Hematopoietic stem cell mobilization with the reversible CXCR4 receptor inhibitor plerixafor (AMD3100)-Polish compassionate use experience

Recent developments in the field of targeted therapy have led to the discovery of a new drug, plerixafor, that is a specific inhibitor of the CXCR4 receptor. Plerixafor acts in concert with granulocyte colony-stimulating factor (G-CSF) to increase the number of stem cells circulating in the peripheral blood (PB). Therefore, it has been applied in the field of hematopoietic stem cell mobilization. We analyzed retrospectively data regarding stem cell mobilization with plerixafor in a cohort of 61 patients suffering from multiple myeloma (N = 23), non-Hodgkin’s lymphoma (N = 20), or Hodgkin’s lymphoma (N = 18). At least one previous mobilization attempt had failed in 83.6% of these patients, whereas 16.4% were predicted to be poor mobilizers. The median number of CD34+ cells in the PB after the first administration of plerixafor was 22/μL (range of 0–121). In total, 85.2% of the patients proceeded to cell collection, and a median of two (range of 0–4) aphereses were performed. A minimum of 2.0 × 10⁶ CD34+ cells per kilogram of the patient’s body weight (cells/kg b.w.) was collected from 65.6% of patients, and the median number of cells collected was 2.67 × 10⁶ CD34+ cells/kg b.w. (0–8.0). Of the patients, 55.7% had already undergone autologous stem cell transplantation, and the median time to neutrophil and platelet reconstitution was 12 and 14 days, respectively. Cases of late graft failure were not observed. We identified the diagnosis of non-Hodgkin’s lymphoma and previous radiotherapy as independent factors that contributed to failure of mobilization. The current report demonstrates the satisfactory efficacy of plerixafor plus G-CSF for stem cell mobilization in heavily pre-treated poor or predicted poor mobilizers.

Booster of plerixafor can be successfully used in addition to chemotherapy-based regimen to rescue stem cell mobilization failure

BACKGROUND

Autologous stem cell transplantation (autoSCT) is currently considered one of the standard approaches in the treatment of patients suffering from multiple myeloma and recurrent or relapsed lymphomas. Unfortunately, a significant proportion of those patients fail to mobilize minimum CD34+ cell dose to undergo this procedure. Here we present the strategy that allows to rescue the outcome of ongoing unsuccessful chemotherapy based mobilizations.

CASE REPORT

All five patients failed to release satisfactory number of CD34+ cells to peripheral blood after chemotherapy plus G-CSF-based mobilization regimen, despite raise in leukocytosis. In this situation, we decided to administer a booster of plerixafor, a specific CXCR4 receptor inhibitor. We observed rapid 2.6 to 16-fold increase of peripheral blood CD34+ cells number that allowed to start aphereses in all cases. Consequently, all five patients who would not otherwise collect required number of CD34+ cells, collected above 2.0×106 CD34+ cells/kg that allowed for hematopoietic stem cell transplantation.

CONCLUSIONS

We would like to suggest that poor mobilizers could be rescued with the timely addition of plerixafor, thus they can avoid another procedure of stem cell mobilization.

Update on the Incidence of Metamizole Sodium-Induced Blood Dyscrasias in Poland

Metamizole sodium (metamizole) is a popular non-opioid analgesic and a common non-prescription product in Poland. Controversy exists regarding the level of risk of agranulocytosis or aplastic anaemia associated with its use. Two previous pharmacovigilance studies conducted in Poland found the risk was low. Twenty-four of the 25 haematology centres that provide specialist care for the 30 million adults in Poland participated in this prospective 12-month study. Twenty-one cases of agranulocytosis, 48 of aplastic anaemia, 15 of neutropenia and 11 of pancytopenia were reported. Of these cases, three (two agranulocytosis; one aplastic anaemia) were judged as being possibly related to metamizole. Crude estimates of the rate of agranulocytosis and aplastic anaemia associated with metamizole were 0.16 and 0.08 cases/million person-days of use, respectively. Ongoing national safety surveillance in Poland shows that, despite the possibility of drug-induced blood dyscrasias with metamizole, the risk is very low.

