Jakafi (ruxolitinib) is a prescription medicine for people with certain types of polycythemia vera (PV). It is not chemotherapy. In 2014, it was approved for people with PV who did not respond well to or could not tolerate hydroxyurea. Jakafi is a pill swallowed twice daily.
How Does Jakafi Work?
PV is a type of blood cancer. These conditions are caused when certain signals from proteins called JAKs don’t work properly. This can lead to inflammation, abnormal growth of blood cells, tissue damage, and other issues. Jakafi helps reduce these problems by blocking JAKs.
Is Jakafi Right for Me?
Jakafi may be the right choice for you if you are an adult with PV who tried a medicine called hydroxyurea, but it did not work well or caused problems.
Your health care provider will examine you, review your medical history, and look at your lab results to decide if Jakafi is right for you.
How Was Jakafi Studied for PV?
One study, the RESPONSE trial, was done to see how well Jakafi worked in people with PV compared with other medicines.
The main question in this study was how well Jakafi could control hematocrit (the amount of whole blood that is made up of red blood cells) and reduce the spleen size. To find out, the researchers looked at how many people had a decrease of at least 35% in their spleen size after about eight months (32 weeks) of taking Jakafi compared to when the study started. They measured the spleen size using MRI or CT scans.
The researchers also looked at how many people kept their reduced spleen size about one year (48 weeks) after the study began and how many had controlled blood cell levels about eight months (32 weeks) after the study started.
What medicines did the people in the study take?
People in the study either took Jakafi or other medicines for PV as prescribed by the study doctor for each person.
Who was included in the study?
People in the study met the following requirements:
- Aged 18 years or older
- PV for at least 6 months before the beginning of the study
- Did not respond well enough to hydroxyurea or could not take it
- Needs phlebotomy (drawing blood to remove extra red blood cells)
- Enlarged spleen
Who was excluded from the study?
People could not be in this study if they had:
- Low liver or kidney function
- Serious infections that require medicine
- Cancer within the past five years (except for certain skin cancers)
- Hepatitis or HIV
- Previously taken experimental medicines
What was the study population?
- A total of 110 people in the study took Jakafi and 112 took other medicines.
- The average age of these people was 60 (from a range of 33 to 90). About one-third were older than 65.
- About 66% of them were male and 34% were female.
- Of the people who took other medicines, 60% took hydroxyurea, 12% got interferon/pegylated, 7% took anagrelide, 2% got pipobroman, and 5% took lenalidomide/thalidomide. About 15% were not given any medication.
- A total of 194 people were White (87%),1 was Black (less than 1%), and 27 were Asian (12%).
How long was the study?
People who took Jakafi were in the study for about 1.5 years (80 weeks).
What Were the Main Benefits of Jakafi in People With PV Seen in the Study?
- Significantly more people taking Jakafi showed a response (a reduction in spleen size and controlled blood cell levels) after about eight months (32 weeks) compared to those who took other medicines. Most of these people kept their response about one year (48 weeks) after the study began.
Significantly more people who took Jakafi had complete control of blood cell levels around eight months (32 weeks) into the study compared to those on other medicines.
Jakafi
Other medicines
People who showed a response after eight months
23%
Less than 1%
People who kept the response after one year
20%
Less than 1%
People who showed a complete control of blood cell levels after eight months
24%
8%
What Are the Side Effects of Jakafi, and How Can I Prevent or Manage Them?
Jakafi may cause serious side effects such as:
Low blood cell count
Jakafi may cause low blood platelets (thrombocytopenia), low red blood cells (anemia), or low white blood cells (neutropenia). Your doctor will order regular blood tests and adjust the dose for Jakafi or tell you to stop taking it if needed.
Let your doctor know right away if you have unusual bleeding or bruises or if you feel very tired or short of breath.
Higher risk of infections
- Let your health care provider know if you have signs of an infection, such as fever, chills, runny nose, nausea, vomiting, feeling very tired, a cough that won’t go away, or painful skin rash or blisters. Be sure to drink plenty of fluids and get enough rest.
