Trebananib (AMG 386) plus weekly paclitaxel with or without bevacizumab as first-line therapy for HER2-negative locally recurrent or metastatic breast cancer: A phase 2 randomized study

Natural products‐based antiangiogenic agents: New frontiers in cancer therapy

Angiogenesis, vital for tumor growth and metastasis, is a promising target in cancer therapy. Natural compounds offer potential as antiangiogenic agents with reduced toxicity. This review provides a comprehensive overview of natural product‐based antiangiogenic therapies, focusing on molecular mechanisms and therapeutic potential. A systematic search identified relevant articles from 2019 to 2023. Various natural compounds, including polyphenols, terpenes, alkaloids, cannabinoids, omega‐3 fatty acids, polysaccharides, proteins, and carotenoids, were investigated for their antiangiogenic properties. Challenges such as dose standardization, routes of administration, and potential side effects remain. Further studies, including in‐depth animal models and human epidemiological studies, must elucidate clinical efficacy and safety. Synergistic effects with current antiangiogenic therapies, such as bevacizumab and tyrosine kinase inhibitors, should be explored. Additionally, the potential hormone‐dependent effects of compounds like genistein highlight the need for safety evaluation. In conclusion, natural products hold promise as adjunctive therapies to conventional antineoplastic drugs in modulating angiogenesis in cancer. However, robust clinical trials are needed to validate preclinical findings and ensure safety and efficacy.

Evaluating the efficacy and safety of trebananib in treating ovarian cancer and non-ovarian cancer patients: a meta-analysis and systematic review

OBJECTIVES

Due to its anti-angiogenic properties, trebananib is frequently employed in the treatment of cancer patients, particularly those with ovarian cancer. We conducted a meta-analysis to assess the efficacy and safety profile of trebananib in combination with other drugs for treating both ovarian and non-ovarian cancer patients.

METHODS

Our search encompassed PubMed, Medline, Cochrane, and Embase databases, with a focus on evaluating study quality. Data extraction was conducted from randomized controlled trials (RCTs), and RevMan 5.3 facilitated result analysis.

RESULTS

Combining trebananib with other drugs extended progression-free survival (PFS) [HR 0.81, (95%CI: 0.65, 0.99), p = 0.04] and overall survival (OS) [HR 0.88, (95%CI: 0.79, 1.00), p = 0.04] in ovarian cancer patients. Ovarian cancer patients exhibited a higher objective response rate (ORR) with trebananib compared to non-ovarian cancer cohorts. Moreover, the incorporation of trebananib into the standard treatment regimen for malignant tumors did not significantly elevate drug-related adverse events [RR 1.05, (95% CI: 1.00, 1.11), p = 0.05].

CONCLUSION

Trebananib plus other drugs can improve the PFS, OS and ORR in patients with cancer, especially ovarian cancer. Our recommendation is to use trebananib plus other drugs to treat advanced cancer, and to continuously monitor and manage drug-related adverse events.

REGISTRATION

PROSPERO (No. CRD42023466988).

Neoadjuvant Trebananib plus Paclitaxel-based Chemotherapy for Stage II/III Breast Cancer in the Adaptively Randomized I-SPY2 Trial-Efficacy and Biomarker Discovery

PURPOSE

The neutralizing peptibody trebananib prevents angiopoietin-1 and angiopoietin-2 from binding with Tie2 receptors, inhibiting angiogenesis and proliferation. Trebananib was combined with paclitaxel±trastuzumab in the I-SPY2 breast cancer trial.

PATIENTS AND METHODS

I-SPY2, a phase II neoadjuvant trial, adaptively randomizes patients with high-risk, early-stage breast cancer to one of several experimental therapies or control based on receptor subtypes as defined by hormone receptor (HR) and HER2 status and MammaPrint risk (MP1, MP2). The primary endpoint is pathologic complete response (pCR). A therapy "graduates" if/when it achieves 85% Bayesian probability of success in a phase III trial within a given subtype. Patients received weekly paclitaxel (plus trastuzumab if HER2-positive) without (control) or with weekly intravenous trebananib, followed by doxorubicin/cyclophosphamide and surgery. Pathway-specific biomarkers were assessed for response prediction.

RESULTS

There were 134 participants randomized to trebananib and 133 to control. Although trebananib did not graduate in any signature [phase III probabilities: Hazard ratio (HR)-negative (78%), HR-negative/HER2-positive (74%), HR-negative/HER2-negative (77%), and MP2 (79%)], it demonstrated high probability of superior pCR rates over control (92%-99%) among these subtypes. Trebananib improved 3-year event-free survival (HR 0.67), with no significant increase in adverse events. Activation levels of the Tie2 receptor and downstream signaling partners predicted trebananib response in HER2-positive disease; high expression of a CD8 T-cell gene signature predicted response in HR-negative/HER2-negative disease.

CONCLUSIONS

The angiopoietin (Ang)/Tie2 axis inhibitor trebananib combined with standard neoadjuvant therapy increased estimated pCR rates across HR-negative and MP2 subtypes, with probabilities of superiority >90%. Further study of Ang/Tie2 receptor axis inhibitors in validated, biomarker-predicted sensitive subtypes is warranted.

Circulating inflammatory cells in patients with metastatic breast cancer: Implications for treatment

Adaptive and innate immune cells play a crucial role as regulators of cancer development.

Inflammatory cells in blood flow seem to be involved in pro-tumor activities and contribute to breast cancer progression. Circulating lymphocyte ratios such as the platelet-lymphocytes ratio (PLR), the monocyte-lymphocyte ratio (MLR) and the neutrophil-lymphocyte ratio (NLR) are new reproducible, routinely feasible and cheap biomarkers of immune response. These indexes have been correlated to prognosis in many solid tumors and there is growing evidence on their clinical applicability as independent prognostic markers also for breast cancer.

In this review we give an overview of the possible value of lymphocytic indexes in advanced breast cancer prognosis and prediction of outcome. Furthermore, targeting the immune system appear to be a promising therapeutic strategy for breast cancer, especially macrophage-targeted therapies. Herein we present an overview of the ongoing clinical trials testing systemic inflammatory cells as therapeutic targets in breast cancer.

Novel Drugs with High Efficacy against Tumor Angiogenesis

Angiogenesis is involved in physiological and pathological processes in the body. Tumor angiogenesis is a key factor associated with tumor growth, progression, and metastasis. Therefore, there is great interest in developing antiangiogenic strategies. Hypoxia is the basic initiating factor of tumor angiogenesis, which leads to the increase of vascular endothelial growth factor (VEGF), angiopoietin (Ang), hypoxia-inducible factor (HIF-1), etc. in hypoxic cells. The pathways of VEGF and Ang are considered to be critical steps in tumor angiogenesis. A number of antiangiogenic drugs targeting VEGF/VEGFR (VEGF receptor) or ANG/Tie2, or both, are currently being used for cancer treatment, or are still in various stages of clinical development or preclinical evaluation. This article aims to review the mechanisms of angiogenesis and tumor angiogenesis and to focus on new drugs and strategies for the treatment of antiangiogenesis. However, antitumor angiogenic drugs alone may not be sufficient to eradicate tumors. The molecular chaperone heat shock protein 90 (HSP90) is considered a promising molecular target. The VEGFR system and its downstream signaling molecules depend on the function of HSP90. This article also briefly introduces the role of HSP90 in angiogenesis and some HSP90 inhibitors.

