Drug review: Safety and efficacy of bevacizumab for glioblastoma and other brain tumors

Stereotactic radiosurgery versus combined stereotactic radiosurgery and bevacizumab for recurrent glioblastoma; a systematic review and meta-analysis of survival

Recurrent glioblastoma (rGBM) is a brain tumor that is resistant to standard treatments. Although stereotactic radiosurgery (SRS) is a non-invasive radiation technique, it cannot fully prevent tumor recurrence and progression. Bevacizumab blocks tumor blood supply and has been approved for rGBM. However, the best way to combine SRS and bevacizumab is still unclear. We did a systematic review and meta-analysis of studies comparing SRS alone and SRS plus bevacizumab for rGBM. We searched three databases for articles published until June 2023. All statistical analysis was performed by STATA v.17. Our meta-analysis included 20 studies with 926 patients. We found that the combination therapy had a significantly lower rate of overall survival (OS) than SRS alone at 6-month 0.77[95%CI:0.74-0.85] for SRS alone and (100%) for SRS plus bevacizumab. At 1-year OS, 0.39 [95%CI: 0.32-0.47] for SRS alone and 0.61 [95%CI:0.44-0.77] for SRS plus bevacizumab (P-value:0.02). However, this advantage was not seen in the long term (18 months and two years). Additionally, the combination therapy had lower chances of progression-free survival (PFS) than SRS alone at the 6-month and 1-year time points, but the differences were insignificant. Our study indicates that incorporating bevacizumab with SRS may lead to a short-term increase in OS for rGBM patients but not long-term. Additionally, the PFS rate did not show significant improvement in the group receiving combination therapy. Further clinical trials are necessary to validate the enhanced overall survival with combination therapy for rGBM.

Headache Management in Individuals with Brain Tumor

Headache occurs commonly in individuals diagnosed with cerebral neoplasm. Though the features of a brain tumor-associated headache may vary, a progressive nature of headache and a change in headache phenotype from a prior primary headache disorder often are identified. Pathophysiologic mechanisms proposed for headache associated with brain tumor include headache related to traction on pain-sensitive structures, activation of central and peripheral pain processes, and complications from surgical, chemotherapeutic and/or radiotherapy treatment(s). Optimization of headache management is important for an individual's quality of life. Treatments are based upon patient-specific goals of care and may include tumor-targeted medical and surgical interventions, as well as a multimodal headache treatment approach incorporating acute and preventive medications, nutraceuticals, neuromodulation devices, behavioral interventions, anesthetic nerve blocks, and lifestyles changes.

Delayed Postoperative Intracerebral Hemorrhage Associated With Oral Multikinase Inhibitor Therapy for Cancer: A Case Report

Regorafenib is a multikinase inhibitor with anti-vascular endothelial growth factor receptor (VEGF) activity used as an antiangiogenic agent for metastatic colorectal cancer treatment and has been studied as a potential therapeutic agent for several other cancer treatments. Adverse reactions commonly reported with the use of regorafenib and similar oral multikinase inhibitors include hemorrhage, gastrointestinal fistulas, hypertension, and incomplete wound healing. We report a case of a 59-year-old man with metastatic colorectal adenocarcinoma post-colostomy on regorafenib treatment presenting to the emergency department with altered mental status. MRI showed a left frontoparietal mass, which was resected with a left frontal craniotomy. Postoperative MRI showed a resection cavity without significant hemorrhage. He had been prescribed regorafenib preceding his hospitalization, which was continued after admission before surgery and on postoperative day 1. Thirty-two hours after surgery, the patient exhibited sudden right-sided facial droop and right arm weakness. Imaging revealed an acute intraparenchymal hemorrhage within and adjacent to the tumor resection bed, which was managed conservatively. The patient was subsequently discharged to an inpatient rehabilitation facility. The unusual timing of the hemorrhage suggests that the hemorrhage was due to adverse effects of regorafenib. Patients undergoing neurosurgery should have regorafenib discontinued in preparation for surgery. Similar management should be considered for other anti-VEGF medications to avoid serious complications.

Emergency department imaging utilization of cancer patients treated with bevacizumab: single-institution 8-year experience

PURPOSE

This study aims to highlight the presentations, imaging, and clinical outcomes of cancer patients presenting to the emergency department (ED) while receiving bevacizumab (Avastin) therapy.

METHODS

Our retrospective study was based on data from a single institution to identify cancer patients who presented acutely to the ED between 2014 and 2021 within 3 months of beginning bevacizumab who subsequently received diagnostic imaging with CT, MRI, ultrasound, and/or nuclear medicine ventilation/perfusion (VQ) scans. Data gathered included presenting symptoms grouped by body system, imaging impressions, and clinical outcomes, including hospitalization and discontinuation of bevacizumab after each ED visit. Imaging examinations and patient charts were reviewed by a team of fellowship-trained radiologists, radiology residents, and medical students.

RESULTS

A total of 84 patients who presented to the ED were included for analysis. This included 32 (38.1%) males and 52 (61.9%) females, with a mean age of 61.2 years and an age range of 29-91 years. Neurological symptoms were the most common presenting symptoms, followed by abdominal symptoms and respiratory symptoms. Head imaging with CT and MRI was the most common imaging ordered with 55 total examinations, followed by abdominal imaging with 37 CT abdomen/pelvis (A/P) examinations, and then CT chest imaging with 22 examinations. Imaging revealed a serious adverse drug reaction in 21 (25.0%) patients, disease progression in 19 (22.6%), and no acute imaging findings in 44 (52.4%) patients. Imaging diagnoses were significantly associated with treatment planning, with a positive determination of bevacizumab-related serious adverse reaction on imaging leading to discontinuation of bevacizumab (p = 0.001).

