Single-agent bevacizumab or lomustine versus a combination of bevacizumab plus lomustine in patients with recurrent glioblastoma (BELOB trial): a randomised controlled phase 2 trial. Lancet Oncol. 2014;15:943-953. [PMID: 25035291 DOI: 10.1016/s1470-2045(14)70314-6]

Prognostic value and kinetics of circulating endothelial cells in patients with recurrent glioblastoma randomised to bevacizumab plus lomustine, bevacizumab single agent or lomustine single agent. A report from the Dutch Neuro-Oncology Group BELOB trial

BACKGROUND

Angiogenesis is crucial for glioblastoma growth, and anti-vascular endothelial growth factor agents are widely used in recurrent glioblastoma patients. The number of circulating endothelial cells (CECs) is a surrogate marker for endothelial damage. We assessed their kinetics and explored their prognostic value in patients with recurrent glioblastoma.

METHODS

In this side study of the BELOB trial, 141 patients with recurrent glioblastoma were randomised to receive single-agent bevacizumab or lomustine, or bevacizumab plus lomustine. Before treatment, after 4 weeks and after 6 weeks of treatment, CECs were enumerated.

RESULTS

The number of CECs increased during treatment with bevacizumab plus lomustine, but not during treatment in the single-agent arms. In patients treated with lomustine single agent, higher absolute CEC numbers after 4 weeks (log₁₀CEC hazard ratio (HR) 0.41, 95% CI 0.18-0.91) and 6 weeks (log₁₀CEC HR 0.16, 95% CI 0.05-0.56) of treatment were associated with improved overall survival (OS). Absolute CEC numbers in patients receiving bevacizumab plus lomustine or bevacizumab single agent were not associated with OS.

CONCLUSION

CEC numbers increased during treatment with bevacizumab plus lomustine but not during treatment with either agent alone, suggesting that this combination induced the greatest vascular damage. Although the absolute number of CECs was not associated with OS in patients treated with bevacizumab either alone or in combination, they could serve as a marker in glioblastoma patients receiving lomustine single agent.

[Personalized therapy for gliomas]

Current therapies for patients with malignant gliomas are starting to integrate molecular factors and age. Nonetheless, these therapies are still not sufficiently individualized. Some positive examples of transfer from basic science to clinical application are currently integrated into the standard treatment and guidelines. These are mainly genetic and other molecular factors that improve diagnosis and classification of gliomas and markers supporting prognostication. Examples for predictive biomarkers are methylation of the O-6-methylguanine-DNA methyltransferase (MGMT) promoter and the codeletion of chromosome arms 1p and 19q (1p/19q codel). The autoactive, truncated form of epidermal growth factor receptor (EGFRvIII) and the R132H mutation of isocitrate dehydrogenase 1 (IDH-1) are used as targets in currently running immunotherapeutic, targeted trials. Integration of functional imaging parameters into the monitoring and development of uniform assessment criteria improve the ability to evaluate therapy response and implement imaging biomarkers to guide therapies. As a result of the current efforts there are better classified prognostic groups and improved survival times with maintained functional and quality of life parameters in some glioma subgroups. Given the current dynamics, an improved, better differentiated classification of brain tumors including molecular parameters as well as more rational precise guiding of therapies with early, uniform response assessment is expected in the near future.

Re-resection for recurrent high-grade glioma in the setting of re-irradiation: more is not always better

The optimal treatment for patients with recurrent high grade glioma (HGG) remains controversial. Available therapies include surgery, re-irradiation, alternating electric fields or systemic therapy. Here we investigate whether re-resection will improve survival in patients receiving repeat radiotherapy for tumor recurrence. 231 consecutive patients with recurrent HGG treated with re-irradiation between 1994 and 2012 were analyzed. 105 patients underwent re-resection. Re-irradiation was delivered using daily fractions of 3.5 Gy to a median total dose of 35 Gy. Survival was then analyzed comparing patients with and without re-resection. Overall survival (OS) and survival from the first recurrence are reported. Univariate and cox-proportional hazard modeling was performed in a step-wise multivariate analysis using known prognostic factors. The median follow-up time from initial diagnosis was 25.7 months. The median OS from initial diagnosis of the entire group was 22.5 months. There was no significant difference in median overall survival between patients who received re-resection versus no re-resection, 23 versus 21.9 months respectively (p = 0.6). Additionally, there was no difference in median survival from the time of first recurrence 10.5 months without re-resection versus 11.1 months with re-resection (p = 0.09). After adjusting for known prognostic variables, only age remained significant. Re-irradiation is an effective salvage therapy for patients with localized, progressive high grade glioma, achieving a median survival of 10-11 months from re-irradiation. Our data reveals no significant improvement in survival with the addition of re-resection to re-irradiated patients with HGG.

