Prolonged treatment with bevacizumab is associated with brain atrophy: a pilot study in patients with high-grade gliomas

Bevacizumab is associated with cerebral microstructural alterations: a DTI study in high-grade glioma

Background

For recurrent high-grade glioma, especially glioblastoma, no standard of care treatment exists. Due to the prolongation of progression-free survival and a cortiocosteroid-sparing effect, bevacizumab is often used in this condition. Despite initial clinical responses, there is growing evidence that bevacizumab may potentiate microstructural alterations which may cause cognitive decline, mostly affecting learning and memory.

Methods

To investigate bevacizumab-associated microstructural damage of defined regions of interest (ROIs) in the white matter, diffusion tensor imaging (DTI) was performed in 10 patients with a case history or third-party report for neurological dysfunction concerning cognitive performance. Serial DTI data before and under bevacizumab were collected and longitudinal changes of fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) were assessed in mesiotemporal (hippocampal), frontal, and occipital regions.

Results

The longitudinal DTI data under bevacizumab compared to DTI prior to bevacizumab demonstrated a significant decrease in FA and increase in AD and RD both in mesiotemporal (hippocampal) regions and in frontal regions, whereas occipital regions showed no significant alterations in DTI metrics.

Conclusion

The regionally impaired microstructure in mesiotemporal (hippocampal) regions and in frontal regions is in line with the fact that neurocognitive impairment in learning and memory is mostly related to hippocampal integrity and attentional control in frontal regions. Further studies could investigate the potential of DTI to assess bevacizumab-associated microstructural damages in vulnerable brain regions.

Update on Chemotherapeutic Approaches and Management of Bevacizumab Usage for Glioblastoma

Glioblastoma, the most common primary brain tumor in adults, has one of the most dismal prognoses in cancer. In 2009, bevacizumab was approved for recurrent glioblastoma in the USA. To evaluate the clinical impact of bevacizumab as a first-line drug for glioblastoma, two randomized clinical trials, AVAglio and RTOG 0825, were performed. Bevacizumab was found to improve progression-free survival (PFS) and was reported to be beneficial for maintaining patient performance status as an initial treatment. These outcomes led to bevacizumab approval in Japan in 2013 as an insurance-covered first-line drug for glioblastoma concurrently with its second-line application. However, prolongation of overall survival was not evinced in these clinical trials; hence, the clinical benefit of bevacizumab for newly diagnosed glioblastomas remains controversial. A recent meta-analysis of randomized controlled trials of bevacizumab combined with temozolomide in recurrent glioblastoma also showed an effect only on PFS, and the benefit of bevacizumab even for recurrent glioblastoma is controversial. Here, we discuss the clinical impact of bevacizumab for glioblastoma treatment by reviewing previous clinical trials and real-world evidence by focusing on Japanese experiences. Moreover, the efficacy and safety of bevacizumab are summarized, and we provide suggestions for updating the approaches and management of bevacizumab.

Mitochondrial-associated impairments of temozolomide on neural stem/progenitor cells and hippocampal neurons

Primary brain tumor patients often experience neurological, cognitive, and depressive symptoms that profoundly affect quality of life. The DNA alkylating agent, temozolomide (TMZ), along with radiation therapy forms the standard of care for glioblastoma (GBM) - the most common and aggressive of all brain cancers. Numerous studies have reported that TMZ disrupts hippocampal neurogenesis and causes spatial learning deficits in rodents; however, the effect of TMZ on mature hippocampal neurons has not been addressed. In this study, we examined the mitochondrial-mediated mechanisms involving TMZ-induced neural damage in primary rat neural stem/progenitor cells (NSC) and hippocampal neurons. TMZ inhibited mtDNA replication and transcription of mitochondrial genes (ND1 and Cyt b) in NSC by 24 h, whereas the effect of TMZ on neuronal mtDNA transcription was less pronounced. Transmission electron microscopy imaging revealed mitochondrial degradation in TMZ-treated NSC. Acute TMZ exposure (4 h) caused a rapid reduction in dendritic branching and loss of postsynaptic density-95 (PSD95) puncta on dendrites. Longer TMZ exposure impaired mitochondrial respiratory activity, increased oxidative stress, and induced apoptosis in hippocampal neurons. The presented findings suggest that NSC may be more vulnerable to TMZ than hippocampal neurons upon acute exposure; however long-term TMZ exposure results in neuronal mitochondrial respiratory dysfunction and dendritic damage, which may be associated with delayed cognitive impairments.

Assessment of neurocognitive decline in cancer patients, except brain cancer, under long-term treatment with bevacizumab

PURPOSE

We performed a cross-sectional study of neurocognitive function in non-brain cancer patients treated with long-term bevacizumab.

