Treatment of recurrent high-grade gliomas

Psidium guajava induces cytotoxicity in human malignant glioblastoma cell line: Role of reactive oxygen species

One of the deadliest types of CNS primary brain cancers is glioblastoma multiforme (GBM), and the survival rate of patients is about 7.2%. The standard treatment for GBM is surgical interventions followed by temozolomide. We investigated for the first time, the cytotoxic impacts of Psidium guajava (P. guajava) on the U87 GBM cell line. We measured cell toxicity through the MTT test following 24 h, 48 h, and 72 h treatment with different concentrations of fruit and seed hydroalcoholic extracts of P. guajava (25-400 μg/ml). Lipid peroxidation assay, reactive oxygen species (ROS) production, and apoptosis rate were evaluated 24 h after treatment by extracts of P. guajava. Moreover, to determine the Bax/Bcl-2 and NF-κB genes expression, we performed a real-time polymerase chain reaction (RT-PCR). Our finding demonstrated that 50-400 μg/ml of P. guajava extracts dose-dependently decreased the viability of U87 cells. Also, treatment by extracts increased lipid peroxidation, ROS production, and apoptosis in a dose-dependent manner. Moreover, the RT-PCR demonstrated an up-regulation in Bax\Bcl-2 and NF-κB. Thus, P. guajava inhibited the proliferation of U87 GBM cells and increased apoptosis probably through Bax/Bcl-2 and NF-κB regulation.

Targeting the Urotensin II/UT G Protein-Coupled Receptor to Counteract Angiogenesis and Mesenchymal Hypoxia/Necrosis in Glioblastoma

Glioblastomas (GBMs) are the most common primary brain tumors characterized by strong invasiveness and angiogenesis. GBM cells and microenvironment secrete angiogenic factors and also express chemoattractant G protein-coupled receptors (GPCRs) to their advantage. We investigated the role of the vasoactive peptide urotensin II (UII) and its receptor UT on GBM angiogenesis and tested potential ligand/therapeutic options based on this system. On glioma patient samples, the expression of UII and UT increased with the grade with marked expression in the vascular and peri-necrotic mesenchymal hypoxic areas being correlated with vascular density. In vitro human UII stimulated human endothelial HUV-EC-C and hCMEC/D3 cell motility and tubulogenesis. In mouse-transplanted Matrigel sponges, mouse (mUII) and human UII markedly stimulated invasion by macrophages, endothelial, and smooth muscle cells. In U87 GBM xenografts expressing UII and UT in the glial and vascular compartments, UII accelerated tumor development, favored hypoxia and necrosis associated with increased proliferation (Ki67), and induced metalloproteinase (MMP)-2 and -9 expression in Nude mice. UII also promoted a “tortuous” vascular collagen-IV expressing network and integrin expression mainly in the vascular compartment. GBM angiogenesis and integrin αvβ3 were confirmed by in vivo^99mTc-RGD tracer imaging and tumoral capture in the non-necrotic area of U87 xenografts in Nude mice. Peptide analogs of UII and UT antagonist were also tested as potential tumor repressor. Urotensin II-related peptide URP inhibited angiogenesis in vitro and failed to attract vascular and inflammatory components in Matrigel in vivo. Interestingly, the UT antagonist/biased ligand urantide and the non-peptide UT antagonist palosuran prevented UII-induced tubulogenesis in vitro and significantly delayed tumor growth in vivo. Urantide drastically prevented endogenous and UII-induced GBM angiogenesis, MMP, and integrin activations, associated with GBM tumoral growth. These findings show that UII induces GBM aggressiveness with necrosis and angiogenesis through integrin activation, a mesenchymal behavior that can be targeted by UT biased ligands/antagonists.

