4-Hydroperoxycyclophosphamide purging of breast cancer from the mononuclear cell fraction of bone marrow in patients receiving high-dose chemotherapy and autologous marrow support: a phase I trial.

Abstract

We designed an ex vivo bone marrow treatment for breast cancer patients receiving high-dose chemotherapy and autologous bone marrow support (ABMS), using 4-hydroperoxycyclophosphamide (4-HC), an active derivative of cyclophosphamide with known activity against breast cancer. This phase I bone marrow purging trial used ficoll-separated mononuclear cells (MNC) (devoid of granulocytes and RBCs), as opposed to the buffy coat. Twenty-five patients with metastatic breast cancer were studied. Patients received three cycles of the Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH), fluorouracil, and methotrexate (Duke AFM) regimen, followed by marrow harvest. An MNC fraction of marrow was prepared and treated with 4-HC in concentrations of 20 micrograms/mL (four patients), 40 micrograms/mL (four patients), 60 micrograms/mL (nine patients), or 80 micrograms/mL (eight patients) and cryopreserved. Patients then received high-dose systemic cyclophosphamide, cisplatin, and carmustine, followed by infusion of the purged marrow. The study end point was marrow engraftment, defined as WBC count greater than 1,000 cells per microliter. At the first three dose levels (20, 40, and 60 micrograms/mL 4-HC), there was no significant delay in time to engraftment (19, 20, and 23 days, respectively) compared with the unpurged historical controls (17 days). At 80 micrograms/mL, engraftment was significantly delayed compared with the lower concentrations (P = .027), and further escalation of 4-HC was not attempted. A significant correlation was observed between the time of leukocyte engraftment and the 4-HC concentration (P = .017). With a methylcellulose-based tissue culture assay, we demonstrated a statistically significant correlation between the colony-forming unit-granulocyte-macrophage (CFU-GM) content in the purged marrow and the days to engraftment. Ninety-five percent of patients responded clinically to the entire program, 55% of them completely. Longer follow-up is required to assess the ultimate benefit of intensive therapy on long-term survival.

Purging and haemopoietic progenitor cell selection by CD34+ cell separation

“…In a subsequent clinical phase 1 trial, a significant delay in leukocyte recovery could be correlated with the mafosfamide concentration used for tumour cell purging. 24 The combination of mafosfamide incubation with immunotoxin treatment was examined by O'Briant et al 25 in an in vitro study. They described 2.2-5.4 log tumour cell reduction from a 1:10 breast cancer cell dilution in irradiated marrow cells.…”

High-dose chemotherapy in patients with breast cancer: evaluation of infusing peripheral blood stem cells containing occult tumor cells

“…3,4,[32][33][34] However, there have been no prospective randomized trials to determine if these techniques diminish the probability of relapse or progression after HDC and BM or PBSC infusion. Randomized clinical trials designed to evaluate an effect of purging on relapse or progression will be difficult, if not impossible, to perform because available HDC regimens do not eradicate endogenous disease in the majority of patients with stage IV breast cancer.…”

A novel triple purge strategy for eliminating chronic myelogenous leukemia (CML) cells from autografts

“…[13][14][15][16] In more recent preclinical studies the combination of imatinib and mafosfamide has been shown to exert impressive synergistic antitumor activity against CML cells. 17 This stimulated our interest in using this drug combination in an ex vivo autograft-purging regimen.…”