Abstract 1601: Potentiation of arsenic trioxide in glioblastoma

Glioblastoma (GBM) is the most prevalent type of malignant tumor within the central nervous system. Possessing a five-year survival rate of 6.8%, new therapeutic options are a necessity in order to increase patient quality of life and survival outcomes. Arsenic trioxide (ATO) is an FDA approved drug for the treatment of relapsed or refractory acute promyelocytic leukemia. Clinical trials of ATO in combination with radiation and temozolomide show therapeutic effects in a modest subset of glioblastoma patients. ATO resistance in GBM cell lines is associated with MNK1-eIF4E upregulation. Additionally, diminished response to ATO is linked to resistance to oxidative stress via increased glutathione levels and NrF2 pathway expression. We sought to target each of these proposed mechanisms of resistance in order to develop a suite of compounds for use in combination therapies, with the goal of sensitizing GBM models to ATO. Six GBM PDX models were dosed with ATO at varying concentrations and monitored for the IC50 value of treatment. The cell lines exhibited a 20-fold difference in sensitivity, indicative of an underlying innate resistance to ATO. We performed drug dose response studies of patient-derived glioma cells treated with ATO in combination with the nutraceutical compounds Chrysin and Silibinin. Combination treatments using Chrysin and Silibinin showed potentiation of the cytotoxic effects of ATO. Confirmation of the mechanism for induced sensitivity to ATO will be explored by measuring shifts in glutathione content and susceptibility to oxidative stress in response to treatment using nutraceutical compounds. In addition, drug dosing with combination therapies utilizing the MAPK interacting serine/threonine kinase 1 (MNK1) inhibitors eFT-508 and EFT-206 also show synergistic effects in GBM cell lines. The eIF4E phosphorylation response to treatment of both ATO alone ATO MNK1i combination therapies will be monitored and analyzed for potential translational effects. Each of these compounds were selected based on safe use determined in clinical trials (MNK1 inhibitors) or over-the-counter availability (nutraceuticals). All four companion approaches show low pharmacological liabilities in crossing the blood brain barrier. Future studies involving these compounds will consist of testing these suggested combination therapies in vivo by observing their effectiveness in orthotopic, GBM tumor bearing mice. Identification and development of sensitization targets for ATO will allow for greater effectiveness of treatment and a greater potency of the drug in combating resistance which arises in response to treatment. Discovery of a predictive molecular signature of synergy from ATO and other targeted agents may pave the way for a successful clinical trial of these combinations in an identifiable subpopulation of GBM patients.

Citation Format: Charles Shaffer, Nanyun Tang, Yue Hao, Karen Fink, George Snipes, Bruce Mickey, Michael Berens. Potentiation of arsenic trioxide in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1601.

CTIM-29. PHASE 2 STUDY OF A NOVEL IMMUNOTHERAPY SL-701 IN ADULTS WITH RECURRENT GBM: IDENTIFICATION OF TREATMENT-INDUCED CD8+CD107A+ CD57+ PD-1- MEMORY T-CELLS THAT ARE ASSOCIATED WITH INCREASED SURVIVAL

Recurrent glioblastoma (GBM) is an aggressive disease with poor survival and limited treatment options. SL-701 is a novel immunotherapy comprised of synthetic peptides designed to elicit an anti-tumor immune response against GBM antigens IL-13Rα2, ephrinA2, and survivin. Here we describe an 18-color flow cytometry analysis from stage 2 of a Ph2 clinical trial of SL-701+poly-ICLC+bevacizumab (NCT02078648), in which 12-month overall survival (OS) was 50%. Of the 27 patients in stage 2, 24 (89%) developed heterogeneous T-cell responses against 1, 2, or 3 of the SL-701 CD8 peptides. Magnitude and kinetics of peptide responses were variable among these patients with no clear relationship to OS. Therefore, a phenotypic analysis of the T-cell response in all 27 patients was conducted using terraFlow, a unique data analysis approach utilizing machine learning to identify T-cell phenotypes associated with clinical response from all possible combinations of markers. In total, 10,184 unique SL-701 induced phenotypes were measured, including 223 phenotypes (P < 0.05) and 16 core phenotypes that uniquely represent differences between patients with OS above or below 12 months (P < 0.05). 50% of the core phenotypes were CD8+ CD57+ CD107a+ PD-1- SL-701-specific T-cells, which are highly-differentiated memory T-cells primed for cytotoxicity. The frequency of the CD57+ core phenotypes (8%-18%) was enhanced 1.6- to 2.3-fold in patients with an OS > 12 months (P < 0.05). Similarly, 2 core phenotypes identified cytotoxic CD4+ and CD8+ T cells, which were enhanced 1.9- and 2.5-fold in patients with an OS >12 months. The final 6 core phenotypes identified activated CD4+ CD154+ SL-701-specific T-cells (5%-19%) that were enhanced 0.3- to 0.5-fold in patients with an OS < 12 months (P < 0.05), suggesting helper T-cell responses in the absence of cytotoxic T-cell responses are associated with an OS < 12 months. Deep sequencing of SL-701-specific T-cells using whole transcriptome-based molecular cytometry is planned.

CTIM-27. AUTOLOGOUS TUMOR LYSATE-LOADED DENDRITIC CELL VACCINATION IMPROVES SURVIVAL IN PATIENTS WITH NEWLY DIAGNOSED AND RECURRENT GLIOBLASTOMA: SURVIVAL RESULTS FROM A PHASE 3 TRIAL

BACKGROUND

Standard of care (SOC) and patient survival in glioblastoma have changed little in the past 17 years. We evaluated in a phase 3 trial whether adding an autologous tumor lysate-loaded dendritic cell vaccine (murcidencel) to SOC extends survival. Patients and

METHODS

Newly diagnosed glioblastoma patients were randomized 2:1 to either murcidencel or placebo. Under a crossover design, all patients could receive murcidencel following tumor recurrence. All parties remained blinded regarding treatments before recurrence. Patients thus received murcidencel at new diagnosis (nGBM) or at recurrence (rGBM) following crossover from placebo. The primary and secondary endpoints compare overall survival (OS) with contemporaneous, matched external controls. Four sets of analyses were conducted to ensure rigorous matching of the controls, reduce biases, and confirm the robustness of the results.

RESULTS

331 patients were enrolled. With the crossover, 89% received murcidencel. Median OS (mOS) for nGBM patients (n = 232) was 19.3 months from randomization (22.4 months from surgery) with murcidencel vs. 16.5 months from randomization in the controls (HR = 0.80, p = 0.002). Survival at 48 months from randomization was 15.7% vs. 9.9%, and at 60 months was 13% vs. 5.7%. For rGBM (n = 64), mOS was 13.2 months from relapse vs. 7.8 months in the controls (HR = 0.58, p < 0.001). Survival at 24 months post-recurrence was 20.7% vs. 9.6%, and at 30 months post-recurrence was 11.1% vs 5.1%. In nGBM patients with methylated MGMT (n = 90), mOS was 30.2 months from randomization (33 months from surgery) with murcidencel vs. 21.3 months from randomization in the controls (HR = 0.74, p = 0.027). The treatment was well tolerated, with only 5 serious adverse events deemed at least possibly related to the vaccine.

