Autologous cell immunotherapy (IGV-001) with IGF-1R antisense oligonucleotide in newly diagnosed glioblastoma patients

Standard-of-care first-line therapy for patients with newly diagnosed glioblastoma (ndGBM) is maximal safe surgical resection, then concurrent radiotherapy and temozolomide, followed by maintenance temozolomide. IGV-001, the first product of the Goldspire™ platform, is a first-in-class autologous immunotherapeutic product that combines personalized whole tumor-derived cells with an antisense oligonucleotide (IMV-001) in implantable biodiffusion chambers, with the intent to induce a tumor-specific immune response in patients with ndGBM. Here, we describe the design and rationale of a randomized, double-blind, phase IIb trial evaluating IGV-001 compared with placebo, both followed by standard-of-care treatment in patients with ndGBM. The primary end point is progression-free survival, and key secondary end points include overall survival and safety.

Body Fluids Modulate Propagation of Tumor Treating Fields

Tumor treating fields (TTFields) are nonionizing alternating electric fields that have anticancer properties. After the initial approval for use in patients with recurrent glioblastoma in 2011 and newly diagnosed glioblastomas in 2015, they are now being tested in those with advanced lung cancer, ovarian carcinoma, and pancreatic cancer. Unlike ionizing radiation therapy, TTFields have nonlinear propagation characteristics; therefore, it is difficult for clinicians to recognize intuitively the location where these fields have the most impact. However, finite element analysis offers a means of delineating TTFields in the human body. Our analyses in the brain, pelvis, and thorax revealed that cerebrospinal fluid, edema, urine, ascites, pleural fluid, and necrotic core within a tumor greatly influence their distribution within these body cavities. Our observations thus provided a unified framework on the role of these compartmentalized fluids in influencing the propagation of TTFields.

Tumor-treating fields dosimetry in glioblastoma: Insights into treatment planning, optimization, and dose-response relationships

Tumor-treating fields (TTFields) are currently a Category 1A treatment recommendation by the US National Comprehensive Cancer Center for patients with newly diagnosed glioblastoma. Although the mechanism of action of TTFields has been partly elucidated, tangible and standardized metrics are lacking to assess antitumor dose and effects of the treatment. This paper outlines and evaluates the current standards and methodologies in the estimation of the TTFields distribution and dose measurement in the brain and highlights the most important principles governing TTFields dosimetry. The focus is on clinical utility to facilitate a practical understanding of these principles and how they can be used to guide treatment. The current evidence for a correlation between TTFields dose, tumor growth, and clinical outcome will be presented and discussed. Furthermore, we will provide perspectives and updated insights into the planning and optimization of TTFields therapy for glioblastoma by reviewing how the dose and thermal effects of TTFields are affected by factors such as tumor location and morphology, peritumoral edema, electrode array position, treatment duration (compliance), array "edge effect," electrical duty cycle, and skull-remodeling surgery. Finally, perspectives are provided on how to optimize the efficacy of future TTFields therapy.

Lewy body disease as a potential negative outcome modifier of glioblastoma treatment: a case report

BACKGROUND

Elderly patients with glioblastoma are particularly susceptible to the adverse effects of ionizing radiation to the brain. This population also has an increasing prevalence of dementia in the successive seventh, eighth and nineth decade of life, and dementia with Lewy bodies is characterized by pathologic α-synucleins, proteins that take part in neuronal DNA damage repair.

CASE PRESENTATION

We report a 77-year-old man, with a history of coronary artery disease and mild cognitive impairment, who experienced subacute behavioral changes over 3 months with wording-finding difficulty, memory loss, confusion, perseveration, and irritable mood. Neuroimaging studies disclosed a 2.5 × 2.4 × 2.7 cm cystic enhancing mass with central necrosis in the left temporal lobe of the brain. Gross total resection of the tumor revealed IDH-1 wild-type glioblastoma. After treatment with radiation and temozolomide chemotherapy, his cognitive status deteriorated rapidly, and he died from unexpected sudden death 2 months after radiation. Autopsy of his brain revealed (i) tumor cells with atypical nuclei and small lymphocytes, (ii) neuronal cytoplasmic inclusions and Lewy bodies that were positive for α-synuclein in the midbrain, pons, amygdala, putamen and globus pallidus, and (iii) no amyloid plaques and only rare neurofibrillary tangles near the hippocampi.

CONCLUSIONS

This patient most likely had pre-clinical limbic subtype of dementia with Lewy bodies prior to his diagnosis of glioblastoma. The radiation and temozolomide that was used to treat his tumor may have accelerated neuronal damage due to induction of DNA breakage when his brain was already compromised by pathologic α-synucleins. α-Synucleinopathy could be a negative outcome modifier in glioblastoma patients.

Phase IIa Study of SurVaxM Plus Adjuvant Temozolomide for Newly Diagnosed Glioblastoma

PURPOSE

Despite intensive treatment with surgery, radiation therapy, temozolomide (TMZ) chemotherapy, and tumor-treating fields, mortality of newly diagnosed glioblastoma (nGBM) remains very high. SurVaxM is a peptide vaccine conjugate that has been shown to activate the immune system against its target molecule survivin, which is highly expressed by glioblastoma cells. We conducted a phase IIa, open-label, multicenter trial evaluating the safety, immunologic effects, and survival of patients with nGBM receiving SurVaxM plus adjuvant TMZ following surgery and chemoradiation (ClinicalTrials.gov identifier: NCT02455557).

METHODS

Sixty-four patients with resected nGBM were enrolled including 38 men and 26 women, in the age range of 20-82 years. Following craniotomy and fractionated radiation therapy with concurrent TMZ, patients received four doses of SurVaxM (500 μg once every 2 weeks) in Montanide ISA-51 plus sargramostim (granulocyte macrophage colony-stimulating factor) subcutaneously. Patients subsequently received adjuvant TMZ and maintenance SurVaxM concurrently until progression. Progression-free survival (PFS) and overall survival (OS) were reported. Immunologic responses to SurVaxM were assessed.

RESULTS

SurVaxM plus TMZ was well tolerated with no serious adverse events attributable to SurVaxM. Of the 63 patients who were evaluable for outcome, 60 (95.2%) remained progression-free 6 months after diagnosis (prespecified primary end point). Median PFS was 11.4 months and median OS was 25.9 months measured from first dose of SurVaxM. SurVaxM produced survivin-specific CD8+ T cells and antibody/immunoglobulin G titers. Apparent clinical benefit of SurVaxM was observed in both methylated and unmethylated patients.

CONCLUSION

SurVaxM appeared to be safe and well tolerated. The combination represents a promising therapy for nGBM. For patients with nGBM treated in this manner, PFS may be an acceptable surrogate for OS. A large randomized clinical trial of SurVaxM for nGBM is in progress.

Methylphenidate Reversal of Executive Dysfunction in a Patient with Bi-Frontal Lobe Glioblastoma

An elderly man with advanced glioblastoma developed neuro-cognitive deficits that were reversed by methylphenidate. After tumor resection from the right frontal lobe, he received cranial irradiation, temozolomide and Tumor Treating Fields (TTFields). MRI afterwards showed enhancements near the resection cavity and the contralateral frontal lobe. The patient experienced mild executive dysfunction that was not limiting his activities. Adjuvant temozolomide was started along with TTFields. After 2 cycles, his brain MRI showed stable disease, but he exhibited significant executive dysfunction. Methylphenidate improved his neuro-cognitive slowing in cycles 3 and 4. His disease eventually progressed during the 5th cycle, and he experienced a marked decline in activities. Repeat head MRI revealed tumor progression and cerebral edema. Treatments were discontinued while dexamethasone improved his neurological functions and bevacizumab biosimilar was later added. This case demonstrates the activity of methylphenidate for managing executive dysfunction in patients with glioblastoma while minimizing the use of dexamethasone.

