Maintenance Therapy With Tumor-Treating Fields Plus Temozolomide vs Temozolomide Alone for Glioblastoma: A Randomized Clinical Trial

Treatment of glioblastoma in adults

The diagnosis of a glioblastoma is mainly made on the basis of their microscopic appearance with the additional determination of epigenetic as well as mutational analyses as deemed appropriate and taken into account in different centers. How far the recent discovery of tumor networks will stimulate novel treatments is a subject of intensive research. A tissue diagnosis is the mainstay. Regardless of age, patients should undergo a maximal safe resection. Magnetic resonance imaging is the surrogate parameter of choice for follow up. Patients should receive chemoradiotherapy with temozolomide with the radiation schedule adapted to performance status, age and tumor location. The use of temozolomide may be reconsidered according to methylguanine DNA methyltransferase (MGMT) promoter methylation status; patients with an active promoter may be subjected to a trial or further molecular work-up in order to potentially replace temozolomide; patients with an inactive (hypermethylated) MGMT promoter may be counseled for the co-treatment with the methylating and alkylating compound lomustine in addition to temozolomide. Tumor-treating fields are an additive option independent of the MGMT status. Determination of recurrence is still challenging. Patients with clinical or radiographic confirmed progression should be counseled for a second surgical intervention, that is, to reach another macroscopic removal of the tumor bulk or to obtain tissue for an updated molecular analysis. Immune therapeutic approaches may be dependent on tumor types and molecular signatures. In newly diagnosed and recurrent glioblastoma, bevacizumab prolongs progression-free survival without affecting overall survival in an unselected population of glioblastoma patients. Whether or not selection can be made on the basis of molecular or imaging parameters remains to be determined. Some patients may benefit from a second radiotherapy. In our view, the near future will provide support for translating the amazing progress in understanding the molecular background of glioblastoma in to more complex, but promising therapy concepts.

Value of the visual and semiquantitative analysis of carbon-11-methionine PET/CT in brain tumors' recurrence versus post-therapeutic changes

To compare the visual and semiquantitative analysis of carbon-11-methionine (C-MET) PET/computed tomography (CT) images in patients with primary brain tumors and suspected recurrence, persistence, or necrotic post-therapeutic changes. A total of 41 consecutive C-MET-PET/CT scans on 35 (21 men, mean age 44.1±16.6 years) patients were requested for MRI suspicion of recurrent or persistent primary tumor after therapy. The C-MET PET/CT were obtained 20 min after an intravenous injection of 555-740 MBq (15-20 mCi) of C-MET. Both visual and semiquantitative evaluations were performed comparing C-MET uptake between suspicious areas and different lesion/normal-to-background ratios. The final diagnosis was established by histological examination in 12 cases and clinical and MRI follow-up in 29 cases. Visual analyses were positive in 27 (63.4%) and negative in 14 (36.6%) of the C-MET PET/CT. The sensitivity was 83.9%, specificity was 90.0%, positive predictive value was 96.3%, negative predictive value was 64.3% and accuracy was 71.4%. For the semiquantitative analysis, all the lesion/normal-to-background ratios could differentiate between tumor and nontumor (P<0.001), the lesion/contralateral parenchyma (L/CP) maximum standardized uptake value (SUVmax) being the index with the highest area under de curve (0.938). Applying an L/CP SUVmax index of 1.21, the sensitivity was 89.3%, specificity was 90.0%, positive predictive value was 96.1%, negative predictive value was 75%, and accuracy was 82.9%. C-MET-PET/CT was a useful technique to differentiate post-therapeutic changes from tumor presence in treated patients with brain neoplasm in whom cerebral MRI is nonconclusive, showing a high diagnostic performance. Our results showed only slight differences between visual analysis methods and the L/CP SUVmax ratio, the best of the semiquantitative methods.

Effects of tumor treating fields (TTFields) on glioblastoma cells are augmented by mitotic checkpoint inhibition

Tumor treating fields (TTFields) are approved for glioblastoma (GBM) therapy. TTFields disrupt cell division by inhibiting spindle fiber formation. Spindle assembly checkpoint (SAC) inhibition combined with antimitotic drugs synergistically decreases glioma cell growth in cell culture and mice. We hypothesized that SAC inhibition will increase TTFields efficacy. Human GBM cells (U-87 MG, GaMG) were treated with TTFields (200 kHz, 1.7 V/cm) and/or the SAC inhibitor MPS1-IN-3 (IN-3, 4 µM). Cells were counted after 24, 48, and 72 h of treatment and at 24 and 72 h after end of treatment (EOT). Flow cytometry, immunofluorescence microscopy, Annexin-V staining and TUNEL assay were used to detect alterations in cell cycle and apoptosis after 72 h of treatment. The TTFields/IN-3 combination decreased cell proliferation after 72 h compared to either treatment alone (-78.6% vs. TTFields, P = 0.0337; -52.6% vs. IN-3, P = 0.0205), and reduced the number of viable cells (62% less than seeded). There was a significant cell cycle shift from G1 to G2/M phase (P < 0.0001). The apoptotic rate increased to 44% (TTFields 14%, P = 0.0002; IN-3 4%, P < 0.0001). Cell growth recovered 24 h after EOT with TTFields and IN-3 alone, but the combination led to further decrease by 92% at 72 h EOT if IN-3 treatment was continued (P = 0.0288). The combination of TTFields and SAC inhibition led to earlier and prolonged effects that significantly augmented the efficacy of TTFields and highlights a potential new targeted multimodal treatment for GBM.

Highlighting the need for reliable clinical trials in glioblastoma

INTRODUCTION

Several recent phase III studies have attempted to improve the dismal survival seen in glioblastoma patients, with disappointing results despite prior promising phase II data. Areas covered: A literature review of prior phase II and phase III studied in glioblastoma was performed to help identify possible areas of concern. Numerous issues in previous phase II trials for glioblastoma were found that may have contributed to these discouraging outcomes and discordant results. Expert commentary: These concerns include the improper selection of therapeutics warranting investigation in a phase III trial, suboptimal design of phase II studies (often lacking a control arm), absence of molecular data, the use of imaging criteria as a surrogate endpoint, and a lack of pharmacodynamic testing. Hopefully, by recognizing prior phase II trial limitations that contributed to failed phase III trials, we can adapt quickly to improve our ability to accurately discover survival-prolonging treatments for glioblastoma patients.

Recurrent Glioblastoma Treated with Recombinant Poliovirus

BACKGROUND

The prognosis of patients with recurrent World Health Organization (WHO) grade IV malignant glioma is dismal, and there is currently no effective therapy. We conducted a dose-finding and toxicity study in this population of patients, evaluating convection-enhanced, intratumoral delivery of the recombinant nonpathogenic polio-rhinovirus chimera (PVSRIPO). PVSRIPO recognizes the poliovirus receptor CD155, which is widely expressed in neoplastic cells of solid tumors and in major components of the tumor microenvironment.

