A phase 2 trial of irinotecan (CPT-11) in patients with recurrent malignant glioma: a North American Brain Tumor Consortium study

Bevacizumab Alone Versus Bevacizumab Plus Irinotecan in Patients With Recurrent Glioblastoma: A Nationwide Population-Based Study

BACKGROUND

For treating recurrent glioblastoma, for which there is no established treatment, the antiangiogenic antibody, bevacizumab, is used alone or with irinotecan. This study was aimed at comparing the survival of patients with recurrent glioblastoma receiving bevacizumab monotherapy and those receiving bevacizumab plus irinotecan combination therapy (B+I) by using a nationwide population-based dataset.

METHODS

Patients matching the International Classification of Diseases code C71.x were screened from the Health Insurance Review and Assessment Service database. From January 2008 to November 2021, patients who underwent surgery or biopsy and subsequent standard concurrent chemoradiation with temozolomide were included. Among them, those who received bevacizumab monotherapy or B+I were selected. Demographic characteristics, inpatient stay, prescription frequency, survival outcomes, and steroid prescription duration were compared between these two groups.

RESULTS

Eight hundred and forty-six patients who underwent surgery or biopsy and received concurrent chemoradiotherapy with temozolomide were included. Of these, 450 and 396 received bevacizumab monotherapy and B+I, respectively. The corresponding median overall survival from the initial surgery was 22.60 months (95% confidence interval [CI], 20.50-24.21) and 20.44 months (95% CI, 18.55-22.60; P = 0.508, log-rank test). The B+I group had significantly more bevacizumab prescriptions (median 5 times; BEV group: median 3 times). Cox analysis, based on the postsurgery period, revealed that male sex (hazard ratio [HR], 1.28; P = 0.002), older age (HR, 1.01; P = 0.042), and undergoing biopsy instead of surgery (HR, 1.79; P < 0.0001) were significantly associated with decreased survival. Fewer radiotherapy cycles correlated with improved survival outcomes (HR, 0.63; P = 0.001). Cox analysis, conducted from the start of chemotherapy including bevacizumab, showed that male sex was the only variable significantly associated with decreased survival (HR, 1.18; P = 0.044).

CONCLUSION

We found no significant difference in overall survival between the bevacizumab monotherapy and B+I groups. Considering the additional potential toxicity associated with irinotecan, bevacizumab monotherapy could be a suitable treatment option for treating recurrent glioblastoma.

Local Delivery of Irinotecan to Recurrent GBM Patients at Reoperation Offers a Safe Route of Administration

Glioblastomas are impossible to completely resect and almost always recur at the borders of the resection margin. There is no established chemotherapy regimen available to patients who recur, while systemic treatment is hampered by the blood-brain barrier. Here, we report on the first evaluation in humans of the intraparenchymal injection of irinotecan into the resection cavity after surgical resection of recurrent glioblastoma patients. The cytotoxicity of irinotecan was compared to SN-38 in primary cells from recurrent glioblastoma patients. Irinotecan was injected at multiple (~30) sites of the resection cavity wall at a depth of 3 to 5 mm. SN-38 was more cytotoxic than irinotecan at concentrations below 1 µM due to enzyme kinetics. The intraparenchymal administration of irinotecan was safe, with good wound healing and an absence of swelling, inflammation, or pseudo-abscess formation. The median survival post irinotecan administration was 32.6 weeks. The median overall survival was 30.5 months, with a two-year survival rate of 56%. This study demonstrates that local delivery of irinotecan into the brain parenchyma offers a safe route of administration over systemic delivery in the treatment of recurrent glioblastoma.

Mechanisms of telomere maintenance and associated therapeutic vulnerabilities in malignant gliomas

A majority of cancers (~85%) activate the enzyme telomerase to maintain telomere length over multiple rounds of cellular division. Telomerase-negative cancers activate a distinct, telomerase-independent mechanism of telomere maintenance termed alternative lengthening of telomeres (ALT). ALT uses homologous recombination to maintain telomere length and exhibits features of break-induced DNA replication. In malignant gliomas, the activation of either telomerase or ALT is nearly ubiquitous in pediatric and adult tumors, and the frequency with which these distinct telomere maintenance mechanisms (TMMs) is activated varies according to genetically defined glioma subtypes. In this review, we summarize the current state of the field of TMMs and their relevance to glioma biology and therapy. We review the genetic alterations and molecular mechanisms leading to telomerase activation or ALT induction in pediatric and adult gliomas. With this background, we review emerging evidence on strategies for targeting TMMs for glioma therapy. Finally, we comment on critical gaps and issues for moving the field forward to translate our improved understanding of glioma telomere maintenance into better therapeutic strategies for patients.

Targeting brain tumors with innovative nanocarriers: bridging the gap through the blood-brain barrier

Background

Glioblastoma multiforme (GBM) is recognized as the most lethal and most highly invasive tumor. The high likelihood of treatment failure arises from the presence of the blood-brain barrier (BBB) and stem cells around GBM, which avert the entry of chemotherapeutic drugs into the tumor mass.

Objective

Recently, several researchers have designed novel nanocarrier systems like liposomes, dendrimers, metallic nanoparticles, nanodiamonds, and nanorobot approaches, allowing drugs to infiltrate the BBB more efficiently, opening up innovative avenues to prevail over therapy problems and radiation therapy.

Methods

Relevant literature for this manuscript has been collected from a comprehensive and systematic search of databases, for example, PubMed, Science Direct, Google Scholar, and others, using specific keyword combinations, including "glioblastoma," "brain tumor," "nanocarriers," and several others.

Conclusion

This review also provides deep insights into recent advancements in nanocarrier-based formulations and technologies for GBM management. Elucidation of various scientific advances in conjunction with encouraging findings concerning the future perspectives and challenges of nanocarriers for effective brain tumor management has also been discussed.

Anti-Cancer Effect of Neural Stem Cells Transfected with Carboxylesterase and sTRAIL Genes in Animals with Brain Lesions of Lung Cancer

A metastatic brain tumor is the most common type of malignancy in the central nervous system, which is one of the leading causes of death in patients with lung cancer. The purpose of this study is to evaluate the efficacy of a novel treatment for metastatic brain tumors with lung cancer using neural stem cells (NSCs), which encode rabbit carboxylesterase (rCE) and the secretion form of tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL). rCE and/or sTRAIL were transduced in immortalized human fetal NSCs, HB1.F3. The cytotoxic effects of the therapeutic cells on human lung cancer cells were evaluated in vitro with the ligands and decoy receptor expression for sTRAIL in the presence of CPT-11. Human NSCs encoding rCE (F3.CE and F3.CE.sTRAIL) significantly inhibited the growth of lung cancer cells in the presence of CPT-11 in vitro. Lung cancer cells were inoculated in immune-deficient mice, and therapeutic cells were transplanted systematically through intracardiac arterial injection and then treated with CPT-11. In resting state, DR4 expression in lung cancer cells and DcR1 in NSCs increased to 70% and 90% after CPT-11 addition, respectively. The volumes of the tumors in immune-deficient mice were reduced significantly in mice with F3.CE.sTRAIL transplantation and CPT-11 treatment. The survival was also significantly prolonged with treatment with F3.sTRAIL and F3.CE plus CPT-11 as well as F3.CE.sTRAIL plus CPT-11. NSCs transduced with rCE and sTRAIL genes showed a significant anti-cancer effect on brain metastatic lung cancer in vivo and in vitro, and the effect may be synergistic when rCE/CPT-11 and sTRAIL are combined. This stem-cell-based study using two therapeutic genes of different biological effects can be translatable to clinical application.

