Patient selection: primary thrombocythemia following therapy with hydroxyurea
Parameters:
(1) platelet count
(2) white blood cell (WBC) count
(3) hemoglobin
(4) leg ulcers or other unacceptable mucocutaneous lesion related to hydroxyurea therapy
(5) hydroxyurea-related fever
(6) dose and duration of hydroxyurea therapy
(7) body weight
Hydroxyurea resistance or intolerance is defined as one or more of the following:
(1) hydroxyurea-related fever
(2) leg ulcers or other unacceptable mucocutaneous lesion secondary to the hydroxyurea therapy
(3) platelet count > 400,000 per µL AND hemoglobin < 10 g/dL AND any dose of hydroxyurea
(4) platelet count > 400,000 per µL AND WBC count < 2,500 per µL AND any dose of hydroxyurea
(5) platelet count > 600,000 per µL AND > 3 months therapy with hydroxyurea AND
(5a) dose of hydroxyurea >= 2 grams per day if body weight <= 80 kg
(5b) dose of hydroxyurea >= 2.5 g per day if body weight > 80 kg
where:
• The duration of hydroxyurea therapy for criteria 3 and 4 are not specified.
