In the treatment of neovascular age-related macular degeneration (AMD), vascular endothelial growth factor (VEGF) has emerged as a key target of therapy. Currently, patients with neovascular AMD are treated with monthly intravitreal injections of anti-VEGF medications. Aflibercept is a novel recombinant fusion protein engineered to bind all isoforms of VEGF-A, VEGF-B, and placental growth factor. It is the latest medication to receive US Federal Drug Administration (FDA) approval for the treatment of neovascular AMD. Theoretical models suggest this molecule may have a longer duration of action compared with current treatments. The results of the VEGF Trap-Eye: Investigation of Efficacy and Safety in wet Age-related Macular Degeneration studies (VIEW 1 and VIEW 2) support this by demonstrating that aflibercept, dosed every 2 months after a monthly loading dose for 3 months, was noninferior in the proportion of patients who maintained or improved vision at 52 weeks compared with monthly injections of ranibizumab. These results were maintained over the 2 years of the studies. Aflibercept (Eylea; Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA and Bayer, Basel, Switzerland) was approved by the FDA for the treatment of neovascular AMD on 18 November 2011.
aflibercept; neovascular age-related macular degeneration; ranibizumab; vascular endothelial growth factor; wet age-related macular degeneration
Agents such as aflibercept, which target the angiogenic pathway, are of great interest as candidates for the management of metastatic differentiated thyroid cancer. Here, we report a patient who developed a hemorrhagic abdominal pseudoaneurysm shortly after being started on this drug.
The patient was a 67-year-old woman being treated with single agent aflibercept (VEGF-Trap) for metastatic thyroid cancer. She had no history of intra-abdominal pathology or vascular disease but had been previously treated with sorafenib. Twelve days after receiving her second dose of aflibercept, she developed vague abdominal pain, which increased in severity and was accompanied by nausea and vomiting. Her symptoms progressed along with a decline in her hematocrit and signs of internal hemorrhaging. An angiogram identified an occluded celiac artery with increased collaterals and a bleeding pseudoaneurysm in the inferior pancreaticoduodenal artery. After the pseudoaneurysm was coiled, the patient stabilized.
Summary and Conclusions
Anti-angiogenic agents, usually well tolerated, can disrupt the delicate balance of normal endothelium, leading to hemorrhagic and thrombotic complications. The hemorrhage of aberrant vasculature should be included in the differential diagnosis in patients presenting with vague complaints while being treated with anti-angiogenic agents.
Pharmacological inhibition of VEGF-A has proven to be effective in inhibiting angiogenesis and vascular leak associated with cancers and various eye diseases. However, little information is currently available on the binding kinetics and relative biological activity of various VEGF inhibitors. Therefore, we have evaluated the binding kinetics of two anti-VEGF antibodies, ranibizumab and bevacizumab, and VEGF Trap (also known as aflibercept), a novel type of soluble decoy receptor, with substantially higher affinity than conventional soluble VEGF receptors. VEGF Trap bound to all isoforms of human VEGF-A tested with subpicomolar affinity. Ranibizumab and bevacizumab also bound human VEGF-A, but with markedly lower affinity. The association rate for VEGF Trap binding to VEGF-A was orders of magnitude faster than that measured for bevacizumab and ranibizumab. Similarly, in cell-based bioassays, VEGF Trap inhibited the activation of VEGFR1 and VEGFR2, as well as VEGF-A induced calcium mobilization and migration in human endothelial cells more potently than ranibizumab or bevacizumab. Only VEGF Trap bound human PlGF and VEGF-B, and inhibited VEGFR1 activation and HUVEC migration induced by PlGF. These data differentiate VEGF Trap from ranibizumab and bevacizumab in terms of its markedly higher affinity for VEGF-A, as well as its ability to bind VEGF-B and PlGF.
Electronic supplementary material
The online version of this article (doi:10.1007/s10456-011-9249-6) contains supplementary material, which is available to authorized users.