Your pharmacist might suggest over-the-counter medicines for fever or pain, like acetaminophen or ibuprofen, or cough medicine. Try to avoid being around sick people and stay away from crowded places, especially during cold and flu season. For added protection, wear a well-fitting mask in busy areas.
- Shingles: Let your doctor know if you have signs of shingles such as pain, itching, or tingling especially on one side of your face or body.
- Brain infections: Jakafi may rarely cause a type of brain infection called progressive multifocal leukoencephalopathy. Let your doctor know if you feel clumsy or weak or have trouble speaking or seeing.
Skin cancer
Jakafi may increase the risk of certain types of skin cancers. Let your doctor know if you have had skin cancer in the past or if you notice any new or changing skin spots or lumps that don’t go away.
Higher blood cholesterol levels
Your doctor will regularly check your cholesterol levels. They may also recommend adding more fruits and vegetables, fish, and nuts to your diet.
Serious heart problems (like heart attacks or strokes)
If you smoke, try to quit or cut back.
Call for emergency help right away if you feel very weak or tired, have trouble breathing, feel pain or tightness in your chest, have nausea and vomiting, break out in a cold sweat, feel lightheaded, or have trouble speaking.
Blood clots
Other medicines similar to Jakafi have caused blood clots in the legs (deep vein thrombosis) or lungs (pulmonary embolism).
- Symptoms of a blood clot in the leg include pain, swelling, warmth, and redness.
- Symptoms of a blood clot in the lung include shortness of breath, sudden chest pain, coughing up blood, and feeling faint or lightheaded.
Inform your doctor right away if you notice any of these symptoms.
These are not all the possible side effects of Jakafi. Contact your health care provider for medical advice about side effects if you are having symptoms that bother you. You can report side effects to the FDA at 800-FDA-1088 or www.fda.gov/medwatch. You can also report side effects to the manufacturer, Incyte Corporation, at 855-463-3463.
How Do I Know if Jakafi Is Working?
You might notice that your symptoms are improving. Your doctor may also use the Lee Symptom Scale to track changes in your symptoms. In addition, they will check how well Jakafi is working by ordering regular lab tests to look at your blood cell counts. They may also do imaging tests like MRI and CT scans to check the size of your spleen.
Do not stop taking Jakafi or change how you take it without your doctor’s advice, as this could make your symptoms come back.
How Do Foods and Other Medicines Interact With Jakafi ?
Tell your health care providers and pharmacist about all the other prescription and nonprescription medicines, vitamins, supplements, and herbal products you take before starting Jakafi. Some medicines and foods may interfere with how Jakafi works in your body. This is because they can interfere with one of the proteins that help break down Jakafi before it leaves your body, called CYP3A4.
Medicines or foods that can stop CYP3A4 from working are called CYP3A4 inhibitors, while those that can make it more active are called CYP3A4 inducers.
CYP3A4 inhibitors make Jakafi linger in your body longer than it should, causing more side effects. Some medicines in this group are certain antifungals (like fluconazole and ketoconazole), certain antibiotics (like clarithromycin and erythromycin), and certain antiretrovirals (like ritonavir). Grapefruit and grapefruit juice are also in this group.
CYP3A4 inducers cause Jakafi to leave your body quicker, making it less effective. Some examples of these medicines are certain antibiotics (like rifampicin), and certain anti-seizure medicines (like carbamazepine and phenytoin). Natural medicines like St. John’s wort are also in this group.
Your health care provider will decide if you need to stop taking a medicine or avoid certain foods while you are taking Jakafi or if you need to adjust the dose of these medicines. Your pharmacist can tell you which foods or medicines interact with Jakafi.
How Can I Get Jakafi?
You will need a prescription from a doctor who specializes in blood and bone marrow cancer treatment. Your doctor will arrange for you to get Jakafi from a specialty pharmacy.
If you need help paying for Jakafi, the manufacturer may be able to assist you. Check out their IncyteCARES Support Program to learn more about getting help with costs and your insurance coverage. You can also contact the manufacturer at 855-452-5234.