[Treatment of the glioma microenvironment]

Therapeutic concepts for malignant gliomas increasingly target the genetically non-transformed tumor stroma rather than the tumor cells themselves. There are two particular compartments of the tumor stroma which are currently tackled: the vascular compartment by using antiangiogenic treatment with the aim of vascular normalization and the immune compartment with the aim of enhancing or inducing anti-tumor immunity. Although the vascular endothelial growth factor (VEGF) A antibody bevacizumab has not been approved for the treatment of malignant glioma in European countries, there is evidence from smaller trials of biological efficacy particularly in recurrent disease and the results of a large European phase III study testing the clinical efficacy are currently expected. Immunotherapies are on the verge of entering the clinical arena with the first randomized phase III clinical trials having already been completed. In these studies, active vaccination and checkpoint inhibitors which are approved for other tumor entities are being tested. This article provides an overview on the current antiangiogenic and immunological therapies for gliomas, summarizes the results of clinical trials and discusses further developments.

Use of bevacizumab in recurrent glioblastoma

Glioblastoma (GBM) is the most common adult primary brain neoplasm. Despite advances in treatment, GBM continues to be associated with considerable morbidity and mortality as compared with other malignancies. Standard treatment for GBM results in survival of 12.9 months (95% CI: 12.3-13.7 months) with a median progression-free survival of 7.2 months (95% CI: 6.4-8.2 months) in a modern GBM cohort. These aggressive tumors recur and treatment for recurrent GBM continues to have very poor outcomes. Prior to the use of bevacizumab, monoclonal antibody to VEGF, 6-month progression-free survival in clinical trials for recurrent GBM ranged from 9 to 15%. Trials utilizing bevacizumab and its subsequent US FDA approval have given more hope to recurrent GBM and this concise review discusses bevacizumab in recurrent GBM. This review focuses on time-to-event outcomes (overall survival, progression-free survival and 6-month progression-free survival) in clinical trials utilizing bevacizumab for the treatment of recurrent GBM. For this review, we have chosen to focus primarily on Phase II clinical trials that have been published and available in the literature (PubMed). While we focused primarily on time-to-event variables, toxicity and safety of bevacizumab is very important and this agent can be associated with serious life-threatening toxicities. We have included a general section of toxicities but for a more lengthy review please see the excellent study by Odia and colleagues.

The impact of bevacizumab on health-related quality of life in patients treated for recurrent glioblastoma: results of the randomised controlled phase 2 BELOB trial

BACKGROUND

The BELOB study, a randomised controlled phase 2 trial comparing lomustine, bevacizumab and combined lomustine and bevacizumab in patients with recurrent glioblastoma, showed that the 9-month overall survival rate was most promising in the combination arm. Here we report the health-related quality of life (HRQoL) results, a secondary trial end-point.

METHODS

HRQoL was measured at baseline and every 6weeks until progression using the European Organisation for Research and Treatment of Cancer (EORTC) core questionnaire (QLQ-C30) and brain module (QLQ-BN20). HRQoL was assessed over time for five preselected scales (global health (GH), physical (PF) and social functioning (SF), motor dysfunction (MD) and communication deficit (CD)). Moreover, mean changes in HRQoL from baseline until progression were determined.

RESULTS

138/148 patients with at least a baseline HRQoL assessment were analysed. Over time, HRQoL remained relatively stable in all treatment arms for all five scales, at least during the first three treatment cycles. More than half (54-61%) of the patients showed stable (<10 point change) or improved (⩾10 point change) HRQoL during their progression-free time, except for SF (43%), irrespective of treatment arm. Deterioration of mean HRQoL was most profound at disease progression for all scales except SF, which deteriorated earlier in disease course. Compared to baseline, 40% of patients had clinically relevant (⩾10 points) worse GH, PF and SF, while 44% and 31% had increased MD and CD at disease progression, irrespective of treatment arm.

CONCLUSIONS

Bevacizumab, whether or not in combination with lomustine, did not negatively affect HRQoL in patients treated for recurrent glioblastoma in this randomised study.

Lessons from anti-vascular endothelial growth factor and anti-vascular endothelial growth factor receptor trials in patients with glioblastoma

Treatment of glioblastoma (GBM), the most common primary malignant brain tumor in adults, remains a significant unmet need in oncology. Historically, cytotoxic treatments provided little durable benefit, and tumors recurred within several months. This has spurred a substantial research effort to establish more effective therapies for both newly diagnosed and recurrent GBM. In this context, antiangiogenic therapy emerged as a promising treatment strategy because GBMs are highly vascular tumors. In particular, GBMs overexpress vascular endothelial growth factor (VEGF), a proangiogenic cytokine. Indeed, many studies have demonstrated promising radiographic response rates, delayed tumor progression, and a relatively safe profile for anti-VEGF agents. However, randomized phase III trials conducted to date have failed to show an overall survival benefit for antiangiogenic agents alone or in combination with chemoradiotherapy. These results indicate that antiangiogenic agents may not be beneficial in unselected populations of patients with GBM. Unfortunately, biomarker development has lagged behind in the process of drug development, and no validated biomarker exists for patient stratification. However, hypothesis-generating data from phase II trials that reveal an association between increased perfusion and/or oxygenation (ie, consequences of vascular normalization) and survival suggest that early imaging biomarkers could help identify the subset of patients who most likely will benefit from anti-VEGF agents. In this article, we discuss the lessons learned from the trials conducted to date and how we could potentially use recent advances in GBM biology and imaging to improve outcomes of patients with GBM who receive antiangiogenic therapy.

