What is the management of essential thrombocythemia (ET)?

From the Guidelines

The management of essential thrombocythemia (ET) should focus on preventing thrombotic complications while minimizing bleeding risk, with treatment risk-stratified based on patient age, prior thrombosis, and platelet count. High-risk patients (age ≥60 years, history of thrombosis, or very high platelet counts) require cytoreductive therapy in addition to aspirin, with first-line cytoreductive options including hydroxyurea or pegylated interferon alfa 1. For younger patients, interferon is often preferred due to its lack of leukemogenic potential 1. The goal of therapy is to normalize platelet counts and prevent complications while maintaining quality of life, as ET is a chronic condition with generally good prognosis but requires lifelong management. Key considerations in management include:

• Risk stratification using the revised International Prognostic Score of Thrombosis for ET (IPSET-Thrombosis) 1
• Use of low-dose aspirin (81-100 mg daily) for vascular symptoms or observation in low-risk patients 1
• Initiation of cytoreductive therapy for symptomatic thrombocytosis, progressive leukocytosis, or disease-related symptoms 1
• Regular monitoring of blood counts, typically every 1-3 months once stable 1
• Consideration of anagrelide or interferon alfa as second-line therapy for patients who are intolerant or resistant to hydroxyurea 1

From the FDA Drug Label

A total of 942 patients with myeloproliferative neoplasms including 551 patients with Essential Thrombocythemia (ET) ... were treated with anagrelide in three clinical trials Patients were enrolled in clinical trials if their platelet count was ≥900,000/μL on two occasions or ≥650,000/μL on two occasions with documentation of symptoms associated with thrombocythemia The dose was increased if the platelet count was still high, but to no more than 12 mg each day. Efficacy was defined as reduction of platelet count to or near physiologic levels (150,000/μL to 400,000/μL).

The management of essential thrombocythemia (ET) involves reducing the platelet count to or near physiologic levels (150,000/μL to 400,000/μL) using medications such as anagrelide. The dose of anagrelide is increased as needed to control the platelet count, up to a maximum of 12 mg per day.

• Key considerations:
  • Platelet count reduction
  • Symptom management
  • Dose adjustment as needed 2

From the Research

Management of Essential Thrombocythemia (ET)

The management of ET involves a risk-oriented approach, taking into account the patient's age, history of thrombosis, and genetic mutations such as JAK2, CALR, and MPL.

• The main goal of therapy is to prevent thrombosis, and low-dose aspirin is recommended for most patients 3, 4, 5, 6, 7.
• Cytoreductive therapy, such as hydroxyurea, is advised for high-risk patients and optional for intermediate-risk patients 3, 4, 5, 6, 7.
• Other therapeutic options, such as interferon alpha or anagrelide, may be used in selected patients, including those who are resistant or intolerant to hydroxyurea 4, 5, 6, 7.
• Strict control of coexistent cardiovascular risk factors is mandatory for all patients 3, 4, 5, 6, 7.

Risk Stratification

Patients with ET can be stratified into different risk categories based on their age, history of thrombosis, and genetic mutations.

• High-risk patients are those older than 60 years or with a history of thrombosis, and they require cytoreductive therapy 3, 4, 5, 6, 7.
• Low-risk patients are those younger than 60 years with no history of thrombosis, and they can be managed with low-dose aspirin alone 3, 4, 5, 6, 7.
• Intermediate-risk patients are those with a history of thrombosis or older than 60 years, but without other high-risk features, and they may require cytoreductive therapy or low-dose aspirin 3, 4, 5, 6, 7.

Special Considerations

Certain situations require special consideration in the management of ET, such as:

• Pregnancy: low-risk women can be given low-dose aspirin throughout pregnancy, while high-risk women may require cytoreductive therapy or low-molecular-weight heparin 4, 5, 6.
• Extreme thrombocytosis: patients with very high platelet counts may require cytoreductive therapy to reduce the risk of thrombosis 5.
• Splanchnic vein thrombosis: patients with this condition may require anticoagulation therapy in addition to cytoreductive therapy 5.