Novel Pathways for Targeting Tumor Angiogenesis in Metastatic Breast Cancer

Breast cancer is the most common cancer affecting women and is the second leading cause of cancer related death worldwide. Angiogenesis, the process of new blood vessel development from pre-existing vasculature, has been implicated in the growth, progression, and metastasis of cancer. Tumor angiogenesis has been explored as a key therapeutic target for decades, as the blockade of this process holds the potential to reduce the oxygen and nutrient supplies that are required for tumor growth. However, many existing anti-angiogenic approaches, such as those targeting Vascular Endothelial Growth Factor, Notch, and Angiopoietin signaling, have been associated with severe side-effects, limited survival advantage, and enhanced cancer regrowth rates. To address these setbacks, alternative pathways involved in the regulation of tumor angiogenesis are being explored, including those involving Bone Morphogenetic Protein-9 signaling, the Sonic Hedgehog pathway, Cyclooxygenase-2, p38-mitogen-activated protein kinase, and Chemokine Ligand 18. This review article will introduce the concept of tumor angiogenesis in the context of breast cancer, followed by an overview of current anti-angiogenic therapies, associated resistance mechanisms and novel therapeutic targets.

Ang2 inhibitors and Tie2 activators: potential therapeutics in perioperative treatment of early stage cancer

Anti-angiogenic drugs targeting the VEGF pathway are most effective in advanced metastatic disease settings of certain types of cancers, whereas they have been unsuccessful as adjuvant therapies of micrometastatic disease in numerous phase III trials involving early-stage (resectable) cancers. Newer investigational anti-angiogenic drugs have been designed to inhibit the Angiopoietin (Ang)-Tie pathway. Acting through Tie2 receptors, the Ang1 ligand is a gatekeeper of endothelial quiescence. Ang2 is a dynamically expressed pro-angiogenic destabilizer of endothelium, and its upregulation is associated with poor prognosis in cancer. Besides using Ang2 blockers as inhibitors of tumor angiogenesis, little attention has been paid to their use as stabilizers of blood vessels to suppress tumor cell extravasation and metastasis. In clinical trials, Ang2 blockers have shown limited efficacy in advanced metastatic disease settings. This review summarizes preclinical evidence suggesting the potential utility of Ang2 inhibitors or Tie2 activators as neoadjuvant or adjuvant therapies in the prevention or treatment of early-stage micrometastatic disease. We further discuss the rationale and potential of combining these strategies with immunotherapy, including immune checkpoint targeting antibodies.

Risk of hypertension with anti-VEGF monoclonal antibodies in cancer patients: a systematic review and meta-analysis of 105 phase II/III randomized controlled trials

We performed a meta-analysis to fully investigate the hypertension of anti-VEGF mAbs in cancer patients. Databases were searched for randomized controlled trials (RCTs) treated with anti-VEGF mAbs till January 2021. The relevant RCTs in cancer patients treated with anti-VEGF mAbs were retrieved and the systematic evaluation was conducted. One hundred and five RCTs and 65358 patients were included. Our study suggests that anti-VEGF mAbs significantly increased the risks of all-grade (RR, 3.22; 95%CI, 2.83-3.65; p < 0.00001; I²=71%) and high-grade (RR, 6.15; 95%CI, 5.58-6.78; p < 0.00001; I²=48%) hypertension in cancer patients. Those risks may be dependent on drug type. Icrucumab did not association with an increased risk of hypertension. The RR of hypertension did not vary significantly according to the type of cancer, line of therapy, and treatment duration. The available data suggested that the use of anti-VEGF mAbs were associated with a significantly increased risk of hypertension.

Angiopoietin inhibitors: A review on targeting tumor angiogenesis

Angiogenesis is the process of formation of new blood vessels from existing ones. Vessels serve the purpose of providing oxygen, nutrients and removal of waste from the cells. The physiological angiogenesis is a normal process and is required in the embryonic development, wound healing, menstrual cycle. For homeostasis, balance of pro angiogenic factors and anti angiogenic factors like is important. Their imbalance causes a process known as "angiogenic switch" which leads to various pathological conditions like inflammation, tumor and restenosis. Like normal cells, tumor cells also require oxygen and nutrients to grow which is provided by tumor angiogenesis. Hence angiogenic process can be inhibited to prevent tumor growth. This gives rise to study of anti angiogenic drugs. Currently approved anti angiogenic drugs are mostly VEGF inhibitors, but VEGF inhibitors have certain limitations like toxicity, low progression free survival (PFS), and resistance to anti VEGF therapy. This article focuses on angiopoietins as alternative and potential targets for anti angiogenic therapy. Angiopoietins are ligands of Tie receptor and play a crucial role in angiogenesis, their inhibition can prevent many tumor growths even on later stages of development. We present current clinical and preclinical stages of angiopoietin inhibitors. Drugs studied in the article are selective as well as non-selective inhibitors of angiopoietin 2 like Trebananib (AMG 386), AMG 780, REGN 910, CVX 060, MEDI 3617 and dual inhibitors of angiopoietin 2 and VEGF like Vanucizumab and RG7716. The angiopoietin inhibitors show promising results alone and in combination with VEGF inhibitors in various malignancies.

Role of Tumor-Associated Macrophages in Sarcomas

Simple Summary

Recent studies have shown the pro-tumoral role of tumor-associated macrophages (TAMs) not only in major types of carcinomas but also in sarcomas. Several types of TAM-targeted drugs have been investigated under clinical trials, which may represent a novel therapeutic approach for bone and soft-tissue sarcomas.

Abstract

Sarcomas are complex tissues in which sarcoma cells maintain intricate interactions with their tumor microenvironment. Tumor-associated macrophages (TAMs) are a major component of tumor-infiltrating immune cells in the tumor microenvironment and have a dominant role as orchestrators of tumor-related inflammation. TAMs promote tumor growth and metastasis, stimulate angiogenesis, mediate immune suppression, and limit the antitumor activity of conventional chemotherapy and radiotherapy. Evidence suggests that the increased infiltration of TAMs and elevated expression of macrophage-related genes are associated with poor prognoses in most solid tumors, whereas evidence of this in sarcomas is limited. Based on these findings, TAM-targeted therapeutic strategies, such as inhibition of CSF-1/CSF-1R, CCL2/CCR2, and CD47/SIRPα, have been developed and are currently being evaluated in clinical trials. While most of the therapeutic challenges that target sarcoma cells have been unsuccessful and the prognosis of sarcomas has plateaued since the 1990s, several clinical trials of these strategies have yielded promising results and warrant further investigation to determine their translational benefit in sarcoma patients. This review summarizes the roles of TAMs in sarcomas and provides a rationale and update of TAM-targeted therapy as a novel treatment approach for sarcomas.

ΔNp73/ETS2 complex drives glioblastoma pathogenesis- targeting downstream mediators by rebastinib prolongs survival in preclinical models of glioblastoma

BACKGROUND

Glioblastoma (GBM) remains one of the least successfully treated cancers. It is essential to understand the basic biology of this lethal disease and investigate novel pharmacological targets to treat GBM. The aims of this study were to determine the biological consequences of elevated expression of ΔNp73, an N-terminal truncated isoform of TP73, and to evaluate targeting of its downstream mediators, the angiopoietin 1 (ANGPT1)/tunica interna endothelial cell kinase 2 (Tie2) axis, by using a highly potent, orally available small-molecule inhibitor (rebastinib) in GBM.

METHODS

ΔNp73 expression was assessed in glioma sphere cultures, xenograft glioblastoma tumors, and glioblastoma patients by western blot, quantitative reverse transcription PCR, and immunohistochemistry. Immunoprecipitation, chromatin immunoprecipitation (ChiP) and sequential ChIP were performed to determine the interaction between ΔNp73 and E26 transformation-specific (ETS) proto-oncogene 2 (ETS2) proteins. The oncogenic consequences of ΔNp73 expression in glioblastomas were examined by in vitro and in vivo experiments, including orthotopic zebrafish and mouse intracranial-injection models. Effects of rebastinib on growth of established tumors and survival were examined in an intracranial-injection mouse model.