Medical management of brain tumors and the sequelae of treatment

Patients with malignant brain tumors are prone to complications that negatively impact their quality of life and sometimes their overall survival as well. Tumors may directly provoke seizures, hypercoagulable states with resultant venous thromboembolism, and mood and cognitive disorders. Antitumor treatments and supportive therapies also produce side effects. In this review, we discuss major aspects of supportive care for patients with malignant brain tumors, with particular attention to management of seizures, venous thromboembolism, corticosteroids and their complications, chemotherapy including bevacizumab, and fatigue, mood, and cognitive dysfunction.

[Chemotherapy of brain tumors in aduts]

The treatment of patients with brain tumors has long been the domain of neurosurgery and radiotherapy but chemotherapy is now well established as an additional treatment option for many tumor entities in neuro-oncology. This is particularly true for patients with newly diagnosed and relapsing glioblastoma and anaplastic glioma as well as the treatment of medulloblastoma and primary lymphoma of the central nervous system (CNS). In addition to purely histopathological features, treatment decisions including those for chemotherapy are now based increasingly more on molecular tumor profiling. Within the group of gliomas these markers include the methylation status of the O-6-methylguanine-DNA methyltransferase (MGMT) promoter and the 1p/19q status, which reflects the loss of genetic material on chromosome arms 1p and 19q. The presence of a 1p/19q codeletion is associated with a better prognosis and increased sensitivity to alkylating chemotherapy in patients with anaplastic gliomas.

Relative cerebral blood volume is a potential predictive imaging biomarker of bevacizumab efficacy in recurrent glioblastoma

BACKGROUND

To analyze the relevance of dynamic susceptibility-weighted contrast-enhanced MRI (DSC-MRI) derived relative cerebral blood volume (rCBV) analysis for predicting response to bevacizumab (BEV) in patients with recurrent glioblastoma (rGB).

METHODS

A total of 127 patients diagnosed with rGB receiving either bevacizumab (71 patients, BEV cohort) or alkylating chemotherapy (56 patients, non-BEV cohort) underwent conventional anatomic MRI and DSC-MRI at baseline and at first follow-up after treatment initiation. The mean rCBV of the contrast-enhancing tumor (cT1) as well as cT1 and fluid-attenuated inversion recovery (FLAIR) volumes at both time points were correlated with progression-free survival (PFS) and overall survival (OS) using Cox proportional hazard models, logistic regression, and the log-rank test.

RESULTS

Baseline rCBV was associated with both PFS (hazard ratio [HR] = 1.3; P < .01) and OS (HR = 1.3; P < .01) in the BEV cohort and predicted 6-month PFS in 82% and 12-month OS in 79% of patients, whereas it was not associated with PFS (HR = 1.0; P = .70) or OS (HR = 1.0; P = .47) in the non-BEV cohort. Corresponding median OS and PFS rates in the BEV cohort for patients with rCBV-values less than 3.92 (optimal threshold from receiver operating characteristic [ROC] analysis of 12-month OS data) were 14.2 and 6.0 months, as compared to 6.6 and 2.8 months for patients with rCBV-values greater than 3.92 (P < .01, respectively). cT1 and FLAIR volumes at first follow-up were significant predictors of 6-month PFS and 12-month OS in the BEV cohort but not in the non-BEV cohort. Corresponding volumes at baseline were not significant in any cohort.

CONCLUSIONS

Pretreatment rCBV is a potential predictive imaging biomarker in BEV-treated rGB but not alkylating chemotherapy-treated rGB, which is superior to volumetric analysis of conventional anatomic MRI and predicts 6-month PFS and 12-month OS in 80% of BEV-treated patients.

