Table 1.
Demographic and baseline characteristics of patients with CD19-positive or CD19-negative relapsea
| CD19-positive relapse (N = 14) | CD19-negative relapse (N = 4) | |
|---|---|---|
| Sex, n (%) | ||
| Male | 10 (71) | 2 (50) |
| Female | 4 (29) | 2 (50) |
| Geographic region, n (%) | ||
| European Union | 6 (43) | 4 (100) |
| United States | 8 (57) | 0 (0) |
| Age, median (range), years | 6 (1–17) | 8 (5–12) |
| Age group, n (%) | ||
| <2 years | 3 (21) | 0 |
| 2–6 years | 6 (43) | 2 (50) |
| 7–17 years | 5 (36) | 2 (50) |
| Genetic abnormalities, n (%) | ||
| MLL total | 9 (64) | 1 (25) |
| MLL-AF4 t(4, 11) | 2 (14) | 0 |
| Other MLL | 6 (43) | 1 (25) |
| BCR-ABL | 0 (0) | 0 (0) |
| Hypodiploidy | 1 (7) | 0 (0) |
| Constitutional trisomy 21 | 1 (7) | 0 (0) |
| Previous alloHSCT, n (%) | ||
| Yes | 9 (64) | 1 (25) |
| No | 5 (36) | 3 (75) |
| Previous relapses, n (%) | ||
| 1 | 4 (29) | 1 (25) |
| 2 | 8 (57) | 2 (50) |
| ≥3 | 2 (14) | 1 (25) |
| Refractory disease, n (%) | 14 (100) | 4 (100) |
| Yes | 0 (0) | 0 (0) |
| No | 14 (100) | 4 (100) |
| Time between last relapse and first blinatumomab infusion, median (range), months | 0.9 (0.1–10.2) | 0.8 (0.3–2.3) |
| Relapse within 6 months after last prior treatment attempt, n (%) | 4 (29) | 2 (50) |
| Bone marrow blast count (central laboratory), n (%) | ||
| <50% | 6 (43) | 1 (25) |
| ≥50% | 8 (57) | 3 (75) |
alloHSCT allogeneic hematopoietic stem cell transplantation; BCR-ABL breakpoint cluster region-Abelson murine leukemia viral oncogene homolog 1 gene; MLL mixed-lineage leukemia gene. aFlow data from one patient was unavailable