Jakafi

Bone Marrow Disorders

Jakafi is used to treat certain types of myelofibrosis, a condition where scar tissue replaces bone marrow. This includes primary myelofibrosis and myelofibrosis that occurs after other blood disorders, such as polycythemia vera or essential thrombocythemia. It is typically prescribed for patients with intermediate or high-risk forms of these conditions.

It is also used to treat polycythemia vera, a condition where the body produces too many red blood cells. In this case, Jakafi is used for adults who have had an inadequate response to or cannot tolerate hydroxyurea.

Graft-Versus-Host Disease

This medication is also prescribed for graft-versus-host disease (GVHD), a complication that can occur after a stem cell or bone marrow transplant when the donor cells attack the recipient's body. It is used in the following situations:

• Acute GVHD: For adults and children 12 years of age and older who have steroid-refractory acute graft-versus-host disease.
• Chronic GVHD: For adults and children 12 years of age and older who have chronic graft-versus-host disease after failing one or two previous systemic treatments.

Mechanism of Action

Jakafi belongs to a class of medications known as kinase inhibitors. It works by blocking the activity of enzymes called Janus Associated Kinases, specifically JAK1 and JAK2. These enzymes play a critical role in the signaling pathways that tell the body how to produce blood cells and how the immune system should respond to various triggers.

Managing Blood Disorders

In certain blood and bone marrow disorders, such as myelofibrosis and polycythemia vera, the JAK signaling pathway becomes overactive. This overactivity causes the body to produce too many blood cells and leads to significant inflammation. By inhibiting JAK1 and JAK2, Jakafi helps to:

• Slow down the excessive production of blood cells.
• Reduce inflammation throughout the body.
• Shrink an enlarged spleen, which is a common symptom of these conditions.

Role in Graft-Versus-Host Disease

For patients with graft-versus-host disease (GVHD), Jakafi works by interfering with the signals that cause transplanted immune cells to attack the patient's own tissues. By blocking these pathways, the medication helps dampen the immune response and reduce the damage caused by the condition.

Common Side Effects

Common side effects of Jakafi may include:

• Bruising
• Dizziness
• Headache
• Diarrhea
• Tiredness or fatigue
• Shortness of breath
• Weight gain
• Constipation or gas

Serious Side Effects

Jakafi can cause serious side effects. Seek medical help if you notice:

• Low blood cell counts: Decreased levels of red blood cells, white blood cells, or platelets. This may cause unusual bleeding, bruising, or extreme tiredness.
• Infections: Increased risk of developing serious bacterial, fungal, or viral infections, including shingles (herpes zoster).
• Skin cancer: Some people have developed certain types of non-melanoma skin cancers. Check your skin for any new or changing growths.
• Changes in lab results: Increased cholesterol levels or signs of liver damage, such as yellowing of the eyes or skin.

Serious Heart-Related Events and Cancer

Based on studies of medications in the same drug class, there is an increased risk of major cardiovascular events, including heart attack and stroke, as well as certain types of cancer, such as lymphoma and lung cancer. These risks may be higher in individuals who are current or former smokers.

Blood Clots

There is an increased risk of blood clots in the veins of the legs (deep vein thrombosis) or the lungs (pulmonary embolism). These conditions can be serious or fatal. Medical attention is necessary if symptoms like leg swelling, chest pain, or shortness of breath occur.

Infections

Jakafi can weaken the immune system, increasing the risk of serious bacterial, mycobacterial, fungal, and viral infections. This includes the reactivation of shingles (herpes zoster) or hepatitis B. Healthcare providers typically check for tuberculosis (TB) before starting treatment and monitor for signs of infection throughout therapy.

Low Blood Counts

Treatment often leads to a decrease in blood cell counts, including:

• Thrombocytopenia: Low platelet counts, which can increase the risk of bleeding.
• Anemia: Low red blood cell counts, which may require blood transfusions.
• Neutropenia: Low white blood cell counts, which can make it harder to fight infections.

Frequent blood tests are required to monitor these levels, and dosages may be adjusted based on the results.

