Development of a quantitative prediction model for peripheral blood stem cell collection yield in the plerixafor era

Predictive factors for peripheral blood stem cell mobilization in multiple myeloma in the era of novel therapies: A single-center experience

OBJECTIVE

Multiple myeloma (MM) is the leading indication of autologous hematopoietic stem cell transplantation. The aim of this study was to determine the incidence of mobilization failure and characterize the risk factors associated with poor mobilization (PM) of MM patients in novel therapies era.

METHODS

We conducted a retrospective study of 211 MM patients who received their first peripheral blood stem cells (PBSC) mobilization at our single center. The following data were collected: age, gender, clinical stage, disease status, complete blood cell count, induction regimen, CD34+ cell count in peripheral blood (PB), and PBSC collections.

RESULTS

In addition to conventional drugs, 22 (10.4%) patients received daratumumab containing induction, and 33 (15.6%) patients used plerixafor for poor mobilization (pre-apheresis PB CD34+ cells <20/μL). Failure of collection occurred in 24 (11.4%) patients and was correlated with low white blood cell (WBC), ≥3 cycles of lenalidomide treatment before mobilization, steady-state mobilization and nouse of plerixafor are associated with mobilization failure. Daratumumab-based induction treatment ≥2 courses, albumin >41 g/L before mobilization, and steady-state mobilization were risk factors for PM in subgroups of patients treated with lenalidomide for <3 courses. In addition, Hepatitis B virus infection at baseline, thalassemia and measurable residual disease positivity were recognized as predictive factors for PM in subset of chemo-mobilization patients.

CONCLUSION

In addition to some well-recognized risk factors, baseline WBC count and daratumumab exposure ≥2 courses before mobilization were revealed as the predictive factors of mobilization failure, providing consultation for preemptive use of plerixafor.

Analysis of Factors Affecting Hematopoietic Stem Cell Mobilization Efficiency and Early Hematopoietic Reconstruction Indicators during Autologous Peripheral Blood Hematopoietic Stem Cell Transplantation

Purpose  To analyze the factors affecting the mobilization efficiency of hematopoietic stem cells and hematopoietic reconstruction indicators during autologous peripheral hematopoietic stem cell transplantation. Methods  The clinical data of 54 patients who underwent autologous peripheral blood hematopoietic stem cell mobilization and transplantation at Xuzhou Central Hospital from May 2016 to April 2023 were retrospectively analyzed. The gender, age, disease type, mobilization regimen, number of chemotherapy sessions, G-CSF (granulocyte colony-stimulating factor) dosage, and platelet number at the time of collection were also collected. Moreover, the relationship between these indicators with mobilization results and hematopoietic reconstruction was analyzed. Results  Results showed that age, disease type, and number of collections were significantly related to the mobilization results (number of CD34+ hematopoietic stem cells). Furthermore, multivariate analysis showed that the number of collections was an independent factor affecting mobilization efficiency. Similarly, age, platelet value at the time of collection, CD34+ stem cell value during collection, white blood cell count, and number of chemotherapy times were significantly related to the time of megakaryocytic hematopoietic reconstruction. Multifactor analysis found that age and platelet count were independent factors affecting the reconstruction time of the megakaryocytic system. However, no factor was related to the time of granulocyte hematopoietic reconstruction. Conclusion  Platelet count and age when collecting hematopoietic stem cells are closely related to megakaryocytic hematopoietic reconstruction and are key indicators of early hematopoietic reconstruction after autologous hematopoietic stem cell transplantation.

Predicting the CD34 content of mobilized peripheral blood leukapheresis products: single institution experience over 20 years

BACKGROUND AIMS

Since the standardization of CD34 measurement by flow cytometry, predictors of leukapheresis CD34 yield have played a pivotal role in planning donor leukaphereses. We describe here a single institution's experience with a multivariate predictor that was used for 2,929 products without alteration for 20 years.

METHODS

The ordinary least squares regression model variables included log peripheral CD34 count, collection duration (3- versus 4-hours), collection number, donor sex, and transplant type.

RESULTS

During the study period we changed flow cytometers twice and leukapheresis instruments once. During the Cobe Spectra era the predictor explained 90% of the variability in CD34 collection yield for autologous transplants (r2 = 0.90), and 70% for allogeneic transplants with an overall sensitivity to predict a CD34 yield of ≥ 1 × 106/kg of 97.7%, and specificity of 81.4%.

CONCLUSIONS

Implemented prospectively with real-time result reporting, the model allowed us to predict CD34 yield with both 3- and 4-hour collection scenarios. Given this guidance, 3-hour collections were selected by the clinical team 25% of the time, saving patient leukapheresis time and resources. When faced with a prediction of < 1 × 106 CD34/kg, the clinical team chose to defer collection 72% of the time. In instances where leukapheresis was performed despite a poor predicted outcome, 85% of patients collected on the Cobe Spectra, and 92% of patients collected on the Optia, failed to collect at least 1 × 106 CD34/kg. A revised model is tested retrospectively on Optia data, and suggestions for further improvements are discussed.

