Pharmacoeconomic impact of up-front use of plerixafor for autologous stem cell mobilization in patients with multiple myeloma

Background aimsStem cell collection can be a major component of overall cost of autologous stem cell transplantation (ASCT). Plerixafor is an effective agent for mobilization; however, it is often reserved for salvage therapy because of its high cost. We present data on the pharmacoeconomic impact of the use of plerixafor as an up-front mobilization in patients with multiple myeloma (MM).MethodsPatients with MM who underwent ASCT between January 2008 and April 2011 at the Mount Sinai Medical Center were reviewed retrospectively. In April 2010, practice changes were instituted for patients with MM to delay initiation of granulocyte-colony-stimulating factor (G-CSF) support from day 0 to day +5 and to add plerixafor to G-CSF as an up-front autologous mobilization. Targets of collection were 5–10 × 10⁶ CD34⁺ cells/kg.ResultsOf 50 adults with MM who underwent ASCT, 25 received plerixafor/filgrastim and 25 received G-CSF alone as an up-front mobilization. Compared with the control, plerixafor mobilization yielded higher CD34⁺ cell content (16.1 versus 8.4 × 10⁶ CD34⁺ cells/kg; P = 0.0007) and required fewer sessions of apheresis (1.9 versus 3.1; P = 0.0001). In the plerixafor group, the mean number of plerixafor doses required per patient was 1.8. Although the overall cost of medications was higher in the plerixafor group, the cost for blood products and overall cost of hospitalization were similar between the two groups.ConclusionsUp-front use of plerixafor is an effective mobilization strategy in patients with MM and does not have a substantial pharmacoeconomic impact in overall cost of hospitalization combined with the apheresis procedure.     

Decrease of CD4+ T-lymphocytes in children exposed to environmental lead

The effects of environmental lead on the immune system of young children were assessed by determining the peripheral blood lymphocytes CD3⁺, CD4⁺, CD8⁺, B(CD19⁺) counts, and natural killer (CD16⁺ CD56⁺) cells in 35 preschool children whose mean blood lead level was 140.6 μg/L. The results were compared to an age- and sex-matched control group with a mean blood lead level of 64.3 μg/L. Compared to the controls, a significant reduction in the percentage of CD4⁺ cells and a significant increase of CD8⁺ cells were seen in the high-lead group. The negative correlation between the percentage of CD4⁺ cells and blood lead levels was found to be significant (p<0.01). These results suggest that exposure to environmental lead might result in alterations in the immune function of young children.     

The effect of recombinant human granulocyte/macrophage-colony-stimulating factor (rHu GM-CSF) and rHu G-CSF administration on neutrophil chemiluminescence assay in patients following cyclic chemotherapy

Secondary infections related to neutropenia and functional defects of phagocytes are common consequences in patients treated for cancer. The hematopoietic colony-stimulating factors (CSF) have been introduced into clinical practice as additional supportive measures that can reduce the incidence of infectious complications in patients with cancer and neutropenia. The aim of this study was to determine the role of␣granuolcyte/macrophage(GM)-CSF and granulocyte(G)-CSF in enhancing in vivo human neutrophil function. A luminol-dependent chemiluminescence assay was developed to evaluate whether the repair in neutropenia accompanies the ability of neutrophils to function. A dose of 5 μg G-CSF kg⁻¹ day⁻¹ [recombinant human (rHu) G-CSF; filgrastim] or 250 μg GM-CSF m⁻² day⁻¹ (rHu GM-CSF; molgramostim) was administered subcutaneously once daily to 12 metastatic cancer patients being treated with different cytotoxic regimens. All injections of CSF were given after the initiation of neutropenia and continued until the occurrence of an absolute neutrophil recovery. rHu GM-CSF and rHu G-CSF, administered once daily at the 250 μg m⁻² day⁻¹ and 5 μg kg⁻¹ day⁻¹ level, were effective in increasing the absolute neutrophil count and neutrophil function, as measured by an automated chemiluminescence system. Received: 26 February 1998 / Accepted: 21 May 1998     

