A prespecified interim analysis has shown that the primary endpoint of improved overall survival was met in the phase 3 TOWER trial. This randomized, open-label study evaluated the efficacy of the antibody construct blinatumomab (Blincyto, Amgen) compared with standard-of- care chemotherapy in adult patients with Philadelphia chromosome-negative relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL). The study’s independent data monitoring committee recommended, and Amgen has accepted, that the study end early for efficacy.
Patients with ALL have abnormal lymphocytes that crowd out healthy lymphocytes, erythrocytes, and platelets, leading to infection, anemia, fatigue, easy bleeding, and other serious adverse effects.
Blinatumomab is a bispecific CD19-directed CD3 T-cell engager (BiTE) antibody construct that binds specifically to CD19 expressed on the surface of cells of B-lineage origin and to CD3 expressed on the surface of T cells (lymphocytes capable of killing other cells perceived as threats).
BiTE antibody constructs are a type of immunotherapy being investigated for fighting cancer by helping the body’s immune system to detect and target malignant cells. The modified antibodies are designed to engage two different targets simultaneously, thereby juxtaposing T cells to cancer cells. BiTE antibody constructs help place the T cells within reach of the targeted cell, with the intent of allowing T cells to inject toxins and trigger apoptosis of the cancer cell. BiTE antibody constructs are currently being investigated for their potential to treat a variety of cancers.
Blinatumomab was granted breakthrough therapy and priority review designations by the FDA and is approved in the U.S. for the treatment of Philadelphia chromosome-negative relapsed or refractory B-cell precursor ALL.
Source: Amgen; February 4, 2016.