Humanized anti-VEGF Antibody Research Articles

Effect of Intravitreal Anti-Vascular Growth Factor Agents With or Without Macular Photocoagulation on Diabetic Macular Edema: A Systematic Review and Meta-Analysis.

IntroductionDiabetes is a common cause of new sight loss in populations world-wide, and diabetic macular edema (DME) is a major cause of visual deficits in the diabetic populations of developed countries. We have performed a meta-analysis to evaluate whether combined treatment with anti-vascular endothelial growth factor (VEGF) injections and macular photocoagulation (MPC) is more efficacious than primary monotherapy with anti-VEGF injections in patients with DME.MethodsWe systematically searched the PubMed and Web of Science databases for studies providing sufficient information for a comparison of pre- and post-treatment of central macular thickness (CMT) and best-corrected visual acuity (BCVA) between two groups of patients with DME given interventional therapies (monotherapy with an anti-VEGF agent vs. combination therapy with an anti-VEGF agent and MPC) before January 2019. A meta-analysis was performed to summarize the results of the studies included in the systematic review.ResultsThe results of our meta-analysis indicated that post-treatment CMT was significantly lower at 3 months in DME patients receiving combination therapy with bevacizumab, a humanized anti-VEGF antibody, and MPC than in those receiving monotherapy with bevacizumab. The results also showed that post-treatment CMT was lower in DME patients given ranibizumab, an anti-VEGF agent, in combination with MPC at 6, 9 and 12 months than in those treated with ranibizumab alone. However, no significant differences were found in post-treatment BCVA at 1, 3, 6, 9 and 12 months between DME patients receiving combination therapy with an anti-VEGF agent (bevacizumab or ranibizumab) and MPC and those receiving monotherapy with an anti-VEGF agent.ConclusionIn conclusion, the results of our meta-analysis demonstrate a transiently synergistic effect of MPC on CMT when this treatment is combined with anti-VEGF agents, whereas no similar synergistic effect could be detected on the BCVA. A relatively longer follow-up was essential to be able to evaluate the long-term existence of this synergistic effect.Electronic Supplementary MaterialThe online version of this article (10.1007/s13300-019-0631-5) contains supplementary material, which is available to authorized users.

Malignant peritoneal mesothelioma: a review.

Malignant peritoneal mesothelioma (MPM) is a very rare malignancy of the peritoneum and has a poor prognosis. Of all mesotheliomas, pleural mesothelioma is more common than MPM. In comparison to pleural mesothelioma, the link with asbestos exposure is weaker (33-50% vs. >80%), but it is still the best-defined risk factor. MPM spreads predominantly expansive rather than infiltrative and symptoms are related to tumor spread within the abdominal cavity. Often, MPM is encountered incidentally by diagnostic imaging or by surgery. Computed tomography scan is widely accepted as a first line modality in diagnostic imaging. In diagnostic histopathology, MPM presents some challenges. Firstly, adequate clinical information is of utmost importance to consider the possibility of the diagnosis of MPM. Furthermore, a few morphological subtypes and variants exist. The most sensitive immunohistochemical markers are calretinin (100%), WT1 (94%) and CK5/6 (89%). The malignant character of immunohistochemically demonstrated mesothelial cells is not always obvious. This paradigm somewhat changed with the advent of immunohistochemical demonstration of BAP1 (BRCA-1 associated protein 1). Loss of BAP1 expression supports a diagnosis of malignancy. The gold standard in treatment remains cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC). Targetable molecular pathways in MPM are being identified. An exciting finding was the demonstration of ALK rearrangements in a small subset of patients with MPM and it is hoped for that at least this small subgroup of patients could benefit from treatment with ALK inhibitors. First-generation tyrosine kinase inhibitors against epidermal growth factor receptor (EGFR) did not show any significant activity in MPM. In contrast, nintedanib, an angiokinase inhibitor, improved progression-free survival and bevacizumab, a humanized anti-VEGF antibody increased overall survival in patients with MPM, when administered in combination with cisplatin and pemetrexed. Ongoing immunotherapy trials will offer a possible new treatment.

Monitoring antiangiogenesis of bevacizumab in zebrafish.

