Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Sied Kebir is active.

Publication


Featured researches published by Sied Kebir.


Journal of Clinical Oncology | 2016

Bevacizumab Plus Irinotecan Versus Temozolomide in Newly Diagnosed O6-Methylguanine–DNA Methyltransferase Nonmethylated Glioblastoma: The Randomized GLARIUS Trial

Ulrich Herrlinger; Niklas Schäfer; Joachim P. Steinbach; Astrid Weyerbrock; Peter Hau; Roland Goldbrunner; Franziska Friedrich; Veit Rohde; Florian Ringel; Uwe Schlegel; Michael S. Sabel; Michael W. Ronellenfitsch; Martin Uhl; Jaroslaw Maciaczyk; Stefan Grau; Oliver Schnell; Mathias Hänel; Dietmar Krex; Peter Vajkoczy; Rüdiger Gerlach; Rolf-Dieter Kortmann; Maximilian Mehdorn; Jochen Tüttenberg; Regine Mayer-Steinacker; Rainer Fietkau; Stefanie Brehmer; Frederic Mack; Moritz Stuplich; Sied Kebir; Ralf Kohnen

PURPOSE In patients with newly diagnosed glioblastoma that harbors a nonmethylated O(6)-methylguanine-DNA methyltransferase promotor, standard temozolomide (TMZ) has, at best, limited efficacy. The GLARIUS trial thus explored bevacizumab plus irinotecan (BEV+IRI) as an alternative to TMZ. PATIENTS AND METHODS In this phase II, unblinded trial 182 patients in 22 centers were randomly assigned 2:1 to BEV (10 mg/kg every 2 weeks) during radiotherapy (RT) followed by maintenance BEV (10 mg/kg every 2 weeks) plus IRI(125 mg/m(2) every 2 weeks) or to daily TMZ (75 mg/m(2)) during RT followed by six courses of TMZ (150-200 mg/m(2)/d for 5 days every 4 weeks). The primary end point was the progression-free survival rate after 6 months (PFS-6). RESULTS In the modified intention-to-treat (ITT) population, PFS-6 was increased from 42.6% with TMZ (95% CI, 29.4% to 55.8%) to 79.3% with BEV+IRI (95% CI, 71.9% to 86.7%; P <.001). PFS was prolonged from a median of 5.99 months (95% CI, 2.7 to 7.3 months) to 9.7 months (95% CI, 8.7 to 10.8 months; P < .001). At progression, crossover BEV therapy was given to 81.8% of all patients who received any sort of second-line therapy in the TMZ arm. Overall survival (OS) was not different in the two arms: the median OS was 16.6 months (95% CI, 15.4 to 18.4 months) with BEV+IRI and was 17.5 months (95% CI, 15.1 to 20.5 months) with TMZ. The time course of quality of life (QOL) in six selected domains of the European Organisation for Research and Treatment of Cancer Quality-of-Life Questionnaire (QLQ) -C30 and QLQ-BN20 (which included cognitive functioning), of the Karnofsky performance score, and of the Mini Mental State Examination score was not different between the treatment arms. CONCLUSION BEV+IRI resulted in a superior PFS-6 rate and median PFS compared with TMZ. However, BEV+IRI did not improve OS, potentially because of the high crossover rate. BEV+IRI did not alter QOL compared with TMZ.


Journal of Clinical Oncology | 2016

Phase II Trial of Temsirolimus for Relapsed/Refractory Primary CNS Lymphoma

Agnieszka Korfel; Uwe Schlegel; Ulrich Herrlinger; Martin Dreyling; C.M. Schmidt; Luisa von Baumgarten; Antonio Pezzutto; Thomas Grobosch; Sied Kebir; Eckhard Thiel; Peter Martus; Philipp Kiewe