CONCLUSION

Clinically meaningful and statistically significant survival extension was seen in both nGBM and rGBM patients treated with murcidencel and SOC compared with contemporaneous, matched external controls who received SOC alone.

NCOG-12. COGNITIVE FUNCTION (CF) & QUALITY OF LIFE (QOL) IN PATIENTS TREATED WITH PROCARBAZINE, CCNU, & VINCRISTINE (PCV) + RADIOTHERAPY (RT) VS. RT FOR ANAPLASTIC OLIGODENDROGLIOMA (AO) ON NRG RTOG TRIAL 9402

BACKGROUND

PCV+RT substantially prolongs survival in AO patients, but long-term CF and QOL implications are unclear. We compared CF and QOL by treatment arm in RTOG 9402 participants and evaluated the impact that baseline characteristics had on CF, QOL, and survival.

METHODS

CF and QOL were evaluated using the Mini Mental State Exam (MMSE) and Brain-Quality of Life (B-QOL) scale at baseline and annually. Scores were analyzed between treatment arms at each time point for patients with ≥ 10 years of follow-up data. Shared parameter models evaluated MMSE and B-QOL scores and survival for all patients.

RESULTS

42/148 (28.4%) participants in PCV+RT and 20/143 (14%) in RT alone arms survived ≥ 10 years. 35/42 and 39/42 (PCV+RT) and 18/20 and 17/20 (RT) participants completed baseline B-QOL and MMSE assessments, respectively. B-QOL scores did not differ between treatment groups at any time-point. Among 16 patients (10 PCV+RT, 6 RT) who completed year 10 MMSE evaluations, mean MMSE score at 10 years was higher in the RT arm (29.83 [95% CI 22.1, 30.0] vs. 26.50 [95% CI 29.4, 30.0], P= 0.04). Change in MMSE and B-QOL scores from baseline did not differ significantly between treatment groups at any time. In shared parameter models including all patients with baseline assessments, MMSE and B-QOL scores decreased over time (MMSE P= 0.0189, B-QOL P= 0.0005), but this did not differ by treatment group (MMSE P= 0.5727, B-QOL P= 0.3592). Younger age and higher KPS predicted better scores (MMSE P < 0.0001, P = 0.0002; B-QOL P = 0.0043, P = 0.0007). PCV+RT predicted better survival in both models.

CONCLUSIONS

PCV+RT improves survival in AO. Shared parameter models show decrease in MMSE and B-QOL over time. However, relative to RT alone, the addition of PCV did not impact change in CF and QOL over time.

CTIM-11. PHASE 2 STUDY OF SL-701, A NOVEL IMMUNOTHERAPY, IN ADULTS WITH RECURRENT GBM: A HIGH PARAMETER FLOW CYTOMETRY ANALYSIS OF CD8+ T CELLS AND POTENTIAL IMPLICATIONS FOR PATIENT ENRICHMENT STRATEGIES

Treatment of glioblastoma (GBM) remains a critical challenge and unmet medical need due to limited treatment options. SL-701 is a novel immunotherapy comprised of synthetic peptides designed to elicit a target-specific anti-tumor immune response against the GBM antigens IL-13Rα2, ephrinA2, and survivin. A multicenter, 2-stage, phase 2 clinical trial (NCT02078648) that evaluated the safety and efficacy of SL-701 in 74 adults with recurrent GBM was previously reported. This report describes preliminary data to suggest a correlation of immunocompetence to clinical outcome. In stage 2 (SL-701 + bevacizumab + poly-ICLC) the overall survival at 12 months was 50%. Two of 28 patients enrolled in stage 2 achieved CR (duration of response: 7.8 and 8.8 months) and 2 achieved PR (duration of response: 7.9 and 8.8 months). In a preliminary analysis to assess CD8+ T-cell responses, long-term survivors were comprised largely of subjects with an SL-701-induced target-specific CD8+ T-cell response, indicating a potential correlation of immunocompetence to clinical outcome. By week 24, SL-701-induced target-specific CD8+ T cells expressing IFNg were detected in 8 of 27 patients (30%) who had sufficient samples, with co-expression of PD-1, TIM3, and LAG3 detected in 4 patients. To further understand the T-cell response to SL-701, deep sequencing of target-specific CD8+ T cells using whole transcriptome-based molecular cytometry and high parameter (25+ color) flow cytometry is currently underway and updated data will be reported.

RTID-08. MACHINE LEARNING TO UNCOVER SIGNATURES OF VULNERABILITY IN GLIOBLASTOMA UMBRELLA SIGNATURE TRIAL (GUST)

Glioblastoma is characterized by intra- and inter-tumoral heterogeneity. A glioblastoma umbrella signature trial (GUST) posits multiple investigational treatment arms based on corresponding biomarker signatures. A contingency of an efficient umbrella trial is a suite of orthogonal signatures to classify patients into the likely-most-beneficial arm. Assigning optimal thresholds of vulnerability signatures to classify patients as “most-likely responders” for each specific treatment arm is a crucial task. We utilized semi-supervised machine learning, Entropy-Regularized Logistic Regression, to predict vulnerability classification. By applying semi-supervised algorithms to the TCGA GBM cohort, we were able to transform the samples with the highest certainty of predicted response into a self-labeled dataset and thus augment the training data. In this case, we developed a predictive model with a larger sample size and potential better performance. Our GUST design currently includes four treatment arms for GBM patients: Arsenic Trioxide, Methoxyamine, Selinexor and Pevonedistat. Each treatment arm manifests its own signature developed by the customized machine learning pipelines based on selected gene mutation status and whole transcriptome data. In order to increase the robustness and scalability, we also developed a multi-class/label classification ensemble model that’s capable of predicting a probability of “fitness” of each novel therapeutic agent for each patient. Such a multi-class model would also enable us to rank each arm and provide sequential treatment planning. By expansion to four independent treatment arms within a single umbrella trial, a “mock” stratification of TCGA GBM patients labeled 56% of all cases into at least one “high likelihood of response” arm. Predicted vulnerability using genomic data from preclinical PDX models correctly placed 4 out of 6 models into the “responder” group. Our utilization of multiple vulnerability signatures in a GUST trial demonstrates how a precision medicine model can support an efficient clinical trial for heterogeneous diseases such as GBM.