RESULTS

ΔNp73 upregulates both ANGPT1 and Tie2 transcriptionally through ETS conserved binding sites on the promoters by interacting with ETS2. Elevated expression of ΔNp73 promotes tumor progression by mediating angiogenesis and survival. Therapeutic targeting of downstream ΔNp73 signaling pathways by rebastinib inhibits growth of established tumors and extends survival in preclinical models of glioblastoma.

CONCLUSION

Aberrant expression of ΔNp73 in GBM promotes tumor progression through autocrine and paracrine signaling dependent on Tie2 activation by ANGPT1. Disruption of this signaling by rebastinib improves tumor response to treatment in glioblastoma.

HIFs, angiogenesis, and metabolism: elusive enemies in breast cancer

Hypoxia-inducible factors (HIFs) and the HIF-dependent cancer hallmarks angiogenesis and metabolic rewiring are well-established drivers of breast cancer aggressiveness, therapy resistance, and poor prognosis. Targeting of HIF and its downstream targets in angiogenesis and metabolism has been unsuccessful so far in the breast cancer clinical setting, with major unresolved challenges residing in target selection, development of robust biomarkers for response prediction, and understanding and harnessing of escape mechanisms. This Review discusses the pathophysiological role of HIFs, angiogenesis, and metabolism in breast cancer and the challenges of targeting these features in patients with breast cancer. Rational therapeutic combinations, especially with immunotherapy and endocrine therapy, seem most promising in the clinical exploitation of the intricate interplay of HIFs, angiogenesis, and metabolism in breast cancer cells and the tumor microenvironment.

A Systematic Review and Meta-Analysis of Bevacizumab in First-Line Metastatic Breast Cancer: Lessons for Research and Regulatory Enterprises

BACKGROUND

The US Food and Drug Administration's accelerated approval and later withdrawal of bevacizumab in patients with metastatic breast cancer (mBC) is a seminal case for ongoing debates about the validity of using progression-free survival (PFS) as a surrogate measure for overall survival (OS) in cancer drug approvals. We systematically reviewed and meta-analyzed the evidence around bevacizumab's regulatory approval and withdrawal in mBC.

METHODS

We searched for all published phase II or III clinical trials testing bevacizumab as a first-line therapy for patients with mBC. Data were extracted on trial demographics, interventions, and outcomes. Descriptive analysis was stratified by whether the trial was initiated before, during, or after the accelerated approval. We used a cumulative random-effects meta-analysis to assess the evolution of evidence of the effect of bevacizumab on PFS and OS. We estimated the association between the trial-level PFS and OS effect using a nonlinear mixed-regression model.

RESULTS

Fifty-two studies were included. Trial activity dramatically dropped after the accelerated approval was withdrawn. Eight clinical trials reported hazard ratios (hazard ratios) and were meta-analyzed. The cumulative hazard ratio for PFS was 0.72 (95% CI = 0.65 to 0.79), and the cumulative hazard ratio for OS was 0.90 (95% CI = 0.80 to 1.01). The regression model showed a statistically nonsignificant association between PFS benefit and OS benefit (β = 0.43, SE = 0.81).

CONCLUSION

The US Food and Drug Administration's decision-making in this case was consistent with the evolving state of evidence. However, the fact that seven clinical trials are insufficient to conclude validity (or lack thereof) for a trial-level surrogate suggests that it would be more efficient to conduct trials using the more clinically meaningful endpoints.

Efficacy of bevacizumab combined with chemotherapy in the treatment of HER2-negative metastatic breast cancer: a network meta-analysis

BACKGROUND

It is not known what combination of bevacizumab and chemotherapy agents is the best therapeutic regimen. Comparative study results among the efficacies of bevacizumab plus chemotherapy remain controversial in patients with HER2-negative metastatic breast cancer.

METHODS

We searched Pubmed, Embase, and Cochrane Library Central Resister of Controlled Trials through were July 2019 for randomized controlled trials that evaluated the efficacy of bevacizumab plus chemotherapy in HER2-negative metastatic breast cancer. Data on included study characteristics, outcomes, and risk of bias were abstracted by two reviewers.

RESULTS

A total of 16 RCT studies involving 5689 patients were included. The results showed that bevacizumab (Bev) - taxanes (Tax) - capecitabine (Cap) has highest-ranking and is probably more effective for prolonging progression-free survival (PFS) than Tax, Cap, Bev-Tax and Bev-Cap, which was no convincing differences among Bev-Cap-vinorelbine, Bev-Tax-everolimus, Bev-Tax-trebananib, Bev-exemestane, Bev-Cap-cyclophosphamide in Bev-containing regimens. For overall response rate (ORR), Bev-Tax-Cap is superior to Tax, Cap and Bev-Cap, while Bev-Tax-trebananib is superior to Cap. The cumulative probability ranking showed that Bev-Tax-Cap or Bev-Tax-trebananib may have best pathological response rate in HER2-negative metastatic breast cancer.

CONCLUSION

Our results provide moderate quality evidence that bevacizumab-taxanes-capecitabine maybe the most effective bevacizumab plus chemotherapy on PFS and ORR in HER2-negative metastatic breast cancer, however it should be also considered that bevacizumab may add toxicity to chemotherapy and whether improve overall survival (OS) or not.

Comparative Effectiveness of Taxane-Containing Regimens for Treatment of HER2-Negative Metastatic Breast Cancer: A Network Meta-analysis

STUDY OBJECTIVES

To compare the effectiveness of different taxane-containing regimens and to identify the best strategy for the treatment of human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC).

DESIGN

Network meta-analysis of 20 randomized controlled trials (RCTs).

PATIENTS

A total of 6577 patients with HER2-negative MBC who received treatment (20 different regimens) with taxanes (paclitaxel [4267 patients] or docetaxel [2310 patients]).

MEASUREMENTS AND MAIN RESULTS

The PubMed, Embase, Cochrane Library, and ClinicalTrials.gov databases were searched (through March 2019) for RCTs that evaluated any taxane-containing regimens for the treatment of HER2-negative MBC. A network meta-analysis in a Bayesian framework was performed using the random-effects model. We compared the surface under the cumulative ranking (SUCRA) curve for each regimen. Overall, paclitaxel-based combinations were superior to paclitaxel alone in objective response rate (ORR) (odds ratio 1.60, 95% credible interval [CrI] 1.15-2.16) and overall survival (OS) (hazard ratio 1.08, 95% CrI 1.01-1.15). Docetaxel-based combinations were also superior to paclitaxel alone in ORR. Among the paclitaxel-based regimens, based on the results of SUCRA, paclitaxel + bevacizumab + capecitabine was likely to be the most efficacious in improving ORR, OS, and progression-free survival (PFS), whereas paclitaxel + gemcitabine was likely to be the most efficacious in 1-year OS rate. Among the docetaxel-based regimens, based on the results of SUCRA, docetaxel + gemcitabine was likely to be the most efficacious in improving PFS and OS.

CONCLUSION

These findings demonstrated that paclitaxel-based combinations can provide significant improvement in ORR and OS compared with paclitaxel alone. The regimens of paclitaxel + bevacizumab + capecitabine, docetaxel + gemcitabine, and paclitaxel + gemcitabine may be superior to other regimens for the treatment of HER2-negative MBC.

