An analysis of the optimal timing of peripheral blood stem cell harvesting following priming with cyclophosphamide and G-CSF

Comparison of two apheresis systems for autologous stem cell collections in pediatric oncology patients

BACKGROUND

Peripheral stem cell collections can be challenging in the pediatric population and respective experience is limited. Since February 2015 our institution is utilizing the new Spectra Optia (Optia) apheresis device, which has replaced the former COBE Spectra (COBE) device. As a quality initiative we collected and compared collection efficiency (CE2) and other collection variables between the two devices.

STUDY DESIGN AND METHODS

In this retrospective study we collected and compared clinical, laboratory, and technical collection data from stem cell collection procedures done with the Optia and COBE devices. The collected data included patient demographics, precollection peripheral CD34+ cell counts, total CD34+ cells collected, complete blood count, electrolytes before and after collection, side effects attributed to the collection, total blood volumes processed (TBVs), collection times, and calculated CE2 and collection ratios.

RESULTS

Forty-one collection procedures performed on 29 pediatric patients with the Optia device were compared to 41 collections performed on 27 patients with the COBE device. The TBVs through the Optia device were significantly smaller than the COBE (3.9 ± 0.2 × TBV vs. 5.5 ± 0.1 × TBV, respectively; p < 0.001), requiring significantly less anticoagulant and providing similar amounts of stem cells while collection times were significantly shorter (mean, 238 ± 9 min vs. 264 ± 9 min, respectively; p < 0.05). Collections on the Optia caused significantly smaller reductions of plasma calcium and magnesium. No significant side effects attributed to the procedure were noted.

CONCLUSION

Stem cell apheresis with the Optia device in children is safe and feasible with smaller blood volumes with shorter collection times.

Peripheral stem cell harvest using regular chemotherapy schedules in childhood cancer

Prediction of the best moment for the harvest of PBSCs after standard chemotherapy followed by filgrastim in children with cancer is difficult. We retrospectively analyzed the moment of harvesting of 152 procedures in 94 patients. The start of apheresis was guided by WBC count and CD34+ cell measurement in peripheral blood. We defined the first day of filgrastim administration, after completion of mobilizing chemotherapy, as day 1. Median time to harvest in different subgroups is as follows: neuroblastoma 11 days (range, 6-29 days), Ewing's sarcoma nine days (range, 7-15 days), brain tumor 10 days (range, 7-15 days), relapsed Wilms' tumor 16 days (range, 9-20 days), and extracranial GCT seven days (range, 6-14 days). Patients harvested after cyclophosphamide priming (time to harvest within a range of 8-9 days) were analyzed as a separate group. The optimal moment for harvesting in different types of tumors was highly variable, although most consistent in patients diagnosed with Ewing's sarcoma or brain tumors and after cyclophosphamide priming.

Comparison of high-dose CY and growth factor with growth factor alone for mobilization of stem cells for transplantation in patients with multiple myeloma

We retrospectively analyzed outcomes of 716 patients with multiple myeloma who were mobilized using CY and growth factor (n=370) or growth factor alone (n=346) before SCT. Patients receiving CY had higher stem cell yields than the growth factor only group (median number of apheresis sessions needed to achieve stem cell collection goals, two vs four sessions, respectively (P=0.001)). However, patients treated with CY required more time for engraftment of platelets and neutrophils (P<0.001 for both). For patients receiving CY, 75% achieved engraftment (defined as a platelet count of 50 x 10(9)/l) by day 39, whereas 75% of patients not receiving CY achieved engraftment by day 18. Similar results were observed for neutrophil engraftment. These differences did not affect the duration of hospitalization, but patients treated with CY had a higher incidence of post transplant nonstaphylococcal bacteremia. For CY-mobilized patients, considerably faster platelet engraftment (5 fewer days) resulted if stem cell reinfusion occurred more than 30 days after the first apheresis session. Our data suggested that CY damaged the microenvironment and slowed engraftment. By lengthening the period between the completion of apheresis and stem cell reinfusion, the microenvironment may recover and result in faster engraftment.

