Various types of immunotherapies, including modified T cells and antibody-based approaches, are under exploration as potential treatments for patients with acute lymphoblastic leukemia (ALL), Dan Douer, MD, states. Previously, the only cell therapy available was allogeneic transplantation, where donor cells were infused to kill an individual’s leukemia cells.

On December 3, 2014, the FDA approved the anti-CD19 immunotherapy blinatumomab as a treatment for patients with Philadelphia chromosome-negative relapsed/refractory B-precursor ALL, based on findings from a phase II trial. Treatment with blinatumomab demonstrated a complete remission (CR) rate of 32% for a median duration of 6.7 months. Additionally, the rate of CR or CR with partial hematological recovery (CRh) was 42%.

Blinatumomab is a bispecific T-cell engaging antibody that shows the most promise in B-lineage ALL, where it has been utilized in 2 settings, Mark R. Litzow, MD, explains. One setting is in patients who are in hematologic remission with evidence of minimum residual disease (MRD). In these individuals, blinatumomab was able to convert 80% of 20 patients from MRD-positivity to MRD-negativity

Unfortunately, many of the patients who achieved MRD-negativity relapsed, Litzow notes; however, if this agent can aid in getting patients into remission, more can have the opportunity for transplant. Blinatumomab was also studied in high-risk patients with hematologic relapse or refractory disease, where 43% achieved complete remission or complete remission without complete blood count recovery, which led to its initial FDA approval.