Dimorphic glioblastoma with glial and epithelioid phenotypes: Clonal evolution and immune selection

Purpose

Epithelioid glioblastoma is an unusual histologic variant of malignant glioma. The present study investigates both the genomic and transcriptomic determinants that may promote the development of this tumor.

Methods

Whole-exome sequencing (WES) and whole-transcriptome sequencing (WTS) were performed on an epithelioid glioblastoma, along with a specific bioinformatic pipeline to generate electronic karyotyping and investigate the tumor immune microenvironment. Microdissected sections containing typical glioblastoma features and epithelioid morphology were analyzed separately using the same methodologies.

Results

An epithelioid glioblastoma, with immunopositivity for GFAP, Olig-2, and ATRX but negative for IDH-1 and p53, was identified. The tumor cell content from microdissection was estimated to be 85-90% for both histologic tumor components. WES revealed that both glioma and epithelioid sections contained identical point mutations in PTEN, RB1, TERT promoter, and TP53. Electronic karyotype analysis also revealed similar chromosomal copy number alterations, but the epithelioid component showed additional abnormalities that were not found in the glioblastoma component. The tumor immune microenvironments were strikingly different and WTS revealed high levels of transcripts from myeloid cells as well as M1 and M2 macrophages in the glioma section, while transcripts from CD4+ lymphocytes and NK cells predominated in the epithelioid section.

Conclusion

Epithelioid glioblastoma may be genomically more unstable and oncogenically more advanced, harboring an increased number of mutations and karyotype abnormalities, compared to typical glioblastomas. The tumor immune microenvironment is also different.

Choroid plexus-CSF-targeted antioxidant therapy protects the brain from toxicity of cancer chemotherapy

For many cancer patients, chemotherapy produces untreatable life-long neurologic effects termed chemotherapy-related cognitive impairment (CRCI). We discovered that the chemotherapy methotrexate (MTX) adversely affects oxidative metabolism of non-cancerous choroid plexus (ChP) cells and the cerebrospinal fluid (CSF). We used a ChP-targeted adeno-associated viral (AAV) vector approach in mice to augment CSF levels of the secreted antioxidant SOD3. AAV-SOD3 gene therapy increased oxidative defense capacity of the CSF and prevented MTX-induced lipid peroxidation in the hippocampus. Furthermore, this gene therapy prevented anxiety and deficits in short-term learning and memory caused by MTX. MTX-induced oxidative damage to cultured human cortical neurons and analyses of CSF samples from MTX-treated lymphoma patients demonstrated that MTX diminishes antioxidant capacity of patient CSF. Collectively, our findings motivate the advancement of ChP- and CSF-targeted anti-oxidative prophylactic measures to relieve CRCI.

Guidelines for Burr Hole Surgery in Combination With Tumor Treating Fields for Glioblastoma: A Computational Study on Dose Optimization and Array Layout Planning

Tumor treating fields (TTFields) is an anti-cancer technology increasingly used for the treatment of glioblastoma. Recently, cranial burr holes have been used experimentally to enhance the intensity (dose) of TTFields in the underlying tumor region. In the present study, we used computational finite element methods to systematically characterize the impact of the burr hole position and the TTFields transducer array layout on the TTFields distribution calculated in a realistic human head model. We investigated a multitude of burr hole positions and layouts to illustrate the basic principles of optimal treatment planning. The goal of the paper was to provide simple rules of thumb for physicians to use when planning the TTFields in combination with skull remodeling surgery. Our study suggests a number of key findings, namely that (1) burr holes should be placed directly above the region of interest, (2) field enhancement occurs mainly underneath the holes, (3) the ipsilateral array should directly overlap the holes and the contralateral array should be placed directly opposite, (4) arrays in a pair should be placed at far distance and not close to each other to avoid current shunting, and finally (5) rotation arrays around their central normal axis can be done without diminishing the enhancing effect of the burr holes. Minor deviations and adjustments (<3 cm) of arrays reduces the enhancement to some extent although the procedure is still effective in these settings. In conclusion, our study provides simple guiding principles for implementation of dose-enhanced TTFields in combination with burr-holes. Future studies are required to validate our findings in additional models at the patient specific level.

A pancancer analysis of impact of MDM2/MDM4 on immune checkpoint blockade (ICB)

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Background: MDM2/MDM4 are implicated in hyperprogression after immune checkpoint blockade (ICB). Our preclinical studies showed reduced T-cell killing of MDM2-amplified tumor cells that was overcome by an MDM2 antagonist or gene knockdown, and we observed additional tumor killing by T-cells with MDM2 inhibition plus anti-PD1. We hypothesized that MDM2/4 gene amplification/overexpression correlates with resistance to ICB and investigated the association of MDM2/4 alterations to overall survival (OS) following ICB across multiple solid tumors. Methods: Solid tumors tested at Caris Life Sciences (Phoenix, AZ) with NextGen Sequencing on DNA (NGS) were analyzed. MDM2/4 amplification (amp) was tested by NGS and determined as either amp4 (cutoff of >=4.0 copies) or amp6 (>=6.0) or amp8 (>=8.0). Real-world OS was obtained from insurance claims data and calculated from treatment start or tissue collection to last contact. Kaplan-Meier estimates were calculated for molecularly defined groups. X2/Fisher-Exact were used and significance determined as P-value adjusted for multiple comparisons (q<0.05). Results: In a large cohort of TP53-wild type solid tumors, 2785 had MDM2 amp4 (262 were ICB-treated), 2108 had MDM2 amp6 (ICB: 192), 1721 had MDM2 amp8 (ICB: 149); 1040 tumors had MDM4 amp4 (ICB: 59), 293 had MDM4 amp6 (ICB: 8) and 217 had amp8 (ICB: 4). NSCLC, GBM, breast, bladder cancer and liposarcoma had the highest MDM2 amp and breast cancer, GBM, uterine, NSCLC and ovarian cancers had the highest MDM4 amp. When all tumors were considered, MDM2 amp4, 6 and 8 significantly associated with shortened OS (amp4: HR 1.31; amp6: HR 1.31; amp8: 1.29, all p<0.0001); similar results were seen with MDM4 (amp4: HR 1.14, p=0.004; amp6: HR 1.51, p<0.00001 and amp8: HR 1.6, p<0.00001). Of note, MDM4 amp4 but not MDM2 amp4 was associated with significantly worse post-ICB survival (HR: 1.55, p=0.009).When comparing molecular differences between MDM2 amp4 and MDM4 amp4, significantly higher PDL1 expression was associated with MDM2 amp (Ab clone 28.8: 58% vs. 28%; clone 22c3: 48% vs.25%, q<0.05); while higher mutation rates of ARID1A, PIK3CA, PTEN, KRAS and CTNNB1 were associated with MDM4 amp (all q<0.05). When investigating NSCLC, MDM4 amp4 was associated with decreased post-ICB survival in NSCLC (HR: 2.59, p=0.001) but not MDM2; when comparing the molecular alterations, MDM2 amp was associated with significantly higher PDL1 (22c3) (54% vs. 27%), EGFR mutation (36% vs. 14%) but less prevalent KRAS (15% vs. 50%), STK11 (11% vs. 41%), KEAP1 (2.5% vs. 27%) and BRAF (2% vs. 16%) mutations. The association with poor prognosis of MDM2 amp4/6 (HR: 1.2 and 1.3, p<0.05) and MDM4 amp4/6 (HR: 1.3 and 1.6, p<0.05) was seen in breast cancer, but not in NSCLC, GBM, bladder or uterine cancers. Conclusions: MDM2 and MDM4 amplification are negative prognostic factors in TP53-WT breast cancer while MDM4 amp is associated with reduced survival in ICB-treated NSCLC.