TRP Channels in Brain Tumors

Malignant glioma including glioblastoma (GBM) is the most common group of primary brain tumors. Despite standard optimized treatment consisting of extensive resection followed by radiotherapy/concomitant and adjuvant therapy, GBM remains one of the most aggressive human cancers. GBM is a typical example of intra-heterogeneity modeled by different micro-environmental situations, one of the main causes of resistance to conventional treatments. The resistance to treatment is associated with angiogenesis, hypoxic and necrotic tumor areas while heterogeneity would accumulate during glioma cell invasion, supporting recurrence. These complex mechanisms require a focus on potential new molecular actors to consider new treatment options for gliomas. Among emerging and underexplored targets, transient receptor potential (TRP) channels belonging to a superfamily of non-selective cation channels which play critical roles in the responses to a number of external stimuli from the external environment were found to be related to cancer development, including glioma. Here, we discuss the potential as biological markers of diagnosis and prognosis of TRPC6, TRPM8, TRPV4, or TRPV1/V2 being associated with glioma patient overall survival. TRPs-inducing common or distinct mechanisms associated with their Ca²⁺-channel permeability and/or kinase function were detailed as involving miRNA or secondary effector signaling cascades in turn controlling proliferation, cell cycle, apoptotic pathways, DNA repair, resistance to treatment as well as migration/invasion. These recent observations of the key role played by TRPs such as TRPC6 in GBM growth and invasiveness, TRPV2 in proliferation and glioma-stem cell differentiation and TRPM2 as channel carriers of cytotoxic chemotherapy within glioma cells, should offer new directions for innovation in treatment strategies of high-grade glioma as GBM to overcome high resistance and recurrence.

The prognosis for patients with newly diagnosed glioblastoma receiving bevacizumab combination therapy: a meta-analysis

Background

A combination of temozolomide (TMZ) and radiotherapy and subsequent adjuvant chemotherapy is the gold standard of treatment for glioblastoma (GB). Bevacizumab (BEV), a humanized monoclonal antibody that blocks the effects of vascular endothelial growth factor A, has produced impressive response rates for recurrent GB and has been approved as second-line therapy. The efficacy and safety of BEV in newly diagnosed GB are not known.

Aim

This systematic meta-analysis was undertaken to evaluate the value of combination therapy involving BEV in newly diagnosed GB.

Methods

Electronic databases were searched for eligible literature up to October 2017. Randomized controlled trials assessing the efficacy and safety of BEV in patients with newly diagnosed GB were included, of which the main outcomes were progression-free survival (PFS), overall survival (OS), and adverse events (AEs). All the data were pooled with the corresponding 95% confidence intervals (CIs) using RevMan software. Sensitivity analyses and heterogeneity were quantitatively evaluated.

Results

A total of six randomized controlled trials were included in this analysis. The experimental BEV group had significantly improved the overall PFS (OR =0.46, 95% CI =0.26–0.81, P=0.007), as well as PFS at 6 months (OR =3.47, 95% CI =2.85–4.22, P<0.00001) and PFS at 12 months (OR =2.02, 95% CI =1.66–2.46, P<0.00001), respectively. However, there were no significant differences in PFS at 24 months with BEV (OR =0.95, 95% CI =0.61–1.48, P=0.82). OS at 6 months (P=0.07) and 24 months (P=0.07) was not significantly improved with BEV in patients with newly diagnosed GB. However, the meta-analysis on the OS at 12 months showed differences with BEV (OR =1.24, 95% CI =1.03–1.50, P=0.02).

Conclusion

Our study indicates that addition of BEV for newly diagnosed GB resulted in a superior PFS rate. However, the combination therapy involving BEV did not improve OS. Future investigations are needed to analyze whether BEV helps improve OS efficacy.

AG488 as a therapy against gliomas

High-grade gliomas such as glioblastomas (GBM) present a deadly prognosis following diagnosis and very few effective treatment options. Here, we investigate if the small molecule AG488 can be an effective therapy against GBM with both anti-angiogenic as well as an anti-microtubule inhibiting modalities, using a human G55 glioma xenograft model in nude mice. From in vitro studies, we report that AG488 incubation reduced cell viability in G55 and HMEC-1 cells more so than TMZ treatment, and AG488 treatment also decreased cell viability in normal astrocytes, but not as much as for G55 cells (p<0.0001). In vivo investigations indicated that AG488 therapy helped reduce tumor volumes (p<0.0001), prolong survival (p<0.01), increase tumor perfusion (p<0.01), and decrease microvessel density (MVD) (p<0.05), compared to untreated mice or mice treated with non-specific IgG, in the G55 xenograft model. Additionally, AG488 did not induce apoptosis in normal mouse brain tissue. Animal survival and tumor volume changes for AG488 were comparable to TMZ or anti-VEGF therapies, however AG488 was found to be more effective in decreasing tumor-related vascularity (perfusion and MVD). AG488 is a potential novel therapy against high-grade gliomas.