Surgical Therapies

CTNI-08. DB102-01 ENGAGE STUDY: A BIOMARKER-GUIDED, RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED, MULTI-CENTER PHASE 3 CLINICAL TRIAL OF DB102 IN PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA (GBM)

Precision medicine is vital for treating many cancers. Lack of valid biomarkers might contribute to the failure of drug therapy for GBM. The Denovo Genomic Marker 1 (DGM1), a novel pharmacogenomic biomarker, has been discovered by a genome-wide screen of patients treated with DB102 (enzastaurin) in a trial for lymphoma. Similarly, retrospective analyses showed that DB102 significantly improved outcomes in the biomarker positive GBM patients treated with DB102, regardless of MGMT promoter methylation status. The ENGAGE Study (DB102-01, NCT03776071) is a global Phase 3 clinical trial to confirm clinical benefits in patients with newly diagnosed GBM who are DGM1 biomarker positive. This is a prospective, randomized, double-blind, placebo-controlled, multi-center study. A total of 318 patients with newly diagnosed GBM will be enrolled. After screening, patients will be randomized to receive radiation therapy (RT) and temozolomide (TMZ) plus either DB102 or a matched placebo for 6 weeks in the Concurrent Phase, followed by DB102 or placebo for approximately 5 weeks in the Single-Agent Phase and then TMZ plus DB102 or placebo in the Adjuvant Phase (up to 12 cycles). Thereafter DB102 or placebo may be continued as a single agent for up to 2 years. The primary endpoint is overall survival (OS). The secondary endpoints include progression free survival (PFS), objective response rate (ORR) and drug safety. By April 2021, the safety-run-in part was completed. The study is now open for enrollment in the US and soon in Canada and China.

CLRM-01. MACHINE LEARNING TO UNCOVER SIGNATURES OF VULNERABILITY IN GLIOBLASTOMA UMBRELLA SIGNATURE TRIAL (GUST)

Glioblastoma is characterized by intra- and inter-tumoral heterogeneity. A glioblastoma umbrella signature trial (GUST) posits multiple investigational treatment arms based on corresponding biomarker signatures. A contingency of an efficient umbrella trial is a suite of orthogonal signatures to classify patients into the likely-most-beneficial arm. Assigning optimal thresholds of vulnerability signatures to classify patients as “most-likely responders” for each specific treatment arm is a crucial task. We utilized semi-supervised machine learning, Entropy-Regularized Logistic Regression, to predict vulnerability classification. By applying semi-supervised algorithms to the TCGA GBM cohort, we were able to transform the samples with the highest certainty of predicted response into a self-labeled dataset and thus augment the training data. In this case, we developed a predictive model with a larger sample size and potential better performance. Our GUST design currently includes four treatment arms for GBM patients: Arsenic Trioxide, Methoxyamine, Selinexor and Pevonedistat. Each treatment arm manifests its own signature developed by the customized machine learning pipelines based on selected gene mutation status and whole transcriptome data. In order to increase the robustness and scalability, we also developed a multi-class/label classification ensemble model that’s capable of predicting a probability of “fitness” of each novel therapeutic agent for each patient. Such a multi-class model would also enable us to rank each arm and provide sequential treatment planning. By expansion to four independent treatment arms within a single umbrella trial, a “mock” stratification of TCGA GBM patients labeled 56% of all cases into at least one “high likelihood of response” arm. Predicted vulnerability using genomic data from preclinical PDX models correctly placed 4 out of 6 models into the “responder” group. Our utilization of multiple vulnerability signatures in a GUST trial demonstrates how a precision medicine model can support an efficient clinical trial for heterogeneous diseases such as GBM.

Abstract 180: Identifying signatures of vulnerability through machine learning in an umbrella trial for glioblastoma

Glioblastoma is characterized by intra- and inter-tumoral heterogeneity. An umbrella trial tests multiple investigational treatment arms depending on corresponding biomarker signatures. A contingency of an efficient umbrella trial is a suite of preferably orthogonal molecular biomarkers to classify patients into the likely-most-beneficial arm. Assigning thresholds of molecular signatures to classify a patient as a “most-likely responder” for one specific treatment arm is a crucial task. Gene Set Variation Analysis (GSVA) of specimens from a GBM clinical trial of methoxyamine associated differential enrichment in DNA repair pathways activities with patient response. However, the large number of DNA-repair related pathways confound confident “high” enrichment of responder, as well as obscuring to what degree each feature contributes to the likelihood of a patient's response. Here, we utilized semi-supervised machine learning, Entropy-Regularized Logistic Regression (ERLR) to predict vulnerability classification. By first training all available data using semi-supervised algorithms we transformed unclassified TCGA GBM samples with highest certainty of predicted response into a self-labeled dataset. In this case, we developed a predictive model which has a larger sample size and potential better performance. Our umbrella trial design currently includes three treatment arms for GBM patients: arsenic trioxide, methoxyamine, and pevonedistat. Each treatment arm manifests its own signature developed by the above (or similar) machine learning pipeline based on selected gene mutation status and whole transcriptome data. In order to increase the robustness and scalability (with future more treatment arms), we also developed a multi-label classification ensemble model that's capable of predicting a probability of “fitness” of each novel therapeutic agent for each patient. By expansion to three, independent treatment arms within a single umbrella trial, a “mock” stratification of TCGA GBM patients labeled 56% of all cases into at least one “high likelihood of response” arm. Predicted vulnerability using genomic data from preclinical PDX models placed 4 out of 6 models into a “high likelihood of response” regimen. Our utilization of multiple vulnerability signatures in an umbrella trial demonstrates how a precision medicine model can support an efficient clinical trial for heterogeneous diseases such as GBM.

Citation Format: Matthew Eric Lee, Nanyun Tang, Manmeet Ahluwalia, Ekokobe Fonkem, Karen Fink, Harshil Dhurv, Harshil Dhurv, Michael E. Berens, Sen Peng. Identifying signatures of vulnerability through machine learning in an umbrella trial for glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 180.

A Bayesian adaptive randomized phase II multicenter trial of bevacizumab with or without vorinostat in adults with recurrent glioblastoma

BACKGROUND

Bevacizumab has promising activity against recurrent glioblastoma (GBM). However, acquired resistance to this agent results in tumor recurrence. We hypothesized that vorinostat, a histone deacetylase (HDAC) inhibitor with anti-angiogenic effects, would prevent acquired resistance to bevacizumab.

METHODS

This multicenter phase II trial used a Bayesian adaptive design to randomize patients with recurrent GBM to bevacizumab alone or bevacizumab plus vorinostat with the primary endpoint of progression-free survival (PFS) and secondary endpoints of overall survival (OS) and clinical outcomes assessment (MD Anderson Symptom Inventory Brain Tumor module [MDASI-BT]). Eligible patients were adults (≥18 y) with histologically confirmed GBM recurrent after prior radiation therapy, with adequate organ function, KPS ≥60, and no prior bevacizumab or HDAC inhibitors.

RESULTS

Ninety patients (bevacizumab + vorinostat: 49, bevacizumab: 41) were enrolled, of whom 74 were evaluable for PFS (bevacizumab + vorinostat: 44, bevacizumab: 30). Median PFS (3.7 vs 3.9 mo, P = 0.94, hazard ratio [HR] 0.63 [95% CI: 0.38, 1.06, P = 0.08]), median OS (7.8 vs 9.3 mo, P = 0.64, HR 0.93 [95% CI: 0.5, 1.6, P = 0.79]) and clinical benefit were similar between the 2 arms. Toxicity (grade ≥3) in 85 evaluable patients included hypertension (n = 37), neurological changes (n = 2), anorexia (n = 2), infections (n = 9), wound dehiscence (n = 2), deep vein thrombosis/pulmonary embolism (n = 2), and colonic perforation (n = 1).