PURPOSE In this phase II study (NCT00942747), temsirolimus was tested in patients with relapsed or refractory primary CNS lymphoma (PCNSL). PATIENTS AND METHODS Immunocompetent adults with histologically confirmed PCNSL after experiencing high-dose methotrexate-based chemotherapy failure who were not eligible for or had experienced high-dose chemotherapy with autologous stem-cell transplant failure were included. The first cohort (n = 6) received 25 mg temsirolimus intravenously once per week. All consecutive patients received 75 mg intravenously once per week. RESULTS Thirty-seven eligible patients (median age, 70 years) were included whose median time since their last treatment was 3.9 months (range, 0.1 to 14.6 months). Complete response was seen in five patients (13.5%), complete response unconfirmed in three (8%), and partial response in 12 (32.4%) for an overall response rate of 54%. Median progression-free survival was 2.1 months (95% CI, 1.1 to 3.0 months). The most frequent Common Toxicity Criteria ≥ 3° adverse event was hyperglycemia in 11 (29.7%) patients, thrombocytopenia in eight (21.6%), infection in seven (19%), anemia in four (10.8%), and rash in three (8.1%). Fourteen blood/CSF pairs were collected in nine patients (10 pairs in five patients in the 25-mg cohort and four pairs in four patients in the 75-mg cohort). The mean maximum blood concentration was 292 ng/mL for temsirolimus and 37.2 ng/mL for its metabolite sirolimus in the 25-mg cohort and 484 ng/mL and 91.1 ng/mL, respectively, in the 75-mg cohort. Temsirolimus CSF concentration was 2 ng/mL in one patient in the 75-mg cohort; in all others, no drug was found in their CSF. CONCLUSION Single-agent temsirolimus at a weekly dose of 75 mg was found to be active in relapsed/refractory patients with PCNSL; however, responses were usually short lived.


Oncotarget | 2017

Unsupervised consensus cluster analysis of [18F]-fluoroethyl-L-tyrosine positron emission tomography identified textural features for the diagnosis of pseudoprogression in high-grade glioma

Sied Kebir; Zain Khurshid; Florian Gaertner; Markus Essler; Elke Hattingen; Rolf Fimmers; Björn Scheffler; Ulrich Herrlinger; Ralph Bundschuh; Martin Glas

Rationale Timely detection of pseudoprogression (PSP) is crucial for the management of patients with high-grade glioma (HGG) but remains difficult. Textural features of O-(2-[18F]fluoroethyl)-L-tyrosine positron emission tomography (FET-PET) mirror tumor uptake heterogeneity; some of them may be associated with tumor progression. Methods Fourteen patients with HGG and suspected of PSP underwent FET-PET imaging. A set of 19 conventional and textural FET-PET features were evaluated and subjected to unsupervised consensus clustering. The final diagnosis of true progression vs. PSP was based on follow-up MRI using RANO criteria. Results Three robust clusters have been identified based on 10 predominantly textural FET-PET features. None of the patients with PSP fell into cluster 2, which was associated with high values for textural FET-PET markers of uptake heterogeneity. Three out of 4 patients with PSP were assigned to cluster 3 that was largely associated with low values of textural FET-PET features. By comparison, tumor-to-normal brain ratio (TNRmax) at the optimal cutoff 2.1 was less predictive of PSP (negative predictive value 57% for detecting true progression, p=0.07 vs. 75% with cluster 3, p=0.04). Principal Conclusions Clustering based on textural O-(2-[18F]fluoroethyl)-L-tyrosine PET features may provide valuable information in assessing the elusive phenomenon of pseudoprogression.


Oncology | 2014

Carmustine (BCNU) plus Teniposide (VM26) in Recurrent Malignant Glioma

Frederic Mack; Niklas Schäfer; Sied Kebir; Moritz Stuplich; Christina Schaub; Michael Niessen; Björn Scheffler; Ulrich Herrlinger; Martin Glas

Background: After the failure of radiotherapy and temozolomide, there is no established standard therapy for patients with recurrent glioblastoma (GBM). Based on the promising data of a previous trial (NOA-01) for primary GBM and some retrospective case series for GBM recurrence, the combination of nimustine and teniposide (VM26) was commonly used in this setting. When nimustine was no longer available in Europe, we switched to intrvaveneous carmustine (BCNU). Data on the toxicity and efficacy of BCNU and VM26 in recurrent GBM are lacking. Methods: In our neurooncological center, all patients with recurrent GBM or with progressed glioma and a typical MRI lesion suggesting GBM treated with BCNU (130-150 mg/m2, day 1/42) and VM26 (45-60 mg/m2, days 1-3/42) were analyzed retrospectively for progression-free survival, overall survival and toxicity. Results: Fifteen patients (median age 52 years) were identified. Median progression-free survival was 2 months and median overall survival was 4 months. Two patients (14%) developed grade 3/4 hematotoxicity. Nonhematological toxicity ≥grade 3 was not observed. Conclusion: Our data do not support the application of BCNU/VM26 in patients with late stages of recurrent GBM.