Final data from the phase 2a single-arm trial of SurVaxM for newly diagnosed glioblastoma

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Background: Newly diagnosed glioblastoma (nGBM) routinely treated with surgery, radiation, and temozolomide (TMZ), still result in early progression and near-universal lethality within 5 years. Tumor associated “survivin” is expressed in >95% of nGBM and targetable by SurVaxM immunotherapy. Results from the recently completed multi-center phase 2a trial of SurVaxM in nGBM are presented. Methods: nGBM patients (pts) were enrolled at 5 trial sites. Eligibility criteria included: age ≥ 18, Karnofsky performance status ≥70, IHC confirmation of survivin expression, expression of HLA-A*02, A*03, A*11 or A*24 MHC-I alleles and residual contrast enhancement of ≤1 cm3 by MRI within 72h post-resection. Pts received standard TMZ chemoradiation followed by initiation of 4 priming doses of SurVaxM (500 mcg in emulsion with Montanide ISA 51, every 2 weeks) with 100 mcg sargramostim. Maintenance doses of SurVaxM-Montanide plus sargramostim were thereafter administered every 12 weeks. Adjuvant TMZ was administered for at least 6 cycles, after at least the first dose of SurVaxM and beginning no sooner than 28 days after completion of chemoradiation. Pts were monitored by MRI every 8 weeks, and progression was assessed using modified RANO criteria. The primary endpoint was 70% progression free survival (PFS) at 6 mos. Primary analyses of median PFS (mPFS) and median overall survival (OS) were measured from first immunization. Safety, tolerability, and immune responsiveness were also determined. Results: 63 pts with nGBM were enrolled, comprised of 38 males and 25 females with a median age of 60 years. The cohort was consistent with the 4 commonly observed primary molecular GBM subtypes (classical, mesenchymal, neural and proneural). SurVaxM was well tolerated, with no serious adverse events. A strong positive correlation, accounting for censoring, was observed between PFS and OS of all pts (r = 0.79; 95% CI (0.66,0.87)). SurVaxM was immunogenic and produced survivin-specific CD8+ T-cells and antibody (IgG) titers in both methylated and unmethylated MGMT pts and both groups showed clinical benefit. Conclusions: SurVaxM appeared to be safe and well-tolerated in pts with nGBM. SurVaxM was effective at stimulating survivin-specific immune responses and the primary endpoint was met. SurVaxM represents a promising therapy for nGBM, including for those pts with unmethylated MGMT genes. For pts treated with SurVaxM, PFS may be an acceptable surrogate for OS. Clinical trial information: NCT02455557. [Table: see text]

Study protocol for OptimalTTF-2: enhancing Tumor Treating Fields with skull remodeling surgery for first recurrence glioblastoma: a phase 2, multi-center, randomized, prospective, interventional trial

BACKGROUND

OptimalTTF-2 is a randomized, comparative, multi-center, investigator-initiated, interventional study aiming to test skull remodeling surgery in combination with Tumor Treating Fields therapy (TTFields) and best physicians choice medical oncological therapy for first recurrence in glioblastoma patients. OptimalTTF-2 is a phase 2 trial initiated in November 2020. Skull remodeling surgery consists of five burrholes, each 15 mm in diameter, directly over the tumor resection cavity. Preclinical research indicates that this procedure enhances the effect of Tumor Treating Fields considerably. We recently concluded a phase 1 safety/feasibility trial that indicated improved overall survival and no additional toxicity. This phase 2 trial aims to validate the efficacy of the proposed intervention.

METHODS

The trial is designed as a comparative, 1:1 randomized, minimax two-stage phase 2 with an expected 70 patients to a maximum sample size of 84 patients. After 12-months follow-up of the first 52 patients, an interim futility analysis will be performed. The two trial arms will consist of either a) TTFields therapy combined with best physicians choice oncological treatment (control arm) or b) skull remodeling surgery, TTFields therapy and best practice oncology (interventional arm). Major eligibility criteria include age ≥ 18 years, 1st recurrence of supratentorial glioblastoma, Karnofsky performance score ≥ 70, focal tumor, and lack of significant co-morbidity. Study design aims to detect a 20% increase in overall survival after 12 months (OS12), assuming OS12 = 40% in the control group and OS12 = 60% in the intervention group. Secondary endpoints include hazard rate ratio of overall survival and progression-free survival, objective tumor response rate, quality of life, KPS, steroid dose, and toxicity. Toxicity, objective tumor response rate, and QoL will be assessed every 3rd month. Endpoint data will be collected at the end of the trial, including the occurrence of suspected unexpected serious adverse reactions (SUSARs), unacceptable serious adverse events (SAEs), withdrawal of consent, or loss-to-follow-up.

DISCUSSION

New treatment modalities are highly needed for first recurrence glioblastoma. Our proposed treatment modality of skull remodeling surgery, Tumor Treating Fields, and best practice medical oncological therapy may increase overall survival significantly.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT0422399 , registered 13. January 2020.

Tumor Treating Fields for Ovarian Carcinoma: A Modeling Study

Purpose

Since the inception of tumor treating fields (TTFields) therapy as a Food and Drug Administration–approved treatment with known clinical efficacy against recurrent and newly diagnosed glioblastoma, various in silico modeling studies have been performed in an effort to better understand the distribution of applied electric fields throughout the human body for various malignancies or metastases.

Methods and Materials

Postacquisition attenuation-corrected positron emission tomography–computed tomography image data sets from 2 patients with ovarian carcinoma were used to fully segment various intrapelvic and intra-abdominal gross anatomic structures. A 3-dimensional finite element mesh model was generated and then solved for the distribution of applied electric fields, rate of energy deposition, and current density at the clinical target volumes (CTVs) and other intrapelvic and intra-abdominal structures. Electric field-volume histograms, specific absorption rate–volume histograms, and current density-volume histograms were generated, by which plan quality metrics were derived from and used to evaluate relative differences in field coverage between models under various conditions.

Results

TTFields therapy distribution throughout the pelvis and abdomen was largely heterogeneous, where specifically the field intensity at the CTV was heavily influenced by surrounding anatomic structures as well as its shape and location. The electric conductivity of the CTV had a direct effect on the field strength within itself, as did the position of the arrays on the surface of the pelvis and/or abdomen.

Conclusion

The combined use of electric field-volume histograms, specific absorption rate-volume histograms, current density-volume histograms, and plan quality metrics enables a personalized method to dosimetrically evaluate patients receiving TTFields therapy for ovarian carcinoma when certain patient- and tumor-specific factors are integrated with the treatment plan.

Parkinsonism reversed from treatment of pineal non-germinomatous germ cell tumor

Background:

Parkinsonism is a rare complication of non-germinomatous germ cell tumors (NGGCTs) arising from the pineal region.

Case Description:

We describe a 23-year-old man who presented with Parinaud syndrome, fatigue, and hypersomnia that were caused by a pineal region NGGCT with yolk sac component and an initial α-fetoprotein (AFP) of 1011.0 ng/ml. MRI revealed that the tumor was causing 10 mm of midline shift and compressing the cerebral aqueduct, the left thalamus, and the midbrain. Obstructive hydrocephalus was relieved by ventriculoperitoneal shunting. Six cycles of induction chemotherapy with ifosfamide, carboplatin, and etoposide reduced tumor size and decreased AFP levels in both serum and cerebrospinal fluid. Following the first cycle, the patient developed asymmetric, bilateral Parkinsonism consisting of bradykinesia, bradyphrenia, facial hypomimia, drooling, and dysphagia. Levodopa, amantadine, and methylphenidate were administered and resulted in symptom improvement. Second look neurosurgery revealed residual yolk sac tumor and a second induction regimen of gemcitabine, paclitaxel, and oxaliplatin was administered for rising AFP. The patient eventually received an autologous bone marrow transplant using a regimen of high-dose carboplatin, thiotepa, and etoposide with concomitant colony-stimulating factor and romiplostim support followed by consolidative proton craniospinal radiotherapy. Posttreatment head MRI showed that no evidence of tumor growth and serum AFP was within normal limits. His Parkinsonism eventually resolved and he was weaned off all dopaminergic drugs.