CONCLUSIONS

Bevacizumab combined with vorinostat did not yield improvement in PFS or OS or clinical benefit compared with bevacizumab alone or a clinical benefit in adults with recurrent GBM. This trial is the first to test a Bayesian adaptive design with adaptive randomization and Bayesian continuous monitoring in patients with primary brain tumor and demonstrates the feasibility of using complex Bayesian adaptive design in a multicenter setting.

BIOM-24. IDENTIFYING VULNERABILITY SIGNATURES THROUGH MACHINE LEARNING IN AN UMBRELLA TRIAL FOR GLIOBLASTOMA

Glioblastoma is characterized by intra- and inter-tumoral heterogeneity. An umbrella trial tests multiple treatment arms depending on corresponding biomarker signatures. A contingency of an umbrella trial is a suite of preferably orthogonal molecular biomarkers to classify patients into the likely-most-beneficial arm. Assigning thresholds of molecular signatures to classify a patient as a “most-likely responder” for one specific treatment arm is a crucial task. Gene Set Variation Analysis (GSVA) of specimens from a GBM clinical trial of methoxyamine associated differential enrichment in DNA repair pathways activities with patient response. The 44 DNA-repair related pathways confound confident “high” enrichment of responder, as well as obscuring to what degree each feature contributes to the likelihood of a patient’s response. Here, we utilized semi-supervised machine learning, Entropy-Regularized Logistic Regression (ERLR) to predict classification. By first training all available data using semi-supervised algorithms we transformed unclassified TCGA GBM samples with highest certainty of predicted response into a self-labeled dataset. In this case, we developed the predictive model which has a larger sample size and potential better performance. Our umbrella trial design currently includes three treatment arms for GBM patients: arsenic trioxide, methoxyamine, and pevonedistat. Each treatment arm manifests its own signature developed by the above (or similar) machine learning pipeline based on selected gene mutation status and whole transcriptome data. By expansion to three, independent treatment arms within a single umbrella trial, a “mock” stratification of TCGA GBM patients binned 56% of all cases into a “high likelihood of response“ arm. Predicted vulnerability using genomic data from preclinical PDX models placed 4 out of 6 models into a “high likelihood of response” regimen. Our utilization of multiple vulnerability signatures in an umbrella trial demonstrates how a precision medicine model can support an efficient clinical trial for heterogeneous diseases such as GBM.

Abstract 2007: Development of a clinical assay for predicting glioblastoma (GBM) patients most likely to respond to arsenic trioxide (ATO)

Glioblastoma (GBM) is the most frequently reported primary malignant brain tumor (29.6%). The prognosis for patients who develop GBM is bleak, with average survival after diagnosis of 12-16 months. Although conventional treatment with surgery, irradiation, and temozolomide postpones tumor progression and extends patients survival, these tumors universally recur and unrelentingly result in patient death. Personalized therapies against molecular targets that drive the growth of the bulk of primary tumors have so far been unsuccessful in clinical trials, due to lack of biomarker driven approaches. Thus, there is significant unmet need to begin biomarker driven precision medicine trials for treatment of GBM. Arsenic trioxide (ATO) is an inorganic compound that induces apoptosis via multiple pathways. Arsenic trioxide (TRISENOX®) is approved by the FDA for patients with acute promyelocytic leukemia (APL). Pre-clinical studies in brain tumors suggest that ATO is synergistic with radiation therapy (RT) and may enhance effects of radiation. In an earlier Phase II clinical trial (NCT00275067) using intravenous ATO and temozolomide in combination with radiation therapy for patients with newly diagnosed malignant gliomas, a subset of patients demonstrated notable benefit (Progression free survival (avg. = 638 days) and overall survival (avg. = 967 days)). Comparing RNAseq data from preclinical models and specimen from the Phase II clinical trial, the responder group could be confidently distinguished from the non-responder cohort leading to gene signatures of differential ATO sensitivity. Applying a Relative Expression Ordering (REO) Analysis framework, we pinpointed a probability-based roster of 28 top scoring pairs (TSP) as the classifier by which to identify patients with a higher likelihood to benefit from including ATO in combination with TMZ and radiation. This method is completely independent of platform on which data is collected and can be used for analysis of individual, newly-enrolled, n = 1 patients. We are advancing a protocol using the above gene classifier as enrollment criteria for an Adaptive clinical trial testing an oral formulation of ATO for newly diagnosed IDH1 WT Primary GBM patients; the trial will test whether patients whose tumors with ATO Classifier show 6-month PFS benefit by addition of ATO to Standard-of-Care. The trial will validate and refine the comprehensive biomarker panel that could identify most likely GBM responders to ATO and TMZ treatment in combination with radiation. Supported by a grant from the Baylor Scott & White Foundation.

Citation Format: Sen Peng, Jinghua Gu, Xuan Wang, Sanhita Rath, Jacob Cardenas, Nicholas Schork, George Snipes, Harshil Dhruv, Karen Fink, Michael Berens. Development of a clinical assay for predicting glioblastoma (GBM) patients most likely to respond to arsenic trioxide (ATO) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2007.

Abstract 857: Discovering molecular biomarkers through machine learning to assign patients to one of multiple arms for most-likely-to-benefit in an umbrella trial for glioblastoma

Glioblastoma Multiforme (GBM) is the most common primary brain tumor, characterized by intra- and inter-tumoral heterogeneity and relentless, lethal progression. Molecular data from next-generation sequencing subclassifies the disease into discrete subtypes, setting the stage for biomarker-driven clinical trials. An umbrella trial tests various treatment arms depending on various biomarker signatures that preferentially assign each new patient into a specific treatment arm. A contingency of an umbrella trial is a suite of distinct, orthogonal molecular biomarkers to classify patients into the likely-most-beneficial arm of the different separate treatment arms. Assigning thresholds to molecular signatures in order to classify a patient as a likely-responder within a single treatment arm is a crucial task. For example, in GBM patients treated with methoxyamine (covalently binds to apurinic/apyrimidinic (AP) DNA damage sites), Gene Set Variation Analysis (GSVA) identifies the differential enrichment in several DNA repair pathways of individuals. The 44 DNA-repair related pathways (or features) make it difficult to define “high” enrichment, as well as which, and to what degree, each feature contributes to the likelihood of a patient's response. Here, we utilize two semi-supervised algorithms, the Transductive Support Vector Machine (TSVM) and Entropy-Regularized Logistic Regression (ERLR). By first training these algorithms in a semi-supervised method using both patient as well as TCGA samples we can then transform the output of GSVA on unlabeled TCGA samples into a labeled data set based on those with the highest certainty of their predicted response. By employing semi-supervised algorithms to self-label the response of GBM Cases in TCGA, a predictive model can be developed which has a larger sample number, thereby reducing uncertainty.

Our umbrella trial design currently includes three treatment arms for GBM patients: arsenic trioxide, methoxyamine, and pevonedistat. Each treatment arm contains its own biomarker developed by the above machine learning pipeline based on selected gene mutation status in addition to whole transcriptome data. By conducting a “mock” stratification of GBM patients in TCGA, we identify likely patient responders in a single arm (as low as 9%) to upwards of 45% by expansion to three, independent treatment arms within a single trial. Our utilization of multiple biomarker signatures in an umbrella trial demonstrates how a precision medicine model can be effective in heterogeneous diseases such as GBM.