Clinical Cancer Research | 2017

FUNCTIONAL SUBCLONE PROFILING FOR PREDICTION OF TREATMENT-INDUCED INTRA-TUMOR POPULATION SHIFTS AND DISCOVERY OF RATIONAL DRUG COMBINATIONS IN HUMAN GLIOBLASTOMA

Roman Reinartz; Shanshan Wang; Sied Kebir; Daniel J. Silver; Anja Wieland; Tong Zheng; Marius D. Kupper; Laurèl Rauschenbach; Rolf Fimmers; Timothy M. Shepherd; Daniel Trageser; Andreas Till; Niklas Schäfer; Martin Glas; Axel M. Hillmer; Sven Cichon; Amy Smith; Torsten Pietsch; Ying Liu; Brent A. Reynolds; Anthony T. Yachnis; David W. Pincus; Matthias Simon; Oliver Brüstle; Dennis A. Steindler; Björn Scheffler

Purpose: Investigation of clonal heterogeneity may be key to understanding mechanisms of therapeutic failure in human cancer. However, little is known on the consequences of therapeutic intervention on the clonal composition of solid tumors. Experimental Design: Here, we used 33 single cell–derived subclones generated from five clinical glioblastoma specimens for exploring intra- and interindividual spectra of drug resistance profiles in vitro. In a personalized setting, we explored whether differences in pharmacologic sensitivity among subclones could be employed to predict drug-dependent changes to the clonal composition of tumors. Results: Subclones from individual tumors exhibited a remarkable heterogeneity of drug resistance to a library of potential antiglioblastoma compounds. A more comprehensive intratumoral analysis revealed that stable genetic and phenotypic characteristics of coexisting subclones could be correlated with distinct drug sensitivity profiles. The data obtained from differential drug response analysis could be employed to predict clonal population shifts within the naïve parental tumor in vitro and in orthotopic xenografts. Furthermore, the value of pharmacologic profiles could be shown for establishing rational strategies for individualized secondary lines of treatment. Conclusions: Our data provide a previously unrecognized strategy for revealing functional consequences of intratumor heterogeneity by enabling predictive modeling of treatment-related subclone dynamics in human glioblastoma. Clin Cancer Res; 23(2); 562–74. ©2016 AACR.


Experimental hematology & oncology | 2012

Intravascular CNS lymphoma: Successful therapy using high-dose methotrexate-based polychemotherapy.

Sied Kebir; Klaus Kuchelmeister; Pitt Niehusmann; Michael Nelles; Young Kim; Sharmilan Thanendrarajan; Niklas Schäfer; Moritz Stuplich; Frederic Mack; Björn Scheffler; Horst Urbach; Martin Glas; Ulrich Herrlinger

Intravascular diffuse large B-cell lymphoma limited to the CNS (cIVL) is a very rare malignant disorder characterized by a selective accumulation of neoplastic lymphocytes (usually B cells) within the lumen of CNS blood vessels but not in the brain parenchyma. In the past, treatment of cIVL with anthracycline-based regimens was unsatisfactory with very short survival times. In the case of cIVL presented here, high-dose methotrexate-based polychemotherapy according to the Bonn protocol plus rituximab therapy was successful and led to a complete clinical and MRI remission which is ongoing 29 months after diagnosis.


PLOS ONE | 2015

Tlr4 Deficiency Protects against Cardiac Pressure Overload Induced Hyperinflammation.

