Blinatumomab therapy for relapsed and refractory acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common oncological disease of childhood. With modern approaches to therapy, approximately 85% of patients with ALL can be considered recovered. However, treatment of relapses and resistant forms of the disease remains a problem. Carrying out high-dosage chemotherapy with subsequent allogeneic TSCS is considered the standard of therapy for such patients. But this is not always effective and, as a rule, is associated with severe concomitant complications. The use of immunotherapy – blinatumomab, a bispecific antibody that allows the patient's own cytotoxic lymphocytes to recognize and destroy leukemia cells, allows achieving full-fledged MRD-negative remission, like a bridge to the TSCC. The effectiveness of blinatumomab probably depends on the composition of the patient's lymphocytes, the presence of CD19 on tumor cells, the number of blast cells in the patient. The article presents own data on the use of blinatumomab in a cohort of patients with refractory and recurrent forms of B-linear ALL and a literature review. The study included 14 patients with refractory ALL from B-progenitors. The median age was 9 years. 8 patients had more than 5% of blasts in the myelogram at the time of onset of therapy with blinatumomab. Blinatumomab was administered at standard dosages in a 28-day continuous infusion. The progression was noted in 1 patient after TSCC and in 2 after HT, all had ≥ 30% of blasts before blinatumomab. The remaining 12 children achieved MRD-negative remission, 11 of them received haploBMT. Of the toxic effects, fever was observed in 80% of cases, 1 case of tremor and 1 case of convulsions. The first Russian experience with the use of blinatumomab in pediatric patients with refractory forms of ALL has proven to be quite successful and may be the basis for subsequent controlled studies both in patients with relapses and, possibly, in some groups of primary diagnosed ALL.