Autologous peripheral blood progenitor cell transplantation with <2 x 10(6) CD34(+)/kg: an analysis of variables concerning mobilisation and engraftment

Optimizing autologous hematopoietic stem cell transplantation for acute leukemia

Autologous hematopoietic stem cell transplantation (ASCT) remains an important postremission treatment for acute leukemia (AL). It is known that some prognostic factors, such as age, cytogenetic and molecular risk stratification, and minimal residual disease (MRD) status, are closely related to clinical outcomes following ASCT. Moreover, there are multiple measurements, including pretransplant treatment, stem cell mobilization and collection, conditioning regimens, and maintenance treatment after transplantation, that can affect prognosis after ASCT. Our clinical practice of ASCT should be better standardized to further improve patient outcomes. This review outlines optimization and quality control measures for ASCT developed at the Institute of Hematology and Blood Diseases Hospital of the Chinese Academy of Medical Sciences, the first established and largest autologous stem cell transplant center in China. These measures will enhance the development of best practices and strategies for AL ASCT therapies, thereby improving patient outcomes.

Autologous Peripheral Blood Stem Cell Transplantation Among Lymphoproliferative Disease Patients: Factors Influencing Engraftment

Objectives

Autologous peripheral blood stem cells transplantation (APBSCT) is a therapeutic option which can be used in various hematological, neoplastic disorders including lymphoproliferative disease (LPD). Differences in patient populations and treatment modalities in different transplant centers mean it is important to improve the knowledge of the different factors affecting engraftment after APBSCT for the success of this procedure. We sought to determine the factors influencing neutrophil and platelet engraftment after APBSCT in patients with LPD.

Methods

We conducted a retrospective review of 70 patients with LPD (35 with lymphoma and 35 with multiple myeloma) who had undergone APBSCT between January 2008 and December 2016. Data obtained included disease type, treatment, and stem cell characteristics. Kaplan-Meier analysis was performed for probabilities of neutrophil and platelet engraftment occurred and was compared by the log-rank test. The multivariate Cox proportional hazards regression model was used for the analysis of potential independent factors influencing engraftment. A p-value < 0.050 was considered statistically significant.

Results

Most patients were ethnic Malay, the median age at transplantation was 49.5 years. Neutrophil and platelet engraftment occurred in a median time of 18 (range 4–65) and 17 (range 6–66) days, respectively. The majority of patients showed engraftment with 65 (92.9%) and 63 (90.0%) showing neutrophil and platelet engraftment, respectively. We observed significant differences between neutrophil engraftment and patient’s weight (< 60/≥ 60 kg), stage of disease at diagnosis, number of previous chemotherapy cycles (< 8/≥ 8), and pre-transplant radiotherapy. While for platelet engraftment, we found significant differences with gender, patient’s weight (< 60/≥ 60 kg), pre-transplant radiotherapy, and CD34+ dosage (< 5.0/≥ 5.0 × 10⁶/kg and < 7.0/≥ 7.0 × 10⁶/kg). The stage of disease at diagnosis (p = 0.012) and pre-transplant radiotherapy (p = 0.025) were found to be independent factors for neutrophil engraftment whereas patient’s weight (< 60/≥ 60 kg, p = 0.017), age at transplantation (< 50/≥ 50 years, p = 0.038), and CD34+ dosage (< 7.0/≥ 7.0 × 10⁶/kg, p = 0.002) were found to be independent factors for platelet engraftment.

Conclusions

Patients with LPD who presented at an early stage and with no history of radiotherapy had faster neutrophil engraftment after APBSCT, while a younger age at transplantation with a higher dose of CD34+ cells may predict faster platelet engraftment. However, additional studies are necessary for better understanding of engraftment kinetics to improve the success of APBSCT.

Analysis of Factors that Influence Hematopoietic Recovery in Autologous Transplanted Patients with Hematopoietic Stem Cells from Peripheral Blood

BACKGROUND:

Successful hematopoietic stem cell transplantation (HSCT) requires a rapid and durable hematopoietic recovery.

AIM:

The aim of our study was to analyse factors that influence hematopoietic recovery after autologous HSCT.

MATERIALS AND METHODS:

Multiple regression analysis was used to analyse factors affecting neutrophil and platelet engraftment in 90 autologous transplanted patients – 30 with acute myeloid leukaemia (AML), 30 with lymphoma and 30 with multiple myeloma (MM) from 2008 till 2016.

RESULTS:

The neutrophil recovery in AML patients was significantly influenced by transfusion support with random-donor platelets, sex and number of transplanted mononuclear cells (MNC) and CD34+ cells; and in lymphoma patients, it was influenced by sex, age, mobilisation strategy and some transplanted MNC. The influence of investigated factors on neutrophil engraftment in MM patients was not statistically significant. The platelet recovery in AML patients was influenced by transfusion support with random-donor platelets; in lymphoma patients, it was influenced by sex, age, time from diagnosis to harvesting and time from diagnosis to HSCT; and in MM patients it was influenced by transfusion support with random-donor platelets.

