Aflibercept (AVE0005): an alternative strategy for inhibiting tumour angiogenesis by vascular endothelial growth factors

A phase two trial evaluating FOLFIRI plus aflibercept after failure of FOLFOXIRI plus bevacizumab in patients with unresectable metastatic colorectal cancer

BACKGROUND

FOLFOXIRI plus bevacizumab (BEV) is an option for first-line treatment of metastatic colorectal cancer (mCRC). However, there is no consensus on the optimal treatment strategy when disease progresses. The EFFORT open-label, multicenter, single-arm phase II study investigated whether FOLFIRI plus aflibercept retains activity after progression of FOLFOXIRI plus BEV treatment.

METHODS

The patients with unresectable mCRC who failed first-line FOLFOXIRI plus BEV received FOLFIRI plus aflibercept. The primary endpoint was progression-free survival (PFS) in the full analysis set (FAS). Angiogenic biomarkers were measured before treatment initiation.

RESULTS

From April 2019 to May 2021, 35 patients were enrolled and 34 were analysed in the FAS population (men, 18; median age, 63 years [range: 32-78]). The primary tumor was left-sided in most cases (23/34), 23 patients were RAS mutant, 3 patients had BRAF V600E mutation and 27 patients had liver metastases. The primary end-point was met with a median PFS of 4.3 months [80% confidence interval [CI] 3.7-5.1]. Median overall survival was 15.2 months [95% CI 8.9-22.7]. Per RECIST, there were 1 complete response, 4 partial responses, 21 stable diseases and 8 disease progressions. Overall response rate was 14.7% [95% CI 5.0-31.1], and disease control rate was 76.5% [95% CI 58.8-89.3]. Responses were more common in patients with high VEGF-C, low VEGF-D and low PlGF levels before treatment.

CONCLUSION

FOLFIRI plus aflibercept, administered after failure of FOLFOXIRI plus BEV, is effective and has a manageable safety profile. This regimen may be a useful second-line treatment option for these patients.

From Deep Learning to the Discovery of Promising VEGFR-2 Inhibitors

Vascular endothelial growth factor receptor 2 (VEGFR-2) stands as a prominent therapeutic target in oncology, playing a critical role in angiogenesis, tumor growth, and metastasis. FDA-approved VEGFR-2 inhibitors are associated with diverse side effects. Thus, finding novel and more effective inhibitors is of utmost importance. In this study, a deep learning (DL) classification model was first developed and then employed to select putative active VEGFR-2 inhibitors from an in-house chemical library including 187 druglike compounds. A pool of 18 promising candidates was shortlisted and screened against VEGFR-2 by using molecular docking. Finally, two compounds, RHE-334 and EA-11, were prioritized as promising VEGFR-2 inhibitors by employing PLATO, our target fishing and bioactivity prediction platform. Based on this rationale, we prepared RHE-334 and EA-11 and successfully tested their anti-proliferative potential against MCF-7 human breast cancer cells with IC50 values of 26.78±4.02 and 38.73±3.84 μM, respectively. Their toxicities were instead challenged against the WI-38. Interestingly, expression studies indicated that, in the presence of RHE-334, VEGFR-2 was equal to 0.52±0.03, thus comparable to imatinib equal to 0.63±0.03. In conclusion, this workflow based on theoretical and experimental approaches demonstrates effective in identifying VEGFR-2 inhibitors and can be easily adapted to other medicinal chemistry goals.

The Clinical Impact of Vascular Endothelial Growth Factor/Receptor (VEGF/R) Inhibitors on Voice

Background. Vascular endothelial growth factor/receptor (VEGF/R) inhibitors are used in chemotherapy protocols to limit tumor angiogenesis. Recent evidence shows they are associated with hoarseness, but their impact on vocal cord function has not been fully identified. Objectives. To describe the preliminary laryngeal findings in patients undergoing chemotherapy with VEGF/R inhibitors, and to describe possible mechanisms of their effect on vocal fold function. Methods. A retrospective case series was conducted in a tertiary medical center between July 2008 and August 2022. Cancer patients developing hoarseness while undergoing chemotherapy with VEGF/R inhibitors underwent videolaryngostroboscopy. Results. The study included four patients. There were three females and one male, treated for breast, lung, and unknown primary cancer, respectively. All 4 patients developed hoarseness 2–7 days after initiating treatment with the VEGF/R inhibitor drugs aflibercept (n = 1) and bevacizumab (n = 3). In all patients, videolaryngostroboscopy revealed vocal fold bowing and pronounced glottic insufficiency. There were no signs of mucositis or paralysis. In three patients, treatment involved speech therapy, with or without vocal fold augmentation. The average follow-up was 10 months (range 8–12 months). In 2 patients, there was a return of normal voice quality with resolution of vocal fold bowing. In one patient, who remained on chemotherapy, there was persistent bowing. Conclusions. VEGF/R inhibitors are associated with vocal fold bowing and glottic insufficiency. This appears to be a reversible side effect. To our knowledge, this is only the second clinical description of the effect of VEGF/R inhibitors on vocal fold function.

Current Targeted Therapy for Metastatic Colorectal Cancer

Colorectal cancer (CRC) is the third most common type of cancer and the second leading cause of cancer deaths worldwide. Surgery or surgery plus radiotherapy and/or chemotherapy for patients with metastatic CRC (mCRC) were accepted as the main therapeutic strategies until the early 2000s, when targeted drugs, like cetuximab and bevacizumab, were developed. The use of targeted drugs in clinical practice has significantly increased patients' overall survival. To date, the emergence of several types of targeted drugs has opened new possibilities and revealed new prospects for mCRC treatment. Therapeutic strategies are continually being updated to select the most suitable targeted drugs based on the results of clinical trials that are currently underway. This review discusses the up-to date molecular evidence of targeted therapy for mCRC and summarizes the Food and Drug Administration-approved targeted drugs including the results of clinical trials. We also explain their mechanisms of action and how these affect the choice of a suitable targeted therapy.

Identification of Novel Potential VEGFR-2 Inhibitors Using a Combination of Computational Methods for Drug Discovery

The vascular endothelial growth factor receptor 2 (VEGFR-2) is largely recognized as a potent therapeutic molecular target for the development of angiogenesis-related tumor treatment. Tumor growth, metastasis and multidrug resistance highly depends on the angiogenesis and drug discovery of the potential small molecules targeting VEGFR-2, with the potential anti-angiogenic activity being of high interest to anti-cancer research. Multiple small molecule inhibitors of the VEGFR-2 are approved for the treatment of different type of cancers, with one of the most recent, tivozanib, being approved by the FDA for the treatment of relapsed or refractory advanced renal cell carcinoma (RCC). However, the endogenous and acquired resistance of the protein, toxicity of compounds and wide range of side effects still remain critical issues, which lead to the short-term clinical effects and failure of antiangiogenic drugs. We applied a combination of computational methods and approaches for drug design and discovery with the goal of finding novel, potential and small molecule inhibitors of VEGFR2, as alternatives to the known inhibitors’ chemical scaffolds and components. From studying several of these compounds, the derivatives of pyrido[1,2-a]pyrimidin-4-one and isoindoline-1,3-dione in particular were identified.

