Autologous transplantation of chemotherapy-purged PBSC collections from high-risk leukemia patients: a pilot study

Abstract

We have recently demonstrated that the combination of the alkylating agent nitrogen mustard (NM) and etoposide (VP-16) is capable of eliminating, ex vivo, leukemic cells contaminating PBSC collections and this is associated with a significant recovery of primitive and committed hematopoietic progenitor cells. Based on these data a pilot study on autologous transplantation of NM/VP-16 purged PBSC for high-risk leukemic patients was recently initiated. Twelve patients (seven females and five males) with a median age of 46 years (range 18-57) have been treated. Two patients had acute myeloblastic leukemia (AML) resistant to conventional induction treatment, four patients had secondary AML in I complete remission (CR), one patient was in II CR after failing a previous autologous BM transplantation, while two additional AML individuals were in I CR achieved after three or more cycles of induction treatment. Two patients with high-risk acute lymphoblastic leukemia (ALL) in I CR and one patient with mantle cell lymphoma and leukemic dissemination were also included. Eight patients showed karyotypic abnormalities associated with a poor clinical outcome. The mobilizing regimens included cytosine arabinoside and mitoxantrone with (n = 6) or without fludarabine (n = 3) followed by subcutaneous administration of G-CSF (5 microg/kg/day until the completion of PBSC collection) and G-CSF alone (n = 3) (15 microg/kg/day). A median of two aphereses (range 1-3) allowed the collection of 7.2 x 10(8) TNC/kg (range 3.4-11.5), 5 x 10(6) CD34+ cells/kg (range 2.1-15.3) and 9.2 x 10(4) CFU-GM/kg (0.3-236). PBSC were treated with a constant dose of 20 microg of VP-16/ml and a median individual-adjusted dose (survival < or = 5% of steady-state BM CFU-GM) of NM of 0.7 microg/ml (range 0.25-1.25). Eleven patients were reinfused after busulfan (16 mg/kg) and Cy (120 mg/kg) conditioning with a median residual dose of 0.3 x 10(4) CFU-GM/kg (0-11.5). The median time to neutrophil engraftment (>0.5 x 10(9)/l) for evaluable patients was 25 days (range 12-59); the median time to platelet transfusion independence (>20 and >50 x 10(9)/l) was 40 days (18-95) and 69 days (29-235), respectively. Hospital discharge occurred at a median of 25 days (18-58) after stem cell reinfusion. Four individuals are alive in CR (n = 3) or with residual nodal disease (n = 1 lymphoma patient) with a follow-up of 32, 26, 3 and 14 months, respectively. Seven patients died due to disease progression or relapse (n = 5) or extrahematological transplant toxicity (n = 2). Our data suggest that pharmacological purging of leukapheresis collections of leukemic patients at high-risk of relapse is feasible and ex vivo treated cells reconstitute autologous hematopoiesis.

Double reinforcement with fludarabine/high-dose cytarabine enhances the impact of autologous stem cell transplantation in acute myeloid leukemia patients

“…6,20 Progenitor cell apheresis was begun after an absolute count of 10 CD34 + cells/ l was achieved during the recovery phase after consolidation therapy. As already reported, 17,18,21 circulating stem cells were collected by using either a Fenwal CS3000 continuous flow blood cell separator (Baxter, Rome, Italy) or a Cobe Spectra separator (Cobe BCT, Lakewood, CO, USA) to obtain a minimum yield of 2 × 10 6 CD34 + cells/kg. Non-mobilizing patients underwent bone marrow harvest, as previously reported.…”

“…From May 1994, all patients received G-CSF (10 g/kg/day), to mobilize peripheral blood progenitor cells. 17,18 When mobilization was insufficient (Ͻ10 CD34 + cells/ l), bone marrow was subsequently harvested in steady-state conditions.…”

“…Non-mobilizing patients underwent bone marrow harvest, as previously reported. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The final apheresis product was concentrated and cryopreserved as described. When applicable, cytogenetic and molecular analyses were performed in order to confirm CR.…”

Fludarabine‐containing regimens severely impair peripheral blood stem cells mobilization and collection in acute myeloid leukaemia patients

“…The relative advantages and disadvantages of autologous bone marrow transplantation (ABMT) or peripheral blood stem cell (PBSC) transplantation are still under evaluation. PBSC transplantation performed after standard induction regimens appears superior to ABMT as regards the recovery times of polymorphonuclear and platelet counts (Korbling et al , 1991; To et al , 1992; Sanz et al , 1993; Demirer et al , 1996; Schiller et al , 1997; Reiffers et al , 1992), but concerns have been raised regarding an increased potential for relapse following the procedure (Korbling et al , 1991; Sanz et al , 1993; Laporte et al , 1997; Mehta et al , 1995; Motta et al , 1997; Lemoli et al , 1999). Thus, intensification of induction/consolidation chemotherapy has been proposed in order to determine in vivo purging prior to PBSC (Mehta et al , 1995).…”

NK-cell purging of leukemia: superior antitumor effects of NK cells H2 allogeneic to the tumor and augmentation with inhibitory receptor blockade

“…46,47 Different physical, clinical, and immunologic means have been used to purge the contaminating tumor cells ex vivo, including the use of activated autologous NK cells to overcome relapse. [48][49][50][51][52] In our previous report investigating the possibility of syngeneic NK cells as purging agents in a murine leukemia model, we demonstrated that blocking inhibitory receptors specific for class I on a subset of syngeneic NK cells during ex vivo purging of C1498 murine leukemia contaminating the bone marrow graft significantly increased the extent of tumor cell elimination by syngeneic NK cells. 53 We also demonstrated that transplanting tumorcontaminating BMCs purged with syngeneic NK cells with inhibitory receptor blockade resulted in an increased proportion of long-term survivors without affecting hematopoietic cell recovery.…”