What is anagrelide?

From the Guidelines

Anagrelide is a medication used to treat essential thrombocythemia by reducing platelet production in the bone marrow. It works by inhibiting the maturation of megakaryocytes, the cells responsible for producing platelets. According to the most recent and highest quality study, anagrelide is not inferior to hydroxyurea as first-line therapy for the prevention of thrombotic complications in patients with high-risk essential thrombocythemia 1. The typical dosing of anagrelide starts at 0.5 mg twice daily and is adjusted based on platelet count response, with most patients responding to doses between 1.5-3 mg/day. Some key points to consider when prescribing anagrelide include:

• Common side effects: headache, palpitations, diarrhea, fluid retention, and dizziness
• Regular blood tests are necessary to monitor platelet counts and liver function
• Anagrelide is not suitable for everyone, particularly those with severe heart, liver, or kidney disease, and requires careful medical supervision during treatment
• It is recommended as a second-line therapy for essential thrombocythemia, especially in patients who are intolerant to hydroxyurea 1. In terms of its efficacy and safety, anagrelide has been shown to be effective in reducing platelet counts and preventing thrombotic complications, but it may have a higher risk of arterial thrombosis, serious hemorrhage, and transformation to myelofibrosis compared to hydroxyurea 1. Overall, anagrelide is a valuable treatment option for patients with essential thrombocythemia, but its use should be carefully considered and monitored by a healthcare professional.

From the FDA Drug Label

Anagrelide is a platelet reducing agent indicated for the treatment of thrombocythemia, secondary to myeloproliferative neoplasms, to reduce the elevated platelet count and the risk of thrombosis and to ameliorate associated symptoms including thrombo-hemorrhagic events. Anagrelide is a platelet reducing agent used to treat thrombocythemia secondary to myeloproliferative neoplasms. Its main purpose is to:

• Reduce elevated platelet count
• Decrease the risk of thrombosis
• Ameliorate associated symptoms, including thrombo-hemorrhagic events 2 2

From the Research

Definition and Mechanism of Anagrelide

• Anagrelide is an orally active quinazolin that induces thrombocytopenia in humans, making it a potential treatment for conditions associated with thrombocythaemia 3.
• It has a high specificity towards megakaryocytes, which are responsible for producing platelets, and thus decreases platelet levels 3.
• Anagrelide is also known to have vasodilatory and positive inotropic properties, which can lead to adverse effects such as headache, fluid retention, and palpitations 3, 4.

Therapeutic Uses of Anagrelide

• Anagrelide is used to reduce elevated platelet counts in patients with essential thrombocythaemia and polycythemia vera 5, 6.
• It is particularly useful for patients who are intolerant of or refractory to other treatments, such as hydroxyurea or interferon-alpha 5, 4.
• Anagrelide has been shown to be effective in reducing platelet counts and alleviating symptoms in patients with essential thrombocythaemia, including those who are refractory to other treatments 4.

Efficacy and Safety of Anagrelide

• Studies have shown that anagrelide is effective in reducing platelet counts in patients with essential thrombocythaemia, with response rates ranging from 55% to 93% 3, 4.
• However, anagrelide has been associated with adverse effects such as headache, fluid retention, and palpitations, which can be mild and transient 4.
• Long-term use of anagrelide has been shown to lead to progression of bone marrow fibrosis and hypercellularity in some patients 7.

Comparison with Other Treatments

• Anagrelide has been compared to other treatments, such as hydroxyurea and interferon-alpha, in terms of efficacy and safety 5, 6.
• While anagrelide has been shown to be effective in reducing platelet counts, it may have a higher risk of adverse effects compared to other treatments 5.
• The choice of treatment for essential thrombocythaemia and polycythemia vera ultimately depends on individual patient factors and the specific characteristics of the disease 6.