How treatment monitoring is influencing treatment decisions in glioblastomas

OPINION STATEMENT

Glioblastoma (GBM), the most common malignant primary tumor in adults, carries a dismal prognosis with an average median survival of 14-16 months. The current standard of care for newly diagnosed GBM consists of maximal safe resection followed by fractionated radiotherapy combined with concurrent temozolomide and 6 to 12 cycles of adjuvant temozolomide. The determination of treatment response and clinical decision-making in the treatment of GBM depends on accurate radiographic assessment. Differentiating treatment response from tumor progression is challenging and combines long-term follow-up using standard MRI, with assessing clinical status and corticosteroid dependency. At progression, bevacizumab is the mainstay of treatment. Incorporation of antiangiogenic therapies leads to rapid blood-brain barrier normalization with remarkable radiographic response often not accompanied by the expected survival benefit, further complicating imaging assessment. Improved radiographic interpretation criteria, such as the Response Assessment in Neuro-Oncology (RANO) criteria, incorporate non-enhancing disease but still fall short of definitely distinguishing tumor progression, pseudoresponse, and pseudoprogression. With new evolving treatment modalities for this devastating disease, advanced imaging modalities are increasingly becoming part of routine clinical care in a field where neuroimaging has such essential role in guiding treatment decisions and defining clinical trial eligibility and efficacy.

Pitfalls in the neuroimaging of glioblastoma in the era of antiangiogenic and immuno/targeted therapy - detecting illusive disease, defining response

Glioblastoma, the most common malignant primary brain tumor in adults is a devastating diagnosis with an average survival of 14–16 months using the current standard of care treatment. The determination of treatment response and clinical decision making is based on the accuracy of radiographic assessment. Notwithstanding, challenges exist in the neuroimaging evaluation of patients undergoing treatment for malignant glioma. Differentiating treatment response from tumor progression is problematic and currently combines long-term follow-up using standard magnetic resonance imaging (MRI), with clinical status and corticosteroid-dependency assessments. In the clinical trial setting, treatment with gene therapy, vaccines, immunotherapy, and targeted biologicals similarly produces MRI changes mimicking disease progression. A neuroimaging method to clearly distinguish between pseudoprogression and tumor progression has unfortunately not been found to date. With the incorporation of antiangiogenic therapies, a further pitfall in imaging interpretation is pseudoresponse. The Macdonald criteria that correlate tumor burden with contrast-enhanced imaging proved insufficient and misleading in the context of rapid blood–brain barrier normalization following antiangiogenic treatment that is not accompanied by expected survival benefit. Even improved criteria, such as the RANO criteria, which incorporate non-enhancing disease, clinical status, and need for corticosteroid use, fall short of definitively distinguishing tumor progression, pseudoresponse, and pseudoprogression. This review focuses on advanced imaging techniques including perfusion MRI, diffusion MRI, MR spectroscopy, and new positron emission tomography imaging tracers. The relevant image analysis algorithms and interpretation methods of these promising techniques are discussed in the context of determining response and progression during treatment of glioblastoma both in the standard of care and in clinical trial context.

Phase 1 dose-escalation study of the antiplacental growth factor monoclonal antibody RO5323441 combined with bevacizumab in patients with recurrent glioblastoma

BACKGROUND

We conducted a phase 1 dose-escalation study of RO5323441, a novel antiplacental growth factor (PlGF) monoclonal antibody, to establish the recommended dose for use with bevacizumab and to investigate the pharmacokinetics, pharmacodynamics, safety/tolerability, and preliminary clinical efficacy of the combination.

METHODS

Twenty-two participants with histologically confirmed glioblastoma in first relapse were treated every 2 weeks with RO5323441 (625 mg, 1250 mg, or 2500 mg) plus bevacizumab (10 mg/kg). A standard 3 + 3 dose-escalation trial design was used.

RESULTS

RO5323441 combined with bevacizumab was generally well tolerated, and the maximum tolerated dose was not reached. Two participants experienced dose-limiting toxicities (grade 3 meningitis associated with spinal fluid leak [1250 mg] and grade 3 cerebral infarction [2500 mg]). Common adverse events included hypertension (14 participants, 64%), headache (12 participants, 55%), dysphonia (11 participants, 50%) and fatigue (6 participants, 27%).The pharmacokinetics of RO5323441 were linear, over-the-dose range, and bevacizumab exposure was unaffected by RO5323441 coadministration. Modulation of plasmatic angiogenic proteins, with increases in VEGFA and decreases in FLT4, was observed. Dynamic contrast-enhanced/diffusion-weighted MRI revealed large decreases in vascular parameters that were maintained through the dosing period. Combination therapy achieved an overall response rate of 22.7%, including one complete response, and median progression-free and overall survival of 3.5 and 8.5 months, respectively.

CONCLUSION

The toxicity profile of RO5323441 plus bevacizumab was acceptable and manageable. The observed clinical activity of the combination does not appear to improve on that obtained with single-agent bevacizumab in patients with recurrent glioblastoma.

MGMT Promoter Methylation Is a Strong Prognostic Biomarker for Benefit from Dose-Intensified Temozolomide Rechallenge in Progressive Glioblastoma: The DIRECTOR Trial

PURPOSE

Rechallenge with temozolomide (TMZ) at first progression of glioblastoma after temozolomide chemoradiotherapy (TMZ/RT→TMZ) has been studied in retrospective and single-arm prospective studies, applying temozolomide continuously or using 7/14 or 21/28 days schedules. The DIRECTOR trial sought to show superiority of the 7/14 regimen.