METHODS/PATIENTS

From 2015 to 2017, we included patients with different types of cancer treated with bevacizumab with or without chemotherapy (BEV; N = 20) or only chemotherapy (ChT; N = 19) for at least 34 weeks, patients who received non-brain radiotherapy (RxT; N = 19), and healthy controls (HC; N = 19) were assessed once at week 34 of treatment (BEV and ChT) or at completion of radiotherapy. Neurocognition was evaluated with the Hopkins Verbal Learning Test-Revised (HVLT-R) total and delayed recall, the Trail Making Test A and B, and the Controlled Oral Word Association Test in the four groups. Non-parametric tests were used to assess differences between groups.

RESULTS

The BEV, ChT, and RxT groups scored significantly lower than the HC group on all tests and especially on the HVLT-R total recall. In no case were the mean scores of the BEV group significantly lower than those of the ChT or RxT groups.

CONCLUSIONS

Neurocognitive impairment was seen even in patients treated with local non-brain radiotherapy. Treatment with bevacizumab for a long period of time does not seem to worsen neurocognitive function to a greater extent than chemotherapy.

Optimizing intrapleural bevacizumab dosing in non-small-cell lung cancer-mediated malignant pleural effusion: less is more

AIM

Intrapleural infusion of bevacizumab (BEV) is an emerging clinical treatment for malignant pleural effusion, but many details of usage need to be determined, especially for the effective dose.

PATIENTS & METHODS

We performed a retrospective study of the records of malignant pleural effusion patients from non-small-cell lung cancer who underwent intrapleural infusion of BEV. According to the BEV dose commonly used in clinical, patients were allocated into either low-dose group or high-dose group.

RESULTS

A total of 71 patients were enrolled in this study. Administration with intrapleural BEV in low dose has less toxicity. For survival data, low- and high-dose groups have no difference.

CONCLUSION

Lower rates of serious BEV-related toxicities and similar survival date are noted when lower dosages are used without diminishing positive clinical impact.

Optimizing bevacizumab dosing in glioblastoma: less is more

Compared to traditional chemotherapies, where dose limiting toxicities represent the maximum possible dose, monoclonal antibody therapies are used at doses well below maximum tolerated dose. However, there has been little effort to ascertain whether there is a submaximal dose at which the efficacy/complication ratio is maximized. Thus, despite the general practice of using Bevacizumab (BEV) at dosages of 10 mg/kg every other week for glioma patients, there has not been much prior work examining whether the relatively high complication rates reported with this agent can be decreased by lowering the dose without impairing efficacy. We assessed charts from 80 patients who received BEV for glioblastoma to survey the incidence of complications relative to BEV dose. All patients were treated with standard upfront chemoradiation. The toxicity was graded based on the NCI CTCAE, version 4.03. The rate of BEV serious related adverse events was 12.5% (n = 10/80). There were no serious adverse events (≥grade 3) when the administered dose was (<3 mg/kg/week), compared to a 21% incidence in those who received higher doses (≥3 mg/kg/week) (P < 0.01). Importantly, the three patient deaths attributable to BEV administration occurred in patients receiving higher doses. Patients who received lower doses also had a better survival rate, although this did not reach statistical significance [median OS 39 for low dose group vs. 17.3 for high dose group (P = 0.07)]. Lower rates of serious BEV related toxicities are noted when lower dosages are used without diminishing positive clinical impact. Further work aimed at optimizing BEV dosage is justified.

Add-on bevacizumab can prevent early clinical deterioration and prolong survival in newly diagnosed partially resected glioblastoma patients with a poor performance status

Purpose

The AVAglio trial established the beneficial effect of add-on bevacizumab (BEV) for the treatment of newly diagnosed glioblastomas (nd-GBMs) that led to the approval of BEV for the treatment of these patients in Japan. However, the rationality of using BEV as a first-line treatment for nd-GBMs remains controversial. The purpose of this study was to analyze the outcomes of a case series of nd-GBM patients.

Patients and methods

The outcomes of 69 nd-GBM patients treated after 2006 were retrospectively analyzed. Clinical and genetic analyses were performed, and estimates of progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan–Meier method. Since add-on BEV therapy was only used for partially resected GBMs (pr-GBMs) after its approval in 2013, the patients were subdivided into 3 treatment groups: Type I, partial removal with temozolomide (TMZ)/BEV and concurrent radiotherapy (CCRT); Type II, partial removal with TMZ and CCRT; and Type III, gross total removal with TMZ and CCRT.

Results

The PFS rate of Type I patients was significantly higher than that of Type II patients (P=0.014), but comparable to that of Type III patients. Differences in OS rates between Type I and Type II patients were less apparent (P=0.075), although the median OS of Type I patients was ~8 months higher than that of Type II patients (17.4 vs 9.8 months, respectively). The clinical deterioration rate during initial treatment was significantly (P=0.024) lower in Type I than in Type II patients (7.7% vs 47.4%, respectively). Differences in OS rates between Type I and Type II patients with a poor performance status (PS) were significant (P=0.017).

Conclusion

Our findings suggest that add-on BEV can prevent early clinical deterioration of pr-GBM patients and contribute to a prolonged survival, especially for those with a poor PS.

