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Araki D, Chen V, Redekar N, Salisbury-Ruf C, Luo Y, Liu P, Li Y, Smith RH, Dagur P, Combs C, Larochelle A. Post-Transplant Administration of G-CSF Impedes Engraftment of Gene Edited Human Hematopoietic Stem Cells by Exacerbating the p53-Mediated DNA Damage Response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.29.547089. [PMID: 37425704 PMCID: PMC10327043 DOI: 10.1101/2023.06.29.547089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Granulocyte colony stimulating factor (G-CSF) is commonly used as adjunct treatment to hasten recovery from neutropenia following chemotherapy and autologous transplantation of hematopoietic stem and progenitor cells (HSPCs) for malignant disorders. However, the utility of G-CSF administration after ex vivo gene therapy procedures targeting human HSPCs has not been thoroughly evaluated. Here, we provide evidence that post-transplant administration of G-CSF impedes engraftment of CRISPR-Cas9 gene edited human HSPCs in xenograft models. G-CSF acts by exacerbating the p53-mediated DNA damage response triggered by Cas9- mediated DNA double-stranded breaks. Transient p53 inhibition in culture attenuates the negative impact of G-CSF on gene edited HSPC function. In contrast, post-transplant administration of G-CSF does not impair the repopulating properties of unmanipulated human HSPCs or HSPCs genetically engineered by transduction with lentiviral vectors. The potential for post-transplant G-CSF administration to aggravate HSPC toxicity associated with CRISPR-Cas9 gene editing should be considered in the design of ex vivo autologous HSPC gene editing clinical trials.
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Barrett JA, Choi J, Lakshmikanthan S, Kim YY, Greene D, Kolli P, Song TH, Choi IY, Kim YH, Lebel F. Eflapegrastim's enhancement of efficacy compared with pegfilgrastim in neutropenic rats supports potential for same-day dosing. Exp Hematol 2020; 92:51-61. [PMID: 33002567 DOI: 10.1016/j.exphem.2020.09.199] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 09/21/2020] [Accepted: 09/26/2020] [Indexed: 01/18/2023]
Abstract
Eflapegrastim (Rolontis) is a long-acting granulocyte colony-stimulating factor (G-CSF) with an IgG4 Fc fragment and short polyethylene glycol linker. Current G-CSF products are administered 24 hours after chemotherapy. The present study compares the duration of neutropenia (DN) with eflapegrastim or pegfilgrastim at 0, 2, 5, or 24 hours post chemotherapy. Eflapegrastim was evaluated by G-CSF receptor binding and bone marrow cell proliferation assays in vitro. Eflapegrastim-Fc component binding to Fcγ receptors C1q and FcRn was assessed by enzyme-linked immunosorbent assay. Neutropenia was induced in rats via intraperitoneal cyclophosphamide or docetaxel/cyclophosphamide. Rats received chemotherapy followed by vehicle, pegfilgrastim, or eflapegrastim at 2, 5, or 24 hours. The difference in DN after treatment was assessed. In vitro binding to G-CSF receptor of both agents was similar. Binding to FcRn and no binding to Fcγ receptors or C1q were observed with eflapegrastim. Studies in chemotherapy-induced neutropenic rats revealed shorter DN with eflapegrastim versus pegfilgrastim. Increased levels of G-CSF in serum and marrow were observed in groups treated with eflapegrastim versus those treated with pegfilgrastim. Although eflapegrastim and pegfilgrastim have similar in vitro binding affinity, the Fc fragment in eflapegrastim increases the uptake into bone marrow, resulting in increased therapeutic potential for chemotherapy-induced neutropenia. Eflapegrastim's greater marrow resident time provided a pharmacodynamic advantage over pegfilgrastim, translating into shortened duration of neutropenia. Our findings support eflapegrastim same-day administration with chemotherapy, warranting further evaluation in patients undergoing myelosuppressive chemotherapy.