CONCLUSION

Multimodality imaging was a commonly used assessment tool for cancer patients receiving bevacizumab who presented to the ED. Imaging played a crucial role in diagnosis in these patients, especially of treatment-related serious adverse reactions and disease progression. Positive imaging findings of serious adverse reactions affected patient management including discontinuation of bevacizumab.

Diagnosis and management of complications from the treatment of primary central nervous system tumors in adults

Central nervous system (CNS) tumor patients commonly undergo multimodality treatment in the course of their disease. Adverse effects and complications from these interventions have not been systematically studied, but pose significant challenges in clinical practice and impact function and quality of life, especially in the management of long-term brain tumor survivors. Here, the European Association of Neuro-Oncology (EANO) has developed recommendations to prevent, diagnose, and manage adverse effects and complications in the adult primary brain CNS tumor (except lymphomas) patient population with a specific focus on surgery, radiotherapy, and pharmacotherapy. Specifically, we also provide recommendations for dose adaptations, interruptions, and reexposure for pharmacotherapy that may serve as a reference for the management of standard of care in clinical trials. We also summarize which interventions are unnecessary, inactive or contraindicated. This consensus paper should serve as a reference for the conduct of standard therapy within and outside of clinical trials.

An insight into the risk factors of brain tumors and their therapeutic interventions

Brain tumors are an abnormal growth of cells in the brain, also known as multifactorial groups of neoplasm. Incidence rates of brain tumors increase rapidly, and it has become a leading cause of tumor related deaths globally. Several factors have potential risks for intracranial neoplasm. To date, the International Agency for Research on Cancer has classified the ionizing radiation and the N-nitroso compounds as established carcinogens and probable carcinogens respectively. Diagnosis of brain tumors is based on histopathology and suitable imaging techniques. Labeled amino acids and fluorodeoxyglucose with or without contrast-enhanced MRI are used for the evaluation of tumor traces. T2-weighted MRI is an advanced diagnostic implementation, used for the detection of low-grade gliomas. Treatment decisions are based on tumor size, location, type, patient's age and health status. Conventional therapeutic approaches for tumor treatment are surgery, radiotherapy and chemotherapy. While the novel strategies may include targeted therapy, electric field treatments and vaccine therapy. Inhibition of cyclin-dependent kinase inhibitors is an attractive tumor mitigation strategy for advanced-stage cancers; in the future, it may prove to be a useful targeted therapy. The blood-brain barrier poses a major hurdle in the transport of therapeutics towards brain tissues. Moreover, nanomedicine has gained a vital role in cancer therapy. Nano drug delivery system such as liposomal drug delivery has been widely used in the cancer treatment. Liposome encapsulated drugs have improved therapeutic efficacy than free drugs. Numerous treatment therapies for brain tumors are in advanced clinical research.

Outcomes of salvage fractionated re-irradiation combined with bevacizumab for recurrent high-grade gliomas that progressed after bevacizumab treatment*

BACKGROUND

There is no standard treatment for patients with recurrent high-grade gliomas who progress after bevacizumab treatment. We evaluated the outcomes of re-irradiation combined with bevacizumab for patients refractory to bevacizumab.

METHODS

Between January 2015 and September 2019, patients with progression after bevacizumab treatment were treated with re-irradiation combined with bevacizumab (25 Gy in five fractions).

RESULTS

Fourteen patients [glioblastoma, isocitrate dehydrogenase (IDH) wild type (N = 6), glioblastoma, IDH mutant (N = 4), anaplastic astrocytoma, IDH wild type (N = 1), anaplastic astrocytoma, IDH mutant (N = 1), glioblastoma, not otherwise specified (N = 1) and radiologically diagnosed brainstem glioma (N = 1)] were included in this study. The median survival and progression-free survival times after re-irradiation combined with bevacizumab were 6.1 and 3.8 months, respectively. The 6-month survival and progression-free survival rates were 54.5 and 15.7%, respectively. Patients with a Karnofsky performance status of ≥70 tended to have longer median survival time (9.3 vs. 5.4 months, respectively; P = 0.058) and had a significantly longer median progression-free survival time (4.2 vs. 3.7 months, respectively; P = 0.046) than those with a Karnofsky performance status of <70. Four patients (28.6%) achieved a complete or partial radiological response, and three patients (21.4%) had an improved Karnofsky performance status after re-irradiation combined with bevacizumab. Grade 3/4 toxicities included leukopenia in four patients (28.6%), hypertension in three (21.4%), proteinuria in one (7.1%) and gastrointestinal hemorrhage in one (7.1%).

CONCLUSIONS

Re-irradiation combined with bevacizumab for patients with recurrent high-grade gliomas who progress after bevacizumab treatment was feasible. Re-irradiation combined with bevacizumab is a potential treatment option, especially for patients with a Karnofsky performance status of ≥70.

Brain metastasis models: What should we aim to achieve better treatments?

Brain metastasis is emerging as a unique entity in oncology based on its particular biology and, consequently, the pharmacological approaches that should be considered. We discuss the current state of modelling this specific progression of cancer and how these experimental models have been used to test multiple pharmacologic strategies over the years. In spite of pre-clinical evidences demonstrating brain metastasis vulnerabilities, many clinical trials have excluded patients with brain metastasis. Fortunately, this trend is getting to an end given the increasing importance of secondary brain tumors in the clinic and a better knowledge of the underlying biology. We discuss emerging trends and unsolved issues that will shape how we will study experimental brain metastasis in the years to come.