CNS Anticancer Drug Discovery and Development Conference White Paper

Following the first CNS Anticancer Drug Discovery and Development Conference, the speakers from the first 4 sessions and organizers of the conference created this White Paper hoping to stimulate more and better CNS anticancer drug discovery and development. The first part of the White Paper reviews, comments, and, in some cases, expands on the 4 session areas critical to new drug development: pharmacological challenges, recent drug approaches, drug targets and discovery, and clinical paths. Following this concise review of the science and clinical aspects of new CNS anticancer drug discovery and development, we discuss, under the rubric "Accelerating Drug Discovery and Development for Brain Tumors," further reasons why the pharmaceutical industry and academia have failed to develop new anticancer drugs for CNS malignancies and what it will take to change the current status quo and develop the drugs so desperately needed by our patients with malignant CNS tumors. While this White Paper is not a formal roadmap to that end, it should be an educational guide to clinicians and scientists to help move a stagnant field forward.

Anticancer activity of taraxerol acetate in human glioblastoma cells and a mouse xenograft model via induction of autophagy and apoptotic cell death, cell cycle arrest and inhibition of cell migration

The aim of the present study was to investigate the in vitro and in vivo anticancer and apoptotic effects of taraxerol acetate in U87 human glioblastoma cells. The effects on cell cycle phase distribution, cell cycle-associated proteins, autophagy, DNA fragmentation and cell migration were assessed. Cell viability was determined using the MTT assay, and phase contrast and fluorescence microscopy was utilized to determine the viability and apoptotic morphological features of the U87 cells. Flow cytometry using propidium iodide and Annexin V-fluorescein isothiocyanate demonstrated the effect of taraxerol acetate on the cell cycle phase distribution and apoptosis induction. Western blot analysis was performed to investigate the effect of the taraxerol acetate on cell cycle-associated proteins and autophagy-linked LC3B-II proteins. The results demonstrated that taraxerol acetate induced dose- and time-dependent cytotoxic effects in the U87 cells. Apoptotic induction following taraxerol acetate treatment was observed and the percentage of apoptotic cells increased from 7.3% in the control cells, to 16.1, 44.1 and 76.7% in the 10, 50 and 150 µM taraxerol acetate-treated cells, respectively. Furthermore, taraxerol acetate treatment led to sub-G₁ cell cycle arrest with a corresponding decrease in the number of S-phase cells. DNA fragments were observed as a result of the gel electrophoresis experiment following taraxerol acetate treatment. To investigate the inhibitory effects of taraxerol acetate on the migration of U87 cell, a wound healing assay was conducted. The number of cells that migrated to the scratched area decreased significantly following treatment with taraxerol acetate. In addition, taraxerol acetate inhibited tumor growth in a mouse xenograft model. Administration of 0.25 and 0.75 µg/g taraxerol acetate reduced the tumor weight from 1.2 g in the phosphate-buffered saline (PBS)-treated group (control) to 0.81 and 0.42 g, respectively. Similarly, 0.25 and 0.75 µg/g taraxerol acetate injection reduced the tumor volume from 1.3 cm³ in the PBS-treated group (control) to 0.67 and 0.25 cm³, respectively.

Can bevacizumab prolong survival for glioblastoma patients through multiple lines of therapy?