Conclusion:

Bilateral Parkinsonism from NGGCT in this patient is probably caused by pressure on nigrostriatal tracts, substantia nigra, or both. The Parkinsonian symptoms can be reversed by aggressive treatment of the tumor and administration of dopaminergic drugs.

Tumor Treating Fields for Glioblastoma Therapy During the COVID-19 Pandemic

Background

The COVID-19 pandemic has placed excessive strain on health care systems and is especially evident in treatment decision-making for cancer patients. Glioblastoma (GBM) patients are among the most vulnerable due to increased incidence in the elderly and the short survival time. A virtual meeting was convened on May 9, 2020 with a panel of neuro-oncology experts with experience using Tumor Treating Fields (TTFields). The objective was to assess the risk-to-benefit ratio and provide guidance for using TTFields in GBM during the COVID-19 pandemic.

Panel Discussion

Topics discussed included support and delivery of TTFields during the COVID-19 pandemic, concomitant use of TTFields with chemotherapy, and any potential impact of TTFields on the immune system in an intrinsically immunosuppressed GBM population. Special consideration was given to TTFields' use in elderly patients and in combination with radiotherapy regimens. Finally, the panel discussed the need to better capture data on COVID-19positive brain tumor patients to analyze longitudinal outcomes and changes in treatment decision-making during the pandemic.

Expert Opinion

TTFields is a portable home-use device which can be managed via telemedicine and safely used in GBM patients during the COVID-19 pandemic. TTFields has no known immunosuppressive effects which is important during a crisis where other treatment methods might be limited, especially for elderly patients with multiple co-morbidities. It is too early to estimate the full impact of COVID-19 on the global healthcare system and on patient outcomes and the panel strongly recommended collaboration with existing cancer COVID-19 registries to follow CNS tumor patients.

Rapid Progressive Glioblastoma despite Radiation in a Patient with Myelodysplastic Syndrome

The rapidity of glioblastoma progression can be exacerbated by impaired systemic immune surveillance. We describe an elderly woman with advanced 5q– myelodysplastic syndrome (MDS) associated with trilineage dysfunction in hematopoiesis. She also developed multiple solid tumor malignancies including ER/PR-positive and HER2-negative breast cancer, probable lung cancer without histologic confirmation, and primary glioblastoma with a high proliferation index of 80%. Because of low platelet counts of 20,000–30,000/µL that required periodic transfusion and a reduced white cell count of 600–900/µL, she was deemed unsafe to take concomitant daily temozolomide during radiation and her glioblastoma was treated with a shortened course of radiotherapy alone. Her baseline absolute neutrophil count was 110–390/µL, and CD4⁺ and CD8⁺ lymphocyte counts were 235/µL and 113/µL, respectively. During the last week of radiation, the patient developed a nonfluent aphasia, increased fatigue, and aspiration pneumonia. A gadolinium-enhanced head MRI, obtained 2 days after completion of radiation and 39 days after biopsy, demonstrated near tripling of the size of the left frontal tumor with a significant amount of adjacent cerebral edema. This case raises the possibility that advanced MDS is a negative immunomodulatory condition that can accelerate glioblastoma progression.

Leukopenia is a biomarker for effective temozolomide dosing and predicts overall survival of patients with glioblastoma

The median survival time of patients with glioblastoma is 14-16 months with a 5-year overall survival rate of 9.8%. Standard of care treatment includes radiation with concomitant temozolomide followed by cyclic temozolomide. If the patient develops myelosuppression (thrombocytopenia, leukopenia or anemia), the dose of temozolomide is reduced or stopped to avoid bleeding or infections. Recent studies have demonstrated that mild leukopenia is associated with increased overall survival in patients with glioblastoma. To confirm prior results showing that leukopenia is associated with increased overall survival as a primary outcome in patients with glioblastoma, the present study retrospectively collected complete blood counts from 141 patients with glioblastoma treated at the Beth Israel Deaconess Medical Center (Boston, USA) between January 2012 and December 2017. According to Kaplan-Meier analysis with a log-rank test, the presence of leukopenia was associated with increased overall survival (P=0.008). Furthermore, patients with grade 2 leukopenia (Common Terminology Criteria for Adverse Events version 5.0) survived longer than those without myelosuppression (P=0.024). There was no difference in overall survival between patients with grade 1, 3 or 4 leukopenia and those without myelosuppression. Leukopenia was associated with longer survival independent of age or extent of surgery in Cox proportional hazards regression modeling (P=0.00205). A possible interpretation is that grade 2 leukopenia is a biomarker of adequate temozolomide dosing in a population with diverse DNA repair function, which may be the consequence of variable O⁶-methylguanine-DNA methyltransferase activity. A prospective dose escalation trial is necessary to determine if treatment-induced leukopenia is beneficial for all patients receiving temozolomide.

Exploring Predictors of Response to Dacomitinib in EGFR-Amplified Recurrent Glioblastoma

PURPOSE

Despite the high frequency of EGFR genetic alterations in glioblastoma (GBM), EGFR-targeted therapies have not had success in this disease. To improve the likelihood of efficacy, we targeted adult patients with recurrent GBM enriched for EGFR gene amplification, which occurs in approximately half of GBM, with dacomitinib, a second-generation, irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that penetrates the blood-brain barrier, in a multicenter phase II trial.

PATIENTS AND METHODS

We retrospectively explored whether previously described EGFR extracellular domain (ECD)-sensitizing mutations in the context of EGFR gene amplification could predict response to dacomitinib, and in a predefined subset of patients, we measured post-treatment intratumoral dacomitinib levels to verify tumor penetration.

RESULTS

We found that dacomitinib effectively penetrates contrast-enhancing GBM tumors. Among all 56 treated patients, 8 (14.3%) had a clinical benefit as defined by a duration of treatment of at least 6 months, of whom 5 (8.9%) remained progression free for at least 1 year. Presence of EGFRvIII or EGFR ECD missense mutation was not associated with clinical benefit. We evaluated the pretreatment transcriptome in circulating extracellular vesicles (EVs) by RNA sequencing in a subset of patients and identified a signature that distinguished patients who had durable benefit versus those with rapid progression.

CONCLUSION

While dacomitinib was not effective in most patients with EGFR-amplified GBM, a subset experienced a durable, clinically meaningful benefit. Moreover, EGFRvIII and EGFR ECD mutation status in archival tumors did not predict clinical benefit. RNA signatures in circulating EVs may warrant investigation as biomarkers of dacomitinib efficacy in GBM.

Tumor treating fields in neuro-oncology: integration of alternating electric fields therapy into promising treatment strategies

As the most recent innovation in cancer therapy that utilizes properties of the electromagnetic spectrum, tumor treating fields (TTFields) are non-invasive alternating electrical fields that target rapidly dividing tumor cells. In the patient, TTFields are delivered as regional treatment via two pairs of orthogonally positioned transducer arrays applied to the head or elsewhere on the body surface. Side effects are primarily localized to the skin. Since the initial proof-of-concept study published in 2007, the use of TTFields has become integrated into the standard-of-care multi-modality treatment of glioblastoma (GBM). In this review, we summarize the theory behind TTFields and describe how key mechanistic data helped guide pivotal clinical trials. We also highlight potential future applications.

Finite element analysis of Tumor Treating Fields in a patient with posterior fossa glioblastoma

Introduction

Tumor Treating Fields (TTFields) are alternating electric fields at 200 kHz that disrupt tumor cells as they undergo mitosis. Patient survival benefit has been demonstrated in randomized clinical trials but much of the data are available only for supratentorial glioblastomas. We investigated a series of alternative array configurations for the posterior fossa to determine the electric field coverage of a cerebellar glioblastoma.

Methods

Semi-automated segmentation of neuro-anatomical structures was performed while the gross tumor volume (GTV) was manually delineated. A three-dimensional finite-element mesh was generated and then solved for field distribution.

