Baseline, maximal, and median platelet counts for maintained responders, nonmaintained responders, nonresponders, and all patients in study. Maintained response is defined as platelet count increased by at least 20 × 109/L (20 000/mm3) to greater than 30 × 109/L (30 000/mm3) on at least 66% of the study visits. Nonmaintained response is defined as platelet counts increased by at least 20 × 109/L (20 000/mm3) to greater than 30 × 109/L (30 000/mm3) on less than 66% of the study visits. Nonresponders did not achieve any increases in platelet counts as per the above definition. Baseline platelet counts represent the lowest count within 1 month of study start. Maximum and average platelet counts were calculated as the median of peak and average counts, respectively, achieved by each patient in a given group.