learn more
No one knows exactly what causes PV. Evidence suggests that proteins known as Janus kinases, or JAKs, are involved. JAK proteins send signals that affect the production of blood cells in the bone marrow. When JAKs send too many signals, they cause the bone marrow to make too many blood cells. This is called overactive signaling. Overactive JAK signaling is a key contributor to the development of PV.
Scientists think that overactive JAK signaling may be related to changes in the genes that make JAK proteins. These changes are called mutations. Almost everyone with PV has a mutation of the Janus kinase 2 (JAK2) gene. Even if you don’t have the JAK2 mutation, you still can have PV.
In addition to making too many blood cells, overactive JAK signaling may result in the overproduction of certain proteins called cytokines (SIGH-toe-kines) in people with PV. Cytokines can cause inflammation. When your body has too many of these proteins, you may experience various symptoms related to PV.
Normal Signaling
Overactive Signaling
Your Healthcare Professional may do a blood test to see if you have a mutation, or change, in a gene that may cause PV.
PV affects each person differently. Some patients with PV have an enlarged spleen. Your spleen helps your body fight infection and filters unwanted material, such as old or damaged blood cells. The increased number of blood cells caused by PV makes your spleen work harder than normal. This may cause the spleen to get bigger.
Learn more about spleen enlargement in people with PV
Some people with PV have no symptoms. In others, PV symptoms can be more severe. It is important to tell your Healthcare Professional about any symptoms you have, even if you are not sure they are related to your PV.
Some people with PV have no symptoms. In others, PV symptoms can be more severe. It is important to tell your Healthcare Professional about any symptoms you have, even if you are not sure they are related to your PV.
Talking to your Healthcare Professional about your symptoms helps you both:
In PV, a person’s body produces an abnormal number of blood cells. This may include red blood cells, white blood cells, and platelets. Hematocrit (HCT) is a measure of the volume of red blood cells in the blood and is stated as a percentage. Keeping HCT at the right levels—usually below 45%—is an important goal in managing PV.
In a specific population of patients taking HU at the maximum tolerated dose and utilizing phlebotomy (a medical procedure that reduces blood counts by removing some blood from the body), certain aspects of your condition may warrant a conversation with your Healthcare Professional about a possible change to your current PV management approach.
These factors may include:
Know 5 key questions you should be asking yourself before your next PV care visit.
Download Polycythemia Vera, Spleen Size & You
Because PV is a progressive condition, it may change over time. That’s why keeping ongoing, detailed information about the various aspects of your condition can help you take an active role in managing your own care. Regularly monitoring various aspects of your PV, including blood counts and the frequency of certain medical procedures (such as phlebotomy), can help you spot trends in your health that may warrant a conversation with your Healthcare Professional.
In some patients with PV, enlargement of the spleen may be a sign of disease progression, which means that your PV may be changing or getting worse. It’s important to work with your care team to regularly keep track of any changes in your spleen size (as identified by your Healthcare Professional) and PV symptoms—including spleen-related symptoms. Talk with your Healthcare Professional about establishing your individual “baseline” spleen size as early on as possible—ideally, at diagnosis—and ask to have your spleen size checked on a regular basis, throughout your PV journey. Be sure to keep notes for yourself to document and keep track of any changes over time.
Remember, regular tracking over time may help you discover important insights that can help you and your Healthcare Professional better understand the state of your PV—and ensure that your current treatment approach is the right one for you.
Low-dose aspirin and phlebotomy
Low-dose aspirin therapy is often the first treatment for patients with PV. It may be combined with phlebotomy. Phlebotomy is a procedure in which your blood cell counts are lowered by removing blood from your body.
Hydroxyurea, or HU, a type of chemotherapy
Patients with PV who have difficulty tolerating phlebotomy, have splenomegaly (an enlarged spleen), or who have elevated blood counts may be candidates for HU, a chemotherapy medicine that reduces the number of red blood cells (RBCs), white blood cells (WBCs), and platelets.
Jakafi is the first FDA-approved treatment for adults with PV who have already taken a medicine called hydroxyurea and it did not work well enough or they could not tolerate it.
Jakafi is a targeted treatment that works to help keep the production of blood cells under control. It is not chemotherapy.
At your next appointment, ask about your current hematocrit level and whether your PV is under control. If your Healthcare Professional is having trouble keeping your hematocrit in your target range using HU, it may be a sign of resistance to HU.
Please see the Full Prescribing Information, which includes a more complete discussion of the risks associated with Jakafi.