Determining priority signs and symptoms for use as clinical outcomes assessments in trials including patients with malignant gliomas: Panel 1 Report

Patients with primary brain tumors such as malignant gliomas are highly symptomatic, often from the time of diagnosis. Signs and symptoms (signs/symptoms) can cause functional limitations that often worsen over the disease trajectory and may impact patient quality of life. It is recognized that standard measurements of tumor response do not adequately measure this impact or the impact that a therapy may have to mitigate these signs/symptoms and potentially have clinical benefit. Identifying a core set of signs/symptoms and functional limitations is important for understanding their clinical impact and is the first step to including clinical outcomes assessment in primary brain tumor clinical trials.

Bevacizumab and radiotherapy for the treatment of glioblastoma: brothers in arms or unholy alliance?

Glioblastoma (GBM) represents the most frequent primary brain tumor in adults and carries a dismal prognosis despite aggressive, multimodal treatment regimens involving maximal resection, radiochemotherapy, and maintenance chemotherapy. Histologically, GBMs are characterized by a high degree of VEGF-mediated vascular proliferation. In consequence, new targeted anti-angiogenic therapies, such as the monoclonal anti-VEGF-A antibody bevacizumab, have proven effective in attenuating tumor (neo)angiogenesis and were shown to possess therapeutic activity in several phase II trials. However, the role of bevacizumab in the context of multimodal therapy approaches appears to be rather complex. This review will give insights into current concepts, limitations, and controversies regarding the molecular mechanisms and the clinical benefits of bevacizumab treatment in combination with radio(chemo)therapy - particularly in face of the results of recent phase III trials, which failed to demonstrate convincing improvements in overall survival (OS).

Prolonged survival after bevacizumab rechallenge in glioblastoma patients with previous response to bevacizumab†

Background

The use of bevacizumab for recurrent glioblastoma is controversial. Here we show data on patients who responded to bevacizumab, then stopped bevacizumab for any reason other than progression and were rechallenged with bevacizumab at the time of subsequent progression.

Methods

This retrospective study included 28 patients, classified in 2 cohorts: those for whom the first exposure to bevacizumab (BEV-1) was first-line treatment for newly diagnosed glioblastoma (Bev-F; N = 12) and those for whom BEV-1 was second- or third-line treatment for recurrent disease after standard treatment (Bev-S; N = 16).

Results

All patients received standard radiotherapy plus temozolomide. Bev-F patients also received concomitant bevacizumab. All 28 patients received a total of 57 treatment lines with bevacizumab (12 first-line and 45 second- or further-line). Twenty-nine lines were rechallenges (BEV-2 [N = 26] or BEV-3 [N = 3]). Objective response to rechallenge was 58.6% and clinical benefit was 89.6%. Overall survival (OS) was 55 months for RPA class IV and 26.7 months for RPA class V patients (P = .01). OS was 26.7 months for Bev-F patients and 52.1 months for Bev-S patients (P = .004). Post-progression survival was 20 months for Bev-F patients and 39.6 months for Bev-S patients (HR = 0.26; P = .007).

Conclusion

This is the largest study to examine the impact of a bevacizumab rechallenge in glioblastoma patients who had responded to previous bevacizumab treatment but who stopped before progression. Our findings indicate that these patients can attain a second response or clinical benefit from re-introduction of bevacizumab. The potential benefit from intermittent versus continuous treatment warrants comparison in clinical trials.

The effects of sequential treatments on hippocampal volumes in malignant glioma patients

Malignant gliomas (MG) are very aggressive tumors. In an effort to improve the outcome, the patients receive multi-modal therapies such as surgery, radiation and chemotherapy (temozolomide followed in many cases by bevacizumab). The survivors are affected by multiple learning and memory deficits. Greater deterioration over time in hippocampal specific cognitive tasks was shown in patients receiving bevacizumab in addition to radiation and temozolomide for a longer period of time (RTOG 0825). The rate of hippocampal atrophy in patients treated with radiation and temozolomide followed by bevacizumab is not yet determined, and is the goal of the present study. We used the serial MRIs obtained as parts of standard clinical care in patients with MG. Measurements were done using the Medical Image Processing, Analysis and Visualization (MIPAV) software. The hippocampus in the contralateral hemisphere was manually traced and measured, to avoid morphological structure changes induced by the tumor, radiation fields or surgical markers. We determined a longitudinal progression of hippocampal atrophy-with the maximum volume loss (33.26 %) for the patients that were on treatment for 5 years. There was no detectable hippocampal atrophy during the chemo-radiation followed by adjuvant temozolomide. A significant decrease in the absolute hippocampus volume was noted after 6 months of continuous bevacizumab treatment (p < 0.05). The hippocampal volume loss progressed over the next 3 years, and was higher than the one previously reported in Alzheimer disease patients. The hippocampal volume loss is minimal during the 1 month after diagnosis, when the patients receive chemo-radiation and adjuvant temozolomide. However, prolonged treatment including bevacizumab is associated with a significant rate of hippocampal volume loss.