EXPERIMENTAL DESIGN

Patients with glioblastoma at first progression after TMZ/RT→TMZ and at least two maintenance temozolomide cycles were randomized to Arm A [one week on (120 mg/m(2) per day)/one week off] or Arm B [3 weeks on (80 mg/m(2) per day)/one week off]. The primary endpoint was median time-to-treatment failure (TTF) defined as progression, premature temozolomide discontinuation for toxicity, or death from any cause. O(6)-methylguanine DNA methyltransferase (MGMT) promoter methylation was prospectively assessed by methylation-specific PCR.

RESULTS

Because of withdrawal of support, the trial was prematurely closed to accrual after 105 patients. There was a similar outcome in both arms for median TTF [A: 1.8 months; 95% confidence intervals (CI), 1.8-3.2 vs. B: 2.0 months; 95% CI, 1.8-3.5] and overall survival [A: 9.8 months (95% CI, 6.7-13.0) vs. B: 10.6 months (95% CI, 8.1-11.6)]. Median TTF in patients with MGMT-methylated tumors was 3.2 months (95% CI, 1.8-7.4) versus 1.8 months (95% CI, 1.8-2) in MGMT-unmethylated glioblastoma. Progression-free survival rates at 6 months (PFS-6) were 39.7% with versus 6.9% without MGMT promoter methylation.

CONCLUSIONS

Temozolomide rechallenge is a treatment option for MGMT promoter-methylated recurrent glioblastoma. Alternative strategies need to be considered for patients with progressive glioblastoma without MGMT promoter methylation.

Dynamic susceptibility contrast MRI measures of relative cerebral blood volume as a prognostic marker for overall survival in recurrent glioblastoma: results from the ACRIN 6677/RTOG 0625 multicenter trial

BACKGROUND

The study goal was to determine whether changes in relative cerebral blood volume (rCBV) derived from dynamic susceptibility contrast (DSC) MRI are predictive of overall survival (OS) in patients with recurrent glioblastoma multiforme (GBM) when measured 2, 8, and 16 weeks after treatment initiation.

METHODS

Patients with recurrent GBM (37/123) enrolled in ACRIN 6677/RTOG 0625, a multicenter, randomized, phase II trial of bevacizumab with irinotecan or temozolomide, consented to DSC-MRI plus conventional MRI, 21 with DSC-MRI at baseline and at least 1 postbaseline scan. Contrast-enhancing regions of interest were determined semi-automatically using pre- and postcontrast T1-weighted images. Mean tumor rCBV normalized to white matter (nRCBV) and standardized rCBV (sRCBV) were determined for these regions of interest. The OS rates for patients with positive versus negative changes from baseline in nRCBV and sRCBV were compared using Wilcoxon rank-sum and Kaplan-Meier survival estimates with log-rank tests.

RESULTS

Patients surviving at least 1 year (OS-1) had significantly larger decreases in nRCBV at week 2 (P = .0451) and sRCBV at week 16 (P = .014). Receiver operating characteristic analysis found the percent changes of nRCBV and sRCBV at week 2 and sRCBV at week 16, but not rCBV data at week 8, to be good prognostic markers for OS-1. Patients with positive change from baseline rCBV had significantly shorter OS than those with negative change at both week 2 and week 16 (P = .0015 and P = .0067 for nRCBV and P = .0251 and P = .0004 for sRCBV, respectively).

CONCLUSIONS

Early decreases in rCBV are predictive of improved survival in patients with recurrent GBM treated with bevacizumab.

Impact of bevacizumab administered dose on overall survival of patients with progressive glioblastoma

Bevacizumab (BEV, Avastin(®)) produces durable objective radiological responses of 20-26 %, median response durations of 16-18 weeks, and median overall survival (mOS) of 31-40 weeks. While the use of BEV is well-established, the lack of dose-response studies in glioblastoma (GBM) patients raises the question whether current dosing practice is optimal. As a result of differing approaches to BEV dosing that ranged from the FDA approved package insert dose of 10 mg/kg every 2 weeks to 7.5 mg/kg every 3-4 weeks, among physicians within Northern California Kaiser Permanente hospitals over 4+ years, we did an IRB-approved retrospective analysis of patients seen in Northern California Kaiser Permanente facilities and treated with BEV. Between September 1, 2008 and August 31, 2013, 181 patients received BEV for tumor progression/recurrence starting 2.6 weeks after completion of chemoradiation. The integrated BEV administered dose-week (AUCBEV) for all patients had a median AUCBEV of 3.6 mg·wk/kg). Maximum likelihood analysis found patients over 65 years did worse than younger patients (p = 0.004), women lived longer (p = 0.002), and patients treated below the AUCBEV did better than those treated above the median AUCBEV (p = 0.003). mOS for BEV starting 1 month after chemoradiation was 45 versus 68 weeks (p = 0.012) and BEV starting 3 months after chemoradiation was 40 versus 74 weeks (p = 0.0085). Dosing BEV at half the standard dose for progressive/recurrent GBM was at least equivalent to or, maybe better than standard dosing. Unexplained was the observation that females had longer OS with BEV than males.