INTRAVITREAL ZIV-AFLIBERCEPT FOR NEOVASCULAR AGE-RELATED MACULAR DEGENERATION: 52-Week Results

PURPOSE

To evaluate the 52-week safety and efficacy of intravitreal ziv-aflibercept in patients with neovascular age-related macular degeneration.

METHODS

All patients received three monthly intravitreal injections of 0.05 mL of ziv-aflibercept (1.25 mg) followed by a pro re nata regimen. The best-corrected visual acuity and spectral domain optical coherence tomography were obtained at baseline and monthly. Full-field and multifocal electroretinograms were obtained at baseline and 4, 13, 26, and 52 weeks. For some full-field electroretinography parameters, we calculated the differences between baseline and 52 weeks and then compared those differences between treated and untreated fellow eyes.

RESULTS

Fifteen patients were included and 14 completed the 52-week follow-up. The mean best-corrected visual acuity improved from 0.95 ± 0.41 (20/200) at baseline to 0.75 ± 0.51 (20/125) logarithm of the minimum angle of resolution at 52 weeks (P = 0.0066). The baseline central retinal thickness decreased from 478.21 ± 153.48 μm to 304.43 ± 98.59 μm (P = 0.0004) at 52 weeks. Full-field electroretinography parameters used to assess retinal toxicity after intravitreal injections (rod response and oscillatory potentials) remained unchanged during follow-up. The average multifocal electroretinography macular response in 5° showed increased N1-P1 amplitude and decreased P1 implicit time (P < 0.05). One patient presented with intraocular inflammation after the seventh intravitreal procedure.

CONCLUSION

The results suggested that intravitreal ziv-aflibercept might be safe and effective for treating neovascular age-related macular degeneration. More patients and a longer follow-up are needed to confirm the long-term outcomes of intravitreal ziv-aflibercept.

Equine hydrallantois is associated with impaired angiogenesis in the placenta

INTRODUCTION

Hydrallantois is the excessive accumulation of fluid in the allantoic cavities during the last trimester of pregnancy, leading to abdominal wall hernias, cardiovascular shock, abortion, and dystocia. It has been postulated that hydrallantois is associated with structural and/or functional changes in the chorioallantoic membrane. In the present study, we hypothesized that angiogenesis is impaired in the hydrallantoic placenta.

METHOD

Capillary density in the hydrallantoic placenta was evaluated in the chorioallantois via immunohistochemistry for Von Willebrand Factor. Moreover, the expression of angiogenic genes was compared between equine hydrallantois and age-matched, normal placentas.

RESULTS

In the hydrallantoic samples, edema was the main pathological finding. The capillary density was significantly lower in the hydrallantoic samples than in normal placentas. The reduction in the number of vessels was associated with abnormal expression of a subset of angiogenic and hypoxia-associated genes including VEGF, VEGFR1, VEGFR2, ANGPT1, eNOS and HIF1A. We believe that the capillary density and the abnormal expression of angiogenic genes leads to tissue hypoxia (high expression of HIF1A) and edema. Finally, we identified a lower expression of genes associated with steroidogenic enzyme (CYP19A1) and estrogen receptor signaling (ESR2) in the hydrallantoic placenta.

DISCUSSION

Based on the presented data, we believe that formation of edema is due to disrupted vascular development (low number of capillaries) and hypoxia in the hydrallantoic placenta. The edema leads to further hypoxia and consequently, causes an increase in vessel permeability which leads to a gradual increase in interstitial fluid accumulation, resulting in an insufficient transplacental exchange rate and accumulation of fluid in the allantoic cavity.

Osteonecrosis of the jaw in the era of targeted therapy and immunotherapy in oncology

Osteonecrosis of the jaw (ONJ) is a well-known pathological condition in oncology derived from the use of bisphosphonates (BPs) and denosumab. Many molecular and immunological targets have been introduced for daily use in cancer treatment in recent years; consequently, new cases of ONJ have been reported in association with these drugs, especially if administered with BPs and denosumab. When the drugs are administered alone, ONJ is rarely seen. The objective of our study was to analyze the recent literature relative to the association of ONJ with these new drugs highlighting the pathogenic, clinical and therapeutic aspects. The close collaboration between maxillofacial surgeon, oncologist, dentist, and dental hygienist remains the most important aspect for the prevention, prompt recognition, and treatment of this pathology.

Tumor-secreted dickkopf2 accelerates aerobic glycolysis and promotes angiogenesis in colorectal cancer

Angiogenesis is a fundamental process that involves in tumor progression and metastasis. Vascular endothelial growth factor (VEGF) family and their receptors are identified as the most prominent regulators of angiogenesis. However, the clinical efficacy of anti-VEGF/VEGFR therapy is not ideal, prompting the needs to further understand mechanisms behind tumor angiogenesis. Here, we found that Dickkopf associated protein 2 (DKK2), a secretory protein highly expressed in metastatic colorectal cancer tissues, could stimulate angiogenesis via a classic VEGF/VEGFR independent pathway. Methods: DKK2 was screened out from microarray data analyzing gene expression profiles of eight pairs of non-metastatic and metastatic human colorectal cancer (CRC) tissues. Immunofluorescence histochemical staining (IHC) was used to detect the expression of DKK2 and angiogenesis in CRC tissues. Chicken chorioallantoic membrane (CAM) assay and Human umbilical vein endothelial cells (HUVEC) tubule formation assay was used for in vitro and in vivo angiogenesis study, respectively. Lactate and glucose concentration in the culture medium was measured by enzyme-linked immunosorbent assay (ELISA). Luciferase reporter assay was used to verify the interaction between miR-493-5p and the 3'UTR of DKK2. Results: DKK2 could stimulate angiogenesis via accelerating the aerobic glycolysis of CRC cells, through which lactate is produced from glucose and accumulated in tumor microenvironment. Lactate functions as the final executor of DDK2 to stimulate tube formation of endothelial cells, and blockage of lactate secretion by lactate transporter (MCT) inhibitors dramatically neutralize the progression and metastasis of CRC both in vitro and in vivo. DKK2 could cooperate with lipoprotein receptor-related protein 6, which is required for glucose uptake, and activated the downstream mTOR signal pathway to accelerate lactate secretion. In addition, the expression of DKK2 is switched on via the demethylation of miR-493-5p, which allows the dissociated of miR-493-5p from the 3'-UTRs of DKK2 and initiates its stimulatory role on CRC progression in an autocrine or paracrine manner. Conclusion: DKK2 promotes tumor metastasis and angiogenesis through a novel VEGF-independent, but energy metabolism related pathway. DKK2 might be a potential anti-angiogenic target in clinical treatment for the advanced CRC patients.

Relationship between hypoxia and response to antiangiogenic therapy in metastatic colorectal cancer

Colorectal cancer remains a major public health problem worldwide. Despite the introduction of antiangiogenic drugs for the treatment of metastatic disease, a large number of issues remains unresolved. In particular, studies on predictive biomarkers of response and pathways of resistance to these agents are lacking, making it difficult to accurately select candidates for treatment. Hypoxia is the prime driving force for tumor angiogenesis and a vicious cycle between hypoxia and angiogenesis can be observed in tumors. Anti-angiogenic drugs act inhibiting tumor vasculature and, as consequence, inducing hypoxia. However, hypoxia could, in turn, induce an increase of metastatic potential of cells and a series of phenomena that could induce drug resistance. In the present review biological mechanisms of hypoxia and its relation with angiogenesis, and resistance to antiangiogenic therapy will be discussed. Moreover, data from clinical trials on antiangiogenic drugs in metastatic colorectal cancer will be reviewed, and the role of hypoxia in monitoring the response to treatment will be analysed. Combination strategies using anti-angiogenic and hypoxia inhibiting drugs are also discussed as they constitute promising field of research.