Bevacizumab, which is a humanized anti-VEGF antibody, has been successfully applied in clinics since 2004. Bevacizumab in combination with chemotherapy showed high safety and has been applied to solid tumors. However, studies on the insight into the mechanism about the antiangiogenesis activity of bevacizumab were mostly done on mice models, and so there are no visual and intuitive models to observe the process of antiangiogenesis. Here, we first used a zebrafish model to investigate the angiogenesis suppressing behavior of bevacizumab. Our results showed that bevacizumab inhibited formation of zebrafish subintestinal veins, which mimics the process of tumor angiogenesis in vivo. Meanwhile, bevacizumab caused specific vasculature formation defects in subintestinal veins but not in the trunk. Our study also indicated that bevacizumab could inhibit zebrafish retinal angiogenesis with therapeutic potential.

Bevacizumab for malignant gliomas: current indications, mechanisms of action and resistance, and markers of response.

Vascular endothelial growth factor (VEGF) is an attractive target of antiangiogenic therapy in glioblastomas. Bevacizumab (Bev), a humanized anti-VEGF antibody, is associated with the improvement of progression-free survival and performance status in patients with glioblastoma. However, randomized trials uniformly suggest that these favorable clinical effects of Bev do not translate into an overall survival benefit. The mechanisms of action of Bev appear to include the inhibition of tumor angiogenesis, as well as indirect effects such as the depletion of niches for glioma stem cells and stimulation of antitumor immunity. Although several molecules/pathways have been reported to mediate adaptation and resistance to Bev, including the activation of alternative pro-angiogenic pathways, the resistance mechanisms have not been fully elucidated; for example, the mechanism that reinduces tumor hypoxia remains unclarified. The identification of imaging characteristics or biomarkers predicting the response to Bev, as well as the better understanding of the mechanisms of action and resistance, is crucial to improve the overall clinical outcome and optimize individual therapy. In this article, the authors review the results of important clinical trials/studies, the current understanding of the mechanisms of action and resistance, and the knowledge of imaging characteristics and biomarkers predicting the response to Bev.

Intravitreally Injected Anti-VEGF Antibody Reduces Brown Fat in Neonatal Mice.

Anti-vascular endothelial growth factor (VEGF) agents are the mainstay treatment for various angiogenesis-related retinal diseases. Currently, bevacizumab, a recombinant humanized anti-VEGF antibody, is trailed in retinopathy of prematurity, a vasoproliferative retinal disorder in premature infants. However, the risks of systemic complications after intravitreal injection of anti-VEGF antibody in infants are not well understood. In this study, we show that intravitreally injected anti-VEGF antibody is transported into the systemic circulation into the periphery where it reduces brown fat in neonatal C57BL/6 mice. A considerable amount of anti-VEGF antibody was detected in serum after intravitreal injection. Furthermore, in interscapular brown adipose tissue, we found lipid droplet accumulation, decreased VEGF levels, loss of vascular network, and decreased expression of mitochondria-related genes, Ppargc1a and Ucp1, all of which are characteristics of “whitening” of brown fat. With increasing age and body weight, brown fat restored its morphology and vascularity. Our results show that there is a transient, but significant impact of intravitreally administered anti-VEGF antibody on brown adipose tissue in neonatal mice. We suggest that more attention should be focused on the metabolic and developmental significance of brown adipose tissue in bevacizumab treated retinopathy of prematurity infants.

Angiogenesis and Anti-angiogenic Therapies in Epithelial Ovarian Cancer

Ovarian cancer has a poor prognosis even after a complete resection and a platinum adjuvant chemotherapy because of its high rate of relapses. Clinical research has shown the role of angiogenesis in the development and progression of ovarian carcinoma. Several factors are involved, specially the VEGF. Bevacizumab is a humanized anti-VEGF antibody that was approved by the European Medicines Agency in first line for the treatments of advanced epithelial ovarian cancer, fallopian tube cancer and primary peritoneal cancer. It has to be combined with carboplatin and paclitaxel followed by maintenance therapy with bevacizumab alone. Bevacizumab has also been approved by EMA for the treatment of platinum-sensitive ovarian cancer recurrence in combination with carboplatin and gemcitabine. This literature review aims to provide updates about angiogenesis in ovarian cancer, pro-and anti-angiogenic factors that regulate angiogenesis, and lists new anti-angiogenic therapies in different phases of clinical development that aim to improve survival in patients with ovarian cancer. Keywords: Angiogenesis, anti-angiogenic therapies, bevacizumab, ovarian cancer, VEGF.

Anti-VEGF antibodies mitigate the development of radiation necrosis in mouse brain.

