Potent neutralization of VEGF biological activities with a fully human antibody Fab fragment directed against VEGF receptor 2

Using capillary electrophoresis sodium dodecyl sulfate (CE-SDS) and liquid chromatograph mass spectrometry (LC-MS) to identify glycosylated heavy chain heterogeneity in the anti-VEGFR-2 monoclonal antibody

The size variant, which can be measured by capillary electrophoresis sodium dodecyl sulfate (CE-SDS), is a critical quality attribute of monoclonal antibodies (mAbs). The CE-SDS size heterogeneity can hardly be identified by tandem mass spectrometry, which is an intractable obstacle of mAb development and quality control across the industry. We analyzed the purity of an anti-vascular endothelial growth factor receptor 2 (VEGFR-2) mAb, an antagonist of the human VEGFR-2, through reduced CE-SDS and observed glycosylated heavy chain heterogeneity. The heterogeneity has potential impact on safety, efficacy, and stability of drugs for clinical use. Therefore, it should be characterized so as to evaluate its potential risk. In order to identify the heterogeneity, we used mass spectrometry to confirm that the molecular size heterogeneity was not due to peptide bond cleavage in the heavy chain. Subsequently, we employed mass-spectrometry-glycosylation profiling and CE-SDS analysis of various glycosidase-treated samples, in addition to the preparation of mAb references with different glycoforms. Ultimately, we demonstrated that the heavy chain heterogeneity was induced by different levels of galactosylation modifications which will potentially impact the efficacy of antibody drugs (i.e., complement-dependent cytotoxicity). In this study, potential risk caused by heavy chain size heterogeneity was evaluated, which addressed the obstacle of mAb development and quality control. Therefore, this study offers a feasible approach for the investigation and identification of heavy chain heterogeneity in reduced CE-SDS, providing a novel strategy for mAb quality control and evaluation.

How May Ramucirumab Help Improve Treatment Outcome for Patients with Gastrointestinal Cancers?

GI cancers are characterized by high recurrence rates and a dismal prognosis and there is an urgent need for new therapeutic approaches. This is a narrative review designed to provide a summary of the efficacy as measured by overall survival, progression free survival, and safety data from phase 3 randomized controlled GI clinical trials of ramucirumab including those from important pre-specified patient subgroups and evidence from real clinical practice worldwide. Quality of life (QOL) is discussed where data are available. Our aim was to summarize the efficacy and safety of ramucirumab in the treatment of GI cancers using these existing published data with a view to demonstrating how ramucirumab may help improve treatment outcome for patients with GI cancers. The data indicate that ramucirumab is efficacious, safe, and tolerable across the intent-to-treat patient populations as a whole and across several pre-specified subgroups, even those whose disease is traditionally more difficult to treat. Furthermore, survival outcomes observed in real-world clinical practice demonstrate similar data from phase 3 clinical trials even in patients with complications, suggesting that the benefits of ramucirumab translate in actual clinical practice.

Preclinical evaluation of anti-VEGFR2 monoclonal antibody ramucirumab labelled with zirconium-89 for tumour imaging

The key factors participating in angiogenesis include vascular endothelial growth factor (VEGF) and its receptors (VEGFRs), particularly VEGFR2. Angiogenesis suppression comprises the blocking of the VEGFR2 binding site by the monoclonal antibody ramucirumab (RAM). Our study focused on RAM radiolabelling with zirconium-89 along with subsequent in vitro and in vivo biological evaluation. RAM was conjugated with the bifunctional chelator p-SCN-Bn-deferoxamine (DFO) and subsequently radiolabelled with [89 Zr]Zr-oxalate. The binding affinity of [89 Zr]Zr-DFO-RAM to VEGFR2 was tested in vitro on prostate (PC-3) and ovary adenocarcinoma (SK-OV-3) cell lines. The positron emission tomography/computed tomography (PET/CT) imaging and ex vivo biodistribution experiments were performed in PC-3 and SK-OV-3 xenografted mice. The in vitro experiments revealed the preserved binding affinity of [89 Zr]Zr-DFO-RAM to VEGFR2. The obtained ex vivo biodistribution data showed the uptake in PC-3 and SK-OV-3 tumours at about 8.7 ± 0.2 and 12.1 ± 1.6%ID/g, respectively. The tumour-to-muscle ratio for 1, 3 and 6 days post injection was 3.9, 5.5 and 5.12 for PC-3 and 6.0, 8.0 and 8.82 for SK-OV-3 tumours, respectively. PET/CT images showed high radioactivity accumulation in the tumours starting already on the first day after tracer administration. The obtained results proved the potency of [89 Zr]Zr-DFO-RAM to target and image VEGFR2-positive tumours in vivo.

Advances in pharmacotherapeutics for hepatocellular carcinoma

INTRODUCTION

Although hepatocellular carcinoma (HCC) is the most frequent primary liver cancer, there are limited therapeutic options for the advanced stages. Sorafenib was the first tyrosine-kinase inhibitor (TKI) approved for unresectable HCC and remained the only effective choice for a decade. The horizon of systemic treatments drastically expanded in the latest years, opening new interesting possibilities.

AREAS COVERED

In this manuscript, the authors have analysed the recent advances in pharmacotherapy for HCC, discussing their mechanisms of action, the clinical efficacy and the safety profile of currently available first, second-and third-line treatments. The authors have also analysed the role of immune system modulators, in particular immune checkpoints inhibitors (ICIs), based on the limited data published so far.

EXPERT OPINION

The emergence of new targeted therapies, such as lenvatinib, have changed the landscape of HCC therapy. Tumor extension, differences in objective response rates and adverse events profiles should be considered to tailor the choice of the first-line agent. Sorafenib remains the most studied drug, with much real-world data available. The efficacy of second line therapies has only been proven in non-responder or sorafenib-intolerant patients. Unfortunately, studies directly comparing the second-line agents regorafenib, ramucirumab and cabozantinib are still lacking.

Human plasminogen-derived N-acetyl-Arg-Leu-Tyr-Glu antagonizes VEGFR-2 to prevent blood-retinal barrier breakdown in diabetic mice

Targeting the vascular endothelial growth factor (VEGF)/its receptor-2 (VEGFR-2) system has become a mainstay of treatment for many human diseases, including retinal diseases. We examined the therapeutic effect of recently developed N-acetylated Arg-Leu-Tyr-Glu (Ac-RLYE), a human plasminogen kringle-5 domain-derived VEGFR-2 antagonists, on the pathogenesis of diabetic retinopathy. Ac-RLYE inhibited VEGF-A-mediated VEGFR-2 activation and endothelial nitric oxide synthase (eNOS)-derived NO production in the retinas of diabetic mice. In addition, Ac-RLYE prevented the disruption of adherens and tight junctions and vascular leakage by inhibiting S-nitrosylation of β-catenin and tyrosine nitration of p190RhoGAP in the retinal vasculature of diabetic mice. Peptide treatment preserved the pericyte coverage of retinal capillaries by upregulating angiopoietin-2. These results suggest that Ac-RLYE potentially prevents blood-retinal barrier breakdown and vascular leakage by antagonizing VEGFR-2; Ac-RLYE can be used as a potential therapeutic drug for the treatment of diabetic retinopathy.

Recent developments in antibody derivatives against colorectal cancer; A review

Colorectal cancer (CRC) is the fourth most common cause of cancer and mortality worldwide and is the third most common cancer in men and women. Surgery, radiotherapy, and chemotherapy are conventionally used for the treatment of colorectal cancer. However, these methods are associated with various side effects on normal cells. Thus, new studies are moving towards more effective and non-invasive methods for treatment of colorectal cancer. Targeted therapy of CRC is a promising new approach to enhance the efficiency and decrease the toxicity of the treatment. In targeted therapy of CRC, antibody fragments can directly inhibit tumor cell growth and proliferation. They also can act as an ideal carrier for targeted delivery of anticancer drugs. In the present study, the structure and function of different formats of antibody fragments, immune-targeted therapy of CRC using antibody fragments will be discussed.