Phase II study of border zone stereotactic radiosurgery with bevacizumab in patients with recurrent or progressive glioblastoma multiforme

PURPOSE

Recurrent glioblastoma is universally fatal with limited effective treatment options. The aim of this phase 2 study of Border Zone SRS plus bevacizumab was to evaluate OS in patients with recurrent GBM.

METHODS

Patients with histologically confirmed GBM with recurrent disease who had received prior first-line treatment with fractionated radiotherapy and chemotherapy and eligible for SRS were enrolled. Bevacizumab 10 mg/kg was given day -1, day 14, and then every 14 days until disease progression. 1-14 days before BZ-SRS procedure, patients underwent brain MRI /MRS. MRS with measurement of choline-to-N-acetyl aspartate index (CNI) area ≥ 3 was targeted for SRS.

RESULTS

From 2015-2017, sixteen of planned 40 patients were enrolled. The median age was 62 (range, 48-74Y). 3/16 (0.188) participants experienced grade 2 toxicity. No AREs were reported. The mOS was 11.73 months compared to 8.74 months (P = 0.324) from date of SRS for the BZ-SRS and institutional historical controls, respectively. PFS-6 and OS-6 were 31.2% (p = 0.00294) and 81.2%(p = 0.058), respectively. Of 13 evaluable for best response: 1 CR (p = 0.077), 4 PR (p = 0.308), 7 SD (p = 0.538), and 1 PD (p = 0.077). 11/16 participants had MRS scans with an estimated probability that MRS changes a treatment plan of 0 (0, 0.285).

CONCLUSION

BZ-SRS with bevacizumab was feasible and well tolerated. There is no significant survival benefit using BZ-SRS with bevacizumab compared to institutional historical controls. Secondary analysis revealed a trend toward improved PFS-6, but not OS-6 after BZ-SRS. MRS scans did not result in changes to SRS treatment plans.

A Potential New Treatment for High-Grade Glioma: A Study Assessing Repurposed Drug Combinations against Patient-Derived High-Grade Glioma Cells

Repurposed drugs have demonstrated in vitro success against high-grade gliomas; however, their clinical success has been limited due to the in vitro model not truly representing the clinical scenario. In this study, we used two distinct patient-derived tumour fragments (tumour core (TC) and tumour margin (TM)) to generate a heterogeneous, clinically relevant in vitro model to assess if a combination of repurposed drugs (irinotecan, pitavastatin, disulfiram, copper gluconate, captopril, celecoxib, itraconazole and ticlopidine), each targeting a different growth promoting pathway, could successfully treat high-grade gliomas. To ensure the clinical relevance of our data, TC and TM samples from 11 different patients were utilized. Our data demonstrate that, at a concentration of 100µm or lower, all drug combinations achieved lower LogIC50 values than temozolomide, with one of the combinations almost eradicating the cancer by achieving cell viabilities below 4% in five of the TM samples 6 days after treatment. Temozolomide was unable to stop tumour growth over the 14-day assay, while combination 1 stopped tumour growth, with combinations 2, 3 and 4 slowing down tumour growth at higher doses. To validate the cytotoxicity data, we used two distinct assays, end point MTT and real-time IncuCyte life analysis, to evaluate the cytotoxicity of the combinations on the TC fragment from patient 3, with the cell viabilities comparable across both assays. The local administration of combinations of repurposed drugs that target different growth promoting pathways of high-grade gliomas have the potential to be translated into the clinic as a novel treatment strategy for high-grade gliomas.

Targeted delivery of irinotecan and SLP2 shRNA with GRP-conjugated magnetic graphene oxide for glioblastoma treatment

Magnetic nanoparticles (MNPs) are useful for magnetic targeted drug delivery while ligand-mediated active targeting is another common delivery strategy for cancer therapy. In this work, we intend to prepare magnetic graphene oxide (mGO) by chemical co-precipitation of MNPs on the GO surface, followed by conjugation of the gastrin releasing peptide (GRP) as a targeting ligand, for dual targeted drug/gene delivery in invasive brain glioma treatment. mGO was grafted with chitosan, complexed with shRNA plasmid DNA for stomatin-like protein 2 (SLP2) gene silencing, modified with urocanic acid for plasmid DNA endosomal escape, PEGylated for GRP conjugation, and loaded with the chemotherapeutic drug irinotecan (CPT-11) by π-π interaction for pH-responsive drug release (mGOCUG/CPT-11/shRNA). In addition to the in depth characterization of the physico-chemical and biological properties during each preparation step, we also study the loading/pH-responsive release behavior of CPT-11 and the shRNA plasmid loading/cell transfection efficiency. The targeting and antitumor efficacies of the nanocomposite were studied with U87 human glioblastoma cells in vitro. An in vivo study revealed that intravenous administration followed by magnetic guidance results in the efficient targeted delivery of mGOCUG/CPT-11/shRNA to orthotopic brain tumors in nude mice, and it exhibits excellent antitumor efficacy with a reduced tumor growth rate and prolonged animal survival time. Our work thus highlights a multifunctional mGO-based drug/gene delivery platform for effective combination cancer therapy in glioblastoma treatment.

Glioblastoma multiforme (GBM): An overview of current therapies and mechanisms of resistance

Glioblastoma multiforme (GBM) is a WHO grade IV glioma and the most common malignant, primary brain tumor with a 5-year survival of 7.2%. Its highly infiltrative nature, genetic heterogeneity, and protection by the blood brain barrier (BBB) have posed great treatment challenges. The standard treatment for GBMs is surgical resection followed by chemoradiotherapy. The robust DNA repair and self-renewing capabilities of glioblastoma cells and glioma initiating cells (GICs), respectively, promote resistance against all current treatment modalities. Thus, durable GBM management will require the invention of innovative treatment strategies. In this review, we will describe biological and molecular targets for GBM therapy, the current status of pharmacologic therapy, prominent mechanisms of resistance, and new treatment approaches. To date, medical imaging is primarily used to determine the location, size and macroscopic morphology of GBM before, during, and after therapy. In the future, molecular and cellular imaging approaches will more dynamically monitor the expression of molecular targets and/or immune responses in the tumor, thereby enabling more immediate adaptation of tumor-tailored, targeted therapies.

Emerging Nano-Carrier Strategies for Brain Tumor Drug Delivery and Considerations for Clinical Translation

Treatment of brain tumors is challenging since the blood–brain tumor barrier prevents chemotherapy drugs from reaching the tumor site in sufficient concentrations. Nanomedicines have great potential for therapy of brain disorders but are still uncommon in clinical use despite decades of research and development. Here, we provide an update on nano-carrier strategies for improving brain drug delivery for treatment of brain tumors, focusing on liposomes, extracellular vesicles and biomimetic strategies as the most clinically feasible strategies. Finally, we describe the obstacles in translation of these technologies including pre-clinical models, analytical methods and regulatory issues.

