Polycythemia Vera

About Polycythemia Vera


What is polycythemia vera?

Polycythemia vera, or PV, is a rare, chronic, progressive 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.


Who gets PV?

Graphic of line drawing of a man and a woman

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.

Image of a healthcare provider talking with an elderly man

About 100,000 people in the United States live with PV. Some PV patients have an inadequate response to or intolerance of hydroxyurea.


What are the effects of PV over time?

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 1 reason why it is important to track and monitor your condition and engage in regular conversations with your Healthcare Professional. Learn more


What causes PV?

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.

Graphic of Normal Signaling of JAK proteins that affect the production of blood cells in the bone marrow.

Normal Signaling

Graphic of Overactive Signaling of JAK proteins causing the body to make the wrong number of blood cells.

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.


What can happen in the body as a result of PV?

PV affects each person differently. Some patients with PV have an enlarged spleen. Your spleen helps your body fight infection and filter 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.

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.

Graphic of Rx chat icon

Talking to your Healthcare Professional about your symptoms helps you both:

  • Understand how PV is affecting you
  • Follow how your PV is changing over time

What aspects of my PV should be discussed with my Healthcare Professional?

Graphic of <45%/HCT in a circle - An important goal in managing PV is keeping HCT at the right levels—usually below 45%.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:

  • Elevated hematocrit (HCT) levels
  • Higher than normal white blood cell (WBC) counts
  • Low platelet counts
  • Enlarged spleen size
If you are being treated with HU and phlebotomy and you notice that your blood counts are elevated or that you have an enlarged spleen, be sure to have a discussion with your Healthcare Professional about whether or not Jakafi may be a possible treatment option for you.

What aspects of my PV should I be tracking?

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.

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.


What are some treatments for PV?

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 and only FDA-approved treatment for people 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.

Learn how Jakafi works

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.

If you have PV and did not benefit from or cannot tolerate HU, talk with your Healthcare Professional about whether or not Jakafi may be right for you

Please see the Full Prescribing Information, which includes a more complete discussion of the risks associated with Jakafi.

Image of woman – Jakafi patient – talking on the phone, sitting on a park bench

Talk with a patient taking Jakafi

Register for the Incyte Mentor Program and connect with another patient taking Jakafi.

Learn How
Image of man – Jack – sitting with his dog in the desert. Click on the button and watch the video of how Jack explored his treatment options for polycythemia vera after being unable to tolerate hydroxyurea.

Taking Jakafi was right for Jack, who was unable to tolerate hydroxyurea

Learn how Jack’s PV diagnosis and intolerance of hydroxyurea prompted him to talk to his Healthcare Professional about treatment possibilities with Jakafi.

Watch Jack’s Story
connect-patient

Connect With
a Patient
Like Jack

Connect With a
Patient Like Jack

Register for the Incyte Mentor Program and connect with another patient taking Jakafi.

Email Address

Continue Registering

Expand Collapse

Important Safety Information

Indications and Usage

Jakafi is a prescription medicine used to treat people 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 also used to treat certain types of myelofibrosis.

Important Safety Information

Jakafi can cause serious side effects, including:

Low blood counts: Jakafi® (ruxolitinib) may cause your platelet, red blood cell, or white blood cell counts to be lowered. If you develop bleeding, stop taking Jakafi and call your healthcare provider. Your healthcare provider will perform blood tests 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.

Skin cancers: Some people who take Jakafi have developed certain types of non-melanoma skin cancers. Tell your healthcare provider if you develop any new or changing skin lesions.

Increases in cholesterol: You may have changes in your blood cholesterol levels. Your healthcare provider will do blood tests to check your cholesterol levels during your treatment with Jakafi.

The most common side effects of Jakafi include: low platelet count, low red blood cell counts, bruising, dizziness, headache.

These are not all the possible side effects of Jakafi. Ask your pharmacist or healthcare provider for more information. Tell your healthcare provider about any side effect that bothers you or that does not go away.

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 tuberculosis (TB) or have been in close contact with someone who has TB, have or had hepatitis B, have or had liver or kidney problems, are on dialysis, had skin cancer, 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. Do not drink grapefruit juice while on Jakafi.

Women should not take Jakafi while pregnant or planning to become pregnant, or if breast-feeding.

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.