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Affiliation(s)
| | | | | | - Yu-Yon Kim
- Hanmi Pharmaceuticals, Seoul, South Korea
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Plikusiene I, Balevicius Z, Ramanaviciene A, Talbot J, Mickiene G, Balevicius S, Stirke A, Tereshchenko A, Tamosaitis L, Zvirblis G, Ramanavicius A. Evaluation of affinity sensor response kinetics towards dimeric ligands linked with spacers of different rigidity: Immobilized recombinant granulocyte colony-stimulating factor based synthetic receptor binding with genetically engineered dimeric analyte derivatives. Biosens Bioelectron 2020; 156:112112. [PMID: 32174551 DOI: 10.1016/j.bios.2020.112112] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 02/16/2020] [Accepted: 02/18/2020] [Indexed: 10/24/2022]
Abstract
The modelling of protein-protein binding kinetics is important for the development of affinity-sensors and the prediction of signaling protein based drug efficiency. Therefore, in this research we have evaluated the binding kinetics of several genetically designed protein models: (i) three different ligands based on granulocyte colony-stimulating factor GCSF homo-dimeric derivatives linked by differed by linkers of different length and flexibility; (ii) an antibody-like receptor (GCSF-R) based on two GCSF-receptor sites immobilized to Fc domains, which are common parts of protein structures forming antibodies. Genetically engineered GCSF-R is similar to an antibody because it, like the antibody, has two binding sites, which both selectively bind with GCSF ligands. To design the affinity sensor model studied here, GCSF-R was immobilized on a thin gold layer via self-assembled monolayer conjugated with Protein-G. Binding kinetics between immobilized GCSF-R and all three different recombinant GCSF-based homo-dimeric derivatives were evaluated by total internal reflection ellipsometry. Association constants were determined by fitting mathematical models to the experimental data. It was clearly observed that both (i) affinity and (ii) binding kinetics depend on the length and flexibility of the linker that connects both domains of a GCSF-based ligand. The fastest association between immobilized GCSF-R and GCSF-based ligands was observed for ligands whose GCSF domains were interconnected by the longest and the most flexible linker. Here we present ellipsometry-based measurements and models of the interaction kinetics that advance the understanding of bidentate-receptor-based immunosensor action and enables us to predict the optimal linker structure for the design of GCSF-based medications.
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Affiliation(s)
- Ieva Plikusiene
- Laboratory of Nanotechnology, State Research Institute Center for Physical Sciences and Technology, Vilnius, Lithuania; Department of Physical Chemistry, Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko 24, Vilnius, Lithuania
| | - Zigmas Balevicius
- Laboratory of Nanotechnology, State Research Institute Center for Physical Sciences and Technology, Vilnius, Lithuania; Faculty of Electronics, Vilnius Gediminas Technical University, Naugarduko 41, 03227, Vilnius, Lithuania
| | - Almira Ramanaviciene
- NanoTechnas - Centre of Nanotechnology and Materials Science, Vilnius University, Naugarduko 24, Vilnius, Lithuania
| | - Julian Talbot
- CNRS, Laboratoire de Physique Théorique de la Matière Condensée, Sorbonne Université, France
| | - Gitana Mickiene
- Life Sciences Center, Vilnius University, Sauletekio ave. 7, 10257, Vilnius, Lithuania
| | - Saulius Balevicius
- Laboratory of Nanotechnology, State Research Institute Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Arunas Stirke
- Laboratory of Nanotechnology, State Research Institute Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Alla Tereshchenko
- Department of Physical Chemistry, Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko 24, Vilnius, Lithuania; Department of Experimental Physics, Faculty of Mathematics, Physics and Information Technologies, Odesa National I.I. Mechnikov University, Odesa, Ukraine
| | - Linas Tamosaitis
- Department of Physical Chemistry, Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko 24, Vilnius, Lithuania
| | - Gintautas Zvirblis
- Life Sciences Center, Vilnius University, Sauletekio ave. 7, 10257, Vilnius, Lithuania
| | - Arunas Ramanavicius
- Laboratory of Nanotechnology, State Research Institute Center for Physical Sciences and Technology, Vilnius, Lithuania; Department of Physical Chemistry, Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko 24, Vilnius, Lithuania.
