The effects of continued blinatumomab therapy in adult patients with relapsed/refractory acute lymphoblastic leukemia

The study evaluated treatment outcomes in patients with relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) who continued blinatumomab (Blincyto; BL) after initial therapy. The authors found that long-term BL therapy can improve survival in these patients.

45% of adults with ALL experience R/R disease under traditional chemotherapy. Relapse refers to leukemia’s return. Refractory leukemia fails in responding to treatment. BL is an immunotherapeutic drug. It recently showed improved overall survival (OS) in patients after initial treatment, compared to chemotherapy. Some of these patients continued long-term BL-therapy to avoid relapse. However, the treatment outcomes of BL in the long-term are unclear.

The study included 405 adult patients with R/R ALL. 267 received BL and the rest received chemotherapy as initial treatment. Of the 267 patients treated with Bl, 119 achieved a complete remission (CR). 86 of these patients received consolidation or 2^nd round of BL. The rest did not. Consolidation treatment is given after CR is achieved with initial therapy. It is given to kill any cancer cells that may be left, to prevent relapse. 36 patients were given BL maintenance therapy. Maintenance therapy is given help keep cancer from coming back after it has disappeared following the initial therapy.

The average overall survival (OS) was 16.6 months for the consolidation group and 13 months in the no-consolidation group. Patients in no-consolidation had a 29% higher risk of death. Patients with non-consolidation had 6% of higher risks of relapse.

Patients on maintenance therapy were alive when the study ended. Patients in the no-maintenance group had an average OS of 15.5 months and a 63% higher risk of death. On average, survival without relapse was 14.5 months among the maintenance group and 9.8 months among the no-maintenance group. The risk of relapse was 52% higher in the no-maintenance group.

73.3% of patients experienced CR after consolidation therapy. CR was achieved in 83.3% after maintenance therapy. Medical emergencies happened in 72.2% of patients during maintenance, compared with 97.2% in initial therapy and 86.1% in consolidation therapy.

The study concluded that long-term BL therapy can achieve and maintain CR in some patients with R/R ALL. Maintenance therapy with BL improved OS and extended remission in such patients.

This study did not address long-term effects of BL on recovery from leukemic genetic defects. Further long-term studies are needed. This study was funded by Amgen, the manufacturer of blinatumomab.