VEGF receptor; Aflibercept; Affinity; Age-related macular degeneration; Placental growth factor; Biomedicine; Cardiology; Biomedicine general; Ophthalmology; Cancer Research; Cell Biology; Oncology
Vascular endothelial growth factor (VEGF) is a key upstream mediator of tumor angiogenesis, and blockade of VEGF can inhibit tumor angiogenesis and decrease tumor growth. However, not all tumors respond well to anti-VEGF therapy. Despite much effort, identification of early response biomarkers that correlate with long-term efficacy of anti-VEGF therapy has been difficult. These difficulties arise in part because the functional effects of VEGF inhibition on tumor vessels are still unclear. We therefore assessed rapid molecular, morphologic and functional vascular responses following treatment with aflibercept (also known as VEGF Trap or ziv-aflibercept in the United States) in preclinical tumor models with a range of responses to anti-VEGF therapy, including Colo205 human colorectal carcinoma (highly sensitive), C6 rat glioblastoma (moderately sensitive), and HT1080 human fibrosarcoma (resistant), and correlated these changes to long-term tumor growth inhibition. We found that an overall decrease in tumor vessel perfusion, assessed by dynamic contrast-enhanced ultrasound (DCE-US), and increases in tumor hypoxia correlated well with long-term tumor growth inhibition, whereas changes in vascular gene expression and microvessel density did not. Our findings support previous clinical studies showing that decreased tumor perfusion after anti-VEGF therapy (measured by DCE-US) correlated with response. Thus, measuring tumor perfusion changes shortly after treatment with VEGF inhibitors, or possibly other anti-angiogenic therapies, may be useful to predict treatment efficacy.
VEGF blockade; Tumor perfusion; Tumor growth response; Preclinical model; Response biomarker
Wet age-related macular degeneration (AMD) is the most common reason for vision loss in the United States. Many treatments, such as laser therapy and photodynamic therapies, have been used but their efficacy is limited. Emerging anti-vascular endothelial growth factor (VEGF) therapies are now considered the standard of care. Anti-VEGF agents inhibit angiogenesis in the eye by suppressing abnormal blood vessel growth, leading to vision improvement. Ranibizumab and bevacizumab are two examples of anti-VEGF drugs that have been approved; both showed promise based on the visual acuity scale. Aflibercept, another new therapy known to trap VEGF and inhibit multiple growth factors, is promising not only because it can be taken bimonthly based on year 1 of the VIEW trials, but it can also be extended, as demonstrated in year 2 of the VIEW trials. Based on a cost–effect analysis, aflibercept is comparable to other leading therapies. This is a review of relevant clinical trials that have proven the non-inferiority and safety of aflibercept compared to the standard of care and its unique role in the current management of wet AMD.
aflibercept; VEGF; anti-VEGF; pegatanib; bevacizumab; ranibizumab; VIEW trials
Antivascular endothelial growth factor (anti-VEGF) therapy is a promising treatment approach for patients with recurrent glioblastoma. This single-arm phase II study evaluated the efficacy of aflibercept (VEGF Trap), a recombinantly produced fusion protein that scavenges both VEGF and placental growth factor in patients with recurrent malignant glioma.
Patients and Methods
Forty-two patients with glioblastoma and 16 patients with anaplastic glioma who had received concurrent radiation and temozolomide and adjuvant temozolomide were enrolled at first relapse. Aflibercept 4 mg/kg was administered intravenously on day 1 of every 2-week cycle.
The 6-month progression-free survival rate was 7.7% for the glioblastoma cohort and 25% for patients with anaplastic glioma. Overall radiographic response rate was 24% (18% for glioblastoma and 44% for anaplastic glioma). The median progression-free survival was 24 weeks for patients with anaplastic glioma (95% CI, 5 to 31 weeks) and 12 weeks for patients with glioblastoma (95% CI, 8 to 16 weeks). A total of 14 patients (25%) were removed from the study for toxicity, on average less than 2 months from treatment initiation. The main treatment-related National Cancer Institute Common Terminology Criteria grades 3 and 4 adverse events (38 total) included fatigue, hypertension, and lymphopenia. Two grade 4 CNS ischemias and one grade 4 systemic hemorrhage were reported. Aflibercept rapidly decreases permeability on dynamic contrast enhanced magnetic resonance imaging, and molecular analysis of baseline tumor tissue identified tumor-associated markers of response and resistance.
Aflibercept monotherapy has moderate toxicity and minimal evidence of single-agent activity in unselected patients with recurrent malignant glioma.
