From the Guidelines
Tempi (Imetelstat) is not currently recommended for the treatment of thrombocytosis, and instead, hydroxyurea, anagrelide, or interferon-alpha should be considered as first-line treatments. For patients with thrombocytosis, especially in the context of myeloproliferative neoplasms like essential thrombocythemia, the first-line treatment is typically hydroxyurea at a starting dose of 500-1000 mg daily, adjusted to maintain platelet counts below 400,000/μL, as recommended by the European LeukemiaNet 1. Alternatively, anagrelide (starting at 0.5 mg twice daily) or interferon-alpha can be used, particularly in younger patients or those who cannot tolerate hydroxyurea.
Key Considerations
- Low-dose aspirin (81-100 mg daily) is also commonly added to reduce thrombotic risk, as supported by the American College of Chest Physicians evidence-based clinical practice guidelines 1.
- Imetelstat, a telomerase inhibitor, has shown promise in clinical trials for myelofibrosis and essential thrombocythemia but remains investigational for thrombocytosis.
- The choice of therapy should be based on the underlying cause of thrombocytosis, the patient's risk factors for thrombotic events, age, and comorbidities, as outlined in the National Stroke Association guidelines for the management of transient ischemic attacks 1.
- Treatment is generally indicated when platelet counts exceed 1,000/μL or in patients with additional cardiovascular risk factors.
Treatment Goals
- The goal of therapy is to reduce the risk of thrombotic and hemorrhagic complications by controlling platelet counts while minimizing treatment-related side effects.
- The management of thrombocytosis should prioritize the reduction of morbidity, mortality, and improvement of quality of life, as emphasized by the European LeukemiaNet 1.
From the Research
Tempi and Thrombocytosis
- Thrombocytosis is a condition characterized by an elevated platelet count, typically above 450 × 10^9/L 2, 3, 4.
- Essential thrombocythemia is a type of myeloproliferative neoplasm that is often associated with thrombocytosis, and is characterized by a clonal proliferation of megakaryocytes 2, 3.
- The diagnosis of essential thrombocythemia requires the exclusion of other myeloid neoplasms, and is often based on the presence of a JAK2 mutation, as well as other genetic markers such as CALR and MPL 2, 3.
Causes of Thrombocytosis
- Thrombocytosis can be primary, meaning it is caused by a clonal disorder such as essential thrombocythemia, or secondary, meaning it is caused by a reactive process such as tissue injury or infection 4, 5.
- The most common causes of secondary thrombocytosis include tissue injury, infection, chronic inflammatory disorders, and iron deficiency anemia 4.
- Primary thrombocytosis is often associated with an increased risk of thrombosis, and requires careful management to prevent this complication 2, 3, 5.
Management of Thrombocytosis
- The management of thrombocytosis depends on the underlying cause, as well as the individual patient's risk factors for thrombosis 2, 3, 5.
- Low-dose aspirin is often recommended for patients with essential thrombocythemia, as it can help to reduce the risk of thrombosis 2, 3.
- Cytoreductive therapy, such as hydroxyurea, may also be recommended for patients with high-risk essential thrombocythemia, as it can help to reduce the risk of thrombosis by lowering the platelet count 2, 3.