Blinatumomab: A new monoclonal antibody therapy as a treatment option for relapsed B-cell ALL

This study examined remission rates with blinatumomab (Blincyto) treatment in patients with relapsed adult acute lymphoblastic leukemia (ALL). Researchers concluded that blinatumomab can achieve complete remission in patients with unfavorable ALL. However, this was an early-phase trial and more studies are needed.

Chemotherapy is the first-line treatment of ALL. Unfortunately, many patients may experience relapse (the disease returns). 30% to 45% of these patients can achieve a second complete remission with further chemotherapy. However, stem cell transplantation is considered the most effective therapy for adults with ALL who have relapsed or who have progressed despite treatment. Patients must regain complete remission before they can undergo transplantation.

Blinatumomab is a newly developed type of immunotherapy called a monoclonal antibody. Monoclonal antibodies are made in the laboratory from a single type of immune system cell. These antibodies can identify substances on cancer cells or normal substances in the body involved in cancer growth. The effectiveness of blinatumomab in helping patients with relapsed or unfavorable ALL achieve complete remission is still being investigated.

The aim of this study was to examine the effectiveness of blinatumomab for relapsed ALL.

189 ALL patients were included in this study. Patients had either relapsed or were no longer responding to standard therapy. Patients were treated with continuous blinatumomab infusions over 4 weeks every 6 weeks for up to 5 cycles. The rate of patients achieving complete remission over the first 2 treatment cycles was recorded.

After 2 cycles, 81 patients (43%) achieved complete remission. 18 of these patients also achieved partial recovery of blood counts. 64 of the 81 responders (79%) achieved complete remission in the first treatment cycle. 40% of the patients who reached complete remission later underwent stem cell transplantation.

45% of the patients who had achieved complete remission were still alive and in remission after an average follow-up of 8.9 months. The remaining patients either relapsed (37 patients) or died without documented relapse (7 patients). 6 of the 7 patients died after undergoing a stem cell transplant and 1 patient died of infection.

Average overall survival (time from treatment until death from any cause) was 6.1 months across all patients. The average time to relapse was 5.9 months for those patients who achieved remission.

The most common serious side effects were low neutrophil (type of white blood cell) levels with or without fever (16% to 25%) and low hemoglobin levels in the blood (14%). Neurologic side effects considered serious included tremors, dizziness, confusion, movement disorders, and convulsions (between 2 and 11%). 3 deaths (due to sepsis or infection) were considered to be treatment-related.

Researchers concluded that blinatumomab can achieve complete remission in some patients with unfavorable ALL.

Some of the authors of this study are affiliated with the manufacturers of blinatumomab. This was an early-phase trial and more studies are needed to confirm these preliminary results.