Ramucirumab (IMC-1121B): a novel attack on angiogenesis

Phage display for discovery of anticancer antibodies

Antibodies and antibody-based immunotherapeutics are the mainstays of cancer immunotherapy. Expanding the repertoire of cancer-specific and cancer-associated epitopes targetable with antibodies represents an important area of research. Phage display is a powerful approach allowing the use of diverse antibody libraries to be screened for binding to a wide range of targets. In this review, we summarize the basics of phage display technology and highlight the advances in anticancer antibody identification and modification via phage display platform. Finally, we describe phage display-derived anticancer monoclonal antibodies that have been approved to date or are in clinical development.

Ramucirumab in second‑line advanced colorectal cancer therapy: A study on therapeutic outcomes and hepatic sinusoidal platelet aggregation

The present study investigated the role of ramucirumab (RAM) in treating liver metastases (LMs) as a second-line or salvage treatment in patients with advanced CRC. Of the 36 patients, 21 (58%) received RAM plus folinic acid, fluorouracil and irinotecan (FOLFIRI) as second-line treatment, whereas 15 (42%) received it in a salvage setting. The median overall survival time was 23 months [95% confidence interval (CI), 12-34 months] for those in the second-line treatment group and 8 months (95% CI, 5-19 months) for those in the salvage treatment group. Of the 36 patients, 14 (39%) underwent surgical resection of LMs during chemotherapy. A total of 6 patients underwent surgical resection for LMs for the first time during second-line RAM plus FOLFIRI (RAM-LM); of the remaining 8 patients, 6 underwent resection of LMs during first-line bevacizumab (BEV)-based chemotherapy (BEV-LM). Immunohistochemical analysis of CD42b showed that the platelet aggregation score (CD42b score), which ranges from 0 (absence of deposition) to 3 (presence of linear deposition), tended to decrease with the increasing duration of treatment with both RAM and BEV. Although there was no significant difference in the mean duration of anti-VEGF antibody treatment between the BEV-LM and RAM-LM groups, the median CD42b score was higher in the RAM-LM group (median CD42b score, 3; range, 0-3) compared with that in the BEV-LM group (median CD42b score, 1; range, 0-3; P=0.01), suggesting that RAM induces a different degree of platelet aggregation in liver sinusoids compared to BEV.

Emerging Therapeutic Targets and Future Directions in Advanced Gastric Cancer: A Comprehensive Review

Metastatic gastric cancer (GC) still represents a critical clinical challenge, with limited treatment options and a poor prognosis. Most patients are diagnosed at advanced stages, limiting the chances of surgery and cure. The identification of molecular targets and the possibility of combining immune checkpoint inhibitors with chemotherapy have recently reshaped the therapeutic landscape of metastatic gastric cancer. The new classification of gastric cancer, mainly based on immunologic and molecular criteria such as programmed cell death 1 (PD-1), microsatellite instability (MSI), and human epidermal growth factor receptor 2 (HER2), has made it possible to identify and differentiate patients who may benefit from immunotherapy, targeted therapy, or chemotherapy alone. All relevant and available molecular and immunological targets in clinical practice for the systemic treatment of this disease are presented. Particular attention is given to possible future approaches, including circulating tumor DNA (ctDNA) for therapeutic monitoring, new targeting agents against molecular pathways such as fibroblast growth factor receptor (FGFR) and MET, chimeric antigen receptor (CAR)-T cells, and cancer vaccines. This review aims to provide a comprehensive understanding of current targets in advanced gastric cancer and to offer valuable insights into future directions of research and clinical practice in this challenging disease.

Clinical progress of anti-angiogenic targeted therapy and combination therapy for gastric cancer

The incidence of gastric cancer is increasing year by year. Most gastric cancers are already in the advanced stage with poor prognosis when diagnosed, which means the current treatment is not satisfactory. Angiogenesis is an important link in the occurrence and development of tumors, and there are multiple anti-angiogenesis targeted therapies. To comprehensively evaluate the efficacy and safety of anti-angiogenic targeted drugs alone and in combination against gastric cancer, we systematically searched and sorted out relevant literature. In this review, we summarized the efficacy and safety of Ramucirumab, Bevacizumab, Apatinib, Fruquintinib, Sorafenib, Sunitinib, Pazopanib on gastric cancer when used alone or in combination based on prospective clinical trials reported in the literature, and sorted response biomarkers. We also summarized the challenges faced by anti-angiogenesis therapy for gastric cancer and available solutions. Finally, the characteristics of the current clinical research are summarized and suggestions and prospects are raised. This review will serve as a good reference for the clinical research of anti-angiogenic targeted drugs in the treatment of gastric cancer.

In silico studies of a novel scaffold of benzoxazole derivatives as anticancer agents by 3D-QSAR, molecular docking and molecular dynamics simulations

The vascular endothelial growth factor receptor-2 kinases (VEGFR-2) expressed on tumor cells and vessels are attractive targets for cancer treatment. Potent inhibitors for the VEGFR-2 receptor are novel strategies to develop anti-cancer drugs. In this work, template ligand-based 3D-QSAR studies were performed on a series of benzoxazole derivatives toward different cell lines (HepG2, HCT-116 and MCF-7). Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) techniques were used to generate 3D-QSAR models. Good predictability was derived for the optimal CoMFA models (HepG2: R_cv² = 0.509, R_pred² = 0.5128; HCT-116: R_cv² = 0.574, R_pred² = 0.5597; MCF-7: R_cv² = 0.568, R_pred² = 0.5057) and CoMSIA models (HepG2: R_cv² = 0.711, R_pred² = 0.6198; HCT-116: R_cv² = 0.531, R_pred² = 0.5804; MCF-7: R_cv² = 0.669, R_pred² = 0.6577). In addition, the contour maps derived from CoMFA and CoMSIA models were also generated to illustrate the relationship between different fields and the inhibitory activities. Moreover, molecular docking and molecular dynamics (MD) simulations were also conducted to understand the binding modes and the potential interactions between the receptor and the inhibitors. Some key residues (Leu35, Val43, Lys63, Leu84, Gly117, Leu180 and Asp191) were pointed out for stabilizing the inhibitors in the binding pocket. The binding free energies for the inhibitors agreed well with the experimental inhibitory activity and indicated that steric, electrostatic and hydrogen bond interactions are the main driving force for inhibitor-receptor binding. Overall, a good consistency between theoretical 3D-SQAR and molecular docking and MD simulation studies would provide directions for the design of new candidates, avoiding time-consuming and costly synthesis and biological evaluations. On the whole, the results derived from this study could expand the understanding of benzoxazole derivatives as anticancer agents and would be of great help in lead optimization for early drug discovery of highly potent anticancer activity targeting VEGFR-2.