METHODS

We enrolled consecutive adult patients who had recurrent supratentorial WHO grade IV malignant glioma, confirmed on histopathological testing, with measurable disease (contrast-enhancing tumor of ≥1 cm and ≤5.5 cm in the greatest dimension). The study evaluated seven doses, ranging between 10⁷ and 10¹⁰ 50% tissue-culture infectious doses (TCID₅₀), first in a dose-escalation phase and then in a dose-expansion phase.

RESULTS

From May 2012 through May 2017, a total of 61 patients were enrolled and received a dose of PVSRIPO. Dose level -1 (5.0×10⁷ TCID₅₀) was identified as the phase 2 dose. One dose-limiting toxic effect was observed; a patient in whom dose level 5 (10¹⁰ TCID₅₀) was administered had a grade 4 intracranial hemorrhage immediately after the catheter was removed. To mitigate locoregional inflammation of the infused tumor with prolonged glucocorticoid use, dose level 5 was deescalated to reach the phase 2 dose. In the dose-expansion phase, 19% of the patients had a PVSRIPO-related adverse event of grade 3 or higher. Overall survival among the patients who received PVSRIPO reached a plateau of 21% (95% confidence interval, 11 to 33) at 24 months that was sustained at 36 months.

CONCLUSIONS

Intratumoral infusion of PVSRIPO in patients with recurrent WHO grade IV malignant glioma confirmed the absence of neurovirulent potential. The survival rate among patients who received PVSRIPO immunotherapy was higher at 24 and 36 months than the rate among historical controls. (Funded by the Brain Tumor Research Charity and others; ClinicalTrials.gov number, NCT01491893 .).

Early platelet variation during concomitant chemo-radiotherapy predicts adjuvant temozolomide-induced thrombocytopenia in newly diagnosed glioblastoma patients

PURPOSE

Temozolomide (TMZ) is known to induce thrombocytopenia but no early predictive test has yet been clearly established. The aim of the study was to retrospectively identify and validate a threshold of early platelet variation predicting TMZ-induced thrombocytopenia during the TMZ phase in patients treated according to the Stupp protocol for glioblastoma.

METHODS

A training set was used to analyze variations in platelet count occurring from the first week (W1) to week 6 (W6) during radiotherapy. Our aim was to identify the most relevant platelet decrease associated with TMZ-induced thrombocytopenia ≤ 100 G/L at day 28 during the TMZ phase. The performance of the threshold was confirmed in an independent validation set.

RESULTS

Overall, 147 patients were included, 85 and 62 in the training and validation sets, respectively. Twenty-seven patients (18%) experienced at least one TMZ-induced thrombocytopenia in the TMZ phase. A platelet decrease at W6 ≥ 35% (∆W6 ≥ 35%) was identified as the best predictive variation with an AUC of 0.83, a sensitivity of 65%, and a specificity of 96%. In the validation set, ∆W6 ≥ 35% platelet variation was identified as an independent marker of TMZ-induced thrombocytopenia during the TMZ phase (OR 15.23 (95% CI 3.5-107.5)) corresponding to sensitivity of 77% (66-87%), specificity of 73% (62-84%), a positive predictive value of 42% (29-54%), and a negative predictive value of 92% (86-99%).

CONCLUSION

Platelet decrease at W6 ≥ 35% during the RT-TMZ phase is an early and simple predictive marker of clinically relevant TMZ-induced thrombocytopenia during TMZ maintenance.

[Early postsurgical temozolomide treatment in newly diagnosed bad prognosis glioblastoma patients: Feasibility study]

INTRODUCTION

Despite the combined adjuvant treatment of radiotherapy plus chemotherapy with temozolomide (TMZ) followed by 6 cycles of temozolomide after surgery, the prognosis of patients with glioblastoma remains poor. We conducted a monocentric prospective study to explore the tolerance and potential efficacy of an early temozolomide cycle after surgery.

METHOD

Patients with newly diagnosed glioblastoma (unmutated IDH1) and of poor prognosis (age>50 years, biopsy or partial resection or unmethylated MGMT promoter) were prospectively included from June 2014 to 2017. They all received a cycle of 5 days of temozolomide between surgery and the combined adjuvant treatment.

RESULTS

Twelve patients of median age 64.5 years (45-73) were included in the study. The median doses of temozolomide administered were respectively 265mg (225-300) for the early cycle; 130mg (110-150) for the concomitant treatment and 310mg (225-400) for the adjuvant one. Side effects during treatment were grade III lymphopenia, grade III neutropenia, fatigue and nausea/vomiting respectively in 4, 1, 7 and 5 patients. Progression-free survival and overall survival were respectively 90% and 91.7% at 6 months; 58.3 and 71.3% at 12 months; 31.1 and 71.3% at 18 months.

CONCLUSION

Early postsurgical temozolomide treatment prior to standard adjuvant therapy for poor prognosis glioblastoma patients in our small prospective series presents toxicity and survival similar to those published in the literature for the general population of glioblastoma. These encouraging results should be confirmed by a multicentric study comparing this regiment with the standard treatment.

Precision Neuro-oncology: the Role of Genomic Testing in the Management of Adult and Pediatric Gliomas

OPINION STATEMENT

In recent years, large-scale genomic studies have expanded our knowledge regarding genomic drivers in tumors of the central nervous system. While histopathologic analysis of brain tumors remains the primary method for tumor classification, the clinical utility of molecular and genomic testing to support and/or complement tumor classification continues to expand. This approach enhances diagnostic accuracy and provides clinicians with objective data to facilitate discussions regarding prognosis and treatment decisions, including selection of clinical trials. Ensuring accurate diagnoses is fundamental to the management of brain tumor patients. However, given the morphologic overlap among primary brain tumors, genomic data can be used to help distinguish tumor lineage. In its clearest form, we have embraced the concept of an integrated diagnosis, which combines traditional histopathology findings with molecular and genomic data. Patient prognosis varies significantly based on a tumor's genomic profile. For neuro-oncology patients, outcome studies linking diagnoses with genomic profiles show significant differences based on tumor biomarkers such as IDH1/2, H3F3A, BRAF, and CDKN2A and TERT status. Therefore, easy access to reliable genomic data is important in understanding a patient's disease and developing a clinical strategy wherein targeted molecular or immune therapies can be incorporated into the discussion.

Amino Acid PET Imaging of the Early Metabolic Response During Tumor-Treating Fields (TTFields) Therapy in Recurrent Glioblastoma

Tumor-treating fields (TTFields) therapy is a relatively new treatment approach for malignant gliomas. We evaluated if amino acid PET can detect an objective metabolic response to TTFields therapy in recurrent glioblastomas. PET scanning with alpha[C-11]-methyl-L-tryptophan (AMT) before and 2 to 3 months after the start of TTFields treatment showed an interval decrease of tryptophan uptake in the whole tumor (2 patients) or in a portion of the tumor (1 patient). These data demonstrate that TTFields therapy can induce an early metabolic response in recurrent glioblastoma, and this treatment response can be detected by amino acid PET.

Radiotherapy of Glioblastoma 15 Years after the Landmark Stupp's Trial: More Controversies than Standards?