Current evidence and challenges of systematic therapies for adult recurrent glioblastoma: Results from clinical trials

Recurrence is a major concern for adult patients with glioblastomas (GBMs), and the prognosis remains poor. Although several therapies have been assessed, most of them have not achieved satisfactory results. Therefore, there is currently no standard treatment for adult recurrent GBM (rGBM). Here, we review the results of clinical trials for the systematic therapy of rGBM. Regorafenib, rindopepimut and neoadjuvant programmed death 1 (PD-1) inhibitors are promising agents for rGBM, while regorafenib is effective in both O⁶-methylguanine DNA methyltransferase (MGMT) promoter methylated and unmethylated patients. Temozolomide rechallenge and alkylating agents combined with bevacizumab can be useful for patients with MGMT methylation, and patients with isocitrate dehydrogenase (IDH) mutations or second recurrence can benefit from vocimagene amiretrorepvec (Toca 511). Some phase I trials on targeted therapy and immunotherapy have shown positive results, and results from further studies are expected. In addition to the analysis of existing clinical trial results, forthcoming trials should be well designed, and patients are encouraged to participate in appropriate clinical trials.

Injectable Thermo-Sensitive Chitosan Hydrogel Containing CPT-11-Loaded EGFR-Targeted Graphene Oxide and SLP2 shRNA for Localized Drug/Gene Delivery in Glioblastoma Therapy

In this study, we aimed to develop a multifunctional drug/gene delivery system for the treatment of glioblastoma multiforme by combining the ligand-mediated active targeting and the pH-triggered drug release features of graphene oxide (GO). Toward this end, we load irinotecan (CPT-11) to cetuximab (CET)-conjugated GO (GO-CET/CPT11) for pH-responsive drug release after endocytosis by epidermal growth factor receptor (EGFR) over-expressed U87 human glioblastoma cells. The ultimate injectable drug/gene delivery system was designed by co-entrapping stomatin-like protein 2 (SLP2) short hairpin RNA (shRNA) and GO-CET/CPT11 in thermosensitive chitosan-g-poly(N-isopropylacrylamide) (CPN) polymer solution, which offers a hydrogel depot for localized, sustained delivery of the therapeutics after the in situ formation of CPN@GO-CET/CPT11@shRNA hydrogel. An optimal drug formulation was achieved by considering both the loading efficiency and loading content of CPT-11 on GO-CET. A sustained and controlled release behavior was found for CPT-11 and shRNA from CPN hydrogel. Confocal microscopy analysis confirmed the intracellular trafficking for the targeted delivery of CPT-11 through interactions of CET with EGFR on the U87 cell surface. The efficient transfection of U87 using SLP2 shRNA was achieved using CPN as a delivery milieu, possibly by the formation of shRNA/CPN polyplex after hydrogel degradation. In vitro cell culture experiments confirmed cell apoptosis induced by CPT-11 released from acid organelles in the cytoplasm by flow cytometry, as well as reduced SLP2 protein expression and inhibited cell migration due to gene silencing. Finally, in vivo therapeutic efficacy was demonstrated using the xenograft of U87 tumor-bearing nude mice through non-invasive intratumoral delivery of CPN@GO-CET/CPT11@shRNA by injection. Overall, we have demonstrated the novelty of this thermosensitive hydrogel to be an excellent depot for the co-delivery of anticancer drugs and siRNA. The in situ forming hydrogel will not only provide extended drug release but also combine the advantages offered by the chitosan-based copolymer structure for siRNA delivery to broaden treatment modalities in cancer therapy.

Overcoming the blood-brain barrier by Annexin A1-binding peptide to target brain tumours

Background

Annexin A1 is expressed specifically on the tumour vasculature surface. Intravenously injected IF7 targets tumour vasculature via annexin A1. We tested the hypothesis that IF7 overcomes the blood–brain barrier and that the intravenously injected IF7C(RR)-SN38 eradicates brain tumours in the mouse.

Methods

(1) A dual-tumour model was generated by inoculating luciferase-expressing melanoma B16 cell line, B16-Luc, into the brain and under the skin of syngeneic C57BL/6 mice. IF7C(RR)-SN38 was injected intravenously daily at 7.0 μmoles/kg and growth of tumours was assessed by chemiluminescence using an IVIS imager. A similar dual-tumour model was generated with the C6-Luc line in immunocompromised SCID mice. (2) IF7C(RR)-SN38 formulated with 10% Solutol HS15 was injected intravenously daily at 2.5 μmoles/kg into two brain tumour mouse models: B16-Luc cells in C57BL/6 mice, and C6-Luc cells in nude mice.

Results

(1) Daily IF7C(RR)-SN38 injection suppressed tumour growth regardless of cell lines or mouse strains. (2) Daily injection of Solutol-formulated IF7C(RR)-SN38 led into complete disappearance of B16-Luc brain tumour in C57BL/6 mice, whereas this did not occur in C6-Luc in nude mice.

Conclusions

IF7C(RR)-SN38 crosses the blood–brain barrier and suppresses growth of brain tumours in mouse models. Solutol HS15-formulated IF7C(RR)-SN38 may have promoted an antitumour immune response.

Identification and validation of a six-lncRNA prognostic signature with its ceRNA networks and candidate drugs in lower-grade gliomas

Gliomas account for 75% of the primary malignant brain tumors and a majority of lower-grade gliomas (LGG) inevitably develop into glioblastoma. The dysregulation of lncRNAs play a crucial role in LGG. In the present study, we first screened out six differentially expressed lncRNAs (AC021739.2, AL031722.1, AL354740.1, FGD5-AS1, LINC00844, and NEAT1) based on TCGA and GTEx RNA-seq databases. LncRNA prognostic signature was then established by Kaplan-Meier and multivariate Cox proportional hazards regression, with its predictive value validated by time-dependent receiver operating characteristic (ROC) curves. After lncRNA-miRNA-mRNA regulatory networks were established by Cytoscape 3.7.2, Gene Oncology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed, with results enriched in various malignancy-related functions and pathways. Finally, six putative drugs (irinotecan, camptothecin, mitoxantrone, azacitidine, mestranol, and enilconazole) were predicted by Connectivity Map. In conclusion, we identified a 6-lncRNA prognostic signature with its ceRNA networks, and six candidate drugs against LGG.