Novel hKDR mouse model depicts the antiangiogenesis and apoptosis-promoting effects of neutralizing antibodies targeting vascular endothelial growth factor receptor 2

Vascular endothelial growth factor receptor 2 (VEGFR2)/KDR plays a critical role in tumor growth, diffusion, and invasion. The amino acid sequence homology of KDR between mouse and human in the VEGF ligand-binding domain was low, thus the WT mice could not be used to evaluate Abs against human KDR, and the lack of a suitable mouse model hindered both basic research and drug developments. Using the CRISPR/Cas9 technique, we successfully inserted different fragments of the human KDR coding sequence into the chromosomal mouse Kdr exon 4 locus to obtain an hKDR humanized mouse that can be used to evaluate the marketed Ab ramucirumab. In addition, the humanized mAb VEGFR-HK19 was developed, and a series of comparative assays with ramucirumab as the benchmark revealed that VEGFR-HK19 has higher affinity and superior antiproliferation activity. Moreover, VEGFR-HK19 selectively inhibited tumor growth in the hKDR mouse model but not in WT mice. The most important binding epitopes of VEGFR2-HK19 are D257, L313, and T315, located in the VEGF binding region. Therefore, the VEGFR2-HK19 Ab inhibits tumor growth by blocking VEGF-induced angiogenesis, inflammation, and promoting apoptosis. To our best knowledge, this novel humanized KDR mouse fills the gaps both in an animal model and the suitable in vivo evaluation method for developing antiangiogenesis therapies in the future, and the newly established humanized Ab is expected to be a drug candidate possibly benefitting tumor patients.

Immunogenicity of Monoclonal Antibodies and the Potential Use of HLA Haplotypes to Predict Vulnerable Patients

The use of monoclonal antibodies (mAbs) in the clinic has successfully expanded to treatment of cancer, viral infections, inflammations, and other indications. However, some of the classes of mAbs that are used in the clinic show the formation of anti-drug antibodies (ADAs) leading to loss of efficacy. This review describes ADA formation for the various mAbs, and its clinical effect. Lastly, this review considers the use of HLA-haplotypes as biomarkers to predict vulnerability of patients sensitive to formation of ADAs.

Ramucirumab in combination with dacarbazine in patients with progressive well-differentiated metastatic pancreatic neuroendocrine tumors (RamuNET): study protocol for a multicenter single-arm trial

BACKGROUND

Cytotoxic chemotherapy combinations and targeted agents represent established treatment concepts in advanced pancreatic neuroendocrine tumors (PNETs). However, response rates, side effects and outcome data strongly vary among these therapeutic approaches. Head-to-head comparisons between chemo- and molecular therapies are missing and secondary resistances frequently occur. The RamuNET trial aims to identify the effectiveness of dual treatment with DTIC and ramucirumab in progressive advanced PNET patients.

METHODS

The RamuNET study is an investigator-initiated multicenter prospective single-arm trial to evaluate the efficacy of ramucirumab in combination with dacarbazine (DTIC) over a period of at least 6 months. Patients with progressive well-differentiated and metastatic pancreatic neuroendocrine tumors are eligible. The study aims to include 45 patients over a period of 24 months with a minimum follow-up of 24 months. The primary endpoint is disease control after 6 months. Secondary endpoints include progression-free survival, biochemical response, overall survival, quality of life and toxicity. Based on the hypothesis that 80% of the patients can achieve a disease control after 6 months, the sample size calculation follows an exact binomial single-stage design. H0: p < =p0 = 60% versus H1: p > =p1 = 80%, alpha = 0.05, beta = 0.1.

DISCUSSION

This study investigates a new therapeutic approach using the combination of cytotoxic and targeted antiangiogenic therapy in advanced PNET. If positive, this trial will be the basis for a randomized two-arm study to investigate the combination of ramucirumab and DTIC against other established therapies in PNET.

TRIAL REGISTRATION

EudraCT: 2017-001207-68 . Date of registration: 2018.01.03.

Ramucirumab-related Oral Pyogenic Granuloma: A Report of Two Cases

Pyogenic granuloma (PG) is a granulomatous elevated lesion that occurs on the skin and mucous membranes. We herein report two cases of intra-oral PG that developed during the administration of ramucirumab for gastric cancer. Case 1 involved a 55-year-old man with a 6-mm tumor on the right tongue, and case 2 involved a 67-year-old man with a 5-mm tumor on the upper lip. The imbalance in angiogenesis caused by ramucirumab and the deterioration in the local oral environment were suggested to have caused the PG. Medical and dental collaboration is essential during the administration of ramucirumab.