Heidi Ehrentraut; Stefan Felix Ehrentraut; Olaf Boehm; Sakina El Aissati; Fabian Foltz; Lina Goelz; David Goertz; Sied Kebir; Christina Weisheit; Michael Wolf; Rainer Meyer; Georg Baumgarten

Transverse aortic constriction provokes a pro-inflammatory reaction and results in cardiac hypertrophy. Endogenous ligands contribute to cardiac hypertrophy via toll-like receptor (TLR)-4 binding. A lack of TLR4 signaling diminishes hypertrophy and inflammation. Wild type mice undergoing aortic constriction respond to a lipopolysaccharide second-hit stimulus with hyperinflammation. The objective of this study was to assess whether other second-hit challenges utilizing TLR ligands provoke a comparable inflammatory reaction, and to find out whether this response is absent in TLR4 deficient mice. Assuming that cardiac stress alters the expression of pattern recognition receptors we analyzed the effects of transverse aortic constriction and second-hit virulence factor treatment on TLR expression, as well as cytokine regulation. Wild type and Tlr4 -/- mice were subjected to three days of TAC and subsequently confronted with gram-positive TLR2 ligand lipoteichoic acid (LTA, 15mg/g bodyweight) or synthetic CpG-oligodesoxynucleotide 1668 thioate (20 nmol/kg bodyweight, 30 min after D-galactosamin desensitization) signaling via TLR9. Hemodynamic measurements and organ preservation were performed 6 h after stimulation. Indeed, the study revealed a robust enhancement of LTA induced pattern recognition receptor and cytokine mRNA expression and a LTA-dependent reduction of hemodynamic pressure in TAC wild type mice. Second-Hit treatment with CpG-ODNs led to similar results. However, second-hit effects were abolished in Tlr4 -/- mice. In total, these data indicate for the first time that cardiac stress increases the inflammatory response towards both, gram-negative and gram-positive, TLR ligands as well as bacterial DNA. The decrease of the inflammatory response upon TLR2 and -9 ligand challenge in TAC Tlr4 -/- mice demonstrates that a lack of TLR4 signaling does not only prevent left ventricular hypertrophy but also protects the mice from a cardiac stress induced hyperinflammatory reaction.


Neuro-oncology | 2018

Quality of life in the GLARIUS trial randomizing bevacizumab/irinotecan versus temozolomide in newly diagnosed, MGMT-nonmethylated glioblastoma

Niklas Schäfer; Martin Proescholdt; Joachim P. Steinbach; Astrid Weyerbrock; Peter Hau; Oliver Grauer; Roland Goldbrunner; Franziska Friedrich; Veit Rohde; Florian Ringel; Uwe Schlegel; Michael Sabel; Michael W. Ronellenfitsch; Martin Uhl; Stefan Grau; Mathias Hänel; Oliver Schnell; Dietmar Krex; Peter Vajkoczy; Ghazaleh Tabatabai; Frederic Mack; Christina Schaub; Theophilos Tzaridis; Michael Nießen; Sied Kebir; Barbara Leutgeb; Horst Urbach; Claus Belka; Walter Stummer; Martin Glas

Background The GLARIUS trial, which investigated the efficacy of bevacizumab (BEV)/irinotecan (IRI) compared with standard temozolomide in the first-line therapy of O6-methylguanine-DNA methyltransferase (MGMT)-nonmethylated glioblastoma, showed that progression-free survival was significantly prolonged by BEV/IRI, while overall survival was similar in both arms. The present report focuses on quality of life (QoL) and Karnofsky performance score (KPS) during the whole course of the disease. Methods Patients (n = 170) received standard radiotherapy and were randomized (2:1) for BEV/IRI or standard temozolomide. At least every 3 months KPS was determined and QoL was measured using the European Organisation for Research and Treatment of Cancer 30-item Core Quality of Life and 20-item Brain Neoplasm questionnaires. A generalized estimating equation (GEE) model evaluated differences in the course of QoL and KPS over time. Also, the time to first deterioration and the time to postprogression deterioration were analyzed separately. Results In all dimensions of QoL and KPS, GEE analyses and time to first deterioration analyses did not detect significant differences between the treatment arms. At progression, 82% of patients receiving second-line therapy in the standard arm received BEV second-line therapy. For the dimensions of motor dysfunction and headaches, time to postprogression deterioration was prolonged in the standard arm receiving crossover second-line BEV in the vast majority of patients at the time of evaluation. Conclusions GLARIUS did not find indications for a BEV-induced detrimental effect on QoL in first-line therapy of MGMT-nonmethylated GBM patients. Moreover, GLARIUS provided some indirect corroborative data supporting the notion that BEV may have beneficial effects upon QoL in relapsed GBM.