Operative and peri-operative considerations in the management of brain metastasis

The number of patients who develop metastatic brain lesions is increasing as the diagnosis and treatment of systemic cancers continues to improve, resulting in longer patient survival. The role of surgery in the management of brain metastasis (BM), particularly multiple and recurrent metastases, remains controversial and continues to evolve. However, with appropriate patient selection, outcomes after surgery are typically favorable. In addition, surgery is the only means to obtain a tissue diagnosis and is the only effective treatment modality to quickly relieve neurological complications or life-threatening symptoms related to significant mass effect, CSF obstruction, and peritumoral edema. As such, a thorough understanding of the role of surgery in patients with metastatic brain lesions, as well as the factors associated with surgical outcomes, is essential for the effective management of this unique and growing patient population.

A multicenter real-world study of bevacizumab in heavily pretreated malignant gliomas: clinical benefit is a plausible end point?

Aim: This multicenter, retrospective study evaluates the clinical benefit (CB) of bevacizumab, alone or in combination, in recurrent gliomas (RG). Patients & methods: The CB was measured as a reduction of corticosteroid dosage and an improvement ≥20 points in the Karnofsky Performance Status lasting ≥3 months. Results: We collected data of 197 RG patients. A CB was observed in 120, patients without significant differences between patients treated with bevacizumab alone or in combination. The rate of patients who achieved a CB and free from progression at 1 year was 21.5 versus 1.4% in patients who did not report CB. Conclusion: The majority of RG patients treated with bevacizumab reported CB. Moreover, patients with CB showed improved survival.

Molecular mechanisms underlying cardiotoxicity of novel cancer therapeutics

Novel cancer therapeutics contribute to a steadily declining cancer mortality. However, several of these new therapies target pathways also involved in the cardiovascular system thus causing cardiotoxic side effects such as chemotherapy-induced heart failure (CIHF). This might limit the applicability of these effective treatments in a relevant number of patients. Furthermore, given the improving cancer survival rates, chemotherapy-induced cardiotoxic complications receive increasing attention given their potential impact on long-term morbidity and mortality. The understanding of molecular mechanisms that underlie CIHF is crucial for future improvement of pharmacodynamics of these therapeutics but also for developing specific interventions to prevent CIHF. Here, we discuss molecular mechanisms underlying CIHF of novel cancer therapeutics including a short synopsis on clinical management of patients suffering from CIHF.

Therapeutic Monoclonal Antibodies Delivery for the Glioblastoma Treatment

Glioblastoma multiforme (GBM) is the most common and challenging primary malignant brain tumor, being the median overall survival between 10 and 14 months due to its invasive characteristics. GBM treatment is mainly based on the maximal surgical resection and radiotherapy associated to chemotherapy. Monoclonal antibodies (mAbs) have been used in chemotherapy protocols for GBM treatment in order to improve immunotherapy and antiangiogenic processes. High specificity and affinity of mAbs for biological targets make them highly used for brain tumor therapy. Specifically, antiangiogenic mAbs have been wisely indicated in chemotherapy protocols because GBM is the most vascularized tumors in humans with high expression of cytokines. However, mAb-based therapy is not that effective due to the aggressive spread of the tumor associated to the difficulty in the access of mAb into the brain (due to the blood-brain barrier). For that reason, nanobiotechnology has played an important role in the treatment of several tumors, mainly in the tumors of difficult access, such as GBM. In this chapter will be discussed strategies related with nanobiotechnology applied to the mAb delivery and how these therapeutics can improve the GBM treatment and life quality of the patient.

[Hypofractionated radiotherapy for glioblastoma: changing the radiation treatment paradigm]

Hypofractionation has the dual advantage of increased cell death with a higher dose per fraction and a reduced effect of accelerated tumor cell repopulation due to a shorter overall treatment time. However, the potential advantage may be offset by increased toxicity in the late-responding neural tissues. Recently, investigators have attempted delivering radical doses of HFRT by escalating the dose in the immediate vicinity of the enhancing tumor and postoperative surgical cavity and reported reasonable outcomes with acceptable toxicity levels. Three different studies of high-dose HFRT have reported on the paradoxical phenomenon of improved survival in patients developing radiation necrosis at the primary tumor site. The toxicity criteria of RTOG and EORTC have defined clinically or radiographically suspected radionecrosis as Grade 4 toxicity. However, most patients diagnosed with radiation necrosis in the above studies remained asymptomatic. Furthermore, the probable association with improved survival would strongly argue against adopting a blind approach for classifying radiation necrosis as Grade 4 toxicity. The data emerging from the above studies is encouraging and strongly argues for further research. However, the majority of these studies are predominantly retrospective or relatively small single-arm prospective series that add little to the overall quality of evidence. Notwithstanding the above limitations, HFRT appears to be a safe and feasible strategy for glioblastoma patients.

Adjuvant Radiation Therapy and Temozolomide in Gliosarcoma: Is It Enough? Case Series of Seven Patients

Objective:

We present our experience of gliosarcoma (GSM) in oncology tertiary care center over the last 5 years.

Materials and Methods:

We carried out a retrospective analysis of seven patients with GSM diagnosed between April 2008 and December 2012. Demographic data, clinicopathological data, treatment strategies employed, details of recurrence, and survival patterns were reviewed.

Results:

The median age at diagnosis was 54 years, ranging between 34 and 63 years with a female predominance (57.1% females). Headache and neurological deficit were the most common symptoms with parietal region being the most common site of lesion. Subtotal resection followed by concurrent chemoradiation therapy was delivered to six patients. The results following completion of planned schedule of concurrent chemoradiotherapy were quite disappointing with two patients having no evidence of disease, one patient was lost to follow-up, and other three had progressive disease. One patient with progressive disease subsequently received eight cycles of bevacizumab on a clinical trial protocol. Fifteen-month posttreatment, she had stable disease on follow-up.