To quantify the effectiveness of anti-VEGF antibodies (bevacizumab and B20-4.1.1) as mitigators of radiation-induced, central nervous system (brain) necrosis in a mouse model. Cohorts of mice were irradiated with single-fraction 50- or 60-Gy doses of radiation targeted to the left hemisphere (brain) using the Leksell Perfexion Gamma Knife. The onset and progression of radiation necrosis were monitored longitudinally by in vivo, small-animal MRI, beginning 4 weeks after irradiation. MRI-derived necrotic volumes for antibody (Ab)-treated and untreated mice were compared. MRI results were supported by correlative histology. Hematoxylin and eosin-stained sections of brains from irradiated, non-Ab-treated mice confirmed profound tissue damage, including regions of fibrinoid vascular necrosis, vascular telangiectasia, hemorrhage, loss of neurons, and edema. Treatment with the murine anti-VEGF antibody B20-4.1.1 mitigated radiation-induced changes in an extraordinary, highly statistically significant manner. The development of radiation necrosis in mice under treatment with bevacizumab (a humanized anti-VEGF antibody) was intermediate between that for B20-4.1.1-treated and non-Ab-treated animals. MRI findings were validated by histologic assessment, which confirmed that anti-VEGF antibody treatment dramatically reduced late-onset necrosis in irradiated brain. The single-hemispheric irradiation mouse model, with longitudinal MRI monitoring, provides a powerful platform for studying the onset and progression of radiation necrosis and for developing and testing new therapies. The observation that anti-VEGF antibodies are effective mitigants of necrosis in our mouse model will enable a wide variety of studies aimed at dose optimization and timing and mechanism of action with direct relevance to ongoing clinical trials of bevacizumab as a treatment for radiation necrosis.

Potent anti-angiogenesis and anti-tumor activity of a novel human anti-VEGF antibody, MIL60

Angiogenesis is crucial for tumor development, growth and metastasis. Vascular endothelial growth factor (VEGF) has been implicated in promoting solid tumor growth and metastasis via stimulating tumor-associated angiogenesis, and blocking the activity of VEGF can starve tumors. Avastin, which is a humanized anti-VEGF antibody, has been successfully applied in clinics since 2004. However, the price of Avastin is extremely high for Chinese people. Here, we report a novel human anti-VEGF neutralizing antibody, MIL60, which shows an affinity comparable to that of Avastin (the KD value of MIL60 was 44.5pM, while that of Avastin was 42.7pM). MIL60 displays favorable actions in inhibiting VEGF-triggered endothelial cell proliferation (the IC50 value of MIL60 was 31±6.4ng/ml and that of Avastin was 47±8.1ng/ml), migration (8µg/ml or 0.8µg/ml MIL60 versus the control: P<0.05) and tube formation (2µg/ml or 0.2µg/ml MIL60 versus the control: P<0.05) via the VEGFR2 signaling pathway. Moreover, MIL60 was shown to inhibit tumor growth and angiogenesis in vivo in xenograft models of human colon carcinoma and ovarian cancer using immunotherapy and immunohistochemistry analysis (MIL60 versus N.S.: P=0.0007; Avastin versus N.S.: P=0.00046). These data suggest that MIL60 is a potential therapeutic, anti-angiogenic agent. Our work provides a novel anti-VEGF antibody, which can be considered an anti-tumor antibody candidate and a new option for patients with various cancers.

807 Experimental Therapeutic Approach of Orthotopic and Subcutaneous Human Retinoblastoma Xenografts by the Human Anti-VEGF Antibody Bevacizumab, Alone or in Combination With Carboplatin

807 Experimental Therapeutic Approach of Orthotopic and Subcutaneous Human Retinoblastoma Xenografts by the Human Anti-VEGF Antibody Bevacizumab, Alone or in Combination With Carboplatin

The curative efficacy of namitecan (ST1968) in preclinical models of pediatric sarcoma is associated with antiangiogenic effects

Namitecan (ST1968), a novel hydrophilic camptothecin analog of the 7-oxyiminomethyl series, was selected for clinical development on the basis of its promising preclinical efficacy. Since there is clinical evidence of efficacy of camptothecins against pediatric tumors, this study was performed to explore the antitumor and antiangiogenic activity of the camptothecin derivative in pediatric sarcoma models. With the exception of an undifferentiated rhabdomyosarcoma (A204), namitecan exhibited curative efficacy even at well-tolerated suboptimal doses in a panel of five models. The good therapeutic index of namitecan likely reflected a high and persistent drug accumulation at tumor site. The four responsive tumors were characterized by high topoisomerase I expression. In the RD/TE-671 rhabdomyosarcoma model the drug activity was associated with a marked antiangiogenic effect, which was consistent with the downregulation of proangiogenic factors, including VEGF, bFGF and the multifunctional chemokines CCL-2 and CXCL16. In agreement with this modulation, the combination of low doses of namitecan with other antiangiogenic agents, such as bevacizumab (a humanized anti-VEGF antibody) and sunitinib (a multitarget tyrosine kinase inhibitor effective against receptors implicated in the angiogenesis process), enhanced the antitumor effects. In conclusion, this preclinical study provides evidence of curative efficacy of namitecan at well-tolerated doses against pediatric sarcoma models, likely reflecting a contribution of antiangiogenic effects. Based on the promising therapeutic profile, namitecan is a good candidate for clinical evaluation in pediatric sarcomas.