Consistent bone marrow-derived cell mobilization following repeated short courses of granulocyte–colony-stimulating factor in patients with amyotrophic lateral sclerosis: results from a multicenter prospective trial

Background and aimsThe aim of this study was to evaluate and characterize the feasibility and safety of bone marrow-derived cell (BMC) mobilization following repeated courses of granulocyte–colony stimulating factor (G-CSF) in patients with amyotrophic lateral sclerosis (ALS).MethodsBetween January 2006 and March 2007, 26 ALS patients entered a multicenter trial that included four courses of BMC mobilization at 3-month intervals. In each course, G-CSF (5 μg/kg b.i.d.) was administered for four consecutive days; 18% mannitol was also given. Mobilization was monitored by flow cytometry analysis of circulating CD34⁺ cells and by in vitro colony assay for clonogenic progenitors. Co-expression by CD34⁺ cells of CD133, CD90, CD184, CD117 and CD31 was also assessed.ResultsTwenty patients completed the four-course schedule. One patient died and one refused to continue the program before starting the mobilization courses; four discontinued the study protocol because of disease progression. Overall, 89 G-CSF courses were delivered. There were two severe adverse events: one prolactinoma and one deep vein thrombosis. There were no discontinuations as a result of toxic complications. Circulating CD34⁺ cells were monitored during 85 G-CSF courses and were always markedly increased; the range of median peak values was 41–57/μL, with no significant differences among the four G-CSF courses. Circulating clonogenic progenitor levels paralleled CD34⁺ cell levels. Most mobilized CD34⁺ cells co-expressed stem cell markers, with a significant increase in CD133 co-expression.ConclusionsIt is feasible to deliver repeated courses of G-CSF to mobilize a substantial number of CD34⁺ cells in patients with ALS; mobilized BMC include immature cells with potential clinical usefulness.     

Defining “poor mobilizer” in pediatric patients who need an autologous peripheral blood progenitor cell transplantation

The definition of poor mobilizers is not clear in pediatric patients undergoing autologous peripheral blood hematopoietic progenitor cell (HPC) mobilization. Most studies conducted in children define those variables related to the collection of HPC after leukapheresis, but the information regarding exclusively the mobilization process is scarce. In our experience, most children (92.2%) reach the target CD34⁺ cell dose for autologous peripheral blood progenitor cell transplantation if CD34⁺ cell count was higher than 10/μL. No differences were observed between those with >20 CD34⁺ cells/μL and 11–20 CD34⁺ cells/μL. In this study, we analyzed the variables that influence CD34⁺ cell count; we found that prior use of radiotherapy was the main variable related to poor mobilization. Patients diagnosed with Ewing sarcoma, treated with radiotherapy and mobilized with standard doses of granulocyte colony-stimulating factor (G-CSF) were also at a high risk of mobilization failure. In these patients, we should consider mobilization with high dose G-CSF and be prepared with new mobilization agents to avoid delay on their course of chemotherapy.     

Expansion and characteristics of human T regulatory type 1 cells in co-cultures simulating tumor microenvironment