Indications for allogeneic stem cell transplantation in chronic lymphocytic leukemia: the EBMT transplant consensus

The aim of this project was to identify situations where allogeneic stem cell transplantation (allo-SCT) might be considered as a preferred treatment option for patients with B-cell chronic lymphocytic leukemia (CLL). Based on a MEDLINE search and additional sources, a consented proposal was drafted, refined and approved upon final discussion by an international expert panel. Key elements of the consensus are (1) allo-SCT is a procedure with evidence-based efficacy in poor-risk CLL; (2) although definition of 'poor-risk CLL' requires further investigation, allo-SCT is a reasonable treatment option for younger patients with (i) non-response or early relapse (within 12 months) after purine analogues, (ii) relapse within 24 months after having achieved a response with purine-analogue-based combination therapy or autologous transplantation, and (iii) patients with p53 abnormalities requiring treatment; and (3) optimum transplant strategies may vary according to distinct clinical situations and should be defined in prospective trials. This is the first attempt to define standard indications for allo-SCT in CLL. Nevertheless, whenever possible, allo-SCT should be performed within disease-specific prospective clinical protocols in order to continuously refine transplant indications according to new developments in risk assessment and treatment of CLL.

RNA and protein evidence for haplo-insufficiency in Diamond-Blackfan anaemia patients with RPS19 mutations

The genetic basis of Diamond-Blackfan anaemia (DBA), a congenital erythroid hypoplasia that shows marked clinical heterogeneity, remains obscure. However, the fact that nearly one-quarter of patients harbour a variety of mutations in RPS19, a ribosomal protein gene, provides an opportunity to examine whether haplo-insufficiency of RPS19 protein can be demonstrated in certain cases. To that end, we identified 19 of 81 DBA index cases, both familial and sporadic, with RPS19 mutations. We found 14 distinct insertions, deletions, missense, nonsense and splice site mutations in the 19 probands, and studied mutations in 10 patients at the RNA level and in three patients at the protein level. Characterization of the mutations in 10 probands, including six with novel insertions, nonsense and splice site mutations, showed that the abnormal transcript was detectable in nine cases. The RPS19 mRNA and protein in CD34+ bone marrow cells identified haplo-insufficiency in three cases predicted to have one functional allele. Our data support the notion that, in addition to rare DBA patients with the deletion of one allele, the disease in certain other RPS19 mutant patients is because of RPS19 protein haplo-insufficiency.

Triple transplantation of autologous peripheral blood stem cells each time following conditioning with 100 mg/m2 of melphalan for multiple myeloma patients in poor performance status

Approximately one third of multiple myeloma patients (below 60 years) are diagnosed either in advanced disease or with significant comorbidities. Many other patients referred to transplant centers have already been heavily pretreated with multiple courses of various conventional chemotherapies. These patients are frequently in bad or even grave clinical condition; they are unlikely to survive standard high-dose melphalan (200 mg/m(3)) chemotherapy and autologous hematopoietic stem cell transplantation. Palumbo et al reported a protocol for elderly patients that utilized reduced conditioning (melphalan 100 mg/m(2) three times at 2-month intervals, each time supported by autologous hematopoietic rescue). We have used this protocol as a start to develop a method to induce a remission in the aforementioned subgroup of myeloma patients. Patients with stage III disease and WHO performance status 2 or higher are treated with one or two cycles of cyclophosphamide (2 to 4 g/m(2)) and undergo peripheral blood stem cells collection. Subsequently, they are treated with three to four doses of melphalan (100 mg/m(2)) at 8- to 12-weeks intervals each time supported by infusion of peripheral blood stem cells. To date 13 patients have been entered into the protocol. With one exception of transiently stable disease, the remaining patients obtained at least partial remission and three, complete remission. The compliance was good and better with each subsequent course. For half of the patients the problem was a short duration of response. This method when developed may offer a new treatment alternative for a subgroup of high-risk multiple myeloma patients.