Glioblastoma has a poor prognosis accompanied by debilitating neurological symptoms and impaired quality of life. Effective treatment strategies are needed, beyond the current standard of care (SOC), to improve outcomes. Glioblastomas are highly vascularized with elevated levels of VEGF, representing an appropriate target for selective therapies. The role of the anti-VEGF agent bevacizumab in newly diagnosed and recurrent glioblastoma is not fully clear at this time. Although bevacizumab has demonstrated improvements in progression-free survival in newly diagnosed and recurrent glioblastoma, there remain challenges in assessing disease progression after antiangiogenic treatment. The bevacizumab mechanism of action suggests a rationale for continuing bevacizumab treatment through multiple lines of therapy, strengthened by longer progression-free and overall survival observed with bevacizumab continuation beyond progression in a Phase III study in metastatic colorectal cancer and in pooled analyses of Phase II trials in glioblastoma. A novel study (randomized, double-blind, Phase IIIb; TAMIGA [MO28347]) aims to evaluate whether continuing bevacizumab plus lomustine (as second-line therapy) and SOC (third line and beyond) improves survival compared with placebo plus lomustine and then placebo plus SOC in patients with glioblastoma who progressed after first-line bevacizumab plus SOC.

Hedyotis diffusa Willd extract inhibits the growth of human glioblastoma cells by inducing mitochondrial apoptosis via AKT/ERK pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Hedyotis diffusa Willd (Rubiaceae) (HDW) has been widely applied for the treatment of tumors, inflammation and toxication in traditional Chinese medicine. The antitumor effect of HDW on glioblastoma has been rarely reported. We aim to evaluate the activity of this extract and explore the underlying mechanism in U87 human glioblastoma cell line.

MATERIALS AND METHODS

Cytotoxicity of HDW extract on U87 cells was measured by MTT assay. Apoptosis, cell cycle arrest and mitochondrial membrane potential (MMP) collapse induced by HDW extract were determined by flow cytometry. Caspase activity was analyzed based on colorimetric assay with a microplate spectrophotometer. Protein expression was examined by Western blot.

RESULTS

HDW extract suppressed U87 cells growth in a dose- and time-dependent manner. Flow cytometry showed that HDW extract induced significant apoptosis, S/G2-M phase arrest and MMP collapse in U87 cells. Furthermore, dose-dependent activation of caspase-3, Bcl-2, Bax and ERK was observed with HDW extract treatment. Decreased Bcl-2/Bax ratio and Akt suppression were readily found as well.

CONCLUSIONS

Induction of mitochondria-mediated apoptosis played an essential role in antitumor activity of HDW extract in U87 cells, in which ERKs and Akt signaling proteins were also involved. These findings contributed to the feasibility of using HDW extract in glioblastoma treatment and the understanding of the molecular mechanism.

Impact of health-related quality of life and fatigue on survival of recurrent high-grade glioma patients

Quality of life (QoL) impairment and fatigue are frequently experienced during treatment for recurrent high-grade glioma (HGG). Fatigue and QoL impairments can be due to primary neurological dysfunction, cytotoxic treatments, mood disturbances, and supportive medications. We now seek to understand how QoL and fatigue impacts survival in recurrent HGG. Using a prospective observational design, 237 patients with recurrent HGG and KPS ≥70 completed a self-administered questionnaire that evaluated QoL and fatigue. QoL was assessed with Functional Assessment of Cancer Therapy-General (FACT-G) and FACT-Brain (FACT-Br) scales while fatigue was assessed using Functional Assessment of Chronic Illness Therapy (FACIT-F) scale. Cox proportional hazard models were utilized to evaluate the association between QoL and fatigue and survival. Seventy-three (31 %) subjects had recurrent WHO grade III gliomas and 164 (69 %) had recurrent WHO grade IV gliomas. Median follow-up analysis was 27.60 months. In univariate Cox analyses, the FACT-Br specific subscale (HR 0.88; CI 95 %, 0.77-1; p = 0.048) and FACIT-F (HR 0.82; CI 95 %, 0.68-0.99; p = 0.045) were both significant predictors of survival. Fatigue added prognostic information beyond that provided by KPS, age, sex, tumor grade, and number of prior progressions (HR 0.80; CI 95 %, 0.68-0.9; p = 0.031). A greater degree of fatigue was associated with poorer survival in recurrent HGG patients. In multivariable analyses, FACT-G and FACT-Br are not independent predictors of prognosis. Fatigue is a strong independent predictor of survival that provides incremental prognostic value to the traditional markers of prognosis in recurrent HGG. Pharmacological or non-pharmacological strategies to treat fatigue warrant investigation.