Multimodal Imaging to Detect in vivo Responses to Aflibercept Therapy in a Mouse Model of Type 3 Neovascularization

PURPOSE

The aim of this study was to characterize the response to aflibercept in a mouse model of type 3 neovascularization, the neoretinal vascularization (NRV) 2 mouse line.

METHODS

Twelve NRV2 mice were assigned to one of the following groups: (1) 6 mice were injected with aflibercept 3 µg/g at postnatal day (P) 15 ("aflibercept" group), and (2) the remaining 6 mice did not receive any treatment ("placebo" group). The mice were examined at P30 and P44.

RESULTS

The NRV mice's retinas were characterized by regions of depigmentation that were topographically associated with hyperfluorescent lesions seen on fluorescein angiography (FA) images. On optical coherence tomography images, intraretinal neovascularizations were visualized as hyperreflective lesions mainly localized within the outer plexiform and outer nuclear layers. The average number of intraretinal neovascular lesions visualized on FA at P30 was 5.0 ± 2.2 in the aflibercept group and 20.7 ± 2.4 in the placebo group (p < 0.0001). At P44, the average number of intraretinal lesions was still lower in the aflibercept group, although this difference was not statistically significant (p = 0.088).

CONCLUSION

Aflibercept therapy was effective in inhibiting pathologic angiogenesis in the NRV2 mouse model. However, the successive treatment washout resulted in an increase in the number of lesions.

Ramucirumab, A Second-Line Option For Patients With Hepatocellular Carcinoma: A Review Of The Evidence

Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer and predominantly develops in patients with liver cirrhosis. In patients with advanced disease, such as extra-hepatic extension or portal vein involvement, and with intermediate disease unsuitable for locoregional therapies, systemic therapy is recommended, if liver function and performance status are adequate. Following a decade of negative Phase III trials since the approval of sorafenib, more recently several drugs have proven efficacy both in first line versus sorafenib (lenvatinib) or in second line versus placebo (regorafenib, cabozantinib, ramucirumab). In this review, we summarize the preclinical and clinical evidence supporting the use of ramucirumab, a recombinant IgG1 monoclonal antibody that specifically binds to Vascular Endothelial Growth Factor receptor 2 (VEGFR-2), in HCC. Following the results of the REACH trial, that was negative in the overall study population but identified a subgroup that could benefit from ramucirumab treatment, the REACH-2 trial was a randomized, placebo-controlled trial, designed to assess ramucirumab as second line in patients with alpha-fetoprotein (AFP) ≥400 ng/mL. The results of REACH-2 were published in February 2019, leading to Food and Drug Administration and European Medicines Agency approval of the drug as second-line agent for advanced HCC (after sorafenib) in patients with AFP ≥400 ng/mL. For the first time in the history of systemic treatments for HCC, a predictive factor of efficacy was identified. In this review, we also discuss the potential clinical development of systemic treatments in HCC, focusing on combination therapies with immunotherapy (following the recent results of the combination of atezolizumab and bevacizumab in the IMbrave 150 clinical trial) and treatment sequences as a way to maximize survival benefit.

Ramucirumab: A Review in Hepatocellular Carcinoma

Ramucirumab (Cyramza®), a fully human anti-VEGFR-2 monoclonal antibody, has been approved as monotherapy for the treatment of patients with hepatocellular carcinoma (HCC) and α-fetoprotein levels ≥ 400 ng/mL who have been treated with sorafenib. Ramucirumab significantly prolonged overall survival (OS) and progression-free survival (PFS) relative to placebo in this population in the randomized, double-blind phase 3 REACH 2 trial. These benefits were seen in key prespecified subgroups based on demographic and disease characteristics. Ramucirumab had an acceptable tolerability profile and manageable safety profile in these patients, with the majority of treatment-related adverse events being mild or moderate in severity. The safety profile of ramucirumab was consistent with that expected for agents targeting the VEGF/VEGFR axis. Currently, ramucirumab is the only therapy specifically tested in patients with α-fetoprotein levels ≥ 400 ng/mL, which is associated with an aggressive disease and poor prognosis. Therefore, ramucirumab is an important treatment option for patients with HCC and α-fetoprotein levels ≥ 400 ng/mL who have been treated with sorafenib.

From Biology to Therapy: Improvements of Therapeutic Options in Lung Cancer

Lung cancer is the leading cause of cancer-related mortality around the world, despite effective chemotherapeutic agents, the prognosis has remained poor for a long time. The discovery of molecular changes that drive lung cancer has led to a dramatic shift in the therapeutic landscape of this disease. In "in vitro" and "in vivo" models of NSCLC (Non-Small Cell Lung Cancer), angiogenesis blockade has demonstrated an excellent anti-tumor activity, thus, a number of anti-angiogenic drugs have been approved by regulatory authorities for use in clinical practice. Much more interesting is the discovery of EGFR (Epithelial Growth Factor Receptor) mutations that predict sensitivity to the anti-EGFR Tyrosine Kinase Inhibitors (TKIs), a class of drugs that has shown to significantly improve survival when compared with standard chemotherapy in the first-line treatment of metastatic NSCLC. Nevertheless, after an initial response, resistance often occurs and prognosis becomes dismal. Biomolecular studies on cell line models have led to the discovery of mutations (e.g., T790M) that confer resistance to anti-EGFR inhibitors. Fortunately, drugs that are able to circumvent this mechanism of resistance have been developed and have been recently approved for clinical use. The discovery of robust intratumor lymphocyte infiltration in NSCLC has paved the way to several strategies able to restore the immune response. Thus, agents interfering with PD-1/PD-L1 (Programmed Death) pathways make up a significant portion of the armamentarium of cancer therapies for NSCLC. In all the above-mentioned situations, the basis of the success in treating NSCLC has started from understanding of the mutational landscape of the tumor.

Phage display antibody libraries: A robust approach for generation of recombinant human monoclonal antibodies

Monoclonal antibodies (mAbs) and their derivatives have achieved remarkable success as medicine, targeting both diagnostic and therapeutic applications associated with communicable and non-communicable diseases. In the last 3 to 4 decades, tremendous success has been manifested in the field of cancer therapy, autoimmune diseases, cardiovascular and infectious diseases. MAbs are the fastest growing class of biopharmaceuticals, with more than 25 derivatives are in clinical use and 7 of these have been isolated through phage display technology. Phage display technology has gained impetus in the field of medical and health sciences, as a large repertoire of diverse recombinant antibodies, targeting various antigens have been generated in a short span of time. A prominent number of phage display derived antibodies are already approved for therapy and significant numbers are currently in clinical trials. In this review we have discussed the various strategies employed for generation of monoclonal antibodies; their advantages, limitations and potential therapeutic applications. We also discuss the potential of phage display antibody libraries in isolation of monoclonal antibodies.

Ramucirumab and its use in the treatment of hepatocellular carcinoma

Ramucirumab is a fully humanized monoclonal antibody directed selectively at VEGFR-2 - a key player in the VEGF orchestra and angiogenic process. It has demonstrated clinical efficacy and a favorable safety profile in the treatment of a number of malignancies including gastric, lung, urothelial, colorectal and, most recently, advanced liver cancer. This article describes the recent Phase III trial results of ramucirumab in patients with hepatocellular carcinoma, including safety data and patient-reported outcomes, with particular emphasis on efficacy data in the patient population with baseline α-fetoprotein levels ≥400 ng/ml, traditionally considered a poor prognostic group.

