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Abstract Background According to the different sensitivity of their bone marrow CD34+ cells to in vitro treatment with Etoposide or Mafosfamide, Acute Myeloid Leukaemia (AML) patients in apparent complete remission (CR) after chemotherapy induction may be classified into three groups: (i) normally responsive; (ii) chemoresistant; (iii) highly chemosensitive. This inversely correlates with in vivo CD34+ mobilization and, interestingly, also with the prognosis of the disease: patients showing a good mobilizing activity are resistant to chemotherapy and subject to significantly higher rates of Minimal Residual Disease (MRD) and relapse than the others. Based on its known role in patients' response to chemotherapy, we hypothesized an involvement of the Apoptotic Machinery (AM) in these phenotypic features. Methods To investigate the molecular bases of the differential chemosensitivity of bone marrow hematopoietic stem cells (HSC) in CR AML patients, and the relationship between chemosensitivity, mobilizing activity and relapse rates, we analyzed their AM expression profile by performing Real Time RT-PCR of 84 AM genes in CD34+ pools from the two extreme classes of patients (i.e., chemoresistant and highly chemosensitive), and compared them with normal controls. Results The AM expression profiles of patients highlighted features that could satisfactorily explain their in vitro chemoresponsive phenotype: specifically, in chemoresistant patients we detected up regulation of antiapoptotic BIRC genes and down regulation of proapoptotic APAF1, FAS, FASL, TNFRSF25. Interestingly, our analysis of the AM network showed that the dysregulated genes in these patients are characterized by high network centrality (i.e., high values of betweenness, closeness, radiality, stress) and high involvement in drug response. Conclusions AM genes represent critical nodes for the proper execution of cell death following pharmacological induction in patients. We propose that their dysregulation (either due to inborn or de novo genomic mutations selected by treatment) could cause a relapse in apparent CR AML patients. Based on this, AM profiling before chemotherapy and transplantation could identify patients with a predisposing genotype to MRD and relapse: accordingly, they should undergo a different, specifically tailored, therapeutic regimen and should be carefully checked during the post-treatment period.

We here report final results of a phase II/III prospective study that evaluated in Multiple Myeloma the use of on-demand plerixafor (PLX) added to mobilizing chemotherapy for patients showing predictive signs of mobilization failure. A total of 111 patients with MM were registered, all received cyclophosphamide 4 g/m2and granulocyte colony-stimulating factor (G-CSF). Overall, a successful CD34+ cell mobilization was achieved in 97.2% (108/111) of patients. Minimum harvest (≥2.0 × 106CD34+ cells/kg) was achieved in 97.2% (108/111) and optimal harvest success (≥4.0 × 106CD34+ cells/kg) was achieved in 84.6% (94/111). Multivariate analysis showed that patients who received on-demand PLX treatment had significantly higher likelihoods of successfully achieving both the minimal (p = .006) and optimal harvest (p = .05) in respect to a historical control group mobilized without any PLX. The incremental cost-effectiveness ratio, for each 1% increase in probability of achieving a successful minimal harvest, was€40.6 per patient. [ABSTRACT FROM AUTHOR]

Background: According to the different sensitivity of their bone marrow CD34+ cells to in vitro treatment with Etoposide or Mafosfamide, Acute Myeloid Leukaemia (AML) patients in apparent complete remission (CR) after chemotherapy induction may be classified into three groups: (i) normally responsive; (ii) chemoresistant; (iii) highly chemosensitive. This inversely correlates with in vivo CD34+ mobilization and, interestingly, also with the prognosis of the disease: patients showing a good mobilizing activity are resistant to chemotherapy and subject to significantly higher rates of Minimal Residual Disease (MRD) and relapse than the others. Based on its known role in patients' response to chemotherapy, we hypothesized an involvement of the Apoptotic Machinery (AM) in these phenotypic features. Methods: To investigate the molecular bases of the differential chemosensitivity of bone marrow hematopoietic stem cells (HSC) in CR AML patients, and the relationship between chemosensitivity, mobilizing activity and relapse rates, we analyzed their AM expression profile by performing Real Time RT-PCR of 84 AM genes in CD34+ pools from the two extreme classes of patients (i.e., chemoresistant and highly chemosensitive), and compared them with normal controls. Results: The AM expression profiles of patients highlighted features that could satisfactorily explain their in vitro chemoresponsive phenotype: specifically, in chemoresistant patients we detected up regulation of antiapoptotic BIRC genes and down regulation of proapoptotic APAF1, FAS, FASL, TNFRSF25. Interestingly, our analysis of the AM network showed that the dysregulated genes in these patients are characterized by high network centrality (i.e., high values of betweenness, closeness, radiality, stress) and high involvement in drug response. Conclusions: AM genes represent critical nodes for the proper execution of cell death following pharmacological induction in patients. We propose that their dysregulation (either due to inborn or de novo genomic mutations selected by treatment) could cause a relapse in apparent CR AML patients. Based on this, AM profiling before chemotherapy and transplantation could identify patients with a predisposing genotype to MRD and relapse: accordingly, they should undergo a different, specifically tailored, therapeutic regimen and should be carefully checked during the post-treatment period. [ABSTRACT FROM AUTHOR]