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Schirm S, Engel C, Loibl S, Loeffler M, Scholz M. Model-based optimization of G-CSF treatment during cytotoxic chemotherapy. J Cancer Res Clin Oncol 2018; 144:343-358. [PMID: 29103159 PMCID: PMC5794835 DOI: 10.1007/s00432-017-2540-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 10/24/2017] [Indexed: 02/07/2023]
Abstract
PURPOSE Although G-CSF is widely used to prevent or ameliorate leukopenia during cytotoxic chemotherapies, its optimal use is still under debate and depends on many therapy parameters such as dosing and timing of cytotoxic drugs and G-CSF, G-CSF pharmaceuticals used and individual risk factors of patients. METHODS We integrate available biological knowledge and clinical data regarding cell kinetics of bone marrow granulopoiesis, the cytotoxic effects of chemotherapy and pharmacokinetics and pharmacodynamics of G-CSF applications (filgrastim or pegfilgrastim) into a comprehensive model. The model explains leukocyte time courses of more than 70 therapy scenarios comprising 10 different cytotoxic drugs. It is applied to develop optimized G-CSF schedules for a variety of clinical scenarios. RESULTS Clinical trial results showed validity of model predictions regarding alternative G-CSF schedules. We propose modifications of G-CSF treatment for the chemotherapies 'BEACOPP escalated' (Hodgkin's disease), 'ETC' (breast cancer), and risk-adapted schedules for 'CHOP-14' (aggressive non-Hodgkin's lymphoma in elderly patients). CONCLUSIONS We conclude that we established a model of human granulopoiesis under chemotherapy which allows predictions of yet untested G-CSF schedules, comparisons between them, and optimization of filgrastim and pegfilgrastim treatment. As a general rule of thumb, G-CSF treatment should not be started too early and patients could profit from filgrastim treatment continued until the end of the chemotherapy cycle.
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Affiliation(s)
- Sibylle Schirm
- Medical Faculty, Institute for Medical Informatics, Statistics and Epidemiology (IMISE), University of Leipzig, Haertelstraße 16-18, 04107 Leipzig, Germany
| | - Christoph Engel
- Medical Faculty, Institute for Medical Informatics, Statistics and Epidemiology (IMISE), University of Leipzig, Haertelstraße 16-18, 04107 Leipzig, Germany
| | - Sibylle Loibl
- German Breast Group, c/o GBG Forschungs GmbH, Martin-Behaim-Straße 12, 63263 Neu-Isenburg, Germany
| | - Markus Loeffler
- Medical Faculty, Institute for Medical Informatics, Statistics and Epidemiology (IMISE), University of Leipzig, Haertelstraße 16-18, 04107 Leipzig, Germany
| | - Markus Scholz
- Medical Faculty, Institute for Medical Informatics, Statistics and Epidemiology (IMISE), University of Leipzig, Haertelstraße 16-18, 04107 Leipzig, Germany
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Wu X, Nekka F, Li J. Steady-state volume of distribution of two-compartment models with simultaneous linear and saturated elimination. J Pharmacokinet Pharmacodyn 2016; 43:447-59. [PMID: 27405818 DOI: 10.1007/s10928-016-9483-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/30/2016] [Indexed: 11/25/2022]
Abstract
The model-independent estimation of physiological steady-state volume of distribution ([Formula: see text]), often referred to non-compartmental analysis (NCA), is historically based on the linear compartment model structure with central elimination. However the NCA-based steady-state volume of distribution ([Formula: see text]) cannot be generalized to more complex models. In the current paper, two-compartment models with simultaneous first-order and Michaelis-Menten elimination are considered. In particular, two indistinguishable models [Formula: see text] and [Formula: see text], both having central Michaelis-Menten elimination, while first-order elimination exclusively either from central or peripheral compartment, are studied. The model-based expressions of the steady-state volumes of distribution [Formula: see text] and their relationships to NCA-based [Formula: see text] are derived. The impact of non-linearity and peripheral elimination is explicitly delineated in the formulas. Being concerned with model identifiability and indistinguishability issues, an interval estimate of [Formula: see text] is suggested.
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Affiliation(s)
- Xiaotian Wu
- Department of Mathematics, Shanghai Maritime University, Shanghai, 201306, People's Republic of China
- Faculté de pharmacie, Université de Montréal, Montréal, QC, H3C 3J7, Canada
| | - Fahima Nekka
- Faculté de pharmacie, Université de Montréal, Montréal, QC, H3C 3J7, Canada.