Brain cancer immunoediting: novel examples provided by immunotherapy of malignant gliomas

A number of studies in murine models have suggested that the immune system may edit different tumors by forcing their expression profiles so that they escape immune reactions and proliferate. Glioblastoma (GB), the most frequent and aggressive primary brain tumor, provides a good example of this, thanks to the production of numerous immunosuppressive molecules (with TGF-β being of paramount importance), downregulation of the MHC complex and deregulation of the potential for antigen presentation by the surrounding microglia. Given that surgery, radiotherapy and chemotherapy with available protocols have limited effects on the survival of GB patients, different immunotherapy strategies have been developed, based on the use of dendritic cells, antibodies and peptide vaccination. Presently, bevacizumab, a humanized anti-VEGF antibody, provides the most successful example for immune-based treatment of GB, however, its action is limited in time, as the often tumor relapses due to still undefined immunoediting mechanisms. Altered function of EGF receptor-driven pathways is common in GB and is most frequently due to the presence of a deleted form named EGFRvIII, providing a unique cancer epitope that has been targeted by immunotherapy. A recent trial of GB immunotherapy based on vaccination with the EGFRvIII peptide has shown clinical benefit: interestingly most GBs at relapse were negative for EGFRvIII expression, a relevant, direct example of cancer immunoediting. Investigations on the mechanisms of GB immunoediting will lead to an increased understanding of the biology of this malignancy and hopefully provide novel therapeutic targets.

Cooperative Inhibitory Effect Of Bevacizumab And Nutlin-3a on Tumor Growth, Angiogenesis, And Metastasis In An Experimental Model Of Neuroblastoma

Introduction: Vascular endothelial growth factor (VEGF) is critical to tumor angiogenesis, tumor growth and metastasis. However, in neuroblastoma, bevacizumab, a humanized anti-VEGF antibody, has demonstrated limited efficacy alone or in combination with chemotherapy. The oncogene MDM2, a major negative regulator of p53, is also a regulator of hypoxia inducible factor-1α (HIF-1α), and inhibition of MDM2 has been shown in vitro to suppress HIF-1α as well as downstream VEGF expression. We have previously demonstrated that MDM2 inhibition with the small molecule inhibitor, Nutlin-3a, suppresses tumor angiogenesis and tumor growth in an in vivo, orthotopic model of neuroblastoma. Therefore we hypothesize that bevacizumab in combination with Nutlin-3a leads to cooperative inhibition of tumor angiogenesis, tumor growth, and metastasis in an in vivo model of neuroblastoma. Methods: Forty nude mice were intrarenally implanted with the human neuroblastoma cell line, SH-SY5Y. Two weeks after tumor implantation, mice were administered respective treatments for two weeks; control (Nutlin vehicle and bevacizumab vehicle), Nutlin-3a (200 mg/kg/dose BID x 14 days), bevacizumab (5mg/kg/dose BIW x 2 weeks), combination (Nutlin-3a and bevacizumab as above). After two weeks of treatment, all mice were sacrificed. At necropsy, tumors were resected, weighed and preserved. Livers from all mice were resected and preserved. Angiogenesis of preserved xenograft tumors was evaluated by immunohistochemistry for vascular markers, such as endothelial cells (CD-31), perivascular basement membrane (type-IV collagen), and vascular mural cells (αSMA). Tumors were also evaluated for apoptosis. All immunostained tumor tissue underwent digital quantification. Preserved liver tissue underwent H&E staining and histologic analysis for metastasis. Results: The combination of Nutlin-3a and bevacizumab more effectively inhibited xenograft tumor growth than either agent alone when compared to control treatment (79% suppression, p=0.01). Digital quantification of immunostained tumor tissue treated with combination therapy demonstrated significant inhibition of endothelial cells, perivascular basement membrane, and vascular mural cells compared to control treatment tumors (Figure 1). Nutlin-3a alone and in combination with bevacizumab led to significant tumor apoptosis and a significant decrease in both the incidence of metastasis and metastatic burden. Conclusions: We conclude that bevacizumab combined with Nutlin-3a cooperatively inhibits tumor growth, tumor angiogenesis, and metastasis in neuroblastoma. By targeting VEGF and p53 pathways, this novel anti-angiogenic regimen may provide more effective tumor suppression in patients with neuroblastoma and other p53 wild-type tumors.