Journal of Clinical Neuroscience | 2018

Recurrent pseudoprogression in isocitrate dehydrogenase 1 mutant glioblastoma

Sied Kebir; Laurèl Rauschenbach; Gerrit H. Gielen; Niklas Schäfer; Theophilos Tzaridis; Björn Scheffler; Frank A. Giordano; Lazaros Lazaridis; Ulrich Herrlinger; Martin Glas

In a subset of glioblastoma (GBM) patients, the differentiation between tumor progression and tumor pseudoprogression (PsP) is challenging. This case describes a male patient suffering from isocitrate dehydrogenase 1 (IDH1) mutant GBM who demonstrated an increasing contrast-enhancing (CE) lesion on a cranial magnetic resonance imaging (cMRI) scan 8 months after radiochemotherapy. In accordance with the response assessment in neuro-oncology (RANO) criteria, the cMRI lesion was classified as recurrent tumor, although 18F-fluoroethyl-L-tyrosine positron emission tomography (18F-FET-PET) did not indicate vital tumor tissue. The patient underwent re-surgery but histopathology only revealed reactive and necrotic tissue, consistent with PsP. Nine weeks after complete resection of the CE lesion, a new lesion emerged that later regressed in the follow-up cMRI scans, thereby retrospectively establishing the diagnosis of recurrent PsP.


Journal of Cancer Research and Clinical Oncology | 2018

Tumor growth patterns of MGMT-non-methylated glioblastoma in the randomized GLARIUS trial

Christina Schaub; Sied Kebir; Nina Junold; Elke Hattingen; Niklas Schäfer; Joachim P. Steinbach; Astrid Weyerbrock; Peter Hau; Roland Goldbrunner; Michael Niessen; Frederic Mack; Moritz Stuplich; Theophilos Tzaridis; Oliver Bähr; Rolf-Dieter Kortmann; Uwe Schlegel; Friederike Schmidt-Graf; Veit Rohde; Christian Braun; Mathias Hänel; Michael Sabel; Rüdiger Gerlach; Dietmar Krex; Claus Belka; Hartmut Vatter; Martin Proescholdt; Ulrich Herrlinger; Martin Glas

BackgroundWe evaluated patterns of tumor growth in patients with newly diagnosed MGMT-non-methylated glioblastoma who were assigned to undergo radiotherapy in conjunction with bevacizumab/irinotecan (BEV/IRI) or standard temozolomide (TMZ) within the randomized phase II GLARIUS trial.MethodsIn 142 patients (94 BEV/IRI, 48 TMZ), we reviewed magnetic resonance imaging scans at baseline and first tumor recurrence. Based on contrast-enhanced T1-weighted and fluid-attenuated inversion recovery images, we assessed tumor growth patterns and tumor invasiveness. Tumor growth patterns were classified as either multifocal or local at baseline and recurrence; at first recurrence, we additionally assessed whether distant lesions appeared. Invasiveness was determined as either diffuse or non-diffuse. Associations with treatment arms were calculated using Fisher’s exact test.ResultsAt baseline, 115 of 142 evaluable patients (81%) had a locally confined tumor. Between treatment arms, there was no significant difference in the fraction of tumors that changed from an initially local tumor growth pattern to a multifocal pattern (12 and 13%, p = 0.55). Distant lesions appeared in 17% (BEV/IRI) and 13% (TMZ) of patients (p = 0.69). 15% of patients in the BEV/IRI arm and 8% in the TMZ arm developed a diffuse growth pattern from an initially non-diffuse pattern (p = 0.42).ConclusionsThe tumor growth and invasiveness patterns do not differ between BEV/IRI and TMZ-treated MGMT-non-methylated glioblastoma patients in the GLARIUS trial. BEV/IRI was not associated with an increased rate of multifocal, distant, or highly invasive tumors at the time of recurrence.

Collaboration


Dive into the Sied Kebir's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Peter Hau

University of Regensburg

View shared research outputs
Researchain Logo
Decentralizing Knowledge