Development and in vivo evaluation of Irinotecan-loaded Drug Eluting Seeds (iDES) for the localised treatment of recurrent glioblastoma multiforme

Glioblastoma multiforme (GBM) is impossible to fully remove surgically and almost always recurs at the borders of the resection cavity, while systemic delivery of therapeutic drug levels to the brain tumour is limited by the blood-brain barrier. This research describes the development of a novel formulation of Irinotecan-loaded Drug Eluting Seeds (iDES) for insertion into the margin of the GBM resection cavity to provide a sustained high local dose with reduced systemic toxicities. We used primary GBM cells from both the tumour core and Brain Around the Tumour tissue from recurrent GBM patients to demonstrate that irinotecan is more effective than temozolomide. Irinotecan had a 75% response rate, while only 50% responded to temozolomide. With temozolomide the cell viability was never below 80% whereas irinotecan achieved cell viabilities of less than 44%. The iDES were manufactured using a hot melt extrusion process with accurate irinotecan drug loadings and the same cytotoxicity as unformulated irinotecan. The iDES released irinotecan in a sustained fashion for up to 7 days. However, only the 30, 40 and 50% w/w loaded iDES formulations released the 300 to 1000 μg of irinotecan needed to be effective in vivo. The 30 and 40% w/w iDES formulations containing 10% plasticizer and either 60 or 50% PLGA prolonged survival from 27 to 70 days in a GBM xenograft mouse resection model with no sign of tumour recurrence. The 30% w/w iDES formulations showed equivalent toxicity to a placebo in non-tumour bearing mice. This innovative drug delivery approach could transform the treatment of recurrent GBM patients by improving survival and reducing toxicity.

Combining therapy with recombinant human endostatin and cytotoxic agents for recurrent disseminated glioblastoma: a retrospective study

BACKGROUND

The optimal chemotherapeutics of recurrent disseminated glioblastoma has yet to be determined. We analyzed the efficacy and safety of recombinant human endostatin (rh-ES) combined with temozolomide and irinotecan in patients with recurrent disseminated glioblastoma.

METHODS

We retrospectively reviewed 30 adult patients with recurrent disseminated glioblastoma treated with this combination chemotherapy at Department of Neuro-Oncology, Sanbo Brain Hospital, Capital Medical University of China from November 2009 to August 2018. Temozolomide was given orally at 200 mg/m² daily for 5 days and rh-ES was administrated 15 mg/d daily for 14 days of each 28-day treatment cycle. Irinotecan was given intravenously every 2 weeks on a 28-day cycle at 340 mg/m² or 125 mg/m² depending on antiepileptic drugs. Primary endpoint was progression-free survival (PFS) at 6 months (6 m-PFS).

RESULTS

The 6 m-PFS was 23.3%. The median PFS was 3.2 months. The overall survival rate (OS) at 12 months was 28.6%. The median OS was 6.9 months. Six out of 30 (20%) patients demonstrated partial radiographic response and 11 (36.7%) remained stable. The PFS of the 6 patients who got partial response was 5.8, 6.3, 6.9, 13.6, 15.8 and 16.6 months, respectively, and the median time interval of first response was 4 (range, 2.0-6.6) months. The most common adverse events were hematologic toxicities and gastrointestinal effects. The Grade ≥ 3 adverse event was hematologic toxicities. The adverse events were manageable.

CONCLUSIONS

Rh-ES, in combination with cytotoxic drugs, was an alternative effective regimen with manageable toxicities in treatment of recurrent disseminated glioblastoma.

Volumetric response quantified using T1 subtraction predicts long-term survival benefit from cabozantinib monotherapy in recurrent glioblastoma

Background

To overcome challenges with traditional response assessment in anti-angiogenic agents, the current study uses T1 subtraction maps to quantify volumetric radiographic response in monotherapy with cabozantinib, an orally bioavailable tyrosine kinase inhibitor with activity against vascular endothelial growth factor receptor 2 (VEGFR2), hepatocyte growth factor receptor (MET), and AXL, in an open-label, phase II trial in patients with recurrent glioblastoma (GBM) (NCT00704288).

Methods

A total of 108 patients with adequate imaging data and confirmed recurrent GBM were included in this retrospective study from a phase II multicenter trial of cabozantinib monotherapy (XL184-201) at either 100 mg (N = 87) or 140 mg (N = 21) per day. Contrast enhanced T1-weighted digital subtraction maps were used to define volume of contrast-enhancing tumor at baseline and subsequent follow-up time points. Volumetric radiographic response (>65% reduction in contrast-enhancing tumor volume from pretreatment baseline tumor volume sustained for more than 4 wk) was tested as an independent predictor of overall survival (OS).

Results

Volumetric response rate for all therapeutic doses was 38.9% (41.4% and 28.6% for 100 mg and 140 mg doses, respectively). A log-linear association between baseline tumor volume and OS (P = 0.0006) and a linear correlation between initial change in tumor volume and OS (P = 0.0256) were observed. A significant difference in OS was observed between responders (median OS = 20.6 mo) and nonresponders (median OS = 8.0 mo) (hazard ratio [HR] = 0.3050, P < 0.0001). Multivariable analyses showed that continuous measures of baseline tumor volume (HR = 1.0233, P < 0.0001) and volumetric response (HR = 0.2240, P < 0.0001) were independent predictors of OS.

Conclusions

T1 subtraction maps provide value in determining response in recurrent GBM treated with cabozantinib and correlated with survival benefit.

Risk of Adverse Vascular Events in Patients with Malignant Glioma Treated with Bevacizumab Plus Irinotecan: A Systematic Review and Meta-Analysis

BACKGROUND

Bevacizumab plus irinotecan is a new beneficial chemotherapy strategy for patients with malignant glioma. The purpose of this systematic review and meta-analysis was to comprehensively assess the risk of adverse vascular events in adults with malignant glioma treated with bevacizumab plus irinotecan.

METHODS

The Cochrane Library, Embase and PubMed were searched, and relevant trials were identified up to June 2018. Two investigators screened all titles and abstracts for possible inclusion and extracted data independently. Six studies were included, and 5 of them in the control group using bevacizumab alone or bevacizumab with temozolomide. Three systems were used to assess the quality of evidence and the level of recommendation. The Oxford Centre for Evidence-Based Medicine Levels of Evidence (2009) system was used to classify the evidence into 5 levels (classes I-V). The star system from the Newcastle-Ottawa Scale was used to assess methodological quality. The GRADE profiler was used to evaluate the overall body of evidence.

RESULTS

Our data show that bevacizumab plus irinotecan therapy does not significantly affect the risk of systemic adverse events (odds ratio [OR], 1.17; 95% confidence interval [CI], 0.43-3.18). Patients treated with bevacizumab plus irinotecan had a similar risk of hematotoxicity (OR, 1.06; 95% CI, 0.26-4.38), thrombocytopenia (OR, 1.07; 95% CI, 0.25-4.63), and hypertension (OR, 1.34; 95% CI, 0.28-6.36) compared with the control group (those treated without irinotecan). Thrombosis occurred more frequently in patients treated with bevacizumab plus irinotecan compared with the control group (OR, 3.23; 95% CI, 1.47-7.12).

CONCLUSIONS

The risk of systemic adverse events was not significantly different between patients with malignant glioma treated with bevacizumab plus irinotecan and the control group. The risks of hematotoxicity, thrombocytopenia, and hypertension were similar in the 2 groups. The risk of thrombosis was higher in patients treated with bevacizumab plus irinotecan. Monitoring for thrombosis and administering anticoagulant therapy as necessary merit promotion for patients with malignant glioma receiving treatment with bevacizumab plus irinotecan.