Citation Format: Matthew E. Lee, Sen Peng, Brett Taylor, Shay Ferdosi, Harshil Dhruv, Manmeet Ahluwalia, Karen Fink, Michael Berens. Discovering molecular biomarkers through machine learning to assign patients to one of multiple arms for most-likely-to-benefit in an umbrella trial for glioblastoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 857.

ACTR-13. FINAL RESULTS WITH CHEMORADIOTHERAPY FOR ANAPLASTIC OLIGODENDROGLIAL TUMORS FROM NRG ONCOLOGY/RTOG 9402

BACKGROUND

Adding intensive-procarbazine, lomustine, and vincristine (iPCV) to radiotherapy (RT) prolonged progression-free (PFS) and overall survival (OS) for patients with 1p19q codeleted anaplastic oligodendroglial tumors (AOTs); some benefit was also observed for IDH-mutant non-codeleted cases (Cairncross et al 2013, 2014, 2016). Now, 25 years after study activation, we updated survival, further assessed IDH as a predictive biomarker, and are exploring the benefit from vincristine.

METHODS

Eligible adults (KPS ≥ 60, adequate end-organ function) were randomized to pre-RT iPCV (4 cycles x 6 weeks each) vs. RT alone, stratified by age (< or ≥ 50), KPS (60–70 or ≥ 80), and level of anaplasia. Histology (anaplastic oligodendroglioma/oligo-astrocytoma required) and biomarkers (IDH and 1p19q, post-hoc) were determined centrally. Survival was estimated by Kaplan-Meier and Hazard Ratios (HRs) by Cox-regression.

RESULTS

Overall (n=289), median follow-up was 16.4 years vs. 11.3 years at last report. In codeleted cases, 40% randomized to iPCV remained alive vs. 53% at last report; 5, 10, and 14 year-PFS and -OS rates were 62%, 50%, 41% and 70%, 57%, 46%, respectively; and iPCV unequivocally prolonged PFS (median 9.8 vs. 2.9 years, HR 0.46, 95% CI 0.3–0.7, p< 0.001) and OS (median 13.2 vs. 7.3 years, HR 0.61, 95% CI 0.40–0.94; p=0.02). With IDH mutation but without codeletion (n=66), iPCV prolonged PFS (median 2.8 vs. 1.9 years, HR 0.58, 95% CI 0.34–0.99, p=0.046); OS was longer with a trend for significance (median 5.5 vs. 3.3 years, HR 0.6, 95% CI 0.34–1.03, p=0.06) on this underpowered exploratory post-hoc analysis.

CONCLUSION

For codeleted AOTs, long-term analyses confirmed that pre-RT iPCV produced meaningful and significant prolongations of PFS and OS. With IDH mutation but without codeletion, iPCV significantly prolonged PFS and showed a trend for prolonged OS. The value of vincristine is being assessed. Supported by NCI grants U10CA180868, U10CA180822, U24CA196067, and UG1CA189867.

Adult Primary Peripheral PNET/Ewing's Sarcoma of the Cervical and Thoracic Spine

This case report describes a patient with a rare occurrence of primary spinal intramedullary Ewing's sarcoma (ES) in the cervical and thoracic spine. The older age of disease occurrence, uncommon location in the cervical and thoracic spine, and EWSR1 gene fusion as the basis of diagnosis are unique features of this case. There is no clear protocol for treatment of primary extraskeletal ES of the spine, with controversy between evidence for pursuing surgery versus a combination of radiation and chemotherapy. Our patient was treated with temozolomide chemotherapy for recurrent metastatic disease of primary ES of the spine.

[Freiburg Cardiac Arrest Receiving Team (CART) : Interdisciplinary solution for the acute management of non-traumatic out-of-hospital cardiac arrest]

Standard procedures and guidelines provide specific instructions for basic and advanced cardiac life support. Recommendations for the admission of patients from preclinical into clinical structures after successful cardiopulmonary resuscitation (CPR) are available, but only a few are detailed. In the presence of ST-elevation myocardial infarction after return of spontaneous circulation (ROSC), coronary angiography must be performed as soon as possible. However, acute management and consecutive diagnostic procedures after hospital admission are up to the doctor on duty, who can rely on standard internal hospital procedures at best. Despite the enormous progress and new findings in intensive care and emergency medicine, intra-hospital mortality, as well as long-term survival, after CPR remains low and depends on a wide variety of influencing factors. To optimize in-hospital acute care of successfully resuscitated patients, an interdisciplinary admission team, a so-called cardiac arrest receiving team (CART), has been implemented at the University Hospital of Freiburg, Germany. The aim of the CART is to provide primary care to resuscitated patients as quickly and in as standardized a manner as possible with predefined diagnostic and therapeutic pathways by a team with special expertise in the field of CPR and post-resuscitation management. Accordingly, clear criteria for procedures and the location of primary care (e.g. emergency room vs. cardiac catheter laboratory), the composition of the CART and concrete treatment measures were defined.

A Randomized Double-Blind Placebo-Controlled Phase II Trial of Dendritic Cell Vaccine ICT-107 in Newly Diagnosed Patients with Glioblastoma

PURPOSE

To evaluate the results of the randomized, double-blind, placebo-controlled phase II clinical trial of ICT-107 in patients with newly diagnosed glioblastoma.

PATIENTS AND METHODS

We conducted a double-blinded randomized phase II trial of ICT-107 in newly diagnosed patients with glioblastoma (GBM) and tested efficacy, safety, quality of life (QoL), and immune response. HLA-A1⁺ and/or -A2⁺-resected patients with residual tumor ≤1 cm³ received radiotherapy and concurrent temozolomide. Following completion of radiotherapy, 124 patients, randomized 2:1, received ICT-107 [autologous dendritic cells (DC) pulsed with six synthetic peptide epitopes targeting GBM tumor/stem cell-associated antigens MAGE-1, HER-2, AIM-2, TRP-2, gp100, and IL13Rα2] or matching control (unpulsed DC). Patients received induction ICT-107 or control weekly × 4 followed by 12 months of adjuvant temozolomide. Maintenance vaccinations occurred at 1, 3, and 6 months and every 6 months thereafter.

RESULTS

ICT-107 was well tolerated, with no difference in adverse events between the treatment and control groups. The primary endpoint, median overall survival (OS), favored ICT-107 by 2.0 months in the intent-to-treat (ITT) population but was not statistically significant. Progression-free survival (PFS) in the ITT population was significantly increased in the ICT-107 cohort by 2.2 months (P = 0.011). The frequency of HLA-A2 primary tumor antigen expression was higher than that for HLA-A1 patients, and HLA-A2 patients had higher immune response (via Elispot). HLA-A2 patients achieved a meaningful therapeutic benefit with ICT-107, in both the MGMT methylated and unmethylated prespecified subgroups, whereas only HLA-A1 methylated patients had an OS benefit.

CONCLUSIONS

PFS was significantly improved in ICT-107-treated patients with maintenance of QoL. Patients in the HLA-A2 subgroup showed increased ICT-107 activity clinically and immunologically.