Intraocular Penetration of a vNAR: In Vivo and In Vitro VEGF165 Neutralization

Variable new antigen receptor domain (vNAR) antibodies are novel, naturally occurring antibodies that can be isolated from naïve, immune or synthetic shark libraries. These molecules are very interesting to the biotechnology and pharmaceutical industries because of their unique characteristics related to size and tissue penetrability. There have been some approved anti-angiogenic therapies for ophthalmic conditions, not related to vNAR. This includes biologics and chimeric proteins that neutralize vascular endothelial growth factor (VEGF)₁₆₅, which are injected intravitreal, causing discomfort and increasing the possibility of infection. In this paper, we present a vNAR antibody against human recombinant VEGF₁₆₅ (rhVEGF₁₆₅) that was isolated from an immunized Heterodontus francisci shark. A vNAR called V13, neutralizes VEGF₁₆₅ cytokine starting at 75 μg/mL in an in vitro assay based on co-culture of normal human dermal fibroblasts (NHDFs) and green fluorescence protein (GFP)-labeled human umbilical vein endothelial cells (HUVECs) cells. In the oxygen-induced retinopathy model in C57BL/6:Hsd mice, we demonstrate an endothelial cell count decrease. Further, we demonstrate the intraocular penetration after topical administration of 0.1 μg/mL of vNAR V13 by its detection in aqueous humor in New Zealand rabbits with healthy eyes after 3 h of application. These findings demonstrate the potential of topical application of vNAR V13 as a possible new drug candidate for vascular eye diseases.

Isoprenaline/β2-AR activates Plexin-A1/VEGFR2 signals via VEGF secretion in gastric cancer cells to promote tumor angiogenesis

Background

The role of stress signals in regulating gastric cancer initiation and progression is not quite clear. It is known that stress signals modulate multiple processes such as immune function, cell migration and angiogenesis. However, few studies have investigated the mechanisms of how stress signals contribute to gastric cancer angiogenesis.

Methods

Here, we used β2-adrenergic receptor (β2-AR) agonist isoprenaline to imitate a stress signal and demonstrated the molecular mechanism underlying stress’s influence on tumor angiogenesis.

Results

We found that isoprenaline stimulated vascular endothelial growth factor (VEGF) secretion in gastric cancer cells and plexin-A1 expression was induced by human recombinant VEGF165 in both gastric cancer cells and vascular endothelial cells. Furthermore, interfere with plexin-A1 expression in gastric cancer cells influence HUVEC tube formation, migration and tumor growth in vivo.

Conclusions

These findings suggest that isoprenaline stimulate VGEF secretion and subsequently up-regulate the expression of plexin-A1 and VEGFR2 in gastric cancer cells, which form a positive impetus to promote tumor angiogenesis. This study reveals a novel molecular mechanism that a stress signal like isoprenaline may enhance angiogenesis via activating plexin-A1/VEGFR2 signaling pathway in gastric cancer, which may be a potential target in development of an anti-angiogenic therapy for gastric cancer.

Evolution of ramucirumab in the treatment of cancer - A review of literature

Ramucirumab is a recombinant human monoclonal antibody and is used in the treatment of advanced malignancies. Its mechanism of action is by inhibiting angiogenesis in tumor cells by targeting the vascular endothelial growth factor receptor 2. United States Food and Drug Administration (FDA) approved it initially in 2014 for the treatment of advanced gastric or gastro-esophageal junction adenocarcinoma and metastatic non-small cell lung carcinoma. It was approved by FDA in 2015 for the treatment of advanced colorectal cancer. This manuscript consolidates pre-clinical trials to phase I, II, and III trial data indicating the effects of ramucirumab on different cancer types, which led to its approval. By comparing these clinical trials alongside each other, we can more easily examine the studies that have already been completed, along with currently ongoing studies and potential further areas of interest for this newly approved treatment. This approach makes it convenient to compare dosages, overall survival, adverse events, as well as possible routes for combination therapy with ramucirumab. By compiling results for various oncological malignancies, we can differentiate between treatments that are effective and have the highest incidence of stable disease, and those that do not seem promising. Ramucirumab has been effective in the treatment of various carcinomas and this article outlines other tumors in which this treatment option may be successful.

Arg-Leu-Tyr-Glu tetrapeptide inhibits tumor progression by suppressing angiogenesis and vascular permeability via VEGF receptor-2 antagonism

The tetrapeptide Arg-Leu-Tyr-Glu (RLYE) is known to inhibit vascular endothelial growth factor-A (VEGF-A)-induced angiogenesis in vitro. Herein, we examined its underlying mechanism and antitumor activity associated with vascular remodeling. RLYE inhibited VEGF-A-induced angiogenesis in a mouse model and suppressed VEGF-A-induced angiogenic signal cascades in human endothelial cells. However, RLYE showed no inhibitory effect on VEGF-A-induced proliferation and migration of multiple myeloma cells expressing VEGF receptor (VEGFR)-1, but not VEGFR-2. In addition, RLYE showed no inhibitory effect on angiogenic activities induced by VEGF-B, basic fibroblast growth factor, epithermal growth factor, sphingosine-1-phosphate, and placental growth factor. RLYE bound specifically to VEGFR-2 at the VEGF-A binding site, thereby blocking VEGF-A-VEGFR-2 binding and VEGF-A-induced VEGFR-2 internalization. The RLYE peptide inhibited tumor growth and metastasis via suppression of tumor angiogenesis in tumor-bearing mice. Moreover, RLYE showed a synergistic effect of the cytotoxic agent irinotecan on tumor cell apoptosis and tumor progression via tumor vessel normalization due to stabilization of VE-cadherin-mediated adherens junction, improvement of pericyte coverage, and inhibition of vascular leakage in tumors. Our results suggest that RLYE can be used as an antiangiogenic and tumor blood vessel remodeling agent for inhibition of tumor growth and metastasis by antagonizing VEGFR-2, with the synergistic anti-cancer effect via enhancement of drug delivery and therapeutic efficacy.

Current status of ramucirumab in gastroesophageal adenocarcinoma

Outcomes of patients with advanced gastric or gastroesophageal junction adenocarcinoma (GEAC) remain poor despite recent advances. The standard of care in the management of this disease had not changed much over the past decade. In the first line, a platinum containing doublet/triplet is used, while in <20% of patients with human epithelial growth factor receptor type 2 overexpressing GEACs, trasuzumab can provide a modest advantage. Until recently, no standard second-line regimens existed; however, the results of the REGARD and RAINBOW trials led to the approval of ramucirumab in the second-line setting. From these trials it is clear that paclitaxel and ramucirumab should be used if possible. The placement of ramucirumab may become less clear as the data from immune oncology trials in GEAC emerge.

Spotlight on ramucirumab in the treatment of nonsmall cell lung cancer: design, development, and clinical activity

The vascular endothelial growth factor (VEGF) and receptor is a therapeutic target because of the importance of this pathway in carcinogenesis. This pathway regulates and promotes angiogenesis as well as increases endothelial cell proliferation, permeability, and cancer survival. Ramucirumab is a new fully human monoclonal antibody that targets the VEGF receptor-2, an important key receptor implicated in angiogenesis. Ramucirumab has been approved for the treatment of second-line advanced or metastatic non-small cell lung cancer (NSCLC) in combination with the chemotherapy agent docetaxel. This was based on the result of the randomized trial REVEL of 1,253 patients with metastatic NSCLC previously treated with a platinum-based combination therapy. The authors observed a significant improvement in overall survival (OS) with an acceptable toxicities profile. In this study, patients were randomized to receive ramucirumab plus docetaxel or placebo with docetaxel. The combination of docetaxel and ramucirumab showed an improved OS (hazard ratio [HR]: 0.86; 95% CI: 0.75, 0.98). Median OS was 10.5 months in the ramucirumab arm versus 9.1 months in the placebo arm. Regarding side effects, the toxicity described on the ramucirumab arm were principally diarrhea, fatigue, and neutropenia. The most common (5%) adverse reactions of grade 3 and 4 in the ramucirumab arm were fatigue, neutropenia, febrile neutropenia, leukopenia, and hypertension. Adding ramucirumab to docetaxel improves QoL of patients, and does not impair symptoms or functioning. There are currently several trials in progress evaluating the effects of ramucirumab in combination with other drugs in patients with advanced NSCLC.