Vascular endothelial growth factor (VEGF) Trap (aflibercept) is an angiogenesis inhibitor comprising portions of the extracellular domains of human VEGF receptors 1 and 2 fused to the Fc portion of human immunoglobulin G. This phase I study was designed to evaluate the safety, pharmacokinetics, and pharmacodynamics of VEGF Trap administered intravenously (IV) every 2 weeks.
Patients and Methods
Patients with refractory solid tumors or non-Hodgkin's lymphoma with adequate organ function were eligible. Pharmacokinetic/pharmacodynamic markers included measurement of plasma VEGF bound to VEGF Trap and free VEGF Trap. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was incorporated to measure the biologic effects of the drug on tumor vascularity and permeability.
The study enrolled 47 patients at doses ranging from 0.3 to 7.0 mg/kg IV every 2 weeks. Dose-limiting toxicities were rectal ulceration and proteinuria at the 7.0 mg/kg dose. Other mechanism-specific toxicities included hypertension. On the basis of these observations and on pharmacokinetics, the recommended phase II dose of VEGF Trap as a single agent is 4 mg/kg every 2 weeks. Three RECIST (Response Evaluation Criteria in Solid Tumors) –defined partial responses were observed, one at the 3.0 mg/kg and two at the 7.0 mg/kg dose level. Maximum plasma concentration of free VEGF Trap increased proportionally with dose. Maximal VEGF-bound VEGF Trap complex levels were reached at doses ≥ 2.0 mg/kg. Changes in volume transfer constant measured by DCE-MRI at baseline and at 24 hours after administration indicate a possible dose-related change in this pharmacodynamic marker.
IV VEGF Trap was well tolerated at the dose levels tested. Pharmacodynamic and pharmacokinetic markers were indicative of VEGF blockade.
Aflibercept, an intravenously administered anti-VEGF and antiplacental growth factor (PlGF) agent, has recently been approved by the U.S. Food and Drug Administration in combination with 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) for the treatment of patients with metastatic colorectal cancer who have previously received an oxaliplatin-containing chemotherapy regimen. In the phase III VELOUR trial, aflibercept plus FOLFIRI statistically significantly prolonged both progression-free survival (PFS; median PFS for the aflibercept plus FOLFIRI arm was 6.90 vs. 4.67 months for the placebo-plus-FOLFIRI arm) and overall survival (median overall survival for the aflibercept-plus-FOLFIRI arm was 13.50 vs. 12.06 months for the placebo plus FOLFIRI arm), but grade 3 or 4 adverse events were more common with the addition of aflibercept. However, the addition of aflibercept to 5-fluorouracil, leucovorin, and oxaliplatin (mFOL-FOX6) in the phase II AFFIRM trial of first-line treatment of mCRC failed to improve PFS or response rate. As a decoy VEGF receptor, aflibercept (VEGF-Trap) has binding affinity for VEGF-A, VEGF-B, PlGF-1, and PlGF-2, and this is a mechanism of significant interest. Optimal strategies for incorporating aflibercept into treatment regimens that include other anti-VEGF and cytotoxic chemotherapeutic agents, as well as development of predictive biomarkers for treatment response, have yet to be defined.
Anti-vascular therapy directed against VEGF or its receptors has been successful when administered at early stages of tumor vessel growth, but is less effective when administered later. Tumor blood vessels are heterogeneous, so vessel subpopulations may differ in their requirements for tumor cell-secreted VEGF and in their susceptibility to anti-VEGF/VEGFR therapy. Human cancers contain several distinct blood vessel types, including mother vessels (MV), glomeruloid microvascular proliferations (GMP), vascular malformations (VM), feeding arteries (FA) and draining veins (DV), all of which can be generated in mice in the absence of tumor cells using expression vectors for VEGF-A164. In this study, we investigated the sensitivity of each of these vessel types to anti-VEGF therapy with aflibercept ® (VEGF Trap), a potent inhibitor of VEGF-A164. Administering VEGF Trap treatment before or shortly after injection of a recombinant VEGF-A164 expressing adenovirus could prevent or regress tumor-free neovasculature, but it was progressively less effective if initiated at later times. Early-forming MVs and GMPs in which the lining endothelial cells expressed high levels of VEGFR-2 were highly susceptible to blockade by VEGF Trap. In contrast, late-forming VMs, FAs, and DVs that expressed low levels of VEGFR-2 were largely resistant. Together, our findings define the susceptibility of different blood vessel subtypes to anti-VEGF therapy, offering a possible explanation for the limited effectiveness of anti-VEGF-A/VEGFR treatment of human cancers, which are typically present for months to years before discovery and are largely populated by late-forming blood vessels.