Nanotechnology for angiogenesis: opportunities and challenges

Angiogenesis plays a critical role within the human body, from the early stages of life (i.e., embryonic development) to life-threatening diseases (e.g., cancer, heart attack, stroke, wound healing). Many pharmaceutical companies have expended huge efforts on both stimulation and inhibition of angiogenesis. During the last decade, the nanotechnology revolution has made a great impact in medicine, and regulatory approvals are starting to be achieved for nanomedicines to treat a wide range of diseases. Angiogenesis therapies involve the inhibition of angiogenesis in oncology and ophthalmology, and stimulation of angiogenesis in wound healing and tissue engineering. This review aims to summarize nanotechnology-based strategies that have been explored in the broad area of angiogenesis. Lipid-based, carbon-based and polymeric nanoparticles, and a wide range of inorganic and metallic nanoparticles are covered in detail. Theranostic and imaging approaches can be facilitated by nanoparticles. Many preparations have been reported to have a bimodal effect where they stimulate angiogenesis at low dose and inhibit it at higher doses.

Reactive cutaneous capillary endothelial proliferation in advanced hepatocellular carcinoma patients treated with camrelizumab: data derived from a multicenter phase 2 trial

Background

Association of immune-related adverse events with tumor response has been reported. Reactive cutaneous capillary endothelial proliferation (RCCEP) is the most common adverse event related to camrelizumab, an immune checkpoint inhibitor, but lack of comprehensive analyses. In this study, we conducted comprehensive analyses on RCCEP in advanced hepatocellular carcinoma (HCC) patients treated with camrelizumab monotherapy.

Methods

Data were derived from a Chinese nationwide, multicenter phase 2 trial of camrelizumab in pre-treated advanced HCC. The occurrence, clinicopathological characteristics, and prognostic value of RCCEP were analyzed.

Results

With a median follow-up of 12.5 months, 145 of the 217 camrelizumab-treated patients (66.8%) experienced RCCEP (all grade 1 or 2). RCCEP occurred on the skin surface, mainly on the skin surface of head, face, and trunk. RCCEP could be divided into 5 types including “red-nevus-like,” “pearl-like,” “mulberry-like,” “patch-like,” and “tumor-like,” according to the morphological features. RCCEP biopsy and pathology showed capillary endothelial hyperplasia and capillary hyperplasia in dermis. Significant association between RCCEP occurrence with higher objective response rate was observed (19.3% vs. 5.6%; one-sided p = 0.0044). Compared with those without RCCEP, patients with RCCEP had prolonged progression-free survival (median PFS; 3.2 months vs. 1.9 months; one-sided p < 0.0001) and overall survival (median OS; 17.0 months vs. 5.8 months; one-sided p < 0.0001). In multivariable analyses, the development of RCCEP was significantly associated with prolonged PFS and OS after adjusting for baseline covariates. In addition, the landmark analyses of PFS and OS were consistent with the unadjusted analysis.

Conclusions

RCCEP occurred on the skin surface and was an immune response of skin capillary endothelial cells. RCCEP occurrence positively associated with outcomes of camrelizumab in advanced HCC.

Potential Mechanisms of Cancer-Related Hypercoagulability

The association between cancer and thrombosis has been known for over a century and a half. However, the mechanisms that underlie this correlation are not fully characterized. Hypercoagulability in cancer patients can be classified into two main categories: Type I and Type II. Type I occurs when the balance of endogenous heparin production and degradation is disturbed, with increased degradation of endogenous heparin by tumor-secreted heparanase. Type II hypercoagulability includes all the other etiologies, with factors related to the patient, the tumor, and/or the treatment. Patients with poor performance status are at higher risk of venous thromboembolism (VTE). Tumors can result in VTE through direct pressure on blood vessels, resulting in stasis. Several medications for cancer are correlated with a high risk of thrombosis. These include hormonal therapy (e.g., tamoxifen), chemotherapy (e.g., cisplatin, thalidomide and asparaginase), molecular targeted therapy (e.g., lenvatinib, osimertinib), and anti-angiogenesis monoclonal antibodies (e.g., bevacizumab and ramucirumab).

Exposure-response relationship for ramucirumab from the randomized, double-blind, phase 3 REVEL trial (docetaxel versus docetaxel plus ramucirumab) in second-line treatment of metastatic non-small cell lung cancer

PURPOSE

Ramucirumab plus docetaxel improved survival in REVEL, a randomized phase 3 trial for patients with Stage IV non-small cell lung cancer after standard platinum-based chemotherapy. This exploratory analysis evaluated the exposure-response relationship of ramucirumab from REVEL.

METHODS

Patients received ramucirumab (10 mg/kg) or placebo plus docetaxel (75 mg/m2) every 3 weeks. Pharmacokinetic samples were collected. A population pharmacokinetic analysis predicted ramucirumab minimum concentration after first-dose administration (Cmin,1) and average concentration at steady state (Cave,ss). Predicted Cmin,1 and Cave,ss were used to evaluate the relationship between ramucirumab exposure and efficacy and safety, respectively. Exposure-efficacy was assessed by Kaplan-Meier and Cox regression analyses; exposure-safety was assessed by ordered categorical analyses.

RESULTS

Analyses included 376 patients treated with ramucirumab plus docetaxel and 366 patients treated with placebo plus docetaxel (364 for safety population). After adjusting for corresponding prognostic factors, the association between overall survival (OS) and Cmin,1 was statistically significant (p = 0.0110), although progression-free survival (PFS) showed a marginal association (p = 0.0515). At high ramucirumab exposures (Cmin,1), greater improvements (smaller hazard ratios) were seen for OS and PFS when stratified by Cmin,1 exposure quartiles. A statistically significant correlation was observed between ramucirumab Cave,ss and grade ≥ 3 febrile neutropenia and hypertension.

CONCLUSIONS

An association was observed between ramucirumab exposure and efficacy. Higher ramucirumab exposure was associated with improved clinical outcomes and increased toxicity in this analysis. Two exposure-response prospective randomized trials are being conducted to address causation (NCT02443883 and NCT02514551), with encouraging preliminary results (Ajani et al. in Ann Oncol 28:abstr 698P, 2017).