- Centre de recherches mathématiques, Université de Montréal, Montréal, QC, H3C 3J7, Canada.
| | - Jun Li
- Faculté de pharmacie, Université de Montréal, Montréal, QC, H3C 3J7, Canada
- Centre de recherches mathématiques, Université de Montréal, Montréal, QC, H3C 3J7, Canada
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Arvedson T, O'Kelly J, Yang BB. Design Rationale and Development Approach for Pegfilgrastim as a Long-Acting Granulocyte Colony-Stimulating Factor. BioDrugs 2015; 29:185-98. [PMID: 25998211 PMCID: PMC4488452 DOI: 10.1007/s40259-015-0127-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Filgrastim, a recombinant methionyl human granulocyte colony-stimulating factor (G-CSF) (r-metHuG-CSF), is efficacious in stimulating neutrophil production and maturation to prevent febrile neutropenia (FN) in response to chemotherapy. Because of its relatively short circulating half-life, daily filgrastim injections are required to stimulate neutrophil recovery. In an effort to develop a long-acting form of filgrastim that was as safe and efficacious as filgrastim but had a longer in vivo residence time, a number of strategies were considered. Ultimately, fusion of filgrastim to polyethylene glycol (PEG) was selected. Following extensive analysis of conjugation chemistries as well as in vitro and in vivo characterization of a panel of PEGylated proteins, a construct containing a 20 kDa PEG moiety covalently conjugated to the N-terminus of filgrastim was chosen for advancement as pegfilgrastim. Pegfilgrastim is primarily cleared by neutrophils and neutrophil precursors (rather than the kidneys), meaning that clearance from the circulation is self-regulating and pegfilgrastim is eliminated only after neutrophils start to recover. Importantly, addition of PEG did not alter the mechanism of action and safety profile compared to filgrastim. Clinical evaluation revealed that a single 6 mg dose effectively reduces the duration of neutropenia and risk of FN in patients receiving chemotherapy. This work demonstrates the benefit of using PEGylation to generate pegfilgrastim, which allows for once-per-chemotherapy cycle administration while maintaining similar safety and efficacy profiles as those for multiple daily administration of filgrastim. Approaches that may provide advances for therapeutic agonists of G-CSF receptor are also discussed.
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Affiliation(s)
- Tara Arvedson
- Amgen Inc., 14-1-B, One Amgen Center Drive, Thousand Oaks, CA, 91320-1799, USA,
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Schirm S, Engel C, Loeffler M, Scholz M. A combined model of human erythropoiesis and granulopoiesis under growth factor and chemotherapy treatment. Theor Biol Med Model 2014; 11:24. [PMID: 24886056 PMCID: PMC4046020 DOI: 10.1186/1742-4682-11-24] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 05/16/2014] [Indexed: 12/03/2022] Open
Abstract
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.
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Affiliation(s)
- Sibylle Schirm
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Leipzig, Germany
- LIFE Research Center of Civilization Diseases, University of Leipzig, Leipzig, Germany
| | - Christoph Engel
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Leipzig, Germany
| | - Markus Loeffler
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Leipzig, Germany
| | - Markus Scholz
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Leipzig, Germany
- LIFE Research Center of Civilization Diseases, University of Leipzig, Leipzig, Germany
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Treatment of chemotherapy-induced neutropenia in a rat model by using multiple daily doses of oral administration of G-CSF-containing nanoparticles. Biomaterials 2014; 35:3641-9. [DOI: 10.1016/j.biomaterials.2014.01.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 01/08/2014] [Indexed: 02/07/2023]
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9
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Chua HL, Plett PA, Sampson CH, Katz BP, Carnathan GW, MacVittie TJ, Lenden K, Orschell CM. Survival efficacy of the PEGylated G-CSFs Maxy-G34 and neulasta in a mouse model of lethal H-ARS, and residual bone marrow damage in treated survivors. HEALTH PHYSICS 2014; 106:21-38. [PMID: 24276547 PMCID: PMC3843155 DOI: 10.1097/hp.0b013e3182a4df10] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In an effort to expand the worldwide pool of available medical countermeasures (MCM) against radiation, the PEGylated G-CSF (PEG-G-CSF) molecules Neulasta and Maxy-G34, a novel PEG-G-CSF designed for increased half-life and enhanced activity compared to Neulasta, were examined in a murine model of the Hematopoietic Syndrome of the Acute Radiation Syndrome (H-ARS), along with the lead MCM for licensure and stockpiling, G-CSF. Both PEG-G-CSFs were shown to retain significant survival efficacy when administered as a single dose 24 h post-exposure, compared to the 16 daily doses of G-CSF required for survival efficacy. Furthermore, 0.1 mg kg of either PEG-G-CSF affected survival of lethally-irradiated mice that was similar to a 10-fold higher dose. The one dose/low dose administration schedules are attractive attributes of radiation MCM given the logistical challenges of medical care in a mass casualty event. Maxy-G34-treated mice that survived H-ARS were examined for residual bone marrow damage (RBMD) up to 9 mo post-exposure. Despite differences in Sca-1 expression and cell cycle position in some hematopoietic progenitor phenotypes, Maxy-G34-treated mice exhibited the same degree of hematopoietic stem cell (HSC) insufficiency as vehicle-treated H-ARS survivors in competitive transplantation assays of 150 purified Sca-1+cKit+lin-CD150+cells. These data suggest that Maxy-G34, at the dose, schedule, and time frame examined, did not mitigate RBMD but significantly increased survival from H-ARS at one-tenth the dose previously tested, providing strong support for advanced development of Maxy-G34, as well as Neulasta, as MCM against radiation.