Non-Melanoma Skin Cancer

Some patients taking Jakafi have developed non-melanoma skin cancers, such as basal cell or squamous cell carcinoma. Regular skin examinations are recommended during treatment.

Cholesterol Elevations

Increases in cholesterol and triglyceride levels have been observed in patients taking this medication. Monitoring of lipid levels is usually performed during treatment.

Discontinuation Symptoms

Stopping Jakafi abruptly can cause symptoms of the underlying condition to return or worsen rapidly. It is important not to change the dose or stop the medication without medical guidance.

Pregnancy

There is limited research on the use of Jakafi in pregnant individuals. In animal studies, the medication was associated with an increased risk of pregnancy loss and lower birth weights in offspring. Because of these potential risks, healthcare providers typically only prescribe Jakafi during pregnancy if the benefits to the patient outweigh the risks to the fetus.

If you are pregnant or planning to become pregnant, it is important to discuss your treatment options with your doctor. Individuals who can become pregnant may be advised to use effective contraception during treatment.

Breastfeeding

It is currently unknown whether Jakafi passes into human breast milk. Due to the potential for serious adverse reactions in a nursing infant, breastfeeding is not recommended while taking this medication. Most guidelines suggest waiting at least two weeks after the final dose of Jakafi before breastfeeding.

Dosage Forms

Jakafi is available as a tablet for oral administration.

• Oral tablet

FDA Approval and Indications

Jakafi was first approved by the U.S. Food and Drug Administration (FDA) in 2011. It is currently indicated for the treatment of:

• Intermediate or high-risk myelofibrosis, including primary myelofibrosis and myelofibrosis that follows other blood conditions.
• Polycythemia vera in adults who have had an inadequate response to or cannot tolerate hydroxyurea.
• Steroid-refractory acute graft-versus-host disease (GVHD) in adult and pediatric patients 12 years and older.
• Chronic graft-versus-host disease in adult and pediatric patients 12 years and older after the failure of one or two previous systemic treatments.

Regulatory Safety Status

In 2021, the FDA issued a safety communication requiring new and updated warnings for certain Janus kinase (JAK) inhibitors regarding increased risks of serious heart-related events, cancer, blood clots, and death. However, the FDA explicitly stated that Jakafi was not included in this specific safety communication because it is not indicated for the treatment of inflammatory conditions like rheumatoid arthritis.

While Jakafi does not carry the same boxed warnings as some other JAK inhibitors, the FDA-approved labeling requires healthcare providers to monitor patients for other serious risks, including:

• Serious bacterial, mycobacterial, fungal, and viral infections.
• Changes in blood counts, such as anemia, thrombocytopenia, and neutropenia.
• Non-melanoma skin cancers.
• Increased lipid levels (cholesterol).

There is currently no Risk Evaluation and Mitigation Strategy (REMS) required for the distribution or use of Jakafi.

Factors Affecting Cost

The cost of Jakafi can vary based on several factors, including the specific condition being treated, the prescribed dosage, and the pharmacy used. Because it is a specialized treatment, it is typically more expensive than common medications.

Insurance and Prior Authorization

Most private insurance plans and Medicare Part D cover Jakafi, but they often require prior authorization. This process involves your healthcare provider submitting documentation to the insurance company to confirm the medication is medically necessary before coverage is approved. Your out-of-pocket costs, such as copays or coinsurance, will depend on your specific plan's formulary and deductible status.

Generic Availability

There is currently no generic version of Jakafi (ruxolitinib) available. Brand-name medications without generic alternatives generally have higher costs until patent protections expire and generic manufacturers can enter the market.

Financial Assistance Programs

The manufacturer of Jakafi offers support programs to help patients manage the cost of the drug. These may include:

• Copay Cards: These can reduce out-of-pocket expenses for patients with commercial (private) insurance.
• Patient Assistance Programs: These programs may provide the medication at no cost or a reduced cost for individuals who are uninsured or underinsured and meet specific income requirements.

Specialty Pharmacies

Jakafi is usually distributed through specialty pharmacies rather than standard retail pharmacies. These pharmacies are equipped to handle high-cost medications that require special handling, monitoring, or patient support services. Your insurance provider or doctor can help identify which specialty pharmacy you must use.