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65 Publications visible to you, out of a total of 65
A combined model of human erythropoiesis and granulopoiesis under growth factor and chemotherapy treatment.
HaematoSys - Systems biology of haematopoiesis and haematopoietic neoplasia

Abstract (Expand)

BACKGROUND: Haematotoxicity of conventional chemotherapies often results in delays of treatment or reduction of chemotherapy dose. To ameliorate these side-effects, patients are routinely treated with … blood transfusions or haematopoietic growth factors such as erythropoietin (EPO) or granulocyte colony-stimulating factor (G-CSF). For the latter ones, pharmaceutical derivatives are available, which differ in absorption kinetics, pharmacokinetic and -dynamic properties. Due to the complex interaction of cytotoxic effects of chemotherapy and the stimulating effects of different growth factor derivatives, optimal treatment is a non-trivial task. In the past, we developed mathematical models of thrombopoiesis, granulopoiesis and erythropoiesis under chemotherapy and growth-factor applications which can be used to perform clinically relevant predictions regarding the feasibility of chemotherapy schedules and cytopenia prophylaxis with haematopoietic growth factors. However, interactions of lineages and growth-factors were ignored so far. RESULTS: To close this gap, we constructed a hybrid model of human granulopoiesis and erythropoiesis under conventional chemotherapy, G-CSF and EPO applications. This was achieved by combining our single lineage models of human erythropoiesis and granulopoiesis with a common stem cell model. G-CSF effects on erythropoiesis were also implemented. Pharmacodynamic models are based on ordinary differential equations describing proliferation and maturation of haematopoietic cells. The system is regulated by feedback loops partly mediated by endogenous and exogenous EPO and G-CSF. Chemotherapy is modelled by depletion of cells. Unknown model parameters were determined by fitting the model predictions to time series data of blood counts and cytokine profiles. Data were extracted from literature or received from cooperating clinical study groups. Our model explains dynamics of mature blood cells and cytokines after growth-factor applications in healthy volunteers. Moreover, we modelled 15 different chemotherapeutic drugs by estimating their bone marrow toxicity. Taking into account different growth-factor schedules, this adds up to 33 different chemotherapy regimens explained by the model. CONCLUSIONS: We conclude that we established a comprehensive biomathematical model to explain the dynamics of granulopoiesis and erythropoiesis under combined chemotherapy, G-CSF, and EPO applications. We demonstrate how it can be used to make predictions regarding haematotoxicity of yet untested chemotherapy and growth-factor schedules.

Authors: S. Schirm, C. Engel, M. Loeffler, M. Scholz

Date Published: 26th May 2014

Publication Type: Not specified

Human Diseases: leukemia, anemia

Role of radiotherapy to bulky disease in elderly patients with aggressive B-cell lymphoma.
GLA - German Lymphoma Alliance

Abstract (Expand)

PURPOSE: R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone) is standard care for aggressive B-cell lymphoma. A prospective trial was conducted to investigate the role … of additive radiotherapy (RT) to bulky and extralymphatic disease. PATIENTS AND METHODS: The best arm of the RICOVER-60 trial (6xR-CHOP-14+2R [R-CHOP administered once every 2 weeks plus two additional applications of rituximab] plus involved-field RT [36 Gy] to sites of initial bulky [>/= 7.5 cm] disease and extralymphatic involvement) was compared with a cohort receiving the same immunochemotherapy but without RT in an amendment to the RICOVER-60 trial (RICOVER-noRTh) in a prospective fashion. RESULTS: After a median observation time of 39 months, 164 of 166 RICOVER-noRTh patients were evaluable. In a multivariable analysis of the intention-to-treat population adjusting for International Prognostic Index risk factors and age (> 70 years), event-free survival (EFS) of patients with bulky disease was inferior without additive RT (hazard ratio [HR], 2.1; 95% CI, 1.3 to 3.5; P = .005), with trends for inferior progression-free (PFS; HR, 1.8; 95% CI, 1.0 to 3.3; P = .058) and overall survival (OS; HR, 1.6; 95% CI, 0.9 to 3.1; P = .127). In a per-protocol analysis with 11 patients in RICOVER-noRTh excluded for receiving unplanned RT, multivariable analysis revealed HRs of 2.7 (95% CI, 1.3 to 5.9; P = .011) for EFS, 4.4 (95% CI, 1.8 to 10.6; P = .001) for PFS, and 4.3 (95% CI, 1.7 to 11.1; P = .002) for OS for patients not receiving RT to bulky disease. CONCLUSION: Additive RT to bulky sites abrogates bulky disease as a risk factor and improves outcome of elderly patients with aggressive B-cell lymphoma. Whether RT can be spared in patients with (metabolic) complete remission after immunochemotherapy must be addressed in appropriately designed prospective trials.

