Acute lymphoblastic leukemia (ALL) is a rare but aggressive cancer of the blood with approximately 6,020 new cases diagnosed in the US each year (Siegel et al, 2014) and median overall survival of only 3 to 5 months for adults who are refractory to or have relapsed after front-line chemotherapy (Kantarjian et al, 2010; O’Brien et al, 2008.) Blincyto® (blinatumomab) is a bispecific T-cell engager (BiTE®) antibody construct that was granted Breakthrough Therapy Designation by the FDA in 2014 for the treatment of relapsed or refractory (r/r) ALL and was granted accelerated approved by the FDA later in that same year (only 75 days after submission of the Biologics License Application.) In this talk, the development program for Blincyto will be discussed with a special emphasis on study design considerations, the use of historical data, and the statistical methods used to evaluate historical data in the context of clinical trial data.