Angiogenesis; Arterio-venogenesis; Ad-VEGF-A164; VEGF; Aflibercept (VEGF Trap)
Vascular endothelial growth factor (VEGF) is a naturally occurring glycoprotein in the body that acts as a growth factor for endothelial cells. It regulates angiogenesis, enhances vascular permeability, and plays a major role in wet age-related macular degeneration. The consistent association between choroidal neovascularization and increased VEGF expression provides a strong reason for exploring the therapeutic potential of anti-VEGF agents in the treatment of this disorder. Blockade of VEGF activity is currently the most effective strategy for arresting choroidal angiogenesis and reducing vascular permeability, which is frequently the main cause of visual acuity deterioration. In recent years, a number of other molecules have been developed to increase the efficacy and to prolong the durability of the anti-VEGF effect. Aflibercept (EYLEA®; Regeneron Pharmaceutical Inc and Bayer), also named VEGF Trap-eye, is the most recent member of the anti-VEGF armamentarium that was approved by the US Food and Drug Administration in November 2011. Because of its high binding affinity and long duration of action, this drug is considered to be a promising clinically proven anti-VEGF agent for the treatment of wet maculopathy.
This article reviews the current literature and clinical trial data regarding the efficacy and the pharmacological properties of VEGF-Trap eye and describes the possible advantages of its use over the currently used “older” anti-VEGF drugs.
For this review, a search of PubMed from January 1989 to May 2013 was performed using the following terms (or combination of terms): vascular endothelial growth factors, VEGF, age-related macular degeneration, VEGF-Trap eye in wet AMD, VEGF-Trap eye in diabetic retinopathy, VEGF-Trap eye in retinal vein occlusions, aflibercept. Studies were limited to those published in English.
Results and conclusion
Two Phase III clinical trials, VEGF Trap-eye Investigation of Efficacy and Safety in Wet AMD (VIEW) 1 and 2, comparing VEGF Trap-eye to ranibizumab demonstrated the noninferiority of this novel compound. The clinical equivalence of this compound against ranibizumab is maintained even when the injections are administered at 8-week intervals, which indicates the potential to reduce the risk of monthly intravitreal injections and the burden of monthly monitoring.
aflibercept; AMD; neovascularization; VEGF; VEGF inhibition; VEGF-Trap eye
Significant progression has been achieved in the treatment of metastatic colorectal cancer (mCRC) in recent years. This has been partly attributed to successfully incorporating new drugs into combination chemotherapy. In addition to the traditional cytotoxic chemotherapeutic agents, molecularly targeted agents began to play an important role in the treatment of advanced solid tumors. To date, two classes of molecularly targeted agents have been approved for treatment of patients with mCRC: (1) antivascular endothelial growth factor (anti-VEGF) agents (such as bevacizumab and aflibercept) and (2) antiendothelial cell growth factor receptor (anti-EGFR) agents (such as cetuximab and panitumumab). Aflibercept is a new member of anti-VEGF agents which has demonstrated efficacy for treatment of mCRC. With the commencement of clinical trials and basic research into aflibercept, more data from the bedside and the bench have been obtained. This review will outline the application of anti-VEGF agents by reviewing clinic experiences of bevacizumab and aflibercept, and try to add perspectives on the use of anti-VEGF agents in mCRC.
chemotherapy; tumors; antiangiogenic
Angiogenesis is a hallmark of malignant transformation. With improved understanding of angiogenic signaling in both the normal and malignant state, there have been a number of agents developed that target VEGF signaling. These targeted agents can affect downstream VEGF signal transduction via unique mechanisms at different cellular and extracellular locations. The aflibercept, or VEGF-Trap, molecule is the subject of this article. Its molecular structure, pharmacokinetic and pharmacodynamic profile, and preclinical and early clinical data in epithelial ovarian carcinoma is reviewed. For comparison, other anti-angiogenic agents that have been or are currently being studied in epithelial ovarian carcinoma are also summarized. Finally, the anticipated role of aflibercept in the treatment of epithelial ovarian carcinoma is also discussed.
