How it is administered

Ruxolitinib is taken by mouth as a tablet. The tablets are available in different strengths (5 mg, 10 mg, 15 mg, 20 mg, and 25 mg). The medication can be taken with or without food. If you are unable to swallow tablets, ruxolitinib can also be given through a nasogastric tube by suspending the tablet in water.

The starting dose for myelofibrosis depends on your platelet count:

• Platelet count greater than 200 x 10⁹/L: 20 mg twice daily
• Platelet count 100–200 x 10⁹/L: 15 mg twice daily
• Platelet count 50–100 x 10⁹/L: 5 mg twice daily

How it works

Ruxolitinib is a type of medicine called a kinase inhibitor. It works by blocking certain enzymes in your body known as Janus Associated Kinases (JAK1 and JAK2). These enzymes are important for the signaling of substances (cytokines and growth factors) that help control the growth and function of blood cells and the immune system.

In myelofibrosis, the JAK pathway is often overactive, leading to abnormal blood cell growth and symptoms like an enlarged spleen and fatigue. By blocking JAK1 and JAK2, ruxolitinib helps to reduce the abnormal signaling, which can decrease spleen size, lower the number of abnormal cells, and improve symptoms such as night sweats, bone pain, and itching. It also helps to reduce the levels of inflammatory substances in the body, which can contribute to feeling better overall.

Ruxolitinib is not a cure for myelofibrosis, but it can help manage the disease and improve quality of life.

Who Should take it

Ruxolitinib is approved for adults with intermediate or high-risk myelofibrosis, including:

• Primary myelofibrosis
• Post-polycythemia vera myelofibrosis
• Post-essential thrombocythemia myelofibrosis

It is also used in adults with polycythemia vera who have not responded to or cannot tolerate hydroxyurea. Your doctor will determine if ruxolitinib is right for you based on your disease risk, symptoms, and blood counts. Ruxolitinib may help reduce spleen size, improve symptoms, and enhance quality of life for people with myelofibrosis.

Who should not take it

There are no absolute contraindications listed for ruxolitinib, but it should not be started if you have an active, serious infection. Caution is needed if you have very low blood counts (especially platelets or neutrophils), as ruxolitinib can further lower these counts. Your doctor will monitor your blood counts closely and may adjust your dose or pause treatment if necessary.

If you have a history of tuberculosis, hepatitis B, or certain viral infections, let your doctor know before starting ruxolitinib. Women who are pregnant or breastfeeding should not use ruxolitinib, as it may harm the baby.

Commonly used with

Ruxolitinib is often used alone for myelofibrosis. In some cases, it may be used alongside blood transfusions if you develop anemia, or with other supportive treatments to manage symptoms or side effects. It is not typically combined with other chemotherapy drugs for myelofibrosis.

Commonly tested with

In clinical studies, ruxolitinib has been compared to placebo or best available therapy, which may include hydroxyurea, corticosteroids, or other supportive treatments. It has also been studied in combination with other medications in research settings, but for myelofibrosis, it is most commonly tested as a single agent.