Essential Thrombocythemia with Arterial Thrombosis History: Next-Line Therapy When Hydroxyurea Has Not Controlled Platelet Count
Clinical Scenario
This protocol addresses patients with essential thrombocythemia who have a history of arterial thrombosis at any age — a high-risk presentation that requires active cytoreductive management to normalise platelet count and reduce the risk of further thrombotic events.
First-Line Therapy & Escalation Trigger
High-risk patients with arterial thrombosis history are initially managed with Hydroxyurea combined with low-dose aspirin. When platelet count cannot be maintained in the normal range on this regimen — the primary therapeutic target — escalation to the next treatment line is indicated.
Next-Line Approach (Partial Overview)
After Hydroxyurea failure or intolerance, an alternative cytoreductive agent is selected, with the choice between available options guided by patient age. The approach draws on pegylated interferon preparations as well as other cytoreductive agents … The complete agent selection, sequencing, and monitoring criteria are detailed in the full protocol.
Treatment Goal
Platelet count maintained in the normal range.
References
DOI: 10.1002/ajh.27216
- Figure 5 outlines our general treatment approach in ET, which starts with thrombosis risk stratification: very low (age ≤60 years, no thrombosis history, JAK2 wild-type), low (same as very low but JAK2 mutation present), intermediate (age >60 years, no thrombosis history, JAK2 wild-type), and high (thrombosis history present or age >60 years with JAK2 mutation).
- We also believe it is reasonable to use twice-daily aspirin in patients with arterial thrombosis if they are older or harbor JAK2 mutations or in the presence of CV risk factors (Figure 5).
- ET patients who are either intolerant or resistant to HU are effectively managed by IFN-α (pegylated preparations preferred) or busulfan.
- Among these 2 s-line drugs, we prefer the use of IFN-α for patients younger than age 65 years and busulfan in the older age group, although there is no controlled evidence to support or refute such a strategy.
- The dose of HU is titrated to keep platelet count in the normal range.
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