What to Know About Jakafi (Ruxolitinib)

Jakafi (ruxolitinib) is a type of drug called a Janus kinase (JAK) inhibitor that is used to treat blood cancers known as polycythemia vera (PV) and myelofibrosis. Both are myeloproliferative neoplasms that cause bone marrow to make too many blood cells.

Jafafi is also used to treat a complication of a stem cell or bone marrow transplant known as graft-versus-host disease (GVHD). GVHD occurs when white blood cells produced by donated stem cells or bone marrow attack your body's own cells.

Jakafi works by blocking the production of compounds called growth factors that stimulate blood cell production in the bone marrow. By doing so, the drug can bring these bone marrow-related conditions under control.

The articles describe the uses of Jafaki, including how the drug is prescribed and taken. It also lists the possible risks, side effects, and drug interactions.

What Is Jakafi Used For?

First licensed for use by the Food and Drug Administration (FDA) in 2011, Jakafi is approved for the treatment of:

• Myelofibrosis: This is a type of blood cancer that causes scarring (fibrosis) of the bone marrow, leading to low blood counts, abnormal bleeding, liver problems, and acute leukemia. Jakafi is only used in adults with myelofibrosis.
• Polycythemia vera: This is a type of blood cancer that causes your body to make too many red blood cells, leading to blood clots, splenomegaly (enlarged spleen), and organ damage, Jakafi is used in adults with PV when first-line treatments fail or cause intolerable side effects.
• Acute graft-versus-host disease: This is a form of GVHD that develops within 100 days of a transplant, typically affecting the skin, liver, and digestive tract. Jakafi is used in adults and children 12 and over when corticosteroid (steroid) drugs fail.
• Chronic graft-versus-host disease: This is a form of a form of GVHD that occurs 100 days or more after a transplant, affecting the skin, liver, digestive tract. and many other organs. Jakafi can be used in adults and children 12 and over.

Myelofibrosis can occur on its own (primary myelofibrosis) but can also be the result of injury to the bone marrow caused by PV (post-polycythemia vera myelofibrosis).

How Is Jakafi Used?

Jakafi is available as a tablet in a 5-milligram (mg), 10-mg, 15-mg, 20-mg, and 25-mg dose. The drug is taken twice daily by mouth with or without food. The dose varies based on the condition being treated and other factors, like your blood count.

Jakufi is given at a lower starting dose that is gradually increased until the desired effect is achieved. This allows the healthcare provider to monitor for potentially serious side effects.

During treatment, your healthcare will monitor your blood counts to ensure they remain within the normal range. If they don't, the dose may need to be reduced or the drug temporarily stopped and restarted.

Because Jakafi drug can cause liver toxicity, the dose may need to be reduced for people with pre-existing liver disease.

Jakafi is stored at room temperature (68 F to 77 F) but can be kept at temperatures between 59 F and 86 F for short excursions. Keep the drug in its original, light-resistant container, and do not store it in your glove compartment or on a sunny windowsill. Discard any drug that has expired.

Possible Side Effects of Jakafi

There are no contraindications to Jakafi. Because PV, myelofibrosis, and GVHD are serious and potentially life-threatening, the benefits of treatment generally outweigh the risks.

With that said, Jakafi does carry a significant risk of side effects. most commonly due to steep drops in red blood cells (anemia), platelets (thrombocytopenia), and white blood cells known as neutrophils (neutropenia).

Common side effects of Jakafi include:

• Easy bruising
• Dizziness
• Headache
• Diarrhea
• Urinary tract infections (UTI)
• Weight gain
• Gas

Because Zakafi works by suppressing parts of your immune system, it can increase your risk of certain serious infections and diseases, including:

• Tuberculosis, progressive multifocal leukoencephalopathy (PML), herpes zoster (shingles), and hepatitis B
• Heart attack and stroke
• Non-melanoma skin cancer
• Deep venous thrombosis (DVT) and pulmonary embolism (PE)

Possible Drug Interactions

There are many possible drug interactions with Zakafi. This is because the drug relies on a liver enzyme called cytochrome P3A4 (CYP3A4) for metabolization (the process of breaking substances so that they can be distributed throughout the body).

Because other drugs rely on CYP3A4 for metabolization, there may be competition for the available enzyme. In some cases, this can cause concentrations of Zafaki to drop due to the lack of CYP3A4, making the drug less effective.

Possible drug interactions include:

• Antibiotics like clarithromycin, erythromycin, and Rifaden (rifampin)
• Anticonvulsants like Tegretol (carbamazepine) and Dilantin (phenytoin)
• Antifungals like Diflucan (fluconazole) and Sporanox (itraconazole
  
• Calcium channel blockers like Cardizem (diltiazem) and Verelan (verapamil)
• Corticorticosteroid drugs like dexamethasone
• Selective serotonin reuptake inhibitor (SSRI) antidepressants like Prozac (fluoxetine)

Advise your healthcare of any drugs you take whether they are prescription, over-the-counter, nutritional, herbal, or recreational.

Based on the severity of the interaction, the dose of the competing drug may need to be separated by several hours or the dosage adjusted. In some cases, a drug substitution may be needed.

Summary

Jakafi (ruxolitinib) is a prescription drug approved to treat serious bone marrow-related disorders like myelofibrosis, polycythemia vera, and graft-versus-host disease. It works by altering the immune response and normalizing the production of blood cells from the bone marrow.

Jakafi is taken by mouth twice daily. The dose varies by the disease being treated. Side effects include easy bruising, dizziness, headache, diarrhea, and an increased risk of infection, heart disease, stroke, blood clots, and certain types of skin cancer.

Jakafi can interact with many drugs so advise your healthcare provider about any drugs you take prior to starting treatment.