High baseline Tie1 level predicts poor survival in metastatic breast cancer

Background

Angiopoietin growth factors (Angs) regulate angiogenesis and lymphangiogenesis by binding to the endothelial Tie2 receptor. Ang2 expression is elevated in tissue hypoxia and inflammation, which also induce cleavage of the extracellular domain of the orphan Tie1 receptor. Here we have examined if the concentrations of Ang2 and the soluble extracellular domain of Tie1 in patient plasma are associated with the prognosis of patients with metastatic breast cancer.

Methods

Plasma Tie1 and Ang2 levels were measured in metastatic breast cancer patients treated in a phase II trial with a taxane-bevacizumab combination chemotherapy in the first-line treatment setting. They were analyzed before treatment, after 6 weeks and 6 months of treatment, and at the final study visit. Using the median concentrations as cutoffs, Tie1 and Ang2 data were dichotomized into low and high concentration groups. Additionally, we analyzed Tie1 concentrations in plasma from 10 healthy women participating in a breast cancer primary prevention study.

Results

Plasma samples were available from 58 (89%) of the 65 patients treated in the trial. The baseline Tie1 levels of the healthy controls were significantly lower than those of the metastatic patients (p < 0.001). The overall survival of the patients with a high baseline Tie1 level was significantly shorter (multivariate HR 3.07, 95% CI 1.39–6.79, p = 0.005). Additionally, the progression-free survival was shorter for patients with a high baseline Tie1 level (multivariate HR 3.78, 95% CI 1.57–9.09, p = 0.003). In contrast, the baseline Ang2 levels had no prognostic impact in a multivariate Cox proportional hazard regression analysis. The combined analysis of baseline Tie1 and Ang2 levels revealed that patients with both high Tie1 and high Ang2 baseline levels had a significantly shorter overall survival than the patients with low baseline levels of both markers (multivariate HR for overall survival 4.32, 95% CI 1.44–12.94, p = 0.009).

Conclusions

This is the first study to demonstrate the prognostic value of baseline Tie1 plasma concentration in patients with metastatic breast cancer. Combined with the results of the Ang2 analyses, the patients with both high Tie1 and Ang2 levels before treatment had the poorest survival.

Trial registration

Clinicaltrials.gov: NCT00979641, registration date 19-DEC-2008. The regional Ethics Committee: R08142M, registration date 18-NOV-2008.

Angiopoietin-2 Promotes Pathological Angiogenesis and Is a Therapeutic Target in Murine Nonalcoholic Fatty Liver Disease

Angiogenesis contributes to the development of nonalcoholic steatohepatitis (NASH) and promotes inflammation, fibrosis, and progression to hepatocellular carcinoma (HCC). Angiopoietin-2 (Ang-2) is a key regulator of angiogenesis. We aimed to investigate the role of Ang-2 and its potential as a therapeutic target in NASH using human samples, in vivo mouse models, and in vitro assays. Serum Ang-2 levels were determined in 104 obese patients undergoing bariatric surgery and concomitant liver biopsy. The effect of the Ang-2/Tie2 receptor inhibiting peptibody L1-10 was evaluated in the methionine-choline deficient (MCD) and streptozotocin-western diet nonalcoholic fatty liver disease mouse models, and in vitro on endothelial cells and bone marrow-derived macrophages. The hepatic vasculature was visualized with µCT scans and scanning electron microscopy of vascular casts. Serum Ang-2 levels were increased in patients with histological NASH compared with patients with simple steatosis and correlated with hepatic CD34 immunoreactivity as a marker of hepatic angiogenesis. Serum and hepatic Ang-2 levels were similarly increased in mice with steatohepatitis. Both preventive and therapeutic L1-10 treatment reduced hepatocyte ballooning and fibrosis in MCD diet-fed mice and was associated with reduced hepatic angiogenesis and normalization of the vascular micro-architecture. Liver-isolated endothelial cells and monocytes from MCD-fed L1-10-treated mice showed reduced expression of leukocyte adhesion and inflammatory markers, respectively, compared with cells from untreated MCD diet-fed mice. In the streptozotocin-western diet model, therapeutic Ang-2 inhibition was able to reverse NASH and attenuate HCC progression. In vitro, L1-10 treatment mitigated increased cytokine production in lipopolysaccharide-stimulated endothelial cells but not in macrophages. Conclusion: Our findings provide evidence for Ang-2 inhibition as a therapeutic strategy to target pathological angiogenesis in NASH.

Angiopoietin-1 and Angiopoietin-2 Inhibitors: Clinical Development

PURPOSE OF REVIEW

The purpose of this review is to discuss the current understanding of the Tie2-angiopoietin system and its role in tumor growth and metastasis. This review also focuses on preclinical and clinical data published to date that have evaluated Tie2-angiopoietin inhibition.

RECENT FINDINGS

Tie2 inhibition has shown significant promise in preclinical models, notable for decreased tumor burden and fewer sites of metastatic disease across various malignancies. However, data from human clinical trials have shown more mixed results. Trebananib, rebastanib, and MEDI3617 are the three Tie2-angiopoietin inhibitors that have been most widely evaluated in phase I and II trials. Further investigation into these therapies is ongoing. The Tie2-angiopoietin pathway continues to show promise in preclinical and some clinical trials, including studies on recurrent or metastatic breast and renal cell carcinomas. Further evaluation of these therapies, however, is warranted to better understand their optimal clinical utility.

Clinical and prognostic significance of circulating levels of angiopoietin-1 and angiopoietin-2 in hepatocellular carcinoma

Angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) play critical roles in angiogenesis in hepatocellular carcinoma (HCC). In addition, recent data suggest that Ang-1/Ang-2 are involved in regulating the immune response. The aim of our study was to explore the clinical prognostic significance of plasma Ang-1 and Ang-2 in HCC. We prospectively enrolled and collected data and blood samples from 767 HCC patients treated at MD Anderson Cancer Center between 2001 and 2014. Controls consisted of cirrhotic patients (n = 75) and healthy volunteers (n = 200). The cutoff value was the median level of each angiogenic factor. Overall survival (OS) was estimated by Kaplan–Meier curves and compared by the log-rank test. Higher plasma Ang-2 was significantly associated with advanced clinicopathologic features of advanced HCC and lower OS. Median OS was 61.8 months (95% confidence interval [CI], 45.1–78.5 months) for low Ang-2 compared with 28.5 months (95% CI, 24.8–32.1 months) for high Ang-2 (p < 0.001). In contrast, higher Ang-1 was associated with longer OS. Median OS was 37.2 months (95% CI, 31.0–43.4 months) for high Ang-1 compared with 26.2 months (95% CI, 22.2–30.3 months) for those with low Ang-1 (p = 0.043). In conclusion, our findings indicate that plasma Ang-1 and Ang-2 levels are potential diagnostic and prognostic biomarkers in HCC.

Tumor-associated macrophages in breast cancer: Innocent bystander or important player?

Tumor-associated macrophages (TAMs) are important tumor-promoting cells in the breast tumor microenvironment. Preclinically TAMs stimulate breast tumor progression, including tumor cell growth, invasion and metastasis. TAMs also induce resistance to multiple types of treatment in breast cancer models. The underlying mechanisms include: induction and maintenance of tumor-promoting phenotype in TAMs, inhibition of CD8+ T cell function, degradation of extracellular matrix, stimulation of angiogenesis and inhibition of phagocytosis. Several studies reported that high TAM infiltration of breast tumors is correlated with a worse patient prognosis. Based on these findings, macrophage-targeted treatment strategies have been developed and are currently being evaluated in clinical breast cancer trials. These strategies include: inhibition of macrophage recruitment, repolarization of TAMs to an antitumor phenotype, and enhancement of macrophage-mediated tumor cell killing or phagocytosis. This review summarizes the functional aspects of TAMs and the rationale and current evidence for TAMs as a therapeutic target in breast cancer.