Background

The current standard of care of glioblastoma, the most common primary brain tumor in adults, has remained unchanged for over a decade. Nevertheless, some improvements in patient outcomes have occurred as a consequence of modern surgery, improved radiotherapy and up-to-date management of toxicity. Patients from control arms (receiving standard concurrent chemoradiotherapy and adjuvant chemotherapy with temozolomide) of recent clinical trials achieve better outcomes compared to the median survival of 14.6 months reported in Stupp’s landmark clinical trial in 2005. The approach to radiotherapy that emerged from Stupp’s trial, which continues to be a basis for the current standard of care, is no longer applicable and there is a need to develop updated guidelines for radiotherapy within the daily clinical practice that address or at least acknowledge existing controversies in the planning of radiotherapy.

The goal of this review is to provoke critical thinking about potentially controversial aspects in the radiotherapy of glioblastoma, including among others the issue of target definitions, simultaneously integrated boost technique, and hippocampal sparing.

Conclusions

In conjunction with new treatment approaches such as tumor-treating fields (TTF) and immunotherapy, the role of adjuvant radiotherapy will be further defined. The personalized approach in daily radiotherapy practice is enabled with modern radiotherapy systems.

First results on survival from a large Phase 3 clinical trial of an autologous dendritic cell vaccine in newly diagnosed glioblastoma

Background

Standard therapy for glioblastoma includes surgery, radiotherapy, and temozolomide. This Phase 3 trial evaluates the addition of an autologous tumor lysate-pulsed dendritic cell vaccine (DCVax^®-L) to standard therapy for newly diagnosed glioblastoma.

Methods

After surgery and chemoradiotherapy, patients were randomized (2:1) to receive temozolomide plus DCVax-L (n = 232) or temozolomide and placebo (n = 99). Following recurrence, all patients were allowed to receive DCVax-L, without unblinding. The primary endpoint was progression free survival (PFS); the secondary endpoint was overall survival (OS).

Results

For the intent-to-treat (ITT) population (n = 331), median OS (mOS) was 23.1 months from surgery. Because of the cross-over trial design, nearly 90% of the ITT population received DCVax-L. For patients with methylated MGMT (n = 131), mOS was 34.7 months from surgery, with a 3-year survival of 46.4%. As of this analysis, 223 patients are ≥ 30 months past their surgery date; 67 of these (30.0%) have lived ≥ 30 months and have a Kaplan-Meier (KM)-derived mOS of 46.5 months. 182 patients are ≥ 36 months past surgery; 44 of these (24.2%) have lived ≥ 36 months and have a KM-derived mOS of 88.2 months. A population of extended survivors (n = 100) with mOS of 40.5 months, not explained by known prognostic factors, will be analyzed further. Only 2.1% of ITT patients (n = 7) had a grade 3 or 4 adverse event that was deemed at least possibly related to the vaccine. Overall adverse events with DCVax were comparable to standard therapy alone.

Conclusions

Addition of DCVax-L to standard therapy is feasible and safe in glioblastoma patients, and may extend survival.

Trial registration Funded by Northwest Biotherapeutics; Clinicaltrials.gov number: NCT00045968; https://clinicaltrials.gov/ct2/show/NCT00045968?term=NCT00045968&rank=1; initially registered 19 September 2002

Drug delivery challenges and future of chemotherapeutic nanomedicine for glioblastoma treatment

Glioblastoma (GBM) is one of the most aggressive and deadliest central nervous system tumors, and the current standard treatment is surgery followed by radiotherapy with concurrent chemotherapy. Nevertheless, the survival period is notably low. Although ample research has been performed to develop an effective therapeutic strategy for treating GBM, the success of extending patients' survival period and quality of life is limited. This review focuses on the strategies developed to address the challenges associated with drug delivery in GBM, particularly nanomedicine. The first part describes major obstacles to the development of effective GBM treatment strategies. The second part focuses on the conventional chemotherapeutic nanomedicine strategies, their limitations and the novel and advanced strategies of nanomedicine, which could be promising for GBM treatment. We also highlighted the prominence of nanomedicine clinical translation. The near future looks bright following the beginning of clinical translation of nanochemotherapy for GBM.

Radiation Oncology in the 21st Century: Prospective Randomized Trials That Changed Practice… or Didn't!

In a two-part article published in 2009, we discussed the limitations of conventional radiation therapy, the challenges of studying new technologies in radiation oncology, and summarized the state-of-the science for various malignancies (1, 2). Here, we summarize some of the most important prospective, randomized trials that during the intervening years have attempted to improve the tumor control and/or decrease the adverse effects of radiation therapy. For consistency, we have focused here on the null and alternate hypotheses as articulated by the investigators at the onset of each trial, since the outcome of the investigational treatment should be considered clinically significant only if the null hypothesis was rejected. The readers (and patients) are of course free to make their own judgments about the clinical significance of the results when the null hypothesis was not rejected.

A Cytotoxic Three-Dimensional-Spheroid, High-Throughput Assay Using Patient-Derived Glioma Stem Cells

Glioblastoma (GBM) is the most aggressive primary brain cancer with an average survival time after diagnosis of only 12-14 months, with few (<5%) long-term survivors. A growing body of work suggests that GBMs contain a small population of glioma stem cells (GSCs) that are thought to be major contributors to treatment resistance and disease relapse. Identifying compounds that modulate GSC proliferation would provide highly valuable molecular probes of GSC-directed signaling. However, targeting GSCs pharmacologically has been challenging. Patient-derived GSCs can be cultured as neurospheres, and in vivo these cells functionally recapitulate the heterogeneity of the original tumor. Using patient-derived GSC-enriched cultures, we have developed a 1536-well spheroid-based proliferation assay and completed a pilot screen, testing ~3300 compounds comprising approved drugs. This cytotoxic and automation-friendly assay yielded a signal-to-background (S/B) ratio of 161.3 ± 7.5 and Z' of 0.77 ± 0.02, demonstrating its robustness. Importantly, compounds were identified with anti-GSC activity, demonstrating the applicability of this assay for large-scale high-throughput screening (HTS).

Of Fields and Phantoms : The Importance of Virtual Humans in Optimizing Cancer Treatment with Tumor Treating Fields

Cancer represents a compilation of diseases characterized by rapidly dividing, invasive cells. Worldwide data indicate that over 14 million new cancers were diagnosed in 2012, with a projected increase of more than 19 million diagnosed cases by 2025 [1]. Survival rates for some cancers have increased dramatically, but there are still cancer types for which the prognosis is poor and few treatments exist. Thus, there is a growing need for new therapies targeting these difficult-to-treat cancers.