Authors: G. Held, N. Murawski, M. Ziepert, J. Fleckenstein, V. Poschel, C. Zwick, J. Bittenbring, M. Hanel, S. Wilhelm, J. Schubert, N. Schmitz, M. Loffler, C. Rube, M. Pfreundschuh

Date Published: 10th Apr 2014

Publication Type: Not specified

Human Diseases: non-Hodgkin lymphoma

Populational equilibrium through exosome-mediated Wnt signaling in tumor progression of diffuse large B-cell lymphoma.
GLA - German Lymphoma Alliance

Abstract (Expand)

Tumors are composed of phenotypically heterogeneous cell populations. The nongenomic mechanisms underlying transitions and interactions between cell populations are largely unknown. Here, we show that … diffuse large B-cell lymphomas possess a self-organized infrastructure comprising side population (SP) and non-SP cells, where transitions between clonogenic states are modulated by exosome-mediated Wnt signaling. DNA methylation modulated SP-non-SP transitions and was correlated with the reciprocal expressions of Wnt signaling pathway agonist Wnt3a in SP cells and the antagonist secreted frizzled-related protein 4 in non-SP cells. Lymphoma SP cells exhibited autonomous clonogenicity and exported Wnt3a via exosomes to neighboring cells, thus modulating population equilibrium in the tumor.

Authors: R. Koch, M. Demant, T. Aung, N. Diering, A. Cicholas, B. Chapuy, D. Wenzel, M. Lahmann, A. Guntsch, C. Kiecke, S. Becker, T. Hupfeld, V. Venkataramani, M. Ziepert, L. Opitz, W. Klapper, L. Trumper, G. G. Wulf

Date Published: 3rd Apr 2014

Publication Type: Not specified

Human Diseases: diffuse large B-cell lymphoma

Parenthood in long-term survivors after CHOP with or without etoposide treatment for aggressive lymphoma.
GLA - German Lymphoma Alliance

Abstract

Not specified

Authors: J. Meissner, D. Tichy, S. Dietrich, T. Schmitt, M. Ziepert, E. Kuhnt, T. Rixecker, M. Witzens-Harig, M. Pfreundschuh, A. D. Ho

Date Published: 3rd Apr 2014

Publication Type: Not specified

Human Diseases: lymphoma

Suboptimal dosing of rituximab in male and female patients with DLBCL.
GLA - German Lymphoma Alliance

Abstract (Expand)

To determine the effect of gender on outcome, the male hazard ratio for progression-free survival (HRPFS-male) was determined in patients with diffuse large B-cell lymphoma (DLBCL). In young patients … (MapThera International Trial study), HRPFS-male was 1.3 (P = .092) without and 1.1 (P = .660) with rituximab. In elderly patients (RICOVER-60 study), HRPFS-male was 1.1 (P = .348) with CHOP but increased to 1.6 (P = .004) with R-CHOP. The similar improvements of outcome in young patients were associated with similar rituximab clearances in young males and females (9.89 vs 10.38 mL/h; P = .238), whereas the greater benefit for elderly females was associated with a slower rituximab clearance (8.47 vs 10.59 mL/h; P = .005) and hence higher serum levels and longer exposure times, attributable to an age-dependent (P = .004) decrease of rituximab clearance in females but not males. Compared with elderly females, all other subgroups had significantly faster rituximab clearances and hence appear to be suboptimally dosed when rituximab is given at 375 mg/m(2). Although early results of pharmacokinetic-based prospective trials designed to exploit the full therapeutic potential of rituximab suggest that increased doses and/or prolonged exposure times can improve the outcome of elderly males with DLBCL, further studies are warranted that address the optimization of rituximab dose and schedule in all subgroups of DLBCL patients.

Authors: M. Pfreundschuh, C. Muller, S. Zeynalova, E. Kuhnt, M. H. Wiesen, G. Held, T. Rixecker, V. Poeschel, C. Zwick, M. Reiser, N. Schmitz, N. Murawski

Date Published: 30th Jan 2014

Publication Type: Not specified

Human Diseases: diffuse large B-cell lymphoma

Significant dose Escalation of Idarubicin in the treatment of aggressive Non- Hodgkin Lymphoma leads to increased hematotoxicity without improvement in efficacy in comparison to standard CHOEP-14: 9-year follow up results of the CIVEP trial of the DSHNHL.
GLA - German Lymphoma Alliance

Abstract (Expand)