A critical review on ramucirumab in the treatment of advanced urothelial cancer

Advanced urothelial cancer (UC) is a lethal disease despite current advances in systemic therapy, including platinum chemotherapy combinations and immune checkpoint inhibition. Tumor angiogenesis is involved in UC growth and metastatic progression. Proangiogenic signaling through the VEGFR is a key process in UC with prognostic significance. Targeting of VEGFR2 with the monoclonal antibody ramucirumab has been tested in various different tumor types. In this review, we discuss the development of the drug in the context of its preclinical and clinical use with a focus on UC. Improvements in our ability to predict responses and resistance are key for maximizing its efficacy and selecting the most appropriate combinations with other active agents.

VEGFR2 targeted antibody fused with MICA stimulates NKG2D mediated immunosurveillance and exhibits potent anti-tumor activity against breast cancer

Binding of MHC class I-related chain molecules A and B (MICA/B) to the natural killer (NK) cell receptor NK group 2, member D (NKG2D) is thought critical for activating NK-mediated immunosurveillance. Angiogenesis is important for tumor growth and interfering with angiogenesis using the fully human IgG1 anti-VEGFR2 (vascular endothelial growth factor receptor 2) antibody (mAb04) can be effective in treating malignancy. In an effort to make mAb04 more effective we have generated a novel antibody fusion protein (mAb04-MICA) consisting of mAb04 and MICA. We found that mAb04-MICA maintained the anti-angiogenic and antineoplastic activities of mAb04, and also enhanced immunosurveillance activated by the NKG2D pathway. Moreover, in human breast tumor-bearing nude mice, mAb04-MICA demonstrated superior anti-tumor efficacy compared to combination therapy of mAb04 + Docetaxel or Avastin + Docetaxel, highlighting the immunostimulatory effect of MICA. In conclusion, mAb04-MICA provided new inspiration for anti-tumor treatment and had prospects for clinical application.

A three-time-point method for assessing kinetic parameters of 64Cu-labeled Ramucirumab trapping in VEGFR-2 positive lung tumors

OBJECTIVE

To describe a three-time-point method for estimating kinetic parameters involved in 64Cu-labeled Ramucirumab (64Cu-NOTA-RamAb) trapping of VEGFR-2 positive lung tumors.

MATERIALS AND METHODS

Positron emission tomography (microPET) data of tumor-bearing mice for 64Cu-NOTA-RamAb trapping in VEGFR-2 positive HCC4006 tumor were used, involving tissue activity measurements acquired at 3, 24 and 48 h post-injection, without and with administration of RamAb blocking dose. A kinetic model provided an analytical formula describing the tissue time-activity-curve, involving 64Cu-NOTA-RamAb uptake (Ki), release rate constant (kR) and fraction of free tracer in blood and interstitial volume (F).

RESULTS

Fitting analytical formula outcomes on mean microPET data yielded values of the kinetic parameters: Ki = 0.0314/0.0123 gram of blood per hour per gram of tissue, kR = 0.0387/0.0313 h-1 and F = 0.2075/0.2007 gram of blood per gram of tissue, without/with RamAb blocking dose, respectively (R = 0.99999 for the graph displaying microPET versus theoretical data; P < .01).

CONCLUSIONS

Three independent kinetic parameters (Ki, kR and F) can be assessed from three data points acquired at early, mid and late imaging, i.e., at 3, 24 and 48 h post-injection, for further characterization of 64Cu-NOTA-RamAb trapping in VEGFR-2 positive lung tumors.

A Review of Anti-Angiogenic Targets for Monoclonal Antibody Cancer Therapy

Tumor angiogenesis is a key event that governs tumor progression and metastasis. It is controlled by the complicated and coordinated actions of pro-angiogenic factors and their receptors that become upregulated during tumorigenesis. Over the past several decades, vascular endothelial growth factor (VEGF) signaling has been identified as a central axis in tumor angiogenesis. The remarkable advent of recombinant antibody technology has led to the development of bevacizumab, a humanized antibody that targets VEGF and is a leading clinical therapy to suppress tumor angiogenesis. However, despite the clinical efficacy of bevacizumab, its significant side effects and drug resistance have raised concerns necessitating the identification of novel drug targets and development of novel therapeutics to combat tumor angiogenesis. This review will highlight the role and relevance of VEGF and other potential therapeutic targets and their receptors in angiogenesis. Simultaneously, we will also cover the current status of monoclonal antibodies being developed to target these candidates for cancer therapy.

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

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

Phase I trial and pharmacokinetic study of tanibirumab, a fully human monoclonal antibody to vascular endothelial growth factor receptor 2, in patients with refractory solid tumors

Background Tanibirumab is a fully human monoclonal antibody to vascular endothelial growth factor receptor 2 (VEGFR-2). We conducted a first-in-human phase I study of tanibirumab in patients with solid tumors refractory to standard chemotherapy. Primary endpoints were evaluating safety, pharmacokinetics (PKs), estimating maximum-tolerated dose (MTD) and recommended phase II dose (RP2D). Methods We designed our study to escalate tanibirumab at 9 different dose levels with a 3 + 3 method and tanibirumab (1–28 mg/kg) was administered intravenously on D1, 8, 15 in 28-day courses. Dose limiting toxicities (DLTs) were only assessed during the first cycle of treatment and response evaluation was performed every 2 cycles. The effects of tanibirumab on several angiogenic factors were analyzed. Results From October 2011 to September 2013, a total of 26 patients with refractory solid tumors were enrolled. The median age was 58 years (range, 27–75) and 20 patients were male. The most common tumor type was colorectal cancer (N = 19) and seven patients had a history of previous bevacizumab treatment. As hemangioma continued to occur, the final dose level, 28 mg/kg, was not performed. DLTs were not found, and the MTD was confirmed to be 24 mg/kg. Hemangioma was observed in 16 patients (61.5%), but all were grade 1–2 and disappeared after discontinuation of the study drug. Among the 18 patients in the efficacy set, no objective response was observed, but 11 patients showed stable disease. PKs were characterized by dose-dependent linear exposure and the mean trough concentrations exceeded biologically relevant target levels at 12 mg/kg and above. Serum VEGF, soluble VEGFR-2, and PlGF increased at the 4 mg/kg dose level and above. Conclusions Treatment with tanibirumab showed a tolerable toxicity profile and modest clinical efficacy in patients with refractory solid tumors. A phase II trial of tanibirumab is ongoing now.

