Adequate Engraftment With Lower Hematopoietic Stem Cell Dose

Personalized autologous stem cell harvesting improves patient collection outcomes

OBJECTIVES

This study aims to demonstrate that utilizing a personalized approach to apheresis stem cell collection, can safely optimize the collection outcomes, especially in the context of poor mobilizers and high cell targets.

BACKGROUND

The optimal mobilization and harvesting of peripheral blood stem cells is critical to the success of the stem cell transplant. The ideal strategy that promotes better cell yields, with sustainable use of resources and assuring patient safety, should be pursued.

METHODS

PBSC collections for autologous stem cell transplant data according to a fixed-processed volume strategy (One Size Fits All) or individualized to patients CD34+ peripheral blood content and target approach (Custom-Tailored or CT) were retrospectively compared.

RESULTS

A total of 263 collections from 142 patients were assessed. The majority of patients were male, had multiple myeloma and were mobilized with isolated G-CSF. The CT strategy promoted a significantly higher CD34+ cell yield when the pre-collection CD34 was lower than 20/µl (1.02 ± 0.16 versus 1.36 ± 0.23, p < 0.001) and also a decrease in the proportion of mobilization cycles that needed 3 apheresis (31% versus 14%, p = 0.02). There was no difference in apheresis-related adverse events between the groups.

CONCLUSION

Tailoring the apheresis procedures to the patient-specific characteristics and objectives, can effectively promote better patient outcome.

A critical assessment of dose effects of post-thaw CD34 on autologous stem cell transplantation treatment of haematological malignancies

A consensus threshold of pre-cryopreservation CD34-positive cells (CD34s) has been used as the minimum dose to initiate autologous stem cell transplantation (ASCT). Advances in cryopreservation posed a debate whether post-thaw CD34s might be a superior surrogate instead. We addressed the debate in this retrospective study of 217 adult ASCTs in five different haematological malignancies treated at a single centre. We showed that post-thaw CD34s was highly correlated with pre-cryopreservation CD34s (r = 0.97) and explained ∼2.2% (p = 0.003) of the variation of the post-thaw total nucleated cell viability that however had no power to predict engraftment outcomes. After stratifying the ASCT cases into four dose groups based on post-thaw CD34s reinfused, stepwise multivariate regression analyses detected significant effects in dose group and interactions with diseases for neutrophil and platelet recovery respectively. The significant dose effects and interactions were triggered by two technical outliers in the low dose group, and disappeared in the repeated regressions after exclusion of the outliers where disease and age were the significant predictors remained. Our data clearly support the validity of the consensus threshold in ASCT applications but also highlight neglected conditions where monitoring post-thaw CD34s and clinical attributes are valuable.

Outcomes of Non-Cryopreserved Versus Cryopreserved Peripheral Blood Stem Cells for Autologous Stem Cell Transplantation in Multiple Myeloma

BACKGROUND Autologous stem cell transplantation (ASCT) has become a standard procedure in multiple myeloma (MM) patients. Cryopreservation (CRYO) of stem cells may be associated with adverse reactions of dimethyl sulfoxide. Previous studies showed that stem cell storage at 4°C (non-cryopreserved [NC] method) may have some advantages. This analysis focused on comparing the transplant-related outcomes of the 2 preservation methods. MATERIAL AND METHODS This was a cohort study of consecutive MM patients who underwent ASCT at Chiang Mai University from 2014 to 2019. Primary outcomes were time to neutrophil and platelet engraftment. Key secondary outcomes were the incidence of infusion reactions, duration of hospitalization, cost, and survival. RESULTS A total of 42 MM patients underwent ASCT. Of these, 26 patients and 16 patients underwent NC and CRYO stem cell collections, respectively. There was no difference in time to neutrophil engraftment (median 12 vs. 10.5 days, P=0.203) or platelet engraftment (median 14 vs. 12 days, P=0.809) between groups. The incidence of infusion reactions and duration of hospitalization were similar in both groups. The average cost of ASCT was 10% lower in the NC group. There was no difference in progression-free survival (median 16 vs. 22 months, P=0.701) or overall survival between NC and CRYO groups. CONCLUSIONS ASCT in MM using the NC preservation method is effective and safe compared to the CRYO method in both short-term and survival outcomes.

Autologous hematopoietic stem cell transplantation with inadequate stem cell dose in patients with non-Hodgkin lymphoma

Little is known regarding the outcome of lymphoma patients undergoing autologous hematopoietic stem cell transplantation (AHSCT) using inadequate hematopoietic stem cell (HSC) doses. Fifty-six patients were enrolled in the study, and the cohort was subdivided into two groups according to the infusion dose: < 1 × 10⁶/kg (poor HSC group) and 1-2 × 10⁶/kg (unfavorable HSC group). Compared with the unfavorable group, the poor HSC group had a longer median time to neutrophil (13 vs. 11 days, p = .007) and platelet engraftment (17 vs. 13 days, p = .024). CD34+ cell infusion dose of < 1 × 10⁶/kg was the only risk factor for neutrophil and platelet engraftment. The expected 3-year progression-free survival and overall survival rates for the whole cohort were 53% and 66%, and no statistical difference was observed between two groups. In conclusion, inadequate HSC infusion dose did not negatively impact AHSCT patient survival but significantly prolonged the time to hematopoietic engraftment.