Anders Toft

Angiotensinogen and HLA class II predict bevacizumab response in recurrent glioblastoma patients

Bevacizumab combination therapy is among the most frequently used treatments in recurrent glioblastoma and patients who achieve response to bevacizumab have improved survival as well as quality of life. Accordingly, the aim of this study was to identify predictive biomarkers for bevacizumab response in recurrent glioblastoma patients.

Development and validation of a prognostic model for recurrent glioblastoma patients treated with bevacizumab and irinotecan

Abstract Background Predictive markers and prognostic models are required in order to individualize treatment of recurrent glioblastoma (GBM) patients. Here, we sought to identify clinical factors able to predict response and survival in recurrent GBM patients treated with bevacizumab (BEV) and irinotecan. Material and methods A total of 219 recurrent GBM patients treated with BEV plus irinotecan according to a previously published treatment protocol were included in the initial population. Prognostic models were generated by means of multivariate logistic and Cox regression analysis. Results In multivariate analysis, corticosteroid use had a negative predictive impact on response at first evaluation (OR 0.45; 95% CI 0.22–0.93; pu2009=u20090.03) and at best response (OR 0.51; 95% CI 0.26–1.02; pu2009=u20090.056). Three significant (pu2009<u20090.05) prognostic factors associated with reduced progression-free survival and overall survival (OS) were identified. These factors were included in the final model for OS, namely corticosteroid use (HR 1.70; 95% CI 1.18–2.45; pu2009=u20090.004), neurocognitive deficit (HR 1.40; 95% CI 1.04–1.89; pu2009=u20090.03) and multifocal disease (HR 1.56; 95% CI 1.15–2.11; pu2009<u20090.0001). Based on these results a prognostic index able to calculate the probability for OS at 6 and 12 months for the individual patient was established. The predictive value of the model for OS was validated in a separate patient cohort of 85 patients. Discussion and conclusion A prognostic model for OS was established and validated. This model can be used by physicians to risk stratify the individual patient and together with the patient decide whether to initiate BEV relapse treatment.

Biomarkers in Recurrent Grade III Glioma Patients Treated with Bevacizumab and Irinotecan

ABSTRACT Predictive biomarkers and prognostic models are required to identify recurrent grade III glioma patients who benefit from existing treatment. In this study of 62 recurrent grade III glioma patients, a range of clinical and paraclinical factors are tested for association with progression-free survival, overall survival, and response to bevacizumab and irinotecan therapy. Significant factors from univariate screening are included in multivariate analysis. Biomarkers previously advanced as predictive or prognostic in the first-line setting did not affect outcome in this patient cohort. Based on the optimized model for overall survival, comprising performance status and p53 expression, a prognostic index is established.

Transcriptional changes induced by bevacizumab combination therapy in responding and non-responding recurrent glioblastoma patients

BackgroundBevacizumab combined with chemotherapy produces clinical durable response in 25–30% of recurrent glioblastoma patients. This group of patients has shown improved survival and quality of life. The aim of this study was to investigate changes in gene expression associated with response and resistance to bevacizumab combination therapy.MethodsRecurrent glioblastoma patients who had biomarker-accessible tumor tissue surgically removed both before bevacizumab treatment and at time of progression were included. Patients were grouped into responders (nxa0=xa07) and non-responders (nxa0=xa014). Gene expression profiling of formalin-fixed paraffin-embedded tumor tissue was performed using RNA-sequencing.ResultsBy comparing pretreatment samples of responders with those of non-responders no significant difference was observed. In a paired comparison analysis of pre- and posttreatment samples of non-responders 1 gene was significantly differentially expressed. In responders, this approach revealed 256 significantly differentially expressed genes (72 down- and 184 up-regulated genes at the time of progression). Genes differentially expressed in responders revealed a shift towards a more proneural and less mesenchymal phenotype at the time of progression.ConclusionsBevacizumab combination treatment demonstrated a significant impact on the transcriptional changes in responders; but only minimal changes in non-responders. This suggests that non-responding glioblastomas progress chaotically without following distinct gene expression changes while responding tumors adaptively respond or progress by means of the same transcriptional changes. In conclusion, we hypothesize that the identified gene expression changes of responding tumors are associated to bevacizumab response or resistance mechanisms.