Results

Compared to the supratentorial array configuration, the alternative array configurations consist of posterior displacement the 2 lateral opposing arrays and inferior displacement of the posteroanterior array, resulting in an average increase of 46.6% electric field coverage of the GTV as measured by the area under the curve of the electric field-volume histogram (E_AUC). Hotspots, or regions of interest with the highest 5% of TTFields intensity (E_5%), had an average increase of 95.6%. Of the 6 posterior fossa configurations modeled, the PA_Horizontal arrangement provided the greatest field coverage at the GTV when the posteroanterior array was placed centrally along the patient’s posterior neck and horizontally parallel, along the longer axis, to the coronal plane of the patient’s head. Varying the arrays also produced hotspots proportional to TTFields coverage.

Conclusions

Our finite element modeling showed that the alternative array configurations offer an improved TTFields coverage to the cerebellar tumor compared to the conventional supratentorial configuration.

The ESCRT-III Protein CHMP1A Mediates Secretion of Sonic Hedgehog on a Distinctive Subtype of Extracellular Vesicles

Endosomal sorting complex required for transport (ESCRT) complex proteins regulate biogenesis and release of extracellular vesicles (EVs), which enable cell-to-cell communication in the nervous system essential for development and adult function. We recently showed human loss-of-function (LOF) mutations in ESCRT-III member CHMP1A cause autosomal recessive microcephaly with pontocerebellar hypoplasia, but its mechanism was unclear. Here, we show Chmp1a is required for progenitor proliferation in mouse cortex and cerebellum and progenitor maintenance in human cerebral organoids. In Chmp1a null mice, this defect is associated with impaired sonic hedgehog (Shh) secretion and intraluminal vesicle (ILV) formation in multivesicular bodies (MVBs). Furthermore, we show CHMP1A is important for release of an EV subtype that contains AXL, RAB18, and TMED10 (ART) and SHH. Our findings show CHMP1A loss impairs secretion of SHH on ART-EVs, providing molecular mechanistic insights into the role of ESCRT proteins and EVs in the brain.

Extracellular vesicles (EVs) are essential for cell-to-cell communication in developing brain. Coulter et al. show that the human microcephaly gene CHMP1A is required for neuroprogenitor proliferation through regulation of vesicular secretion of the growth factor sonic hedgehog (SHH). CHMP1A specifically impairs SHH secretion on a distinctive EV subtype, ART-EV.

Severe isopropanolemia without acetonemia or clinical manifestations of isopropanol intoxication

This is the first reported case of severe isopropanolemia in a patient who did not experience associated clinical manifestations and acetonemia. The patient was found lying face down in a hotel lobby but at admission was alert and oriented to place and person. Toxicological analysis of the patient's serum revealed the presence of isopropanol at a concentration of 72 mmol/L. An increased serum osmolal gap (81 mOsm/kg) was also observed. The serum concentration of isopropanol decreased to 9.5 mmol/L 15.5 h after admission with an estimated half-life of elimination of 5-7 h. No serum acetone was detected throughout the patient's hospitalization. The identity of isopropanol was confirmed by gas chromatography/mass spectrometry. The patient remained awake and alert while in the hospital and was discharged 5 days after admission. These unusual findings raise some fundamental questions about the role of isopropanol conversion to acetone in the manifestation of symptoms usually associated with isopropanol intoxication.

Kinetic serum creatinine assays. II. A critical evaluation and review

We have evaluated the Technicon AutoAnalyzer method, the Beckman Creatinine Analyzer II, DuPont aca, Electro-Nucleonics GEMSAEC, and Instrumentation Laboratory Model 916 kinetic methods for determination of serum creatinine. These methods, which involve the Jaffé reaction, all showed a statistically significant proportional error relative to an ion-exchange pretreatment method for creatinine in 92 serum samples; the GEMSAEC method also showed a bias. The positive interference of several acid metabolites was quantitated in each of the methods. The evidence indicates that bilirubin, although associated with a negative creatinine interference, is not the sole interferent. We determined the magnitude of this interference and studied several methods for minimizing it.

SurVaxM with standard therapy in newly diagnosed glioblastoma: Phase II trial update

2016

Background: SVN53-67/M57-KLH (SurVaxM) is a novel cancer vaccine designed to stimulate an immune response targeting the tumor-specific antigen survivin. A multi-center, single-arm phase 2 clinical trial of SurVaxM in survivin-positive newly diagnosed glioblastoma (nGBM, NCT02455557) is now fully enrolled and data updated. Methods: Patients (n = 63) with nGBM were enrolled at 5 US cancer centers and followed for safety, 6-month progression-free survival (PFS6), 12-month overall survival (OS12) and immunologic response. All patients underwent craniotomy with near-total resection ( < 1 cm3 residual contrast enhancement), TMZ chemoradiation, adjuvant TMZ and SurVaxM. Patients received 4 doses of SurVaxM (500 mcg) in Montanide with sargramostim (100 mcg) biweekly, followed by maintenance SurVaxM with adjuvants every 12 weeks until tumor progression. Immunogenicity of SurVaxM was assessed by detection of survivin-specific antibody (IgG) and CD8+ T-cell levels. Results: Median age was 60 yrs (range, 20-82), 53% methylated MGMT, 46% unmethylated MGMT (1 N/A) and 60% were male. Survivin expression ranged from 1-40% (median 12%) by immunohistochemistry. Median time to first immunization was 3.0 mo (1.9-4.0 mo) from diagnosis. There have been no RLT or grade ≥ 3 SAE attributable to SurVaxM. The most common AE was grade 1-2 injection site reactions. OS12 was 86% from first immunization and 93.4% from diagnosis. OS12 for meMGMT was 93.1% and unMGMT was 78% from first immunization. Median time to tumor progression (mPFS) was 13.9 months from diagnosis. Median OS has not yet been reached. SurVaxM produced an increase in survivin-specific IgG titre from pre-vaccine baseline to ≥ 1:10,000 in 67% of pts and ≥ 1:100,000 in 27%. CD8+ T cell responses were observed. Anti-survivin IgG and OS were correlated. Conclusions: SurVaxM immunotherapy generated encouraging efficacy and immunogenicity in nGBM and has minimal toxicity. A randomized, prospective trial of SurVaxM in nGBM is planned. Clinical trial information: NCT024455557.

Quantitative ultrasound of muscle can detect corticosteroid effects

OBJECTIVES

In this study, we sought to determine whether quantitative ultrasound (QUS) could detect the impact of corticosteroids on muscle in the absence of frank weakness.

METHODS

QUS was performed on selected limb muscles of 20 brain tumor patients treated with dexamethasone and 30 healthy controls. Echointensity was quantified using gray scale level (GSL) analysis and compared between groups; correlation to corticosteroid exposure was also performed.

RESULTS

Average 4-muscle GSL (±standard deviation) was greater in patients compared to controls (35.5 ± 5.61 arbitrary units (AU) versus 30.4 ± 4.17 AU, p = 0.001), with the greatest differences in tibialis anterior. Average muscle GSL also correlated to length of corticosteroid therapy (rho = 0.52, p = 0.01).

CONCLUSIONS

These findings suggest that QUS may be able to quantify skeletal muscle alterations associated with chronic corticosteroid use. Further study of this approach is warranted.

SIGNIFICANCE

The findings of this study may provide a tool to evaluate corticosteroid myopathy.

The Clinical Application of Tumor Treating Fields Therapy in Glioblastoma

Glioblastoma is the most common and lethal form of brain cancer, with a median survival of 15 months after diagnosis and a 5 year survival rate of only 5% with current standard of care. Tumors often recur within 9 months following initial surgery, radiation and chemotherapy, at which point treatment options become limited. This highlights the pressing need for the development of better therapeutics to prolong survival and increase the quality of life for these patients. Tumor Treating Fields (TTFields) therapy was developed to take advantage of the effect of low frequency alternating electrical fields on cells for cancer therapy. TTFields have been demonstrated to disrupt cells during mitosis and slow tumor growth. There is also growing evidence that they act through stimulating immune responses within exposed tumors. The advantages of TTFields therapy include its noninvasive approach and increased quality of life compared to other treatment modalities such as cytotoxic chemotherapies. The Food and Drug Administration approved TTFields therapy for the treatment of recurrent glioblastoma in 2011 and for newly diagnosed glioblastoma in 2015. We report on the effects of TTFields during mitosis, the results of electric fields modeling, and proper transducer array placement. Our protocol outlines the clinical application of TTFields on a patient post-surgery, using the second-generation device.