Rhamnetin induces apoptosis in human breast cancer cells via the miR-34a/Notch-1 signaling pathway

The present study aimed to investigate whether rhamnetin induced apoptosis in human breast cancer cells and the underlying molecular mechanism of this anti cancer effect. The treatment of MCF-7 cells with rhamnetin was able to significantly inhibit cell proliferation and induce caspase-3/9 activity in a dose- and time-dependent manner, compared with untreated cells. In addition, treatment with rhamnetin was able to significantly promote the expression of p53 protein and microRNA (miR-)34a compared with untreated cells. The treatment with rhamnetin also suppressed the expression of Notch1 protein in MCF-7 cells compared with untreated cells. Subsequently, miR-24a expression was promoted in rhamnetin-treated MCF-7 cells using a miR-34a plasmid. The overexpression of miR-34a was able to significantly inhibit cell viability and induce caspase-3/9 activity in MCF-7 cells following treatment with rhamnetin. Furthermore, the overexpression of miR-34a was able to significantly promote the expression of p53 protein and miR-34a, and suppress the expression of Notch1 protein in rhamnetin-treated MCF-7 cells. Therefore, the results of the present study demonstrated that rhamnetin induced apoptosis in human breast cancer cells via the miR-34a/Notch-1 signaling pathway.

Phase 1b Study of Trebananib Plus Paclitaxel and Trastuzumab in Patients With HER2-Positive Locally Recurrent or Metastatic Breast Cancer

INTRODUCTION

Trebananib, a peptide-Fc fusion protein, blocks angiogenesis by inhibiting binding of angiopoietin-1/2 to the receptor tyrosine kinase Tie2. Trebananib plus trastuzumab and paclitaxel was evaluated in human epidermal growth factor receptor 2-positive breast cancer in an open-label phase 1b clinical study.

PATIENTS AND METHODS

Women with human epidermal growth factor receptor 2-positive breast cancer received weekly paclitaxel (80 mg/m²), trastuzumab (8 mg/m² then 6 mg/kg every 3 weeks), and intravenous trebananib (10 mg/kg or 30 mg/kg weekly) beginning week 2. The primary end point was the incidence of dose-limiting toxicities. Secondary end points included incidence of adverse events (AEs), pharmacokinetics, and tumor response (objective response and duration of response).

RESULTS

Forty women were enrolled; 2 experienced dose-limiting toxicities (grade 3 ocular transient ischemic attack [10 mg/kg cohort] and grade 3 elevation in γ-glutamyl transferase [30 mg/kg cohort]). The most common treatment-emergent AEs were peripheral edema (n = 28), diarrhea (n = 27), alopecia (n = 26), fatigue (n = 24), and nausea (n = 24). Maximum observed concentration and area under the concentration-time curve increased proportionally with the trebananib dose. Objective response was confirmed in 31 patients. In the 10 mg/kg cohort, 16 patients (80%) experienced partial response, and none experienced complete response. In the 30 mg/kg cohort, 12 patients (71%) experienced partial response and 3 (18%) experienced complete response. Median (95% confidence interval) duration of response in the 10 and 30 mg/kg cohorts was 12.6 (4.3-20.2) and 16.6 (8.2-not estimable) months, respectively.

CONCLUSION

This phase 1b study showed that trebananib was tolerated with manageable AEs at a dose up to 30 mg/kg weekly. Trebananib demonstrated anticancer activity, as indicated by objective response and duration of response.

Role of angiopoietins in mesothelioma progression

BACKGROUND AND OBJECTIVE

Anti-angiogenic treatment has been recently shown to be clinically beneficial for mesothelioma patients. Angiopoietins-1 and -2 are key regulators of tumor angiogenesis. Ang-1 is mainly known to promote angiogenesis and vessel stability, while Ang-2 could serve as an antagonist of Ang-1 causing vessel regression and destabilization or enhance angiogenesis in a context-dependent manner. We hypothesized that Ang-1 would promote and Ang2 would halt experimental mesothelioma by affecting tumor angiogenesis.

METHODS

To examine the effects of angiopoietins in mesothelioma angiogenesis and in vivo growth we constructed Ang-1 or Ang-2 overexpressing AE17 and AB1 mesothelioma cells and implanted them in the respective syngeneic animals. We also explored the clinical relevance of our observations using the human tumoral mRNAseq data available in the TCGA database.

RESULTS AND CONCLUSIONS

Ang-1 promotes mesothelioma angiogenesis and growth while the effect of Ang-2 is context-dependent. Low Ang-1 levels in human mesotheliomas are associated with the epitheloid subtype. Tumors of high Ang-1, or concurrent high Ang-2 and VEGF expression present high PECAM-1 and CDH5 expression, markers of vascularity and vascular stability, respectively. Our results highlight the importance of angiopoietins in mesothelioma pathophysiology and pave the way for the clinical development of novel anti-angiogenic strategies.

Risk of bleeding associated with antiangiogenic monoclonal antibodies bevacizumab and ramucirumab: a meta-analysis of 85 randomized controlled trials

Aim

Bevacizumab and ramucirumab are antiangiogenic monoclonal antibodies, which target vascular endothelial growth factor-A and vascular endothelial growth factor receptor-2, respectively, used in various cancers. Bleeding events have been described with these two agents. We conducted an up-to-date meta-analysis to determine the relative risk (RR) associated with the use of antiangiogenic monoclonal antibodies, bevacizumab and ramucirumab.

Methods

This meta-analysis of randomized controlled trials was performed after searching PubMed, American Society for Clinical Oncology Abstracts, European Society for Medical Oncology Abstracts, and the proceedings of major conferences for relevant clinical trials. RR and 95% CIs were calculated by random-effects or fixed-effects models for all-grade and high-grade bleeding events related to the angiogenesis inhibitors.

Results

Eighty-five randomized controlled trials were selected for the meta-analysis, covering 46,630 patients. The results showed that antiangiogenic monoclonal antibodies significantly increased the risk of all-grade (RR: 2.38, 95% CI: 2.09–2.71, p<0.00001) and high-grade (RR: 1.71, 95% CI: 1.48–1.97, p<0.00001) bleeding compared with control arms. In the subgroup analysis, bevacizumab significantly increased the risk of all-grade (RR: 2.73, 95% CI: 2.24–3.33, p<0.00001) and high-grade bleeding (RR: 1.98, 95% CI: 1.68–2.34, p<0.00001), but ramucirumab only increased the risk of all-grade bleeding (RR: 1.94, 95% CI: 1.76–2.13, p<0.00001) and no difference was observed for the risk of high-grade bleeding (RR: 1.04, 95% CI: 0.78–1.39, p=0.79) compared with the control group. For lung cancer patients, bevacizumab significantly increased the risk of all-grade (RR: 4.72, 95% CI: 1.99–11.19, p=0.0004) and high-grade pulmonary hemorrhage (RR: 3.97, 95% CI: 1.70–9.29, p=0.001), but no significant differences in the risk of all-grade (RR: 1.09, 95% CI: 0.76–1.57, p=0.64) and high-grade (RR: 1.22, 95% CI: 0.35–4.21, p=0.75) pulmonary hemorrhage were observed for ramucirumab. The increased risk of all-grade and high-grade bleeding was also observed in colorectal cancer or non-colorectal tumors and low-dose or high-dose angiogenesis inhibitors.