Antiangiogenesis for Advanced Non-Small-Cell Lung Cancer in the Era of Immunotherapy and Personalized Medicine

Over the past decade, patients with advanced non-small-cell lung cancer (NSCLC) have witnessed substantial advances in regards to therapeutic alternatives. Among newly developed agents, angiogenesis inhibitors were extensively tested in different settings and have produced some favorable outcomes despite several shortcomings. Bevacizumab is the most examined agent in this context and has demonstrated significant survival benefits when combined with standard chemotherapy in eligible patients. Preliminary results on the addition of bevacizumab to erlotinib in patients with EGFR-mutated NSCLC seem promising. Other antiangiogenic agents were also tested, but ramucirumab and nintedanib are the only agents with a positive impact on survival. More recently, immune checkpoint inhibitors (ICIs) have had considerable success due to their prolonged durations of response, yet response rates are still deemed suboptimal, and various combination therapies are being tested in an effort to improve efficacy. Preclinical evidence suggests an immunosuppressive effect of pro-angiogenic factors, which sets up a plausible rationale for combining ICIs and antiangiogenic agents. Herein, we review the landmark data supporting the success of angiogenesis inhibitors, and we discuss the potential for combination with immunotherapy and targeted agents.

State of the art in anti-cancer mAbs

Following Milstein’s discovery, the monoclonal antibodies (mAbs) became a basic tool for biomedical science. In cancer field, since the first mAb was approved by the FDA a great improvement took place making of them a therapeutic option for many cancer types in the current clinical practice. Today, mAbs are being developed to target different molecules with different mechanisms of action and its target potential is unlimited. However, this huge and fast growing new field needs to be organized to better understand the treatment options we have to confront different cancer diseases. Current cancer targeted immunotherapies aim to achieve different goals like the regulation of osteoclast function, the delivery of cytotoxic drugs into tumor cells and the blockade of oncogenic pathways, neo-angiogenesis and immune checkpoints. Here, we reviewed the most relevant therapeutic mAbs for solid tumors available in current clinical practice.

Targeting fibroblast growth factor receptors and immune checkpoint inhibitors for the treatment of advanced bladder cancer: New direction and New Hope

Bladder cancer is one of the leading causes of death in Europe and the United States. About 25% of patients with bladder cancer have advanced disease (muscle-invasive or metastatic disease) at presentation and are candidates for systemic chemotherapy. In the setting of metastatic disease, use of cisplatin-based regimens improves survival. However, despite initial high response rates, the responses are typically not durable leading to recurrence and death in the vast majority of these patients with median overall survival of 15months and a 5-year survival rate of ⩽10%. Furthermore, unfit patients for cisplatin have no standard of care for first line therapy in advance disease Most second-line chemotherapeutic agents tested have been disappointing. Newer targeted drugs and immunotherapies are being studied in the metastatic setting, their usefulness in the neoadjuvant and adjuvant settings is also an intriguing area of ongoing research. Thus, new treatment strategies are clearly needed. The comprehensive evaluation of multiple molecular pathways characterized by The Cancer Genome Atlas project has shed light on potential therapeutic targets for bladder urothelial carcinomas. We have focused especially on emerging therapies in locally advanced and metastatic urothelial carcinoma with an emphasis on immune checkpoints inhibitors and FGFR targeted therapies, which have shown great promise in early clinical studies.

Ramucirumab Clinical Development: an Emerging Role in Gastrointestinal Tumors

Ramucirumab (IMC-1121B, LY3009806) is a fully human G1 monoclonal antibody that specifically targets vascular endotelial growth factor receptor 2 (VEGFR-2) with a substantially greater binding affinity than that of its natural ligands. Early clinical trials in patients with advanced solid tumors demonstrated that biologically relevant blood target concentrations are achievable with tolerable doses, and also showed some preliminary evidence of clinical activity. Several pivotal phase III trials have now been concluded and have led regulatory agencies to grant marketing authorization to ramucirumab for use as second line therapy in patients with advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma (as single agent or in combination with paclitaxel), in patients with advanced colorectal carcinoma (CRC) (in combination with infusional fluorouracil and irinotecan (FOLFIRI regimen)) and in patients with advanced non-small cell lung cancer (NSCLC) (in combination with docetaxel). In contrast, ramucirumab failed to significantly improve survival versus placebo as second line therapy in patients with advanced hepatocellular carcinoma (HCC). The aim of this review is to summarize the clinical development and emerging role of ramucirumab in gastrointestinal (GI) tumors, including relevant aspects of its mechanism of action, pharmacology, safety profile, and antitumor activity in gastric, HCC, and CRC carcinomas.

Antagonist antibodies to vascular endothelial growth factor receptor 2 (VEGFR-2) as anti-angiogenic agents

Interaction of numerous signaling pathways in endothelial and mesangial cells results in exquisite control of the process of physiological angiogenesis, with a central role played by vascular endothelial growth factor receptor 2 (VEGFR-2) and its cognate ligands. However, deregulated angiogenesis participates in numerous pathological processes. Excessive activation of VEGFR-2 has been found to mediate tissue-damaging vascular changes as well as the induction of blood vessel expansion to support the growth of solid tumors. Consequently, therapeutic intervention aimed at inhibiting the VEGFR-2 pathway has become a mainstay of treatment in cancer and retinal diseases. In this review, we introduce the concepts of physiological and pathological angiogenesis, the crucial role played by the VEGFR-2 pathway in these processes, and the various inhibitors of its activity that have entered the clinical practice. We primarily focus on the development of ramucirumab, the antagonist monoclonal antibody (mAb) that inhibits VEGFR-2 and has recently been approved for use in patients with gastric, colorectal, and lung cancers. We examine in-depth the pre-clinical studies using DC101, the mAb to mouse VEGFR-2, which provided a conceptual foundation for the role of VEGFR-2 in physiological and pathological angiogenesis. Finally, we discuss further clinical development of ramucirumab and the future of targeting the VEGF pathway for the treatment of cancer.

Phage display-derived human antibodies in clinical development and therapy

Over the last 3 decades, monoclonal antibodies have become the most important class of therapeutic biologicals on the market. Development of therapeutic antibodies was accelerated by recombinant DNA technologies, which allowed the humanization of murine monoclonal antibodies to make them more similar to those of the human body and suitable for a broad range of chronic diseases like cancer and autoimmune diseases. In the early 1990s in vitro antibody selection technologies were developed that enabled the discovery of “fully” human antibodies with potentially superior clinical efficacy and lowest immunogenicity.

Antibody phage display is the first and most widely used of the in vitro selection technologies. It has proven to be a robust, versatile platform technology for the discovery of human antibodies and a powerful engineering tool to improve antibody properties. As of the beginning of 2016, 6 human antibodies discovered or further developed by phage display were approved for therapy. In 2002, adalimumab (Humira®) became the first phage display-derived antibody granted a marketing approval. Humira® was also the first approved human antibody, and it is currently the best-selling antibody drug on the market. Numerous phage display-derived antibodies are currently under advanced clinical investigation, and, despite the availability of other technologies such as human antibody-producing transgenic mice, phage display has not lost its importance for the discovery and engineering of therapeutic antibodies.

Here, we provide a comprehensive overview about phage display-derived antibodies that are approved for therapy or in clinical development. A selection of these antibodies is described in more detail to demonstrate different aspects of the phage display technology and its development over the last 25 years.