Impact of meriolins, a new class of cyclin-dependent kinase inhibitors, on malignant glioma proliferation and neo-angiogenesis

BACKGROUND

Glioblastomas are the most frequent and most aggressive primary brain tumors in adults. The median overall survival is limited to a few months despite surgery, radiotherapy, and chemotherapy. It is now clearly established that hyperactivity of cyclin-dependent kinases (CDKs) is one of the processes underlying hyperproliferation and tumoral growth. The marine natural products meridianins and variolins, characterized as CDK inhibitors, display a kinase-inhibitory activity associated with cytotoxic effects. In order to improve selectivity and efficiency of these CDK inhibitors, a series of hybrid compounds called meriolins have been synthesized.

METHODS

The potential antitumoral activity of meriolins was investigated in vitro on glioma cell lines (SW1088 and U87), native neural cells, and a human endothelial cell line (HUV-EC-C). The impact of intraperitoneal or intratumoral administrations of meriolin 15 was evaluated in vivo on 2 different nude mice-xenografted glioma models.

RESULTS

Meriolins 3, 5, and 15 exhibited antiproliferative properties with nanomolar IC50 and induced cell-cycle arrest and CDK inhibition associated with apoptotic events in human glioma cell lines. These meriolins blocked the proliferation rate of HUV-EC-C through cell cycle arrest and apoptosis. In vivo, meriolin 15 provoked a robust reduction in tumor volume in spite of toxicity for highest doses, associated with inhibition of cell division, activation of caspase 3, reduction of CD133 cells, and modifications of the vascular architecture.

CONCLUSION

Meriolins, and meriolin 15 in particular, exhibit antiproliferative and proapoptotic activities on both glioma and intratumoral endothelial cells, constituting key promising therapeutic lead compounds for the treatment of glioblastoma.

BMP4, a new prognostic factor for glioma

BACKGROUND

The expression status of bone morphogenetic protein 4 (BMP4) in gliomas is still unclear by now. We try to investigate the relationship between BMP4 expression and the biological behavior of gliomas in order to lay a foundation for the management of these tumors.

METHODS

A total of 630 patients with glioma were enrolled in the study from January 2002 to January 2008. The expression status of BMP4 in gliomas was evaluated by RT-PCR and immunohistochemistry. The relationships between BMP4 expression and clinicopathological parameters and between BMP4 expression and prognosis were also studied.

RESULTS

The expression of BMP4 in tumor tissues was significantly lower than that in the paracancer tissues at both mRNA and protein levels (P = 0.01 and 0.001, respectively). Univariate analysis showed that BMP4 expression was closely related to extent of resection, Ki-67 expression, and the WHO grade (P = 0.001, 0.001, and 0.001, respectively), but it was not related to age, sex, or the Karnofsky Performance Status (KPS) score (P = 0.099, 0.472, and 0.201, respectively). Finally, Ki-67 expression and the WHO grade were found to be related to BMP4 expression using logistic regression (P = 0.001 and 0.001, respectively). Interestingly, we found that the expression of BMP4 was significantly related to distant glioma metastasis. Cox regression analysis identified the KPS score, extent of resection, Ki-67 expression, WHO grade, and BMP4 expression as independent prognostic factors (P = 0.044, 0.010, 0.002, 0.001, and 0.001, respectively).

CONCLUSIONS

BMP4 is differentially expressed in glioma patients and is closely related to the biological behavior of gliomas. BMP4 expression was found to be a strong predictor of distant metastasis and postoperative prognosis.

Bevacizumab-based therapy in relapsed glioblastoma: rationale and clinical experience to date

Relapsed glioblastoma (GBM) has an extremely poor prognosis and remains an invariably fatal disease, with a median overall survival of 6-7 months. Despite numerous clinical trials over the past 20-30 years, treatment options for relapsed GBM remain limited. In recent years, significant research efforts have focused on the use of antiangiogenic therapies for the treatment of GBM. Bevacizumab is a humanized monoclonal antibody that specifically inhibits the proangiogenic VEGF, with well-established clinical efficacy in a number of solid malignancies, which is now under investigation for the treatment of GBM. In this review, we discuss the available data regarding bevacizumab-based therapy in relapsed GBM, highlighting its potential and ongoing challenges in this difficult-to-treat disease.

