scholarly journals PERIPHERAL BLOOD LYMPHOCYTE PHENOTYPE OF ZAP-70+ AND ZAP-70− PATIENTS WITH B-CELL CHRONIC LYMPHOCYTIC LEUKAEMIA

2015 ◽  
Vol 37 (1) ◽  
pp. 73-76 ◽  
Author(s):  
A Rivkina ◽  
I Holodnuka Kholodnyuk ◽  
M Murovska ◽  
M Soloveichika ◽  
S Lejniece

Background: Up to now, the immune status of chronic lymphocytic leukemia (CLL) patients in association with the expression of zeta-chain-associated protein kinase 70 (ZAP-70) in leukemic cells has not been evaluated. Aim: The aim of this work was the study of the peripheral blood (PB) T-lymphocyte phenotypes in ZAP-70-positive (ZAP-70+) and ZAP-70-negative (ZAP-70−) untreated patients with CLL. Materials and Methods: ZAP-70-, CD25-, CD3-, CD4-, and CD8-positive lymphocytes were enumerated by flow cytometry in PB of 120 untreated CLL patients. CD8+, CD3+CD4+ and CD3+CD25+ cells were counted for the non-leukemic lymphocytes. Results: The patients were distributed into two groups: the ZAP-70+ group of high CLL progression (n = 61), and the ZAP-70− group of low CLL progression (n = 59). In the ZAP-70+ group, the ratio CD4/CD8 (0.33 ± 0.62; p = 0.001) and the numbers of the CD3+ (34.8 ± 8.1%; p = 0.01), CD3+CD4+ (24.4% ± 4.8; p = 0.001), and CD3+CD25+ (6.2 ± 0.91%; p = 0.001) lymphocytes were reduced and the percentage of the CD8+ cells (73.1 ± 4.6%; p = 0.0001) was above the norm. In the ZAP-70− group, the number of the CD3+CD4+ cells (36.9 ± 6.1%; p = 0.001) was within the norm, but the numbers of the CD8+ (11.3 ± 1.1%; p = 0.0001) and CD3+ (41.2 ± 5.3%; p = 0.05) lymphocytes were reduced; the ratio CD4/ CD8 (3.26 ± 0.88; p = 0.001) and the percentage of the CD3+CD25+ cells (27.1 ± 3.4%; p = 0.0001) were above the norm. Conclusions: Our data show that the increased CD4/CD8 ratio, caused by the reduced number of the CD8+ lymphocytes, and the increased number of CD3+CD25+ cells are characteristic for the ZAP-70− group (slow progressing) of untreated CLL patients. In ZAP-70+ patients, the CD4/CD8 ratio was significantly below the norm indicating an active disease process. Results of our study contribute to identification of CLL patients with different prognosis in routine diagnostic/prognostic procedures.

Blood ◽  
1980 ◽  
Vol 55 (4) ◽  
pp. 702-705
Author(s):  
ER Richie ◽  
MP Sullivan ◽  
J van Eys

A 5-yr-old girl with acute lymphocytic leukemia presented with moderate hepatomegaly, marked splenomegaly, but no evidence of a mediastinal mass. The peripheral blood white count was 270 x 10(9)/liter with 99% leukemic cells. Surface marker analysis showed the lymphoblasts to be E- rosette negative and complement receptor positive. The patient's leukemic cells were unreactive with anti-p23,30, which detects Ia-like antigens, and strongly reactive with A99 anti-T-cell serum, which reacts with normal human thymocytes and peripheral blood T cells. The percentage of leukemic cells bearing complement receptors diminished during relapse. The leukemic cells obtained at diagnosis and during relapse were nonreactive to mitogens and alloantigens and failed to stimulate proliferation of normal lymphocytes in mixed lymphocyte culture. There was no evidence for active suppression of normal lymphocyte reactivity mediated by the leukemic cells. The surface marker and functional profile of these leukemic cells is consistent with that of an early stage in T-cell maturation.


