Table 1.
Baselinea characteristics at romiplostim initiation, overall and stratified by duration of ITP at romiplostim initiation
| Overall (n = 340) |
ITP duration (months) | |||
|---|---|---|---|---|
| < 3 (n = 64) |
3–12 (n = 50) |
> 12 (n = 226) |
||
| Age, median (min, max) | 62 (18, 91) | 67 (19, 88) | 59 (18, 82) | 60 (18, 91) |
| Age at romiplostim initiation (years) | ||||
| 18–64 | 193 (56.8%) | 29 (45.3%) | 29 (58.0%) | 135 (59.7%) |
| 65–74 | 72 (21.2%) | 9 (14.1%) | 11 (22.0%) | 52 (23.0%) |
| 75 + | 75 (22.1%) | 26 (40.6%) | 10 (20.0%) | 39 (17.3%) |
| Male sex | 157 (46.2%) | 30 (46.9%) | 29 (58.0%) | 98 (43.4%) |
| Year of romiplostim initiation | ||||
| 2009 | 65 (19.1%) | 7 (10.9%) | 12 (24.0%) | 46 (20.4%) |
| 2010 | 149 (43.8%) | 32 (50.0%) | 15 (30.0%) | 102 (45.1%) |
| 2011 | 71 (20.9%) | 16 (25.0%) | 11 (22.0%) | 44 (19.5%) |
| 2012 | 55 (16.2%) | 9 (14.1%) | 12 (24.0%) | 34 (15.0%) |
| Weight in kilograms at baseline, median (min, max) | 75 (24, 160) | 79 (45, 130) | 70 (24, 120) | 75 (43, 160) |
| Missing | 4 (1.2%) | 1 (1.6%) | 1 (2.0%) | 2 (0.9%) |
| History of thrombotic events | 35 (10.3%) | 7 (10.9%) | 4 (8.0%) | 24 (10.6%) |
| History of myocardial infarction | 11 (3.2%) | 2 (3.1%) | 1 (2.0%) | 8 (3.5%) |
| History of liver eventb | 17 (5.0%) | 5 (7.8%) | 2 (4.0%) | 10 (4.4%) |
| Baseline platelet count × 109/L, median (min, max) | 20 (0.0, 380) | 17 (0.0, 190) | 19 (1.0, 160) | 21 (1.0, 380) |
| Missing | 3 (0.9%) | 0 (0%) | 0 (0%) | 3 (1.3%) |
| Baseline platelet count | ||||
| 15 | 129 (37.9%) | 30 (46.9%) | 22 (44.0%) | 77 (34.1%) |
| 16–30 | 104 (30.6%) | 22 (34.4%) | 9 (18.0%) | 73 (32.3%) |
| > 30 | 104 (30.6%) | 12 (18.8%) | 19 (38.0%) | 73 (32.3%) |
| Missing | 3 (0.9%) | 0 (0%) | 0 (0%) | 3 (1.3%) |
| Duration of ITP (months), median (min, max) | 40 (0.0, 670) | 0.97 (0.0, 3.0) | 5.8 (3.0, 12) | 81 (12, 670) |
| History of bleedingc | 161 (47.4%) | 48 (75.0%) | 25 (50.0%) | 88 (38.9%) |
| Hospitalized bleeding | 85 (25.0%) | 27 (42.2%) | 14 (28.0%) | 44 (19.5%) |
| Active bleeding | 48 (14.1%) | 16 (25.0%) | 4 (8.0%) | 28 (12.4%) |
| Prior ITP therapies | ||||
| Oral steroid | 253 (74.4%) | 39 (60.9%) | 37 (74.0%) | 177 (78.3%) |
| IV anti-D | 11 (3.2%) | 0 (0%) | 0 (0%) | 11 (4.9%) |
| IVIg | 239 (70.3%) | 45 (70.3%) | 35 (70.0%) | 159 (70.4%) |
| IV steroid | 107 (31.5%) | 31 (48.4%) | 16 (32.0%) | 60 (26.5%) |
| Platelet transfusion | 59 (17.4%) | 23 (35.9%) | 10 (20.0%) | 26 (11.5%) |
| History of splenectomy | 116 (34.1%) | 5 (7.8%) | 4 (8.0%) | 107 (47.3%) |
| AHSCT | 1 (0.3%) | 0 (0%) | 0 (0%) | 1 (0.4%) |
| Azathioprine | 30 (8.8%) | 0 (0%) | 6 (12.0%) | 24 (10.6%) |
| Alemtuzumab | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) |
| Cyclophosphamide | 23 (6.8%) | 0 (0%) | 2 (4.0%) | 21 (9.3%) |
| Cyclosporine | 33 (9.7%) | 0 (0%) | 4 (8.0%) | 29 (12.8%) |
| Danazol | 35 (10.3%) | 1 (1.6%) | 3 (6.0%) | 31 (13.7%) |
| Dapsone | 20 (5.9%) | 0 (0%) | 3 (6.0%) | 17 (7.5%) |
| Mycophenolate | 6 (1.8%) | 0 (0%) | 1 (2.0%) | 5 (2.2%) |
| Rituximab | 130 (38.2%) | 6 (9.4%) | 24 (48.0%) | 100 (44.2%) |
| Vinca alkaloids | 25 (7.4%) | 3 (4.7%) | 3 (6.0%) | 19 (8.4%) |
| Number of ITP treatments received prior to romiplostim initiation, median (min, max) | 3.0 (0.0, 9.0) | 2.0 (0.0, 5.0) | 3.0 (0.0, 6.0) | 3.0 (0.0, 9.0) |
| Number of previous ITP treatments received category | ||||
| 0 | 13 (3.8%) | 2 (3.1%) | 2 (4.0%) | 9 (4.0%) |
| 1 | 62 (18.2%) | 16 (25.0%) | 11 (22.0%) | 35 (15.5%) |
| 2 | 77 (22.6%) | 20 (31.2%) | 9 (18.0%) | 48 (21.2%) |
| 3 + | 188 (55.3%) | 26 (40.6%) | 28 (56.0%) | 134 (59.3%) |
| Number of refractory patientsd | 231 (67.9%) | 29 (45.3%) | 30 (60.0%) | 172 (76.1%) |
ITP immune thrombocytopenia, IV intravenous, AHSCT autologous hematopoietic stem cell transplantation
aMedications were considered to be baseline if the start and end date of the medication happened before the index romiplostim date
bMeasured in the 5 years before romiplostim initiation
cMeasured within 6 months before romiplostim initiation
dPatients were considered to have refractory ITP if they (1) were splenectomized prior to romiplostim initiation, or (2) had three or more ITP therapies prior to romiplostim initiation