Nucleolin Is a Functional Binding Protein for Salinomycin in Neuroblastoma Stem Cells

The aim of this study is to illuminate a novel therapeutic approach by identifying a functional binding target of salinomycin, an emerging anticancer stem cell (CSC) agent, and to help dissect the underlying action mechanisms. By utilizing integrated strategies, we identify that nucleolin (NCL) is likely a salinomycin-binding target and a critical regulator involved in human neuroblastoma (NB) CSC activity. Salinomycin markedly suppresses NB CD34 expression and reduces CD34+ cell population in an NCL-dependent manner via disruption of the interaction of NCL with CD34 promoter. The elevated levels of NCL expression in NB tumors are associated with poor patient survival. Altogether, these results indicate that NCL is likely a novel functional salinomycin-binding target that exhibits the potential to be a prognostic marker for NB therapy.

Identification of a panel of genes as a prognostic biomarker for glioblastoma

Background

Glioblastoma multiforme (GBM) is a fatal disease without effective therapy. Identification of new biomarkers for prognosis would enable more rational selections of strategies to cure patients with GBM and prevent disease relapse.

Methods

Seven datasets derived from GBM patients using microarray or next generation sequencing in R2 online database (http://r2.amc.nl) were extracted and then analyzed using JMP software. The survival distribution was calculated according to the Kaplan-Meier method and the significance was determined using log-rank statistics. The sensitivity of a panel of GBM cell lines in response to temozolomide (TMZ), salinomycin, celastrol, and triptolide treatments was evaluated using MTS and tumor-sphere formation assay.

Findings

We identified that CD44, ATP binding cassette subfamily C member 3 (ABCC3), and tumor necrosis factor receptor subfamily member 1A (TNFRSF1A) as highly expressed genes in GBMs are associated with patients' poor outcomes and therapy resistance. Furthermore, these three markers combined with MGMT, a conventional GBM marker, can classify GBM patients into five new subtypes with different overall survival time in response to treatment. The four-gene signature and the therapy response of GBMs to a panel of therapeutic compounds were confirmed in a panel of GBM cell lines.

Interpretation

The data indicate that the four-gene panel can be used as a therapy response index for GBM patients and potential therapeutic targets. These results provide important new insights into the early diagnosis and the prognosis for GBM patients and introduce potential targets for GBM therapeutics.

Fund

Baylor Scott & White Health Startup Fund (E.W.); Collaborative Faculty Research Investment Program (CFRIP) of Baylor University, Baylor Scott & White Health, and Baylor College of Medicine (E.W., T.S., J.H.H.); NIH R01 NS067435 (J.H.H.); Scott & White Plummer Foundation Grant (J.H.H.); National Natural Science Foundation of China 816280007 (J.H.H. and Fu.W.).

Tubulin's response to external electric fields by molecular dynamics simulations

Tubulin heterodimers are the building blocks of microtubules and disruption of their dynamics is exploited in the treatment of cancer. Electric fields at certain frequencies and magnitudes are believed to do the same. Here, the tubulin dimer’s response to external electric fields was determined by atomistic simulation. External fields from 50 to 750 kV/cm, applied for 10 ns, caused significant conformational rearrangements that were dependent upon the field’s directionality. Charged and flexible regions, including the α:H1-B2 loop, β:M-loop, and C-termini, were susceptible. Closer inspection of the α:H1-B2 loop in lower strength fields revealed that these effects were consistent and proportional to field strength, and the findings indicate that external electric fields modulate the stability of microtubules through conformational changes to key loops involved in lateral contacts. We also find evidence that tubulin’s curvature and elongation are affected, and external electric fields may bias tubulin towards depolymerization.

Alternating Electric Fields Therapy for Malignant Gliomas: From Bench Observation to Clinical Reality

Alternating electric fields of intermediate frequencies, also known as Tumor Treating Fields (TTFields or TTF) is a novel anticancer treatment modality that disrupts tumor cell mitosis at the metaphase-anaphase transition, leading to mitotic catastrophe, aberrant mitotic exit, and/or cell death. It is realized through alteration of the cytokinetic cleavage furrow by interference of proteins possessing large dipole moments, like septin heterotrimer complex and α/β-tubulin, and that results in disordered membrane contraction and failed cytokinesis. Aberrant mitotic exit also elicits immunogenic cell death, which may potentiate an immune response against treated tumors. Notably, in patients with recurrent glioblastoma multiforme (GBM) a prospective clinical trial demonstrated comparable overall survival and progression-free survival after TTFields therapy and best physician's choice chemotherapy. Moreover, it was shown that in patients with newly diagnosed GBM initially treated with standard chemoradiotherapy with daily temozolomide (TMZ), adjuvant TTFields combined with TMZ offered better survival than adjuvant TMZ alone. Therefore, TTFields therapy can be appreciated as a standard treatment option in cases of intracranial malignant gliomas, whereas future studies should establish its optimal combination with other existing anticancer modalities, which may offer additional survival benefits for patients.

Abstract 2284: Semiautomated MRI segmentation workflow for glioblastoma treated by Tumor Treating Fields

Background: Tumor Treating Fields (TTFields) therapy is an approved modality of treatment for glioblastoma. Patient anatomy-based finite element analysis (FEA) has the potential to reveal not only how these fields affect tumor control but also how they can be optimized to improve efficacy. Historically, this has been achieved with manual segmentation by an expert familiar with intracranial neuroanatomic structures, but this method is time-consuming, financially costly, and highly variable between individuals. While the availability of tools for segmenting MRIs obviates some of these obstacles, creating FEA models requires manual adjustments, including removal of disconnected voxels, incorporation of unsegmented structures that may alter the electric field, and addition of 36 electrodes matching those of the transducers on the scalp. Existing approaches are also not scalable to a large number of patient MRI scans.

Methods: Patient anatomy-based FEA models were created by segmenting MRI images—using the NewSegment algorithm from Statistical Paramedic Mapping 8 (SPM8)—into tissue “masks” using ScanIP from Simpleware (Exeter, UK). The electric properties of each tissue were applied to these masks in silico using COMSOL Multiphysics (Burlington, MA). The fidelity of the segmentations was compared using the Dice coefficient, and COMSOL generated electric field maps were compared for models with and without post-processing in ScanIP.

Results: A semiautomated workflow was developed to prepare FEA models for TTFields with fully automated electrode placement. The workflow encompassed image preprocessing, co-registration, segmentation, post-processing and mesh generation in ScanIP. Modified extended tissue probability maps were used to segment cerebellum and orbits in addition to white matter, gray matter, cerebrospinal fluid, skull, and scalp. Further automated post-processing in ScanIP cleaned up disconnected voxels, smoothed surfaces, and layered the masks to prevent erroneous boundary conditions. The Dice coefficient was greater for the model with ScanIP post-processing, as compared to the segmentations resulting from SPM8 NewSegment alone. COMSOL-generated electric field maps also displayed differences when models were generated with post-processing in ScanIP compared to those without.

Conclusions: These software and workflow may be used to accelerate the investigation of TTFields in patients by facilitating the creation of FEA models, like electric field maps, derived from patient MRI.

Citation Format: Joshua J. Timmons, Ed Lok, Pyay San, Kevin Bui, Eric T. Wong. Semiautomated MRI segmentation workflow for glioblastoma treated by Tumor Treating Fields [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2284.