Repurposing drugs for glioblastoma: From bench to bedside

Glioblastoma multiforme is the most common, aggressive and lethal type of brain tumor. It is a stage IV cancer disease with a poor prognosis, as the current therapeutic options (surgery, radiotherapy and chemotherapy) are not able to eradicate tumor cells. The approach to treat glioblastoma has not suffered major changes over the last decade and temozolomide (TMZ) remains the mainstay for chemotherapy. However, resistance mechanisms to TMZ and other chemotherapeutic agents are becoming more frequent. The lack of effective options is a reality that may be counterbalanced by repositioning known and commonly used drugs for other diseases. This approach takes into consideration the available pharmacokinetic, pharmacodynamic, toxicity and safety data, and allows a much faster and less expensive drug and product development process. In this review, an extensive literature search is conducted aiming to list drugs with repurposing usage, based on their preferential damage in glioblastoma cells through various mechanisms. Some of these drugs have already entered clinical trials, exhibiting favorable outcomes, which sparks their potential application in glioblastoma treatment.

EGFRvIII-Stat5 Signaling Enhances Glioblastoma Cell Migration and Survival

Glioblastoma multiforme (GBM) is the most common brain malignancies in adults. Most GBM patients succumb to the disease less than 1 year after diagnosis due to the highly invasive nature of the tumor, which prevents complete surgical resection and gives rise to tumor recurrence. The invasive phenotype also confers radioresistant and chemoresistant properties to the tumor cells; therefore, there is a critical need to develop new therapeutics that target drivers of GBM invasion. Amplification of EGFR is observed in over 50% of GBM tumors, of which half concurrently overexpress the variant EGFRvIII, and expression of both receptors confers a worse prognosis. EGFR and EGFRvIII cooperate to promote tumor progression and invasion, in part, through activation of the Stat signaling pathway. Here, it is reported that EGFRvIII activates Stat5 and GBM invasion by inducing the expression of a previously established mediator of glioma cell invasion and survival: fibroblast growth factor-inducible 14 (Fn14). EGFRvIII-mediated induction of Fn14 expression is Stat5 dependent and requires activation of Src, whereas EGFR regulation of Fn14 is dependent upon Src-MEK/ERK-Stat3 activation. Notably, treatment of EGFRvIII-expressing GBM cells with the FDA-approved Stat5 inhibitor pimozide blocked Stat5 phosphorylation, Fn14 expression, and cell migration and survival. Because EGFR inhibitors display limited therapeutic efficacy in GBM patients, the EGFRvIII-Stat5-Fn14 signaling pathway represents a node of vulnerability in the invasive GBM cell populations.Implications: Targeting critical effectors in the EGFRvIII-Stat5-Fn14 pathway may limit GBM tumor dispersion, mitigate therapeutic resistance, and increase survival. Mol Cancer Res; 16(7); 1185-95. ©2018 AACR.

Understanding patterns of brain metastasis in breast cancer and designing rational therapeutic strategies

One of the most feared sequelae after a diagnosis of advanced breast cancer is development of metastases to the brain as this diagnosis can affect physical function, independence, relationships, quality of life, personality, and ultimately one's sense of self. The propensity to develop breast cancer brain metastases (BCBMs) varies by subtype, occurring in up to one half of those with triple negative breast cancer (TNBC), approximately a third of HER+ breast cancers and 14% in hormone positive disease. Median survival after BCBM diagnosis can be as short as 5 months in TNBC and 10-18 months in the other subtypes. Here, we review the biology of BCBMs and how it informs the rational design of new therapeutic approaches and agents. We discuss application of novel targeted and immunotherapies by breast cancer subtype. It is noteworthy that there are no U.S. Food and Drug Administration (FDA)-approved treatments specifically for BCBMs currently. Nevertheless, there are legitimate grounds for hope as patients with BCBMs are now being included in clinical trials of systemic therapies and a better understanding of the biology and genetic underpinning of BCBMs is driving an increased range of options for patients.

BRAF inhibition with concomitant tumor treating fields for a multiply progressive pleomorphic xanthoastrocytoma

Pleomorphic xanthoastrocytomas can be very resistant to treatment if they progress after standard therapy with surgery and radiation. We present the case of a patient with a multiply recurrent pleomorphic xanthoastrocytoma which demonstrated a sustained partial response to a combination regimen of the BRAF inhibitor vemurafenib and tumor treating fields. The regimen proved tolerable and efficacious in this case.

Overview on current treatment standards in high-grade gliomas

High-grade gliomas (HGGs) are the most common primary tumors of the central nervous system, which include anaplastic gliomas (grade III) and glioblastomas (GBM, grade IV). Surgery is the mainstay of treatment in HGGs in order to achieve a histological and molecular characterization, as well as relieve neurological symptoms and improve seizure control. Combinations of some molecular factors, such as IDH 1-2 mutations, 1p/19q codeletion and MGMT methylation status, allow to classify different subtypes of gliomas and identify patients with different outcome. The SOC in HGGs consists in a combination of radiotherapy and chemotherapy with alkylating agents. Despite this therapeutic approach, tumor recurrence occurs in HGGs, and new surgical debulking, reirradiation or second-line chemotherapy are needed. Considering the poor results in terms of survival, several clinical trials have explored the efficacy and tolerability of antiangiogenic agents, targeted therapies against epidermal growth factor receptor (EGFR) and different immunotherapeutic approaches in recurrent and newly-diagnosed GBM, including immune checkpoint inhibitors (ICIs), and cell- or peptide-based vaccination with unsatisfactory results in term of disease control. In this review we describe the major updates in molecular biology of HGGs according to 2016 WHO Classification, the current management in newly-diagnosed and recurrent GBM and grade III gliomas, and the results of the most relevant clinical trials on targeted agents and immunotherapy.

C-type natriuretic peptide-modified lipid vesicles: fabrication and use for the treatment of brain glioma

Chemotherapy of brain glioma faces a major obstacle owing to the inability of drug transport across the blood-brain barrier (BBB). Besides, neovasculatures in brain glioma site result in a rapid infiltration, making complete surgical removal virtually impossible. Herein, we reported a novel kind of C-type natriuretic peptide (CNP) modified vinorelbine lipid vesicles for transferring drug across the BBB, and for treating brain glioma along with disrupting neovasculatures. The studies were performed on brain glioma U87-MG cells in vitro and on glioma-bearing nude mice in vivo. The results showed that the CNP-modified vinorelbine lipid vesicles could transport vinorelbine across the BBB, kill the brain glioma, and destroy neovasculatures effectively. The above mechanisms could be associated with the following aspects, namely, long circulation in the blood; drug transport across the BBB via natriuretic peptide receptor B (NPRB)-mediated transcytosis; elimination of brain glioma cells and disruption of neovasculatures by targeting uptake and cytotoxic injury. Besides, CNP-modified vinorelbine lipid vesicles could induce apoptosis of the glioma cells. The mechanisms could be related to the activations of caspase 8, caspase 3, p53, and reactive oxygen species (ROS), and inhibition of survivin. Hence, CNP-modified lipid vesicles could be used as a carrier material for treating brain glioma and disabling glioma neovasculatures.