Abstract A25: Predictive biomarkers for bevacizumab response in recurrent glioblastoma patients

BACKGROUND: Bevacizumab (BEV) plus chemotherapy has shown high response rates in recurrent glioblastoma (GBM) and patients who achieve response have an improved overall survival as well as quality of life. Recent retrospective analysis of the randomized phase III trial, AVAglio, indicate that patients with the proneural GBM subtype have a survival benefit when treated with BEV in combination with standard treatment. However, no validated biomarkers able to predict BEV response have been identified and the biology reflecting a clinical BEV response is poorly understood. The primary objective of this study was to evaluate the predictive and prognostic value of GBM subtypes in recurrent GBM patients treated with BEV therapy. The secondary objective was to identify biomarkers able to predict response to BEV therapy in recurrent GBM patients. METHODS: A total of 90 recurrent GBM patients treated with BEV combination treatment according to a previously published treatment protocol were included. Inclusion criteria: BEV plus irinotecan treatment in the period between May 2005-2011; available GBM tissue (according to WHO); response evaluable (RANO). RNA from tumor tissue was analyzed by the NanoString platform covering 800 genes. Raw data was assigned to molecular subtypes for each of the samples using the PAMR classifier model, previously trained on the AVAglio dataset. In order to identify novel candidate biomarkers able to predict response, differentially expressed genes (fold-change difference > 1.5) between patients responding versus progressing on BEV were identified using a t-test. Biomarkers significantly (P Citation Format: Thomas Urup, Signe Regner Michaelsen, Lars Ronn Olsen, Anders Toft, Ib Jarle Christensen, Kirsten Grunnet, Helle Broholm, Michael Kosteljanetz, Shohreh Issazadeh-Navikas, Hans Skovgaard Poulsen, Ulriik Lassen. Predictive biomarkers for bevacizumab response in recurrent glioblastoma patients. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A25.

Abstract B3: Prognostic and predictive biomarkers in recurrent WHO grade 3 malignant glioma patients treated with bevacizumab and irinotecan

BACKGROUND Bevacizumab, a monoclonal antibody targeting vascular endothelial growth factor A (VEGF-A), has demonstrated activity in the treatment of recurrent malignant glioma. High response rates have been observed, but particularly in WHO grade 3 gliomas, efforts to identify predictors of clinical response have been limited. Predictive markers and prognostic models are required in order to individualize treatment for this patient population. The primary endpoint of this study was to identify predictive biomarkers associated with response to bevacizumab therapy. The secondary endpoint was to identify prognostic factors associated with progression-free survival (PFS) and overall survival (OS). METHODS A total of 62 consecutive, recurrent grade 3 glioma patients were retrospectively evaluated. Eligible patients from our center had a WHO performance status of 0-2 and were administered bevacizumab and irinotecan between December 2005 and November 2014 according to a previously published clinical protocol. Baseline factors screened for potential prognostic and predictive value included: Age, gender, PS, WHO grade 3 diagnosis, tumor size and location, multifocal disease, extent of resection, number of prior chemotherapy regiments, response to prior chemotherapy, first-line treatment, number of previous recurrences, neurological deficit, corticosteroid use, necrosis, vascular proliferation, neutrophil-to-lymphocyte ratio, and expression of p53, EGFR, MIB-1, MGMT, IDH1 and ATRX. Candidate factors with p-values below 5% were considered for multivariate analysis. Prognostic models were generated by logistic regression and Cox regression, modelling response and survival endpoints. RESULTS Twenty-two patients (35.5%) demonstrated a response according to the RANO criteria. Responders had significantly prolonged OS (p = 0.007) and trended toward longer PFS (p = 0.067) as compared to non-responders (OS: 12.4 vs 4.3 months, PFS: 5.6 vs 3.2 months). Presence of necrosis (OR: 0.17, CI: 0.04-0.68, p = 0.012) and a WHO performance status (PS) of more than 1 (OR: 0.04, CI: 0.002-0.89, p = 0.042) were more common in non-responders than responders. Female gender (HR: 0.48, CI: 0.28-0.82, p = 0.008) and a PS of 0-1 (HR: 0.20, CI: 0.10-0.41, p CONCLUSIONS A favorable baseline PS and absence of necrosis were positively associated with response to bevacizumab treatment in recurrent grade 3 glioma patients. Low PS, female gender and p53 negativity are prognostic of improved outcome in this patient group. Citation Format: Anders Toft, Thomas Urup, Ib J. Christensen, Signe R. Michaelsen, Babloo S. Lukram, Kirsten Grunnet, Michael Kosteljanetz, Vibeke A. Larsen, Ulrik Lassen, Helle Broholm, Hans S. Poulsen. Prognostic and predictive biomarkers in recurrent WHO grade 3 malignant glioma patients treated with bevacizumab and irinotecan. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B3.