BACKGROUND: Dose escalation and modification of CHOP has improved the prognosis of patients with aggressive lymphoma; even in the rituximab era, dose escalation for high-risk patients is exploited and … frequently limited by drug toxicity. Idarubicin (Id) is a 4-demethoxy anthracycline analogue of daunorubicin with activity against lymphoma and has been reported to cause less cardiotoxicity than other anthracylines. The aim of this study was to replace doxorubicine with idarubicin in the CHOEP regimen and to find the maximum tolerable dose (MTD) of idarubicin based on hematotoxicity. PATIENTS AND METHODS: Between 11/96 and 09/98, 64 patients (pts) aged 18-75 yrs (pts. 18-60, LDH not elevated, >60 years all risk groups) with newly diagnosed aggressive lymphoma received 6 cycles of CIVEP-14 with an escalating dose of idarubicin, consisting of idarubicin (11-16 mg/m(2) d1) and standard doses of cyclophosphamide, vincristine, etoposide, and prednisone with G-CSF support. RESULTS: 55 pts (median age 56 yrs) were evaluable for a final analysis with a median observation time of 9.3 years. The CR-rate was 77.4% ; the 5 and 8-year-EFS rates were 46.4% (95%CI 32.5-60.3%) and 43.5% (29.4-57.6%), respectively, and the 5- and 8 yr OS rates were 64.6% (51.7-77.5%) and 59.9% (46.4-73.4%). 14/55 patients have died due to lymphoma progression, and 2/55 patients (3.6%) due to treatment related toxicity, 4/55 due to other causes (3 infections, 1 acute heart failure). In a matched pair analysis comparing CHOEP-14 and CIVEP-14, CIVEP-14 had a higher hematotoxicity with no significant differences in the event free and overall survival for the two regimens. CONCLUSIONS: Thus, idarubicin cannot be used instead doxorubicin even if its dose is escalated to achieve similar hematotoxicity. Doxorubicin remains the standard anthracycline for the treatment of aggressive NHL.

Authors: K. Hohloch, C. Zwick, M. Ziepert, D. Hasenclever, U. Kaiser, A. Engert, H. G. Hoffkes, F. Kroschinsky, R. Mesters, A. C. Feller, M. Loffler, L. Trumper, M. Pfreundschuh

Date Published: 3rd Jan 2014

Publication Type: Not specified

Human Diseases: non-Hodgkin lymphoma

Impact of rituximab and radiotherapy on outcome of patients with aggressive B-cell lymphoma and skeletal involvement.
GLA - German Lymphoma Alliance

Abstract (Expand)

PURPOSE: To study clinical presentation, outcome, and the role of radiotherapy in patients with aggressive B-cell lymphoma and skeletal involvement treated with and without rituximab. PATIENTS AND … METHODS: Outcome of patients with skeletal involvement was analyzed in a retrospective study of nine consecutive prospective trials of the German High-Grade Non-Hodgkin lymphoma Study Group. RESULTS: Of 3,840 patients, 292 (7.6%) had skeletal involvement. In the MabThera International Trial (MInT) for young good-prognosis patients and the Rituximab With CHOP Over 60 Years (RICOVER-60) study for elderly patients, the randomized addition of rituximab improved event-free survival (EFS; hazard ratio for MInT [HRMInT] = 0.4, P > 001; hazard ratio for RICOVER-60 [HRRICOVER-60] = 0.6, P > .001) and overall survival (OS; HRMInT = 0.4, P < .001; HRRICOVER-60 = 0.7, P = .002) in patients without skeletal involvement, but failed to improve the outcome of patients with skeletal involvement (EFS: HRMInT = 1.4, P = .444; HRRICOVER-60 = 0.8, P = .449; OS: HRMInT = 0.6, P = .449; HRRICOVER-60 = 1.0, P = .935). Skeletal involvement was associated with a worse outcome after cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus rituximab (HREFS = 1.5, P = .048; HROS = 1.1; P = .828), but not after CHOP without rituximab (HREFS = 0.8, P = .181; HROS = 0.7, P = .083). In contrast to rituximab, additive radiotherapy to sites of skeletal involvement was associated with a decreased risk (HREFS = 0.3, P = .001; HROS = 0.5; P = .111). CONCLUSION: Rituximab failed to improve the outcome of patients with diffuse large B-cell lymphoma with skeletal involvement, although our data suggest a beneficial effect of radiotherapy to sites of skeletal involvement. Whether radiotherapy to sites of skeletal involvement can be spared in cases with a negative positron emission tomography after immunochemotherapy should be addressed in appropriately designed prospective trials.

Authors: G. Held, S. Zeynalova, N. Murawski, M. Ziepert, B. Kempf, A. Viardot, M. Dreyling, M. Hallek, M. Witzens-Harig, J. Fleckenstein, C. Rube, C. Zwick, B. Glass, N. Schmitz, M. Pfreundschuh

Date Published: 10th Nov 2013

Publication Type: Not specified

Human Diseases: B-cell lymphoma

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