Patient outcome in the Belgian medical need program on bevacizumab for recurrent glioblastoma

Bevacizumab (BEV) has demonstrated anti-tumor activity in patients with recurrent glioblastoma (rGB). Given the unmet need for active therapeutic options in rGB patients, a medical need program was initiated by the Belgian competent authorities. Between November 2010 and February 2013, a total of 313 patients with rGB initiated treatment with BEV administered at a dose of 10 mg/kg every 2 weeks. All patients had failed prior treatment with at least radiation therapy and temozolomide and the majority of patients (70 %) were treated with corticosteroids at baseline. Patients received a median of 6 BEV administrations (range 1-53). Overall, BEV was well tolerated. During BEV treatment the WHO-Performance Score (WHO-PS) improved in 59 patients (19 %) and stabilized for at least 6 weeks in an additional 139 (44 %) patients. Corticosteroid treatment could be stopped in 16 % or reduced in dose in 32 % of patients. The best objective tumor response rate using RANO criteria (investigator's assessment) was 3.5 % CR, 22 % PR, 38 % SD and 37 % PD. The median and 6-month PFS were 13 weeks (95 % CI 12.7-14) and 27.3 % (95 % CI 22.3-32.5), median and 6-month OS rates were 26 weeks (23-29) and 52 % (46.4-58.6), respectively. WHO-PS (0-1 vs. 2-3) and baseline steroid use were significantly correlated with PFS and OS. Our observations support the use of BEV as a monotherapy for patients with rGB who have no alternative treatment options. Optimal benefit from BEV treatment is likely to be obtained when treatment is initiated before the performance status deteriorates to two or less.

Practical management of bevacizumab-related toxicities in glioblastoma

Bevacizumab, currently an option for treatment of different types of tumors including glioblastoma, has a peculiar toxicity profile related to its antiangiogenic effect. Because some bevacizumab-related adverse events can be life threatening, it is important to identify risk factors and to establish treatment protocols to minimize treatment-related morbidity and mortality. In glioblastoma patients, the risk of developing certain side effects, such as gastrointestinal perforation, venous thromboembolism, and intracranial hemorrhages, is slightly higher than in patients treated with bevacizumab for other tumor types. We performed a systematic review of the side effects of bevacizumab and their incidence, causal mechanisms, and available treatments. Finally, we identified risk factors and proposed preventive and therapeutic measures for these adverse events.

Phase II study of panobinostat in combination with bevacizumab for recurrent glioblastoma and anaplastic glioma

BACKGROUND

Panobinostat is a histone deacetylase inhibitor with antineoplastic and antiangiogenic effects in glioma that may work synergistically with bevacizumab. We conducted a multicenter phase II trial of panobinostat combined with bevacizumab in patients with recurrent high-grade glioma (HGG).

METHODS

Patients with recurrent HGG were treated with oral panobinostat 30 mg 3 times per week, every other week, in combination with bevacizumab 10 mg/kg every other week. The primary endpoint was a 6-month progression-fee survival (PFS6) rate for participants with recurrent glioblastoma (GBM). Patients with recurrent anaplastic glioma (AG) were evaluated as an exploratory arm of the study.

RESULTS

At interim analysis, the GBM arm did not meet criteria for continued accrual, and the GBM arm was closed. A total of 24 patients with GBM were accrued prior to closure. The PFS6 rate was 30.4% (95%, CI 12.4%-50.7%), median PFS was 5 months (range, 3-9 months), and median overall survival (OS) was 9 months (range, 6-19 months). Accrual in the AG arm continued to completion, and a total of 15 patients were enrolled. The PFS6 rate was 46.7% (range, 21%-73%), median PFS was 7 months (range, 2-10 months), and median OS was 17 months (range, 5 months-27 months).

CONCLUSIONS

This phase II study of panobinostat and bevacizumab in participants with recurrent GBM did not meet criteria for continued accrual, and the GBM cohort of the study was closed. Although it was reasonably well tolerated, the addition of panobinostat to bevacizumab did not significantly improve PFS6 compared with historical controls of bevacizumab monotherapy in either cohort.

Glioma in 2014: unravelling tumour heterogeneity-implications for therapy

Heterogeneity within and across tumours is increasingly recognized as a critical factor that limits therapeutic progress for many cancers. Key studies reported in 2014 describe previously unappreciated patterns of geographical and temporal heterogeneity for glioblastoma (the most-common primary CNS tumour in adults), with important implications for ongoing therapeutic studies evaluating molecular targeted therapies.