An algorithm based on peripheral CD34+ cells and hemoglobin concentration provides a better optimization of apheresis than the application of a fixed CD34 threshold

BACKGROUND

Optimization of peripheral blood stem cell (PBSC) collection for autologous bone marrow transplantation is necessary for a good standard of care and cost-effectiveness. An algorithm was validated for prediction of the day of maximum peripheral CD34+ cell concentration after mobilization chemotherapy (Day(CD34peak)).

STUDY DESIGN AND METHODS

This study compared mobilization and collection variables of a cohort of patients where apheresis was started at the Day(CD34peak) predicted by the algorithm with a patient group where PBSCs were collected when PB CD34+ cell concentration reached 10 per microL per day (Day(CD34threshold)). Day(CD34peak) was calculated according to the equation Day(CD34peak) = -0.41 x Hb(D0) + 0.99 x Day(CD34threshold) + 7.8 (with Hb(D0) representing the hemoglobin value on Day 0).

RESULTS

The mean number of apheresis procedures per patient based on the Day(CD34threshold) was 1.74, but decreased to 1.35 when applying the new method (Day(CD34peak)). For lymphomas, the mean number of apheresis procedures decreased from 1.98 to 1.47 (p = 0.03), while in patients with multiple myeloma it did not change significantly (1.23 and 1.26, respectively). Age and primary disease influenced the number of apheresis procedures needed to achieve the collection target.

CONCLUSION

The application of our algorithm can lower the number of apheresis procedures by improving the timing, especially in patients suffering from malignant lymphomas with a poor marrow potential after several chemotherapy lines.

Stem cell harvesting protocol research in autologous transplantation setting: Large volume vs. conventional cytapheresis

Background/Aim. The use of peripheral blood as a source of hematopoietic stem cells (SCs) is progressively increasing and has nearly supplanted bone marrow transplantation. Interpatient variability in the degree and kinetics of SC mobilization into peripheral blood is an expected event after conventional chemotherapy-based treatment, followed by sequential administration of recombinant granulocyte-colony- stimulating factor (rHu-CSF). In this study, specific factors associated with the application of two different SC-harvesting approaches, including the use of large volume leukapheresis (LVL) vs. repetitive conventional apheresis (RCA), were analyzed. The basic goal of the study was to evaluate the influence of apheresis protocol (collection timing, processed blood volume and cell yield) upon the clinical outcome of transplantation. Methods. Results obtained by LVL (76 pts) and RCA (20 pts - control group) were compared. The SC mobilizing regimen used was cyclophosphamide (4-7 g/m2) or polychemotherapy and rHuG-CSF 10-16 ?g/kg of body mess (bm) per day. Cell harvesting was performed using COBE-Spectra (Caridian-BCT, USA). The volume of processed blood in LVL setting was ? 3.5 - fold of the patient's circulating blood quantity (ranged from 12.7 to 37.8 l). All patients tolerated well the use of intensive treatment, without any side or adverse effects. Our original controlled-rate cryopreservation was carried out with 10% dimethyl sulfoxide (DMSO) using Planer R203/200R or Planer 560-16 equipments (Planer Products Ltd, UK). Total nucleated cell (NC) and mononuclear cell (MNC) counts were examined by flow cytometry (Advia-2120 Bayer, Germany; Technicon H-3 System, USA). The CD34+ cell surface antigen was investigated by the EPICS XL-MCL device (Coulter, Germany). Results. Performing LVL-apheresis, high-level MNC and CD34+ cell yields (7.6?4.6 ? 108/kg bm and 11.8?6.5 ? 106/kg bm, respectively) were obtained. As a result, rapid hematopoietic reconstitution ("graft-healing") - on the 9.4th and 12.4th day for granulocytes and platelets, respectively was achieved. Using repetitive conventional apheresis (2-3 procedures), the total MNC count was high (8.2?7.0 ? 108/kg bm), but the total CD34+ yield was lower 10.8?9.9 due to inferior CD34+ vs. MNC ratio. Conclusion. The results obtained suggest that well-timed LVL-apheresis increased SC-yield in cell harvest, resulting in faster bone marrow repopulation and hematological reconstitution, as well as better overall clinical outcome of transplantation. These results necessitate additional examinations of CD34+ subsets ratio in cell harvest.