Blood ◽  
2003 ◽  
Vol 101 (1) ◽  
pp. 292-294 ◽  
Author(s):  
Fabianne Philippoussis ◽  
Chantal Arguin ◽  
Véronique Mateo ◽  
Ann-Muriel Steff ◽  
Patrice Hugo

Abstract A major drawback of the current antineoplastic treatments is their lack of specificity toward cancer cells, because they are most often cytotoxic to normal cells, thus creating related side effects. Hence, the identification of new apoptosis-inducing agents, specifically targeting malignant cells while sparing their normal counterparts, is of crucial interest. We show here that monoglycerides, a family of lipids consisting of a single fatty acid attached to a glycerol backbone, induce cell death in several human leukemic cell lines. Importantly, treatment of primary leukemic cells, obtained from B-cell chronic lymphocytic leukemia patients, resulted in rapid apoptosis. In striking contrast, resting or activated human peripheral blood mononuclear cells from healthy individuals were resistant to the same treatment. Therefore, these compounds could represent potential antileukemic drugs or could allow for the design of novel therapeutic agents applied to leukemia.


2019 ◽  
Vol 5 (10) ◽  
pp. FSO425
Author(s):  
Ricardo García-Muñoz ◽  
María-Josefa Nájera ◽  
Jesús Feliu ◽  
Judith Antón-Remírez ◽  
Enrique Ramalle-Gómara ◽  
...  

Aim: To analyze the effects of subcutaneous or intravenous rituximab + lymphokine-activated killer cells, obinutuzumab or ibrutinib on natural killer (NK) cell levels in chronic lymphocytic leukemia and follicular lymphoma patients. Patients & methods: The distribution of peripheral blood NK cells of 31 patients was analyzed by flow cytometry. Results: We detected a decrease of NK cells in peripheral blood below normal range after obinutuzumab treatment. During maintenance treatment with subcutaneous rituximab, an NK cell reduction was less pronounced than after intravenous rituximab treatment, despite lymphokine-activated killer cell infusions. Conclusion: After one dose of obinutuzumab, each NK cell in peripheral blood destroys 25 leukemic cells.


Blood ◽  
1981 ◽  
Vol 57 (5) ◽  
pp. 879-882 ◽  
Author(s):  
E Morgan ◽  
CC Hsu

Abstract Peripheral blood samples from 57 children with newly diagnosed E- rosette-negative, surface-immunoglobulin negative acute lymphocytic leukemia (ALL) were studied for the presence of a leukemia-associated antigen (ALLA). Ficoll-Hypaque separated cells were tested using a rabbit antiserum to human null lymphoblasts and an indirect immunofluorescent assay. The percentage of ALLA-positive cells were compared to the percentage of lymphoblasts determined by differential counts of a Wright-Giemsa-stained smear of a concurrently obtained peripheral blood sample. The mean ratio of percentage of lymphoblasts to percentage of ALLA-positive cells was 0.90. However, in 13 patients, the ratio of percent of ALLA-positive cells to percent of lymphoblasts was equal to or greater than 2:1. In the blood of 6 additional children (5 newly diagnosed, 1 relapsed patient) in whom no morphologically identifiable lymphoblasts were detected. ALLA-positive cells were present (7%-49%). These results indicate that testing for ALLA-positive cells in a sensitive technique for detection of leukemic cells in children with ALLA-positive ALL.


2020 ◽  
Vol 4 (5) ◽  
pp. 893-905
Author(s):  
Boris A. Bartholdy ◽  
Xiahoua Wang ◽  
Xiao-Jie Yan ◽  
Marién Pascual ◽  
Manxia Fan ◽  
...  

