Patient characteristics of the 234 children with de novo AML included in this study
. | Study population . | FLT3/ITD-positive patients . | Patients with successful drug-resistance assay . |
|---|---|---|---|
| No. (%) | 234 | 27 (11.5) | 134§ |
| WBC at diagnosis, median (P25-P75), × 109/L | 30.5 (11.8-94.2) | 50.3 (21.2-117.3) | 39.9∥ (15.2-117.4) |
| Male/female ratio | 126:108 | 18:9 | 68:66 |
| Age at diagnosis, median (P25-P75), y | 8.8 (2.8-13.2) | 13.4* (10.7-15.2) | 8.7∥ (3.2-13.3) |
| AML-BFM risk groups | |||
| SR | 80 | 9 | 54 |
| HR | 154 | 18 | 80 |
| FAB | |||
| M0 | 9 | 1 | 6 |
| M1 | 27 | 6† | 15 |
| M2 | 69 | 10† | 37 |
| M3 | 9 | 2 | 6 |
| M4 (Eo+) | 55 (21) | 5 (0) | 41 (17) |
| M5 | 53 | 2† | 27 |
| M6 | 4 | 1 | 1 |
| M7 | 8 | 0 | 1 |
| Cytogenetic analysis | |||
| Normal | 54 | 12‡ | 32 |
| t(8;21) | 25 | 1 | 10 |
| inv(16) | 12 | 0 | 10 |
| t(15;17) | 5 | 1 | 3 |
| 11q23 abnormalities | 34 | 0‡ | 8 |
| Single random abnormalities | 25 | 5 | 12 |
| Multiple abnormalities | 27 | 1 | 11 |
| Abnormalities of chromosome 5 or 7 | 8 | 0 | 5 |
| Trisomy 8 alone | 7 | 2 | 5 |
| Unknown | 37 | 5 | 28 |
| Treatment protocol | |||
| AML-BFM 87 | 3 | 0 | 3 |
| AML-BFM 93 | 79 | 9 | 64 |
| AML-BFM 98 | 83 | 13 | 18 |
| DCLSG-ANLL 87 | 9 | 3 | 11 |
| DCLSG-ANLL 94 | 60 | 2 | 38 |
. | Study population . | FLT3/ITD-positive patients . | Patients with successful drug-resistance assay . |
|---|---|---|---|
| No. (%) | 234 | 27 (11.5) | 134§ |
| WBC at diagnosis, median (P25-P75), × 109/L | 30.5 (11.8-94.2) | 50.3 (21.2-117.3) | 39.9∥ (15.2-117.4) |
| Male/female ratio | 126:108 | 18:9 | 68:66 |
| Age at diagnosis, median (P25-P75), y | 8.8 (2.8-13.2) | 13.4* (10.7-15.2) | 8.7∥ (3.2-13.3) |
| AML-BFM risk groups | |||
| SR | 80 | 9 | 54 |
| HR | 154 | 18 | 80 |
| FAB | |||
| M0 | 9 | 1 | 6 |
| M1 | 27 | 6† | 15 |
| M2 | 69 | 10† | 37 |
| M3 | 9 | 2 | 6 |
| M4 (Eo+) | 55 (21) | 5 (0) | 41 (17) |
| M5 | 53 | 2† | 27 |
| M6 | 4 | 1 | 1 |
| M7 | 8 | 0 | 1 |
| Cytogenetic analysis | |||
| Normal | 54 | 12‡ | 32 |
| t(8;21) | 25 | 1 | 10 |
| inv(16) | 12 | 0 | 10 |
| t(15;17) | 5 | 1 | 3 |
| 11q23 abnormalities | 34 | 0‡ | 8 |
| Single random abnormalities | 25 | 5 | 12 |
| Multiple abnormalities | 27 | 1 | 11 |
| Abnormalities of chromosome 5 or 7 | 8 | 0 | 5 |
| Trisomy 8 alone | 7 | 2 | 5 |
| Unknown | 37 | 5 | 28 |
| Treatment protocol | |||
| AML-BFM 87 | 3 | 0 | 3 |
| AML-BFM 93 | 79 | 9 | 64 |
| AML-BFM 98 | 83 | 13 | 18 |
| DCLSG-ANLL 87 | 9 | 3 | 11 |
| DCLSG-ANLL 94 | 60 | 2 | 38 |
FLT3/ITD was detected in 27 samples. In addition, the clinical characteristics of the subgroup of 134 children (15 with and 119 without FLT3/ITD) with successful cellular drug-resistance assay are given.
P25-P75 indicates 25th to 75th percentiles.
FLT3/ITD-positive patients were significantly older than FLT3/ITD-negative patients (median, 13.4 vs 8.8 years; P < .001). In addition, the frequency of FLT3/ITD was age dependent (“Results”).
Samples with normal karyotype were found in 54.5% of FLT3/ITD-positive samples versus 24.7% of FLT3/ITD-negative samples (P = .003), and no FLT3/ITD was found in any of AML samples with 11q23 abnormalities (P = .02).
FAB M1/M2 was found in 59% of FLT3/ITD-positive samples versus 39% in the FLT3/ITD-negative group (P = .04). M5 was found in 7% of FLT3/ITD-positive samples versus 23% in the FLT3/ITD-negative group (P = .04).
Includes 15 FLT3/ITD-positive patients.
Patients with successful drug-resistance assay were significantly older (8.7 vs 3.9 years; P = .009) and had higher WBC counts at diagnosis (39.9 × 109/L vs 13.8 × 109/L; P < .001) compared with those without successful assay.