Conclusions:

Our experience suggests that despite treatment, the diagnosis of GSM portends a poor prognosis and the use of bevacizumab could represent a treatment approach to improve outcome in these patients. Although the role of targeted therapy in GSM remains unclear because of paucity of experience, the treatment decision should be according to patient's performance status, ability, and willingness to receive additional treatment.

Aptamers and Glioblastoma: Their Potential Use for Imaging and Therapeutic Applications

Glioblastoma is a highly aggressive primary brain tumour, renowned for its infiltrative growth and varied genetic profiles. The current treatment options are insufficient, and their off-target effects greatly reduce patient quality of life. The major challenge in improving glioblastoma diagnosis and treatment involves the development of a targeted imaging and drug delivery platform, capable of circumventing the blood brain barrier and specifically targeting glioblastoma tumours. The unique properties of aptamers demonstrate their capability of bridging the gap to the development of successful diagnosis and treatment options, where antibodies have previously failed. Aptamers possess many characteristics that make them an ideal novel imaging and therapeutic agent for the treatment of glioblastoma and other brain malignancies, and are likely to provide patients with a better standard of care and improved quality of life. Their target sensitivity, selective nature, ease of modification and low immunogenicity make them an ideal drug-delivery platform. This review article summarises the aptamers previously generated against glioblastoma cells or its identified biomarkers, and their potential application in diagnosis and therapeutic targeting of glioblastoma tumours.

Nanoparticulate Tetrac Inhibits Growth and Vascularity of Glioblastoma Xenografts

Thyroid hormone as L-thyroxine (T₄) stimulates proliferation of glioma cells in vitro and medical induction of hypothyroidism slows clinical growth of glioblastoma multiforme (GBM). The proliferative action of T₄ on glioma cells is initiated nongenomically at a cell surface receptor for thyroid hormone on the extracellular domain of integrin αvβ3. Tetraiodothyroacetic acid (tetrac) is a thyroid hormone derivative that blocks T₄ action at αvβ3 and has anticancer and anti-angiogenic activity. Tetrac has been covalently bonded via a linker to a nanoparticle (Nanotetrac, Nano-diamino-tetrac, NDAT) that increases the potency of tetrac and broadens the anticancer properties of the drug. In the present studies of human GBM xenografts in immunodeficient mice, NDAT administered daily for 10 days subcutaneously as 1 mg tetrac equivalent/kg reduced tumor xenograft weight at animal sacrifice by 50%, compared to untreated control lesions (p < 0.01). Histopathological analysis of tumors revealed a 95% loss of the vascularity of treated tumors compared to controls at 10 days (p < 0.001), without intratumoral hemorrhage. Up to 80% of tumor cells were necrotic in various microscopic fields (p < 0.001 vs. control tumors), an effect attributable to devascularization. There was substantial evidence of apoptosis in other fields (p < 0.001 vs. control tumors). Induction of apoptosis in cancer cells is a well-described quality of NDAT. In summary, systemic NDAT has been shown to be effective by multiple mechanisms in treatment of GBM xenografts.

Problems of Glioblastoma Multiforme Drug Resistance

Glioblastoma multiforme (GBL) is the most common and aggressive brain neoplasm. A standard therapeutic approach for GBL involves combination therapy consisting of surgery, radiotherapy, and chemotherapy. The latter is based on temozolomide (TMZ). However, even by applying such a radical treatment strategy, the mean patient survival time is only 14.6 months. Here we review the molecular mechanisms underlying the resistance of GBL cells to TMZ including genetic and epigenetic mechanisms. Present data regarding a role for genes and proteins MGMT, IDH1/2, YB-1, MELK, MVP/LRP, MDR1 (ABCB1), and genes encoding other ABC transporters as well as Akt3 kinase in developing resistance of GBL to TMZ are discussed. Some epigenetic regulators of resistance to TMZ such as microRNA and EZH2 are reviewed.

Carboxyethylpyrroles: From Hypothesis to the Discovery of Biologically Active Natural Products

Our research on the roles of lipid oxidation in human disease is guided by chemical intuition. For example, we postulated that 2-(ω-carboxyethyl)pyrrole (CEP) derivatives of primary amines would be produced through covalent adduction of a γ-hydroxyalkenal generated, in turn, through oxidative fragmentation of docosahexaenoates. Our studies confirmed the natural occurrence of this chemistry, and the biological activities of these natural products and their extensive involvements in human physiology (wound healing) and pathology (age-related macular degeneration, autism, atherosclerosis, sickle cell disease, and tumor growth) continue to emerge. This perspective recounts these discoveries and proposes new frontiers where further developments are likely. Perhaps more significantly, it depicts an effective chemistry-based approach to the discovery of novel biochemistry.

Addition of Anti-Angiogenetic Therapy with Bevacizumab to Chemo- and Radiotherapy for Leptomeningeal Metastases in Primary Brain Tumors

Leptomeningeal dissemination of a primary brain tumor is a condition which is challenging to treat, as it often occurs in rather late disease stages in highly pretreated patients. Its prognosis is dismal and there is still no accepted standard of care. We report here a good clinical effect with a partial response in three out of nine patients and a stable disease with improvement on symptoms in two more patients following systemic anti-angiogenic treatment with bevacizumab (BEV) alone or in combination with chemo- and/or radiotherapy in a series of patients with leptomeningeal dissemination from primary brain tumors (diffuse astrocytoma WHO°II, anaplastic astrocytoma WHO°III, anaplastic oligodendroglioma WHO°III, primitive neuroectodermal tumor and glioblastoma, both WHO°IV). This translated into effective symptom control in five out of nine patients, but only moderate progression-free and overall survival times were reached. Partial responses as assessed by RANO criteria were observed in three patients (each one with anaplastic oligodendroglioma, primitive neuroectodermal tumor and glioblastoma). In these patients progression-free survival (PFS) intervals of 17, 10 and 20 weeks were achieved. In three patients (each one with diffuse astrocytoma, anaplastic astrocytoma and primitive neuroectodermal tumor) stable disease was observed with PFS of 13, 30 and 8 weeks. Another three patients (all with glioblastoma) were primary non-responders and deteriorated rapidly with PFS of 3 to 4 weeks. No severe adverse events were seen. These experiences suggest that the combination of BEV with more conventional therapy schemes with chemo- and/or radiotherapy may be a palliative treatment option for patients with leptomeningeal dissemination of brain tumors.