CLINICAL AND ELECTROPHYSIOLOGICAL EVALUATION AFTER INTRAVITREAL ZIV-AFLIBERCEPT FOR EXUDATIVE AGE-RELATED MACULAR DEGENERATION

Fifteen patients with exudative age-related macular degeneration were treated with intravitreal injections of ziv-aflibercept (1.25 mg). Ziv-aflibercept improved the best-corrected visual acuity, multifocal electroretinography amplitudes, and central retinal thickness from baseline to 26 weeks. No retinal toxicity on full-field electroretinography or adverse events occurred during the follow-up period.

To evaluate the 6-month safety and efficacy of ziv-aflibercept intravitreal injections for treating exudative age-related macular degeneration.

Efficacy and safety of FOLFIRI and biotherapy versus FOLFIRI alone for metastatic colorectal cancer patients: A meta-analysis

BACKGROUND

Previous randomized controlled trials (RCTs) and meta-analyses have demonstrated the useless of FOLFIRI alone for previously treated patients with metastatic colorectal cancer (mCRC). The role of FOLFIRI regimen combined with biological therapy is unknown. The purpose of this meta-analysis is to evaluate the efficacy and safety of combining biological therapy with chemotherapy in previously treated patients with mCRC.

METHODS

MEDLINE, EMBASE, Web of Science, Cochrane library, and ClinicalTrials.gov were searched. Eligible studies were RCTs that evaluated the efficacy and safety of the FOLFIRI regimen with or without biological therapy for previously treated patients with mCRC. The hazard ratio (HR) or risk ratio (RR) with 95% confidence interval was estimated. The Chi-squared and I-squared tests were used to assess the statistical heterogeneity.

RESULTS

The literature search identified 7 RCTs that met the inclusion criteria for the meta-analysis, and 3680 patients with mCRC were included. The meta-analysis showed that combined therapy was associated with a significant improved progression-free survival (PFS) (HR = 0.78, 95% CI = 0.72-0.85, P < .001), overall survival (OS) (HR = 0.84, 95% CI = 0.77-0.92, P < .001), and overall response rate (ORR) (RR = 1.70, 95% CI = 1.25-2.31, P = .001). Sensitivity analysis suggested that combined therapy versus FOLFIRI alone might increase the risk of Grade 3/4 AEs.

CONCLUSION

The addition of biological therapy to the FOLFIRI regimen improved the PFS, OS, and ORR compared with FOLFIRI alone for previously treated patients with mCRC. Long-term survival outcomes are warranted.

CCR6 promotes tumor angiogenesis via the AKT/NF-κB/VEGF pathway in colorectal cancer

Chemokines and chemokine receptors play an important role in tumorigenesis. Angiogenesis is a vital part of the occurrence, development and metastasis of cancer. CCR6 is an important factor during tumor progression; however, its function in tumor angiogenesis is not fully understood. In our study, we found that CCR6 was significantly overexpressed in colorectal cancer (CRC) tissues and predicted a poor prognosis in CRC patients. We then verified the function of CCR6 on tumor angiogenesis in vivo and in vitro. We observed that silencing CCR6 could decrease angiogenesis by inhibiting the proliferation and migration of human umbilical vein endothelial cells (HUVECs), whereas overexpression of CCR6 can promote angiogenesis. Additionally, we investigated the molecular mechanisms and demonstrated that activation of the AKT/NF-κB pathway maybe involved in CCR6-mediated tumor angiogenesis, which was able to promote the secretion of vascular endothelial growth factor A (VEGF-A). In conclusion, CCR6 facilitates tumor angiogenesis via the AKT/NF-κB/VEGF pathway in colorectal cancer. CCR6 inhibition may be a novel option for anti-vascular treatment in CRC.

The Allosteric Hemoglobin Effector ITPP Inhibits Metastatic Colon Cancer in Mice

OBJECTIVE

To test the effects of enhanced intracellular oxygen contents on the metastatic potential of colon cancer.

BACKGROUND

Colorectal cancer is the commonest gastrointestinal carcinoma. Distant metastases occur in half of patients and are responsible for most cancer-related deaths. Tumor hypoxia is central to the pathogenesis of metastases. Myo-Inositoltrispyrophosphate (ITPP), a nontoxic, antihypoxic compound, has recently shown significant benefits in experimental cancer, particularly when combined with standard chemotherapy. Whether ITPP protects from distant metastases in primary colon cancer is unknown.

METHODS

ITPP alone or combined with FOLFOX was tested in a mouse model with cecal implantation of green fluorescent protein-labeled syngeneic colorectal cancer cells. Tumor development was monitored through longitudinal magnetic resonance imaging-based morphometric analysis and survival. Established serum markers of tumor spread were measured serially and circulating tumor cells were detected via fluorescence measurements.

RESULTS

ITPP significantly reduced the occurrence of metastases as well as other indicators of tumor aggressiveness. Less circulating tumor cells along with reduction in malignant serum markers (osteopontin, Cxcl12) were noted. The ITPP benefits also affected the primary cancer site. Importantly, animals treated with ITPP had a significant survival benefit compared with respective controls, while a combination of FOLFOX with ITPP conferred the maximum benefits, including dramatic improvements in survival (mean 86 vs 188 d).

CONCLUSIONS

Restoring oxygen in metastatic colon cancer through ITPP inhibits tumor spread and markedly improves animal survival; an effect that is enhanced through the application of subsequent chemotherapy. These promising novel findings call for a clinical trial on ITPP in patients with colorectal cancer, which is under way.

Exploring the Benefit/Risk Associated with Antiangiogenic Agents for the Treatment of Non-Small Cell Lung Cancer Patients

Following the approval of bevacizumab, an antibody targeting VEGF-A, for advanced non-squamous non-small cell lung cancer (NSCLC) in 2006, intensive efforts were put into the clinical development of antiangiogenic agents for NSCLC. Currently, the other antiangiogenic agents approved for NSCLC are ramucirumab, a VEGF receptor-2 (VEGFR-2)-targeting antibody indicated for both squamous and non-squamous NSCLC in the United States, and nintedanib, an anti-VEGFR-1/2/3, platelet-derived growth factor receptor-α/β, fibroblast growth factor receptor-1/2/3 angiokinase inhibitor indicated for adenocarcinoma of the lung in the European Union. Many other antiangiogenic agents are being evaluated in phase III trials for NSCLC, including aflibercept, sunitinib, sorafenib, cediranib, and vandetanib. Although many of the same signaling pathways are targeted by these novel agents, mixed efficacy results have been observed in these trials. Moreover, safety issues have raised concerns about using antiangiogenic agents in this patient population, and fatal bleeding events have been reported. Importantly, although no biomarker has yet been validated for antiangiogenic agents in NSCLC, biomarkers that show potential include circulating levels of short VEGF-A isoforms, expression of neuropilin-1 and VEGFR-1 in tumors and plasma, genetic variants in VEGF-A and VEGFR, and tumor protein p53 mutations (with the latter having been shown to correlate with increased levels of VEGF-A transcripts). This review provides an overview of the clinical benefit and risk associated with the use of antiangiogenic agents for NSCLC, and summarizes the research to date on the identification of predictive biomarkers for antiangiogenic therapies. Clin Cancer Res; 23(5); 1137-48. ©2016 AACR.