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Jakafi is a prescription medicine used to treat adults with polycythemia vera who have already taken a medicine called hydroxyurea and it did not work well enough or they could not tolerate it.
Jakafi is used to treat adults with certain types of myelofibrosis.
Jakafi is used to treat adults and children 12 years of age and older with acute graft-versus-host disease (GVHD) who have taken corticosteroids and they did not work well enough.
Jakafi is also used to treat adults and children 12 years of age and older with chronic GVHD who have taken one or two types of treatments and they did not work well enough.
Jakafi can cause serious side effects, including:
Low blood counts: Jakafi® (ruxolitinib) may cause low platelet, red blood cell, and white blood cell counts. If you develop bleeding, stop taking Jakafi and call your healthcare provider. Your healthcare provider will do a blood test to check your blood counts before you start Jakafi and regularly during your treatment. Your healthcare provider may change your dose of Jakafi or stop your treatment based on the results of your blood tests. Tell your healthcare provider right away if you develop or have worsening symptoms such as unusual bleeding, bruising, tiredness, shortness of breath, or a fever.
Infection: You may be at risk for developing a serious infection during treatment with Jakafi. Tell your healthcare provider if you develop any of the following symptoms of infection: chills, nausea, vomiting, aches, weakness, fever, painful skin rash or blisters.
Cancer: Some people have had certain types of non-melanoma skin cancers during treatment with Jakafi. Your healthcare provider will regularly check your skin during your treatment with Jakafi. Tell your healthcare provider if you develop any new or changing skin lesions during treatment with Jakafi.
Increases in cholesterol: You may have changes in your blood cholesterol levels during treatment with Jakafi. Your healthcare provider will do blood tests to check your cholesterol levels about every 8 to 12 weeks after you start taking Jakafi, and as needed.
Increased risk of major cardiovascular events such as heart attack, stroke or death in people who have cardiovascular risk factors and who are current or past smokers while using another JAK inhibitor to treat rheumatoid arthritis: Get emergency help right away if you have any symptoms of a heart attack or stroke while taking Jakafi, including: discomfort in the center of your chest that lasts for more than a few minutes, or that goes away and comes back, severe tightness, pain, pressure, or heaviness in your chest, throat, neck, or jaw, pain or discomfort in your arms, back, neck, jaw, or stomach, shortness of breath with or without chest discomfort, breaking out in a cold sweat, nausea or vomiting, feeling lightheaded, weakness in one part or on one side of your body, slurred speech.
Increased risk of blood clots: Blood clots in the veins of your legs (deep vein thrombosis, DVT) or lungs (pulmonary embolism, PE) have happened in people taking another JAK inhibitor for rheumatoid arthritis and may be life-threatening. Tell your healthcare provider right away if you have any signs and symptoms of blood clots during treatment with Jakafi, including: swelling, pain, or tenderness in one or both legs, sudden, unexplained chest or upper back pain, shortness of breath or difficulty breathing.
Possible increased risk of new (secondary) cancers: People who take another JAK inhibitor for rheumatoid arthritis have an increased risk of new (secondary) cancers, including lymphoma and other cancers. People who smoke or who smoked in the past have an added risk of new cancers.
The most common side effects of Jakafi include: for certain types of myelofibrosis (MF) and polycythemia vera (PV) – low platelet or red blood cell counts, bruising, dizziness, headache, and diarrhea; for acute GVHD – low platelet counts, low red or white blood cell counts, infections, and swelling; and for chronic GVHD – low red blood cell or platelet counts and infections including viral infections.
These are not all the possible side effects of Jakafi. Ask your pharmacist or healthcare provider for more information. Call your doctor for medical advice about side effects.
Before taking Jakafi, tell your healthcare provider about: all the medications, vitamins, and herbal supplements you are taking and all your medical conditions, including if you have an infection, have or had low white or red blood cell counts, have or had tuberculosis (TB) or have been in close contact with someone who has TB, had shingles (herpes zoster), have or had hepatitis B, have or had liver or kidney problems, are on dialysis, have high cholesterol or triglycerides, had cancer, are a current or past smoker, had a blood clot, heart attack, other heart problems or stroke, or have any other medical condition. Take Jakafi exactly as your healthcare provider tells you. Do not change your dose or stop taking Jakafi without first talking to your healthcare provider.
Women should not take Jakafi while pregnant or planning to become pregnant. Do not breastfeed during treatment with Jakafi and for 2 weeks after the final dose.
Please see the Full Prescribing Information, which includes a more complete discussion of the risks associated with Jakafi.
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.
You may also report side effects to Incyte Medical Information at 1-855-463-3463.
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