Abstract Intraclonal subpopulations of circulating chronic lymphocytic leukemia (CLL) cells with different proliferative histories and reciprocal surface expression of CXCR4 and CD5 have been observed in the peripheral blood of CLL patients and named proliferative (PF), intermediate (IF), and resting (RF) cellular fractions. Here, we found that these intraclonal circulating fractions share persistent DNA methylation signatures largely associated with the mutation status of the immunoglobulin heavy chain locus (IGHV) and their origins from distinct stages of differentiation of antigen-experienced B cells. Increased leukemic birth rate, however, showed a very limited impact on DNA methylation of circulating CLL fractions independent of IGHV mutation status. Additionally, DNA methylation heterogeneity increased as leukemic cells advanced from PF to RF in the peripheral blood. This frequently co-occurred with heterochromatin hypomethylation and hypermethylation of Polycomb-repressed regions in the PF, suggesting accumulation of longevity-associated epigenetic features in recently born cells. On the other hand, transcriptional differences between paired intraclonal fractions confirmed their proliferative experience and further supported a linear advancement from PF to RF in the peripheral blood. Several of these differentially expressed genes showed unique associations with clinical outcome not evident in the bulk clone, supporting the pathological and therapeutic relevance of studying intraclonal CLL fractions. We conclude that independent methylation and transcriptional landscapes reflect both preexisting cell-of-origin fingerprints and more recently acquired hallmarks associated with the life cycle of circulating CLL cells.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2431-2431
Author(s):  
Marta Coscia ◽  
Francesca Pantaleoni ◽  
Chiara Riganti ◽  
Candida Vitale ◽  
Micol Rigoni ◽  
...  

Abstract Abstract 2431 Chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease. A very reliable prognosticator is the mutational status of the tumor immunoglobulin heavy chain variable region (IGHV): patients with unmutated (UM) IGHV have a worse prognosis than patients with mutated (M) IGHV. Soluble factors (i.e. IL-4 and CD40L) and cellular components of the local microenvironment [i.e. bone marrow stromal cells (BMSC) and nurse-like cells (NLCs)] are important survival factors for CLL B cells. It is currently unknown to what extent UM and M CLL cells depend on the local microenvironment for their survival. We have evaluated the spontaneous apoptotic rate of tumor cells isolated by immunomagnetic selection from the peripheral blood (PB) of M and UM CLL patients. Both M and UM CLL B cells underwent spontaneous apoptosis throughout the culture period. However, the UM CLL B cells showed a significantly higher degree of apoptosis in 7-day cultures as compared to M CLL B cells. In both M and UM CLL B cells, high basal levels of Bcl-2 expression and NF-kB activity were detected. On day 7, the percentage of Bcl-2+ leukemic cells was significantly lower in UM than in M CLL B cells. EMSA test showed that NF-kB was totally inactivated in UM CLL B cells and only partially reduced in M CLL B cells. Quantitative analysis of RelA and RelB subunits showed that NF-kB inactivation in UM CLL B cells consisted in a strong reduction of both RelA and RelB nuclear expression. CD40L, IL-4 and stromal cells significantly improved UM CLL B cells viability and significantly recovered Bcl-2 expression. The protective effect exerted by these stimuli was totally independent from the recovery of NF-kB expression. Indeed, after 7 days of culture, the UM CLL B cells had completely lost the nuclear form of NF-kB, and none of the stimuli was capable of restoring it. We observed that UM CLL cells were less susceptible to spontaneous apoptosis when cultured as unfractionated peripheral blood mononuclear cells (M or UM PBMC) as compared to purified leukemic cells (M and UM CLL B cells). The reduced apoptosis detected in UM PBMC was accompanied by a retained expression of Bcl-2 and by a restored activity of NF-kB and suggested the presence of a pro-survival element in the peripheral blood of these patients. To investigate the role of NLC in rescuing UM CLL B cells from apoptosis we first evaluated whether M and UM PBMC generated NLC with the same efficiency. Unexpectedly, the former generated significantly higher numbers of NLC than UM PBMC. Despite the lack of generation of NLC, CLL B cells viability was very similar in the non-adherent fraction of M and UM PBMC on day 7 and 14 of culture. This observation ruled out a role for NLC in supporting UM CLL B cells survival. Conversely, a pro-survival effect on UM CLL B cells was exerted by autologous T cells. Indeed, a significant reduction in the apoptotic rate of leukemic cells was observed when purified UM CLL B cells were cultured in the presence of autologous peripheral blood T cells (UM CLL B cell/T cell co-cultures). NF-kB activity was completely lost in UM CLL B cells cultured for 7 days in medium alone whereas it was restored in UM CLL B cells / T cells co-cultures. The prosurvival effect of circulating T cells was exerted both in cell-to-cell contact and in trans-well condition and was associated to increased secretions of tumor necrosis factor-alpha (TNF-α), platelet-derived growth factor (PDGF)-BB and interleukin-8 (IL-8) as detected by analyses of supernatants through a Multiplex system. These data indicate that despite their more aggressive features, UM CLL B cells are more susceptible to spontaneous apoptosis and depend from environmental prosurvival signals. This vulnerability of UM CLL B cells can be exploited as a selective target of therapeutic interventions. Disclosures: Boccadoro: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Massaia: Novartis: Honoraria, Research Funding.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3895-3895
Author(s):  
Yair Herishanu ◽  
Inbal Hazan-Hallevi ◽  
Sigi Kay ◽  
Varda Deutsch ◽  
Aaron Polliack ◽  
...  