Cell-specific biomarkers and targeted biopharmaceuticals for breast cancer treatment

Breast cancer is the second leading cause of cancer death among women, and its related treatment has been attracting significant attention over the past decades. Among the various treatments, targeted therapy has shown great promise as a precision treatment, by binding to cancer cell-specific biomarkers. So far, great achievements have been made in targeted therapy of breast cancer. In this review, we first discuss cell-specific biomarkers, which are not only useful for classification of breast cancer subtyping but also can be utilized as goals for targeted therapy. Then, the innovative and generic-targeted biopharmaceuticals for breast cancer, including monoclonal antibodies, non-antibody proteins and small molecule drugs, are reviewed. Finally, we provide our outlook on future developments of biopharmaceuticals, and provide solutions to problems in this field.

Novel pyrazolopyridine derivatives as potential angiogenesis inhibitors: Synthesis, biological evaluation and transcriptome-based mechanistic analysis

Modified purine derivatives exemplified by pyrazolopyrimidines have emerged as highly selective inhibitors of several angiogenic receptor tyrosine kinases. Herein, we designed and synthesized a new series of substituted pyrazolopyridines and explored their ability to influence crucial pro-angiogenic attributes of endothelial cells. Four of the synthesized compounds, possessing analogous substitution pattern, were found able to inhibit at low micromolar concentrations endothelial cell proliferation, migration and differentiation, constitutively or in response to Vascular Endothelial Growth Factor (VEGF) and to attenuate VEGF-induced phosphorylation of VEGF receptor-2 and downstream kinases AKT and ERK1/2. Administration of effective compounds in mice delayed the growth of syngeneic Lewis lung carcinoma transplants and reduced tumor microvessel density, without causing toxicity. Genome-wide microarray and gene ontology analyses of treated endothelial cells revealed derivative 18c as the most efficient modulator of gene expression and "mitotic cell cycle/cell division" along with "cholesterol biosynthesis" as the most significantly altered biological processes.

The coming of ramucirumab in the landscape of anti-angiogenic drugs: potential clinical and translational perspectives

INTRODUCTION

Angiogenesis plays a pivotal role in the development and progression of tumors and it represents a crucial target for therapeutic strategies. Until now, regulatory agencies approved antiangiogenic agents targeting the VEGF and multi-target agents carrying antiangiogenic and anti-proliferative effects. They often provide only a modest survival benefit and their role in clinical practice is debated. The limited efficacy may be partially explained by the complexity of the molecular background of angiogenic processes, composed of several pathways interacting with both tumor cells and the microenvironment.

AREAS COVERED

Ramucirumab is a fully human monoclonal antibody selectively binding and inhibiting the VEGF receptor 2 (VEGFR-2), a crucial molecule involved in angiogenesis. A series of Phase I-II trials conducted in a wide spectrum of malignancies reported promising antitumor activity. In 2014, data from large Phase III clinical trials in gastrointestinal, lung and breast malignancies were released.

EXPERT OPINION

Considering the evidences of efficacy emerging from the available Phase III trials, the antiangiogenic approach emerged as a promising strategy particularly for the treatment of gastric cancer. Nevertheless, the identification and validation of potentially predictive biomarkers are necessary to improve the selection of patients and the globally awaited clinical benefit.

Aflibercept a new target therapy in cancer treatment: a review

Angiogenesis is the process through which new blood vessels are formed from pre-existing vessels and is essential for the growth of all solid tumors. Vascular endothelial growth factor (VEGF) is a regulator of angiogenesis, which is crucial for tumor growth and metastasis. Its inhibition with antiangiogenic drugs is thought to improve delivery of chemotherapy through vascular normalization and disruption of tumor vasculature. Aflibercept is a recombinant fusion protein of the VEGF receptor (VEGFR)1 and VEGFR2 extracellular domains that binds to VEGF-A, VEGF-B, placental growth factor (PlGF) 1 and 2. Aflibercept has demonstrated preclinical efficacy in different tumor types and exerts its antiangiogenic effects through regression of tumor vasculature, remolding of vasculature, and inhibition of new tumor vessel growth. This review examines the effects of aflibercept on tumor vasculature and on different types of solid tumors, and explores the preclinical and clinical benefits of inclusion aflibercept into anticancer treatment strategies.

Fc-fusion proteins and FcRn: structural insights for longer-lasting and more effective therapeutics

Nearly 350 IgG-based therapeutics are approved for clinical use or are under development for many diseases lacking adequate treatment options. These include molecularly engineered biologicals comprising the IgG Fc-domain fused to various effector molecules (so-called Fc-fusion proteins) that confer the advantages of IgG, including binding to the neonatal Fc receptor (FcRn) to facilitate in vivo stability, and the therapeutic benefit of the specific effector functions. Advances in IgG structure-function relationships and an understanding of FcRn biology have provided therapeutic opportunities for previously unapproachable diseases. This article discusses approved Fc-fusion therapeutics, novel Fc-fusion proteins and FcRn-dependent delivery approaches in development, and how engineering of the FcRn-Fc interaction can generate longer-lasting and more effective therapeutics.

New therapeutic targets for cancer bone metastasis

Bone metastases are dejected consequences of many types of tumors including breast, prostate, lung, kidney, and thyroid cancers. This complicated process begins with the successful tumor cell epithelial-mesenchymal transition, escape from the original site, and penetration into the circulation. The homing of tumor cells to the bone depends on both tumor-intrinsic traits and various molecules supplied by the bone metastatic niche. The colonization and growth of cancer cells in the osseous environment, which awaken their dormancy to form micro- and macro-metastasis, involve an intricate interaction between the circulating tumor cells and local bone cells including osteoclasts, osteoblasts, adipocytes, and macrophages. We discuss the most recent advances in the identification of new molecules and novel mechanisms during each step of bone metastasis that may serve as promising therapeutic targets.

Renal effects of targeted anticancer therapies

The use of novel targeted anticancer agents has led to overall improvement in the prognosis of many patients affected by various malignancies, but has also been associated with an increased risk of poorly characterized toxic effects to different organs, including the kidneys. The high prevalence of kidney impairment in the general population complicates the issue further. Nephrologists most frequently work with patients with cancer when they are asked to investigate kidney function to assess the need for dose adjustments in anticancer therapy. A thorough knowledge of the renal safety profile of novel life-prolonging anticancer therapies, specific features of their metabolism, and pharmacokinetic and pharmacodynamic properties (under normal circumstances as well as in the setting of renal replacement therapy) is, therefore, necessary to preserve kidney function as far as possible and to ensure optimum treatment. In this Review we summarize the present knowledge of renal toxic effects from novel targeted anticancer agents and discuss whether the management of patients' treatment needs to be modified. We also advocate the development of a new onconephrology subspeciality.