Active efflux of Dasatinib from the brain limits efficacy against murine glioblastoma: broad implications for the clinical use of molecularly targeted agents

The importance of the blood-brain barrier in preventing effective pharmacotherapy of glioblastoma has been controversial. The controversy stems from the fact that vascular endothelial cell tight junctions are disrupted in the tumor, allowing some systemic drug delivery. P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) efflux drugs from brain capillary endothelial cells into the blood. We tested the hypothesis that although the tight junctions are "leaky" in the core of glioblastomas, active efflux limits drug delivery to tumor-infiltrated normal brain and consequently, treatment efficacy. Malignant gliomas were induced by oncogene transfer into wild-type (WT) mice or mice deficient for Pgp and BCRP (knockout, KO). Glioma-bearing mice were orally dosed with dasatinib, a kinase inhibitor and dual BCRP/PgP substrate that is being currently tested in clinical trials. KO mice treated with dasatinib survived for twice as long as WT mice. Microdissection of the tumor core, invasive rim, and normal brain revealed 2- to 3-fold enhancement in dasatinib brain concentrations in KO mice relative to WT. Analysis of signaling showed that poor drug delivery correlated with the lack of inhibition of a dasatinib target, especially in normal brain. A majority of human glioma xenograft lines tested expressed BCRP or PgP and were sensitized to dasatinib by a dual BCRP/Pgp inhibitor, illustrating a second barrier to drug delivery intrinsic to the tumor itself. These data show that active efflux is a relevant obstacle to treating glioblastoma and provide a plausible mechanistic basis for the clinical failure of numerous drugs that are BCRP/Pgp substrates.

Recurrent high-grade glioma

OPINION STATEMENT

Opinions vary on the best treatment options for recurrent high-grade glioma. Some argue that bevacizumab should become standard of care for patients with recurrent glioblastoma, especially in light of recent FDA approval for this indication. However, this opinion is not uniformly accepted. Age, performance status, histology, tumor size and location, O6-methylguanine-DNA methyltransferase (MGMT) methylation status for glioblastoma, 1p/19q status for oligodendroglial tumors, and the number and types of prior therapies are important considerations. In addition, recurrent disease must be distinguished from "pseudoprogression" due to treatment effects. Enrollment in a clinical trial is the optimal choice for most patients with recurrent high-grade glioma after failure of radiation therapy and temozolomide. For patients who are ineligible or do not have access to clinical trials, then either bevacizumab monotherapy or bevacizumab in combination with a second agent such as irinotecan is recommended. Involved-field external beam radiation should be considered for patients with anaplastic gliomas who have not received radiation. For patients with anaplastic astrocytoma who progress after radiotherapy, temozolomide may be used. For patients with anaplastic oligodendroglioma who progress after radiotherapy, PCV chemotherapy and temozolomide are options. Oligodendroglial tumors with 1p/19q deletions are more likely to respond to treatment. In the past, carmustine was commonly used to treat recurrent high-grade glioma, but the utility of carmustine in the modern era is unknown because most studies were performed prior to the widespread use of temozolomide. High-precision re-irradiation such as stereotactic radiosurgery is another option in high-grade glioma, especially for patients with poor bone marrow reserve or inability to tolerate chemotherapy, but there is a paucity of studies with adequate controls. Surgery may be useful as adjuvant treatment for patients with symptoms due to mass effect or for patients requiring definitive histopathology, but it generally should be combined with another treatment modality. Emerging therapies, including dose-intense temozolomide regimens, targeted molecular inhibitors, other antiangiogenic therapies, viral gene therapies, immunotherapies, and convection-enhanced delivery of targeted immunotoxins, are still under investigation.

Should we reoperate for recurrent high-grade astrocytoma?