Abstract 1707: Tumor treating fields exert cellular and immunologic effects

While there is clear clinical evidence to support the therapeutic efficacy of low dose alternating electric fields (TTFields) in treating glioblastoma, their intracellular targets and mechanism of action remains poorly defined. Historically, TTFields have been thought to operate by inducing extensive plasma membrane blebbing during the entry into anaphase resulting in aberrant mitotic exit and cell death. However, we have found that cells exposed to TTFields exhibited increased granularity and evidence of endoplasmic reticulum stress and genotoxic stress suggesting other mechanisms to explain their clinical efficacy. Cells exposed to TTFields exhibited reductions in levels of culture media acidification and analysis of intracellular metabolism showed evidence for an increase in mitochondrial respiration and glutaminolysis pathway. Our previous analysis of data from the pivotal phase III EF-11 clinical trial showed that increased corticosteroid use was strongly correlated with poor outcomes in TTFields-treated patients, possibly by suppressing immune effector function required for to drive tumor regression. TTFields drives the cell surface expression of immune stimulatory stress marker proteins calreticulin, and the secretion of the Alarmin/DAMP protein, HMGB1 which are together suggest that TTFields can stimulate immunogenic cell death. Co-culture of bone marrow derived macrophages with TTFields-treated CT26 cells resulted in the up-regulation of cell surface activation markers in the macrophage population that was blocked by a monoclonal antibody directed against HMGB1. Further, supernatants from these co-cultures contained increased levels of pro-inflammatory cytokines and chemokines and a reduction of anti-inflammatory cytokines associated with the presence of the TTFields-treated cells relative to co-cultures containing naïve tumor cells. Further, in vivo, engrafted Lewis lung carcinoma tumors exhibited increased levels of granzyme positive cells following TTFields treatment. Together, these data suggest that TTFields affect cancer cells during interphase and this insult leads to alterations in cancer cell metabolism and increased tumor cell immunogenicity and thus act to drive increased immune recognition and tumor rejection. In patients, these effects are likely to be opposed by the immune suppressive functions within the tumor microenvironment and corticosteroid use. Therefore, this model of TTFields action may provide a therapeutically rational base to devise improved TTFields treatment strategies from.

Citation Format: Eric T. Wong, Joshua Timmons, Kenneth D. Swanson. Tumor treating fields exert cellular and immunologic effects [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1707.

End-to-end workflow for finite element analysis of tumor treating fields in glioblastomas

Tumor Treating Fields (TTFields) therapy is an approved modality of treatment for glioblastoma. Patient anatomy-based finite element analysis (FEA) has the potential to reveal not only how these fields affect tumor control but also how to improve efficacy. While the automated tools for segmentation speed up the generation of FEA models, multi-step manual corrections are required, including removal of disconnected voxels, incorporation of unsegmented structures and the addition of 36 electrodes plus gel layers matching the TTFields transducers. Existing approaches are also not scalable for the high throughput analysis of large patient volumes. A semi-automated workflow was developed to prepare FEA models for TTFields mapping in the human brain. Magnetic resonance imaging (MRI) pre-processing, segmentation, electrode and gel placement, and post-processing were all automated. The material properties of each tissue were applied to their corresponding mask in silico using COMSOL Multiphysics (COMSOL, Burlington, MA, USA). The fidelity of the segmentations with and without post-processing was compared against the full semi-automated segmentation workflow approach using Dice coefficient analysis. The average relative differences for the electric fields generated by COMSOL were calculated in addition to observed differences in electric field-volume histograms. Furthermore, the mesh file formats in MPHTXT and NASTRAN were also compared using the differences in the electric field-volume histogram. The Dice coefficient was less for auto-segmentation without versus auto-segmentation with post-processing, indicating convergence on a manually corrected model. An existent but marginal relative difference of electric field maps from models with manual correction versus those without was identified, and a clear advantage of using the NASTRAN mesh file format was found. The software and workflow outlined in this article may be used to accelerate the investigation of TTFields in glioblastoma patients by facilitating the creation of FEA models derived from patient MRI datasets.

Analysis of physical characteristics of Tumor Treating Fields for human glioblastoma

Tumor Treating Fields (TTFields) therapy is an approved treatment that has known clinical efficacy against recurrent and newly diagnosed glioblastoma. However, the distribution of the electric fields and the corresponding pattern of energy deposition in the brain are poorly understood. To evaluate the physical parameters that may influence TTFields, postacquisition MP-RAGE, T1 and T2 MRI sequences from a responder with a right parietal glioblastoma were anatomically segmented and then solved using finite-element method to determine the distribution of the electric fields and rate of energy deposition at the gross tumor volume (GTV) and other intracranial structures. Electric field-volume histograms (EVH) and specific absorption rate-volume histograms (SARVH) were constructed to numerically evaluate the relative and/or absolute magnitude volumetric differences between models. The electric field parameters E_AUC , V_E150 , E_95% , E_50% , and E_20% , as well as the SAR parameters SAR_AUC , V_SAR7.5 , SAR_95% , SAR_50% , and SAR_20% , facilitated comparisons between models derived from various conditions. Specifically, TTFields at the GTV were influenced by the dielectric characteristics of the adjacent tissues as well as the GTV itself, particularly the presence or absence of a necrotic core. The thickness of the cerebrospinal fluid on the convexity of the brain and the geometry of the tumor were also relevant factors. Finally, the position of the arrays also influenced the electric field distribution and rate of energy deposition in the GTV. Using EVH and SARVH, a personalized approach for TTFields treatment can be developed when various patient-related and tumor-related factors are incorporated into the planning procedure.

Using Anatomic Magnetic Resonance Image Information to Enhance Visualization and Interpretation of Functional Images: A Comparison of Methods Applied to Clinical Arterial Spin Labeling Images

Functional imaging provides hemodynamic and metabolic information and is increasingly being incorporated into clinical diagnostic and research studies. Typically functional images have reduced signal-to-noise ratio and spatial resolution compared to other non-functional cross sectional images obtained as part of a routine clinical protocol. We hypothesized that enhancing visualization and interpretation of functional images with anatomic information could provide preferable quality and superior diagnostic value. In this work, we implemented five methods (frequency addition, frequency multiplication, wavelet transform, nonsubsampled contourlet transform and intensity-hue-saturation) and a newly proposed ShArpening by Local Similarity with Anatomic images (SALSA) method to enhance the visualization of functional images, while preserving the original functional contrast and quantitative signal intensity characteristics over larger spatial scales. Arterial spin labeling blood flow MR images of the brain were visualization enhanced using anatomic images with multiple contrasts. The algorithms were validated on a numerical phantom and their performance on images of brain tumor patients were assessed by quantitative metrics and neuroradiologist subjective ratings. The frequency multiplication method had the lowest residual error for preserving the original functional image contrast at larger spatial scales (55%-98% of the other methods with simulated data and 64%-86% with experimental data). It was also significantly more highly graded by the radiologists (p<0.005 for clear brain anatomy around the tumor). Compared to other methods, the SALSA provided 11%-133% higher similarity with ground truth images in the simulation and showed just slightly lower neuroradiologist grading score. Most of these monochrome methods do not require any prior knowledge about the functional and anatomic image characteristics, except the acquired resolution. Hence, automatic implementation on clinical images should be readily feasible.

Phase I study of low-dose metronomic temozolomide for recurrent malignant gliomas

Background

The treatment goal for recurrent malignant gliomas centers on disease stabilization while minimizing therapy-related side effects. Metronomic dosing of cytotoxic chemotherapy has emerged as a promising option to achieve this objective.

Methods

This phase I study was performed using metronomic temozolomide (mTMZ) at 25 or 50 mg/m²/day continuously in 42-day cycles. Correlative studies were incorporated using arterial spin labeling MRI to assess tumor blood flow, analysis of matrix metalloproteinase-2 (MMP-2) and MMP-9 activities in the cerebrospinal fluid (CSF) as surrogates for tumor angiogenesis and invasion, as well as determination of CSF soluble interleukin-2 receptor alpha (sIL-2Rα) levels as a marker of immune modulation.