The IGF-Trap: Novel Inhibitor of Carcinoma Growth and Metastasis

The IGFI receptor promotes malignant progression and has been recognized as a target for cancer therapy. Clinical trials with anti-IGFIR antibodies provided evidence of therapeutic efficacy but exposed limitations due in part to effects on, and the compensatory function of, the insulin receptor system. Here, we report on the production, characterization, and biologic activity of a novel, IGF-targeting protein (the IGF-Trap) comprising a soluble form of hIGFIR and the Fc portion of hIgG1. The IGF-Trap has a high affinity for hIGFI and hIGFII but low affinity for insulin, as revealed by surface plasmon resonance. It efficiently blocked IGFIR signaling in several carcinoma cell types and inhibited tumor cell proliferation, migration, and invasion in vitro. In vivo, the IGF-Trap showed favorable pharmacokinetic properties and could suppress the growth of established breast carcinoma tumors when administered therapeutically into tumor-bearing mice, improving disease-free survival. Moreover, IGF-Trap treatment markedly reduced experimental liver metastasis of colon and lung carcinoma cells, increasing tumor cell apoptosis and reducing angiogenesis. Finally, when compared with an anti-IGFIR antibody or IGF-binding protein-1 that were used at similar or higher concentrations, the IGF-Trap showed superior therapeutic efficacy to both inhibitors. Taken together, we have developed a targeted therapeutic molecule with highly potent anticancer effects that could address limitations of current IGFIR-targeting agents.

Anti-VEGF Cancer Therapy in Nephrology Practice

Expanded clinical experience with the antivascular endothelial growth factor (VEGF) agents has come with increasing recognition of their renal adverse effects. Although renal histology is rarely sought in antiangiogenic-treated cancer patients, kidney damage related to anti-VEGF is now established. Its manifestations include hypertension, proteinuria, and mainly glomerular thrombotic microangiopathy. Then, in nephrology practice, should we continue to perform kidney biopsy, and what should be done with the anti-VEGF agents in case of renal toxicity?

Personalizing medicine for metastatic colorectal cancer: current developments

Metastatic colorectal cancer (mCRC) is still one of the tumor types with the highest incidence and mortality. In 2012, colorectal cancer was the second most prevalence cancer among males (9%) and the third among females (8%). In this disease, early diagnosis is important to improve treatment outcomes. However, at the time of diagnosis, about one quarter of patients already have metastases, and overall survival of these patients at 5-years survival is very low. Because of these poor statistics, the development of new drugs against specific targets, including the pathway of angiogenesis, has witnessed a remarkable increase. So, targets therapies through epidermal growth factor and its receptor and also KRAS pathways modulation acquired a main role whether in association with standard chemotherapy and radiotherapy. With the current knowledge in the field of molecular biology, including genetic mutations and polymorphisms, we know better why patients respond so differently to the same treatments. So, in the future we can develop increasingly personalized treatments to the patient and not the disease. This review aims to summarize some molecular pathways and their relation to tumor growth, as well as novel targeted developing drugs and recently approved for mCRC.

Targeted therapy in advanced metastatic colorectal cancer: Current concepts and perspectives

The introduction of new cytotoxic substances as well as agents that target vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) signaling has improved clinical outcome of patients with metastatic colorectal cancer (mCRC). In this review we summarize the most relevant clinical data on VEGF and EGFR targeting regimens in mCRC. The effects of available treatment strategies for mCRC are often temporary, with resistance and disease progression developing in most patients. Thus, new treatment strategies are urgently needed. Some GI peptides including gastrin and gastrin releasing peptide, certain growth factors such as insulin-like growth factor-I and II and neuropeptides such as growth hormone releasing hormone (GHRH) are implicated in the growth of CRC. Experimental investigations in CRC with antagonistic analogs of bombesin/gastrin-releasing peptide, GHRH, and with cytotoxic peptides that can be targeted to peptide receptors on tumors, are summarized in the second part of the review.

Sequencing of antiangiogenic agents in the treatment of metastatic colorectal cancer

Significant advances have been made with respect to our understanding of the critical role of agents targeting angiogenic pathways in the treatment of metastatic colorectal cancer (mCRC). The approval of 3 agents that target angiogenic signaling, bevacizumab, ziv-aflibercept, and regorafenib, provides strong evidence that angiogenesis is an important process in mCRC. The addition of bevacizumab to combination chemotherapy in the first- and second-line treatment of mCRC has resulted in meaningful improvement in overall and progression-free survival. The standard of care for mCRC has evolved to incorporate cytotoxic chemotherapy as the backbone regimens (eg, FOLFOX [folinic acid, 5-fluorouracil, and oxaliplatin], FOLFIRI [folinic acid, 5-fluorouracil, and irinotecan]) with or without bevacizumab, and epidermal growth factor receptor-targeted therapies (eg, cetuximab, panitumumab) in the setting of wild-type KRAS. The development of ziv-aflibercept in combination with FOLFIRI has improved clinical efficacy in the second-line treatment of mCRC. Regorafenib, a small-molecule multikinase inhibitor, has recently been approved by the US Food and Drug Administration as single-agent therapy in the treatment of refractory and progressive mCRC. Each of these agents has been integrated into an evidence-based-albeit, still evolving-treatment continuum for initial treatment, treatment after first progression, and treatment after second progression. However, the most effective strategy for the use of these agents, and others in development remains unclear. This review provides an overview of the current clinical evidence for the use of antiangiogenic agents targeting in the treatment of mCRC.

New treatment options for lung adenocarcinoma--in view of molecular background

Lung cancer is the leading cause of cancer related mortality all over the world, and a number of developments have indicated future clinical benefit recently. The development of molecular pathology methods has become increasingly important in the prediction of chemotherapy sensitivity and mutation analysis to identify driver mutations as important targets of new therapeutic agents. The most significant changes in the treatment of NSCLC revealed in new pathologic classification and in the introduction of molecularly targeted therapies, which include monoclonal antibodies and small molecule tyrosine kinase inhibitors. The side effects of these agents are generally better tolerated than those of conventional chemotherapy and show higher efficacy. The most important factor follows: histology subtypes, gene mutation status, patients' selection, drug toxicities and occurence of drug resistance. In the advanced disease, the hope of cure is less than 3%, but improvements in survival have been clearly achieved. Some years ago the median lung cancer survival rate was 10-12 months, now in case of available specific molecular targets, a significant increase in median survival rates to 24-36 months has been achieved. These agents give an opportunity to provide a new standard of care. Therefore testing EGFR mutations and ALK rearrangements in patients with advanced lung adenocarcinoma should be incorporated into routine clinical practice. This review focuses on the rationale for targeted agents and new treatment possibilities in case of advanced lung adenocarcinoma.

Ziv-aflibercept: A novel angiogenesis inhibitor for the treatment of metastatic colorectal cancer

Purpose

The pharmacology, pharmacokinetics, clinical efficacy, safety, and administration of ziv-aflibercept in combination therapy for metastatic colorectal cancer (mCRC) are reviewed.

