Long-term efficacy of romiplostim. (A) Change in hematologic parameters during the entire period; (i) platelet count, (ii) hemoglobin concentration, (iii) neutrophil count, and (iv) reticulocyte count. (B) Hematologic responses to romiplostim at (i) 52 weeks, (ii) 104 weeks, and (iii) 156 weeks. The numbers of cases with missing data were 5 at 104 weeks and 21 at 156 weeks. Of the patients for whom data could be collected, no response was 1 at 104 weeks and 0 at 156 weeks.