Chemoresistance and chemotherapy targeting stem-like cells in malignant glioma

Glioblastoma remains a tumor with a dismal prognosis because of failure of current treatment. Glioblastoma cells with stem cell (GSC) properties survive chemotherapy and give rise to tumor recurrences that invariably result in the death of the patients. Here we summarize the current knowledge on chemoresistance of malignant glioma with a strong focus on GSC. Chemoresistant GSC are the most likely cause of tumor recurrence, but it remains controversial if GSC and under which conditions GSC are more chemoresistant than non-GSC within the tumor. Regardless of this uncertainty, the chemoresistance varies and it is mainly mediated by intrinsic factors. O6-methyl-guanidine methyltransferase (MGMT) remains the most potent mediator of chemoresistance, but disturbed mismatch repair system and multidrug resistance proteins contribute substantially. However, the intrinsic resistance by MGMT expression is regulated by extrinsic factors like hypoxia increasing MGMT expression and thereby resistance to alkylating chemotherapy. The search of new biomarkers helping to predict the tumor response to chemotherapy is ongoing and will complement the already known markers like MGMT.

Advances and challenges in the molecular biology and treatment of glioblastoma-is there any hope for the future?

Malignant gliomas, such as glioblastoma multiforme (GBM), present some of the greatest challenges in the management of cancer patients worldwide. Even with aggressive surgical resections and recent advances in radiotherapy and chemotherapy, the prognosis for GBM patients remains dismal and quality of life is poor. Although new molecular pathways crucial to the biology and invasive ability of GBM are coming to light, translation of basic science achievements into clinical practice is slow. Optimal management requires a multidisciplinary approach and knowledge of potential complications arising from both disease and treatment. To help illustrate "where we are going" with GBM, we here include a detailed depiction of the molecular alterations underlying this fatal disease, as well as intensive research over the past two decades that has led to considerable advances in the understanding of basic GBM biology, pathogenesis and therapeutic approaches.

Bevacizumab-induced hypertension is a predictive marker for improved outcomes in patients with recurrent glioblastoma treated with bevacizumab

BACKGROUND

Bevacizumab is a monoclonal antibody targeting vascular endothelial growth factor and is approved for the treatment of patients with recurrent glioblastoma (GBM). Previous authors have reported differential response to bevacizumab on an individual basis. Bevacizumab-induced hypertension is a well-documented side effect, and some reports have suggested this occurrence to be related to treatment outcome in other cancers. In the current study, the authors analyzed patients with recurrent GBM who were treated with bevacizumab based on whether the patients developed drug-induced hypertension.

METHODS

All patients with GBM treated within the Emory Healthcare system from 2007 through 2012 were reviewed. A total of 82 patients were identified who received bevacizumab for the treatment of recurrent GBM and were included in the current study. Patients were classified as normotensive or hypertensive depending on whether hypertension developed that was attributable to therapy. Progression-free survival (PFS) and overall survival (OS) were graphed by the Kaplan-Meier method. Univariate and multivariate analyses were performed using the Cox proportional hazards method.

RESULTS

The median follow-up was 19.7 months. Of the 82 patients with recurrent GBM who were treated with bevacizumab, 30 developed drug-induced hypertension. The median time to the development of hypertension was 21 days. The median PFS for the normotensive and hypertensive groups were 2.5 months (95% confidence interval [95% CI], 1.6-3.0 months) and 6.7 months (95% CI, 4.6-10.0 months), respectively (P<.001). The median OS times for the normotensive and hypertensive groups were 4.9 months (95% CI, 4.4-6.8 months) and 11.7 months (95% CI, 9.0-20.5 months), respectively (P<.001).

CONCLUSIONS

Patients with recurrent GBM who developed bevacizumab-induced hypertension demonstrated significantly better PFS and OS compared with normotensive individuals. Bevacizumab-induced hypertension may be a physiologic marker of outcome in patients with recurrent GBM.

Current standards and new concepts in MRI and PET response assessment of antiangiogenic therapies in high-grade glioma patients

Despite multimodal treatment, the prognosis of high-grade gliomas is grim. As tumor growth is critically dependent on new blood vessel formation, antiangiogenic treatment approaches offer an innovative treatment strategy. Bevacizumab, a humanized monoclonal antibody, has been in the spotlight of antiangiogenic approaches for several years. Currently, MRI including contrast-enhanced T1-weighted and T2/fluid-attenuated inversion recovery (FLAIR) images is routinely used to evaluate antiangiogenic treatment response (Response Assessment in Neuro-Oncology criteria). However, by restoring the blood-brain barrier, bevacizumab may reduce T1 contrast enhancement and T2/FLAIR hyperintensity, thereby obscuring the imaging-based detection of progression. The aim of this review is to highlight the recent role of imaging biomarkers from MR and PET imaging on measurement of disease progression and treatment effectiveness in antiangiogenic therapies. Based on the reviewed studies, multimodal imaging combining standard MRI with new physiological MRI techniques and metabolic PET imaging, in particular amino acid tracers, may have the ability to detect antiangiogenic drug susceptibility or resistance prior to morphological changes. As advances occur in the development of therapies that target specific biochemical or molecular pathways and alter tumor physiology in potentially predictable ways, the validation of physiological and metabolic imaging biomarkers will become increasingly important in the near future.