Summary

Ziv-aflibercept (Zaltrap, Regeneron Pharmaceuticals and sanofi-aventis) is a novel recombinant fusion protein that targets the angiogenesis signaling pathway of tumor cells by blocking vascular endothelial growth factor (VEGF) receptors that play a key role in tumor growth and metastasis; it is a more potent VEGF blocker than bevacizumab. Ziv-aflibercept is approved by the Food and Drug Administration for use in combination with fluorouracil, irinotecan, and leucovorin (the FOLFIRI regimen) for second-line treatment of patients with mCRC who have disease progression during first-line oxaliplatin-based chemotherapy. A Phase III trial demonstrated that relative to FOLFIRI therapy alone, the use of ziv-aflibercept was associated with significantly improved patient response, overall survival, and progression-free survival in patients with good performance status at baseline, including some who had received prior bevacizumab therapy. The most common grade 3 or 4 adverse effects associated with ziv-aflibercept use in clinical studies were neutropenia, hypertension, and diarrhea; the U.S. product labeling warns of potential hemorrhage and other treatment-related risks.

Conclusion

Current clinical data are insufficient to directly compare ziv-aflibercept and bevacizumab when used with standard combination chemotherapy as first- or second-line regimens for mCRC. The role of ziv-aflibercept is currently limited to the second-line setting in combination with irinotecan-based regimens in mCRC patients who have not received irinotecan previously. The role of ziv-aflibercept in chemotherapy for other tumor types is yet to be determined.

Novel therapeutic approaches for the treatment of castration-resistant prostate cancer

Prostate cancer is a leading cause of cancer death in men in developed countries. Once the tumor has achieved a castration-refractory metastatic stage, treatment options are limited with the average survival of patients ranging from two to three years only. Recently, new drugs for treatment of castration-resistant prostate cancer (CRPC) have been approved, and others are in an advanced stage of clinical testing. In this review we provide an overview of the new therapeutic agents that arrived in the clinical praxis or are tested in clinical studies and their mode of action including hormone synthesis inhibitors, new androgen receptor blockers, bone targeting and antiangiogenic agents, endothelin receptor antagonists, growth factor inhibitors, novel radiotherapeutics and taxanes, and immunotherapeutic approaches. Results and limitations from clinical studies as well as future needs for improvement of CRPC treatments are critically discussed.

Antiangiogenesis therapy in second line metastatic colorectal cancer: similar but different

Recent updates in the second-line treatment of patients with metastatic colorectal cancer (mCRC) have indicated the benefit of adding aflibercept (plus FOLFIRI) after an oxaliplatin-containing regimen (with or without bevacizumab) or a bevacizumab-containing regimen after progression on a different bevacizumab-containing regimen. This has led some oncologists to compare the trials and equate the drugs, with the assumption that they confer equal efficacy, but the background of this must be adequately assessed before reaching this conclusion. In fact, the publication of these trial results has left oncologists with much to consider for their mCRC patients who will eventually progress on a first-line chemotherapy/bevacizumab regimen. The author comments on this issue and emphasizes the need for additional research into antiangiogenic biomarkers to identify patients who are likely to respond to one drug more than another.

Molecularly targeted drugs for metastatic colorectal cancer

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

Aflibercept versus placebo in combination with fluorouracil, leucovorin and irinotecan in the treatment of previously treated metastatic colorectal cancer: prespecified subgroup analyses from the VELOUR trial

PURPOSE

The antiangiogenic agent aflibercept (ziv-aflibercept in the United States) in combination with 5-fluorouracil, leucovorin and irinotecan (FOLFIRI) significantly improved survival in a phase III study of patients with metastatic colorectal cancer (mCRC) previously treated with an oxaliplatin-based regimen. In the present analysis, outcomes were evaluated in prespecified subgroups to assess the consistency of the treatment effect.

METHODS

Patients were randomised to receive FOLFIRI plus aflibercept or placebo every 2weeks until disease progression or unacceptable toxicity occurred. Efficacy and safety outcomes were analysed with respect to demographic and baseline characteristics, and stratification factors (prior bevacizumab treatment and Eastern Cooperative Oncology Group performance status).

RESULTS

Median overall survival (OS, months [95.34% confidence interval (CI)]) for aflibercept versus placebo was 12.5 (10.8-15.5) versus 11.7 (9.8-13.8) in patients with prior bevacizumab treatment and 13.9 (12.7-15.6) versus 12.4 (11.2-13.5) in patients with no prior bevacizumab treatment. The p value for interaction was 0.5668, indicating there was no heterogeneity in these subgroups. For OS and progression-free survival (PFS), there was a significantly greater benefit (at the 2-sided 10% level) of treatment for patients with liver only metastases versus patients with no liver metastases/liver metastases with other organ involvement (p value for interaction: 0.0899 [OS]; 0.0076 [PFS]). There was no evidence of heterogeneity in treatment effect in any of the other subgroups examined.

CONCLUSIONS

The benefits of aflibercept in combination with FOLFIRI in patients with mCRC previously treated with oxaliplatin were maintained across the specified patient subgroups, including in patients with or without prior bevacizumab treatment.

From bevacizumab to tasquinimod: angiogenesis as a therapeutic target in prostate cancer

It was first posited in the 1970s that angiogenesis may prove to be a useful target for anticancer therapies. Since then, a number of agents have been developed and tested across a range of tumor types; however, to date, there have unfortunately been more failures than successes. Prostate cancer (PCa) is no exception in this regard, and despite a strong preclinical rationale for targeting angiogenesis in men with PCa, there has yet to be an antiangiogenic therapy proven to prolong survival in this group of patients. Drugs have been developed to target a host of angiogenesis mediators. These include vascular endothelial growth factor (VEGF), the VEGF receptors, antiangiogenic factors (e.g., thrombospondin-1), and downstream mediators of angiogenesis (e.g., hypoxia-inducible factor-1α and MET). At present, there are 2 drugs being tested in the phase III setting for men with PCa: cabozantinib and tasquinimod. Cabozantinib, a dual VEGF receptor-2/MET inhibitor, has shown dramatic beneficial effects on radiographically evident bone metastases and pain in the phase II setting. There are currently 2 large phase III trials underway to further investigate cabozantinib's role in treating men with PCa. Both trials randomize subjects to cabozantinib versus mitoxantrone: one is designed to evaluate overall survival, and the other, pain response durability. The other drug, tasquinimod, has a somewhat poorly understood mechanism of action. It is thought to exert an antiangiogenic effect through the inhibition of myeloid-derived suppressor cells, key to the support of an angiogenic environment, and down-regulation of hypoxia-inducible factor-1α. A phase II trial randomizing men to tasquinimod versus placebo revealed a median progression-free survival advantage in the experimental arm (7.6 vs. 3.3 months with placebo; P = 0.0042). Based on these encouraging phase II results, a randomized, double-blind, placebo-controlled trial in men with metastatic castration-resistant PCa was launched. That trial is powered for a primary endpoint of progression-free survival and is expected to enroll 1200 men.

Targeted therapies in non-small cell lung carcinoma: what have we achieved so far?

The search for innovative therapeutic agents in non-small cell lung cancer (NSCLC) has witnessed a swift evolution. The number of targeted drugs that can improve patient outcomes with an acceptable safety profile is steadily increasing. In this review, we highlight current drugs that have already been approved or are under evaluation for the treatment of patients with NSCLC, either in monotherapy or combined therapy for both the first- and second-line settings. Experience with drugs targeting the vascular endothelial growth factor and its receptor, as well as the epidermal growth factor receptor is summarized. Moreover, we provide an overview of more novel targets in NSCLC and initial experience with the respective therapeutic agents.

