The purpose of this research study is to evaluate the safety and effectiveness of patients with Polycythemia Vera treated with Gleevec.

Phlebotomy is a standard temporizing treatment for Polycythemia Vera. Performing repeated phlebotomies may lead to iron deficiency and can contribute to a rising platelet count. This may create additional problems, such as clots particularly in patients older than 50. There is reason to believe that the use of Gleevec may cause a decrease in the activity of the marrow so that patients may not require as many or any phlebotomies. Thus, spleen function may possibly improve by decreasing in size and patients' platelet counts may also improve.

Inclusion Criteria:

• Patients have diagnosis of Polycythemia Vera (PV). Patients may have newly diagnosed PV.

• Patients may have previously interferon-alfa treated PV with documented resistance, refractoriness or intolerance to interferon-alfa.

• Patients may have PV with inadequate control on hydroxyurea.

• Performance status of 0, 1, or 2

• Adequate end organ function, defined as the following:

  1. total bilirubin <1.5 x upper limit of the normal range (ULN)
  2. SGOT (AST) and SGPT (ALT) < 2.5 x ULN
  3. creatinine < 1.5 x ULN
  4. ANC > 1.5 x 109/L

• Written voluntary informed consent.

Exclusion Criteria:

• Female patients who are pregnant or breast-feeding.
• Patients receiving busulfan within 6 weeks of Study Day 1.
• Patients receiving interferon-alpha within 4 weeks of Study Day 1.
• Patients receiving hydroxyurea within 2 weeks of Study Day 1.
• Patients with Grade III or IV cardiac problems as defined by the New York Heart Association Criteria.
• Patients with a history of non-compliance to medical regimens or who are considered potentially unreliable.
• Patients previously treated with Gleevec.
• Serum erythropoietin level > or = 25 units/microliter
• Abnormal O2 saturation (by pulse oximetry) or arterial pO2 (by arterial blood gas).