Conclusion

Antiangiogenic monoclonal antibodies are associated with a significant increase in the risk of all-grade and high-grade bleeding. Ramucirumab may be different from bevacizumab in terms of the risk of high-grade bleeding and the risk of all-grade and high-grade pulmonary hemorrhage in lung cancer patients.

Increased risk of adverse drug events secondary to bevacizumab treatment in patients with advanced or metastatic breast cancer: a meta-analysis of randomized controlled trials

Background

Several clinical trials have shown an increased risk of hypertension with bevacizumab when added to chemotherapy in different types of malignancy; however, the risks of other significant adverse events besides hypertension, specifically in breast cancer, have not been completely elucidated. This study was conducted with the aim, primarily, to assess the overall incidence and risk of common toxicities associated with bevacizumab in patients with advanced or metastatic breast cancer and, secondarily, to descriptively review study results concerning a potential correlation between bevacizumab-induced hypertension and its efficacy for breast cancer treatment.

Methods

We carried out a meta-analysis of relevant randomized controlled trials (RCTs) identified from a database search (Cochrane Library and PubMed) and, additionally, by reviewing previous reviews and meta-analyses. Overall incidence rates, odds ratios (ORs), and 95% confidence intervals (CIs) were assessed with the random- or fixed-effect models, depending on the level of heterogeneity across the included trials. The primary clinical outcomes were high-grade adverse events commonly reported with bevacizumab therapy.

Results

We included 6,260 patients with advanced-stage breast cancer from 12 RCTs in the meta-analysis. Five types of high-grade (Grade 3 or 4) adverse drug events were identified as being correlated with bevacizumab treatment versus alternative treatment with statistical significance: hypertension (OR 5.67, 95% CI 3.02–10.65), proteinuria (OR 10.09, 95% CI 4.79–21.27), bleeding (OR 3.45, 95% CI 2.25–5.30), cardiac toxicity (OR 2.15, 95% CI 1.29–3.59), and neutropenic fever (OR 1.51, 95% CI 1.15–2.00). The prognostic value of bevacizumab-induced hypertension for its antitumor efficacy among patients with breast cancer remains controversial, with mixed results presented in the five retrospective studies that were identified from our additional literature search.

Conclusion

The addition of bevacizumab to anticancer therapy was associated with a significant increase in the risk of high-grade adverse events, including hypertension, proteinuria, bleeding, cardiac toxicity, and neutropenic fever among patients with advanced-stage breast cancer. Although several retrospective studies suggested a predictive importance of hypertension secondary to bevacizumab therapy, the role of elevated blood pressure as a prognostic biomarker for its antitumor efficacy remains controversial, and further prospective trials are required to confirm such a correlation.

Targeting Tie-2/angiopoietin axis in experimental mesothelioma confers differential responses and raises predictive implications

Malignant pleural mesothelioma is resistant to currently used treatment. Angiopoieitn-1 directly promotes mesothelioma cell growth in a Tie-2-dependent fashion. Angiopoietin/Tie-2 axis may thus be valid targets for therapeutic interventions against mesothelioma. We hypothesized that a soluble angiopoietin inhibitor (Murine Tek-deltaFc) would halt mesothelioma progression in vivo by enhancing mesothelioma cell proliferation and inhibiting tumor angiogenesis. Our hypothesis was challenged on two syngeneic mesothelioma in vivo models (AB1 cells-Balb/c mice and AE17 cells-C57BL/6 mice. Even though both mesothelioma cell lines express the Angiopoietin-1/-2 and Tie-2, murine Tek-deltaFc hampered AB1 but not AE17 mesothelioma growth in vivo by enhancing tumor cell apoptosis and limiting tumor angiogenesis. Neither angiopoietins (Angs)-1 and -2 nor the inhibitor affected mesothelioma cell growth in vitro. AB1 (responding) tumors were more vascularized and displayed higher endothelial Tie-2 and lower tumor Ang-1 expression than the (non-responding) AE17 tumors. Angiopoietins-1 and -2 are expressed in tumors and pleural cavity of mesothelioma patients demonstrating the clinical relevance of our experimental observations. In conclusion, disrupting Ang-Tie-2 signaling limits mesothelioma angiogenesis and halts tumor progression. Tumor vascularity, endothelial Tie-2 expression and tumor Ang-1 expression may predict mesothelioma response to Tek-deltaFc.

Peptibodies: An elegant solution for a long-standing problem

Chimeric proteins composed of a biologically active peptide and a fragment crystallizable (Fc) domain of immunoglobulin G (IgG) are known as peptibodies. They present an extended half-life due to neonatal Fc receptor (FcRn) salvage pathway, a decreased renal clearance rate owing to its increased size (≈70 kDa) and, depending on the peptide used in the design of the peptibody, an active-targeting moiety. Also, the peptides therapeutic activity is boosted by the number of peptides in the fusion protein (at least two peptides) and to some peptides' alterations. Peptibodies are mainly obtained through recombinant DNA technology. However, to improve peptide properties, "unnatural" changes have been introduced to the original peptides' sequence, for instance, the incorporation of D- or non-natural amino acid residues or even cyclization thus, limiting the application of genetic engineering in the production of peptibodies, since these peptides must be obtained via chemical synthesis. This constrains prompted the development of new methods for conjugation of peptides to Fc domains. Another challenge, subject of intense research, relates to the large-scale production of such peptibodies using these new techniques, which can be minimized by their proved value. To date, two peptibodies, romiplostim and dulaglutide, have been approved and stay as the standard of care in their areas of action. Furthermore, a considerable number of peptibodies are currently in preclinical and clinical development.

Phase 2 and biomarker study of trebananib, an angiopoietin-blocking peptibody, with and without bevacizumab for patients with recurrent glioblastoma

BACKGROUND

Angiopoietins contribute to tumor angiogenesis and may be upregulated as a compensatory factor after vascular endothelial growth factor (VEGF) blockade. The authors performed a phase 2 and biomarker study to evaluate trebananib, an angiopoietin 1 and angiopoietin 2 blocking peptibody, with and without bevacizumab in patients with recurrent glioblastoma.

METHODS

Forty-eight patients who had bevacizumab-naive, recurrent glioblastoma were treated with trebananib (30 mg/kg weekly) as single agent (n = 11) or combined with bevacizumab (n = 37). The primary endpoint was 6-month progression-free survival rate as determined by investigator review. Circulating biomarker levels were assessed before and after study therapy.

RESULTS

Trebananib was well tolerated as monotherapy and did not enhance bevacizumab-associated toxicity. Trebananib had no single-agent activity, and all treated patients exhibited progressive disease within 2 months. The 6-month progression-free survival rate for trebananib plus bevacizumab was 24.3% (95% confidence interval [CI], 12.1%-38.8%); whereas the median overall survival was 9.5 months (95% CI, 7.5-4.7 months), and the 12-month overall survival rate was 37.8% (95% CI, 22.6%-53.0%). Baseline and post-treatment changes in circulating vascular VEGF and interleukin-8 levels were correlated with survival among patients who received trebananib plus bevacizumab.

CONCLUSIONS

Angiopoietin 1 and angiopoietin 2 inhibition with trebananib was ineffective as monotherapy and did not enhance the ability of VEGF blockade with bevacizumab to improve the outcomes of patients with recurrent glioblastoma. Cancer 2018;124:1438-48. © 2017 American Cancer Society.