Abstract Abstract 3895 Chronic lymphocytic leukemia (CLL) cells depend on their microenvironment for proliferation and survival. Ectonucleotidase CD39 has anti-inflammatory properties as it hydrolyzes pro-inflammatory extra-cellular ATP, generates anti-inflammatory adenosine and also protects regulatory T cells from ATP-induced cell death. In this study we investigated the clinical significance of CD39 expression on CD4+T-cells in 45 patients with CLL as well as its compartmental regulation and explored the possible mechanisms for its induction. Compared to healthy individuals, CD4+CD39+ lymphocytes were increased in the peripheral blood of patients with CLL (4.6%±2.28 vs. 17.3%±12.49, respectively, p=0.004), and correlated with advanced stage of disease (9.72%±5.76, 18.15%±12.03 and 25.90%±16.34, of CD4+ lymphocytes, in patients with Rai stages 0, 1+2 and 3+4, respectively, p=0.019). CD4+CD39+ cells were also higher in patients with CLL who needed therapeutic intervention (untreated; 12.99%±10.63 vs treated; 22.21%±12.88, p=0.01) and in those who were ZAP70+ or had b2-microglobulin levels>3g/L. There were more CD4+CD39+ lymphocytes in the bone marrow compartment (22.25%±16.16) than in the peripheral blood (16.60%±15.84, p=0.009). In-vitro studies showed that CD39 can be induced on CD4+cells by exposure to ATP or indirectly, following B-cell receptor (BCR) engagement (CD4+CD39+ lymphocytes increased by 1.56 fold, in the BCR engaged samples compared to their paired controls; 20.27%±11.3 vs. 13%±9.42, respectively, p=0.0006). Conclusions: Increased CD39 expression on CD4+ T-lymphocytes in CLL associates with an aggressive disease. This may reflect the ability of the leukemic cells to suppress the surrounding immune environment, and contribute to a poorer prognosis. CD39+ may also serve as a future target for the development of novel therapies with immune modulating anti–tumor agents in CLL. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3873-3873
Author(s):  
Yangqiu Li ◽  
Qingsong Yin ◽  
Shaohua Chen ◽  
Lijian Yang ◽  
Grzegorz Przybylski ◽  
...  