Bevacizumab is superior to Temozolomide in causing mitochondrial dysfunction in human brain tumors

OBJECTIVE

Current chemotherapy treatments available for treating high-grade brain tumors, Temozolomide (TMZ) or Bevacizumab (BEV), not only have specific anti-tumor mechanisms, but also have an effect on mitochondria. However, effects of both drugs on mitochondria isolated from human brain tumors have not been thoroughly investigated. This study determined the direct effects of TMZ and BEV as well as the neurotoxic condition (calcium overload), on the function of mitochondria and compared these effects on mitochondria isolated from low- and high-grade human brain tumors.

METHODS

Mitochondria were isolated from either low- or high-grade human primary brain tumors. Calcium overload conditions (100 or 200 μM), TMZ (300 μM), and BEV (2 mg/mL) were applied to isolated mitochondria from low- and high-grade brain tumors. Following the treatment, mitochondrial function, including reactive oxygen species production, membrane potential changes, and swelling, were determined. The mitochondrial morphology was also examined.

RESULTS

In calcium overload conditions, mitochondrial dysfunction was only found to have occurred in low-grade tumors. In TMZ and BEV treatment, BEV, rather than TMZ, caused greater membrane depolarization and mitochondrial swelling in both grades of brain tumors.

CONCLUSIONS

TMZ and BEV can directly cause the dysfunction of mitochondria isolated from human brain tumors. However, BEV has a greater ability to disturb mitochondrial function in mitochondria isolated from human brain tumors than either TMZ or calcium overload conditions.

Leakage decrease detected by dynamic susceptibility-weighted contrast-enhanced perfusion MRI predicts survival in recurrent glioblastoma treated with bevacizumab

BACKGROUND AND PURPOSE

In glioblastoma, tumor progression appears to be triggered by expression of VEGF, a regulator of blood vessel permeability. Bevacizumab is a monoclonal antibody that inhibits angiogenesis by clearing circulating VEGF, resulting in a decline in the contrast-enhancing tumor, which does not always correlate with treatment response. Our objectives were: (1) to evaluate whether changes in DSC perfusion MRI-derived leakage could predict survival in recurrent glioblastoma, and (2) to estimate whether leakage at baseline was related to treatment outcome.

MATERIALS AND METHODS

We retrospectively analyzed DSC perfusion MRI in 24 recurrent glioblastomas treated with bevacizumab as second line chemotherapy. Leakage at baseline and changes in maximum leakage between baseline and the first follow-up after treatment were selected for quantitative analysis. Survival univariate analysis was made constructing survival curves using Kaplan-Meier method and comparing subgroups by log rank probability test.

RESULTS

Leakage reduction at 8 weeks after initiation of bevacizumab treatment had a significant influence on overall survival (OS) and progression-free survival (PFS). Median OS and PFS were 2.4 and 2.8 months longer for patients with leakage reduction at the first follow-up. Higher leakage at baseline was associated with leakage reduction after treatment. Odds ratio of treatment response was 9 for patients with maximum leakage at baseline >5.

CONCLUSIONS

Leakage decrease may predict OS and PFS in recurrent glioblastomas treated with bevacizumab. Leakage reduction postulates as a potential biomarker for treatment response evaluation. Leakage at baseline seems to predict response to treatment, but was not independently associated with survival.

Low-dose bevacizumab induces radiographic regression of vestibular schwannomas in neurofibromatosis type 2: A case report and literature review

The current case study aimed to explore the efficacy of a low-dose bevacizumab regimen in inhibiting tumor growth and minimizing adverse effects. A 55-year-old man with neurofibromatosis type 2 (NF2) suffered bilateral vestibular schwannomas (VS) measuring 5.25 and 2.54 cm³ on the left and right, respectively. His capacity for bilateral language recognition was impaired. However, the patient refused microsurgical tumor resection and gamma knife therapy. Low-dose bevacizumab regimen (3.3–2.2 mg/kg every 2–4 weeks) was administered by intravenous injection for ~1.5 years to inhibit tumor growth and avoid further deterioration of hearing. Compared with baseline measurements prior to treatment, the bilateral VS regressed to 3.59 cm³ (68%) and 2.08 cm³ (82%) on the left and right, respectively. No hearing improvement was detected; however, the patient subjectively experienced a significant hearing improvement as his ability to communicate with people and distinguish voices was restored. No adverse effects were observed. Bevacizumab provides an alternative treatment option for those who refuse surgical intervention. Given the adverse effects commonly induced by bevacizumab, the use of a low-dose regimen would appear to be promising with regard to tumor regression and hearing preservation for patients with VS in NF2. However, the minimum dose required to sustain a response to bevacizumab in NF2 patients remains unknown. Finding the minimum effective dose sufficient to sustain hearing and/or volumetric response for individual patients is required.