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Affiliation(s)
- Hui Lin Chua
- Indiana University School of Medicine, Indianapolis, IN, USA
| | - P. Artur Plett
- Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Barry P. Katz
- Indiana University School of Medicine, Indianapolis, IN, USA
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Comparison and modelling of pegylated or unpegylated G-CSF schedules in CHOP-14 regimen of elderly patients with aggressive B-cell lymphoma. Ann Hematol 2013; 92:1641-52. [DOI: 10.1007/s00277-013-1842-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 07/02/2013] [Indexed: 11/26/2022]
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11
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Schirm S, Engel C, Loeffler M, Scholz M. A biomathematical model of human erythropoiesis under erythropoietin and chemotherapy administration. PLoS One 2013; 8:e65630. [PMID: 23755260 PMCID: PMC3675041 DOI: 10.1371/journal.pone.0065630] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 04/25/2013] [Indexed: 11/19/2022] Open
Abstract
Anaemia is a common haematologic side effect of dose-dense multi-cycle cytotoxic polychemotherapy requiring erythrocyte transfusions or erythropoietin (EPO) administration. To simulate the effectiveness of different EPO application schedules, we performed both modelling of erythropoiesis under chemotherapy and pharmacokinetic and dynamic modelling of EPO applications in the framework of a single comprehensive biomathematical model. For this purpose, a cell kinetic model of bone marrow erythropoiesis was developed that is based on a set of differential compartment equations describing proliferation and maturation of erythropoietic cell stages. The system is regulated by several feedback loops comprising those mediated by EPO. We added a model of EPO absorption after injection at different sites and a pharmacokinetic model of EPO derivatives to account for the effects of external EPO applications. Chemotherapy is modelled by a transient depletion of bone marrow cell stages. Unknown model parameters were determined by fitting the predictions of the model to data sets of circulating erythrocytes, haemoglobin, haematocrit, percentage of reticulocytes or EPO serum concentrations derived from the literature or cooperating clinical study groups. Parameter fittings resulted in a good agreement of model and data. Depending on site of injection and derivative (Alfa, Beta, Delta, Darbepoetin), nine groups of EPO applications were distinguished differing in either absorption kinetics or pharmacokinetics. Finally, eight different chemotherapy protocols were modelled. The model was validated on the basis of scenarios not used for parameter fitting. Simulations were performed to analyze the impact of EPO applications on the risk of anaemia during chemotherapy. We conclude that we established a model of erythropoiesis under chemotherapy that explains a large set of time series data under EPO and chemotherapy applications. It allows predictions regarding yet untested EPO schedules. Prospective clinical studies are needed to validate model predictions and to explore the feasibility and effectiveness of the proposed schedules.
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Affiliation(s)
- Sibylle Schirm
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Leipzig, Germany.