Neural Stem Cells

Neural stem cell (NSC) transplantation has provided the basis for the development of potentially powerful new therapeutic cell-based strategies for a broad spectrum of clinical diseases, including stroke, psychiatric illnesses such as fetal alcohol spectrum disorders, and cancer. Here, we discuss pertinent preclinical investigations involving NSCs, including how NSCs can ameliorate these diseases, the current barriers hindering NSC-based treatments, and future directions for NSC research. There are still many translational requirements to overcome before clinical therapeutic applications, such as establishing optimal dosing, route of delivery, and timing regimens and understanding the exact mechanism by which transplanted NSCs lead to enhanced recovery. Such critical lab-to-clinic investigations will be necessary in order to refine NSC-based therapies for debilitating human disorders.

Modern reirradiation for recurrent gliomas can safely delay tumor progression

BACKGROUND

Despite advances in modern therapy, high-grade gliomas continue to portend a dismal prognosis and nearly all patients will experience relapse. Unfortunately, salvage options remain limited. In this study, we assessed outcomes for patients with recurrent gliomas treated with reirradiation.

METHODS

We retrospectively identified 48 glioma patients treated with reirradiation between 2013 and 2016. All had radiographic or pathologic evidence of recurrence. Prognostic factors were abstracted from the electronic medical record.

RESULTS

Initial surgery included biopsy in 15, subtotal resection in 21, and gross total resection in 12. Initial chemotherapy included temozolomide (TMZ) in 31, TMZ+dasatinib in 7, TMZ+vorinostat in 3, and procarbazine, lomustine, and vincristine in 2. The median dose of primary radiotherapy was 60 Gy delivered in 30 fractions. Median overall survival (OS) and progression-free survival (PFS) from initial diagnosis were 3.2 and 1.7 years, respectively. A total of 36 patients failed salvage bevacizumab before reirradiation. Salvage surgery was performed before reirradiation in 21 patients. Median time to reirradiation was 1.7 years. Median follow-up was 13.7 months from reirradiation. Concurrent systemic therapy was given in 33 patients (bevacizumab in 27, TMZ in 8, and lomustine in 2). Median PFS and OS after reirradiation were 3.2 and 6.3 months, respectively. Radionecrosis occurred in 4 patients and no radionecrosis was seen in patients receiving concurrent bevacizumab with reirradiation (0% vs 19%, P = .03).

CONCLUSIONS

Reirradiation may result in delayed tumor progression with acceptable toxicity. Prospective trials are needed to determine the impact of reirradiation on tumor progression and quality of life.

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

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

A retrospective survey of the last 3 months of life in patients carrying glioblastoma: Clinical treatments and profiles

Glioblastoma is one of the most common types of primary brain tumor. In situations of local recurrence, physicians can suggest either specific palliative anticancer treatments (SPAT; surgery, chemotherapy, radiotherapy) or best supportive care (BSC). The objective of the present study was to identify clinical factors that may have influenced the continuation or cessation of SPAT during the final 3 months of life in patients with glioblastoma. In the present retrospective single-center study, all records of patients treated for glioblastoma, who succumbed to the disease between June 2006 and February 2014, were assessed. All selected patients were divided into two groups, according to treatments received during the last 3 months of life: The SPAT and BSC groups. A total of 148 patients were included: 81 patients in the SPAT group (group A) and 67 patients in the BSC group (group B). A performance status equal to 0 was observed for 17.3% of patients in group A vs. 6% in group B. Following progression, chemotherapy was administered in 39.5% of cases in group A vs. 20.9% of cases in group B (P=0.0149). The mean number of lines of chemotherapy administered in group A was equal to 1.44±0.77 as compared with 1.06±0.67 in group B (P=0.0017). SPAT are utilized frequently among patients approaching mortality due to a glioblastoma. Certain factors, including the utilization of novel chemotherapy after the first progression or number of lines of chemotherapy previously administered, may have influenced physicians' decisions whether to continue with the SPAT or not.

A pilot clinical study of apatinib plus irinotecan in patients with recurrent high-grade glioma: Clinical Trial/Experimental Study

BACKGROUND

Malignant glioma is the most common primary malignant brain tumor that displays high vascularity, making vascular endothelial growth factor receptors become promising targets. This study was conducted to evaluate the efficacy and safety of apatinib, a new potent oral small-molecule tyrosine kinase inhibitor targeted vascular endothelial growth factor receptor 2, combined with irinotecan, in patients with recurrent malignant glioma.

METHODS

Ten patients with recurrent malignant glioma who were experiencing relapse after treatment of temozolomide were enrolled in this study. They received oral apatinib (500 mg qd) in conjunction with irinotecan (340 mg/m or 125 mg/m depending on use of enzyme-inducing antiepileptic drugs) for 6 cycles. After that the patients continued to take apatinib as maintenance. Dosage adjustment occurred in only 3 (30.0%) patients.

RESULTS

Among the 10 patients, 9 were available for the efficacy evaluation. There were 5 with partial response, 2 with stable disease and 2 with progressive disease. The objective response rate and the disease control rate (DCR) were 55% (5/9) and 78% (7/9), respectively. The median progress free survival time was 8.3 months. As for safety analysis, the most 3 common adverse events were gastrointestinal reaction (31.8%), hypertension (22.7%), and myelosuppression (18.0%).

CONCLUSION

Apatinib combined with irinotecan seems to be a promising therapeutic option for recurrent malignant glioma patients. Perspective clinical studies with adequate sample size are required to validate our results.

TRIAL REGISTRATION

NCT02848794 /Ahead-BG306.

Topotecan is a potent inhibitor of SUMOylation in glioblastoma multiforme and alters both cellular replication and metabolic programming

Protein SUMOylation is a dynamic post-translational modification shown to be involved in a diverse set of physiologic processes throughout the cell. SUMOylation has also been shown to play a role in the pathobiology of myriad cancers, one of which is glioblastoma multiforme (GBM). As such, the clinical significance and therapeutic utility offered via the selective control of global SUMOylation is readily apparent. There are, however, relatively few known/effective inhibitors of global SUMO-conjugation. Herein we describe the identification of topotecan as a novel inhibitor of global SUMOylation. We also provide evidence that inhibition of SUMOylation by topotecan is associated with reduced levels of CDK6 and HIF-1α, as well as pronounced changes in cell cycle progression and cellular metabolism, thereby highlighting its putative role as an adjuvant therapy in defined GBM patient populations.

Reported outcomes of children with newly diagnosed high-grade gliomas treated with nimotuzumab and irinotecan

PURPOSE

The outcome of children with high-grade gliomas (HGGs) treated with radiation and adjuvant chemotherapy remains poor. The expression of epidermal growth factor receptor (EGFR) has been established in children with HGGs. This report demonstrated the outcomes of adjuvant nimotuzumab, an EGFR inhibitor, with irinotecan in pediatric HGGs.

METHODS

Children with newly diagnosed HGGs were enrolled. Two weeks after surgery, nimotuzumab with a dose of 150 mg/m² was given every week during radiation. After completion of radiation, a 4-week cycle of nimotuzumab (150 mg/m²) at week 1 and 3 and irinotecan (125 mg/m²) at week 1, 2, and 3 was given.