New perspectives in glioblastoma antiangiogenic therapy

Glioblastoma (GB) is highly vascularised tumour, known to exhibit enhanced infiltrative potential. One of the characteristics of glioblastoma is microvascular proliferation surrounding necrotic areas, as a response to a hypoxic environment, which in turn increases the expression of angiogenic factors and their signalling pathways (RAS/RAF/ERK/MAPK pathway, PI3K/Akt signalling pathway and WTN signalling cascade). Currently, a small number of anti-angiogenic drugs, extending glioblastoma patients survival, are available for clinical use. Most medications are ineffective in clinical therapy of glioblastoma due to acquired malignant cells or intrinsic resistance, angiogenic receptors cross-activation and redundant intracellular signalling, or the inability of the drug to cross the blood-brain barrier and to reach its target in vivo. Researchers have also observed that GB tumours are different in many aspects, even when they derive from the same tissue, which is the reason for personalised therapy. An understanding of the molecular mechanisms regulating glioblastoma angiogenesis and invasion may be important in the future development of curative therapeutic approaches for the treatment of this devastating disease.

Bevacizumab for glioblastoma

Individuals with glioblastoma are often characterized by older age, advanced neurologic manifestations at the primary stage, and unresectable tumors, and these factors are associated with poor treatment outcomes. Administration of bevacizumab (BV, Avastin^®) promotes tumor regression and improves cerebral edema, and is expected to improve neurologic findings in many patients with malignant gliomas, including glioblastoma. Although the addition of BV to the conventional standard therapy (chemoradiotherapy with temozolomide) for newly diagnosed glioblastoma prolonged the progression-free survival time and the performance status of patients, it failed to extend overall survival time. However, more than 50% of glioblastoma patients show Karnofsky performance status ≤70 at initial presentation; therefore, BV should be used to improve or maintain their performance status as an initial treatment. Most of the adverse events of BV, except hypertension and proteinuria, occur as complications of glioblastoma, and explanation of the advantages and disadvantages of BV administration to patients is important. Herein, the efficacy, safety, and challenges of using BV for treating glioblastoma were reviewed.

A novel engineered VEGF blocker with an excellent pharmacokinetic profile and robust anti-tumor activity

BACKGROUND

Relatively poor penetration and retention in tumor tissue has been documented for large molecule drugs including therapeutic antibodies and recombinant immunoglobulin constant region (Fc)-fusion proteins due to their large size, positive charge, and strong target binding affinity. Therefore, when designing a large molecular drug candidate, smaller size, neutral charge, and optimal affinity should be considered.

METHODS

We engineered a recombinant protein by molecular engineering the second domain of VEGFR1 and a few flanking residues fused with the Fc fragment of human IgG1, which we named HB-002.1. This recombinant protein was extensively characterized both in vitro and in vivo for its target-binding and target-blocking activities, pharmacokinetic profile, angiogenesis inhibition activity, and anti-tumor therapeutic efficacy.

RESULTS

HB-002.1 has a molecular weight of ~80 kDa, isoelectric point of ~6.7, and an optimal target binding affinity of <1 nM. The pharmacokinetic profile was excellent with a half-life of 5 days, maximal concentration of 20.27 μg/ml, and area under the curve of 81.46 μg·days/ml. When tested in a transgenic zebrafish embryonic angiogenesis model, dramatic inhibition in angiogenesis was exhibited by a markedly reduced number of subintestinal vessels. When tested for anti-tumor efficacy, HB-002.1 was confirmed in two xenograft tumor models (A549 and Colo-205) to have a robust tumor killing activity, showing a percentage of inhibition over 90% at the dose of 20 mg/kg. Most promisingly, HB-002.1 showed a superior therapeutic efficacy compared to bevacizumab in the A549 xenograft model (tumor inhibition: 84.7% for HB-002.1 versus 67.6% for bevacizumab, P<0.0001).

CONCLUSIONS

HB-002.1 is a strong angiogenesis inhibitor that has the potential to be a novel promising drug for angiogenesis-related diseases such as tumor neoplasms and age-related macular degeneration.

Unplanned readmissions and survival following brain tumor surgery

OBJECT

Research on readmissions has been influenced by efforts to reduce hospital cost and avoid penalties stipulated by the Centers for Medicare and Medicaid Services. Less emphasis has been placed on understanding these readmissions and their impact on patient outcomes. This study 1) delineates reasons for readmission, 2) explores factors associated with readmissions, and 3) describes their impact on the survival of glioblastoma patients.

METHODS

The authors conducted a retrospective review of 362 cases involving patients with glioblastoma undergoing biopsy or tumor resection at their institution between 2003 and 2011. Reasons for re-hospitalization were characterized according to whether or not they were related to surgery and considered preventable. Multivariate analyses were conducted to identify the effect of readmission on survival and determine factors associated with re-hospitalizations.

RESULTS

Twenty-seven (7.5%) of 362 patients experienced unplanned readmissions within 30 days of surgery. Six patients (22.2%) were readmitted by Day 7, 14 (51.9%) by Day 14, and 20 (74.1%) by Day 21. Neurological, infectious, and thromboembolic complications were leading reasons for readmission, accounting for, respectively, 37.0%, 29.6%, and 22.2% of unplanned readmissions. Twenty-one (77.8%) of the 27 readmissions were related to surgery and 19 (70.4%) were preventable. The adjusted hazard ratio of mortality associated with a readmission was 2.03 (95% CI 1.3-3.1). Higher-functioning patients (OR 0.96, 95% CI 0.9-1.0) and patients discharged home (OR 0.21, 95% CI 0.1-0.6) were less likely to get readmitted.

CONCLUSIONS

An overwhelming fraction of documented unplanned readmissions were considered preventable and related to surgery. Patients who were readmitted to the hospital within 30 days of surgery had twice the risk of mortality compared with patients who were not readmitted.

