Common brand names

• Ayvakit

How it is administered

Avapritinib is taken by mouth as a film-coated tablet. It is available in several strengths: 25 mg, 50 mg, 100 mg, 200 mg, and 300 mg. The tablets should be taken on an empty stomach, at least 1 hour before or 2 hours after a meal. The recommended dose for advanced systemic mastocytosis (AdvSM) is 200 mg once daily, and for indolent systemic mastocytosis (ISM) it is 25 mg once daily. Your healthcare provider will determine the right dose for you and may adjust it based on your response and any side effects.

How it works

Avapritinib is a type of medicine called a tyrosine kinase inhibitor. It works by blocking abnormal proteins in the body, specifically those made by mutated forms of the KIT and PDGFRA genes. These abnormal proteins can cause certain blood cancers, including systemic mastocytosis, to grow and spread.

By blocking these proteins, avapritinib helps to slow down or stop the growth of the abnormal mast cells that are responsible for the symptoms and complications of systemic mastocytosis. This can help reduce symptoms, improve blood counts, and decrease the burden of disease in the bone marrow and other organs. Avapritinib is especially effective in patients whose disease is driven by the KIT D816V mutation, which is common in systemic mastocytosis.

Who should take it

Avapritinib is approved for adults with advanced systemic mastocytosis (AdvSM), which includes aggressive systemic mastocytosis, systemic mastocytosis with an associated hematological neoplasm (SM-AHN), and mast cell leukemia (MCL). It is also approved for adults with indolent systemic mastocytosis (ISM) who have moderate to severe symptoms despite other treatments.

Your doctor may recommend avapritinib if you have been diagnosed with one of these forms of systemic mastocytosis, especially if you have the KIT D816V mutation. It is also used in certain cases of gastrointestinal stromal tumors (GIST) with specific mutations. Your healthcare provider will decide if avapritinib is right for you based on your diagnosis and overall health.

Who should not take it

Avapritinib should not be used in patients with platelet counts less than 50 × 10^9/L, as it may increase the risk of serious bleeding. It is not recommended for use in children, as its safety and effectiveness have not been established in pediatric patients.

If you are pregnant or planning to become pregnant, you should not take avapritinib, as it can cause harm to an unborn baby. Women who are breastfeeding should also avoid this medication. Always tell your doctor about all your medical conditions and medications before starting avapritinib.

Commonly used with

For indolent systemic mastocytosis, avapritinib is often used together with best supportive care, which may include antihistamines (H1 and H2 blockers), leukotriene inhibitors, and cromolyn sodium to help manage symptoms.

It is important to inform your healthcare provider about all other medications you are taking, as avapritinib can interact with other drugs.

Commonly tested with

Avapritinib has been studied in combination with best supportive care for systemic mastocytosis. In clinical trials, patients often continued their symptom-directed therapies, such as antihistamines and leukotriene inhibitors, while taking avapritinib.

It is not typically combined with other cancer therapies, but your doctor may recommend supportive medications to help manage side effects.