Abstract Thymic recent output function is characterized its importance of thymus to T-cell diversity in the periphery of both children and adults. The generation of TCR diversity occurs in the thymus through recombination of gene segments encoding the variable parts of the TCR α and β chains. During these processes, by-products of the rearrangements are generated in the form of signal joint T-cell receptor excision circles (sjTRECs), which is considered as a very valuable tool to estimate thymic function. Quantitative of δRec-ψJα sjTRECs can direct evaluate the recent thymic output function, but it is unable to analyze the particular thymic output function of different TCR Vβ subfamily naive T cells. The complexity of TCR Vβ repertoire is an important factor for immune reconstitution, quantitative analysis of series TCR Vβ-Dβ sjTRECs could be used to evaluate the levels of different Vβ subfamily naive T cells. In the present study, quantitative analysis of δRec-ψJα sjTRECs was performed in mononuclear cells, CD3+, CD4+ and CD8+T cells from peripheral blood of normal individuals and cord blood by real-time PCR(TaqMan). And the analysis of 23 TCR Vβ-Dβ1 sjTRECs was performed by semi-nested PCR. Different amounts of DNA (corresponding to 2*105, 5*104, 1*104 and 1*103 cells respectively) from all samples were amplified to estimate the frequency of TCR Vβ-Dβ sjTRECs. The mean value of δRec-ψJα sjTRECs was detected in 4.10±3.65/1000 PBMCs, 6.37±5.28/1000 CD3+cells, 3.28±1.24/1000 CD4+cells, 4.67±3.63/1000 CD8+cells from normal individuals (n=14) and 35.59±47.56/1000 CBMC, 71.48±86.42/1000 CD3+cells, 41.02±32.9/1000 CD4+ cells, 52.05±52.32/1000 CD8+cells from cord blood (n=9) (p=0.0208, p=0.0096, p=0.0003, p=0.0026, respectively). A part of Vβ subfamily sjTRECs could be detected in all samples from cord blood (Vβ2, 3, 4, 5, 10, 13, 14, 15, 19 and 22) and peripheral blood (Vβ10, 13 and 14) at 5*104 cells level, some of Vβ subfamily sjTRECs could be detected in 1*103 cells level. The frequencies of 23 Vβ-Dβ1 sjTRECs were different at the same cellular concentration. The number of detectable Vβ subfamily sjTRECs was 22.00±0.94/2×105, 18.8±1.87/5×104, 10.40±2.99/1×104 and 0.78±1.39/1×103 CBMCs, as compared with 18.70±2.45/2×105 (p=0.002), 13.7±2.67/5×104 (p<0.001), 5.5±2.07/1×104 (p=0.001) and 0.50±0.71/1×103 (p=0.739) in PBMCs from normal individuals. Similar results were found in CD4+ and CD8+ T cells which were sorted from both CBMCs and PBMCs, the number of detectable Vβ subfamily sjTRECs was 13.90±2.38/1×104 CD4+cells, 11.5±1.96/1×104CD8+cells from cord blood and 5.6±2.68/1×104 CD4+cells (p<0.001) and 8.2±2.57/1×104CD8+cells (p>0.005) from normal individuals. The results indicate that the number of detectable sjTRECs of Vβ subfamilies and the frequencies of most Vβ-Dβ1 sjTRECs in normal PBMCs, CD4+ and CD8+T cells were obviously lower than those in cord blood. In conclusions, the results provide the base data of naïve T cells levels and thymic recent output function in cord blood and peripheral blood of normail individuals in chinese.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2670-2670
Author(s):  
Vit Prochazka ◽  
Martin Novák ◽  
Zuzana Pikalova ◽  
Tomas Papajik ◽  
Karel Indrak ◽  
...  