Despite optimal treatment of post-operative radiotherapy and chemotherapy for newly diagnosed high-grade astrocytoma, nearly all patients eventually recur. However, the efficacy of reoperation for recurrent astrocytoma is still debatable as to different surgical indications. To investigate the therapeutic effect of reoperation on patients with recurrent high-grade astrocytoma more objectively, a retrospective case-matched study was carried out. The clinical data of 63 cases of recurrent high-grade astrocytoma treated between January 2006 and December 2008 were studied. A total of 21 cases received reoperation immediately after tumor recurrence, while 42 cases without reoperation were matched by gender, age, Karnofsky Performance Scale (KPS) score, histopathology, recurrent interval after the first operation, extent of initial surgery, adjuvant treatment and characteristics of recurrent tumor. The study showed that the median survival time was 7 months in the reoperation group, while in non-reoperation group, it was 4 months. There was significant difference on univariate analysis (P < 0.001). Moreover, the median duration time of progression-free survival (PFS) after tumor recurrence was significantly (P < 0.001) longer in the reoperation group (5 months) than that in the non-reoperation group (2.5 months). The prognostic factors of recurrent high-grade astrocytoma included reoperation, KPS score and tumor location. It was indicated that reoperation could prolong the survival time and improve the quality of survival in patients of recurrent high-grade astrocytoma.

Delivery of molecularly targeted therapy to malignant glioma, a disease of the whole brain

Glioblastoma multiforme, because of its invasive nature, can be considered a disease of the entire brain. Despite recent advances in surgery, radiotherapy and chemotherapy, current treatment regimens have only a marginal impact on patient survival. A crucial challenge is to deliver drugs effectively to invasive glioma cells residing in a sanctuary within the central nervous system. The blood-brain barrier (BBB) restricts the delivery of many small and large molecules into the brain. Drug delivery to the brain is further restricted by active efflux transporters present at the BBB. Current clinical assessment of drug delivery and hence efficacy is based on the measured drug levels in the bulk tumour mass that is usually removed by surgery. Mounting evidence suggests that the inevitable relapse and lethality of glioblastoma multiforme is due to a failure to effectively treat invasive glioma cells. These invasive cells hide in areas of the brain that are shielded by an intact BBB, where they continue to grow and give rise to the recurrent tumour. Effective delivery of chemotherapeutics to the invasive glioma cells is therefore critical, and long-term efficacy will depend on the ability of a molecularly targeted agent to penetrate an intact and functional BBB throughout the entire brain. This review highlights the various aspects of the BBB, and also the brain-tumour-cell barrier (a barrier due to expression of efflux transporters in tumour cells), that together can significantly influence drug response. It then discusses the challenge of glioma as a disease of the whole brain, which lends emphasis to the need to deliver drugs effectively across the BBB to reach both the central tumour and the invasive glioma cells.

A phase II study evaluating the efficacy and safety of AMG 102 (rilotumumab) in patients with recurrent glioblastoma

This phase II study evaluated the efficacy and safety of AMG 102 (rilotumumab), a fully human monoclonal antibody against hepatocyte growth factor/scatter factor (HGF/SF), in patients with recurrent glioblastoma (GBM). Patients with histologically confirmed, measurable recurrent GBM or gliosarcoma (World Health Organization grade 4) and ≤3 relapses or prior systemic therapies received AMG 102 (10 or 20 mg/kg) by infusion every 2 weeks. The primary endpoint was best confirmed objective response rate (central assessment) per Macdonald criteria. Of the 61 patients who enrolled, 60 received AMG 102. Twenty-nine patients (48%) had previously received bevacizumab. There were no objective responses per central assessment, but 1 patient had an objective response per investigator assessment. Median overall survival (95% CI) in the 10- and 20-mg/kg cohorts was 6.5 months (4.1-9.8) and 5.4 months (3.4-11.4), respectively, and progression-free survival (PFS) per central assessment was 4.1 weeks (4.0-4.1) and 4.3 weeks (4.1-8.1), respectively. PFS was similar among patients who had previously received bevacizumab compared with bevacizumab-naive patients. The most common adverse events were fatigue (38%), headache (33%), and peripheral edema (23%). AMG 102 serum concentrations increased approximately dose-proportionally with 2-fold accumulation at steady state. Plasma total HGF/SF and soluble c-Met concentrations increased 12.05- and 1.12-fold, respectively, from baseline during AMG 102 treatment. AMG 102 monotherapy at doses up to 20 mg/kg was not associated with significant antitumor activity in heavily pretreated patients with recurrent GBM.