[Postcardiac arrest treatment guide]

BACKGROUND

Treatment after cardiac arrest has become more complex and interdisciplinary over the last few years. Thus, the clinically active intensive and emergency care physician not only has to carry out the immediate care and acute diagnostics, but also has to prognosticate the neurological outcome.

AIM

The different, most important steps are presented by leading experts in the area, taking into account the interdisciplinarity and the currently valid guidelines.

MATERIALS AND METHODS

Attention was paid to a concise, practice-oriented presentation.

RESULTS AND DISCUSSION

The practical guide contains all important steps from the acute care to the neurological prognosis generation that are relevant for the clinically active intensive care physician.

A multicenter phase II study of temozolomide plus disulfiram and copper for recurrent temozolomide-resistant glioblastoma

PURPOSE

Preclinical studies have suggested promising activity for the combination of disulfiram and copper (DSF/Cu) against glioblastoma (GBM) including re-sensitization to temozolomide (TMZ). A previous phase I study demonstrated the safety of combining DSF/Cu with adjuvant TMZ for newly diagnosed GBM. This phase II study aimed to estimate the potential effectiveness of DSF/Cu to re-sensitize recurrent GBM to TMZ.

METHODS

This open-label, single-arm phase II study treated recurrent TMZ-resistant GBM patients with standard monthly TMZ plus concurrent daily DSF 80 mg PO TID and Cu 1.5 mg PO TID. Eligible patients must have progressed after standard chemoradiotherapy and within 3 months of the last dose of TMZ. Known isocitrate dehydrogenase (IDH) mutant or secondary GBMs were excluded. The primary endpoint was objective response rate (ORR), and the secondary endpoints included progression-free survival (PFS), overall survival (OS), clinical benefit (response or stable disease for at least 6 months), and safety.

RESULTS

From March 2017 to January 2018, 23 recurrent TMZ-resistant GBM patients were enrolled across seven centers, and 21 patients were evaluable for response. The median duration of DSF/Cu was 1.6 cycles (range: 0.1-12.0). The ORR was 0%, but 14% had clinical benefit. Median PFS was 1.7 months, and median OS was 7.1 months. Only one patient (4%) had dose-limiting toxicity (grade three elevated alanine transaminase).

CONCLUSIONS

Addition of DSF/Cu to TMZ for TMZ-resistant IDH-wild type GBM appears well tolerated but has limited activity for unselected population.

Stripping off hydrogens in imidazole triggered by the attachment of a single electron

Imidazole [C₃H₄N₂] is ubiquitous in nature as an important biological building block of amino acids, purine nucleobases or antibiotics. In the present study, dissociative electron attachment to imidazole shows low energy shape resonances at 1.52 and 2.29 eV leading to the most abundant dehydrogenated anion [imidazole - H]^- through dehydrogenation at the N1 position. All the other anions formed exhibit core excited resonances observed dominantly at similar electron energies of ∼7 and 11 eV, suggesting an initial formation through two temporary negative ion states. Among these anions, multiple dehydrogenation reactions are observed resulting in the loss of 2 up to 4 hydrogens, thus, leading to a complete dehydrogenation of the imidazole molecule, an interesting prototype of complex unimolecular decay induced by the attachment of a single electron. Additionally, the quantum chemical calculations reveal that these multiple dehydrogenation reactions are responsible for the remarkable one electron-induced gas-phase chemistry leading to the opening of the ring. The formation of the observed anions is likely driven by the high positive electron affinity of cyanocarbon molecules supported by quantum chemical calculations. The formation of H^- showed additional resonance at about 5 eV and dipolar dissociation above ∼14 eV.

Effect of Tumor-Treating Fields Plus Maintenance Temozolomide vs Maintenance Temozolomide Alone on Survival in Patients With Glioblastoma: A Randomized Clinical Trial

IMPORTANCE

Tumor-treating fields (TTFields) is an antimitotic treatment modality that interferes with glioblastoma cell division and organelle assembly by delivering low-intensity alternating electric fields to the tumor.

OBJECTIVE

To investigate whether TTFields improves progression-free and overall survival of patients with glioblastoma, a fatal disease that commonly recurs at the initial tumor site or in the central nervous system.

DESIGN, SETTING, AND PARTICIPANTS

In this randomized, open-label trial, 695 patients with glioblastoma whose tumor was resected or biopsied and had completed concomitant radiochemotherapy (median time from diagnosis to randomization, 3.8 months) were enrolled at 83 centers (July 2009-2014) and followed up through December 2016. A preliminary report from this trial was published in 2015; this report describes the final analysis.

INTERVENTIONS

Patients were randomized 2:1 to TTFields plus maintenance temozolomide chemotherapy (n = 466) or temozolomide alone (n = 229). The TTFields, consisting of low-intensity, 200 kHz frequency, alternating electric fields, was delivered (≥ 18 hours/d) via 4 transducer arrays on the shaved scalp and connected to a portable device. Temozolomide was administered to both groups (150-200 mg/m2) for 5 days per 28-day cycle (6-12 cycles).

MAIN OUTCOMES AND MEASURES

Progression-free survival (tested at α = .046). The secondary end point was overall survival (tested hierarchically at α = .048). Analyses were performed for the intent-to-treat population. Adverse events were compared by group.

RESULTS

Of the 695 randomized patients (median age, 56 years; IQR, 48-63; 473 men [68%]), 637 (92%) completed the trial. Median progression-free survival from randomization was 6.7 months in the TTFields-temozolomide group and 4.0 months in the temozolomide-alone group (HR, 0.63; 95% CI, 0.52-0.76; P < .001). Median overall survival was 20.9 months in the TTFields-temozolomide group vs 16.0 months in the temozolomide-alone group (HR, 0.63; 95% CI, 0.53-0.76; P < .001). Systemic adverse event frequency was 48% in the TTFields-temozolomide group and 44% in the temozolomide-alone group. Mild to moderate skin toxicity underneath the transducer arrays occurred in 52% of patients who received TTFields-temozolomide vs no patients who received temozolomide alone.

CONCLUSIONS AND RELEVANCE

In the final analysis of this randomized clinical trial of patients with glioblastoma who had received standard radiochemotherapy, the addition of TTFields to maintenance temozolomide chemotherapy vs maintenance temozolomide alone, resulted in statistically significant improvement in progression-free survival and overall survival. These results are consistent with the previous interim analysis.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00916409.

