<qa>  What is the randomized, open-label, multicenter study?OUTLINE: This is a randomized, open-label, multicenter study. Patients are stratified according to age 61-69 vs 70-75, CD33 positivity less than 5 vs 5-19 vs 20-80 vs more than 80 vs unknown, initial WBC before hydroxyurea administration if needed less than 30,000mm3 vs at least 30,000mm3, and participating center. Patients are randomized to 1 of 2 treatment arms. 