Abstract 4306: A prognostic model for clinical response to bevacizumab in recurrent glioblastoma multiforme

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PAnnBackground: Recurrent glioblastoma multiforme (GBM) is an aggressive and deadly disease with limited treatment options. In responding patients bevacizumab-containing therapy prolongs survival and improves quality of life, although the beneficial effect varies greatly. The impact of prognostic factors in recurrent GBM patients has not been studied in detail and results are inconsistent. More importantly, no validated predictive baseline markers associated with a clinical response to bevacizumab therapy have been identified. Furthermore, GBM is a very heterogenic tumor and has been shown to change molecular pattern with time and as a result of treatment. The primary goal of this study was to describe molecular characteristics in GBM tumors at initial diagnosis and at recurrence and relate these data, including clinical baseline factors, to clinical outcome with the aim of identifying predictive factors for clinical bevacizumab response. Based on these data we will also elucidate to what extent molecular markers change expression from initial GBM diagnosis to time of relapse.nnMaterials and Methods: For generation of prognostic models 219 recurrent GBM patients treated with bevacizumab plus irinotecan according to a previous published clinical protocol were included. For biomarker analysis, routine molecular analyses were available for 147 of the included patients at time of initial diagnosis and 81 patients at time of relapse prior to bevacizumab therapy. The candidate biomarkers constituted an immunohistochemistry (IHC) panel of EGFR, P53, MGMT and IDH1 and polymerase chain reaction analysis of 1p19q-status. Tumor samples from initial diagnosis and from time of relapse were analyzed by the χ2 test and the Wilcoxon test in order to evaluate changes in IHC expression patterns. Multiple candidate prognostic factors were screened by univariate logistic regression and Cox regression analysis modeling response and survival endpoints and variables with P-values of less than 0.10 were considered for multivariate analysis. Factors with a P-value of less than 0.05 in multivariate analysis were included in the prognostic models for response, progression-free survival (PFS) and overall survival (OS).nnResults: In multivariate analysis, corticosteroid use had a negative predictive impact on response at first evaluation (OR = 0.45; 95% CI: 0.22-0.93; P = 0.030) and at best response (OR = 0.51; 95% CI: 0.26-1.02; P = 0.056). Independent prognostic factors (P<0.05) negatively associated with PFS and OS were corticosteroid use, neurocognitive deficit and multifocal disease. Based on the three identified factors a prognostic model for overall survival at 6 and 12 months was developed. Significant prognostic and potentially predictive molecular biomarkers will be added to the models and results will be presented.nnCitation Format: Thomas Urup, Signe Regner Michaelsen, Camilla Bjornbak Holst, Anders Toft, Ib Jarle Christensen, Kirsten Grunnet, Michael Kosteljanetz, Helle Broholm, Ulrik Lassen, Hans Skovgaard Poulsen. A prognostic model for clinical response to bevacizumab in recurrent glioblastoma multiforme. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4306. doi:10.1158/1538-7445.AM2015-4306

Abstract 5310: Prognostic and predictive biomarkers of clinical response to Bevacizumab in recurrent WHO grade 3 malignant glioma patients

Background: Bevacizumab, a monoclonal antibody targeting vascular endothelial growth factor A (VEGF-A), has proven activity in treatment of recurrent high-grade glioma. High response rates have been demonstrated, but particularly in WHO grade 3 malignant gliomas, efforts to identify predictors of clinical response have been limited. Predictive biomarkers and prognostic models are required in order to individualize treatment for this patient population. The primary end-point of this study was identification of prognostic and potentially predictive clinical and paraclinical factors of response. The secondary end-point was to identify prognostic factors associated with progression-free survival (PFS) and overall survival (OS). Materials and methods: A total of 64 recurrent grade 3 glioma patients treated with bevacizumab and irinotecan were retrospectively evaluated. Eligible patients from our center had a WHO performance status of 0-2 and were administered bevacizumab and irinotecan between December 2005 and November 2014 according to a previously published clinical protocol. The possibly relevant prognostic baseline factors screened for included: Age, gender, WHO grade 3 diagnosis, tumor size and location, multifocal disease, extent of resection, number of prior chemotherapy regiments, response to prior chemotherapy, first-line treatment, number of previous recurrences, neurological deficit, corticosteroid use, performance status, necrosis, vascular proliferation, neutrophil-to-lymphocyte ratio, and expression of p53, EGFR, Mib-1, MGMT, IDH-1 and ATRX. Candidate factors were subjected to univariate analysis and factors with P-values below 0.10 were considered for multivariate analysis. Prognostic models were generated by logistic regression and Cox regression, modeling response and survival end-points. P-values below 0.05 were considered statistically significant. Results will be presented. Citation Format: Anders Toft, Thomas Urup, Kirsten Grunnet, Ib J. Christensen, Signe R. Michaelsen, Helle Broholm, Vibeke A. Larsen, Michael Kosteljanetz, Ulrik Lassen, Hans S. Poulsen. Prognostic and predictive biomarkers of clinical response to Bevacizumab in recurrent WHO grade 3 malignant glioma patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5310. doi:10.1158/1538-7445.AM2015-5310