Essential Thrombocythemia with History of Venous Thrombosis — After Hydroxyurea Failure

This protocol addresses high-risk essential thrombocythemia in patients with a prior venous thrombosis at any age, where first-line cytoreductive therapy has not achieved adequate platelet control.

Clinical Situation

A history of venous thrombosis — including events such as deep vein thrombosis — places the patient in the high-risk category for ET. This risk tier requires cytoreductive therapy alongside anticoagulation, with the primary aim of keeping platelet count within the normal range.

First-Line Failure Condition

The previous regimen was hydroxyurea combined with systemic anticoagulation. Despite treatment, the therapeutic target — maintaining platelet count in the normal range — was not reached. This failure of platelet control triggers escalation to the present protocol.

Next-Line Approach (Partial Overview)

When hydroxyurea is not tolerated or fails to achieve platelet control, the strategy shifts to a different cytoreductive agent. The choice of agent is guided by patient age — one pathway involves interferon-alpha therapy. The full selection criteria, treatment sequence, and monitoring parameters are contained in the complete protocol.

Treatment Goal

Maintain platelet count in the normal range.

Instant Access to Structured Evidence-Based Regimens

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).

In patients with venous thrombosis, systemic anticoagulation is advised and the addition of once-daily low-dose aspirin, in the presence of JAK2 mutation or CV risk factors, is reasonable.

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.

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