Abstract Abstract 2670 Background: Programmed death-1 (PD-1) and programmed death-1 ligand (PD-L) signaling pathways are involved in the functional impairment and “exhaustion” of cytotoxic CD8+ T cells in conditions such as chronic viral infection and in tumor immune evasion. The interaction of PD-1 with its ligand PD-L suppresses antitumor T cell function and indirectly stimulates Treg population. We investigated a hypothesis of whether examining PD-1 expression in peripheral T cells of patients with different lymphoma subtypes reflects tumor subtype or stage and compared results with healthy volunteers. Methods: Patients were assessed prior to their treatment or at the time of disease relapse or progression. We analyzed 5 patients with HL and 30 patients with NHL (T-cell n=6, diffuse large B-cell n=12, follicular lymphoma n=9, marginal zone lymphoma n=3). Twelve of the patients had relapsed or refractory diseases (B-NHL n=6, T-NHL n=2, HL n=4). Eleven patients (32%) had advanced (III/IV) disease stages. Data were compared with samples obtained from 12 healthy blood donors. Peripheral blood samples were stained with anti-CD3 FITC (Exbio), PD-1 (CD279) PE (BioLegend), anti-CD8 PerCP (Exbio), CD4 APC (Exbio), anti-CD25 FITC (BD), and anti-CD127 PE (BioLegend) using a lyse/no-wash protocol. Stained cells were acquired using the FACSCalibur cytometer (BD). Analysis of immunocompetent subpopulations was performed using the CellQuest Pro (BD) software. PD-1 (CD279) population was gated from CD3-positive T cells; minimal acquisition was designated as 10,000 CD3+ events. The percentage of PD-1+ cells within the live CD3+CD4+ and CD3+CD8+ populations was compared to isotype controls to establish baseline values. Absolute numbers were expressed as number of cells*10exp6 per liter. Population of Tregs was defined as CD4+/CD25int-hi / CD127low cells. Tregs were gated from CD4+ lymphocytes with minimal acquisition of 5,000 CD4+ cells. Results: Proportion of PD-1+/CD8+ of CD3+/CD8+ cells was significantly higher in patients with lymphoma than in healthy subjects: healthy volunteers (HV) 8.8%, B-NHL 16.0% (p=0.02), HL 21.8% (p<0.01), and T-NHL 30.8% (p<0.01). In absolute numbers of PD-1+/CD8+ cells, no significant difference was found when comparing healthy subjects and B-NHL: HV 0.23, B-NHL 0.56 (p=0.21), T-NHL 0.93 (p<0.01), and HL 1.51 (p<0.01). When analyzing the proportion of PD-1+/CD8+ cells according to disease phases, the highest numbers were found in patients with refractory/relapsed lymphoma as compared to patients with untreated disease and healthy subjects: HV 8.8%, untreated 14.6% (p=0.04), and relapsed 28.6% (p<0.01). Untreated patients had a significantly lower proportion of PD-1+/CD8+ cells than relapsed patients (p<0.01). Similar results were obtained with absolute numbers: HV 0.22, untreated 0.55 (p=0.03), and relapsed 1.24 (p=0.03). Untreated vs. relapsed patients p=0.05. Patients with limited disease stages had almost the same proportion of PD-1+/CD8+ lymphocytes compared to HV: HV 8.8%, limited stage 11% (p=0.21), and advanced stage 24.3% (p<0.01). In absolute numbers, HV had much less PD-1+/CD8+ cells in PB: HV 0.22, limited stage 0.49 (p<0.01), and advanced stage 0.97 (p<0.01). When analyzing the population of PD-1+/CD4+ cells, differences were only found in absolute numbers between HV (0.35) and HL (1.34; p<0.01), and between B-NHL (0.54) and HL (p=0.01). Regarding the population of Tregs, statistical differences were found between HV and B-NHL, HL or T-NHL in either relative or absolute numbers. On the other hand, there was a close correlation between absolute numbers of Tregs and PD-1+/CD4+ cells (p<0.01, correlation 0.73), and between Tregs and PD-1+/CD8+ cells (p<0.01, correlation 0.53). Conclusion: PD-1 expression in peripheral blood CD4+ and CD8+ cells is markedly different between lymphoma subtypes and compared with healthy subjects. The highest numbers of PD-1+/CD8+ are in patients with advanced lymphoma and at the time of disease relapse. This fact support the hypothesis that tumor clones actively switch effector CD8+ cells through the PD1L/PD-1 pathway into an immunotolerant state. PD-1 may be a potential marker of systemic immune dysregulation in lymphoma patients and further exploration of T cell subpopulations may define its role as a potential biomarker. Supported by grants: MSM 6198959205, LF-2012-007 and MZ ÈR IGA NT 11103. Disclosures: Prochazka: Roche: Travel grants Other.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4593-4593
Author(s):  
Marco Gobbi ◽  
Federico Caligaris-Cappio ◽  
Marco Montillo ◽  
Stephanie Vauléon ◽  
Stefan Zöllner ◽  
...  

