Effect of romiplostim on bone marrow in rats
| . | Week 5 (date of death) . | Week 9 (date of death) . | ||||
|---|---|---|---|---|---|---|
| 0 μg/kg romiplostim (n = 20) . | 10 μg/kg romiplostim (n = 18) . | 30 μg/kg romiplostim (n = 20) . | 100 μg/kg romiplostim (n = 17) . | 0 μg/kg romiplostim (n = 10) . | 100 μg/kg romiplostim (n = 10) . | |
| Femur, n (%) | ||||||
| Fibrosis | 0 | 1 (6) | 4 (20) | 9 (53) | 0 | 0 |
| Megakaryocyte hyperplasia | 0 | 9 (50) | 8 (40) | 11 (65) | 0 | 0 |
| Hyperostosis | 0 | 0 | 4 (20) | 12 (71) | 0 | 0 |
| Sternum, n (%) | ||||||
| Fibrosis | 0 | 0 | 1 (5) | 9 (53) | 0 | 0 |
| Megakaryocyte hyperplasia | 0 | 8 (44) | 8 (40) | 10 (59) | 0 | 0 |
| Hyperostosis | 0 | 0 | 0 | 3 (18) | 0 | 0 |
| Mean platelet count, ×109/L | 1077 | 2467 | 1917 | 1981 | 1165 | 1017 |
| . | Week 5 (date of death) . | Week 9 (date of death) . | ||||
|---|---|---|---|---|---|---|
| 0 μg/kg romiplostim (n = 20) . | 10 μg/kg romiplostim (n = 18) . | 30 μg/kg romiplostim (n = 20) . | 100 μg/kg romiplostim (n = 17) . | 0 μg/kg romiplostim (n = 10) . | 100 μg/kg romiplostim (n = 10) . | |
| Femur, n (%) | ||||||
| Fibrosis | 0 | 1 (6) | 4 (20) | 9 (53) | 0 | 0 |
| Megakaryocyte hyperplasia | 0 | 9 (50) | 8 (40) | 11 (65) | 0 | 0 |
| Hyperostosis | 0 | 0 | 4 (20) | 12 (71) | 0 | 0 |
| Sternum, n (%) | ||||||
| Fibrosis | 0 | 0 | 1 (5) | 9 (53) | 0 | 0 |
| Megakaryocyte hyperplasia | 0 | 8 (44) | 8 (40) | 10 (59) | 0 | 0 |
| Hyperostosis | 0 | 0 | 0 | 3 (18) | 0 | 0 |
| Mean platelet count, ×109/L | 1077 | 2467 | 1917 | 1981 | 1165 | 1017 |
Romiplostim or placebo was administered subcutaneously 3 times per week for 4 weeks. Bone marrow samples were taken from animals killed either 3 days after the last dose of romiplostim (week 5) or after a 4-week recovery period (week 9).