First-in-Human Phase I Study of Single-agent Vanucizumab, A First-in-Class Bispecific Anti-Angiopoietin-2/Anti-VEGF-A Antibody, in Adult Patients with Advanced Solid Tumors

Purpose: Vanucizumab is an investigational antiangiogenic, first-in-class, bispecific mAb targeting VEGF-A and angiopoietin-2 (Ang-2). This first-in-human study evaluated the safety, pharmacokinetics, pharmacodynamics, and antitumor activity of vanucizumab in adults with advanced solid tumors refractory to standard therapies.Experimental Design: Patients received escalating biweekly (3-30 mg/kg) or weekly (10-30 mg/kg) intravenous doses guided by a Bayesian logistic regression model with overdose control.Results: Forty-two patients were treated. One dose-limiting toxicity, a fatal pulmonary hemorrhage from a large centrally located mediastinal mass judged possibly related to vanucizumab, occurred with the 19 mg/kg biweekly dose. Arterial hypertension (59.5%), asthenia (42.9%), and headache (31%) were the most common toxicities. Seventeen (41%) patients experienced treatment-related grade ≥3 toxicities. Toxicity was generally higher with weekly than biweekly dosing. A MTD of vanucizumab was not reached in either schedule. Pharmacokinetics were dose-linear with an elimination half-life of 6-9 days. All patients had reduced plasma levels of free VEGF-A and Ang-2; most had reductions in K^TRANS (measured by dynamic contrast-enhanced MRI). Two patients (renal cell and colon cancer) treated with 30 mg/kg achieved confirmed partial responses. Ten patients were without disease progression for ≥6 months. A flat-fixed 2,000 mg biweekly dose (phamacokinetically equivalent to 30 mg/kg biweekly) was recommended for further investigation.Conclusions: Biweekly vanucizumab had an acceptable safety and tolerability profile consistent with single-agent use of selective inhibitors of the VEGF-A and Ang/Tie2 pathway. Vanucizumab modulated its angiogenic targets, impacted tumor vascularity, and demonstrated encouraging antitumor activity in this heterogeneous population. Clin Cancer Res; 24(7); 1536-45. ©2017 AACR.

Pediatric Phase I Trial and Pharmacokinetic Study of Trebananib in Relapsed Solid Tumors, Including Primary Tumors of the Central Nervous System ADVL1115: A Children's Oncology Group Phase I Consortium Report

Purpose: Trebananib is a first-in-class antiangiogenic peptibody (peptide-Fc fusion protein) that inhibits Angiopoietin 1 and 2. A pediatric phase 1 trial was performed to define trebananib dose-limiting toxicities (DLT), recommended phase 2 dose (RP2D), and pharmacokinetics (PK).Experimental Design: Trebananib was administered by weekly infusion. Three dose levels (10, 15, or 30 mg/kg/dose) were evaluated using a rolling-six design. Part 2 evaluated a cohort of subjects with primary central nervous system (CNS) tumors. Pharmacokinetic sampling and analysis of peripheral blood biomarkers was performed during the first 4 weeks. Response was evaluated after 8 weeks. Correlative studies included angiogenic protein expression and DCE-MRI.Results: Thirty-seven subjects were enrolled (31 evaluable for toxicity) with median age 12 years (range, 2 to 21). Two of 19 evaluable non-CNS subjects developed DLT at the 30 mg/kg dose level, including venous thrombosis and pleural effusion. In the CNS cohort, 3/12 subjects developed DLT, including decreased platelet count, transient ischemic attack, and cerebral edema with headache and hydrocephalus. Other grade 3 or 4 toxicities included lymphopenia (n = 4), anemia, thrombocytopenia, neutropenia, vomiting, and hypertension (n = 1 each). Response included stable disease in 7 subjects, no partial or complete responses. Two subjects continued study treatment with prolonged stable disease for 18 cycles (neuroblastoma) and 26 cycles (anaplastic astrocytoma). Pharmacokinetics appeared linear over 3 dose levels. Correlative studies demonstrated increased PlGF and sVCAM-1, but no change in endoglin or perfusion by DCE-MRI.Conclusions: Trebananib was well tolerated in pediatric patients with recurrent or refractory solid or CNS tumors. RP2D is 30 mg/kg. Clin Cancer Res; 23(20); 6062-9. ©2017 AACR.

Clinical results of randomized trials and 'real-world' data exploring the impact of Bevacizumab for breast cancer: opportunities for clinical practice and perspectives for research

INTRODUCTION

Angiogenesis plays a fundamental role in breast cancer (BC) growth, progression and metastatic spread. After the promising introduction of bevacizumab for the treatment of advanced BC, the initial enthusiasm decreased when the FDA withdrew its approval in 2011. Nevertheless, several clinical studies exploring the role of bevacizumab have been subsequently published. Areas covered: The aim of this study is to review the available clinical trials exploring the potential effectiveness of bevacizumab in BC, regardless of the disease setting. Expert opinion: Even if the evidence suggests that bevacizumab must be ruled out from the HER2-positive and adjuvant setting, bevacizumab's benefit remains uncertain in the neoadjuvant setting and in the advanced treatment of HER2-negative patients. In the first setting, the addition of bevacizumab to chemotherapy increased the pathological complete response (pCR) rate in most clinical trials. However, the current absence of evidence that pCR is a trial-level surrogate for survival requires waiting for long-term results. In the advanced setting, all trials showed a benefit in progression-free survival, but not in overall survival, highlighting an increase of adverse events. The lack of predictors of response represents the main unmet need in which future clinical research will undoubtedly invest.

Angiopoietin pathway gene expression associated with poor breast cancer survival

PURPOSE

Angiogenesis is one of the hallmarks of cancer and is essential for cancer progression and metastasis. However, clinical trials with vascular endothelial growth factor (VEGF) pathway inhibitors have failed to show overall survival benefit in breast cancer. Targeted therapy against the angiopoietin pathway, a downstream angiogenesis cascade, could be effective in breast cancer. This study investigates the association of angiopoietin pathway gene expression with breast cancer survival using a "big data" approach employing RNA sequencing data from The Cancer Genome Atlas (TCGA).

METHODS

A total of 888 patients with adequate gene expression, disease-free survival (DFS), and overall survival (OS) data were selected for analysis. DFS and OS were calculated for patients with high and low expression of angiopoietin and VEGF pathway genes using TCGA data. Gene-specific thresholds to dichotomize patients into high and low expression were determined and survival plots were generated.

RESULTS

The TCGA cohort was representative of national breast cancer patients with respect to stage, pathology, and survival. High Ang2 gene expression was associated with not only decreased DFS (p = 0.05), but also decreased OS (p < 0.05). High co-expression of Ang2 and its receptor Tie2 was associated with both decreased DFS and OS (p < 0.05). There was strong correlation between angiopoietin and VEGF pathway genes. While high expression of VEGFA alone was not associated with survival, high co-expression with Ang2 was associated with decreased OS.

CONCLUSIONS

This study validates TCGA as a representative database providing genomic data and survival outcomes in breast cancer. Our TCGA data support the angiopoietin pathway as a key mediator in the pathologic angiogenic switch in breast cancer.

Disrupting Tumor Angiogenesis and "the Hunger Games" for Breast Cancer

Angiogenesis, one of the hallmarks of cancers, has become an attractive target for cancer therapy since decades ago. It is broadly thought that upregulation of angiogenesis is involved in tumor progression and metastasis. Though tumor vessels are tortuous, disorganized, and leaky, they deliver oxygen and nutrients for tumor development. Based on this knowledge, many kinds of drugs targeting angiogenesis pathways have been developed, such as bevacizumab. However, the clinical outcomes of anti-angiogenesis therapies are moderate in metastatic breast cancer as well as in metastatic colorectal cancer and non-small cell lung cancer, even combined with traditional chemotherapy. In this chapter, the morphologic angiogenesis patterns and the key molecular pathways regulating angiogenesis are elaborated. The FDA-approved anti-angiogenesis drugs and current challenges of anti-angiogenesis therapy are described. The strategies to overcome the barriers will also be elucidated.