aflibercept; antiangiogenesis; epithelial ovarian carcinoma; vascular endothelial growth factor; VEGF-Trap
Vascular endothelial growth factor (VEGF) plays an important role in both physiologic and pathologic angiogenesis and contributes to increased permeability across both the blood-retinal and blood-brain barriers. After 2 decades of extensive research into the VEGF families and receptors, specific molecules have been targeted for drug development, and several medications have received US Food and Drug Administration approval. Bevacizumab, a full-length antibody against VEGF approved for the intravenous treatment of advanced carcinomas, has been used extensively in ophthalmology for exudative age-related macular degeneration, diabetic retinopathy, retinal vein occlusions, retinopathy of prematurity, and other chorioretinal vascular disorders. Pegaptanib and ranibizumab have been developed specifically for intraocular use, whereas the soon-to-be-introduced aflibercept (VEGF Trap-Eye) is moving through clinical trials for both intraocular and systemic use. Although these drugs exhibit excellent safety profiles, ocular and systemic complications, particularly thromboembolic events, remain a concern in patients receiving therapy. Patients experiencing adverse events that may be related to VEGF suppression should be carefully evaluated by both the ophthalmologist and the medical physician to reassess the need for intraocular therapy and explore the feasibility of changing medications. For this review a search of PubMed from January 1, 1985 through April 15, 2011, was performed using the following terms (or combination of terms): vascular endothelial growth factors, VEGF, age-related macular degeneration, diabetic retinopathy, retina vein occlusions, retinopathy of prematurity, intravitreal injections, bevacizumab, ranibizumab, and VEGF Trap. Studies were limited to those published in English. Other articles were identified from bibliographies of retrieved articles and archives of the author.
This phase I cohort study investigated aflibercept (vascular endothelial growth factor (VEGF) trap) plus docetaxel and cisplatin in patients with advanced solid tumours.
Patients received intravenous aflibercept 4, 5, or 6 mg kg−1 with docetaxel and cisplatin (75 mg m−2 each) on day 1 of a 3-week cycle until progressive disease or unacceptable toxicity. Primary objectives were determining cycle 1 dose-limiting toxicities (DLTs) and the aflibercept recommended phase II trial dose (RP2D) for this combination.
During the dose-escalation phase (n=16), there were two DLTs of febrile neutropenia (at 4 and 5 mg kg−1). Granulocyte colony-stimulating factor prophylaxis was subsequently recommended. The RP2D of aflibercept was established at 6 mg kg−1 and administered to 14 additional patients. The most frequent grade 3/4 adverse events (AEs) were neutropenia (43.3%), stomatitis (20.0%), asthenia/fatigue (20.0%), and hypertension (16.7%). All-grade AEs associated with VEGF blockade included epistaxis (83.3%), dysphonia (70.0%), proteinuria (53.3%), and hypertension (50.0%). There were five partial responses (16.7%) and 18 cases of stable disease (60.0%) (lasting >3 months in 10 patients). There were no pharmacokinetic (PK) interactions between the three drugs.
Aflibercept 6 mg kg−1 with docetaxel and cisplatin 75 mg m−2 every 3 weeks is the RP2D based on tolerability, antitumour activity, and PKs.
aflibercept; VEGF trap; angiogenesis; anti-VEGF therapy
Angiogenesis is an established target for the treatment of MBC. Aflibercept (VEGF-Trap) is a humanized fusion protein, which binds VEGF-A, VEGF-B, and PIGF-1 and -2.
Patients and Methods
A 2-stage phase II study with primary end points of confirmed tumor response and 6-month progression-free survival (PFS). If either end point was promising after the initial 21 patients, an additional 20 patients would be enrolled. Measurable disease, <2 previous chemotherapy treatments, previous anthracycline or taxane therapy, and Eastern Cooperative Oncology Group performance status of 0 or 1 were required. Aflibercept was given at a dose of 4 mg/kg intravenous every 14 days.
Twenty-one patients were enrolled; 71% had visceral disease, 57% were estrogen receptor negative, 19% had HER2+ disease with previous trastuzumab treatment, and 33% had 2 previous chemotherapy regimens. Partial response rate was 4.8% (95% confidence interval [CI], 0.1%–23.8%) and 6-month PFS was 9.5% (95% CI, 1.2%–30.4%). Neither primary end point met efficacy goals and the study was terminated. A median of 3 cycles was given. Median PFS was 2.4 months. Common grade 3 or 4 adverse events were hypertension (33%), fatigue (19%), dyspnea (14%), and headache (14%). Two cases of severe left ventricular dysfunction were noted.