Anti-VEGF agents in metastatic colorectal cancer (mCRC): are they all alike?

Bevacizumab is a monoclonal antibody that binds and neutralizes vascular endothelial growth factor (VEGF)-A, a key player in the angiogenesis pathway. Despite benefits of bevacizumab in cancer therapy, it is clear that the VEGF pathway is complex, involving multiple isoforms, receptors, and alternative ligands such as VEGF-B, and placental growth factor, which could enable escape from VEGF-A-targeted angiogenesis inhibition. Recently developed therapies have targeted other ligands in the VEGF pathway (eg, aflibercept, known as ziv-aflibercept in the United States), VEGF receptors (eg, ramucirumab), and their tyrosine kinase signaling (ie, tyrosine kinase inhibitors). The goal of the current review was to identify comparative preclinical data for the currently available VEGF-targeted therapies. Sources were compiled using PubMed searches (2007 to 2012), using search terms including, but not limited to: “bevacizumab,” “aflibercept,” “ramucirumab,” and “IMC-18F1.” Two preclinical studies were identified that compared bevacizumab and the newer agent, aflibercept. These studies identified some important differences in binding and pharmacodynamic activity, although the potential clinical relevance of these findings is not known. Newer antiangiogenesis therapies should help further expand treatment options for colorectal and other cancers. Comparative preclinical data on these agents is currently lacking.

The evolving role of VEGF-targeted therapies in the treatment of metastatic colorectal cancer

Therapies that target angiogenesis and the VEGF pathway are a component of treatment for patients with metastatic colorectal cancer (mCRC). Bevacizumab is a humanized monoclonal antibody that binds to VEGFA. Chemotherapy plus bevacizumab has led to improved outcomes for mCRC patients. Despite these benefits, progressive disease invariably ensues. Multiple members of the VEGF family can potentially contribute to tumor angiogenesis and/or evasion of antiangiogenic therapy if one pathway should be inhibited. Aflibercept, a new biological agent, is a multiple angiogenic factor trap that prevents not only VEGFA, but also VEGFB and PlGF from activating their native receptors. Key clinical data for bevacizumab and aflibercept for treatment of mCRC, clinical evidence for use of these agents beyond progression, and the search for angiogenic biomarkers to better define patients most likely to benefit from these interventions will be reviewed.

Targeted approach to metastatic colorectal cancer: what comes beyond epidermal growth factor receptor antibodies and bevacizumab?

The prognosis of patients with cancer remains poor in spite of the advances obtained in recent years with new therapeutic agents, new approaches in surgical procedures and new diagnostic methods. The discovery of a plethora of cellular targets and the rational generation of selective targeting agents has opened an era of new opportunities and extraordinary challenges. The specificity of these agents renders them capable of specifically targeting the inherent abnormalities of cancer cells, potentially resulting in less toxicity than traditional nonselective cytotoxics. Among the many new types of rationally designed agents are therapeutics targeting various strategic facets of growth signal transduction, malignant angiogenesis, survival, metastasis and cell-cycle regulation. The evaluation of these agents is likely to require some changes from the traditional drug development paradigms to realize their full potential. Inhibition of the epidermal growth factor receptor and the vascular endothelial growth factor have provided proof of principle that disruption of signal cascades in patients with colorectal cancer has therapeutic potential. This experience has also taught us that resistance to such rationally developed targeted therapeutic strategies is common. In this article, we review the role of signal transduction in colorectal cancer, introduce promising molecular targets, and outline therapeutic approaches under development.

Emerging VEGF-receptor inhibitors for colorectal cancer

INTRODUCTION

Targeted agents have dramatically improved and enriched the therapeutical choices for patients with metastatic colorectal cancer (mCRC). By better understanding the role of the angiogenic pathway in colorectal cancer (CRC), new therapies have been developed. Bevacizumab, the first anti-angiogenetic agent approved for the treatment of mCRC provide a proof of concept since it has improved the progression-free survival and overall survival when combined with cytotoxic chemotherapy.

AREAS COVERED

This review is focused on the most recent findings on the VEGF signaling pathway and new therapeutic drugs explored in clinical trials.

EXPERT OPINION

Despite the advantage offered by bevacizumab, the median overall survival of mCRC patient exceeds 21 months; thus, investigational efforts are needed. Several antiangiogenic agents for the treatment of mCRC are being tested in preclinical and clinical Phase I/II trials. Unfortunately a discrete number of Phase III trials produced negative results. Recently aflibercept and regorafenib, two new antiangiogenic drugs, have been approved as the new-targeted agents for the treatment of mCRC, according to the positive findings from the VELOUR and the CORRECT studies. In order to maximize clinical impact it will be important to validate predictive biomarkers and best combination treatments to offer for mCRC patients; further research and intense investigation is still required.

Antiangiogenesis therapy in the treatment of metastatic colorectal cancer

The process of new blood vessel formation, or angiogenesis, has become an important target for therapeutic intervention in many cancers, including metastatic colorectal cancer (mCRC). The growth and metastasis of primary tumors is dependent upon their ability to acquire and maintain an adequate blood supply; however, angiogenesis in tumors is an irregular process leading to chaotic and hyperpermeable vessels that may result in increased intratumoral pressure and poor exchange of macromolecules and oxygen. It has been hypothesized that inhibition of angiogenesis in tumors can both impair the formation of new tumor blood vessels and possibly 'normalize' the existing tumor vasculature, causing a more efficient delivery of cytotoxic chemotherapies (CTs). Over the last decade, therapies that target vascular endothelial growth factor (VEGF) have become a component of treatment for several cancers. In particular, the combination of bevacizumab with established chemotherapeutic regimens for mCRC has been shown to improve overall and progression-free survival, as well as response rates, over CT alone. Agents that target various members of the VEGF family, as well as signaling by the VEGF receptors and their tyrosine kinase components, are currently under development and evaluation in clinical trials. Integration of these new therapies into the treatment of mCRC will ultimately increase the available therapeutic options for patients. Still, many challenges remain, including identifying and validating relevant biomarkers to guide the optimal use of antiangiogenesis agents.

Targeted therapy for metastatic colorectal cancer: role of aflibercept

Worldwide, colorectal cancer (CRC) is the third most commonly diagnosed cancer in male individuals and the second most commonly diagnosed cancer in female individuals. Survival outcomes are less than optimal for patients with metastatic disease, with a 5-year survival in the 5% to 8% range. The development of new chemotherapeutic agents and effective combination regimens for metastatic colorectal cancer (mCRC) has increased median overall survival (OS) to the 24- to 28-month range. Because of the recognition that vascular endothelial growth factors (VEGFs) and their receptors are primary regulators of physiologic and pathologic angiogenesis and lymphangiogenesis, leading to neovascularization and tumor growth, the targeting of the angiogenic pathway has become a focus of key therapeutic strategies in mCRC. Therapeutic regimens that include bevacizumab, an inhibitor of VEGF-A, in combination with cytotoxic chemotherapy, have resulted in improved response rate (RR) and survival in mCRC. However, the effects of VEGF-A inhibition are often temporary, with resistance and disease progression developing in most patients. Proposed models include intrinsic and adaptive resistance, mediated by factors other than VEGF-A. Aflibercept (known as ziv-aflibercept in the United States; Zaltrap®, Regeneron Pharmaceuticals; sanofi-aventis), a novel recombinant fusion protein, is an angiogenic factor trap that blocks the binding of VEGF-A, VEGF-B, and placental growth factor. Phase I/II clinical trials have demonstrated effective activity in mCRC, with acceptable safety and tolerability. A recent phase III randomized double-blind trial in patients previously treated with oxaliplatin reported significant improvement in OS, progression-free survival (PFS), and RR with aflibercept compared with placebo when administered in combination with irinotecan and fluorouracil. Adverse events were consistent with anti-VEGF therapy. Thus aflibercept represents a potential new treatment option for patients with mCRC.