Molecular Pathways: Deciphering Mechanisms of Resistance to Macrophage-Targeted Therapies

Tumor-associated macrophages (TAMs) are a major cellular component of numerous tumor types. TAM-targeted therapies include depletion strategies, inhibiting their effector functions or reprogramming toward an antitumorigenic phenotype, with varying degrees of efficacy. Here, we review preclinical and clinical strategies to target macrophages in cancer and discuss potential explanations for why some strategies are effective while other approaches have shown limited success. Clin Cancer Res; 23(4); 876-84. ©2016 AACR.

Aflibercept and Ang1 supplementation improve neoadjuvant or adjuvant chemotherapy in a preclinical model of resectable breast cancer

Phase III clinical trials evaluating bevacizumab (an antibody to the angiogenic ligand, VEGF-A) in breast cancer have found improved responses in the presurgical neoadjuvant setting but no benefits in the postsurgical adjuvant setting. The objective of this study was to evaluate alternative antiangiogenic therapies, which target multiple VEGF family members or differentially modulate the Angiopoietin/Tie2 pathway, in a mouse model of resectable triple-negative breast cancer (TNBC). Neoadjuvant therapy experiments involved treating established orthotopic xenografts of an aggressive metastatic variant of the MDA-MB-231 human TNBC cell line, LM2-4. Adjuvant therapies were given after primary tumor resections to treat postsurgical regrowths and distant metastases. Aflibercept (‘VEGF Trap’, which neutralizes VEGF-A, VEGF-B and PlGF) showed greater efficacy than nesvacumab (an anti-Ang2 antibody) as an add-on to neoadjuvant/adjuvant chemotherapy. Concurrent inhibition of Ang1 and Ang2 signaling (through an antagonistic anti-Tie2 antibody) was not more efficacious than selective Ang2 inhibition. In contrast, short-term perioperative BowAng1 (a recombinant Ang1 variant) improved the efficacy of adjuvant chemotherapy. In conclusion, concurrent VEGF pathway inhibition is more likely than Ang/Tie2 pathway inhibition (e.g., anti-Ang2, anti-Ang2/Ang1, anti-Tie2) to improve neoadjuvant/adjuvant chemotherapies for TNBC. Short-term perioperative Ang1 supplementation may also have therapeutic potential in conjunction with adjuvant chemotherapy for TNBC.

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.

Efficacy and safety of adding an agent to bevacizumab/taxane regimens for the first-line treatment of Her2-negative patients with locally recurrent or metastatic breast cancer: results from seven randomized controlled trials

Background

The combined therapy of bevacizumab (BEV) with taxane (paclitaxel or docetaxel) has shown an improvement on progression-free survival (PFS) and objective remission in Her2-negative patients with locally recurrent or metastatic breast cancer (LR/MBC). However, there was no benefit in overall survival (OS). The aim of this study was to evaluate the efficacy and safety of adding an agent to the BEV/taxane regimens for the treatment of Her2-negative patients with LR/MBC in a first-line setting.

Materials and methods

We searched PubMed, Web of Science, EMBASE, EBSCO, and the Cochrane Library databases for eligible trials. A meta-analysis was performed using Review Manager 5.0 freeware package. We calculated the hazard ratio (HR) for PFS and OS. The odds ratio (OR) was used to calculate objective response rate (ORR) and grade 3/4 drug-related adverse events. The heterogeneity of study outcomes was calculated by the χ² test or I² statistics.

Results

A total of 1,124 patients from seven randomized controlled trials were analyzed. Our meta-analysis showed that the ORR was significantly improved in the BEV/taxane-based triplet group when compared with the BEV/taxane-based doublet group (OR =1.31, 95% confidence interval [CI]: 1.03–1.67, P=0.03). A subset analysis showed that a similar result was achieved in the triplet group in which a cytotoxic agent was added (OR =1.46, 95% CI: 1.09–1.95, P=0.01). However, the PFS and OS had no statistically significant differences between the two groups (HR =0.87, 95% CI: 0.68–1.13, P=0.31; HR =0.98, 95% CI: 0.82–1.16, P=0.78, respectively). Regarding safety, thromboembolic events, fatigue, and diarrhea (all $grade 3) were more frequently observed in the BEV/taxane-based triplet group (OR =3.8, 95% CI: 1.86–7.79, P=0.0003; OR =1.55, 95% CI: 1.05–2.27, P=0.03; OR =2.1, 95% CI: 1.29–3.41, P=0.003, respectively). Other toxic effects had no statistically significant differences between the two groups.

Conclusion

Our results showed that adding an agent to BEV/taxane treatment regimens did not significantly improve PFS and prolong OS, except for conferring a significant advantage toward improved ORR in the first-line therapy for Her2-negative patients with LR/MBC. However, its side effects are predictable and manageable.

Cancer Tills the Premetastatic Field: Mechanistic Basis and Clinical Implications

A growing body of work has shown that cancer metastasis is not a random spontaneous event; rather, it is the culmination of a cascade of priming steps through which a subpopulation of the tumor cells acquires invasive traits while readying a permissive environment, termed the "premetastatic niche," in which distant metastases can occur. Signals from the primary tumor mobilize and adapt immune cells as well as directly communicating with distant niche cells to induce a broad spectrum of adaptations in target organs, including the induction of angiogenesis, inflammation, extracellular matrix remodeling, and metabolic reprogramming. Together, these interactions facilitate the formation of a premetastatic niche composed of a variable mix of resident and recruited immune cells, endothelial cells, and stromal cells connected through a complex signaling network that we are only beginning to understand. Here, we summarize the latest findings on how cancer induces and guides the formation of this premetastatic niche as well as potential prognostic markers and therapeutic targets that may lead to a better understanding and effective treatment of metastatic disease. Clin Cancer Res; 22(15); 3725-33. ©2016 AACR.

The dual role of tumor lymphatic vessels in dissemination of metastases and immune response development

Lymphatic vasculature plays a crucial role in the immune response, enabling transport of dendritic cells (DCs) and antigens (Ags) into the lymph nodes. Unfortunately, the lymphatic system has also a negative role in the progression of cancer diseases, by facilitating the metastatic spread of many carcinomas to the draining lymph nodes. The lymphatics can promote antitumor immune response as well as tumor tolerance. Here, we review the role of lymphatic endothelial cells (LECs) in tumor progression and immunity and mechanism of action in the newest anti-lymphatic therapies, including photodynamic therapy (PDT).

Fcγ1 fragment of IgG1 as a powerful affinity tag in recombinant Fc-fusion proteins: immunological, biochemical and therapeutic properties

Affinity tags are vital tools for the production of high-throughput recombinant proteins. Several affinity tags, such as the hexahistidine tag, maltose-binding protein, streptavidin-binding peptide tag, calmodulin-binding peptide, c-Myc tag, glutathione S-transferase and FLAG tag, have been introduced for recombinant protein production. The fragment crystallizable (Fc) domain of the IgG1 antibody is one of the useful affinity tags that can facilitate detection, purification and localization of proteins and can improve the immunogenicity, modulatory effects, physicochemical and pharmaceutical properties of proteins. Fcγ recombinant forms a group of recombinant proteins called Fc-fusion proteins (FFPs). FFPs are widely used in drug discovery, drug delivery, vaccine design and experimental research on receptor-ligand interactions. These fusion proteins have become successful alternatives to monoclonal antibodies for drug developments. In this review, the physicochemical, biochemical, immunological, pharmaceutical and therapeutic properties of recombinant FFPs were discussed as a new generation of bioengineering strategies.