How it is administered

Ruxolitinib is available in two main forms:

• Oral tablets: These are used for blood cancers and certain immune conditions. The tablets are taken by mouth, usually twice daily, with or without food. Tablet strengths include 5 mg, 10 mg, 15 mg, 20 mg, and 25 mg.

• Topical cream: This form is used for skin conditions like atopic dermatitis and vitiligo, not for blood cancers.

For blood cancers such as myeloproliferative neoplasms, the oral tablet is the standard form. Dosing is individualized based on platelet counts and the specific disease being treated.

How it works

Ruxolitinib is a type of medication known as a Janus kinase (JAK) inhibitor. It works by blocking the activity of two enzymes, JAK1 and JAK2, which are involved in the signaling pathways that control blood cell production and immune responses.

In certain blood cancers, such as myeloproliferative neoplasms (which include myelofibrosis and polycythemia vera), these pathways are overactive, leading to abnormal growth of blood cells. By inhibiting JAK1 and JAK2, ruxolitinib helps to reduce the overproduction of blood cells and decrease inflammation. This can lead to a reduction in symptoms such as enlarged spleen, fatigue, and other disease-related issues. Ruxolitinib also helps regulate immune cell activity, which is important in conditions like graft-versus-host disease.

The effects of ruxolitinib are generally seen within weeks of starting treatment, but it is important to continue taking the medication as prescribed for the best results.

Who Should take it

Ruxolitinib is indicated for adults with certain blood cancers and immune conditions, including:

• Intermediate or high-risk myelofibrosis (including primary myelofibrosis, post-polycythemia vera myelofibrosis, and post-essential thrombocythemia myelofibrosis)
• Polycythemia vera in adults who have had an inadequate response to or are intolerant of hydroxyurea
• Steroid-refractory acute graft-versus-host disease (GVHD) in adults and children 12 years and older
• Chronic graft-versus-host disease after failure of one or two lines of systemic therapy in adults and children 12 years and older

While ruxolitinib is not specifically approved for Chronic Neutrophilic Leukemia (CNL), it may be considered in certain cases under the guidance of a hematologist, especially if other treatments are not effective.

Who should not take it

There are no absolute contraindications listed for ruxolitinib, but certain patients should use caution or avoid it:

• Patients with active, serious infections should not start ruxolitinib until the infection is controlled.
• Patients with severely low blood counts (especially platelets or neutrophils) may need dose adjustments or may not be able to take ruxolitinib safely.
• Ruxolitinib should be used with caution in people with a history of tuberculosis, hepatitis B, or herpes infections, as it can increase the risk of reactivation.
• Pregnant or breastfeeding women should avoid ruxolitinib, as its safety in these populations is not established.

Always discuss your full medical history with your healthcare provider before starting ruxolitinib.

Commonly used with

Ruxolitinib is sometimes used alongside other supportive treatments, such as:

• Blood transfusions (for anemia)
• Antibiotics or antivirals (to prevent or treat infections)
• Other medications to manage symptoms of blood cancers or GVHD

It is important to inform your healthcare provider of all medications you are taking, as ruxolitinib can interact with drugs that affect liver enzymes (especially CYP3A4 inhibitors or inducers).

Commonly tested with

In clinical studies, ruxolitinib has been compared to or used with:

• Hydroxyurea (for polycythemia vera)
• Best available therapy (which may include steroids, immunosuppressants, or other chemotherapy agents for myelofibrosis or GVHD)

It is not typically combined with other JAK inhibitors or strong immunosuppressants due to increased risk of side effects.