Abstract Abstract 4593 Background NOX-A12 is a novel, potent, L-aptamer inhibitor of CXCL12/SDF-1, a chemokine which attracts and activates immune- and non-immune cells. The signaling of CXCL12 has been shown to play an important role in the pathophysiology of chronic lymphocytic leukemia (CLL), especially in the interaction of leukemic cells with their tissue microenvironment. The therapeutic concept of NOX-A12 is to inhibit such tumor-supporting pathways and thereby sensitizing the CLL cells towards chemotherapy. Methods The purpose of this phase IIa study is to evaluate the safety and efficacy of NOX-A12 in combination with background chemo-immunotherapy of bendamustine and rituximab (BR) in patients with relapsed CLL. The described study is being performed in compliance with ethical principles based on the Declaration of Helsinki and ICH-GCP guidelines. The study population was split into a pilot and expansion group. In the pilot group, 3 cohorts of 3 patients each received escalating doses of single agent NOX-A12 two weeks prior to the combined treatment of NOX-A12 and BR. Interim data from these patients are reported. Based on previous Phase I studies in healthy volunteers, pilot patients received a dose of 1, 2 or 4 mg/kg body weight (BW) single agent NOX-A12 on day -14, followed by a 2-weeks period of safety, PK and PD assessments prior to the combined treatment with NOX-A12 and BR. To date, the first cohort of the pilot group already progressed to the 2nd cycle of combined treatment. Evaluation criteria included adverse events according to CTCAE V4, flow cytometry of peripheral blood CD34+ cells and CLL cells, pharmacokinetics of NOX-A12, plasma concentration of CXCL12 and tumor response (NCI-WG 1996 criteria, updated 2008). Results To date 3 patients (age range: 58 – 65 years) have been enrolled in the pilot group of this study. They had received 1 or 2 prior therapies, but no bendamustine. Single i.v. doses of 1 mg/kg BW NOX-A12 had no clinically relevant effects on vital signs, 12-lead ECG parameters and laboratory parameters. One patient reported grade 1 pain in the lower limbs two days after treatment with NOX-A12. This event was not dose-limiting and resolved spontaneously on the same day. Flow cytometry of CD34+ cells and CLL cells (CD19+/CD5+high) showed a rapid mobilization of these cells into the peripheral blood on day 1. Interestingly, return to baseline was not complete at the last assessment on day 3 (for details see Figure 1). The NOX-A12 pharmacokinetics in these 3 patients (for concentration-time profile see Figure 2) is very comparable to healthy volunteers receiving i.v. NOX-A12, with a maximum plasma concentration of 1.52 ± 0.14 μM after 1 h (tmax) and a plasma elimination half-life of about 50 h. As seen in healthy volunteers the plasma concentration of CXCL12 increased upon NOX-A12 treatment and reached a maximum of 0.434 ± 0.076 μM at 24 to 72 h p.a. without ever approaching the plasma concentration of NOX-A12 (Figure 2). Conclusion Single i.v. doses of NOX-A12 at 1 mg/kg BW were safe and well tolerated; the maximum tolerated dose was not reached. NOX-A12 induced a long-lasting mobilization of CD34+ cells and leukemic cells in patients with relapsed CLL, consistent with a mechanism of action based on CXCL12 inhibition. Patient accrual and identification of an optimal chemosensitization regimen of NOX-A12 combined with BR is being continued. Disclosures: Vauléon: NOXXON Pharma AG: Employment. Zöllner:NOXXON Pharma AG: Employment. Dümmler:NOXXON Pharma AG: Employment. Kruschinski:NOXXON Pharma AG: Employment. Fliegert:NOXXON Pharma AG: Employment.


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