Aflibercept did not meet efficacy goals in patients previously treated with MBC. Toxicity was as expected for anti-VEGF therapy.
Angiogenesis; Cooperative group; Monoclonal antibody; Breast cancer
Macular degeneration is the leading cause of blindness in developed countries. In the treatment of neovascular age-related macular degeneration, vascular endothelial growth factor (VEGF) has emerged as a key target for therapy. The intravitreal injection of anti-VEGF drugs has been widely employed to reduce the disease progression and improve the visual outcomes of the affected patients. However, each intravitreal inoculation poses a risk of several complications as infection, inflammation, endophthalmitis, intraocular inflammation, increase of intraocular pressure and vitreous hemorrhage. This short review evaluates the efficacy and the incidence of adverse drug reactions related to intravitreal administration of the main anti-VEGF drugs actually available: Bevacizumab, ranibizumab and aflibercept.
Adverse drug reactions; aflibercept; age-related macular degeneration; bevacizumab; choroidal neovascularization; ranibizumab
Angiogenesis plays an important role in normal animal growth and development. This process is also vital for the growth of tumors. Angiogenesis inhibitors have a different mechanism of action to traditional chemotherapy agents and radiation therapy. The angiogenesis inhibitors can act synergistically with conventional treatments and tend to have non-overlapping toxicities. There are four drugs which have a proven role in treating cancer patients. Bevacizumab is a humanized monoclonal antibody that binds to and neutralizes vascular endothelial growth factor (VEGF). Sunitinib and sorafenib inhibit multiple tyrosine kinase receptors that are important for angiogenesis. Thalidomide inhibits the activity of basic fibroblast growth factor-2 (bFGF). The licensed indications and the supporting evidence are discussed. Other drugs are currently being tested in clinical trials and the most promising of these drugs are discussed. Aflibercept, also known as VEGF-trap, is a recombinant fusion protein that binds to circulating VEGF. The vascular disrupting agents act by targeting established blood vessels. These exciting new treatments have the potential to transform the management of cancer.
angiogenesis; bevacizumab; tyrosine kinase inhibitors; thalidomide; aflibercept; vascular disrupting agents
Inhibition of angiogenesis is an established adjunct in the treatment of metastatic colorectal cancer. Bevacizumab, a monoclonal antibody that binds to vascular endothelial growth factor (VEGF) A, improves clinical outcomes when added to standard chemotherapy for metastatic colorectal cancer. Unfortunately, the development of resistance is inevitable, and novel therapeutic strategies are needed. Aflibercept is an intravenously administered fusion protein of the human vascular endothelial growth factor receptor 1 (VEGFR1) and VEGFR2 extracellular domains. This antiangiogenic agent binds to VEGF A, VEGF B, and placental growth factor 1 (PlGF1) and PlGF2 with high affinity and inhibits downstream signaling. Common side effects of single agent aflibercept are similar to other antiangiogenic drugs and include hypertension, proteinuria, fatigue, and headache. Recent clinical data regarding the efficacy of aflibercept with standard chemotherapy for metastatic colorectal cancer, associated adverse events, and future areas of research are reviewed.
aflibercept; angiogenesis; metastatic colorectal cancer
Targeting angiogenesis is a valid anti-cancer strategy. Aflibercept is designed to sequester circulating vascular endothelial growth factor (VEGF) by preventing VEGF from binding to its receptors. This phase I study was to evaluate a new formulation of subcutaneously administered aflibercept in patients with advanced solid tumors. Here we report our experience with the toxicity, pharmacokinetic profile and efficacy of the new 100 mg/mL subcutaneous (SC) formulation of aflibercept administered at a dose of at 4 mg/kg every 2 weeks.