Ramucirumab for the treatment of gastric cancers, colorectal adenocarcinomas, and other gastrointestinal malignancies

INTRODUCTION

The use of antiangiogenic strategy in the treatment of advanced colorectal cancers has been largely evidence-based. More recently, novel vascular endothelial growth factor receptor (VEGFR) inhibitors have been studied in other gastrointestinal diseases. Ramucirumab, a recombinant monoclonal antibody that binds to VEGFR2 extracellular domain with a much greater affinity compared to its natural ligand, showed second-line effectiveness for patients with gastric or colorectal carcinomas.

AREAS COVERED

We perform a narrative literature review. The aims of our work are to recall the current evidence of its efficacy in the treatment of gastric, hepatocellular and colorectal cancers and to present the ongoing studies enrolling gastrointestinal cancer patients in which ramucirumab is being tested. Expert commentary: The landscape of angiogenesis-inhibition for the treatment of GI malignancies is rapidly evolving. The results of the REGARD and RAINBOW trials renewed the interest for antiangiogenic agents in gastric cancer and determined a swift change in the treating paradigm for this disease. Accordingly, ramucirumab was shown to be effective in pretreated colorectal cancer patients and it is being tested in other gastrointestinal malignancies.

The safety and efficacy of ramucirumab for the treatment of metastatic colorectal cancer

INTRODUCTION

Ramucirumab (IMC-1121B, LY3009806) is a fully humanized monoclonal antibody that targets the extracellular domain of vascular endothelial growth factor receptor 2 (VEGFR2), the principal mediator of VEGF-A downstream effects in cancer angiogenesis. Ramucirumab has been recently approved for use in combination with FOLFIRI for the treatment of patients with metastatic colorectal cancer (mCRC) whose disease has progressed on a first line bevacizumab-, oxaliplatin- and fluoropyrimidine-containing regimen. This approval was based on the results of the RAISE phase III placebo-controlled trial. This study demonstrated that the addition of ramucirumab to irinotecan-based chemotherapy significantly improved progression-free and overall survival of patients with mCRC, with manageable toxicity.

AREAS COVERED

The aim of this drug profile is to briefly summarize the pharmacology, clinical efficacy, safety and tolerability of ramucirumab in the context of metastatic colorectal cancer, and to provide some perspective regarding the role of the drug in clinical practice. Expert commentary: Pending issues that shall be addressed in the upcoming years include the optimization of ramucirumab dosing schedule, assessment of its role with other chemotherapy regimens or in other treatment settings, comparative evaluation of this agent with other antiangiogenics, and identification of predictive biomarkers to improve the therapeutic index and cost-effectiveness of this drug.

Profile of ramucirumab in the treatment of metastatic non-small-cell lung cancer

The interaction between vascular endothelial growth factor and its receptor is an important therapeutic target due to the importance of this pathway in carcinogenesis. In particular, this pathway promotes and regulates angiogenesis as well as increases endothelial cell proliferation, permeability, and survival. Ramucirumab is a fully human monoclonal antibody that specifically targets the vascular endothelial growth factor receptor-2, the key receptor implicated in angiogenesis. Currently, ramucirumab is approved for the second-line treatment of metastatic non-small-cell lung cancer (NSCLC) in combination with docetaxel. In a Phase III clinical trial, ramucirumab was shown to improve the overall survival in patients with disease progression, despite platinum-based chemotherapy for advanced NSCLC. This review describes the pharmacology, pharmacokinetics and dynamics, adverse event profile, and the clinical activity of ramucirumab observed in Phase II and III trials in NSCLC.

Clinical pharmacokinetics and pharmacodynamics of ramucirumab in the treatment of colorectal cancer

INTRODUCTION

Colorectal cancer is the third most common cancer worldwide. The prognosis of colorectal cancer patients still remains dismal and half of them will develop metastatic disease. Angiogenesis plays an essential role in colorectal tumorigenesis, and the VEGF pathway is one of the targets that has been validated up to now. The use of antiangiogenics along with chemotherapy has become an accepted standard for colorectal cancer.

AREAS COVERED

This review discusses the efficacy and safety profile of ramucirumab, a fully human immunoglobulin G1 monoclonal antibody against the vascular endothelial growth factor receptor-2 (VEGFR-2), for the treatment of second-line metastatic colorectal cancer upon progression to first-line chemotherapy including anti-angiogenics.

EXPERT OPINION

Ramucirumab in combination with chemotherapy represents a valid option in second-line treatment of advanced colorectal cancer patients, who progressed on previous bevacizumab-based combinations. This agent demonstrates a similar benefit in terms of overall survival to other angiogenesis inhibitors (bevacizumab and ziv-aflibercept) used in this setting.

Prostaglandin E2 and vascular endothelial growth factor A mediate angiogenesis of human ovarian follicular endothelial cells

STUDY QUESTION

Which receptors for prostaglandin E2 (PGE2) and vascular endothelial growth factor A (VEGFA) mediate angiogenesis in the human follicle around the time of ovulation?

SUMMARY ANSWER

PGE2 and VEGFA act via multiple PGE2 receptors (PTGERs) and VEGF receptors (VEGFRs) to play complementary roles in follicular angiogenesis.

WHAT IS KNOWN ALREADY

Production of PGE2 and VEGFA by the follicle are prerequisites for ovulation. PGE2 is an emerging regulator of angiogenesis and has not been examined in the context of the human ovulatory follicle. VEGFA is an established regulator of follicular angiogenesis.

STUDY DESIGN, SIZE, DURATION

Ovarian biopsies containing the ovulatory follicle were obtained from 11 women of reproductive age (30-45 years) undergoing surgery for laparoscopic sterilization. In some cases, women received hCG to substitute for the ovulatory LH surge before ovarian biopsy. In addition, aspirates from four women of reproductive age (18-31 years) undergoing gonadotrophin stimulation for oocyte donation were obtained for isolation of human ovarian microvascular endothelial cells (hOMECs).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ovarian biopsies were utilized for immunocytochemical detection of von Willebrand factor to identify endothelial cells. hOMECs were cultured with PGE2, PTGER receptor selective agonists, VEGFA, or VEGFR selective agonists. hOMECs were assessed for proliferation by Ki67 immunocytochemistry. hOMEC migration was determined by counting cells which migrated through a porous membrane in vitro. Sprout formation was quantified by determining sprout number and length from photographs take after culture of hOMECs in a 3-dimensional matrix.

MAIN RESULTS AND THE ROLE OF CHANCE

Endothelial cells were not observed within the granulosa cell layer of human ovulatory follicles prior to an ovulatory dose of hCG and were first seen amongst granulosa cells 18-34 h after hCG. In vitro, PGE2 enhanced migration and sprout formation but did not alter hOMEC proliferation. Agonists selective for each PTGER increased migration with no change in proliferation. PTGER1 and PTGER2 agonists increased the number of sprouts, while only PTGER1 affected sprout length. VEGFA increased hOMEC proliferation, migration, and formation of structures resembling capillary sprouts. Signaling through VEGFR1 promoted hOMEC migration, proliferation, and the formation of few, long endothelial cell sprouts, while VEGFR2 stimulation promoted hOMEC migration and the formation of many, short sprouts. All effects of treatments in vitro were considered significant at P < 0.05.

LIMITATIONS, REASONS FOR CAUTION

While primary cultures of hOMECs respond to PGE2 and VEGFA differently than other cultured endothelial cells, hOMECs may not respond to PGE2 and VEGFA in vivo as they do in vitro.

WIDER IMPLICATIONS OF THE FINDINGS

Agonists and antagonists selective for PTGER1, PTGER2, VEGFR1, or VEGFR2 may have therapeutic value to promote or prevent ovulation in women.