Benefits of plerixafor for mobilization of peripheral blood stem cells prior to autologous transplantation: a dual-center retrospective cohort study

BACKGROUND AIMS

Before autologous stem cell transplantation (ASCT), hematopoietic stem cells must be stimulated to move from the bone marrow to the peripheral blood for harvesting. Plerixafor, a C-X-C chemokine receptor type 4 antagonist, is used to increase stem cell harvests. However, the effects of plerixafor on post-ASCT outcomes remain unclear.

METHODS

In a dual-center retrospective cohort study of 43 Japanese patients who received ASCT, the authors compared transplantation outcomes in patients who underwent stem cell mobilization with granulocyte colony-stimulating factor with (n = 25) or without (n = 18) plerixafor.

RESULTS

The number of days to neutrophil and platelet engraftment was significantly shorter with plerixafor than without plerixafor, as assessed by univariate (neutrophil, P = 0.004, platelet, P = 0.002), subgroup, propensity score matching and inverse probability weighting analyses. Although the cumulative incidence of fever was comparable with or without plerixafor (P = 0.31), that of sepsis was significantly lower with plerixafor than without (P < 0.01). Thus, the present data indicate that plerixafor leads to earlier neutrophil and platelet engraftment and a reduction of infectious risk.

CONCLUSIONS

The authors conclude that plerixafor may be safe to use and that it reduces the risk of infection in patients with a low CD34+ cell count the day before apheresis.

Day -1 CD34+ Cells and Platelet Count Predict the Number of Apheresis in Poor-Mobilizer Patients Rescued by Plerixafor

Plerixafor is widely used as up-front treatment with G-CSF to enhance peripheral blood hematopoietic stem cell output in patients failing previous mobilizations. Less frequently, plerixafor is used to rescue an unsatisfactory mobilization following chemotherapy (CT) and G-CSF. This study investigates if pre-collection factors affect the CD34+ cell harvest in chemotherapy and G-CSF mobilizations rescued by plerixafor. Clinical and hematological data relative to patients, mobilization, and apheresis products were retrospectively examined. The outcome was completing a target cell dose ≥ 2 × 10⁶ CD34+ cells/kg at first apheresis. The effect exerted on the outcome by patient- and disease-related factors was investigated by univariate and multivariate logistic regression analysis. The analysis included data from 42 patients affected by hematological (39 patients) and non-hematological malignancies (three patients). Twenty-nine patients (69%) attained the target cell dose at first apheresis. Twelve out of the remaining 13 patients received an additional plerixafor administration, and all accomplished the transplant dose at a second apheresis procedure. Day -1 CD34+ PB count (OR1.46, 95% CI 1.1-1.9, p = 0.008) and platelet count (OR1.0, 95% CI 1.0-1.0, p = 0.033) predicted the achievement of the target dose at first apheresis, independently of pre-mobilization CT, radiation therapy, and disease status at mobilization. At ROC curve analysis, the best cut-off value predicting the successful collection at first apheresis was 7.5/µL for Day -1 CD34+ cell count (AUC 0.830, 0.69 sensitivity, and 0.92 specificity) and 75 × 10⁹/L for Day -1 platelet count (AUC = 0.736, 0.65 sensitivity and 0.85 specificity). In conclusion, on-demand plerixafor rescue allows a successful stem cell collection, irrespectively of disease type and status, prior CT lines, and radiation exposure. Pre-apheresis CD34+ cells and platelet count predict the need for one or two aphereses.

Hematopoietic Stem Cell Gene-Addition/Editing Therapy in Sickle Cell Disease

Autologous hematopoietic stem cell (HSC)-targeted gene therapy provides a one-time cure for various genetic diseases including sickle cell disease (SCD) and β-thalassemia. SCD is caused by a point mutation (20A > T) in the β-globin gene. Since SCD is the most common single-gene disorder, curing SCD is a primary goal in HSC gene therapy. β-thalassemia results from either the absence or the reduction of β-globin expression, and it can be cured using similar strategies. In HSC gene-addition therapy, patient CD34+ HSCs are genetically modified by adding a therapeutic β-globin gene with lentiviral transduction, followed by autologous transplantation. Alternatively, novel gene-editing therapies allow for the correction of the mutated β-globin gene, instead of addition. Furthermore, these diseases can be cured by γ-globin induction based on gene addition/editing in HSCs. In this review, we discuss HSC-targeted gene therapy in SCD with gene addition as well as gene editing.