Results

Nine subjects were enrolled and toxicity consisted of primarily grade 1 or 2 hematological and gastrointestinal side effects; only one patient had a grade 3 elevated liver enzyme level that was reversible. Tumor blood flow was variable across subjects and time, with two experiencing a transient increase before a decrease to below baseline level while one exhibited a gradual drop in blood flow over time. MMP-2 activity correlated with overall survival but not with progression free survival, while MMP-9 activity did not correlate with either outcome parameters. Baseline CSF sIL-2Rα level was inversely correlated with time from initial diagnosis to first progression, suggesting that subjects with higher sIL-2Rα may have more aggressive disease. But they lived longer when treated with mTMZ, probably due to drug-related changes in T-cell constituency.

Conclusions

mTMZ possesses efficacy against recurrent malignant gliomas by altering blood flow, slowing invasion and modulating antitumor immune function.

Injection of Syngeneic Murine Melanoma Cells to Determine Their Metastatic Potential in the Lungs

Approximately 90% of human cancer deaths are linked to metastasis. Despite the prevalence and relative harm of metastasis, therapeutics for treatment or prevention are lacking. We report a method for the establishment of pulmonary metastases in mice, useful for the study of this phenomenon. Tail vein injection of B57BL/6J mice with B16-BL6 is among the most used models for melanoma metastases. Some of the circulating tumor cells establish themselves in the lungs of the mouse, creating "experimental" metastatic foci. With this model it is possible to measure the relative effects of therapeutic agents on the development of cancer metastasis. The difference in enumerated lung foci between treated and untreated mice indicates the efficacy of metastases neutralization. However, prior to the investigation of a therapeutic agent, it is necessary to determine an optimal number of injected B16-BL6 cells for the quantitative analysis of metastatic foci. Injection of too many cells may result in an overabundance of metastatic foci, impairing proper quantification and overwhelming the effects of anti-cancer therapies, while injection of too few cells will hinder the comparison between treated and controls.

A randomized, placebo-controlled pilot trial of armodafinil for fatigue in patients with gliomas undergoing radiotherapy

BACKGROUND

Fatigue is common among glioma patients undergoing radiotherapy (RT) and impacts quality of life (QOL). We evaluated whether armodafinil, a wakefulness-promoting medication, improves fatigue in glioma patients undergoing RT.

METHODS

Eligibility criteria included age ≥18 years, Karnofsky performance status ≥60, and grade 2-4 glioma undergoing RT to a total dose of 50-60 Gy. Patients were randomized 1:1 to armodafinil or placebo for 8 weeks beginning within 10 days of starting RT. Fatigue and QOL were assessed at baseline, day 22, day 43, and day 56 with the Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-F), the Functional Assessment of Cancer Therapy - General (FACT-G), the Brief Fatigue Inventory (BFI), and the Cancer Fatigue Scale (CFS). The primary aim was to detect a difference in the 42-day change in FACIT-F fatigue subscale between the 2 groups using a 2-sample Wilcoxon statistic.

RESULTS

We enrolled 81 patients total (42 armodafinil and 39 placebo). Armodafinil did not significantly improve fatigue or QOL based on the 42-day change in FACIT-F fatigue subscale, FACT-G, CFS, or BFI. Further analysis suggests no difference between the arms even after accounting for the potential bias of missing data. Treatment was well tolerated with few grade 3 or 4 toxicities.

CONCLUSIONS

While treatment was well-tolerated, an 8-week course of armodafinil did not improve fatigue or QOL in glioma patients undergoing RT in this pilot study. Further studies are needed to determine whether pharmacologic treatment improves fatigue in glioma patients undergoing RT.

Neurological presentations of intravascular lymphoma (IVL): meta-analysis of 654 patients

Background

Patients with intravascular lymphoma (IVL) frequently have neurological signs and symptoms. Prompt diagnosis and treatment is therefore crucial for their survival. However, the spectrum of neurological presentations and their respective frequencies have not been adequately characterized. Our aim is to document the spectrum of clinical symptoms and their respective frequencies and to create a clinical framework for the prompt diagnosis of IVL.

Methods

A comprehensive meta-analysis of 654 cases of IVL published between 1957 and 2012 was performed to provide better insight into the neurological presentations of this disease. Neurologic complications were mainly divided into central nervous system (CNS) and peripheral nervous system (PNS) presentations.

Results

There were no differences in occurrences of CNS IVL based on gender or geographic locations (Asian Vs non-Asian). However, most patients with CNS IVL were younger than 70 years of age (p < 0.05). Our limited data do not support the treatment efficacy of methotrexate.

CNS symptoms were seen in 42 % of all cases. The most common CNS complications identified were cognitive impairment/dementia (60.9 %), paralysis (22.2 %), and seizures (13.4 %). PNS complications were seen in 9.5 % of cases. Out of these, muscle weakness (59.7 %), neurogenic bladder (37.1 %), and paresthesia (16.1 %) were the most common presentations.

Conclusions

CNS complications are more common among IVL patients. Out of these, dementia and seizures outnumber stroke-like presentations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-015-0509-8) contains supplementary material, which is available to authorized users.

A microRNA-1280/JAG2 network comprises a novel biological target in high-risk medulloblastoma

Over-expression of PDGF receptors (PDGFRs) has been previously implicated in high-risk medulloblastoma (MB) pathogenesis. However, the exact biological functions of PDGFRα and PDGFRβ signaling in MB biology remain poorly understood. Here, we report the subgroup specific expression of PDGFRα and PDGFRβ and their associated biological pathways in MB tumors. c-MYC, a downstream target of PDGFRβ but not PDGFRα, is involved in PDGFRβ signaling associated with cell proliferation, cell death, and invasion. Concurrent inhibition of PDGFRβ and c-MYC blocks MB cell proliferation and migration synergistically. Integrated analysis of miRNA and miRNA targets regulated by both PDGFRβ and c-MYC reveals that increased expression of JAG2, a target of miR-1280, is associated with high metastatic dissemination at diagnosis and a poor outcome in MB patients. Our study may resolve the controversy on the role of PDGFRs in MB and unveils JAG2 as a key downstream effector of a PDGFRβ-driven signaling cascade and a potential therapeutic target.

Diagnostic Accuracy of PET, SPECT, and Arterial Spin-Labeling in Differentiating Tumor Recurrence from Necrosis in Cerebral Metastasis after Stereotactic Radiosurgery

BACKGROUND AND PURPOSE

Radiographic assessment of cerebral metastasis after stereotactic radiosurgery remains a major challenge in neuro-oncology. It is often difficult to distinguish tumor progression from radiation necrosis in this setting using conventional MR imaging. The objective of this study was to compare the diagnostic sensitivity and specificity of different functional imaging modalities for detecting tumor recurrence after stereotactic radiosurgery.

MATERIALS AND METHODS

We retrospectively reviewed patients treated between 2007 and 2010 and identified 14 patients with cerebral metastasis who had clinical or radiographic progression following stereotactic radiosurgery and were imaged with arterial spin-labeling, FDG-PET, and thallium SPECT before stereotactic biopsy. Diagnostic accuracy, specificity, sensitivity, positive predictive value, and negative predictive value were calculated for each imaging technique by using the pathologic diagnosis as the criterion standard.

RESULTS

Six patients (42%) had tumor progression, while 8 (58%) developed radiation necrosis. FDG-PET and arterial spin-labeling were equally sensitive in detecting tumor progression (83%). However, the specificity of arterial spin-labeling was superior to that of the other modalities (100%, 75%, and 50%, respectively). A combination of modalities did not augment the sensitivity, specificity, positive predictive value, or negative predictive value of arterial spin-labeling.

CONCLUSIONS

In our series, arterial spin-labeling positivity was closely associated with the pathologic diagnosis of tumor progression after stereotactic radiosurgery. Validation of this finding in a large series is warranted.