Selective inhibition of VEGFR2 activity with a human anti-VEGF monoclonal antibody decreases tumor growth and macrophage infiltration in an orthotopic model of breast cancer.

Abstract Abstract #1034 In general tumor associated macrophages confer a negative prognosis in patients with breast cancer. This is due in part to the fact that macrophages can promote angiogenesis and mediate the angiogenic switch in tumors. Vascular endothelial growth factor (VEGF) is a primary stimulant of angiogenesis as well as a macrophage chemotactic protein. Inhibition of VEGF is an attractive therapeutic strategy that has shown to be beneficial in combination with chemotherapy for some breast cancer patients. However, the mechanism by which inhibition of VEGF affects tumor growth appears to involve more than its effect on endothelial cells. We have previously shown that 2C3 (PGN-310), a mouse monoclonal antibody that prevents VEGF from binding to VEGF receptor 2, decreases tumor growth, angiogenesis, and macrophage infiltration into pancreatic tumors. In this study, we test a fully human version of 2C3, termed r84 (PGN-311), for its effect on established orthotopic MDA-MB-231 breast tumors in SCID mice. Orthotopic tumors were established by injecting one million MDA-MB-231 cells into the mammary fat pad of SCID mice. Therapy with saline (n=5), bevacizumab (n=8), 2C3 (n=5), or r84 (n=9) at 250 μg/ip injection twice weekly was initiated on day 26 post tumor cell injection (mean initial tumor volume = 150 mm3) and continued for approximately 3 weeks. Upon sacrifice, tumor weight was determined and the tumor and other organs were snap frozen or fixed in formalin and paraffin-embedded for histology. Anti-VEGF therapy inhibited growth of orthotopic breast tumors (on day 48, Mean ± SEM: control, 822 ± 160; bevacizumab, 344 ± 29; 2C3, 309 ± 69; r84, 368 ± 38 mm3;all p &amp;lt; 0.001 vs control). Furthermore, immunohistochemical analysis of tumors from control and anti-VEGF treated animals demonstrated that each anti-VEGF therapy reduced microvessel density and macrophage infiltration. Additionally, we also determined that inhibition of VEGF activity with 2C3 reduces VEGF-induced migration of MDA-MB-231 cells in vitro in a transwell assay. In summary, we demonstrate that r84 a unique fully human anti-VEGF antibody is effective in reducing tumor microvessel density, macrophage infiltration into tumors, and the growth of breast tumors implanted into SCID mice. These data suggest that inhibition of VEGF receptor 2 activity with an anti-VEGF monoclonal antibody is sufficient for effective blockade of the pro-tumorigenic activities of VEGF. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1034.

Biological activity of bevacizumab, a humanized anti-VEGF antibody in vitro

Bevacizumab (Avastin, Genentech) is a humanized monoclonal antibody targeting vascular endothelial growth factor (VEGF), a critical angiogenic factor involved in both physiological and pathological conditions. It has been recently approved by the US FDA as a first-line therapy for widespread metastatic colorectal cancer. This report is a detailed biological characterization of bevacizumab in a variety of in vitro models. It is shown that bevacizumab potently neutralizes VEGF and blocks its signal transduction through both the VEGFR-1 and VEGFR-2 receptors, as demonstrated by the inhibition of VEGF-induced cell proliferation, survival, permeability, nitric oxide production, as well as migration and tissue factor production. Although bevacizumab retains the ability to bind to human Fcgamma receptors and complement protein C1q, it does not demonstrate cell or complement-mediated cytotoxicity in either VEGF producing or targeting cells. Thus the mechanism of anti-tumor activity of bevacizumab is most likely due to its anti-angiogenesis effect through binding and neutralization of secreted VEGF.

Phase I safety, pharmacokinetic and pharmacodynamic study of recombinant human anti-VEGF antibody HuMV833 in patients with advanced cancer

Phase I safety, pharmacokinetic and pharmacodynamic study of recombinant human anti-VEGF antibody HuMV833 in patients with advanced cancer