Multi-platform molecular profiling of a large cohort of glioblastomas reveals potential therapeutic strategies

Glioblastomas (GBM) are the most aggressive and prevalent form of gliomas with abysmal prognosis and limited treatment options. We analyzed clinically relevant molecular aberrations suggestive of response to therapies in 1035 GBM tumors. Our analysis revealed mutations in 39 genes of 48 tested. IHC revealed expression of PD-L1 in 19% and PD-1 in 46%. MGMT-methylation was seen in 43%, EGFRvIII in 19% and 1p19q co-deletion in 2%. TP53 mutation was associated with concurrent mutations, while IDH1 mutation was associated with MGMT-methylation and TP53 mutation and was mutually exclusive of EGFRvIII mutation. Distinct biomarker profiles were seen in GBM compared with WHO grade III astrocytoma, suggesting different biology and potentially different treatment approaches. Analysis of 17 metachronous paired tumors showed frequent biomarker changes, including MGMT-methylation and EGFR aberrations, indicating the need for a re-biopsy for tumor profiling to direct subsequent therapy. MGMT-methylation, PR and TOPO1 appeared as significant prognostic markers in sub-cohorts of GBM defined by age. The current study represents the largest biomarker study on clinical GBM tumors using multiple technologies to detect gene mutation, amplification, protein expression and promoter methylation. These data will inform planning for future personalized biomarker-based clinical trials and identifying effective treatments based on tumor biomarkers.

The immunogenetics of narcolepsy associated with A(H1N1)pdm09 vaccination (Pandemrix) supports a potent gene-environment interaction

The influenza A(H1N1)pdm09 vaccination campaign from 2009 to 2010 was associated with a sudden increase in the incidence of narcolepsy in several countries. Narcolepsy with cataplexy is strongly associated with the human leukocyte antigen (HLA) class II DQB1*06:02 allele, and protective associations with the DQB1*06:03 allele have been reported. Several non-HLA gene loci are also associated, such as common variants of the T-cell receptor-α (TRA), the purinergic receptor P2RY11, cathepsin H (CTSH) and TNFSF4/OX40L/CD252. In this retrospective multicenter study, we investigated if these predisposing gene loci were also involved in vaccination-associated narcolepsy. We compared HLA- along with single-nucleotide polymorphism genotypes for non-HLA regions between 42 Pandemrix-vaccinated narcolepsy cases and 1990 population-based controls. The class II gene loci associations supported previous findings. Nominal association (P-value<0.05) with TRA as well as suggestive (P-value<0.1) associations with P2RY11 and CTSH were found. These associations suggest a very strong gene-environment interaction, in which the influenza A(H1N1)pdm09 strain or Pandemrix vaccine can act as potent environmental triggers.

Interaction of Pubertal Development and Metabolic Control in Adolescents with Type 1 Diabetes Mellitus

BACKGROUND

In T1DM, delayed pubertal development and reduced final height are associated with inadequate metabolic control.

OBJECTIVE

To assess whether T1DM affects pubertal growth spurt and whether metabolic control during puberty is gender-related.

METHODS

Using a large multicentre database, longitudinal data from 1294 patients were analysed. Inclusion criteria: complete records of height and HbA1c from the age of seven to 16 years. Exclusion criteria: other significant chronic diseases and medications, T1DM duration less than three months, and initial BMI < 3rd or >97th percentile.

RESULTS

Growth velocity (GV) was impaired with a significant reduction of peak GV by 1.2 cm in boys. HbA1c increase during male puberty was lower except for a period of 1.5 years. The highest HbA1c increase in boys coincided with maximum growth spurt. In girls, the highest HbA1c increase was observed during late puberty. Even though there is impaired GV, both sexes reach a height at 16 years of age which corresponds to the background population height.

CONCLUSION

Worsening of metabolic control is sex-discordant and associated with gender-specific alterations of GV. However, the vast majority of boys and girls with T1DM seems to reach normal height at the age of 16 years.

The effect of sazetidine-A and other nicotinic ligands on nicotine controlled goal-tracking in female and male rats

Nicotine is the primary addictive component of tobacco products and its complex stimulus effects are readily discriminated by human and non-human animals. Previous research with rodents directly investigating the nature of the nicotine stimulus has been limited to males. The current study began to address this significant gap in the literature by training female and male rats to discriminate 0.4 mg/kg nicotine from saline in the discriminated goal-tracking task. In this task, access to sucrose was intermittently available on nicotine session. On interspersed saline session, sucrose was not available. Both sexes acquired the discrimination as evidenced by increased head entries into sucrose receptacle (goal-tracking) evoked by nicotine; the nicotine generalization curves were also similar between females and males. The pharmacological profile of the nicotine stimulus was assessed using substitution and targeted combination tests with the following ligands: sazetidine-A, PHA-543613, PNU-120596, bupropion, nornicotine, and cytisine. For females and males, nornicotine fully substituted for the nicotine stimulus, whereas sazetidine-A, bupropion, and cytisine all evoked partial substitution. Female and male rats responded in a similar manner to interaction tests where a combination of 1 mg/kg of sazetidine-A plus nicotine or nornicotine shifted the nicotine dose-effect curve to the left. The combination of sazetidine-A plus bupropion or cytisine failed to do so. These findings begin to fill a significant gap the in scientific literature by studying the nature of the nicotine stimulus and response to therapeutically interesting combinations using a model that includes both sexes.

Increased β-haemolytic group A streptococcal M6 serotype and streptodornase B-specific cellular immune responses in Swedish narcolepsy cases

BACKGROUND

Type 1 narcolepsy is a neurological disorder characterized by excessive daytime sleepiness and cataplexy associated with the HLA allele DQB1*06:02. Genetic predisposition along with external triggering factors may drive autoimmune responses, ultimately leading to the selective loss of hypocretin-positive neurons.

OBJECTIVE

The aim of this study was to investigate potential aetiological factors in Swedish cases of postvaccination (Pandemrix) narcolepsy defined by interferon-gamma (IFNγ) production from immune cells in response to molecularly defined targets.

METHODS

Cellular reactivity defined by IFNγ production was examined in blood from 38 (HLA-DQB1*06:02(+) ) Pandemrix-vaccinated narcolepsy cases and 76 (23 HLA-DQB1*06:02(+) and 53 HLA-DQB1*06:02(-) ) control subjects, matched for age, sex and exposure, using a variety of different antigens: β-haemolytic group A streptococcal (GAS) antigens (M5, M6 and streptodornase B), influenza (the pandemic A/H1N1/California/7/09 NYMC X-179A and A/H1N1/California/7/09 NYMC X-181 vaccine antigens, previous Flu-A and -B vaccine targets, A/H1N1/Brisbane/59/2007, A/H1N1/Solomon Islands/3/2006, A/H3N2/Uruguay/716/2007, A/H3N2/Wisconsin/67/2005, A/H5N1/Vietnam/1203/2004 and B/Malaysia/2506/2004), noninfluenza viral targets (CMVpp65, EBNA-1 and EBNA-3) and auto-antigens (hypocretin peptide, Tribbles homolog 2 peptide cocktail and extract from rat hypothalamus tissue).

RESULTS

IFN-γ production was significantly increased in whole blood from narcolepsy cases in response to streptococcus serotype M6 (P = 0.0065) and streptodornase B protein (P = 0.0050). T-cell recognition of M6 and streptodornase B was confirmed at the single-cell level by intracellular cytokine (IL-2, IFNγ, tumour necrosis factor-alpha and IL-17) production after stimulation with synthetic M6 or streptodornase B peptides. Significantly, higher (P = 0.02) titres of serum antistreptolysin O were observed in narcolepsy cases, compared to vaccinated controls.