Safety and pharmacokinetics of ramucirumab in combination with docetaxel in Japanese patients with locally advanced or metastatic breast cancer: a Phase Ib study

OBJECTIVE

The primary objective of this study was to investigate the safety and tolerability and to confirm the recommended dose of the anti-vascular endothelial growth factor receptor 2 monoclonal antibody ramucirumab in combination with docetaxel in Japanese patients with metastatic/locally advanced breast cancer.

METHODS

In this multicenter, single-arm, Phase Ib trial, eligibility criteria included: 20 years or older, Eastern Cooperative Oncology Group performance status of 0/1 and confirmed diagnosis of human epidermal growth factor receptor 2-negative metastatic/locally recurrent inoperable breast adenocarcinoma. Patients received docetaxel (75 mg/m2) followed by ramucirumab (10 mg/kg) on Day 1 of 21-day cycles. Recommended dose was defined as <33% dose-limiting toxicities in dose-limiting toxicity-evaluable patients in Cycle 1. The safety, pharmacokinetics, immunogenicity and antitumor activity were examined.

RESULTS

Seven patients were treated. Most adverse events were mild to moderate. Two patients during Cycle 1 experienced a dose-limiting toxicity; one patient each experienced Grade 3 febrile neutropenia and Grade 3 gingivitis. Both dose-limiting toxicities subsequently resolved. No patients discontinued study therapies during Cycle 1. Four serious adverse events were possibly related to ramucirumab in combination with docetaxel. Anti-ramucirumab antibodies were not detected. Pharmacokinetic analysis revealed low total body clearance and long apparent terminal elimination half-life (~7-12 days). Partial response was reported in four patients.

CONCLUSIONS

The combination of ramucirumab and docetaxel was tolerable in female Japanese patients with breast cancer. Ramucirumab 10 mg/kg in combination with docetaxel (75 mg/m2) was confirmed as the recommended dose among Japanese patients, supporting its use in future studies.

SPECT imaging of neuropilin receptor type-1 expression with 131I-labeled monoclonal antibody

As a novel co-receptor for vascular endothelial growth factor (VEGF), neuropilin receptor type-1 (NRP-1) is overexpressed in several cancers and metastases, and serves as an attractive target for cancer molecular imaging and therapy. Previous single photon emission computerized tomography (SPECT) studies demonstrated that the small NRP-1-targeting peptides 99mTc-MA-ATWLPPR and 99mTc-CK3 showed poor tumor imaging quality, because of their rapid blood clearance and very low tumor uptake. Compared with small peptides, monoclonal antibodies (mAbs) can improve imaging of NRP-1-expression, due to their high affinity, specificity and slow extraction. A6-11-26 is a novel monoclonal antibody against NRP-1 b1b2 domain that exhibits inhibition of tumor growth in NPR-1-expressing preclinical models. The aim of the present study was to develop the 131I-labeled anti-NRP-1 monoclonal antibody A6-11-26 as a SPECT probe for imaging of NRP-1-positive tumor. An anti-NRP-1 monoclonal antibody (A6-11-26) was produced by hybridomas and was labeled with iodine-131 by the iodogen method. In vitro, the radiolabeling efficiency, radiochemical purity, immunoreactive fraction and stability were assessed. Binding affinity and specificity of 131I‑A6-11-26 to NRP-1 were evaluated using human glioblastoma U87MG cells. In vivo, biodistribution and SPECT/CT studies were conducted on mice bearing U87MG xenografts after the injection of 131I-A6-11-26 with or without co-injection of unlabeled A6-11-26 antibody. A6-11-26 was generated successfully by hybridoma with high purity (>95%) and was labeled with iodine-131 within 60 min with high labelling efficiency (95.46±3.34%), radiochemical purity (98.23±1.41%). 131I-A6-11-26 retained its immunoreactivity and also displayed excellent stability in mouse serum and PBS solution during 1 to 96 h. Cell uptake assays showed high NRP-1-specific uptake (15.80±1.30% applied activity at 6 h) in U87MG cells. 131I-A6-11-26 bound to NRP-1 with low nanomolar affinity (KD=1.67±0.14 nM) in U87MG cells. In vivo, biodistribution study demonstrated targeting of U87MG glioma xenografts was NRP-1 specific. The tumor uptake was 6.00±1.24%ID/g at 24 h, and the tumor to muscle ratio was 3.20±0.30 at 24 h, and reached the highest level of 6.13±0.24 at 120 h after injection. SPECT imaging studies revealed that 131I-A6-11-26 could clearly identify U87MG tumors with good contrast, especially at 72-120 h after injection. The present study demonstrates that 131I-A6-11-26 is capable of detecting lesions in an NRP-1-expressing tumor with high target selectivity, and may offer a promising SPECT agent for NRP-1 expression positive tumor and encourage further investigation.

