75% of acute lymphoblastic leukemia patients who had relapsed after standard therapy achieved complete remission with blinatumomab, a medication designed to harness T cells that destroy cancer cells. Blinatumomab makers, Micromet says the drug is “the most advanced of a new class of agents called BiTE® antibodies.”
According to interim results of a Phase II single-arm trial, 9 out of 12 (75%) patients on blinatumomab went into complete remission, or complete remission with partial recovery of blood counts. They achieved a complete molecular response, or had no trace of leukemic cells in their bone marrow. Four patients with genetic abnormalities usually linked to poorer prognoses all achieved complete remission with partial recovery of blood counts.
Chair of the study, Professor Max Topp, Department of Internal Medicine II, University of Wuerzburg, said:
“Relapsed/refractory acute lymphoblastic leukemia is a difficult to treat disease that has seen no meaningful improvement in decades. To date blinatumomab has shown an impressive and unprecedented level of efficacy in a patient population with limited therapeutic options.”
The most common negative side effects were peripheral edema, fatigue and fever. Of the twelve patients, two had to have their treatment interrupted because of fully reversible and manageable CNS (central nervous system) events. One developed cytokine release syndrome, which was dealt with by modifying dosage and administering pre-treatment concomitant medication, after which there were no cases of cytokine release syndrome.
Professor Topp said:
“These results are particularly striking relative to the fact that the majority of enrolled patients had characteristics typically associated with a dismal outlook.”
Standard therapy for those with relapsed/refractory acute lymphoblastic leukemia consists of combination chemotherapy medications, which often fail to achieve remission.
For over three decades no new medication has been approved for relapsing patients. Doctors’ options to improve patients’ long-term outcomes have been very limited.
Current therapies achieve remission rates of between 17% and 45%. Standard chemotherapy typically has a mortality rate of up to 23%. On average, only 7% of acute lymphoblastic leukemia patients survive for at least five years after a relapse.
In this study, patients were given blinatumomab as a continuous infusion for 28 days, followed by two weeks with no treatment. Those who achieve complete remission (CR) or CR with partial recovery of blood counts (CRh) within the first two cycles of treatment may receive consolidation with either 3 more cycles of blinatumomab or allogeneic HSCT.
ALL (Acute Lymphoblastic Leukemia) is a rare cancer in which too many immature malignant white blood cells are produced; these crowd out normal cells in the bone marrow.
Micromet says it will present data at the European Hematology Association Annual Congress meeting in London on Saturday, 11th June.
Blinatumomab is a monoclonal antibody which primes the body’s own killer T-cells to directly attack cancer cells. Monoclonal antibodies are produced by hybridoma cells (a single clone of cells), and are therefore a single type of antibody. In this case the T-cells are directed to destroy CD19, a protein expressed on the surface of B-cell derived from ALLs and non Hogkin’s lymphomas.
5,760 patients are diagnosed with ALL every year in the USA. It is an aggressive cancer of the blood and bone marrow. The patients have abnormal lymphocytes (white blood cells) that are overproduced and crowd out the healthy white and red blood cells and platelets – resulting in anemia, easy bleeding, infections, plus other complications.
Written by Christian Nordqvist