STUDY FUNDING/COMPETING INTERESTS

This research was supported by grant funding from the Eunice Kennedy Shriver National Institutes of Child Health and Human Development (HD071875 to D.M.D., T.E.C., M.B.). The authors have no conflicts of interest to disclose.

Angiogenesis inhibitors in gastric and gastroesophageal junction cancer

Despite significant improvements in systemic chemotherapy during the past two decades, the prognosis of patients with advanced gastric and gastroesophageal junction adenocarcinoma remains poor. Because of molecular heterogeneity, it is essential to classify tumors based on the underlying oncogenic pathways and to develop targeted therapies acting on individual tumors. Unfortunately, although a number of molecular targets have been studied, very few of these agents can be used in a clinical setting. In this review, we summarize the available data on anti-angiogenic agents in advanced/metastatic gastric cancer.

The Impact of Ramucirumab on Survival in Patients with Advanced Solid Tumors: A Systematic Review and Meta-Analysis of Randomized II/III Controlled Trials

BACKGROUND AND OBJECTIVES

Ramucirumab is a fully immunoglobulin G (lgG) monoclonal antibody targeting vascular endothelial growth factor receptor type 2 (VEGFR2). Previous clinical trials suggested ramucirumab could improve the survival and increase the risk of adverse effects. Here, we aimed to assess the efficacy and safety of ramucirumab in the treatment of advanced solid tumors.

METHODS

Publications were searched from Pubmed, Embase database and clinicaltrials.gov. Hazard ratio (HR) and 95% confidence interval (95% CI) were calculated to evaluate efficacy, and the risk ratio (RR) for adverse effects.

RESULTS

Ten relevant studies were included. Ramucirumab resulted in significant benefit in overall survival [OS, HR and 95% CI 0.87 (0.82-0.93), I(2): 0.0%] and progression-free survival [PFS, HR and 95% CI 0.74 (0.66-0.82), I(2): 67.4%]. Also the difference of time to progression (TTP) and objective response rate (ORR) between two groups were also significant [0.70 (0.57-0.88) and 1.78 (1.40-2.25), respectively]. Ramucirumab could increase the risk of total adverse effects (TAEs, of any grade) by 1% (from 0 to 2%) and severe adverse effects (SAEs, grade > 2) by 17% (from 9 to 26%). The most frequently occurring TAEs were fatigue (54.71%), neutropenia (42.74%), bleeding (37.55%), nausea (34.63%) and stomatitis (33.74%). Most frequently occurring SAEs (grade ≥3) were neutropenia (33.43%), fatigue (12.08%), leukopenia (10.59%), hypertension (8.99%) and liver injury (8.74%).

CONCLUSION

Ramucirumab could improve OS and PFS for patients suffering from advanced solid tumors. Ramucirumab could increase the risk of TAEs and SAEs.

Monoclonal Antibodies Approved for Cancer Therapy

Twenty-four monoclonal antibodies (mAbs) targeted to a total of 16 different antigens are currently approved for the treatment of an increasing number of cancers. Six are directed against antigens expressed on B lymphocytes (ibritumomab tiuxetan, obinutuzumab, ofatumumab, and rituximab to CD20, brentuximab vedotin to CD30, and alemtuzumab to CD52); cetuximab, panitumumab, and necitumumab target EGFR; bevacizumab and ramucirumab are specific for VEGF and VEGFR2, respectively; pertuzumab, trastuzumab, and ado-trastuzumab target HER2; nivolumab and pembrolizumab are directed to the programmed cell death protein 1 (PD-1); and denosumab, ipilimumab, siltuximab, and dinutuximab recognize RANKL, CTLA-4, IL-6, and the disialoganglioside (GD2), respectively. In November 2015, the FDA approved daratumumab, the first anti-CD38 mAb and the first mAb to be approved for the treatment of multiple myeloma. Elotuzumab, targeted to the receptor SLAMF7, was also given approval for multiple myeloma soon after. Two antibodies are bispecific: the rat-mouse chimera, catumaxomab, recognizes both EpCAM and CD3, while blinatumomab, a bispecific T-cell-engaging (BiTE) fusion protein, targets both CD19 and CD3. Although mAbs used for cancer immunotherapy are generally better tolerated than small molecule chemotherapeutic drugs, their range of adverse effects is still wide and varied from mild gastrointestinal symptoms and transient rashes to severe cytopenias; anaphylaxis; autoimmunity; pulmonary, cardiac, hepatic, kidney, neurological, and embryofetal toxicities; and rare life-threatening toxidermias. Because of their immunogenic potential, mAbs generally carry warnings of immune reactions, especially anaphylaxis, but the observed incidences of such reactions are actually quite small. Cytopenias occur in some patients treated with mAbs during anticancer immunotherapy, but the underlying mechanisms frequently remain unexplored. Type II and III hypersensitivities induced by mAbs may be underdiagnosed. Severe infusion reactions have been reported for all the mAbs although some show a much higher incidence with the chimeric rituximab and humanized trastuzumab antibodies being the leading offenders. Distinguishing features in the literature between cytokine release syndrome and severe infusion reactions are often not clear. At least ten of the currently approved mAbs for cancer therapy show some pulmonary toxicity. These pulmonary adverse events can be grouped into four categories: interstitial pneumonitis and fibrosis, acute respiratory distress syndrome (ARDS), bronchiolitis obliterans organizing pneumonia (BOOP), and hypersensitivity pneumonitis. Cardiac adverse events, including congestive heart failure, decreased LVEF, myocardial infarction, cardiac arrest, and arrhythmias, have occurred with at least 11 of the mAbs. Papulopustular eruptions, cutaneous reactions that are not immune-mediated, as well as a range of other adverse mucocutaneous effects, are elicited in a large proportion of patients by mAbs targeted to EGFR. Other rare but mAb-induced serious adverse events are tumor lysis syndrome and progressive multifocal leukoencephalopathy.

Monoclonal antibodies-based treatment in gastric cancer: current status and future perspectives

Gastric cancer (GC) is the second leading cause of cancer-related death, and despite having improved treatment modalities over the last decade, for most patients, only modest improvements have been seen in overall survival. Recent progress in understanding the molecular biology of GC and the related signaling pathways offers, from the clinical point of view, promising advances for selected groups of patients. In the past, targeted therapies have significantly impacted the treatment strategy of several common solid tumors such as breast, colorectal, and lung cancers. Unfortunately, translational and clinical research shows fewer encouraging targeted treatments with regards to the GC. To date, only two monoclonal antibodies (mAb), named trastuzumab and ramucirumab, are approved for the treatment of advanced GC, suggesting that in GC, maybe more than in other cancers, effective targeted therapy requires patient selection based on precise predictive molecular biomarkers. The aim of this review is to summarize the available data on the clinical advantages offered by the use of mAbs in the treatment of advanced/metastatic GC. Future perspective is also discussed.

Ramucirumab for advanced gastric cancer or gastro-oesophageal junction adenocarcinoma

Ramucirumab, a fully humanized monoclonal antibody directed against vascular endothelial growth factor receptor 2, is the first targeted agent to have demonstrated an improvement in survival, as a single agent or in combination, in a molecularly unselected population in gastro-oesophageal cancer. Now that second-line treatment is routinely considered for patients with advanced gastro-oesophageal cancer, ramucirumab, with its favourable toxicity profile compared with cytotoxic treatment, provides a valuable additional treatment option.