Evaluation of relative anti-myeloma activity of high-dose melphalan followed by the first peripheral blood stem cell transplantation, as compared with the second transplantation, and to VAD chemotherapy

Current treatment in multiple myeloma consists of three courses of chemotherapy in low doses with subsequent hematopoietic stem cell mobilization to the peripheral blood using high-dose cyclophosphamide, collection and conditioning with high-dose chemotherapy (melphalan) followed by retransplantation of autologous peripheral blood stem cells (PBSCT). Only a few studies compare the effects of different phases of therapy on parameters, such as monoclonal immunoglobulin level and the presence of malignant CD38(+) and CD56(+) cells in blood and marrow. The aim of this study was to compare the effects of these two major phases of treatment (conventional and high dose) in the same patients, and furthermore, to compare the effects of the second course of high-dose therapy followed by PBSCT with the effects of the first one. Fifteen patients were included in the study. On average, conventional chemotherapy only slightly reduced the values of all disease markers. In contrast, high-dose therapy resulted in a dramatic effect, rapidly normalizing the values of all parameters. The effects of second PBSCT were only modest compared to the first. These data suggest that high-dose therapy is an efficient method to reduce tumor load in multiple myeloma. Conventional-dose chemotherapy may be simply a waste of time for some patients and may be either omitted or administered after high-dose therapy to consolidate remission.

Reduced number and altered morphology of microglial cells in colony stimulating factor-1-deficient osteopetrotic op/op mice

The numerical density of microglial cells is reduced by 47% in the corpus callosum, by 37% in the parietal cortex and by 34% in the frontal cortex of mice mutant at the op locus which are totally devoid of colony stimulating factor-1 (CSF-1), the major growth factor for macrophages. Moreover, microglia in the frontal cortex of the op/op mice are smaller and have shorter cytoplasmic processes compared to control mice. Study suggests that CSF-1 plays a role in vivo in the formation and maturation of microglia and has little or no effect on perivascular cells.

The effect of chemo- and chemoimmunotherapy on the presence of circulating melanoma cells in peripheral blood. Preliminary results

Reverse transcription and polymerase chain reaction (RT/PCR) with primers specific for tyrosinase allow for a new method of early detection of individual melanoma cells in peripheral blood. Using this test the effect of chemo- and chemoimmunotherapy on the spread of early micrometastatic cancer cells has been evaluated. No significant correlations have been found between RT/PCR results on the one hand and stage of disease, a kind of the therapy protocol used and usage of the therapy as an adjuvant or palliative on the other hand. Thus, although the RT/PCR test for detection of circulating individual melanoma cells might help in identification of minimal residual disease in some patients, it has no application for routine staging of more advanced disease and in monitoring the response to therapy.

The effect of chemo- and chemoimmunotherapy on the presence of circulating melanoma cells in peripheral blood. Preliminary results

Reverse transcription and polymerase chain reaction (RT/PCR) with primers specific for tyrosinase allow for a new method of early detection of individual melanoma cells in peripheral blood. Using this test the effect of chemo- and chemoimmunotherapy on the spread of early micrometastatic cancer cells has been evaluated. No significant correlations have been found between RT/PCR results on the one hand and stage of disease, a kind of the therapy protocol used and usage of the therapy as an adjuvant or palliative on the other hand. Thus, although the RT/PCR test for detection of circulating individual melanoma cells might help in identification of minimal residual disease in some patients, it has no application for routine staging of more advanced disease and in monitoring the response to therapy.

[Subcutaneous immunoglobulin infusion in antibody deficiency substitution of a patient sensitized to intravenous immunoglobulins. Case report]

Patients with severe form of common variable immunodeficiency require chronic immunoglobulin substitution. However, intravenous Ig administration may not be possible in some of them because of serious anaphylactoid reactions. It has been suggested that such patients may tolerate well Ig administration by subcutaneous infusion. A case is described (originally with IgG level of 53 mg/dl) who reacted with anaphylactic shock to intravenous immunoglobulin and now for more than 7 months at 1-2 week intervals receives immunoglobulin by subcutaneous infusion without any adverse reactions and maintaining IgG level above 400 mg/dl. In contrast to the period proceeding immunoglobulin substitution, the patient remains free of bacterial infection during last 7 months.