Interim Results of a Phase II Study of Hypofractionated Radiotherapy with Concurrent Temozolomide Followed by Adjuvant Temozolomide in Patients over 70 Years Old with Newly Diagnosed Glioblastoma

OBJECTIVE

In this phase II study, we investigate clinical outcomes and tolerability of hypofractionated radiotherapy (HRT) combined with temozolomide (TMZ) to treat elderly patients with glioblastoma (GBM).

METHODS

Patients 70 years of age or older with newly diagnosed GBM received HRT to a dose of 34 Gy given in ten fractions over 2 weeks, delivered with concurrent and adjuvant TMZ.

RESULTS

In this interim analysis, ten patients were enrolled on trial from 12/1/2015 to 4/5/2017. With a median follow-up of 9 months (range 3-12 months), median progression-free survival (PFS) was 6 months. The median overall survival (OS) has not been reached. Estimated 1-year OS and PFS rates were 53.3 and 44.4%, respectively. All patients completed the full course of RT, with no patients developing grade 3 or higher adverse events from treatment.

CONCLUSIONS

The preliminary results of our phase II trial suggest HRT delivered over 2 weeks with concurrent and adjuvant TMZ is well tolerated in elderly patients with GBM without compromising clinical outcomes.

Multicenter Phase IB Trial of Carboxyamidotriazole Orotate and Temozolomide for Recurrent and Newly Diagnosed Glioblastoma and Other Anaplastic Gliomas

Purpose Carboxyamidotriazole orotate (CTO) is a novel oral inhibitor of non-voltage-dependent calcium channels with modulatory effects in multiple cell-signaling pathways and synergistic effects with temozolomide (TMZ) in glioblastoma (GBM) models. We conducted a phase IB study combining CTO with two standard TMZ schedules in GBM. Methods In cohort 1, patients with recurrent anaplastic gliomas or GBM received escalating doses of CTO (219 to 812.5 mg/m² once daily or 600 mg fixed once-daily dose) combined with TMZ (150 mg/m² 5 days during each 28-day cycle). In cohort 2, patients with newly diagnosed GBM received escalating doses of CTO (219 to 481 mg/m²/d once daily) with radiotherapy and TMZ 75 mg/m²/d, followed by TMZ 150 mg to 200 mg/m² 5 days during each 28-day cycle. Results Forty-seven patients were enrolled. Treatment was well tolerated; toxicities included fatigue, constipation, nausea, and hypophosphatemia. Pharmacokinetics showed that CTO did not alter TMZ levels; therapeutic concentrations were achieved in tumor and brain. No dose-limiting toxicities were observed; the recommended phase II dose was 600 mg/d flat dose. Signals of activity in cohort 1 (n = 27) included partial (n = 6) and complete (n = 1) response, including in O⁶-methylguanine-DNA methyltransferase unmethylated and bevacizumab-refractory tumors. In cohort 2 (n = 15), median progression-free survival was 15 months and median overall survival was not reached (median follow-up, 28 months; 2-year overall survival, 62%). Gene sequencing disclosed a high rate of responses among EGFR-amplified tumors ( P = .005), with mechanisms of acquired resistance possibly involving mutations in mismatch-repair genes and/or downstream components TSC2, NF1, NF2, PTEN, and PIK3CA. Conclusion CTO can be combined safely with TMZ or chemoradiation in GBM and anaplastic gliomas, displaying favorable brain penetration and promising signals of activity in this difficult-to-treat population.

Epstein-Barr Virus in Gliomas: Cause, Association, or Artifact?

Gliomas are the most common malignant brain tumors and account for around 60% of all primary central nervous system cancers. Glioblastoma multiforme (GBM) is a grade IV glioma associated with a poor outcome despite recent advances in chemotherapy. The etiology of gliomas is unknown, but neurotropic viruses including the Epstein–Barr virus (EBV) that is transmitted via salivary and genital fluids have been implicated recently. EBV is a member of the gamma herpes simplex family of DNA viruses that is known to cause infectious mononucleosis (glandular fever) and is strongly linked with the oncogenesis of several cancers, including B-cell lymphomas, nasopharyngeal, and gastric carcinomas. The fact that EBV is thought to be the causative agent for primary central nervous system (CNS) lymphomas in immune-deficient patients has led to its investigations in other brain tumors including gliomas. Here, we provide a review of the clinical literature pertaining to EBV in gliomas and discuss the possibilities of this virus being simply associative, causative, or even an experimental artifact. We searched the PubMed/MEDLINE databases using the following key words such as: glioma(s), glioblastoma multiforme, brain tumors/cancers, EBV, and neurotropic viruses. Our literature analysis indicates conflicting results on the presence and role of EBV in gliomas. Further comprehensive studies are needed to fully implicate EBV in gliomagenesis and oncomodulation. Understanding the role of EBV and other oncoviruses in the etiology of gliomas, would likely open up new avenues for the treatment and management of these, often fatal, CNS tumors.

Ultrasound-Activated Piezoelectric Nanoparticles Inhibit Proliferation of Breast Cancer Cells

A nanotechnology-based approach for the inhibition of breast cancer cell proliferation is proposed. The innovative solution consists in a platform based on biocompatible piezoelectric nanoparticles able to target and remotely stimulate HER2-positive breast cancer cells. The anti-proliferative effects of the ultrasound-driven piezoelectric nanoparticle-assisted stimulation significantly reduced the proliferation by inducing the cell cycle arrest. Similarly to a low-intensity alternating electric field, chronic piezoelectric stimulation resulted able to inhibit cancer cell proliferation by upregulating the expression of the gene encoding Kir3.2 inward rectifier potassium channels, by interfering on Ca²⁺ homeostasis, and by affecting the organization of mitotic spindles during mitosis. The proposed platform, even if specific for HER2-positive cells, shows huge potential and versatility for the treatment of different type of cancers.

Proseek single-plex protein assay kit system to detect sAxl and Gas6 in serological material of brain tumor patients

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Establishment of an alternative method beside routinely used ELISA to measure levels of sAxl and Gas6 in serological material of HGG patients is proposed.

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Both antibodies are established with the powerful combination of protein detection and PCR amplification using the Proseek Single-Plex Assay.

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This tool quantifies single proteins in solution with a maximum of sensitivity and specificity to visualize low levels of proteins in just 1 μl blood sample within one day.

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The receptor tyrosine kinase (RTK) Axl and its ligand Gas6 are critically involved in the pathogenesis of high-grade glioma (HGG). Both proteins were found to be overexpressed e.g. in tumor cells, mediating cell proliferation and migration as well as tumor angiogenesis and neuroinflammation. The extracellular domain of Axl (sAxl) and Gas6 were found in the peri-tumoral edema and blood of animals as well as in human glioma tissue. Therefore, we monitored the level of sAxl and Gas6 in human blood samples. To increase the sensitivity of protein detection beyond commonly used standard methods we preliminary tested the innovative Proseek Single-Plex Protein Assay Kit System from Olink Bioscience together with new antibodies against the soluble RTK sAxl and its ligand Gas6. We conclude that the Proseek method is a highly sensitive and fast procedure that can be used as a possible powerful tool compared to routinely used ELISA-methods.