Phase I study; Aflibercept; Angiogenesis inhibitor; Subcutaneously administration
Vascular endothelial growth factor (VEGF) A is a major promoter of tumor angiogenesis and a prime target of antiangiogenic cancer therapy. To examine whether endothelial cell signaling might provide histological biomarkers of angiogenesis and VEGF activity in vivo, normal mouse organs and multiple tumor models were studied immunohistochemically for endothelial expression of activated ERK, STAT3 and AKT. Phospho(p)-ERK and p-STAT3 expression was negligible in the endothelia of normal organs but was significantly elevated in tumor endothelium. p-AKT was present at significant and comparable levels in both tumor and normal endothelia. In K1735 tumors induced to express more VEGF, endothelial p-ERK, p-STAT3 and p-AKT increased accompanied by signs of accelerated angiogenesis. Treatment of K1735 and Colo-205 tumors with the VEGF inhibitor, VEGF Trap (aflibercept), decreased tumor endothelial p-ERK, p-STAT3 and p-AKT expression accompanied by signs of antiangiogenic effect. These results show that endothelial p-ERK and p-STAT3 (but not p-AKT) distinguish tumor from normal vessels and that the presence of these two signaling intermediates may be useful indicators of tumor angiogenic activity and angiogenesis inhibition by VEGF antagonists.
VEGF; VEGF Trap; endothelial cells; signal transduction; angiogenesis; biomarker; p-ERK; p-STAT3; p-AKT
The aim of this systematic review is to appraise the evidence for the use of anti-VEGF drugs and steroids in diabetic macular oedema (DMO) as assessed by change in best corrected visual acuity (BCVA), central macular thickness and adverse events
MEDLINE, EMBASE, Web of Science with Conference Proceedings and the Cochrane Library (inception to July 2012). Certain conference abstracts and drug regulatory web sites were also searched.
Study eligibility criteria, participants and interventions
Randomised controlled trials were used to assess clinical effectiveness and observational trials were used for safety. Trials which assessed triamcinolone, dexamethasone, fluocinolone, bevacizumab, ranibizumab, pegaptanib or aflibercept in patients with DMO were included.
Study appraisal and synthesis methods
Risk of bias was assessed using the Cochrane risk of bias tool. Study results are narratively described and, where appropriate, data were pooled using random effects meta-analysis.
Anti-VEGF drugs are effective compared to both laser and placebo and seem to be more effective than steroids in improving BCVA. They have been shown to be safe in the short term but require frequent injections. Studies assessing steroids (triamcinolone, dexamethasone and fluocinolone) have reported mixed results when compared with laser or placebo. Steroids have been associated with increased incidence of cataracts and intraocular pressure rise but require fewer injections, especially when steroid implants are used.
The quality of included studies varied considerably. Five of 14 meta-analyses had moderate or high statistical heterogeneity.
Conclusions and implications of key findings
The anti-VEGFs ranibizumab and bevacizumab have consistently shown good clinical effectiveness without major unwanted side effects. Steroid results have been mixed and are usually associated with cataract formation and intraocular pressure increase. Despite the current wider spectrum of treatments for DMO, only a small proportion of patients recover good vision (≥20/40), and thus the search for new therapies needs to continue.
Angiogenesis is essential for the growth and metastasis of cancer. Although anti-angiogenic agents, particularly vascular endothelial growth factor (VEGF) inhibitors, have exhibited single-agent activity, there is considerable interest in combining these novel drugs with conventional chemotherapy reagents to achieve an optimal clinical efficacy. The objective of this study was to evaluate the benefits of the combination therapy of vascular endothelial growth factor trap (VEGF-Trap) with gemcitabine in a lung tumor model.
A luciferase-expressing Lewis lung carcinoma (LLC) model was established in C57BL/6J mice and tumor-bearing mice were randomized into control, VEGF-Trap, gemcitabine and VEGF-Trap/gemcitabine combination groups. Tumor growth and animal survival were monitored. Tumor microvessel density and cell proliferation were evaluated by CD31 and Ki-67 immunohistochemical analysis. TUNEL assay was performed to detect apoptotic cells. The protein levels of Cyclin D1, Pro-Caspase-3, Bcl-2, MMP2 and MMP9 in tumor extracts were examined by western blot.
VEGF-Trap in combination with gemcitabine showed significantly enhanced inhibition of tumor growth and prolonged mouse survival compared to the VEGF-Trap or gemcitabine monotherapy. The VEGF-Trap/gemcitabine combination therapy not only potently inhibited tumor angiogenesis and cell proliferation, but also increased cellular apoptosis within tumor tissues. In addition, the combination treatment markedly down-regulated the expression of proliferation, anti-apoptosis and invasion related proteins.
