Harvesting of autologous blood stem cells after a mobilising regimen with low-dose cyclophosphamide

Factors determining pbsc mobilization efficiency and nonmobilization following ICE with or without rituximab (R-ICE) salvage therapy for refractory or relapsed lymphoma prior to autologous transplantation

ICE/R-ICE (ifosfamide, carboplatin, and etoposide without or with rituximab) chemotherapy followed by autologous stem cell transplantation is an established regimen in refractory/relapsed lymphoma. Few studies have addressed which factors are important in determining peripheral blood stem cell (PBSC) mobilization efficiency or nonmobilization following ICE/R-ICE. Between 2004 and 2013, 88 patients with refractory/relapsed lymphoma who received ICE/R-ICE salvage-chemotherapy prior to granulocyte colony stimulating factor (G-CSF) stimulated PBSC mobilization at a single center were identified. Mobilization efficiency was assessed by time from ICE/R-ICE to day of harvest, duration of G-CSF use, days to peripheral blood (PB) CD34(+) ≥15/µL, PB CD34(+) number on harvest day, CD34(+) yield and nonmobilization rate. Median PB CD34(+) at harvest were 54/μL (7-524); median days to first apheresis was 15 (11-30); median harvested total CD34(+) were 5.46 × 10(6) /kg (0.96-44.36); 71 patients (80.7%) successfully mobilized; 20 (22.7%) patients were poor mobilizers; 14 (15.9%) patients were considered nonmobilizers with maximal PB CD34(+) <7/µL and did not proceed to apheresis. Six of 20 poor mobilizers were apheresed with PB CD34(+) 7-12/µL, 50% were successfully harvested. No differences were found between ICE and R-ICE regimens. Impaired mobilization efficiency was associated with age, remission status, >1 line of induction chemotherapy, four cycles ICE/R-ICE and grade 4 neutropenia. Prior bone marrow (BM) involvement was associated with nonmobilization. The majority of patients can be successfully mobilized with ICE/R-ICE. Prior BM involvement is associated with high rates of nonmobilization following ICE/R-ICE. Such patients may benefit from novel mobilization agents and/or alternative salvage regimens to ICE/R-ICE.

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.

Current status of stem cell mobilization

New advances in effective mobilization of peripheral blood stem cells have permitted a greater proportion of patients to benefit from autologous stem cell transplantation. In this review, the relative merits of peripheral blood and mobilized bone marrow are discussed. All available agents are reviewed. A critical assessment of the appropriate dosing and frequency of available growth factors is undertaken, and the most commonly used chemotherapy plus growth factor combinations are covered. Specific recommendations for patients who are poor mobilizers are dealt with including the role of plerixafor.

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

Increasing demand on the apheresis service makes efficient harvesting of peripheral blood stem cells (PBSCs) essential. A total of 168 adult patients with haematological malignancy were primed using low-moderate dose cyclophosphamide (1.5-3 g/m(2)) with G-CSF 5-10 microg/kg per day. Harvesting was booked and peripheral blood (PB) counts first checked between 6 and 10 days post-priming. One hundred and thirty (77%) patients harvested successfully (total harvest yield > or =2 x 10(6) CD34(+)/kg) and the median PBSC collection per procedure was 2.18 x 10(6)/kg (range 0.1-14.5). Only more lines of prior chemotherapy predicted failure to harvest in multivariate analysis (P=0.003). The PB CD34(+) cell count correlated significantly with harvest yield (r=0.8448, P<0.0001). A PB CD34(+) count > or =10/microl predicted a collection of > or =2 x 10(6)/kg (positive-predictive value of 61%, negative-predictive-value 100%). Patients first attending day 9 required significantly fewer visits to achieve a successful harvest than those first attending days 6-8 without increasing the risk of failure. No significant difference in failure rates, number of days attending and total harvest yield was found between days 9 and 10 attendees. Collection from day 9 may however enable higher target yields to be achieved. PB CD34(+) count monitoring should commence and harvesting booked from day 9 to optimize both the harvest and the efficiency of the PBSC harvesting service.

The Effect of Repeated Administration of Cyclophosphamide on Cytochrome P450 2B in Rats

PURPOSE

The prodrug cyclophosphamide (CPA) is activated by cytochrome P450 (CYP) enzymes. CPA is one of the corner stones in all cancer treatment. We have studied the effect of repeated doses of CPA given at different time intervals on the mRNA, protein levels, and enzyme activity of CYPs in rats.

