Blinatumomab vs historic standard-of-care treatment for minimal residual disease in adults with B-cell precursor acute lymphoblastic leukaemia

Abstract

Objectives: Survival outcomes from a single-arm phase 2 blinatumomab study in patients with minimal residual disease (MRD)-positive B-cell precursor (BCP)-acute lymphoblastic leukaemia (ALL) were compared with those receiving standard of care (SOC) in a historic data set. Methods: The primary analysis comprised adult Philadelphia chromosome (Ph)-negative patients in first complete haematologic remission (MRD ≥ 10−3). Relapse-free survival (RFS) and overall survival (OS) were compared between blinatumomab- and SOC-treatment groups. Baseline differences between groups were adjusted by propensity scores. Results: The primary analysis included 73 and 182 patients from the blinatumomab and historic data sets, respectively. When weighted by age to the blinatumomab-treatment group, median RFS was 7.8 months and median OS was 25.9 months in the SOC-treated group. In the blinatumomab study, median RFS was 35.2 months; median OS was not evaluable. Propensity score weighting achieved balance with seven baseline prognostic factors. With adjustment for haematopoietic stem cell transplantation (HSCT) status, a 50% reduction in risk of relapse or death was observed with blinatumomab vs SOC. Median RFS, unadjusted for HSCT status, was 35.2 months with blinatumomab and 8.3 months with SOC. Conclusions: These analyses suggest that blinatumomab improves RFS, and possibly OS, in adults with MRD-positive Ph-negative BCP-ALL vs SOC.