RESULTS

Sixteen patients (5 females, 11 males), with a mean ± SD age of 8.2 ± 3.5 years were included. Tumors were located at the supratentorial region (50.0%), infratentorial region (43.8%), and both locations (6.2%). The 5-year PFS and OS were 19.9 ± 11.6 and 31.5 ± 13.0%, respectively. Median times of PFS and OS were 1.8 and 1.9 years, respectively. Prognostic factors related to good outcome were the location of tumor at the supratentorial region or outside brainstem and the extension of surgery. Side effects were minimal, with grade 1 anemia in three patients and diarrhea in one patient. Although, the adjuvant regimen of nimotuzumab and irinotecan slightly increases the overall outcome when compared to the historical study, the advantages of this protocol were minimal side effect, short period of hospitalization, and improved OS in patients who received extensive surgery.

Bevacizumab combined with chemotherapy for glioblastoma: a meta-analysis of randomized controlled trials

Bevacizumab, as antibodies, were applied to inhibit tumor angiogenesis by preventing activation of vascular endothelial growth factor receptor. We analyzed four clinical trials, including 607 patients, to investigate the efficacy and safety of bevacizumab when combined with chemotherapy for the treatment of glioblastomas. Results demonstrated that bevacizumab when combined with chemotherapy improved progression-free survival (HR = 0.66; 95% CI 0.56-0.78; p < 0.00001) compared with bevacizumab or chemotherapy alone. Furthermore, overall survival showed insignificant difference between two arms (HR 0.99; 95% CI 0.8-1.21; p = 0.92). However, we found that patients treated with bevacizumab-containing therapy reported increased objective response rate (OR 1.85, 95% CI 1.17-2.93; p = 0.009), but more treatment-related adverse events (OR 1.75; 95% CI 1.09-2.83; p = 0.02).

Modified Criteria for Radiographic Response Assessment in Glioblastoma Clinical Trials

Radiographic endpoints including response and progression are important for the evaluation of new glioblastoma therapies. The current RANO criteria was developed to overcome many of the challenges identified with previous guidelines for response assessment, however, significant challenges and limitations remain. The current recommendations build on the strengths of the current RANO criteria, while addressing many of these limitations. Modifications to the current RANO criteria include suggestions for volumetric response evaluation, use contrast enhanced T1 subtraction maps to increase lesion conspicuity, removal of qualitative non-enhancing tumor assessment requirements, use of the post-radiation time point as the baseline for newly diagnosed glioblastoma response assessment, and "treatment-agnostic" response assessment rubrics for identifying pseudoprogression, pseudoresponse, and a confirmed durable response in newly diagnosed and recurrent glioblastoma trials.

Treatment options for recurrent high-grade gliomas

High-grade gliomas are aggressive brain tumors encompassing Grade III and IV classifications. Of these, glioblastoma (GB) is the most malignant with a high rate of recurrence after initial resection. Although standard treatment does exist for newly diagnosed GBs, therapeutic strategies for recurrent GB are less solidified. However, mounting evidence describes the role of re-resection, bevacizumab, chemotherapy, targeted molecular therapies, immunotherapeutic approaches and radiotherapy in recurrent GB management. This review article provides analysis of the aforementioned therapies, through assessing their effect on overall survival. Because GB tumor heterogeneity is prevalent there is a constant need to investigate therapies targeting recurrence. Studies evaluating both therapeutic targets and strategies for high-grade gliomas are and will remain invaluable.

Dendritic cell immunotherapy versus bevacizumab plus irinotecan in recurrent malignant glioma patients: a survival gain analysis

Background

The bevacizumab and irinotecan protocol is considered a standard treatment regimen for recurrent malignant glioma. Recent advances in immunotherapy have hinted that vaccination with dendritic cells could become an alternative salvage therapy for the treatment of recurrent malignant glioma.

Methods

A search was performed on PubMed, Cochrane Library, Web of Science, ScienceDirect, and Embase in order to identify studies with patients receiving bevacizumab plus irinotecan or dendritic cell therapy for recurrent malignant gliomas. The data obtained from these studies were used to perform a systematic review and survival gain analysis.

Results

Fourteen clinical studies with patients receiving either bevacizumab plus irinotecan or dendritic cell vaccination were identified. Seven studies followed patients that received bevacizumab plus irinotecan (302 patients) and seven studies included patients that received dendritic cell immunotherapy (80 patients). For the patients who received bevacizumab plus irinotecan, the mean reported median overall survival was 7.5 (95% confidence interval [CI] 4.84–10.16) months. For the patients who received dendritic cell immunotherapy, the mean reported median overall survival was 17.9 (95% CI 11.34–24.46) months. For irinotecan + bevacizumab group, the mean survival gain was −0.02±2.00, while that for the dendritic cell immunotherapy group was −0.01±4.54.

Conclusion

For patients with recurrent malignant gliomas, dendritic cell immunotherapy treatment does not have a significantly different effect when compared with bevacizumab and irinotecan in terms of survival gain (P=0.535) and does not improve weighted survival gain (P=0.620).

Blood-brain barrier, cytotoxic chemotherapies and glioblastoma

INTRODUCTION

Glioblastomas (GBM) are the most common and aggressive primary malignant brain tumors in adults. The blood brain barrier (BBB) is a major limitation reducing efficacy of anti-cancer drugs in the treatment of GBM patients. Areas covered: Virtually all GBM recur after the first-line treatment, at least partly, due to invasive tumor cells protected from chemotherapeutic agents by the intact BBB in the brain adjacent to tumor. The passage through the BBB, taken by antitumor drugs, is poorly and heterogeneously documented in the literature. In this review, we have focused our attention on: (i) the BBB, (ii) the passage of chemotherapeutic agents across the BBB and (iii) the strategies investigated to overcome this barrier. Expert commentary: A better preclinical knowledge of the crossing of the BBB by antitumor drugs will allow optimizing their clinical development, alone or combined with BBB bypassing strategies, towards an increased success rate of clinical trials.

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

Purpose

In patients with newly diagnosed glioblastoma that harbors a nonmethylated O6-methylguanine–DNA methyltransferase promotor, standard temozolomide (TMZ) has, at best, limited efficacy. The GLARIUS trial thus explored bevacizumab plus irinotecan (BEV+IRI) as an alternative to TMZ.

Patients and Methods

In this phase II, unblinded trial 182 patients in 22 centers were randomly assigned 2:1 to BEV (10 mg/kg every 2 weeks) during radiotherapy (RT) followed by maintenance BEV (10 mg/kg every 2 weeks) plus IRI(125 mg/m2 every 2 weeks) or to daily TMZ (75 mg/m2) during RT followed by six courses of TMZ (150-200 mg/m2/d for 5 days every 4 weeks). The primary end point was the progression-free survival rate after 6 months (PFS-6).

