Allogeneic hematopoietic stem cell transplantation in patients with multiple myeloma

Aim. To analyze the effectiveness of allogeneic hematopoietic stem cell transplantation (allo-HSCT) from a related HLA-identical donor in patients with multiple myeloma (MM). Materials and methods. From 2013 to 2018, the study included 8 patients (6 men, 2 women) aged from 27 to 55 years (median 39 years) with MM who underwent allo-HSCT from a related HLA-identical donor (7 patients - after auto-HSCT, in 1 case - without previous auto-transplantation). All patients required 2 or more lines of induction therapy, while the achieved antitumor effect was unstable. Before allo-HSCT, complete and very good partial remission was determined in isolated cases, in 4 patients the response was regarded as partial remission, stabilization in 1 observation, progression - in 1 patient. All patients underwent reduced intensity conditioning (fludarabine 30 mg/m(2) x 6 days + busulfan 4 mg/kg x 2 days). Immunosuppressive therapy included the administration of antithymocyte globulin and post-transplant cyclophosphamide. Results. Severe acute GVHD (grade 3-4) was observed in 3 (37.5%) cases, which resulted in death in 1 case. A stable antitumor response was achieved in 5 (62.5%) patients, complete remission lasts for 29-86 months after allo-HSCT. Specific therapy for these patients is not carried out. The 7-year progression-free survival rate was 75%, the 7-year overall survival rate was 84%, with a median follow-up of 65 months. The transplant-related mortality was 12.5%. Conclusion. Allo-HSCT is considered as an alternative method of therapy for young patients with aggressive MM. Allo-HSCT in MM in some cases leads to long-term immunological control of the tumor.