Ramucirumab: A Review in Advanced Gastric Cancer

Ramucirumab (Cyramza(®)), an intravenously administered, monoclonal antibody against vascular endothelial growth factor receptor-2, is approved in the USA, EU and Japan (either as a single agent or in combination with paclitaxel) as second-line treatment in adults with advanced gastric or gastro-oesophageal junction adenocarcinoma. In two phase III trials (REGARD and RAINBOW) in this indication, overall survival and progression-free survival were significantly prolonged with ramucirumab 8 mg/kg every 2 weeks compared with placebo, and with ramucirumab 8 mg/kg every 2 weeks plus weekly paclitaxel compared with placebo plus paclitaxel. Ramucirumab had a generally acceptable tolerability profile in phase III trials; hypertension was the most common non-haematological adverse event of grade 3 or higher with ramucirumab (either alone or with paclitaxel). As the first antiangiogenic agent to provide significant survival benefit in patients with advanced gastric cancer, ramucirumab is a valuable option in the second-line treatment of advanced gastric or gastro-oesophageal junction adenocarcinoma.

Clinical utility of ramucirumab in advanced gastric cancer

Gastric cancer is currently the third most common cause of cancer deaths worldwide. Prognosis remains poor with most patients presenting with advanced or metastatic disease. A better understanding of angiogenesis has led to the investigation of drugs that inhibit the vascular endothelial growth factor (VEGF) pathway including anti-VEGF antibody therapy (eg, bevacizumab), inhibitors of angiogenic receptor tyrosine kinases (eg, sunitinib, sorafenib, apatinib, regorafenib), and inhibitors of vascular endothelial growth factor receptors (VEGFRs) (eg, ramucirumab). Ramucirumab, a VEGFR-2 inhibitor, is the first anti-angiogenic agent approved by the US Food and Drug Administration for use in the treatment of advanced gastric cancers. This review will focus on the clinical utility and potential use of ramucirumab in advanced gastric cancer.

Critical evaluation of ramucirumab in the treatment of advanced gastric and gastroesophageal cancers

Gastric (GC) and gastroesophageal junction (GEJ) cancers are two global health problems with a relatively high mortality, particularly in the advanced stage. Inhibition of angiogenesis is now contemplated as a classic treatment preference for myriad tumor types encompassing renal cell carcinoma, non-small cell lung cancer, colorectal cancer, glioblastoma, and ovarian cancer, among others. Bevacizumab and ramucirumab have been widely investigated in GC and GEJ cancer, with some controversy about their therapeutic role. Ramucirumab is a monoclonal antibody for vascular endothelial growth factor receptor-2, with demonstrated activity both as a monotherapy and as a part of combination strategy in the management of advanced GC/GEJ cancer. In this review article, we present a critical evaluation of the preclinical and clinical data underlying the use of this drug in this indication. Moreover, we provide a spotlight on the future perspectives in systemic therapy for advanced GC/GEJ cancer.

Phase I study of every 2- or 3-week dosing of ramucirumab, a human immunoglobulin G1 monoclonal antibody targeting the vascular endothelial growth factor receptor-2 in patients with advanced solid tumors

BACKGROUND

Ramucirumab is a fully human immunoglobulin G1 monoclonal antibody receptor antagonist designed to block the ligand-binding site of vascular endothelial growth factor receptor-2 (VEGFR-2). An initial phase I study evaluated ramucirumab administered weekly in advanced cancer patients. This phase I study of ramucirumab [administered every 2 or 3 weeks (Q2W or Q3W)] examined safety, maximum tolerated dose, pharmacokinetics, immunogenicity, antitumor activity, and pharmacodynamics.

PATIENTS AND METHODS

Patients with advanced solid malignancies were treated with escalating doses of ramucirumab i.v. over 1 h. Blood was sampled for pharmacokinetics studies throughout treatment; levels of circulating vascular endothelial growth factor-A (VEGF-A) and soluble VEGF receptors (R)-1 and -2 were assessed.

RESULTS

Twenty-five patients were treated with ramucirumab: 13 with 6, 8, or 10 mg/kg Q2W, and 12 with 15 or 20 mg/kg Q3W. The median treatment duration was 12 weeks (range 2-81). No dose-limiting toxicities were observed. The most frequently reported adverse events (AEs) included proteinuria and hypertension (n = 6 each), and diarrhea, fatigue and headache (n = 4 each). Treatment-related grade 3/4 AEs were: two grade 3 hypertension (10 and 20 mg/kg), one each grade 3 vomiting, fatigue (20 mg/kg), atrial flutter (15 mg/kg), and one each grade 4 duodenal ulcer hemorrhage (6 mg/kg) and grade 4 pneumothorax (20 mg/kg). Pharmacokinetic analysis revealed low clearance and half-life of ∼110-160 h. Analysis of serum biomarkers indicated considerable patient-to-patient variability, but trends toward elevated VEGF-A and a transient decline in soluble VEGFR-2. Fifteen patients (60%) had best response of stable disease, with a median duration of 13 months (range 2-18 months) in tumor types including colorectal, renal, liver, and neuroendocrine cancers.

CONCLUSION

Ramucirumab was well tolerated. Study results led to recommended phase II doses of 8 mg/kg Q2W and 10 mg/kg Q3W. Prolonged stable disease was observed, suggesting ramucirumab efficacy in various solid tumors.

CLINICALTRIALSGOV

NCT00786383.

Ramucirumab as second-line treatment for patients with metastatic esophagogastric adenocarcinoma

Ramucirumab is a fully humanized monoclonal antibody targeting the extracellular domain of the VEGF receptor 2. It prevents ligand binding to VEGF receptor 2 and receptor-mediated pathway activation in endothelial cells. After promising Phase I trial results in a variety of tumor types, two pivotal placebo-controlled Phase III trials conducted in patients with pretreated metastatic esophagogastric adenocarcinoma demonstrated significant clinical activity regarding the prolongation of overall survival both as monotherapy (REGARD study) and in combination with paclitaxel (RAINBOW study). Currently, ramucirumab is being investigated in the first-line treatment of esophagogastric adenocarcinoma in combination with capecitabine and cisplatin in a Phase III trial (RAINFALL).

Anti-angiogenic therapies for advanced esophago-gastric cancer

Neo-vascularization is a vital process for tumor growth and development which involves the interaction between tumor cells and stromal endothelial cells through several growth factors and membranous receptors which ultimately activate pro-angiogenic intracellular signaling pathways. Inhibition of angiogenesis has become a standard treatment option for several tumor types including colorectal cancer, glioblastoma and ovarian cancer. In gastric cancer, the therapeutic role of anti-angiogenic agents is more controversial. Bevacizumab and ramucirumab, two monoclonal antibodies, which target vascular endothelial growth factor-A and vascular endothelial growth factor receptor-2, respectively, have been demonstrated antitumor activity in patients with tumors of the stomach or esophagogastric junction. However, especially for bevacizumab, this antitumor activity has not consistently translated into a survival advantage over standard treatment in randomized trials. In this article, we provide an overview of the role of angiogenesis in gastric cancer and discuss the results of clinical trials that investigated safety and effectiveness of antiangiogenic therapies in this disease. A review of the literature has been done using PubMed, ClinicalTrials.gov website and the ASCO Annual Meeting Library.

Clinical advances in the development of novel VEGFR2 inhibitors

Angiogenesis inhibitors have produced significant advances in the treatment of several tumors including colorectal, lung, ovarian and renal carcinomas. These agents, however, modestly impact on the overall cure rate, and their activity is often limited because of the early outbreak of redundant pathways or resistance mechanisms. Moreover, no clear predictive factor has been identified for treatment selection in the clinic. Preclinical evidence suggest that antibodies targeting the vascular endothelial growth factor (VEGF) axis may exert their activity throughout the inhibition of VEGF receptor 2 (VEGFR2) phosphorylation, a key factor in the cancer angiogenic process. Among other molecules, ramucirumab, an intravenously administered, fully humanized monoclonal antibody (mAb) targeting the extracellular domain of the receptor, and apatinib, a potent oral inhibitor of the intracellular domain, are emerging as original antiangiogenic opportunities. This up-to-date review focuses on the development of VEGFR2 inhibitors across multiple cancers and presents results of the most recent researches, ranging from early phase I studies to randomized phase III trials, in which those drugs have been tested as a single-agent or in combination with different chemotherapy regimens.