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

INTRODUCTION

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

AREAS COVERED

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

Advances in systemic delivery of anti-cancer agents for the treatment of metastatic cancer

INTRODUCTION

The successful treatment of metastatic cancer is refractory to strategies employed to treat confined, primary lesions, such as surgical resection and radiation therapy, and thus must be addressed by systemic delivery of anti-cancer agents. Conventional systemically administered chemotherapeutics are often ineffective and come with severe dose-limiting toxicities.

AREAS COVERED

This review focuses on the recent developments in systemic therapy for metastatic cancer. Firstly, the strategies employed to improve the efficacy of conventional chemotherapeutics by 'passively' and 'actively' targeting them to tumors are discussed. Secondly, recent advances in the use of biologics to better target cancer and to instigate anti-tumor immunity are reviewed. Under the label of 'biologics', antibody-therapies, T cell engaging therapies, oncolytic virotherapies and cell-based therapies are examined and evaluated.

EXPERT OPINION

Improving specificity of action, and engaging the immune system appear to be key goals in the development of novel or reformulated anti-cancer agents for the treatment of metastatic cancer. One of the largest areas of opportunity in this field will be the identification of robust predictive biomarkers for use in conjunction with these agents. Treatment regimens that combine an agent to elicit an immune response (such as an oncolytic virus), and an agent to potentiate/mediate that immune response (such as immune checkpoint inhibitors) are predicted to be more effective than treatment with either agent alone.

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

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

PET Imaging of VEGFR-2 Expression in Lung Cancer with 64Cu-Labeled Ramucirumab

Lung cancer accounts for 17% of cancer-related deaths worldwide, and most patients present with locally advanced or metastatic disease. Novel PET imaging agents for assessing vascular endothelial growth factor receptor-2 (VEGFR-2) expression can be used for detecting VEGFR-2-positive malignancies and subsequent monitoring of therapeutic response to VEGFR-2-targeted therapies. Here, we report the synthesis and characterization of an antibody-based imaging agent for PET imaging of VEGFR-2 expression in vivo.

METHODS

Ramucirumab (named RamAb), a fully humanized IgG1 monoclonal antibody, was conjugated to 2-S-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA) and labeled with (64)Cu. Flow cytometry analysis and microscopy studies were performed to compare the VEGFR-2 binding affinity of RamAb and NOTA-RamAb. PET imaging and biodistribution studies were performed in nude mice bearing HCC4006 and A549 xenograft tumors. Ex vivo histopathology was performed to elucidate the expression patterns of VEGFR-2 in different tissues and organs to validate in vivo results.

RESULTS

Flow cytometry examination revealed the specific binding capacity of fluorescein isothiocyanate-RamAb to VEGFR-2, and no difference in VEGFR-2 binding affinity was seen between RamAb and NOTA-RamAb. After being labeled with (64)Cu, PET imaging revealed specific and prominent uptake of (64)Cu-NOTA-RamAb in VEGFR-2-positive HCC4006 tumors (9.4 ± 0.5 percentage injected dose per gram at 48 h after injection; n = 4) and significantly lower uptake in VEGFR-2-negative A549 tumors (4.3 ± 0.2 percentage injected dose per gram at 48 h after injection; n = 3). Blocking experiments revealed significantly lower uptake in HCC4006 tumors, along with histology analysis, further confirming the VEGFR-2 specificity of (64)Cu-NOTA-RamAb.

CONCLUSION

This study provides initial evidence that (64)Cu-NOTA-RamAb can function as a PET imaging agent for visualizing VEGFR-2 expression in vivo, which may also find potential applications in monitoring the treatment response of VEGFR-2-targeted cancer therapy.

Mechanisms of action of therapeutic antibodies for cancer

The therapeutic utility of antibodies and their derivatives is achieved by various means. The FDA has approved several targeted antibodies that disrupt signaling of various growth factor receptors for the treatment of a number of cancers. Rituximab, and other anti-CD20 monoclonal antibodies are active in B cell malignancies. As more experience has been gained with anti-CD20 monoclonal antibodies, the multifactorial nature of their anti-tumor mechanisms has emerged. Other targeted antibodies function to dampen inhibitory checkpoints. These checkpoint inhibitors have recently achieved dramatic results in several cancers, including melanoma. These and related antibodies continue to be investigated in the clinical and pre-clinical settings. Novel antibody structures that target two or more antigens have also made their way into clinical use. Tumor targeted antibodies can also be conjugated to chemo- or radiotherapeutic agents, or catalytic toxins, as a means to deliver toxic payloads to cancer cells. Here we provide a review of these mechanisms and a discussion of their relevance to current and future clinical applications.

Anti-angiogenic agents in metastatic colorectal cancer

Colorectal cancer (CRC) is a major public health concern being the third leading cause of cancer mortality in the United States. The availability of better therapeutic options has led to a decline in cancer mortality in these patients. Surgical resection should be considered in all stages of the disease. The use of conversion therapy has made surgery a potentially curative option even in patients with initially unresectable metastatic disease. In this review we discuss the role of various anti-angiogenic agents in patients with metastatic CRC (mCRC). We describe the mechanism of action of these agents, and the rationale for their use in combination with chemotherapy. We also review important clinical studies that have evaluated the safety and efficacy of these agents in mCRC patients. Despite the discovery of several promising anti-angiogenic agents, mCRC remains an incurable disease with a median overall survival of just over 2 years in patients exposed to all available treatment regimens. Further insights into tumor biology and tumor microenvironment may help improve outcomes in these patients.