The use of bone-marrow-derived fibroblastoid cells and fresh bone marrow in the treatment of bone defects: an experimental study

Bone-marrow aspirate (containing bone progenitor cells), in vitro expanded autologous bone-marrow-derived stromal fibroblastoid cells, and a combination thereof were tested for the potential to fill bone defects. They were compared to grafts of fresh autologous bone or allogeneic devitalized bone. Mandibular defects in rabbits were chosen for this study. The best results were obtained with a combination of in vitro expanded bone-marrow-derived stromal fibroblastoid cells and fresh autologous bone marrow or fresh autologous marrow alone. The effects of these two grafts were similar to grafts of fresh autologous bone and significantly superior to grafts of devitalized allogeneic bone providing only a bone matrix. The in vitro expanded marrow stromal cells induced very significant bone ingrowth, and their effects were only slightly inferior to fresh autologous bone but were superior to devitalized allogeneic bone. These studies suggest that bone marrow is a good source of osteogenic cells both for immediate transplantation and for in vitro expansion and subsequent transplantation.

Cytokine regulation of the macrophage (M phi) system studied using the colony stimulating factor-1-deficient op/op mouse

The macrophage (M phi) lineage is more complex than other myeloid lineages of hematopoietic cells and includes strikingly different end cells such as Kupffer cells, alveolar M phi, histiocytes, serosal M phi, synovial type A cells, microglia, osteoclasts, and possibly dendritic cells. These cells are formed under the influence of primary M phi growth factors such as colony stimulating factor (CSF)-1, granulocyte-M phi (GM)-CSF, and interleukin-3. The dissection of the system has been greatly facilitated by discovery of the osteopetrotic op/op mouse, which has a spontaneous knockout of the gene for CSF-1 and possesses generalized but differential deficiency of various local subpopulations of M phi. Studies using this model indicate that the M phi lineage is split into CSF-1-dependent and CSF-1-independent cells that are largely independently regulated. These contribute variably to different local populations and have largely, but not totally, overlapping functions. Both CSF-1 and GM-CSF are responsible for transition of cells of the M phi lineage from bone marrow to blood, and from blood to tissues, and have a critical extramedullary role. Regulation of the M phi system by CSF-1 is complex, with some local populations dependent on circulating CSF-1 and some supported exclusively by locally produced CSF-1. Colony stimulating factor-1-dependent M phi are not required for the generation of a specific immune response. Instead, most likely they play a regulatory role in various tissue reactions including responses to bacterial infection, neoplasia, and atherosclerosis. A hypothetical major role of CSF-1-independent M phi is to collaborate with lymphocytes in mounting an immune response. These issues need further exploration using animals with knockouts of genes for other M phi growth and activation factors and their receptors.

Colony-stimulating factor 1-dependent resident macrophages play a regulatory role in fighting Escherichia coli fecal peritonitis

Osteopetrotic op/op mice have less than 5% of the normal number of macrophages in the peritoneal cavity (W. Wiktor-Jedrzejczak, A. Ahmed, C. Szczylik, and R.R. Skelly, J. Exp. Med. 156:1516-1527, 1982). Fecal peritonitis was induced by intraperitoneal injection of 0.5 ml of 5% autoclaved feces in saline along with Escherichia coli grown from feces of mice of the same colony and added in doses ranging between 10 and 10(6) CFU. Such infection led to a septic shock and either was lethal within 24 h or became cured without additional treatment of the mice. The op/op mice survived administration of 30-times-smaller doses of bacteria compared with their normal littermates. Analysis of the kinetics of cellular changes in the peritoneal cavity associated with such infection revealed that this increased susceptibility of macrophage-deficient mice cannot be explained by a direct role of macrophages in combating the infection. Instead, it appeared that the increased susceptibility to fatal fecal peritonitis was most likely due to delayed and impaired recruitment of neutrophils to the site of infection in mutant mice. The increased susceptibility of the op/op mice to E. coli fecal peritonitis was not due to their possible increased sensitivity to endotoxin, since the mutant mice tolerated lipopolysaccharide doses more than twice those tolerated by control littermates. On the other hand, their susceptibility to exogenous tumor necrosis factor alpha and interleukin-1 alpha was increased. Both mutant op/op and control mice were able to survive secondary challenge with 10(6) E. coli (administered along with feces) lethal for both types of mice on primary challenge. These data suggest that colony-stimulating factor 1-dependent resident peritoneal macrophages play a role in controlling primary infection by recruiting neutrophils and are not required for efficient response to secondary infection.