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12
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Scholz M, Schirm S, Wetzler M, Engel C, Loeffler M. Pharmacokinetic and -dynamic modelling of G-CSF derivatives in humans. Theor Biol Med Model 2012; 9:32. [PMID: 22846180 PMCID: PMC3507764 DOI: 10.1186/1742-4682-9-32] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 06/12/2012] [Indexed: 11/17/2022] Open
Abstract
Background The human granulocyte colony-stimulating factor (G-CSF) is routinely applied to support recovery of granulopoiesis during the course of cytotoxic chemotherapies. However, optimal use of the drug is largely unknown. We showed in the past that a biomathematical compartment model of human granulopoiesis can be used to make clinically relevant predictions regarding new, yet untested chemotherapy regimen. In the present paper, we aim to extend this model by a detailed pharmacokinetic and -dynamic modelling of two commonly used G-CSF derivatives Filgrastim and Pegfilgrastim. Results Model equations are based on our physiological understanding of the drugs which are delayed absorption of G-CSF when applied to the subcutaneous tissue, dose-dependent bioavailability, unspecific first order elimination, specific elimination in dependence on granulocyte counts and reversible protein binding. Pharmacokinetic differences between Filgrastim and Pegfilgrastim were modelled as different parameter sets. Our former cell-kinetic model of granulopoiesis was essentially preserved, except for a few additional assumptions and simplifications. We assumed a delayed action of G-CSF on the bone marrow, a delayed action of chemotherapy and differences between Filgrastim and Pegfilgrastim with respect to stimulation potency of the bone marrow. Additionally, we incorporated a model of combined action of Pegfilgrastim and Filgrastim or endogenous G-CSF which interact via concurrent receptor binding. Unknown pharmacokinetic or cell-kinetic parameters were determined by fitting the predictions of the model to available datasets of G-CSF applications, chemotherapy applications or combinations of it. Data were either extracted from the literature or were received from cooperating clinical study groups. Model predictions fitted well to both, datasets used for parameter estimation and validation scenarios as well. A unique set of parameters was identified which is valid for all scenarios considered. Differences in pharmacokinetic parameter estimates between Filgrastim and Pegfilgrastim were biologically plausible throughout. Conclusion We conclude that we established a comprehensive biomathematical model to explain the dynamics of granulopoiesis under chemotherapy and applications of two different G-CSF derivatives. We aim to apply the model to a large variety of chemotherapy regimen in the future in order to optimize corresponding G-CSF schedules or to individualize G-CSF treatment according to the granulotoxic risk of a patient.
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Affiliation(s)
- Markus Scholz
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Haertelstrasse 16-18, 04107 Leipzig, Germany.
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Scholz M, Gross A, Loeffler M. A biomathematical model of human thrombopoiesis under chemotherapy. J Theor Biol 2010; 264:287-300. [PMID: 20083124 DOI: 10.1016/j.jtbi.2009.12.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 12/14/2009] [Accepted: 12/31/2009] [Indexed: 10/20/2022]
Abstract
Intensification of cytotoxic chemotherapy enhances the outcome of several malignancies but is limited by haematotoxicity. While neutropenia and anaemia can be treated with supportive growth factor applications, thrombocytopenia remains a dose-limiting side effect due to the lack of clinically approved pharmaceutical growth factors. Hence, it is necessary to assess the degree of thrombocytopenia of newly designed intensified regimens in the planning phase of a clinical trial. We present a simple ordinary differential equations model of thrombopoiesis under chemotherapy which maps the dynamics of stem cells, CFU-Mk, megakaryocytes and platelets in spleen and circulation. Major regulatory cytokine of thrombopoiesis is thrombopoietin (TPO) whose production and consumption is explicitly modelled. TPO acts by increasing the number of mitoses of CFU-Mk and increasing the mass and maturation of megakaryocytes. Chemotherapy is modelled by a drug-dose and cell-stage specific acute cell loss. Most of the cell kinetic parameters of the model were taken from literature. Parameters regarding TPO regulation and chemotherapy toxicity were estimated by fitting the predictions of the model to time series data of platelets received from large clinical data sets of patients under seven different chemotherapies. We obtained a good agreement between model and data for all scenarios. Parameter estimates were biologically plausible throughout. For validation, the model also explains data of TPO and platelet dynamics after thrombopheresis taken from literature. We used the model to make clinically relevant predictions. Regarding thrombocytopenia we estimated that the CHOP regimen for the treatment of high-grade non-Hodgkin's lymphoma can be time-intensified to a cycle duration of 12 days while the time-intensified CHOEP regimen would result in severe cumulative toxicity. We conclude that our proposed model proved validity for both, different chemotherapeutic regimens and thrombopheresis as well. It is useful to assess the thrombocytopenic risk in the planning phase of a clinical trial.
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Affiliation(s)
- Markus Scholz
- Institute for Medical Informatics, Statistics and Epidemiology, University of Leipzig, Haertelstrasse 16-18, 04107 Leipzig, Germany.
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