Clinical Need in PV
Phlebotomy to maintain Hct at <45%
plus low-dose aspirin
Therapeutic approaches to PV focus on3,11:
• Controlling and maintaining hematocrit levels at <45%
• Treating complications of thrombosis and hemorrhage
• Reducing thrombotic risk and minimizing the risk of
leukogenic transformation
• Managing splenomegaly and other disease-related
symptoms
• Poor compliance or tolerance to
frequent phlebotomy
• Symptomatic or progressive splenomegaly
• High risk of thrombosis
• Severe disease-related symptoms
• Progressive myeloproliferation
(leukocytosis or thrombocytosis)
Phlebotomy is usually the starting point of treatment in patients
with PV, in addition to therapy with low-dose aspirin.2,11 Lowdose aspirin has been shown to prevent both arterial and venous
thrombotic complications in patients with PV.18
Hydroxyurea (HU) or interferon-alpha as
first-line cytoreductive therapy at any agea
Cytoreductive therapy with hydroxyurea or interferon-alpha may
also be helpful in patients who have difficulty with phlebotomy,
who have symptomatic or progressive splenomegaly or who
experience severe symptoms.11 Although treatment with
hydroxyurea may be tolerated by most patients, it is important
to consider that approximately 25% of patients with PV develop
resistance to or intolerance of hydroxyurea (Table 1).19, 20
Table 1. Assessment of hydroxyurea (HU) resistance
and intolerance
HU Resistance
After 12 weeks of HU at
a total dose of ≥2 g/day or
at the maximum tolerated
dose, if <2 g/day
• Need for phlebotomy
to maintain Hct level
at <45% or
• Elevated platelet and white
blood cell counts or
• <50% reduction in
splenomegaly
HU Intolerance
At least 1 of the following:
• Neutropenia (absolute
neut ɽ