Objective Chronic inflammation and cancer development are associated with dysregulated immune responses and the presence of regulatory T cells (T_reg). To study the role of T_reg in tumor cell escape from immune surveillance, an in vitro model simulating the tumor microenvironment and promoting the induction and expansion of IL-10⁺ T_reg type 1 (Tr1) was established. Methods An in vitro co-culture system (IVA) included an irradiated head and neck squamous cell carcinoma cell line, immature dendritic cells (iDC), CD4⁺CD25⁻ T cells and cytokines, IL-2 (10 IU/ml), IL-10 (20 IU/ml), IL-15 (20 IU/ml) ± 1 nM rapamycin. Autologous iDC and CD4⁺CD25⁻ T cells were obtained from the peripheral blood of 15 normal donors. Co-cultures were expanded for 10 days. Proliferating lymphocytes were phenotyped by multi-color flow cytometry. Their suppressor function was measured in CFSE inhibition assays ± neutralizing anti-IL-10 mAb and using transwell cultures. Culture supernatants were tested for IL-4, IL-10, TGF-β and IFN-γ in ELISA. Results In the IVA, low doses of IL-2, IL-10 and IL-15 promoted induction and expansion of CD3⁺CD4⁺CD25⁻IL2Rβ⁺IL2Rγ⁺FoxP3⁺CTLA-4⁺IL-10⁺ cells with suppressor activity (mean suppression ± SD = 58 ± 12%). These suppressor cells produced IL-10 (mean ± SD = 535 ± 12 pg/ml) and TGF-β (mean ± SD = 512 ± 38 pg/ml), but no IL-4 or IFN-γ. Suppressor function of co-cultures correlated with the percent of expanding IL-10⁺ Tr1 cells (r ² = 0.9; P < 0.001). The addition of rapamycin enriched Tr1 cells in all co-cultures. Neutralizing anti-IL-10 mAb abolished suppressive activity. Suppression was cell-contact independent. Conclusion The tumor microenvironment promotes generation of Tr1 cells which have the phenotype distinct from that of CD4⁺CD25^highFoxP3⁺ nTreg and mediate IL-10 dependent immune suppression in a cell-contact independent manner. Tr1 cells may play a critical role in cancer progression.     

Mobilization of CD34~+CD38~- hematopoietic stem cells after priming in acute myeloid leukemia

AIM: To evaluate quantitatively and qualitatively the different CD34+cell subsets after priming by chemotherapy granulocyte colony-stimulating factor(± G-CSF)in patients with acute myeloid leukemia.METHODS: Peripheral blood and bone marrow sampleswere harvested in 8 acute myeloid leukemia patients during and after induction chemotherapy. The CD34/CD38 cell profile was analyzed by multi-parameter flow cytometry. Adhesion profile was made using CXC chemokine receptor 4(CXCR4)(CD184), VLA-4(CD49d/CD29) and CD47.RESULTS: Chemotherapy ± G-CSF mobilized immature cells(CD34+CD38 population), while the more mature cells(CD34+CD38lowand CD34+CD38+populations) decreased progressively after treatment. Circulating CD34+cells tended to be more sensitive to chemotherapy after priming with G-CSF. CD34+cell mobilization was correlated with a gradual increase in CXCR4 and CD47expression, suggesting a role in cell protection and the capacity of homing back to the marrow.CONCLUSION: Chemotherapy ± G-CSF mobilizes into the circulation CD34+bone marrow cells, of which, the immature CD34+CD38-cell population. Further manipulations of these interactions may be a means with which to control the trafficking of leukemia stem cells to improve patients’ outcomes.     

In vitro percutaneous absorption of boron as boric acid, borax, and disodium octaborate tetrahydrate in human skin: a summary

Literature from the first half of this century reports concern for toxicity from topical use of boric acid, but assessment of percutaneous absorption has been impaired by lack of analytical sensitivity. Analytical methods in this study included inductively coupled plasmamass spectrometry which now allows quantitation of percutaneous absorption of¹⁰B in¹⁰B-enriched boric acid, borax and disodium octaborate tetrahydrate (DOT) in biological matrices. In vitro human skin percent doses of boric acid absorbed were 1.2 for a 0.05% solution, 0.28 for a 0.5% solution, and 0.70 for a 5.0% solution. These absorption amounts translated into flux values of, respectively, 0.25, 0.58, and 14.58 μg/cm²/h, and permeability constants (K _p ) of 5.0 x 10^-4, 1.2 x 10^-4, and 2.9 x 10^-4 cm/h for the 0.05%, 0.5%, and 5.0% solutions. The above in vitro doses were at infinite, 1000 μL/cm² volume. At 2 μL/cm² (the in vivo dosing volume), flux decreased some 200-fold to 0.07 μg/cm²/h andK _p of 1.4 x 10^-6 cm/h, while percent dose absorbed was 1.75%. Borax dosed at 5.0%/1000 μL/cm² had 0.41 percent dose absorbed, flux at 8.5 μg/cm²/h, andK _p was 1.7 x 10^-4 cm/h. Disodium octaborate tetrahydrate (DOT) dosed at 10%/1000 μL/cm² was 0.19 percent dose absorbed, flux at 7.9 μg/cm²/h, andK _p was 0.8 x ICH cm/h. These in vitro results from infinite doses (1000 μL/cm²) were a 1000-fold greater than those obtained in the companion in vivo study. The results from the finite (2 μL/cm²) dosing were closer (10-fold difference) to the in vivo results. General application of infinite dose percutaneous absorption values for risk assessment is questioned by these results.     