Ramucirumab: preclinical research and clinical development

Ramucirumab (IMC-1121B, LY3009806), a fully humanized monoclonal antibody directed against the extracellular domain of vascular endothelial growth factor receptor 2 (VEGFR-2), is a new therapeutic option that selectively inhibits the human VEGFR-2 with a much greater affinity than its natural ligands. Based on the promising results of both preclinical and early clinical studies, ramucirumab has been tested in different tumor types either alone or in combination with chemotherapy. While it has recently been granted its first US Food and Drug Administration approval for use as a single agent in patients with advanced or metastatic gastric cancer or gastroesophageal junction carcinoma, its role for metastatic breast cancer or advanced non-small-cell lung cancer is still debated. The aims of this review are to recall and discuss the most significant preclinical and clinical studies that led to the development of ramucirumab and to present the results of the randomized clinical trials that have tested its efficacy in different malignancies, including gastric and lung cancer.

Generation and characterization of a novel human IgG1 antibody against vascular endothelial growth factor receptor 2

VEGF and its receptors, especially VEGFR2 (KDR), are known to play a critical role in angiogenesis under both physiological and pathological conditions, including cancer and angiogenic retinopathies. This study was aimed at developing a fully human IgG1 antibody (mAb-04) constructed from a phage-derived scFv, targeting the VEGF/VEGFR2 pathway. Firstly, an innovative transfection system, containing two recombinant expression vectors (pMH3 and pCApuro), were introduced into CHO-s cells and clones with higher yield selected accordingly. After an optimal fermentation condition was determined, fed-batch fermentation was performed in 5-L bioreactor with a final yield up to 60 mg/L. Further, cell proliferation, wound healing, transwell invasion, tube formation and chick embryo chorioallantoic membrane assays showed significant anti-angiogenic activity of mAb-04 in vitro and in vivo. In addition, the results of Western blotting indicated the ability of mAb-04 to inhibit VEGF-induced VEGFR2 signaling pathway. Finally, ADCC assay demonstrated that mAb-04 is capable of mediating tumor cell killing in presence of effector cells. This study has therefore proved that the full-length antibody targeting human VEGFR2 has potential clinical applications in the treatment of cancer and other diseases where pathological angiogenesis is involved.

Understanding the mechanisms of action of antiangiogenic agents in metastatic colorectal cancer: a clinician's perspective

Multiple clinical trials using bevacizumab, ziv-aflibercept, and regorafenib have recently demonstrated efficacy for patients with metastatic colorectal cancer. While the net clinical benefit of each of these therapies in the second-line and refractory disease setting appears to be similar, important distinctions exist between the agents at the pharmacodynamic, tumor microenvironment, and clinical levels. The purpose of this review is to survey the preclinical evidence regarding the mechanisms of action of these novel antiangiogenic agents and provide an overview of their respective clinical activity, while highlighting distinctions between therapies. Fundamental understanding of these distinctions may aid in clinical decisions and choice of antiangiogenic therapies.

Ramucirumab: targeting angiogenesis in the treatment of gastric cancer

Gastroesophageal cancer is responsible for over 1 million deaths annually worldwide; for patients with advanced disease treatment options are limited. Angiogenesis is an attractive therapeutic target that has been successfully exploited in other cancers. Ramucirumab, a fully humanized monoclonal antibody targeting VEGFR-2 has demonstrated efficacy as a single agent and in combination with paclitaxel in two large randomized trials (REGARD and RAINBOW) for the treatment of advanced previously treated gastroesophageal cancer. In combination with paclitaxel chemotherapy ramucirumab treated patients demonstrated increased rates of neutropenia, and ramucirumab is also associated with hypertension consistent with other antiangiogenic agents. Ramucirumab has been US FDA approved for patients with advanced gastroesophageal cancer who have progressed during or after treatment with fluoropyrimidine- or platinum-containing chemotherapy.

Identification and In Vitro Characterization of Phage-Displayed VHHs Targeting VEGF

Vascular endothelial growth factor (VEGF) is a potential target for cancer treatment because of its role in angiogenesis and its overexpression in most human cancers. Currently, anti-VEGF antibodies have been shown to be promising tools for therapeutic applications. However, large size, poor tumor penetration, immunogenicity, and production in cost- and labor-intensive conditions are major drawbacks of such agents. The antigen-binding regions of camelid single-chain antibodies (VHHs), due to their unique biophysical characteristics, offer an alternative to conventional antibodies for tumor-targeting purposes. The present study was undertaken to generate and characterize anti-VEGF VHHs from an immune VHH library using phage display. Four rounds of panning were performed, and selected VHHs were characterized using various immunological techniques. Assessment of the antigenic profile of VHHs was done using competition enzyme-linked immunosorbent assay (ELISA). Selected VHHs reacted strongly to VEGF in indirect ELISA and cross-reactivity ELISA tests. The binding affinity of three VHHs, ZFR-1, ZFR-2, and ZFR-5, ranged from 2.5 to 80 nM, and among them, ZFR-5, which was selected for proliferation assay, significantly inhibited the endothelial cell growth in a dose-dependent manner. Taken together, our results indicate that ZFR-5 and other VHHs may be promising tools in cancer research and treatment.

Critical appraisal of ramucirumab (IMC-1121B) for cancer treatment: from benchside to clinical use

Although antiangiogenic treatments have produced milestone advances in the treatment of several diseases, and have significantly extended the median survival of cancer patients, these agents share some weaknesses, including a limited impact on the overall cure rate, a fleeting effect because of redundant pathways or early appearance of resistance mechanisms, and the lack of predictive factors for treatment selection. Recent data suggest that antibodies targeting the vascular endothelial growth factor axis exert their activity through the inhibition of vascular endothelial growth factor receptor-2 phosphorylation, which has a pivotal role in the neoangiogenic process. Ramucirumab, a fully humanized monoclonal antibody specifically directed against the extracellular domain of the receptor, administered intravenously every 2 or 3 weeks, is emerging as a novel antiangiogenic opportunity. Starting with preclinical data and early clinical results, this concise review focuses on the development of the novel compound across multiple cancers (including gastrointestinal malignancies, breast cancer, lung carcinoma, and genitourinary tumors), and presents available data from randomized phase II and phase III trials. REGARD was the first phase III study to report on the efficacy of single-agent ramucirumab in patients with advanced cancer. Many other ongoing phase III trials are testing the efficacy of this interesting antiangiogenic compound as a single agent or in combination with chemotherapy in different cancer types.

Novel VEGF decoy receptor fusion protein conbercept targeting multiple VEGF isoforms provide remarkable anti-angiogenesis effect in vivo

VEGF family factors are known to be the principal stimulators of abnormal angiogenesis, which play a fundamental role in tumor and various ocular diseases. Inhibition of VEGF is widely applied in antiangiogenic therapy. Conbercept is a novel decoy receptor protein constructed by fusing VEGF receptor 1 and VEGF receptor 2 extracellular domains with the Fc region of human immunoglobulin. In this study, we systematically evaluated the binding affinity of conbercept with VEGF isoforms and PlGF by using anti-VEGF antibody (Avastin) as reference. BIACORE and ELISA assay results indicated that conbercept could bind different VEGF-A isoforms with higher affinity than reference. Furthermore, conbercept could also bind VEGF-B and PlGF, whereas Avastin showed no binding. Oxygen-induced retinopathy model showed that conbercept could inhibit the formation of neovasularizations. In tumor-bearing nude mice, conbercept could also suppress tumor growth very effectively in vivo. Overall, our study have demonstrated that conbercept could bind with high affinity to multiple VEGF isoforms and consequently provide remarkable anti-angiogenic effect, suggesting the possibility to treat angiogenesis-related diseases such as cancer and wet AMD etc.