We designed intermediate dose etoposide + G-CSF 16 µg/kg as a Peripheral Blood Stem Cell (PBSC) mobilization schedule suitable for outpatient administration. Forty-one Lymphoma patients received intermediate dose etoposide (200 mg/m2 i.v. day +1, +2, +3) +G-CSF 16 µg/kg/day. Results of PBSC mobilization in these patients were compared with those of a group of 37 lymphoma patients mobilized using cyclophosphamide (CTX) at dosage of 4 g/m2 + G-CSF 10 µg/kg/die. Mean peak of CD34+ cells achieved in P.B. and total CD34+ cells harvested were higher in patients mobilized with intermediate dose etoposide (p = 0.003 and p = 0.004, respectively). After transplantation recovery of polymorphonucleate neutrophils (PMN) > 0.5 × 109/L did not differ significantly between groups: 11.7 days in intermediate dose etoposide group and 11.5 days in CTX group (p = 0.7). Intermediate dose etoposide + G-CSF 16 µg/kg resulted in a maximum length of neutropenia (PMN < 0.5 × 109/L) of 2 days and neutropenic fever was registered during only 3/41 courses (7.3%). Intermediate dose etoposide + G-CSF 16 µg/kg is a highly effective mobilizing therapy, further, it has the advantage of low hematologic toxicity and can be easily administered as outpatient treatment. [ABSTRACT FROM AUTHOR]

A high number of CD34+ cells in the peripheral blood during mobilization in patients with acute myeloid leukemia (AML) in complete remission (CR) is associated with a high relapse rate. The variability in chemoresistance of normal bone marrow precursors has been hypothesized as explanation for the variable CD34 mobilization in AML. In 37 patients with AML in CR, we determined the chemosensitivity of bone marrow clonogenic precursors to maphosphamide and etoposide, which was then correlated with the degree of CD34+ mobilization. In an enlarged set of 49 patients, we also studied the importance of chemosensitivity of marrow precursors for disease-free survival and relapse incidence. Significant correlations were demonstrated between the peak number of CD34+ cells and residual growth of colony-forming unit granulocyte-macrophage (CFU-GM) after maphosphamide (R = 0.550; p = 0.0003) and after etoposide (R = 0.793; p = 0.0003). It was possible to identify three groups of AML patients based on chemosensitivity. The mean CD34+ peak was 33 × 106/L in the hyperchemosensitive group, 141 × 106/L in the normochemosensitive (p = 0.03), and 379 × 106/L in the chemoresistant group (p = 0.002). Failed CD34+ mobilization was observed in 72% of the hyperchemosensitive group, 23% of the normochemosensitive group, and 0% of the chemoresistant group (p = 0.001). Hyperchemosensitivity of CFU-GM, together with a low platelet count, were independent factors important in the failure of CD34+ cell mobilization. A disease-free survival significantly inferior to that of all other patients was associated with chemoresistance of CFU-GM (log rank, p = 0.030) and with chemoresistance of burst-forming unit erythroid (BFU-E) (log rank, p = 0.033). Chemoresistance of CFU-GM (p = 0.048) and BFU-E (p = 0.017) was also associated with increase relapse incidence. Nonleukemic nature of these precursors was demonstrated studying minimal residual disease from single colony cells. In conclusion, we found that hyperchemosensitivity of normal nonleukemic CFU-GM is associated with a high risk of CD34+ cell mobilization failure, while a chemoresistant pattern in CFU-GM and BFU-E is associated with poor disease-free survival and increased cumulative incidence of relapse. [Copyright &y& Elsevier]