Stem cell transplantation for metastatic breast cancer: analysis of tumor contamination

The purpose of this study was to determine the efficacy, engraftment kinetics, effect of bone marrow tumor contamination, and safety of high-dose therapy and granulocyte-colony stimulating factor (G-CSF) mobilized peripheral blood progenitor cell (PBPC) support for patients with responding metastatic breast cancer. Forty two patients underwent G-CSF (10 μg/kg) stimulated PBPC harvest. PBPC and bone marrow aspirates were analyzed by histologic and immunocytochemical methods for tumor contamination. Thirty-seven patients received high-dose therapy consisting of cyclophosphamide 6 g/m², thiotepa 500 mg/m², and carboplatin 800 mg/m² (CTCb) given as an infusion over 4 d followed by PBPC reinfusion and G-CSF (5 μg/kg) support. No transplant related deaths or grade 4 toxicity was recorded. CD34+ cells/kg infused was predictive of neutrophil and platelet recovery. With a median follow-up of 38 months, three year survival was 44% with relapse-free survival of 19%. Histological bone marrow involvement, found in 10 patients, was a negative prognostic factor and was associated with a median relapse-free survival of 3.5 months. Tumor contamination of PBPC by immunohistochemical staining was present in 22.5% of patients and found not to be correlated with decreased survival. G-CSF stimulated PBPC collection followed by a single course of high dose chemotherapy and stem cell infusion with G-CSF stimulated marrow recovery leads to rapid, reliable engraftment with low toxicity and promising outcome in women with responding metastatic breast cancer.     

Functional characterisation of LKT1, a K+ uptake channel from tomato root hairs, and comparison with the closely related potato inwardly rectifying K+ channel SKT1 after expression in Xenopus oocytes

A cDNA encoding a novel inwardly rectifying potassium (K⁺ _in) channel, LKT1, was cloned from a root-hair-specific cDNA library of tomato (Lycopersicon esculentum Mill.). The LKT1 mRNA was shown to be most strongly expressed in root hairs by Northern blot analysis. The LKT1 channel is a member of the AKT family of K⁺ _in channels previously identified in Arabidopsis thaliana (L.) Heynh. and potato (Solanum tuberosum L.). Moreover, LKT1 is closely related (97% identical amino acids) to potato SKT1. An electrophysiological comparison of the two channels should therefore assist the identification of possible molecular bases for functional differences. For this comparison, both channels were functionally expressed and electrophysiologically characterised within the same expression system, i.e. Xenopus laevis oocytes. Voltage-clamp measurements identified LKT1 as a K⁺-selective inward rectifier which activates with slow kinetics upon hyperpolarising voltage pulses to potentials more negative than −50 mV. The activation potential of LKT1 is shifted towards positive potentials with respect to SKT1 which might be due to single amino acid exchanges in the rim of the channel's pore region or in the S4 domain. Like SKT1, LKT1 reversibly activated upon shifting the external pH from 6.6 to 5.5, which indicates a physiological role for pH-dependent regulation of AKT-type K⁺ _in channels. The pharmacological inhibitor Cs⁺, applied externally, inhibited K⁺ _in currents mediated by LKT1 and SKT1 half-maximally with a concentration (IC₅₀) of 21 μM and 17 μM, respectively. In conclusion, LKT1 may serve as a low-affinity influx pathway for K⁺ into root hair cells. Comparison of homologous K⁺ _in rectifiers from different plant species expressed in the same heterologous system allows conclusions to be drawn in respect to structure-function relationships. Received: 3 August 1999 / Accepted: 2 November 1999