Effect of anti-CD19 BiTE blinatumomab on complete remission rate and overall survival in adult patients with relapsed/refractory B-precursor ALL.

6500^ Background: Blinatumomab is a bispecific T-cell engaging (BiTE) antibody that directs cytotoxic T-cells to CD19 expressing target cells. Methods: In adult patients with relapsed/refractory B-precursor ALL, a phase II dose ranging trial is being conducted to evaluate efficacy and safety of blinatumomab. The primary endpoint is the rate of hematological complete remission (CR) or CR with partial hematological recovery (CRh*) within 2 cycles of blinatumomab treatment. Blinatumomab is administered by continuous intravenous infusion for 28-days followed by a 14-day treatment-free interval. Responding patients can receive 3 additional cycles of treatment or proceed to bone marrow transplantation. Three dose levels were explored as shown in the table. Results: In total 36 patients have been enrolled, 25 are currently evaluable. Seventeen out of 25 treated patients (68%) reached a hematological CR/CRh* and a minimal residual disease (MRD) response (MRD level <10-4) within the first 2 cycles. Five out of 17 ...