Session: 614. Acute Lymphoblastic Leukemia - Therapy, excluding Transplantation: Clinical Trials
1. Overall efficacy: no leukemic induction failure was observed; 4 induction deaths (0.3%) occurred leading to a 99.7% CR rate. Only 30 out 1097 evaluable pts (2.7%) had a decisional EOI MRD ≥ 1%. Eighty-two relapses have been observed (BM: 47, CNS+: 24, BM+CNS: 9, testis: 2). For the whole population 5-year EFS is 91.5% (95%CI: 89.8-93.3), 5-year OS is 97.4% (95%CI: 96.4-98.4). 5-yr EFS and OS for the A1 and A3 groups are 93.1% vs. 61.2% (p<0.0001), and 98.3% vs. 84.2% respectively (p<0.0001). Five-year DFS of the 30 pts with MRD ≥1% is 58.8% (95%CI: 41.7-82.8). Five-year EFS of the children with ETV6-RUNX1 fusion transcript is 96.6% (95%CI: 94.4-98.8).
2. Overall toxicity: 5 non leukemic deaths have been observed after CR (0.4%). Other main toxicities were attributable to ASPA (CNS thrombosis: 1.5%, grade 3-4 pancreatitis: 0.8%, allergic reaction-all grades- during DI °2: 70%). Six cases of secondary neoplasms were observed (AML: 5 pts, astrocytoma: 1 pt).
3. Randomization: 5y EFS and OS from randomization was 92.9% and 97.2% for D21 M1 pts DNR(+) versus 93.3% and 98.2% for D21 M1 DNR(-) pts (p= 0.89 and p= 0.85, respectively). Interestingly EOI MRD levels in the two arms were not different at the sensitivity cut-off of 10-2 (p=0.93) or 10-3(p= 0.74).
4. Prognostic factors: for the whole population, age < 6 years, WBC < 20.000/mm3, ETV6-RUNX1 positivity, as well as D21 marrow M1 and EOI MRD levels of 10-2 and 10-3 were all associated to EFS in univariate analysis. In multivariate analysis remain only WBC < 20.000/mm3 (p=.001), ETV6-RUNX1 positivity (p=.02), EOI MRD levels ≤ 10-3 (p=1.4x10-5). Considering only randomized pts (D21M1 pts) age <6 (p=.004), WBC < 20.000/mm3 (p=.04), ETV6-RUNX1 positivity (p=.01), EOI MRD levels ≤ 10-3(p=.002) remain as independent prognostic factors in multivariate analysis.
Very good results were obtained with this VCR-DEX-ASPA oriented protocol. SR-BCP ALL pts which represents around 55 % of all children with ALL can be cured with a modest dose of anthracyclin (75 mg/m2). A further decrease in therapy based on the identified prognostic factors could be proposed. Intensification of the chemotherapy for the rare SR pts with a very high MRD has salvaged half of these pts but the addition of new drugs and/or HSCT is now to be evaluated.
Disclosures: No relevant conflicts of interest to declare.
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