Leukemia Drug Blinatumomab Receives ‘Breakthrough Therapy’ Designation
Antibody targets cancer proteins
The FDA has granted a “breakthrough therapy” designation to blinatumomab (Amgen), an investigational bispecific T cell engager (BiTE) antibody for adults with Philadelphia-negative (Ph–) relapsed/refractory B-precursor acute lymphoblastic leukemia (ALL), a rapidly progressing cancer of the blood and bone marrow.
The new designation was based on results from a phase II trial involving 189 adult patients with Ph– relapsed/refractory B-precursor ALL treated with blinatumomab. Data from this study were presented at the 50th Annual Meeting of the American Society of Clinical Oncology (ASCO).
According to the FDA, the classification of an investigational treatment as a “breakthrough therapy” is intended to expedite the development and review of drugs for serious or life-threatening conditions. The criteria for this designation require preliminary clinical evidence demonstrating that the drug may offer substantial improvement on at least one clinically significant endpoint compared with available therapy.
Blinatumomab is an investigational BiTE antibody designed to direct the body’s cell-destroying T cells against target cells expressing CD19, a protein found on the surface of B cell-derived leukemias and lymphomas.
The antibody has received an “orphan drug” designation from the FDA for the treatment of ALL, chronic lymphocytic leukemia (CLL), hairy cell leukemia, prolymphocytic leukemia, and indolent B-cell lymphoma. It is also being investigated for its potential to treat pediatric relapsed/refractory ALL, relapsed/refractory Philadelphia-positive (Ph+) B-precursor ALL, minimal residual disease-positive (MRD+) B-precursor ALL, and relapsed/refractory non-Hodgkin’s lymphoma (NHL), including relapsed/refractory diffuse large B-cell lymphoma (DLBCL).
BiTE antibodies are a type of immunotherapy being investigated for use in fighting cancer by helping to engage 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 (a type of white blood cell capable of killing other cells perceived as threats) to cancer cells. BiTE antibodies help place the T cells within reach of the targeted cell, with the intent of allowing them to inject toxins and to trigger apoptosis. BiTE antibodies are currently being investigated for their potential to treat a wide variety of cancers.
It has been estimated that more than 6,000 cases of ALL were diagnosed in the U.S. in 2013. In adult patients with relapsed or refractory ALL, median overall survival is 3 to 5 months.
Source: Amgen; July 1, 2014.