CONCLUSION

β-haemolytic GAS may be involved in triggering autoimmune responses in patients who developed narcolepsy symptoms after vaccination with Pandemrix in Sweden, characterized by a Streptococcus pyogenes M-type-specific IFN-γ cellular immune response.

Influence of gelsolin deficiency on excitation contraction coupling in adult murine cardiomyocytes

Ion channels involved in cardiac excitation-contraction coupling are linked to the cytoskeleton. Therefore changes in the cytoskeletal actin filaments may influence cardiac membrane currents and electro-mechanical coupling. Depolymerization of actin filaments by gelsolin (gsn) is involved in the organisation of the cytoskeleton by leading to a lower polymerization state. Gsn is activated by Ca(2+) and inhibited by phosphoinositol-bisphosphate (PIP2). Furthermore, gsn has been linked to pathological conditions with reduced contractility like heart failure, amyloidosis and apoptosis. Thus, we hypothesize, that gsn deficiency may change electromechanical properties of freshly isolated ventricular cardiomyocytes. We recorded L-type Ca(2+) current (ICa,L) in whole-cell patch clamp mode in freshly isolated ventricular cardiomyocytes from gsn deficient ((-/-)) and control (gsn(+/+)) mice. Sarcomere shortening was monitored in field-stimulated myocytes from 0.5 Hz to 10 Hz by video microscopy. Shortening-frequency relation, post-rest potentiation and β-adrenergic stimulation were investigated. ICa,L was increased in gsn(-/-) vs. gsn(+/+) myocytes. Sarcomere shortening amplitude and velocity were enhanced in gsn(-/-) vs. gsn(+/+) at all frequencies. Shortening-frequency relationship showed a biphasic pattern with decay in shortening amplitude between 0.5 and 2 Hz and an increase at higher frequencies in both genotypes. Post-rest characteristics revealed a frequency-dependent decay of post-rest potentiation in gsn(+/+) while it remained stable in gsn(-/-). In gsn(-/-) a reduced response to β-adrenergic stimulation was observed. Resting sarcomere length was shorter in gsn(-/-) but neither increasing frequency nor β-adrenergic stimulation induced further decay in any of the genotypes. In summary, gsn deficiency had a profound effect on excitiation-contraction properties and improved systolic function while not affecting diastolic function in unloaded isolated cardiomyocytes. Therefore, gsn mediated effects on contractility may play a role in patients with heart failure and cancer, where gsn levels are known to be elevated.

High expression of the stem cell marker nestin is an adverse prognostic factor in WHO grade II-III astrocytomas and oligoastrocytomas

Infiltrating astrocytomas and oligoastrocytomas of low to anaplastic grade (WHO grades II and III), in spite of being associated with a wide range of clinical outcomes, can be difficult to subclassify and grade by the current histopathologic criteria. Unlike oligodendrogliomas and anaplastic oligodendrogliomas that can be identified by the 1p/19q codeletion and the more malignant glioblastomas (WHO grade IV astrocytomas) that can be diagnosed solely based on objective features on routine hematoxylin and eosin sections, no such objective criteria exist for the subclassification of grade II-III astrocytomas and oligoastrocytomas (A+OA II-III). In this study, we evaluated the prognostic and predictive value of the stem cell marker nestin in adult A+OA II-III (n = 50) using immunohistochemistry and computer-assisted analysis on tissue microarrays. In addition, the correlation between nestin mRNA level and total survival was analyzed in the NCI Rembrandt database. The results showed that high nestin expression is a strong adverse prognostic factor for total survival (p = 0.0004). The strength of the correlation was comparable to but independent of the isocitrate dehydrogenase 1/2 (IDH 1/2) mutation status. Histopathological grading and subclassification did not correlate significantly with outcome, although the interpretation of this finding is limited by the fact that grade III tumors were treated more aggressively than grade II tumors. These results suggest that nestin level and IDH 1/2 mutation status are strong prognostic features in A+OA II-III and possibly more helpful for treatment planning than routine histopathological variables such as oligodendroglial component (astrocytoma vs. oligoastrocytoma) and WHO grade (grade II vs. III).

Iptakalim attenuates self-administration and acquired goal-tracking behavior controlled by nicotine

Iptakalim is an ATP-sensitive potassium channel opener, as well as an α4β2-containing nicotinic acetylcholine receptor (nAChR) antagonist. Pretreatment with iptakalim diminishes nicotine-induced dopamine (DA) and glutamate release in the nucleus accumbens. This neuropharmacological profile suggests that iptakalim may be useful for treatment of nicotine dependence. Thus, we examined the effects of iptakalim in two preclinical models. First, the impact of iptakalim on the interoceptive stimulus effect of nicotine was evaluated by training rats in a discriminated goal-tracking task that included intermixed nicotine (0.4 mg/kg, SC) and saline sessions. Sucrose was intermittently presented in a response-independent manner only on nicotine sessions. On intervening test days, rats were pretreated with iptakalim (10, 30, 60 mg/kg, IP). Results revealed that iptakalim attenuated nicotine-evoked responding controlled by the nicotine stimulus in a dose-dependent manner. In a separate study, the impact of iptakalim on the reinforcing effects of nicotine was investigated by training rats to lever-press to self-administer nicotine (0.01 mg/kg/infusion) [Dosage error corrected]. Results revealed that pretreatment with iptakalim (1, 3, 6 mg/kg, IV) decreased nicotine intake (i.e., less active lever responding). Neither behavioral effect was due to a non-specific motor effect of iptakalim, nor to an ability of iptakalim to inhibit DA transporter (DAT) or serotonin transporter (SERT) function. Together, these finding support the notion that iptakalim may be an effective pharmacotherapy for increasing smoking cessation and a better understanding of its action could contribute to medication development.

A volumetric study of CyberKnife hypofractionated stereotactic radiotherapy as salvage for progressive malignant brain tumors: initial experience

OBJECTIVE

Radiosurgery is frequently offered to patients with progressive malignant brain tumors if radiation therapy or chemotherapy fails to provide local control. The use of single-shot regimens, however, is limited by the risk of complications when the tumor is large, surrounded by edema or has been pre-treated with radiation. Hypofractionation may confer safety but has not been tested for these difficult tumors. We report the results of hypofractionation as an alternative option in a small cohort of progressive malignant brain tumors.

METHODS

Hypofractionated CyberKnife radiotherapy was chosen for 18 progressive malignant brain tumors (six high-grade gliomas and 12 metastatic lesions) in 15 patients because of size, previous treatment with radiation or surrounding edema. The mean dose was 21 +/- 4 Gy and the number of fractions was 5 +/- 0.6. The volume of each tumor at treatment was compared with the volume at follow-up.

RESULTS

Thirteen of the 18 tumors (72%) showed a volume decrease. The average volume change was a decrease of 16 +/- 58% (median: 20%) with a follow-up of 180 +/- 121 days (median: 172 days). Toxicity occurred in only one patient, with symptoms improving on steroids.

DISCUSSION

Progression of malignant brain tumors not ideal for single-shot radiosurgery can be arrested or reversed, at least for short periods, with minimal toxicity using hypofractionated radiotherapy. Longer studies will be needed to assess durability of this response in these difficult tumors.