Patients With Relapsed or Refractory ALL Benefit From Blinatumomab

A new study demonstrated efficacy of blinatumomab (Blincyto) in treating patients diagnosed with Philadelphia chromosome-negative relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL). Patients with this diagnosis often face a grim prognosis because of abnormal white blood cells that crowd out healthy white blood cells, red blood cells and platelets, leading to infection, anemia, bleeding, and other side effects.

The TOWER study was a phase III, randomized, open-label study that compared the BiTE® antibody blinatumomab versus standard-of-care chemotherapy in adults. Blinatumomab is a bispecific CD19-directed CD3 T-cell engager antibody construct that binds to CD19 expressed on the surface of cells of B-lineage origin and CD3 expressed on the surface of T cells.

Patients were randomly selected in a 2:1 ratio to receive blinatumomab or treatment with the investigator’s choice of one of four protocol-defined chemotherapy regimens.

"This is the first study to demonstrate an overall survival benefit for these patients with an immunotherapy, and this is a tremendously rare achievement in relapsed and refractory ALL," said Sean E. Harper, MD, executive vice president of Research and Development at Amgen, in a press release. "We will work with regulatory authorities towards a full approval for Blincyto in this population."

Serious adverse events from blinatumomab included cytokine release syndrome, which can be deadly; neurological toxicities; infections; tumor lysis syndrome, which can be fatal; neutropenia, sometimes with fever; elevated liver enzymes; and leukoencephalopathy. The most commonly reported adverse events in approximately 20% of clinical trial participants were pyrexia (62%), headache (36%), peripheral edema (25%), febrile neutropenia (25%), nausea (25%), hypokalemia (23%), rash (21%), tremor (20%), diarrhea (20%), and constipation (20%).

The primary endpoint was overall survival. Secondary endpoints are currently being evaluated and data will be shared in upcoming medical conferences and publications.