Factors Influencing Outcomes In Patients (Pts) With Relapsed/Refractory B-Precursor Acute Lymphoblastic Leukemia (R/R All) Treated With Blinatumomab In A Phase 2 Study.

7057 Background: Blinatumomab, a bispecific T-cell engager (BiTE) antibody construct, showed efficacy in r/r ALL in a large phase 2 study (Topp et al. Lancet Oncol 2015;16:57). We evaluated associations of baseline characteristics with outcomes. Methods: Pts (≥18 y) had Ph-negative r/r ALL (1st relapse u003c12 mo; relapse u003c12 mo of HSCT; ≥2ndsalvage; refractory). Blinatumomab was given by continuous IV infusion (4 wk/2 wk off) for ≤5 cycles (cycle 1: 9 µg/d days 1–7; then 28 µg/d; subsequent cycles: 28 µg/d). The primary endpoint was complete remission (CR) or CR with partial hematologic recovery (CRh) within 2 cycles. Associations of baseline factors (platelets, prior salvage, bone marrow blasts [BMB], disease stage, age, region, prior HSCT, prior relapse, LDH) with CR/CRh and overall survival (OS) were assessed (Cochran-Mantel-Haenszel test, uni- and multivariate logistic regression). Results: 81 (43%) of 189 pts treated achieved CR/CRh within 2 cycles. Median (95% CI) RFS was 5.9 (4.8–8.3) mo; median OS wa...