TTAC-0001, a human monoclonal antibody targeting VEGFR-2/KDR, blocks tumor angiogenesis

Angiogenesis is one of the most important processes for cancer cell survival, tumor growth and metastasis. Vascular endothelial growth factor (VEGF) and its receptor, particularly VEGF receptor-2 (VEGFR-2, or kinase insert domain-containing receptor, KDR), play critical roles in tumor-associated angiogenesis. We developed TTAC-0001, a human monoclonal antibody against VEGFR-2/KDR from a fully human naïve single-chain variable fragment phage library. TTAC-0001 was selected as a lead candidate based on its affinity, ligand binding inhibition and inhibition of VEGFR-2 signal in human umbilical vein endothelial cells (HUVEC). TTAC-0001 inhibited binding of VEGF-C and VEGF-D to VEGFR-2 in addition to VEGF-A. It binds on the N-terminal regions of domain 2 and domain 3 of VEGFR-2. It could inhibit the phosphorylation of VEGFR-2/KDR and ERK induced by VEGF in HUVEC. TTAC-0001 also inhibited VEGF-mediated endothelial cell proliferation, migration and tube formation in vitro, as well as ex vivo vessel sprouting from rat aortic rings and neovascularization in mouse matrigel model in vivo. Our data indicates that TTAC-0001 blocks the binding of VEGFs to VEGFR-2/KDR and inhibits VEGFR-induced signaling pathways and angiogenesis. Therefore, these data strongly support the further development of TTAC-0001 as an anti-cancer agent in the clinic.

Clinical advances in the development of novel VEGFR2 inhibitors

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

Clinical experience with ramucirumab : outcomes in breast cancer

INTRODUCTION

Monoclonal antibodies and small molecules targeting the VEGF pathway are part of the arsenal to treat malignant tumors. Antiangiogenesis therapies has been studied in breast cancer with partial success, reflected by the approval of bevacizumab in Europe but not in United States, for metastatic breast cancer (mBC). Ramucirumab is a mAb against VEGFR-2 interfering with the normal activation of this receptor by its natural ligand VEGF.

AREAS COVERED

This article will review the preclinical data available to date for ramucirumab, as well as survey the main clinical trials of antiangiogenic agents reported in breast cancer, focusing on Phase III clinical trials. It will also review the clinical trial data for ramucirumab in mBC, including the design of the Phase II trials, and report on the preliminary results of the TRIO-012 trial. This trial did not meet its primary end point in progression-free survival and has to be considered as a negative trial.

EXPERT OPINION

Despite preliminary positive data with ramucirumab in other metastatic solid tumors reported to date, the results of TRIO-012 discourage pursuing more efforts with ramucirumab in mBC unless predictive and reproducible biomarkers can be established to select those patients who are most likely to benefit from it.

Anti-angiogenic agent ramucirumab: meaningful or marginal?

Ramucirumab (IMC-1121B) targets VEGFR-2. Ramucirumab is being investigated in many malignancies including gastric cancer. The Phase III trial in patients with advanced breast cancer failed to improve the primary end point The REGARD trial, a Phase III study, in patients with advanced gastric cancer in the second line setting, had a marginal improvement in overall survival but did not achieve the expected hazard ratio target (of 0.69) and the median duration of therapy with ramucirumab was meager 8 weeks (only 2 weeks longer than the placebo's). Other notable agents in the second line setting are docetaxel and irinotecan. Preliminary results of the RAINBOW trial suggest that ramucirumab may be providing more than marginal advantage. In this review, we briefly summarize the process of angiogenesis and address the emerging cost-benefit issues that surround all newly developed agents including ramucirumab.

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

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

Anti-VEGF- and anti-VEGF receptor-induced vascular alteration in mouse healthy tissues

Systemic therapy with anti-VEGF drugs such as bevacizumab is widely used for treatment of human patients with various solid tumors. However, systemic impacts of such drugs in host healthy vasculatures remain poorly understood. Here, we show that, in mice, systemic delivery of an anti-VEGF or an anti-VEGF receptor (VEGFR)-2 neutralizing antibody caused global vascular regression. Among all examined tissues, vasculatures in endocrine glands, intestinal villi, and uterus are the most affected in response to VEGF or VEGFR-2 blockades. Thyroid vascular fenestrations were virtually completely blocked by VEGF blockade, leading to marked accumulation of intraendothelial caveolae vesicles. VEGF blockade markedly increased thyroid endothelial cell apoptosis, and withdrawal of anti-VEGF resulted in full recovery of vascular density and architecture after 14 d. Prolonged anti-VEGF treatment resulted in a significant decrease of the circulating level of the predominant thyroid hormone free thyroxine, but not the minimal isoform of triiodothyronine, suggesting that chronic anti-VEGF treatment impairs thyroid functions. Conversely, VEGFR-1-specific blockade produced virtually no obvious phenotypes. These findings provide structural and functional bases of anti-VEGF-specific drug-induced side effects in relation to vascular changes in healthy tissues. Understanding anti-VEGF drug-induced vascular alterations in healthy tissues is crucial to minimize and even to avoid adverse effects produced by currently used anti-VEGF-specific drugs.

Ramucirumab: a novel antiangiogenic agent

Ramucirumab (IMC-1121B) is a fully humanized monoclonal antibody that binds to VEGFR2 and can inhibit angiogenesis, a quintessential mechanism for promoting tumor growth and metastasis. Several antiangiogenesis agents are already approved for cancer therapy; however, ramucirumab's selectivity for VEGFR2 makes it interesting. The selectivity of an agent can improve safety and efficacy. This article describes the mechanism of action, pharmacokinetics, safety and clinical trial results of ramucirumab with particular emphasis on gastric cancer.

Monoclonal antibodies in gastrointestinal cancers

INTRODUCTION

Among gastrointestinal cancers, colorectal and gastric neoplasms are the most frequent. The development of new targeted drugs improved the efficacy of systemic therapy in advanced stages of those malignancies.

AREAS COVERED

This review highlights the main biological processes implicated in gastrointestinal cancer development and progression, such as angiogenesis and epidermal growth factor receptor (EGFR) signaling pathway. On these bases, anti-EGFR and anti-vascular endothelial growth factor (VEGF) monoclonal antibodies in colorectal and gastric cancer are discussed. Data about further monoclonal antibodies in development are also reported.