Efficacy of temozolomide and bevacizumab for the treatment of leptomeningeal dissemination of recurrent glioblastoma: A case report

The prognosis of leptomeningeal dissemination of recurrent glioblastoma is poor, and chemotherapy results in minimal palliative efficacy. Temozolomide (TMZ) is an established therapy for patients with malignant glioma and the standard of care in parenchymal gliomas; however, few reports have been published with regard to its use for the treatment of leptomeningeal dissemination. Only one report has indicated the radiographic response of leptomeningeal dissemination to a TMZ rechallenge, suggesting a potential causative effect. While bevacizumab is an effective therapy for recurrent glioblastoma, its effect on leptomeningeal dissemination of recurrent glioblastoma remains unclear. The present study reports a case of leptomeningeal dissemination of recurrent glioblastoma in which transient neurological and radiological improvement was observed following chemotherapy with TMZ and bevacizumab. However, five months after the diagnosis of leptomeningeal dissemination the patient succumbed to the disease.

New treatment modalities for brain tumors in dogs and cats

Despite advancements in standard therapies, intracranial tumors remain a significant source of morbidity and mortality in veterinary and human medicine. Several newer approaches are gaining more widespread acceptance or are currently being prepared for translation from experimental to routine therapeutic use. Clinical trials in dogs with spontaneous brain tumors have contributed to the development and human translation of several novel therapeutic brain tumor approaches.

Effective treatment of diverse medulloblastoma models with mebendazole and its impact on tumor angiogenesis

BACKGROUND

Medulloblastoma is the most common malignant brain tumor in children. Current standard treatments cure 40%-60% of patients, while the majority of survivors suffer long-term neurological sequelae. The identification of 4 molecular groups of medulloblastoma improved the clinical management with the development of targeted therapies; however, the tumor acquires resistance quickly. Mebendazole (MBZ) has a long safety record as antiparasitic in children and has been recently implicated in inhibition of various tyrosine kinases in vitro. Here, we investigated the efficacy of MBZ in various medulloblastoma subtypes and MBZ's impact on vascular endothelial growth factor receptor 2 (VEGFR2) and tumor angiogenesis.

METHODS

The inhibition of MBZ on VEGFR2 kinase was investigated in an autophosphorylation assay and a cell-free kinase assay. Mice bearing orthotopic PTCH1-mutant medulloblastoma allografts, a group 3 medulloblastoma xenograft, and a PTCH1-mutant medulloblastoma with acquired resistance to the smoothened inhibitor vismodegib were treated with MBZ. The survival benefit and the impact on tumor angiogenesis and VEGFR2 kinase function were analyzed.

RESULTS

We determined that MBZ interferes with VEGFR2 kinase by competing with ATP. MBZ selectively inhibited tumor angiogenesis but not the normal brain vasculatures in orthotopic medulloblastoma models and suppressed VEGFR2 kinase in vivo. MBZ significantly extended the survival of medulloblastoma models derived from different molecular backgrounds.

CONCLUSION

Our findings support testing of MBZ as a possible low-toxicity therapy for medulloblastomas of various molecular subtypes, including tumors with acquired vismodegib resistance. Its antitumor mechanism may be partially explained by inhibition of tumor angiogenesis.

Increased risk of cerebrovascular events in patients with cancer treated with bevacizumab: a meta-analysis

Arterial ischemia and hemorrhage are associated with bevacizumab, an inhibitor of vascular endothelial growth factor that is widely used to treat many types of cancers. As specific types of arterial ischemia and hemorrhage, cerebrovascular events such as central nervous system (CNS) ischemic events and CNS hemorrhage are serious adverse events. However, increased cerebrovascular events have not been uniformly reported by previous studies. New randomized controlled trials (RCTs) have been reported in recent years and we therefore conducted an up-to-date meta-analysis of RCTs to fully characterize the risk of cerebrovascular events with bevacizumab. We searched the databases of PubMed, Web of Science, and the American Society of Clinical Oncology conferences to identify relevant clinical trials up to February 2014. Eligible studies included prospective RCTs that directly compared patients with cancer treated with and without bevacizumab. A total of 12,917 patients from 17 RCTs were included in our analysis. Patients treated with bevacizumab had a significantly increased risk of cerebrovascular events compared with patients treated with control medication, with a relative risk of 3.28 (95% CI, 1.97-5.48). The risks of CNS ischemic events and CNS hemorrhage were increased compared with control, with RRs of 3.22 (95% CI, 1.71-6.07) and 3.09 (95% CI, 1.36-6.99), respectively. Risk varied with the bevacizumab dose, with RRs of 3.97 (95% CI, 2.15-7.36) and 1.96 (95% CI, 0.76-5.06) at 5 and 2.5 mg/kg/week, respectively. Higher risks were observed in patients with metastatic colorectal cancer (RR, 6.42; 95% CI, 1.76-35.57), and no significant risk was observed in other types of tumors. In conclusion, the addition of bevacizumab significantly increased the risk of cerebrovascular events compared with controls, including CNS ischemic events and CNS hemorrhage. The risk may vary with bevacizumab dose and tumor type.

Prolonged use of nimotuzumab in children with central nervous system tumors: safety and feasibility