Dose-dense temozolomide: is it still promising?

Glioblastoma (GBM) has proven to be incurable despite recent progress on its standard of care using temozolomide (TMZ) as the main trunk of initial therapy for newly diagnosed GBM. One of the main reasons accounting for the dismal prognosis is attributed to lack of active therapeutic regimens at recurrence. Since TMZ is the most active cytotoxic agent against GBM, and the standard dosing of TMZ has shown favorable safety profile in clinical trials, re-challenge with TMZ in increased dose density schedules for recurrent tumors that have evaded from prior standard TMZ therapy appears to be a rational approach and has been intensively exploited. A number of phase II clinical trials using different alternating scheduling of dose-dense TMZ (ddTMZ) have shown superior efficacy over the standard TMZ or historical controls with other alkylating agents including nitrosoureas and procarbazine. One ddTMZ schedule, consisting of a 21-days on/7-days off regimen was applied to newly-diagnosed GBM as the adjuvant monotherapy after completion of combined radiation and TMZ and failed to demonstrate survival benefit in a large phase III trial (RTOG 0525). Thus its role in TMZ-pretreated, recurrent GBM should be carefully pursuit in randomized trials, e.g., planned JCOG 1308 trial comparing a 7-days on/7-days off ddTMZ regimen used upfront at the first relapse followed by bevacizumab on progression versus bevacizumab alone, investigating whether insertion of ddTMZ prior to bevacizumab could bestow better outcome in the recurrent setting. In this article, mode of action, past trials, and future directions of ddTMZ therapy are discussed.

Pharmacologic therapies for malignant glioma: a guide for clinicians

This review covers the medical options for malignant gliomas based on the results of recent clinical trials and updated information on molecular markers of prognostic and predictive value. In addition to alkylating agents, the antiangiogenic drug bevacizumab is increasingly used, particularly in cases of recurrence. Supportive care, including antiedema agents, antiepileptic drugs and anticoagulants, represent complementary treatment approaches of the utmost clinical importance.

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.

Antiangiogenic therapy for glioblastoma: current status and future prospects

Glioblastoma is characterized by high expression levels of proangiogenic cytokines and microvascular proliferation, highlighting the potential value of treatments targeting angiogenesis. Antiangiogenic treatment likely achieves a beneficial impact through multiple mechanisms of action. Ultimately, however, alternative proangiogenic signal transduction pathways are activated, leading to the development of resistance, even in tumors that initially respond. The identification of biomarkers or imaging parameters to predict response and to herald resistance is of high priority. Despite promising phase II clinical trial results and patient benefit in terms of clinical improvement and longer progression-free survival, an overall survival benefit has not been demonstrated in four randomized phase III trials of bevacizumab or cilengitide in newly diagnosed glioblastoma or cediranib or enzastaurin in recurrent glioblastoma. However, future studies are warranted. Predictive markers may allow appropriate patient enrichment, combination with chemotherapy may ultimately prove successful in improving overall survival, and novel agents targeting multiple proangiogenic pathways may prove effective.

Post progression survival in glioblastoma: where are we?

The optimal end point for phase II studies for recurrent glioblastoma (GBM) is unclear and a matter of debate. Moreover, data about post-progression survival (PPS) after the first disease progression in GBM patients treated according to EORTC 26981/22981/NCIC CE.3 trial are limited. The aim of this study was to evaluate the PPS in GBM patients. The analysis was made with a database on 1,006 GBM patients followed prospectively between 06/2005 and 06/2010. Eligibility criteria for the study were: age ≥ 18 years; PS: 0-2; chemotherapy given at disease progression after RT/TMZ. 232 patients (mean age 52 years, range 18-77 years) were enrolled. The median PFS following second line chemotherapy (PFS2) was 2.5 months (95 % CI 2.1-2.9) and the rate of patients free of progression at 6 months (PFS2-6 mo), was 21.6 % (95 % CI 16.3-26.9 %). The median PPS was 8.6 months (95 % CI 7.4-9.8), PPS rates were: PPS-6: 66 % (95 % CI 60.3-72.9 %), PPS-9: 48.2 % (95 % CI 41.5-54.9 %) and PPS-12: 31.7 % (95 % CI 25.2-38.2 %). PPS in unselected patients treated with alkylating agents is about 8 months. PPS rates could be of interest as an end point in future studies in recurrent GBM.