Impaired tumor growth in colony-stimulating factor 1 (CSF-1)-deficient, macrophage-deficient op/op mouse: evidence for a role of CSF-1-dependent macrophages in formation of tumor stroma

Macrophages have been suggested to play a major role in the immune response to cancer. They have also been suggested to stimulate the formation of tumor stroma and to promote tumor vascularization. The availability of the op/op mouse, which has no endogenous colony-stimulating factor 1 (CSF-1) and which possesses a profound macrophage deficiency, provides a new model to verify these notions. Subcutaneous growth of transplantable Lewis lung cancer (LLC) is markedly impaired in the op/op mice compared with normal littermates. Treatment of tumor-bearing op/op mice with human recombinant CSF-1 corrects this impairment. Histological analysis of tumors grown in op/op and normal mice revealed marked differences. Tumors grown in op/op mice display a decreased mitotic index and pronounced necrosis, particularly hemorrhagic. Moreover, particularly in the op/op tumors, peculiar sinusoid-like abortive vessels (not filled with blood) have been observed. These tumors, in contrast to tumors grown in normal mice, are almost deprived of regular arteries and veins. In contrast to tumors grown in normal mice, they exhibit almost no Sirius red-stained collagenous fibers and Gomori silver-stained reticular fibers. Our data suggest that the CSF-1-dependent macrophage subpopulation missing in op/op mice plays a primary role in supporting tumor stroma formation and tumor vascularization in murine LLC tumors.

Potentiation of antitumor effects of tumor necrosis factor alpha and interferon gamma by macrophage-colony-stimulating factor in a MmB16 melanoma model in mice

The efficacy of systemic infusion of recombinant human macrophage-colony-stimulating factor (M-CSF) in combination with local treatment with human recombinant tumor necrosis factor (TNF) alpha and mouse recombinant interferon (IFN) gamma was studied in vivo on a subclone of B16 melanoma (MmB16) in mice. Short-term intravenous administration of M-CSF at a dose of 10(6) units daily had no antitumor effect in vivo. Similarly, local treatment of tumor with TNF alpha (5 micrograms daily) did not produce any therapeutic effect. However, simultaneous administration of the same dose of TNF alpha with IFN gamma (1000 units daily) resulted in a synergistic effects manifested by the retardation of tumor growth. Addition of systemic infusion of M-CSF to the local therapy with TNF alpha and IFN gamma induced further augmentation of antitumor efficacy and delayed progression of MmB16 melanoma. The strengthened antitumor effect of combination therapy including M-CSF, TNF alpha and IFN gamma was most probably due to the increased release of monocytes from the bone marrow, their recruitment into the site of tumor growth and subsequent local stimulation of their antitumor activity.

Granulocyte-macrophage colony-stimulating factor corrects macrophage deficiencies, but not osteopetrosis, in the colony-stimulating factor-1-deficient op/op mouse

The op mutation in the mouse is in the coding region of the colony-stimulating factor-1 (CSF-1) gene, prevents formation of biologically active factor, and, thus, results in generalized macrophage deficiency and, in osteopetrosis, secondary to deficiency of osteoclasts. Although a few macrophages and osteoclasts are present in these mutants, it was not clear whether the inability of endogenous granulocyte-macrophage CSF (GM-CSF) to compensate for the absence of CSF-1 was due to the limitations of biological activity of this molecule or to its inability to reach respective target populations. In this study, we examined whether sc GM-CSF in large doses (20-40 micrograms/mouse.day) for 3 weeks would correct some or all of the deficiencies observed in mutant mice. All organ macrophage populations tested (liver, spleen, thymus, marrow, pleural, and peritoneal cavity) were significantly increased, reaching levels exceeding those observed in normal mice. Restoration of peritoneal and pleural macrophage populations by sc GM-CSF is of particular interest, because it was not previously observed in op/op mice treated with sc CSF-1. In contrast, there was no indication of increased bone resorption, no appearance of osteoclasts, and no tooth eruption in response to GM-CSF treatment. These data suggest that GM-CSF is able to compensate for the absence of CSF-1 during macrophage formation, but is unable to play a similar role in osteoclast differentiation.