Assessing the in vivo efficacy of biologic antiangiogenic therapies

PURPOSE

To review key clinical issues underlying the assessment of in vivo efficacy when using antiangiogenic therapies for cancer treatment.

METHODS

Literature relevant to use of antiangiogenic therapies in cancer was reviewed, with particular emphasis on the assessment of in vivo efficacy of these agents, as well as additional angiogenic factors that could play a role in escape from angiogenesis inhibition.

RESULTS

In order to grow and metastasize, tumors need to continually acquire new blood supplies; therefore, therapeutic inhibition of angiogenesis has become a component of anticancer treatment for many tumor types. Bevacizumab, a humanized monoclonal antibody directed at vascular endothelial growth factor A (VEGF-A), has shown activity in combination with chemotherapy in metastatic colorectal cancer. Nevertheless, the use of antiangiogenic therapies remains suboptimal; specifically, optimal dose, duration of therapy, and combination of agents remain unknown. Also, at present, it is not possible to determine which patients are most likely to respond to a given form of antiangiogenic therapy. There has been increased recognition of alternative pathways possibly associated with disease progression in patients undergoing antiangiogenic therapy targeted at VEGF-A. Multiligand-targeted antiangiogenic therapies, such as ziv-aflibercept (formerly known as aflibercept, VEGF Trap), are currently undergoing clinical evaluation. Ziv-aflibercept forms monomeric complexes with VEGF-A, VEGF-B, and PlGF, which have a long half-life, allowing optimization of ziv-aflibercept doses and angiogenic blockage.

CONCLUSIONS

Although antiangiogenic therapies have increased treatment options for cancer patients, their use is limited by a lack of established and standardized methodology to evaluate their efficacy in vivo. Circulating endothelial cells, hypertension, and several molecular and imaging-based markers have potential for use as biomarkers in these patients and may better define appropriate patient populations.

Addition of Aflibercept to Fluorouracil, Leucovorin, and Irinotecan Improves Survival in a Phase III Randomized Trial in Patients With Metastatic Colorectal Cancer Previously Treated With an Oxaliplatin-Based Regimen

Purpose

Treatment for metastatic colorectal cancer (mCRC) commonly involves a fluoropyrimidine-based chemotherapy regimen such as infusional fluorouracil, leucovorin, and irinotecan (FOLFIRI) or fluorouracil, leucovorin, and oxaliplatin, often combined with bevacizumab or an epidermal growth factor receptor monoclonal antibody. We studied the effect of adding the novel antiangiogenic agent aflibercept (also known as ziv-aflibercept in the United States) to FOLFIRI in patients with mCRC previously treated with oxaliplatin, including patients who received prior bevacizumab.

Patients and Methods

Patients were randomly assigned to receive aflibercept (4 mg/kg intravenously; 612 patients) or placebo (614 patients) every 2 weeks in combination with FOLFIRI. Treatment was administered until disease progression or unacceptable toxicity. The primary end point was overall survival.

Results

Adding aflibercept to FOLFIRI significantly improved overall survival relative to placebo plus FOLFIRI (hazard ratio [HR], 0.817; 95.34% CI, 0.713 to 0.937; P = .0032) with median survival times of 13.50 versus 12.06 months, respectively. Aflibercept also significantly improved progression-free survival (PFS; HR, 0.758; 95% CI, 0.661 to 0.869; P < .0001), with median PFS times of 6.90 versus 4.67 months, respectively. The effects on overall survival and PFS exhibited a consistent trend across prespecified subgroup analyses, including bevacizumab pretreated patients. Response rate was 19.8% (95% CI, 16.4% to 23.2%) with aflibercept plus FOLFIRI compared with 11.1% (95% CI, 8.5% to 13.8%) with placebo plus FOLFIRI (P = .0001). Adverse effects reported with aflibercept combined with FOLFIRI included the characteristic anti–vascular endothelial growth factor effects and also reflected an increased incidence of some chemotherapy-related toxicities.

Conclusion

Aflibercept in combination with FOLFIRI conferred a statistically significant survival benefit over FOLFIRI combined with placebo in patients with mCRC previously treated with oxaliplatin.

Angiogenesis-related agents in esophageal cancer

INTRODUCTION

Esophageal cancer is an aggressive disease with poor prognosis. The majority of the patients are diagnosed at an advanced stage and many with early stage disease will develop recurrent disease.

AREAS COVERED

Angiogenesis is essential to the progress and aggressiveness of solid malignancies. Success of anti-angiogenic therapy in colorectal, lung and breast cancers is a proof of principle. Thus far, evidence for benefit from anti-angiogenic therapy in esophageal cancer is lacking. Several Phase II trials with different agents have provided mixed results and the only Phase III trial in the esophageal and gastric cancer failed to show that these agents improve overall survival (OS). However, lack of observed benefit could be due to the challenges specific to the management of esophageal cancers as well as issues with the design of clinical trials for anti-angiogenic therapy.

EXPERT OPINION

An understanding of the biology of the esophageal cancer and its management is essential to the development of anti-angiogenic therapy in this disease. This article reviews the management of esophageal cancer and elaborates on the challenges in the development of anti-angiogenic therapy in esophageal cancer. At the end, strategies are proposed for successful development of anti-angiogenic therapy in esophageal cancer.

Overcoming resistance to antiangiogenic therapies

The concept of targeting new blood vessel formation, or angiogenesis, in tumors is an important advancement in cancer therapy, resulting, in part, from the development of such biologic agents as bevacizumab, a monoclonal antibody directed against vascular endothelial growth factor (VEGF)-A. The rationale for antiangiogenic therapy is based on the hypothesis that if tumors are limited in their capacity to obtain a new blood supply, so too is their capacity for growth and metastasis. Additional evidence suggests that pruning and/or "normalization" of irregular tumor vasculature and reduction of hypoxia may facilitate greater access of cytotoxic chemotherapy (CT) to the tumor. Indeed, for metastatic colorectal cancer, bevacizumab in combination with established CT regimens has efficacy superior to that of CT alone. Despite ~2-month longer progression-free and overall survival times than with CT alone, patients still progress, possibly because of alternative angiogenic "escape" pathways that emerge independent of VEGF-A, or are driven by hypoxic stress on the tumor. Other VEGF family members may contribute to resistance, and many factors that contribute to the regulation of tumor angiogenesis function as part of a complex network, existing in different concentrations and spatiotemporal gradients and producing a wide range of biologic responses. Integrating these concepts into the design and evaluation of new antiangiogenic therapies may help overcome resistance mechanisms and allow for greater efficacy over longer treatment periods.