Results

In the modified intention-to-treat (ITT) population, PFS-6 was increased from 42.6% with TMZ (95% CI, 29.4% to 55.8%) to 79.3% with BEV+IRI (95% CI, 71.9% to 86.7%; P <.001). PFS was prolonged from a median of 5.99 months (95% CI, 2.7 to 7.3 months) to 9.7 months (95% CI, 8.7 to 10.8 months; P < .001). At progression, crossover BEV therapy was given to 81.8% of all patients who received any sort of second-line therapy in the TMZ arm. Overall survival (OS) was not different in the two arms: the median OS was 16.6 months (95% CI, 15.4 to 18.4 months) with BEV+IRI and was 17.5 months (95% CI, 15.1 to 20.5 months) with TMZ. The time course of quality of life (QOL) in six selected domains of the European Organisation for Research and Treatment of Cancer Quality-of-Life Questionnaire (QLQ) –C30 and QLQ-BN20 (which included cognitive functioning), of the Karnofsky performance score, and of the Mini Mental State Examination score was not different between the treatment arms.

Conclusion

BEV+IRI resulted in a superior PFS-6 rate and median PFS compared with TMZ. However, BEV+IRI did not improve OS, potentially because of the high crossover rate. BEV+IRI did not alter QOL compared with TMZ.

Clinical Impact of Bevacizumab in Patients with Relapsed Glioblastoma: Focus on a Real-Life Monocentric SurVey (SV1 Study)

OBJECTIVES

Glioblastoma is one of the most frequent primitive brain tumors. Patients who experience tumor relapse after surgery and concomitant radiochemotherapy have a dismal prognosis. The objective of this study is to analyze efficacy data in terms of overall survival (OS) and progression- free survival (PFS) following combination therapy with bevacizumab (BVZ) and irinotecan among patients with relapsed glioblastoma. Safety data will also be reviewed and all results will be compared with data of the literature.

METHODS

In this single-center retrospective study, all records of patients treated with BVZ and irinotecan for a relapsed glioblastoma were analyzed. Each chemotherapy cycle was repeated every 15 days until progression. Magnetic resonance imaging and neurologic examination were repeated every 6 weeks during treatment.

RESULTS

Forty-five patients were analyzed. The median number of BVZ-irinotecan cycles was 8 (range 1-38). Median PFS was 26 weeks and median OS was 28 weeks. Eighteen of the 45 patients (40% of cases) had an objective response 6 months after initiation of treatment. Two patients had to discontinue treatment due to toxicity.

CONCLUSIONS

The results of the SV1 study are consistent with those found in phase II studies evaluating the same treatment. The irinotecan-BVZ combination is effective in relapsed glioblastoma with acceptable toxicity. Biomarkers predictive of response to BVZ should help in the selection of patients who could benefit from treatment.

NKTR-102 Efficacy versus irinotecan in a mouse model of brain metastases of breast cancer

Background

Brain metastases are an increasing problem in women with invasive breast cancer. Strategies designed to treat brain metastases of breast cancer, particularly chemotherapeutics such as irinotecan, demonstrate limited efficacy. Conventional irinotecan distributes poorly to brain metastases; therefore, NKTR-102, a PEGylated irinotecan conjugate should enhance irinotecan and its active metabolite SN38 exposure in brain metastases leading to brain tumor cytotoxicity.

Methods

Female nude mice were intracranially or intracardially implanted with human brain seeking breast cancer cells (MDA-MB-231Br) and dosed with irinotecan or NKTR-102 to determine plasma and tumor pharmacokinetics of irinotecan and SN38. Tumor burden and survival were evaluated in mice treated with vehicle, irinotecan (50 mg/kg), or NKTR-102 low and high doses (10 mg/kg, 50 mg/kg respectively).

Results

NKTR-102 penetrates the blood-tumor barrier and distributes to brain metastases. NKTR-102 increased and prolonged SN38 exposure (>20 ng/g for 168 h) versus conventional irinotecan (>1 ng/g for 4 h). Treatment with NKTR-102 extended survival time (from 35 days to 74 days) and increased overall survival for NKTR-102 low dose (30 % mice) and NKTR-102 high dose (50 % mice). Tumor burden decreased (37 % with 10 mg/kg NKTR-102 and 96 % with 50 mg/kg) and lesion sizes decreased (33 % with 10 mg/kg NKTR-102 and 83 % with 50 mg/kg NKTR-102) compared to conventional irinotecan treated animals.

Conclusions

Elevated and prolonged tumor SN38 exposure after NKTR-102 administration appears responsible for increased survival in this model of breast cancer brain metastasis. Further, SN38 concentrations observed in this study are clinically achieved with 145 mg/m² NKTR-102, such as those used in the BEACON trial, underlining translational relevance of these results.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1672-4) contains supplementary material, which is available to authorized users.

Seizures and cancer: drug interactions of anticonvulsants with chemotherapeutic agents, tyrosine kinase inhibitors and glucocorticoids

Patients with cancer commonly experience seizures. Combined therapy with anticonvulsant drugs (AEDs) and chemotherapeutic drugs or tyrosine kinase inhibitors carries inherent risks on drug-drug interactions (DDIs). In this review, pharmacokinetic studies of AEDs with chemotherapeutic drugs, tyrosine kinase inhibitors, and glucocorticoids are discussed, including data on maximum tolerated dose, drug clearance, elimination half-life, and organ exposure. Enzyme-inducing AEDs (EIAEDs) cause about a 2-fold to 3-fold faster clearance of concurrent chemotherapeutic drugs metabolized along the same pathway, including cyclophosphamide, irinotecan, paclitaxel, and teniposide, and up to 4-fold faster clearance with the tyrosine kinase inhibitors crizotinib, dasatinib, imatinib, and lapatinib. The use of tyrosine kinase inhibitors, particularly imatinib and crizotinib, may lead to enzyme inhibition of concurrent therapy. Many of the newer generation AEDs do not induce or inhibit drug metabolism, but they can alter enzyme activity by other drugs including AEDs, chemotherapeutics and tyrosine kinase inhibitors. Glucocorticoids can both induce and undergo metabolic change. Quantitative data on changes in drug metabolism help to apply the appropriate dose regimens. Because the large individual variability in metabolic activity increases the risks for undertreatment and/or toxicity, we advocate routine plasma drug monitoring. There are insufficient data available on the effects of tyrosine kinase inhibitors on AED metabolism.

Convection-enhanced delivery of SN-38-loaded polymeric micelles (NK012) enables consistent distribution of SN-38 and is effective against rodent intracranial brain tumor models

Convection-enhanced delivery (CED) of therapeutic agents is a promising local delivery technique that has been extensively studied as a treatment for CNS diseases over the last two decades. One continuing challenge of CED is accurate and consistent delivery of the agents to the target. The present study focused on a new type of therapeutic agent, NK012, a novel SN-38-loaded polymeric micelle. Local delivery profiles of NK012 and SN-38 were studied using rodent brain and intracranial rodent brain tumor models. First, the cytotoxicity of NK012 against glioma cell lines was determined in vitro. Proliferations of glioma cells were significantly reduced after exposure to NK012. Then, the distribution and local toxicity after CED delivery of NK012 and SN-38 were evaluated in vivo. Volume of distribution of NK012 after CED was much larger than that of SN-38. Histological examination revealed minimum brain tissue damage in rat brains after delivery of 40 µg NK012 but severe damage with SN-38 at the same dose. Subsequently, the efficacy of NK012 delivered via CED was tested in 9L and U87MG rodent orthotopic brain tumor models. CED of NK012 displayed excellent efficacy in the 9L and U87MG orthotopic brain tumor models. Furthermore, NK012 and gadolinium diamide were co-delivered via CED to monitor the NK012 distribution using MRI. Volume of NK012 distribution evaluated by histology and MRI showed excellent agreement. CED of NK012 represents an effective treatment option for malignant gliomas. MRI-guided CED of NK012 has potential for clinical application.