Primary brain tumors constitute the most frequent solid tumor of childhood. High expression of the epidermal growth factor receptor (EGFR) protein has been associated with tumor progression and enhanced tumorigenicity in adult and children gliomas. Nimotuzumab is a humanized antibody that targets the EGFR and has proven efficacy in adult and children gliomas. To provide a new therapeutic option for patients with active, poor prognosis central nervous system (CNS) tumors and to evaluate the feasibility and safety of long-term nimotuzumab therapy in children with diverse CNS tumors, an expanded access program was launched at the Juan Manuel Marquez hospital. Patients were required to be 18 or younger and have one CNS tumor: low-grade glioma (LGG) or high-grade glioma (HGG), brainstem glioma (BSG), ependymoma or primitive neuroectodermal tumor (PNET), and a Lansky or Karnofsky performance status ≥40. Treatment consisted of weekly nimotuzumab administered at 150 mg/m(2) for 12 weeks, continuing every 14 days in the absence of severe condition worsening or unacceptable toxicity. Nimotuzumab was administered alone or in combination with radiotherapy, chemotherapy, or both, depending on the tumor type, stage, and previous treatment. Eighty-eight patients, 39 with BSG, 25 with HGG, 9 with progressive LGG, 9 with anaplastic ependymomas, and 6 with other tumor types, including PNET, neuroblastoma, meduloblastoma, and thalamic tumors, were treated with the antibody. The mean number of nimotuzumab doses was 36, from 1 to 108. The most frequent adverse events were mild to moderate skin rash, mucositis, vomiting, seizures, hypothermia, hyperthermia, and paleness. One patient had a grade 3 mucositis, while the other had a grade 3 bleeding on surgery. Sixteen children stopped treatment after at least 2 years with stable disease, partial or complete response. All children were able to maintain the best response achieved on treatment after a 3-year interruption. In summary, this study shows the feasibility of very prolonged administration of nimotuzumab together with the lack of rebound effect after treatment cessation.

Dexamethasone alleviates tumor-associated brain damage and angiogenesis

Children and adults with the most aggressive form of brain cancer, malignant gliomas or glioblastoma, often develop cerebral edema as a life-threatening complication. This complication is routinely treated with dexamethasone (DEXA), a steroidal anti-inflammatory drug with pleiotropic action profile. Here we show that dexamethasone reduces murine and rodent glioma tumor growth in a concentration-dependent manner. Low concentrations of DEXA are already capable of inhibiting glioma cell proliferation and at higher levels induce cell death. Further, the expression of the glutamate antiporter xCT (system X_c⁻; SLC7a11) and VEGFA is up-regulated after DEXA treatment indicating early cellular stress responses. However, in human gliomas DEXA exerts differential cytotoxic effects, with some human glioma cells (U251, T98G) resistant to DEXA, a finding corroborated by clinical data of dexamethasone non-responders. Moreover, DEXA-resistant gliomas did not show any xCT alterations, indicating that these gene expressions are associated with DEXA-induced cellular stress. Hence, siRNA-mediated xCT knockdown in glioma cells increased the susceptibility to DEXA. Interestingly, cell viability of primary human astrocytes and primary rodent neurons is not affected by DEXA. We further tested the pharmacological effects of DEXA on brain tissue and showed that DEXA reduces tumor-induced disturbances of the microenvironment such as neuronal cell death and tumor-induced angiogenesis. In conclusion, we demonstrate that DEXA inhibits glioma cell growth in a concentration and species-dependent manner. Further, DEXA executes neuroprotective effects in brains and reduces tumor-induced angiogenesis. Thus, our investigations reveal that DEXA acts pleiotropically and impacts tumor growth, tumor vasculature and tumor-associated brain damage.

The integrin antagonist, cilengitide, is a weak inhibitor of αIIbβ3 mediated platelet activation and inhibits platelet adhesion under flow

The RGD cyclic pentapetide, cilengitide, is a selective inhibitor of αvβ3 and αvβ5 integrins and was developed for antiangiogenic therapy. Since cilengitide interacts with platelet αIIbβ3 and platelets express αv integrins, the effect of cilengitide on platelet pro-coagulative response and adhesion is of interest. Flow-based adhesion assays were performed to evaluate platelet adhesion and rolling on von Willebrand factor (vWf), on fibrinogen and on human umbilical vein endothelial cells (HUVECs). Flow cytometry was used to detect platelet activation (PAC1) and secretion (CD62P) by cilengitide and light transmission aggregometry was used to detect cilengitide-dependent platelet aggregation. Cilengitide inhibited platelet adhesion to fibrinogen at concentrations above 250 µM [which is the Cmax in human studies] and adhesion to vWf and HUVECs at higher concentrations under physiologic flow conditions. Platelet aggregation was already impaired at cilengitide concentrations >10 µM. Activation of αIIbβ3 integrin was inhibited by 250 µM cilengitide, whereas platelet secretion was unaffected by cilengitide. No evidence of cilengitide-induced platelet activation was found at all tested concentrations (0.01-1500 µM). At higher concentrations, platelet activation was inhibited, predominantly due to αIIbβ3 inhibition.

Molecularly targeted drugs for metastatic colorectal cancer

The survival rate of patients with metastatic colorectal cancer (mCRC) has significantly improved with applications of molecularly targeted drugs, such as bevacizumab, and led to a substantial improvement in the overall survival rate. These drugs are capable of specifically targeting the inherent abnormal pathways in cancer cells, which are potentially less toxic than traditional nonselective chemotherapeutics. In this review, the recent clinical information about molecularly targeted therapy for mCRC is summarized, with specific focus on several of the US Food and Drug Administration-approved molecularly targeted drugs for the treatment of mCRC in the clinic. Progression-free and overall survival in patients with mCRC was improved greatly by the addition of bevacizumab and/or cetuximab to standard chemotherapy, in either first- or second-line treatment. Aflibercept has been used in combination with folinic acid (leucovorin)-fluorouracil-irinotecan (FOLFIRI) chemotherapy in mCRC patients and among patients with mCRC with wild-type KRAS, the outcomes were significantly improved by panitumumab in combination with folinic acid (leucovorin)-fluorouracil-oxaliplatin (FOLFOX) or FOLFIRI. Because of the new preliminary studies, it has been recommended that regorafenib be used with FOLFOX or FOLFIRI as first- or second-line treatment of mCRC chemotherapy. In summary, an era of new opportunities has been opened for treatment of mCRC and/or other malignancies, resulting from the discovery of new selective targeting drugs.