Characteristics of pediatric patients with ITP with postbaseline anti-romiplostim binding antibody results in clinical trials
| Characteristic . | Developed postbaseline anti-romiplostim binding antibodies . | |||
|---|---|---|---|---|
| Yes (n = 25) . | No (n = 259) . | |||
| n (%) or median . | (95% CI) or [Q1, Q3] . | n (%) or median . | (95% CI) or [Q1, Q3] . | |
| Female | 14 (56.0) | (34.9, 75.6) | 128 (49.4) | (43.2, 55.7) |
| Age, y | 10.0 | [6.0, 14.0] | 10.0 | [6.0, 13.0] |
| Race, White | 19 (76.0) | (54.9, 90.6) | 196 (75.7) | (70.0, 80.8) |
| Baseline platelet count (×109/L), median | 18.0 | [14.3, 22.0] | 14.0 | [7.5, 23.7] |
| ITP duration (>3 y)* | 9 (36.0) | (18.0, 57.5) | 93 (35.9) | (30.1, 42.1) |
| Prior splenectomy | 3 (12.0) | (2.5, 31.2) | 17 (6.6) | (3.9, 10.3) |
| Baseline anti-romiplostim binding antibodies | 0 (0) | (0.0, 13.7) | 2 (0.8) | (0.1, 2.8) |
| Baseline anti-romiplostim neutralizing antibodies | 0 (0) | (0.0, 13.7) | 0 (0) | (0, 1.4) |
| Previous ITP treatments, median n | 2.0 | [2.0, 3.0] | 2.0 | [2.0, 3.0] |
| Prior rituximab use | 5 (20.0) | (6.8, 40.7) | 54 (20.8) | (16.1, 26.3) |
| Prior corticosteroid use | 23 (92.0) | (74.0, 99.0) | 225 (86.9) | (82.1, 90.7) |
| Medical history | ||||
| Abdominal pain | 0 (0) | (0, 13.7) | 12 (4.6) | (2.4, 8.0) |
| Allergies | 4 (16.0) | (4.5, 36.1) | 31 (12.0) | (8.3, 16.6) |
| Autoimmune neutropenia | 0 (0) | (0, 13.7) | 0 (0) | (0, 1.4) |
| Autoimmune thyroiditis | 0 (0) | (0, 13.7) | 1 (0.4) | (0, 2.1) |
| Chest pain | 0 (0) | (0, 13.7) | 0 (0) | (0, 1.4) |
| Immunodeficiency | 0 (0) | (0, 13.7) | 3 (1.2) | (0.2, 3.3) |
| Kidney disorder | 1 (4.0) | (0.1, 20.4) | 2 (0.8) | (0.1, 2.8) |
| Liver disorder | 0 (0) | (0, 13.7) | 1 (0.4) | (0, 2.1) |
| Musculoskeletal pain | 1 (4.0) | (0.1, 20.4) | 12 (4.6) | (2.4, 8.0) |
| Oropharyngeal pain | 0 (0) | (0, 13.7) | 4 (1.5) | (0.4, 3.9) |
| Pain | 0 (0) | (0, 13.7) | 3 (1.2) | (0.2, 3.3) |
| Thyroid disease | 1 (4.0) | (0.1, 20.4) | 2 (0.8) | (0.1, 2.8) |
| Characteristic . | Developed postbaseline anti-romiplostim binding antibodies . | |||
|---|---|---|---|---|
| Yes (n = 25) . | No (n = 259) . | |||
| n (%) or median . | (95% CI) or [Q1, Q3] . | n (%) or median . | (95% CI) or [Q1, Q3] . | |
| Female | 14 (56.0) | (34.9, 75.6) | 128 (49.4) | (43.2, 55.7) |
| Age, y | 10.0 | [6.0, 14.0] | 10.0 | [6.0, 13.0] |
| Race, White | 19 (76.0) | (54.9, 90.6) | 196 (75.7) | (70.0, 80.8) |
| Baseline platelet count (×109/L), median | 18.0 | [14.3, 22.0] | 14.0 | [7.5, 23.7] |
| ITP duration (>3 y)* | 9 (36.0) | (18.0, 57.5) | 93 (35.9) | (30.1, 42.1) |
| Prior splenectomy | 3 (12.0) | (2.5, 31.2) | 17 (6.6) | (3.9, 10.3) |
| Baseline anti-romiplostim binding antibodies | 0 (0) | (0.0, 13.7) | 2 (0.8) | (0.1, 2.8) |
| Baseline anti-romiplostim neutralizing antibodies | 0 (0) | (0.0, 13.7) | 0 (0) | (0, 1.4) |
| Previous ITP treatments, median n | 2.0 | [2.0, 3.0] | 2.0 | [2.0, 3.0] |
| Prior rituximab use | 5 (20.0) | (6.8, 40.7) | 54 (20.8) | (16.1, 26.3) |
| Prior corticosteroid use | 23 (92.0) | (74.0, 99.0) | 225 (86.9) | (82.1, 90.7) |
| Medical history | ||||
| Abdominal pain | 0 (0) | (0, 13.7) | 12 (4.6) | (2.4, 8.0) |
| Allergies | 4 (16.0) | (4.5, 36.1) | 31 (12.0) | (8.3, 16.6) |
| Autoimmune neutropenia | 0 (0) | (0, 13.7) | 0 (0) | (0, 1.4) |
| Autoimmune thyroiditis | 0 (0) | (0, 13.7) | 1 (0.4) | (0, 2.1) |
| Chest pain | 0 (0) | (0, 13.7) | 0 (0) | (0, 1.4) |
| Immunodeficiency | 0 (0) | (0, 13.7) | 3 (1.2) | (0.2, 3.3) |
| Kidney disorder | 1 (4.0) | (0.1, 20.4) | 2 (0.8) | (0.1, 2.8) |
| Liver disorder | 0 (0) | (0, 13.7) | 1 (0.4) | (0, 2.1) |
| Musculoskeletal pain | 1 (4.0) | (0.1, 20.4) | 12 (4.6) | (2.4, 8.0) |
| Oropharyngeal pain | 0 (0) | (0, 13.7) | 4 (1.5) | (0.4, 3.9) |
| Pain | 0 (0) | (0, 13.7) | 3 (1.2) | (0.2, 3.3) |
| Thyroid disease | 1 (4.0) | (0.1, 20.4) | 2 (0.8) | (0.1, 2.8) |
Baseline demographic and clinical characteristics were determined for the 284 patients (n = 25 and n = 259) who had received placebo or romiplostim only and patients who received both placebo and romiplostim.
ITP duration was calculated from the time of ITP diagnosis to the time of enrollment in the first ITP study.