Factors Associated with Efficient Harvesting and Engraftment of Auto-Transplants in Multiple Myeloma Patients

Background. The success of autologous hematopoietic stem cell transplantation (auto-HSCT) depends on the speed of transplant engraftment which in turn is affected by the count of harvested and infused hematopoietic stem cells (HSC). Aim. To identify predictors of auto-HSCT efficacy in multiple myeloma (MM) patients under introduction of new drugs at the phase of HSC induction and mobilization. Materials & Methods. The results of auto-transplant harvesting and engraftment were retrospectively analyzed in 75 MM patients during 112 auto-HSCTs. Auto-transplants were harvested using cyclophosphamide and vinorelbine combined with granulocyte colony-stimulating factor (G-CSF) without plerixafor. Conditioning regimen included melphalan 200 mg/m2 or 140 mg/m2, and combination of tiothepa with melphalan. All patients received subcutaneous injections of G-CSF in post-transplantation period. Transplant engraftment was assessed according to absolute neutrophil count of ≥ 0.5 × 109/L, and thrombocyte count of ≥ 20 × 109/L. Results. It is established that the predictors of a high CD34+ cell count in auto-transplant are a single previous induction regimen (p = 0.0315) and administration of cyclophosphamide in mobilization regimen (р = 0.0001). Transplant engraftment period is determined by auto-HSCT serial number and amount of infused CD34+ cells. Hematopoiesis regeneration after the second auto-HSCT was accelerated by more frequent use of Mel140 (р = 0.001). Conclusion. Auto-transplant quality and engraftment period in MM patients primarily depend on the efficacy of induction therapy and the intensity of HSC mobilization regimen. Therefore, induction therapy and mobilization regimen need to be tailored to an individual patient, MM prognostic variant, probability of response to standard induction regimens, and the number of planned auto-HSCTs

Hematopoietic Stem Cell Collection in Multiple Myeloma Patients: Influence of the Lenalidomide-Based Therapy and Mobilization Regimen Prior to Auto-HSCT

Background. A prompt graft acceptance is essential for positive autologous hematopoietic stem cell transplantation (auto-HSCT) outcome in multiple myeloma patients (MM). Prompt and favourable hematopoietic regeneration is associated with CD34+ cell count in a transplant. Although the indicators of low autotransplant cellularity have been defined, the practical application of new drug products and HSC mobilization regimens strengthens the relevance of determining their influence on the transplant quality. Aim. To determine the factors that are associated with low efficacy of auto-HSCT in MM patients and to evaluate the impact of lenalidomide during induction period and of vinorelbine as a mobilization regimen on the prognosis. Materials & Methods. The authors performed a retrospective analysis of autotransplant collection results in 68 MM patients treated with two mobilization regimens: 3 g/m2 cyclophosphamide with granulocyte colony-stimulating factor (G-CSF) and 30 mg/m2 vinorelbine with G-CSF. Mobilization was aimed at collecting not less than 2–4 × 106 CD34+ cells per kg body mass. CD34+ cell count was determined by four-color analysis on the Cytomics FC 500 laser flow cytometer. Results. The analysis showed that age or MM immunochemical specificity were not associated with CD34+ cell count in the transplant. Prior lenalidomide treatment compared to therapy without immunomodulators (4.1 × 106/kg vs. 7.76 × 106/kg) tends to decrease CD34+ count (р = 0.066). Cyclophosphamide included into mobilization regimen compared to vinorelbine (3.96 × 106/kg vs. 6.8 × 106/kg) significantly increased CD34+ cell count (р = 0.022). Conclusion. The decrease of CD34+ cell count in the autotransplant of the MM patients treated with lenalidomide prior to auto-HSC collection, and a lower mobilization activity of vinorelbine provide a basis for a differentiated selection of mobilization regimens. Vinorelbine may be administered to patients with a single auto-HSCT, i.e. elderly people and patients with complete response. In case of substantial lenalidomide treatment prior to auto-HSCT, intermediate-dose cyclophosphamide is preferred

Correlation of CD34+ Hematopoietic Stem Cells and CFU in Peripheral Blood Apheresis Products in Patients with Malignant Lymphoproliferative Diseases Before and After Cryopreservation Prior to auto-HSCT

Aim. To establish correlation between CD34+ autologous hematopoietic stem cell (HSC) count and colony-forming units (CFU) in the same peripheral blood apheresis product samples before and after cryopreservation in multiple myeloma and lymphoma patients, and to assess clinical value of these parameters. Materials & Methods. Cell samples of peripheral blood cytapheresis product and cell cultures were studied before and after cryopreservation in 32 multiple myeloma and 25 lymphoma patients who underwent autologous HSC transplantation. The material was analyzed using culture technique and flow cytometry. Results. The paper provides information on the relationship between CD34+ HSC count obtained by flow cytometry, and CFU in cell culture obtained by cytapheresis of the same peripheral blood samples. A direct correlation was confirmed between CD34+ count and all the CFUs before and after cryopreservation in lymphoma patients. Correlation between CD34+ count and granulocyte-macrophage CFUs was revealed in multiple myeloma and lymphoma patients before cryopreservation. Conclusion. The parameter of colony-forming capacity used for the assessment of the functional HSC was shown to be equally reliable criterion for condition evaluation of autotransplant proliferative pool than CD34+ cells. Both methods should be applied for qualitative and quantitative evaluation of an autotransplant for multiple myeloma and lymphoma patients

Low Dose Cytarabine and Cladribine for Treatment of Relapsed or Refractory Acute Myeloid Leukemia: Clinical Experience

Aim. The aim of this paper is to evaluate the effectiveness of low dose cytarabine (Ara-C) combined with cladribine for the treatment of relapsed or refractory acute myeloid leukemia (AML) and to determine clinical and lab factors associated with response to the therapy. Methods. Data of 10 patients aged 26–58 years (median 48 years) were analyzed. The diagnoses were de novo AML (7 patients), secondary AML (sAML) (2 patients) and refractory anemia with excess of blasts (RAEB-2) (1 patient). Four patients had primary refractory AML. Relapse was diagnosed in 3 patients. The induction scheme 7+3 was ineffective in patient with RAEB-2. There was no response to any kind of therapy in sAML patients. The treatment scheme under trial consisted of Ara-C 10–15 mg/m2 subcutaneously twice a day for 1–14 days and cladribine 5 mg/m2 intravenously once a day for 1–5 days. The course was repeated in case of at least two-fold decrease in bone marrow blasts level in a punctate versus baseline. Medical examination and maintenance therapy were performed in accordance with protocols approved by the clinic. Results. According to the protocol, the patients received 1–2 courses. Response was achieved in 5 patients: 2 patients achieved complete response (CR) and 3 achieved partial response (PR). The most common complication was hematologic toxicity. All patients received transfusions of blood components. No lethal outcomes were observed within 8 weeks. The duration of the response was 2 to 3 months. During this period of time, allogeneic stem cell transplantation was performed in 2 patients with CR; however, in one patient, the conditioning regimen began at the same time with the increase in blast cell count in the bone marrow. The search for unrelated donors of hematopoietic stem cells for 2 patients with CR was begun. The distinct features of all patients with CR and PR were the following factors: de novo AML, absence of FLT3 or c-KIT mutations and the course duration was not less than 10 days. Conclusion. Low dose Ara-C in combination with cladribine may be considered a treatment option for some patients with relapsed or refractory de novo AML