Characteristics and survival outcomes associated with the lack of radiation in the treatment of glioblastoma

Radiation increases survival in glioblastoma (GBM); however, 30% do not receive this treatment. We sought to identify characteristics associated with not receiving radiation and the impact on outcomes. We analyzed the Surveillance, Epidemiology, and End Results program (SEER) 18 registries 2000-2013 research database on 30,479 GBM cases that were aged 20 years and older. In total, 21,179 received radiation as first course of therapy, while 8218 did not with 5178 (63%) being 65 years and older. Early decisions on surgery often predicted radiation therapy with 61% having only a biopsy or no surgery at diagnosis. Radiation use as upfront therapy has slowly increased over time at a rate of 0.4% per year; still 25% did not receive radiation in 2013. Cases treated with radiation were more likely to be younger, underwent surgery, lived in a metropolitan area, had higher socioeconomic status, and were in a couple-based relationship. An increased survival in GBM was associated with the use of upfront radiation along with younger age, being of race other than white, undergoing surgery, and a more recent diagnosis. Not receiving radiation therapy adversely affects survival. A trend toward an increased use of radiation was observed although many young adults still do not receive this treatment. Decreased usage of radiation in the elderly and in biopsy-only surgeries was anticipated, but race, gender, and poverty were also statistically significant. Clinicians should be aware of this underutilization, and an increased usage of radiation should improve outcomes for glioblastoma.

A single dose of peripherally infused EGFRvIII-directed CAR T cells mediates antigen loss and induces adaptive resistance in patients with recurrent glioblastoma

We conducted a first-in-human study of intravenous delivery of a single dose of autologous T cells redirected to the epidermal growth factor receptor variant III (EGFRvIII) mutation by a chimeric antigen receptor (CAR). We report our findings on the first 10 recurrent glioblastoma (GBM) patients treated. We found that manufacturing and infusion of CAR-modified T cell (CART)-EGFRvIII cells are feasible and safe, without evidence of off-tumor toxicity or cytokine release syndrome. One patient has had residual stable disease for over 18 months of follow-up. All patients demonstrated detectable transient expansion of CART-EGFRvIII cells in peripheral blood. Seven patients had post-CART-EGFRvIII surgical intervention, which allowed for tissue-specific analysis of CART-EGFRvIII trafficking to the tumor, phenotyping of tumor-infiltrating T cells and the tumor microenvironment in situ, and analysis of post-therapy EGFRvIII target antigen expression. Imaging findings after CART immunotherapy were complex to interpret, further reinforcing the need for pathologic sampling in infused patients. We found trafficking of CART-EGFRvIII cells to regions of active GBM, with antigen decrease in five of these seven patients. In situ evaluation of the tumor environment demonstrated increased and robust expression of inhibitory molecules and infiltration by regulatory T cells after CART-EGFRvIII infusion, compared to pre-CART-EGFRvIII infusion tumor specimens. Our initial experience with CAR T cells in recurrent GBM suggests that although intravenous infusion results in on-target activity in the brain, overcoming the adaptive changes in the local tumor microenvironment and addressing the antigen heterogeneity may improve the efficacy of EGFRvIII-directed strategies in GBM.

Differential Effects of Estrogen Receptor β Isoforms on Glioblastoma Progression

The estrogen receptor β (ERβ) functions as a tumor suppressor in glioblastoma (GBM) cells. However, the in vivo significance of endogenous ERβ and the roles of its isoforms in GBM are incompletely understood. Using ERβ isoform-specific PCR screening, we found that GBM cells predominantly express ERβ1 and ERβ5, along with low levels of ERβ2 and ERβ4. We observed greater ERβ5 expression in higher grades of glioma than in lower grades. In CRISPR-based ERβ knockout (KO) cells and ERβ KO cells uniquely expressing ERβ1 or ERβ5 only, ERβ1 significantly reduced proliferation. Compared with parental GBM cells, ERβ KO cells exhibited high migratory and invasive potentials, and reexpression of ERβ1 resulted in the reduction of this phenotype. Interestingly, ERβ5 expression increased foci formation and anchorage-independent growth of NIH3T3 cells and increased motile structure formation, including filopodia and ruffles in GBM cells. Only ERβ1-expressing tumors resulted in longer mouse survival. RNA-Seq analysis revealed unique pathways modulated by ERβ1 and ERβ5. Compared with ERβ KO cells, ERβ1 cells exhibited lower activation of mTOR signaling molecules, including p-mTOR, p-S6K, and p-S6, and ERβ5-expressing cells had enhanced mTOR downstream signaling. Unique proteins including several that function as regulators of mTOR, immunomodulatory, and apoptosis pathways bound to ERβ1 and ERβ5 isoforms. Our work confirms the tumor-suppressive potential of ERβ1 and reveals the acquired oncogenic ability of ERβ5 in GBM cells. ERβ isoform status and their unique interactions with oncogenic pathways may have important implications in GBM progression.Significance: These findings suggest that only ERβ isoform 1 has tumor suppressor function in GBM and that ERβ isoform switching contributes to GBM progression. Cancer Res; 78(12); 3176-89. ©2018 AACR.

New Hypofractionation Radiation Strategies for Glioblastoma

PURPOSE OF REVIEW

Glioblastoma (GBM) is the most common and lethal primary brain tumor in adults, with a median survival of less than 2 years despite the standard of care treatment of 6 weeks of chemoradiotherapy. We review the data investigating hypofractionated radiotherapy (HFRT) in the treatment of newly diagnosed GBM.

RECENT FINDINGS

Investigators have explored alternative radiotherapy strategies that shorten treatment duration with the goal of similar or improved survival while minimizing toxicity. HFRT over 1-3 weeks is already a standard of care for patients with advanced age or poor performance status. For young patients with good performance status, HFRT holds the promise of radiobiologically escalating the dose and potentially improving local control while maintaining quality of life. Through the use of shorter radiotherapy fractionation regimens coupled with novel systemic agents, improved outcomes for patients with GBM may be achieved.

Tumor Treating Fields in Neuro-Oncological Practice

Electric fields are known to produce biological effects. Depending on specific frequency, they can stimulate healing, directly damage tissues, or produce anti-mitotic activity. Frequencies of 100-300 KHz have been shown to disrupt mitosis and lead to cellular death. Growth of cancer cell lines, both in vitro and in vivo, was shown to be inhibited by application of the electric fields. In the clinical setting, electric fields are available for treatment of brain tumors, specifically glioblastoma (GBM), through a portable device producing so-called tumor treating fields (TTF). Clinical trials conducted in patients with recurrent and newly diagnosed GBM indicated that this novel treatment modality is active and associated with minimal toxicity. This manuscript will review the available evidence supporting the use of TTF in neuro-oncologic practice.

Acceptance and compliance of TTFields treatment among high grade glioma patients

BACKGROUND

Tumor treating fields (TTFields) significantly prolong both progression-free and overall survival in patients with newly diagnosed glioblastoma (GBM). TTFields are delivered to the brain tumor via skin transducer arrays and should be applied for a minimum of 18 h per day (≥ 75% compliance). This may cause limited acceptance by patients because of obstacles in daily routine. So far, there are limited data on factors influencing therapy acceptance and compliance.