EXPERT OPINION

The use of monoclonal antibodies in colorectal and gastric cancers showed the best outcomes when combined with chemotherapy, even though single agent anti-EGFR antibodies seem active in particular setting of metastatic colorectal cancer (CRC) patients. It is not well defined whether the addition of anti-VEGF and anti-EGFR to chemotherapy could improve outcome in those patients susceptible to CRC-related metastases resection. Little and conflicting data are available about the role of these drugs in adjuvant setting. Tests are available to select patients with higher probability to get benefit from these treatments. Further biomarkers need to be evaluated to improve this selection and achieve "tailorization" of systemic therapy.

Structure, development, preclinical and clinical efficacy of tivozanib (KRN-951, AV-951)

Tivozanib hydrochloride monohydrate (tivozanib; formerly KRN-951, AV-951) is a potent pan-VEGF receptor tyrosine kinase inhibitor. The biological activity of tivozanib seems to outstand that of other VEGF tyrosine kinase inhibitors. In Phase I studies, observed side effects are generally mild, with hypertension being the most common adverse event. In single-agent Phase II and III studies in patients with advanced or metastatic renal cell carcinoma, tivozanib has demonstrated convincing clinical activity. Further clinical trials of tivozanib combined with various cytotoxic drug regimens as well as other classes of target-specific anticancer agents (e.g., mTOR inhibitors) for other indications are underway. Tivozanib has not yet been approved for regular use.

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.

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.

The current state of targeted agents in rectal cancer

Targeted biologic agents have an established role in treating metastatic colorectal cancer (CRC), and the integration of targeted therapies into the treatment of CRC has resulted in significant improvements in outcomes. Rapidly growing insight into the molecular biology of CRC, as well as recent developments in gene sequencing and molecular diagnostics, has led to high expectations for the identification of molecular markers to be used in personalized treatment regimens. The mechanisms of action and toxicities of targeted therapies differ from those of traditional cytotoxic chemotherapy. Targeted therapy has raised new insight about the possibility of tailoring treatment to an individual's disease, the assessment of drug effectiveness and toxicity, and the economics of cancer care. This paper covers the last decade of clinical trials that have explored the toxicity and efficacy of targeted agents in locally advanced and metastatic CRC and how their role may benefit patients with rectal cancer. Future efforts should include prospective studies of these agents in biomarker-defined subpopulations, as well as studies of novel agents that target angiogenesis, tumor-stromal interaction, and the cell signaling pathways implicated in rectal cancer.

Bevacizumab and breast cancer: what does the future hold?

Breast cancer is a major health concern for many women, but despite the current standard therapies, many women still die of metastatic disease. Angiogenesis has been evaluated as a possible target for therapy and bevacizumab (Avastin(®), Genentech/Roche, CA, USA), a monoclonal antibody against VEGF-A, has been developed to target this. Current clinical trials utilizing bevacizumab have shown an increase in progression-free survival, but this has not translated to an increase in overall survival in breast cancer patients. In this article, we summarize the currently published trials utilizing bevacizumab in the treatment of breast cancer and describe various methods of measuring angiogenesis in vitro and in vivo. We also describe the related process of lymphangiogenesis, as this may contribute to the mechanism of cancer progression and may be a potential target for therapy in the future. Understanding these processes may help us develop new treatments for breast cancer.

Targeting the vasculature of visceral tumors: novel insights and treatment perspectives

BACKGROUND

Angiogenesis, the formation of new blood vessels from the endothelium of the existing vasculature, describes a crucial process in tumor growth, disease progression, and metastasis. Therefore, the upcoming strategy of inhibiting tumor angiogenesis has generated different treatment modalities, which have been transferred into clinical practice in recent years. Currently, this concept is applied to target the vasculature of different visceral tumors and intensive clinical research has just started.

MATERIALS AND METHODS

This review summarizes the modifications of systemic treatment of visceral tumors by targeting the vasculature in the past years. Moreover, novel targets and treatment strategies will be discussed to evaluate future directions.

RESULTS

Leading antiangiogenic drugs combined with systemic chemotherapy have been applied with increasing success during the last years. Therefore, the concept of combining vascular targeting agents with established chemotherapeutic regimens has been increasingly adopted into the therapies of different visceral tumors.

CONCLUSION

Targeting the vasculature of visceral tumors in combination with established standard tumor therapies includes major clinical potential for future therapy concepts.

Tanibirumab (TTAC-0001): a fully human monoclonal antibody targets vascular endothelial growth factor receptor 2 (VEGFR-2)

Vascular endothelial growth factor (VEGF) binds to its receptor (VEGFR) and stimulates angiogenesis, an important step in tumor growth and metastasis. Several anticancer therapies targeting VEGFR with small molecules and antibody have been currently studied in preclinical and clinical studies. This article provides a review of human monoclonal antibody tanibirumab (TTAC-0001), which specifically binds VEGFR-2 and is currently being developed in preclinical stage by PharmAbcine (Daejon, Korea).

Aflibercept in the treatment of metastatic colorectal cancer

Colorectal cancer is the third most common cancer in the US. In recent decades, an improved understanding of the role of the angiogenesis pathway in colorectal cancer has led to advancements in treatment. Bevacizumab has been shown to improve the progression-free survival and overall survival when combined with cytotoxic chemotherapy in patients with metastatic colorectal cancer, and at present is the only antiangiogenesis agent approved for the treatment of this cancer. Aflibercept is a novel angiogenesis-targeting agent, and has demonstrated efficacy in treating metastatic colorectal cancer in a recent randomized Phase III trial. Here we review the role of angiogenesis in the tumorigenesis of colorectal cancer, strategies for targeting angiogenesis, and the clinical development of aflibercept.