CONCLUSION:

Additional studies are necessary to better understanding of engraftment kinetic to improve the safety of HSCT and to minimise potential complications and expenses related to HSCT.

Long-term follow up of patients proceeding to transplant using plerixafor mobilized stem cells and incidence of secondary myelodysplastic syndrome/AML

We report the long-term follow up of 49 patients (pts) enrolled on plerixafor compassionate use protocol. Thirty-seven pts (76%) had failed one previous mobilization attempt, while 12 (24%) had failed two or more previous attempts. Using the combination of plerixafor and granulocyte colony-stimulating factor, we collected2.5 × 10(6) CD34+cells/kg in 33 pts (67%). Forty-three of the 49 pts proceeded to an auto-SCT (ASCT). The median days to WBC and platelet engraftment were 11 (range, 9-13 days) and 16 (range, 11-77 days) days post ASCT, respectively. The median WBC count, Hb and platelet counts 1 year after ASCT were 4.7 × 10(9)/L, 12.2 g/dL and 109 × 10(9)/L, respectively. With median follow up of 42 months (range <1-54 months), 21 pts had evidence of disease progression. Five pts developed myelodysplastic syndrome (MDS)/AML at median of 29 months post ASCT. The cumulative incidence of MDS/AML at 42 months was 17% (95% confidence interval, 6 to 32%). Development of secondary MDS/AML in pts proceeding to ASCT after plerixafor mobilization needs to be studied further in a larger cohort.

Hematopoietic stem cell mobilization with the reversible CXCR4 receptor inhibitor plerixafor (AMD3100)-Polish compassionate use experience

Recent developments in the field of targeted therapy have led to the discovery of a new drug, plerixafor, that is a specific inhibitor of the CXCR4 receptor. Plerixafor acts in concert with granulocyte colony-stimulating factor (G-CSF) to increase the number of stem cells circulating in the peripheral blood (PB). Therefore, it has been applied in the field of hematopoietic stem cell mobilization. We analyzed retrospectively data regarding stem cell mobilization with plerixafor in a cohort of 61 patients suffering from multiple myeloma (N = 23), non-Hodgkin’s lymphoma (N = 20), or Hodgkin’s lymphoma (N = 18). At least one previous mobilization attempt had failed in 83.6% of these patients, whereas 16.4% were predicted to be poor mobilizers. The median number of CD34+ cells in the PB after the first administration of plerixafor was 22/μL (range of 0–121). In total, 85.2% of the patients proceeded to cell collection, and a median of two (range of 0–4) aphereses were performed. A minimum of 2.0 × 10⁶ CD34+ cells per kilogram of the patient’s body weight (cells/kg b.w.) was collected from 65.6% of patients, and the median number of cells collected was 2.67 × 10⁶ CD34+ cells/kg b.w. (0–8.0). Of the patients, 55.7% had already undergone autologous stem cell transplantation, and the median time to neutrophil and platelet reconstitution was 12 and 14 days, respectively. Cases of late graft failure were not observed. We identified the diagnosis of non-Hodgkin’s lymphoma and previous radiotherapy as independent factors that contributed to failure of mobilization. The current report demonstrates the satisfactory efficacy of plerixafor plus G-CSF for stem cell mobilization in heavily pre-treated poor or predicted poor mobilizers.

Src family kinase-mediated negative regulation of hematopoietic stem cell mobilization involves both intrinsic and microenvironmental factors

OBJECTIVE

The intracellular signals that contribute to granulocyte colony-stimulating factor (G-CSF) receptor induced stem cell mobilization are poorly characterized.

METHODS

We show enhanced G-CSF induced mobilization of stem cells in mice deficient in expression of Src family kinases (SFK-/-), which is associated with hypersensitivity of SFK-/- bone marrow cells to G-CSF as well as sustained activation of signal transducer and activator of transcription-3.

RESULTS

A proteome map of the bone marrow fluid derived from wild-type and SFK-/- mice revealed a significant global reduction in the number of proteins in SFK-/- mice compared to controls, which was associated with elevated matrix metalloproteinase-9 levels, reduced stromal-derived factor-1 expression, and enhanced breakdown of vascular cell adhesion molecule-1. Transplantation of wild-type or SFK-/- stem cells into wild-type mice and treatment with G-CSF recapitulated the G-CSF-induced increase in stem cell mobilization noted in SFK-/- nontransplanted mice; however, the increase was significantly less. G-CSF treatment of SFK-/- mice engrafted with wild-type stem cells also demonstrated a modest increase in stem cell mobilization compared to controls, however, the observed increase was greatest in mice completely devoid of SFKs.

CONCLUSIONS

These data suggest an involvement of both hematopoietic intrinsic and microenvironmental factors in Src kinase-mediated mobilization of stem cells and identify Src kinases as potential targets for modulating stem cell mobilization.