METHODS

In this retrospective study, fourty-one patients with primary GBM or recurrent high grade glioma (rHGG) have been treated with TTFields in our department. Compliance reports were generated at the monthly routine check of the device. We investigated demographic data, stage of disease and therapy duration in regard to treatment compliance.

RESULTS

Thirty percent of patients with primary diagnosis of GBM were informed about TTFields. Acceptance rate among these patients was 36%. In this study, TTFields were prescribed in newly diagnosed GBM patients (57%) and in rHGG. Mean treatment compliance was 87% in the total population independent of age, sex and stage of disease. Compliance was not negatively correlated with time on treatment.

CONCLUSION

TTFields are effective in newly diagnosed GBM, therefore acceptance and compliance is important for GBM treatment. We experienced moderate acceptance rate for TTFields, which is influenced by factors such as social support, comorbidities and independence in daily life. Overall therapy compliance lies above 75% and is not influenced by age, sex, stage of disease or duration of therapy. Improved patient consultation strategies will increase acceptance and compliance for better outcome.

Molecular Targeting of Acid Ceramidase in Glioblastoma: A Review of Its Role, Potential Treatment, and Challenges

Glioblastoma is the most common, malignant primary tumor of the central nervous system. The average prognosis for life expectancy after diagnosis, with the triad of surgery, chemotherapy, and radiation therapy, is less than 1.5 years. Chemotherapy treatment is mostly limited to temozolomide. In this paper, the authors review an emerging, novel drug called acid ceramidase, which targets glioblastoma. Its role in cancer treatment in general, and more specifically, in the treatment of glioblastoma, are discussed. In addition, the authors provide insights on acid ceramidase as a potential druggable target for glioblastoma.

Reoperation for Recurrent Glioblastoma Multiforme

The role of reoperation for glioblastoma multiforme (GBM) recurrence is currently unknown. However, multiple studies have indicated that survival and quality of life are improved with a repeat operation at the time of disease recurrence. Prognosis is likely interdependent on several factors, including age, functional status, initial resection status, disease location, and surgical efficacy. However, there are significant data indicating no survival benefit for reoperation. This comprehensive literature review considering the controversial question of whether to operate for progressive or recurrent GBM seeks to evaluate the current available evidence and report on its conclusions.

Pathogenic role for macrophage migration inhibitory factor in glioblastoma and its targeting with specific inhibitors as novel tailored therapeutic approach

Macrophage Migration Inhibitory Factor (MIF) is a pro-inflammatory cytokine expressed by a variety of cell types. Although MIF has been primarily studied for its role in the pathogenesis of autoimmune diseases, it has also been shown to promote tumorigenesis and it is over expressed in various malignant tumors. MIF is able to induce angiogenesis, cell cycle progression, and to block apoptosis. As tailored therapeutic approaches for the inhibition of endogenous MIF are being developed, it is important to evaluate the role of MIF in individual neoplastic conditions that may benefit from specific MIF inhibitors. Along with this line, in this paper, we have reviewed the evidence of the involvement of MIF in the etiopathogenesis and progression of glioblastoma and the preclinical data suggesting the possible use of specific MIF inhibition as a potential novel therapeutic strategy for brain tumors.

Antitumoral effects of the alkynylphosphonate analogue of calcitriol EM1 on glioblastoma multiforme cells

Glioblastoma multiforme (GBM) is the worst and most common brain tumor, characterized by high proliferation and invasion rates. The current standard treatment is mainly based on chemoradiotherapy and this approach has slightly improved patient survival. Thus, novel strategies aimed at prolonging the survival and ensuring a better quality of life are necessary. In the present work, we investigated the antitumoral effect of the novel analogue of calcitriol EM1 on GBM cells employing in vitro, in silico, and in vivo assays. In vitro, we demonstrated that EM1 treatment selectively decreases the viability of murine and human tumor cells without affecting that of normal human astrocytes. The analysis of the mechanisms showed that EM1 produces cell cycle arrest in the T98G cell line, which is accompanied by an increase in p21, p27, p57 protein levels and a decrease in cyclin D1, p-Akt-S473, p-ERK1/2 and c-Jun expression. Moreover, EM1 treatment also exerts in GBM cells anti-migratory effects and decreases their invasive capacity by a reduction in MMP-9 proteolytic activity. In silico, we demonstrated that EM1 is able to bind to the vitamin D receptor with greater affinity than calcitriol. Finally, we showed that EM1 treatment of nude mice administered at 50ug/kg body weight during 21days neither induces hypercalcemia nor toxicity effects. In conclusion, all the results indicate the potential of EM1 analogue as a promising therapeutic alternative for GBM treatment.

Clinical Cancer Advances 2018: Annual Report on Progress Against Cancer From the American Society of Clinical Oncology

A MESSAGE FROM ASCO'S PRESIDENT I remember when ASCO first conceived of publishing an annual report on the most transformative research occurring in cancer care. Thirteen reports later, the progress we have chronicled is remarkable, and this year is no different. The research featured in ASCO's Clinical Cancer Advances 2018 report underscores the impressive gains in our understanding of cancer and in our ability to tailor treatments to tumors' genetic makeup. The ASCO 2018 Advance of the Year, adoptive cell immunotherapy, allows clinicians to genetically reprogram patients' own immune cells to find and attack cancer cells throughout the body. Chimeric antigen receptor (CAR) T-cell therapy-a type of adoptive cell immunotherapy-has led to remarkable results in young patients with acute lymphoblastic leukemia (ALL) and in adults with lymphoma and multiple myeloma. Researchers are also exploring this approach in other types of cancer. This advance would not be possible without robust federal investment in cancer research. The first clinical trial of CAR T-cell therapy in children with ALL was funded, in part, by grants from the National Cancer Institute (NCI), and researchers at the NCI Center for Cancer Research were the first to report on possible CAR T-cell therapy for multiple myeloma. These discoveries follow decades of prior research on immunology and cancer biology, much of which was supported by federal dollars. In fact, many advances that are highlighted in the 2018 Clinical Cancer Advances report were made possible thanks to our nation's support for biomedical research. Funding from the US National Institutes of Health and the NCI helps researchers pursue critical patient care questions and addresses vital, unmet needs that private industry has little incentive to take on. Federally supported cancer research generates the biomedical innovations that fuel the development and availability of new and improved treatments for patients. We need sustained federal research investment to accelerate the discovery of the next generation of cancer treatments. Another major trend in this year's report is progress in precision medicine approaches to treat cancer. Although precision medicine offers promise to people with cancer and their families, that promise is only as good as our ability to make these treatments available to all patients. My presidential theme, "Delivering Discoveries: Expanding the Reach of Precision Medicine," focuses on tackling this formidable challenge so that new targeted therapies are accessible to anyone who faces a cancer diagnosis. By improving access to high-quality care, harnessing big data on patient outcomes from across the globe, and pursuing innovative clinical trials, I am optimistic that we will speed the delivery of these most promising treatments to more patients. Sincerely, Bruce E. Johnson, FASCO ASCO President, 2017 to 2018.