EXPERIMENTAL DESIGN

Two groups of animals (A-75 and A-150) were treated with four doses of CPA (75 and 150 mg/kg, respectively) at short time intervals (6 h). The third group of animals (B-150) was treated with 150 mg/kg at 24-h intervals. Three animals were killed 30 min after administration, and three animals immediately before the next dose.

RESULTS

CYP2B1 and CYP2B2 mRNAs were significantly induced at 6 h after each dose in group A-75 (maximum of 2100-fold and 60-fold after the third dose, respectively), whereas the mRNA levels measured at 6 h postadministration in group A-150 were 1,490-fold and 36-fold after the second dose. In group B-150, no significant induction of mRNA levels was observed. CYP2B1 and CYP2B2 protein levels also increased with increased mRNAs. Plasma levels of 4-hydroxy-CPA measured at 30 min after dose correlated well with the increase in protein levels.

CONCLUSION

Up-regulation of CYP2B mRNA, with a concomitant increase in protein expression and activity, were observed after repeated administration of low doses of CPA compared with that found using higher doses, possibly due to toxicity counteracting induction. These results may help in designing more effective dosing schedules for CPA.

Mobilization, harvesting and selection of peripheral blood stem cells in patients with autoimmune diseases undergoing autologous hematopoietic stem cell transplantation

Peripheral blood stem cells (PBSC) were mobilized in 130 patients with autoimmune diseases undergoing autologous hematopoietic stem cell transplantation using cyclophosphamide 2 g/m(2) and either granulocyte colony-stimulating factor (G-CSF) 5 mcg/kg/day (for systemic lupus erythematosus (SLE) and secondary progressive multiple sclerosis, SPMS) or G-CSF 10 mcg/kg/day (for relapsing remitting multiple sclerosis (RRMS), Crohn's disease (CD), systemic sclerosis (SSc), and other immune-mediated disorders). Mobilization-related mortality was 0.8% (one of 130) secondary to infection. Circulating peripheral blood (PB) CD34(+) cells/microl differed significantly by disease. Collected CD34(+) cells/kg/apheresis and overall collection efficiency was significantly better using Spectra apheresis device compared to the Fenwall CS3000 instrument. Patients with SLE and RRMS achieved the lowest and the highest CD34(+) cell yields, respectively. Ex vivo CD34(+) cell selection employing Isolex 300iv2.5 apparatus was significantly more efficient compared to CEPRATE CS device. Circulating PB CD34(+) cells/microl correlated positively with initial CD34(+) cells/kg/apheresis and enriched product CD34(+) cells/kg. Mean WBC and platelet engraftment (ANC>0.5 x 10(9)/l and platelet count >20 x 10(9)/l) occurred on days 9 and 11, respectively. Infused CD34(+) cell/kg dose showed significant direct correlation with faster white blood cell (WBC) and platelet engraftment. When adjusted for CD34(+) cell/kg dose, patients treated with a myeloablative regimen had significantly slower WBC and platelet recovery compared to non-myeloablative regimens.

ESHAP+fixed dose G-CSF as autologous peripheral blood stem cell mobilization regimen in patients with relapsed or refractory diffuse large cell and Hodgkin's lymphoma: a single institution result of 127 patients

From 1996 to November 2004, 131 consecutive patients with relapsed or refractory diffuse large cell lymphoma (DLCL) and Hodgkin's lymphoma (HD) received ESHAP as mobilization chemotherapy before autologous peripheral blood stem cell transplant (ASCT). Patients received fixed dose G-CSF 300 microg SC bid starting 24-36 h after finishing mobilizing ESHAP. In all, four patients failed mobilization and are excluded. Characteristics of 127 patients: 68 males: 59 females. DLCL 49: HD 78. Initial stage I:II:III:IV:unknown was 15:34:33:42:3. Median age at ASCT 26 years. Median prior chemotherapy cycles were six [<6 (17 patients), 6-8 (90 patients), >8 (20 patients)]. Median ESHAP cycle used as mobilizer was third. Patients required 1, 2, 3, 4 apheresis were 93:25:8:1. Median total CD34+ cells/kg collected were 6.9 x 10(6) (DLCL 5.17 x 10(6) and HD 7.6 x 10(6)), patients weighing < or = 70 kg (93 patients) 6.54 x 10(6) and >70 kg (34 patients) 7.44 x 10(6) (P = 0.59), one apheresis (93 patients) 8.6 x 10(6)/kg and >1 apheresis (34 patients) 4.5 x 10(6) (P = 0.001). We conclude that ESHAP and G-CSF 300 microg SC bid is an effective mobilizing regimen even in patients >70 kg and most patients require only 1-2 apheresis.