Combination therapy using VEGF-Trap and gemcitabine resulted in improved anti-tumor efficacy in a lung cancer model and VEGF-Trap/gemcitabine combination might represent a promising strategy in the treatment of human lung cancer.
The aim of this multi-institutional non randomized phase II trial was to determine the efficacy and safety of single agent aflibercept (VEGF Trap), a recombinant fusion protein that blocks multiple vascular endothelial growth factor isoforms, in women with gynecologic soft tissue sarcoma.
Patients were enrolled in two cohorts each with Simon two stage designs: uterine leiomyosarcoma and carcinosarcoma of endometrial, ovarian or fallopian tube origin. Eligibility criteria included ≤ 2 prior lines of chemotherapy for metastatic disease and ECOG performance status ≤ 2. Aflibercept 4 mg/kg was administered intravenously on day 1 of a 14 day cycle. Primary endpoints were objective response and disease stabilization (Progression Free Survival (PFS) at 6 months).
41 patients with uterine leiomyosarcoma and 22 patients with carcinosarcoma (19 uterine, 3 ovarian) were enrolled on study. In the leiomyosarcoma cohort, eleven (27%) patients had stable disease (SD), 4 with SD lasting at least 24 weeks. The 6 month PFS was 17%, with median time to progression (TTP) of 1.8 (95% CI:1.6–2.1) months. In the carcinosarcoma cohort, two (9%) patients had SD, one lasting > 24 weeks, median TTP was 1.6 months (95%CI: 1.1–1.7) No partial responses were observed in patients from either cohort. Grade 3 or more aflibercept related toxicity was uncommon and included hypertension, fatigue, headache and abdominal pain.
Single agent aflibercept has modest activity in patients with uterine leiomyosarcoma and minimal activity in women with carcinosarcoma.
Vascular endothelial growth factor (VEGF) is a potent promoter of angiogenesis involved in a wide variety of physiologic processes. Intravitreal injections targeting VEGF have transformed the treatment of neovascular retinal diseases. Currently, there are four anti-VEGF agents in use: bevacizumab, ranibizumab, pegaptanib, and aflibercept. The success and frequency of anti-VEGF therapy have made the ocular safety profile of these agents of vital importance. This paper focuses on sterile endophthalmitis. In this paper, we compare the incidences of posttreatment sterile endophthalmitis among the four agents, review the mechanism of actions, and discuss the most prevalent hypotheses leading to sterile endophthalmitis.
Inhibition of tumor angiogenesis has emerged as an important therapeutic component in the management of metastatic colorectal cancer. Three anti-angiogenic agents are currently approved in this clinical setting: bevacizumab, ziv-aflibercept, and regorafenib. Bevacizumab, a monoclonal antibody that targets the angiogenesis-driving ligand vascular endothelial growth factor A (VEGF-A), is the only anti-angiogenic agent approved in first-line therapy for metastatic colorectal cancer, where it can be used in combination with intravenous 5-fluorouracil-containing chemotherapy regimens. In conjunction with second-line chemotherapies, bevacizumab also has anti-cancer activity, both for the management of metastatic colorectal cancer in patients who received it as a part of their first line therapy and for those who are naïve to it. Ziv-aflibercept also has demonstrated clinical activity in conjunction with the chemotherapeutic regimen FOLFIRI in the second line management of patients with metastatic colorectal cancer; it functions by binding VEGF-A to the vascular endothelial growth factor proteins VEGF-B and PIGF (placental growth factor). Regorafenib, which inhibits multiple tyrosine kinases, including the VEGF receptors, has proven clinical benefit in the management of patients with metastatic colorectal cancer refractory to all other therapies. For patients’ whose cancers are refractory to all other therapies, there is also evidence for the use of bevacizumab with fluoropyrimidine monotherapy, but only in the bevacizumab-naïve patient subset. Presently, it is not clear if any one agent as more activity in a particular line of therapy than another, has greater efficacy when paired with a particular chemotherapy backbone, or if a particular patient subset is more likely to benefit from these agents. Given the present benefit and tolerance data, an anti-angiogenic agent should be considered in all lines of therapy in the management of metastatic colorectal cancer, with the evidence for the use of these agents in each specific line of therapy and in specific chemotherapeutic combinations driving agent selection.
Colorectal cancer; metastatic; angiogenesis; bevacizumab; ziv-aflibercept; regorafenib