Survival benefit of glioblastoma patients after FDA approval of temozolomide concomitant with radiation and bevacizumab: A population-based study

Few population-based analyses have investigated survival change in glioblastoma multiforme (GBM) patients treated with concomitant radiotherapy-temozolomide (RT-TMZ) and adjuvant temozolomide (TMZ) and then bevacizumab (BEV) after Food and Drug Administration (FDA) approval, respectively. We aimed to explore the effects on survival with RT-TMZ, adjuvant TMZ and BEV in general GBM population based on the Surveillance, Epidemiology, and End Results (SEER) and Texas Cancer Registry (TCR) databases. A total of 28933 GBM patients from SEER (N = 24578) and TCR (N = 4355) between January 2000 and December 2013 were included. Patients were grouped into three calendar periods based on date of diagnosis: pre-RT-TMZ and pre-BEV (1/2000-2/2005, P1), post-RT-TMZ and pre-BEV (3/2005-4/2009, P2), and post-RT-TMZ and post-BEV (5/2009-12/2013, P3). The association between calendar period of diagnosis and survival was analyzed in SEER and TCR, separately, by the Kaplan-Meier method and Cox proportional hazards model. We found a significant increase in median overall survival (OS) across the three periods in both populations. In multivariate models, the risk of death was significantly reduced during P2 and further decreased in P3, which remained unchanged after stratification. Comparison and validation analysis were performed in the combined dataset, and consistent results were observed. We conclude that the OS of GBM patients in a "real-world" setting has been steadily improved from January 2000 to December 2013, which likely resulted from the administrations of TMZ concomitant with RT and adjuvant TMZ for newly diagnosed GBM and then BEV for recurrent GBM after respective FDA approval.

Phase I/II trial of vorinostat combined with temozolomide and radiation therapy for newly diagnosed glioblastoma: results of Alliance N0874/ABTC 02

Background

Vorinostat, a histone deacetylase (HDAC) inhibitor, has shown radiosensitizing properties in preclinical studies. This open-label, single-arm trial evaluated the maximum tolerated dose (MTD; phase I) and efficacy (phase II) of vorinostat combined with standard chemoradiation in newly diagnosed glioblastoma.

Methods

Patients received oral vorinostat (300 or 400 mg/day) on days 1-5 weekly during temozolomide chemoradiation. Following a 4- to 6-week rest, patients received up to 12 cycles of standard adjuvant temozolomide and vorinostat (400 mg/day) on days 1-7 and 15-21 of each 28-day cycle. Association between vorinostat response signatures and progression-free survival (PFS) and overall survival (OS) was assessed based on RNA sequencing of baseline tumor tissue.

Results

Phase I and phase II enrolled 15 and 107 patients, respectively. The combination therapy MTD was vorinostat 300 mg/day and temozolomide 75 mg/m2/day. Dose-limiting toxicities were grade 4 neutropenia and thrombocytopenia and grade 3 aspartate aminotransferase elevation, hyperglycemia, fatigue, and wound dehiscence. The primary efficacy endpoint in the phase II cohort, OS rate at 15 months, was 55.1% (median OS 16.1 mo), and consequently, the study did not meet its efficacy objective. Most common treatment-related grade 3/4 toxicities in the phase II component were lymphopenia (32.7%), thrombocytopenia (28.0%), and neutropenia (21.5%). RNA expression profiling of baseline tumors (N = 76) demonstrated that vorinostat resistance (sig-79) and sensitivity (sig-139) signatures had a reverse and positive association with OS/PFS, respectively.

Conclusions

Vorinostat combined with standard chemoradiation had acceptable tolerability in newly diagnosed glioblastoma. Although the primary efficacy endpoint was not met, vorinostat sensitivity and resistance signatures could facilitate patient selection in future trials.

Antitumor Activity of Fascaplysin Derivatives on Glioblastoma Model In Vitro

Antitumor efficiency of fascaplysin synthetic derivatives (7-phenylfascaplysin, 3-chlorofascaplysin, 3-bromofascaplysin, and 10-bromofascaplysin) was compared out in vitro on C6 glioma cells. The cytotoxic efficiency of all tested compounds was higher than that of unsubstituted fascaplysin; 3-bromofascaplysin and 7-phenylfascaplysin exhibited the best capacity to kill glioma C6 cells. Apoptosis was the main mechanism of glioma cell death. The cytotoxic activity of these compounds increased with prolongation of exposure to the substance and increase of its concentration. Fascaplysin derivatives modified all phases of glioma cell vital cycle. The count of viable tumor cell in G0 phase remained minimum by the end of experiment under the effects of 3-bromofascaplysin and 7-phenylfascaplysin.

Dosimetric Impact of a Tumor Treating Fields Device for Glioblastoma Patients Undergoing Simultaneous Radiation Therapy

Purpose

A recent randomized phase III clinical trial in patients with glioblastoma demonstrated the efficacy of tumor treating fields (TTFields), in which alternating electric fields are applied via transducer arrays to a patient’s scalp. This treatment, when added to standard of care therapy, was shown to increase overall survival from 16 to 20.9 months. These results have generated significant interest in incorporating the use of TTFields during postoperative concurrent chemoradiation. However, the dosimetric impact of high-density electrodes on the scalp, within the radiation field, is unknown.

Methods

The dosimetric impact of TTFields electrodes in the radiation field was quantified in two ways: (1) dose calculated in a treatment planning system and (2) physical measurements of surface and deep doses. In the dose calculation comparison, a volumetric-modulated-arc-therapy (VMAT) radiation plan was developed on a CT scan without electrodes and then recalculated with electrodes. For physical measurements, the surface dose underneath TTFields electrodes were measured using a parallel plate ionization chamber and compared to measurements without electrodes for various incident beam angles and for 12 VMAT arc deliveries. Deep dose measurements were conducted for five VMAT plans using Scandidos Delta4 diode array: measured doses on two orthogonal diode arrays were compared.

Results

In the treatment planning system, the presence of the TTFields device caused mean reduction of PTV dose of 0.5–1%, and a mean increase in scalp dose of 0.5–1 Gy. Physical measurement showed increases of surface dose directly underneath by 30–110% for open fields with varying beam angles and by 70–160% for VMAT deliveries. Deep dose measurement by diode array showed dose decrease of 1–2% in most areas shadowed by the electrodes (max decrease 2.54%).

Conclusion

The skin dose in patients being treating with cranial irradiation for glioblastoma may increase substantially (130–260%) with the addition of concurrent TTFields electrodes on the scalp. However, the impact of dose attenuation by the electrodes on deep dose during VMAT treatment is of much smaller, but measureable, magnitude (1–2%). Clinical trials exploring concurrent TTFields with cranial irradiation for glioblastoma may utilize scalp-sparing techniques to mitigate any potential increase in skin toxicity.