Clinical impact of ex vivo differentiated myeloid precursors after high-dose chemotherapy and peripheral blood progenitor cell rescue

Abstract

Summary:The infusion of ex vivo differentiated myeloid precursors may be able to shorten the period of obligatory neutropenia after high-dose chemotherapy and peripheral blood progenitor cell rescue by providing cells capable of differentiating to mature neutrophils within days of infusion. To test this hypothesis, 21 female patients with metastatic breast cancer underwent progenitor cell mobilization with cyclophosphamide, etoposide and G-CSF. CD34+ cells from one to two leukapheresis products were isolated and placed in suspension culture with a serum-free growth medium supplemented with PIXY321. The cultures were maintained for 12 days with subcultures initiated on day 7. The remaining leukapheresis products were cryopreserved in an unmanipulated state. Forty-eight hours after completing high-dose cyclophosphamide, thiotepa and carboplatin, the cryopreserved progenitors were infused, followed 1 to 24 h later by infusion of the differentiated myeloid precursors. In one patient, the cultured cells were labeled with Indium-111 with nuclear imaging performed up to 48 h post infusion. The differentiated myeloid precursors were suitable for infusion in 17 of the patients with a median 13-fold expansion of total nucleated cells. A range of 5.6 to 1066 × 10 7 nucleated cells were infused. Morphologically the cells were predominantly of myeloid lineage (63%) with a median 41% of the cells expressing CD15. No untoward effects were noted with the infusion of the cultured cells. The median days to neutrophil and platelet recovery were 8 and 10 days, respectively. There was a significant relationship (r = 0.67, P = 0.007) between the dose of differentiated myeloid precursors (CD15 + cells) and the depth and duration of neutropenia; a similar relationship, however, was also observed with the dose of cryopreserved CD34 + cells. After infusion of the radiolabeled myeloid precursors, a pattern of distribution similar to radio-labeled granulocytes was noted with uptake detected initially in the lungs and subsequently the reticulo-endothelial system. The impact of differentiated myeloid precursors on neutropenia as an adjunct to high-dose chemotherapy and peripheral blood pro-

Large-scale ex vivo generation of human neutrophils from cord blood CD34+ cells

“…Besides, CD66b + UCB neutrophils are presented in the peripheral blood of recipient mice much longer than peripheral blood neutrophils, strongly suggesting that the ex vivo generated neutrophils (and progenitors) can further mature in vivo . To date, a few research groups have investigated ex vivo expansion of neutrophil progenitors from HSCs [58–60], and in two such studies, expanded cells have been used clinically for providing autologous HSCs. In the current study, we have injected cryopreserved neutrophil progenitor cells (day 9 culture) into neutropenia NOD/SCID mice via the tail vein.…”

Improved haematopoietic recovery following transplantation with ex vivo‐expanded mobilized blood cells*

“…Other studies have attempted to examine the impact of ex vivo expansion on haematopoietic recovery. These studies have utilized various combinations of cytokines, used different methods of cell expansion and investigated patients with various disease types (Reiffers et al , 1999; Williams et al , 1996; McNiece et al , 2000; Paquette et al , 2000; Zimmerman et al , 2000; Engelhardt et al , 2001; Devine et al , 2003; Reichle et al , 2003). The studies by Reiffers et al (1999), Paquette et al (2000) and McNiece et al (2000), all utilized the same cytokine combination as in our study and they too demonstrated an impact on neutrophil recovery; however interpretation of the data is hampered because their comparators were historical controls.…”

“…Indeed, preclinical data indicates that both myeloid and megakaryocytic progenitors can be expanded in static culture systems with various growth factor combinations (Haylock et al , 1992; To et al , 1997). To date, several clinical ex vivo expansion studies based on this rationale have been performed, using a variety of culture systems and cytokine combinations (Reiffers et al , 1999; Williams et al , 1996; McNiece et al , 2000; Paquette et al , 2000; Zimmerman et al , 2000; Engelhardt et al , 2001; Reichle et al , 2003). Although a number of these studies have demonstrated a positive impact on myeloid cell recovery (with one demonstrating a modest impact on platelet recovery; Paquette et al , 2000) all except one study (Reichle et al , 2003) have utilized historical control patients.…”

Ex vivo Expanded Megakaryocytes for Supportive Care of Breast Cancer Patients

“…There was a significant correlation between the time to neutrophil recovery and the total expanded nucleated cells/kg, but not the CD34+ cell dose/kg. Zimmerman and colleagues expanded CD34+ selected PBPC in the presence of PIXY321 in 21 women with metastatic breast cancer, infusing the expanded product as a supplement to the unselected PBPC autograft [9]. They observed no toxicity associated with the EVE-PBPC infusion and noted a significant inverse relationship between the dose of differentiated myeloid precursors and the depth and duration of neutropenia.…”

“…An increasing number of clinical trials investigating the administration of EVE PBPC following high-dose chemotherapy are being reported, and to date, intravenous administration of EVE hematopoietic progenitors, cultured in the presence of a wide variety of cytokine combinations, has not been associated with toxicity [3][4][5][6][7][8][9][10]. Hematopoietic progenitors may be expanded ex vivo, while retaining their capacity to reconstitute hematopoiesis [7].…”