Pros and cons of current brain tumor imaging

Over the past 20 years, very few agents have been approved for the treatment of brain tumors. Recent studies have highlighted some of the challenges in assessing activity in novel agents for the treatment of brain tumors. This paper reviews some of the key challenges related to assessment of tumor response to therapy in adult high-grade gliomas and discusses the strengths and limitations of imaging-based endpoints. Although overall survival is considered the "gold standard" endpoint in the field of oncology, progression-free survival and response rate are endpoints that hold great value in neuro-oncology. Particular focus is given to advancements made since the January 2006 Brain Tumor Endpoints Workshop, including the development of Response Assessment in Neuro-Oncology criteria, the value of T2/fluid-attenuated inversion recovery, use of objective response rates and progression-free survival in clinical trials, and the evaluation of pseudoprogression, pseudoresponse, and inflammatory response in radiographic images.

Preclinical impact of bevacizumab on brain and tumor distribution of irinotecan and temozolomide

Glioblastoma (GBM) is the most common primary malignant brain tumour in adults. Prognosis of GBM patients is poor with median overall survival around 15 months. Temozolomide is the chemotherapeutic agent used in the standard of care of newly diagnosed GBM patients relying on radiotherapy with concurrent chemotherapy followed by chemotherapy alone. Irinotecan has shown some efficacy in recurrent malignant gliomas. Bevacizumab has been combined with irinotecan in the treatment of recurrent GBM and with temozolomide in newly diagnosed GBM. As the efficacy of GBM treatments relies on their brain distribution through the blood brain barrier, the aim of the present preclinical work was to study, in in vivo models, the impact of bevacizumab on brain and tumor distribution of temozolomide and irinotecan. Our results show that bevacizumab pre-treatment was associated with a reduced temozolomide brain distribution in tumor-free mice. In tumor bearing mice, bevacizumab increased temozolomide tumor distribution, although not statistically significant. In both tumor-free and tumor-bearing mice, bevacizumab does not modify brain distribution of irinotecan and its metabolite SN-38. Bevacizumab impacts brain distribution of some anti-tumor drugs and potentially their efficacy in GBM. Further studies are warranted to investigate other therapeutic combination.

Bevacizumab for glioblastoma: current indications, surgical implications, and future directions

Initial enthusiasm after promising Phase II trials for treating recurrent glioblastomas with the antiangiogenic drug bevacizumab—a neutralizing antibody targeting vascular endothelial growth factor—was tempered by recent Phase III trials showing no efficacy for treating newly diagnosed glioblastomas. As a result, there is uncertainty about the appropriate indications for the use of bevacizumab in glioblastoma treatment. There are also concerns about the effects of bevacizumab on wound healing that neurosurgeons must be aware of. In addition, biochemical evidence suggests a percentage of tumors treated with bevacizumab for an extended period of time will undergo transformation into a more biologically aggressive and invasive phenotype with a particularly poor prognosis. Despite these concerns, there remain numerous examples of radiological and clinical improvement after bevacizumab treatment, particularly in patients with recurrent glioblastoma with limited therapeutic options. In this paper, the authors review clinical results with bevacizumab for glioblastoma treatment to date, ongoing trials designed to address unanswered questions, current clinical indications based on existing data, neurosurgical implications of bevacizumab use in patients with glioblastoma, the current scientific understanding of the tumor response to short- and long-term bevacizumab treatment, and future studies that will need to be undertaken to enable this treatment to fulfill its therapeutic promise for glioblastoma.

Current and investigational drug strategies for glioblastoma

Medical treatments for glioblastoma face several challenges. Lipophilic alkylators remain the mainstay of treatment, emphasising the primacy of good blood-brain barrier penetration. Temozolomide has emerged as a major contributor to improved patient survival. The roles of procarbazine and vincristine in the procarbazine, lomustine and vincristine (PCV) schedule have attracted scrutiny and several lines of evidence now support the use of lomustine as effective single-agent therapy. Bevacizumab has had a convoluted development history, but clearly now has no major role in first-line treatment, and may even be detrimental to quality of life in this setting. In later disease, clinically meaningful benefits are achievable in some patients, but more impressively the combination of bevacizumab and lomustine shows early promise. Over the last decade, investigational strategies in glioblastoma have largely subscribed to the targeted kinase inhibitor paradigm and have mostly failed. Low prevalence dominant driver lesions such as the FGFR-TACC fusion may represent a niche role for this agent class. Immunological, metabolic and radiosensitising approaches are being pursued and offer more generalised efficacy. Finally, trial design is a crucial consideration. Progress in clinical glioblastoma research would be greatly facilitated by improved methodologies incorporating: (i) routine pharmacokinetic and pharmacodynamic assessments by preoperative dosing; and (ii) multi-stage, multi-arm protocols incorporating new therapy approaches and high-resolution biology in order to guide necessary improvements in science.

Irinotecan and temozolomide brain distribution: a focus on ABCB1

Glioblastoma (GBM), the most common primary brain tumor in adults, is usually rapidly fatal with median survival duration of only 15 months and a 3-year survival rate of <7 %. Temozolomide (TMZ) is the only anticancer drug that has improved survival in GBM when administered with concomitant radiotherapy. Irinotecan (CPT-11) has also shown efficacy in recurrent gliomas monotherapy with moderate response. As the efficacy of GBM treatments relies on their brain distribution through the blood-brain barrier (BBB), the aim of the present work was to study, on an in vivo model, the brain distribution of TMZ, CPT-11 and its active metabolite, SN-38. We have focussed on the role of ABCB1, the main efflux transporter at the BBB level, through pharmacokinetics studies in CF1 mdr1a(+/+) and mdr1a(-/-) mice. Our results show that TMZ, CPT-11 and SN-38 are transported by ABCB1 at the BBB level with brain/plasma ratios of 1.1, 2.1 and 2.3, respectively.

The search for novel therapeutic strategies in the treatment of recurrent glioblastoma multiforme

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor with ≤10% patients surviving 5 years from the time of diagnosis. After tumor progression on frontline therapy with concomitant chemoradiotherapy followed by consolidation temozolomide there are few effective treatment options. Bevacizumab and nitrosureas are the most commonly used systemic options in this instance but no overall survival benefit has been demonstrated. In this review we outline the major avenues of research for treatment of recurrent GBM including anti-angiogenic, signaling pathway blockade and immunotherapy approaches. Results of recent trials as well as pertinent ongoing studies are discussed. Enrollment of patients to clinical trials as well as incorporation of correlative translational science studies to identify predictive biomarkers of treatment response will be key to improving outcomes in this devastating disease.