Pharmacodynamic and pharmacogenetic angiogenesis-related markers of first-line FOLFOXIRI plus bevacizumab schedule in metastatic colorectal cancer

Investigation of Vascular Endothelial Growth Factor Polymorphisms on Risk, Metastasis, Laterality, and Prognosis of Colorectal Cancer in Turkish Subjects

Objectives: Tumor angiogenesis is known to support the spread and invasion of tumor cells, allow distant organ metastasis, resulting in worse prognosis and mortality. Since vascular endothelial growth factor-A (VEGF-A) is the major regulator of angiogenesis, in the present study, the associations of VEGF-A +405G>C and -460C>T polymorphisms with risk, primary tumor location, prognosis, and metastasis of colorectal cancer (CRC) were investigated in Turkish subjects. Material and Methods: A total of 153 subjects consisting of 74 controls and 79 CRC diagnosed patients were included in the study. VEGF-A +405G>C and -460C>T polymorphisms were analyzed using Agena MassARRAY platform. Results: VEGF +405GC+CC genotypes were found to be significantly associated with left colon cancer (unadjusted odds ratio [OR] = 5.208 confidence interval [95% CI]: 1.064-25.496, p = 0.04). VEGF -460TT and CT+TT genotypes were associated with reduced liver metastasis risk (OR = 0.080 95% CI: 0.009-0.689 p = 0.02 and OR = 0.191 95% CI: 0.039-0.925, p = 0.04, respectively). Patients with VEGF +405GG genotype showed longer progression-free survival as a response to bevacizumab treatment (Log rank = 6.92, p = 0.03). Conclusion: According to our results, VEGF +405G>C and -460C>T polymorphisms were found to be associated with CRC prognosis, sidedness, and metastasis. Our findings should be conducted in further studies.

Neutralization of the induced VEGF-A potentiates the therapeutic effect of an anti-VEGFR2 antibody on gastric cancer in vivo

The vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) axis is an essential regulator of angiogenesis and important therapeutic target in cancer. Ramucirumab is an anti-VEGFR2 monoclonal antibody used for the treatment of several cancers. Increased circulating VEGF-A levels after ramucirumab administration are associated with a worse prognosis, suggesting that excess VEGF-A induced by ramucirumab negatively affects treatment efficacy and that neutralizing VEGF-A may improve treatment outcomes. Here, we evaluated the effect of combination treatment with an anti-VEGFR2 antibody and anti-VEGF-A antibody on gastric tumor progression and normal tissues using a preclinical BALB/c-nu/nu mouse xenograft model. After anti-VEGFR2 antibody treatment in mice, a significant increase in plasma VEGF-A levels was observed, mirroring the clinical response. The elevated VEGF-A was host-derived. Anti-VEGF-A antibody co-administration enhanced the anti-tumor effect of the anti-VEGFR2-antibody without exacerbating the toxicity. Mechanistically, the combination treatment induced intra-tumor molecular changes closely related to angiogenesis inhibition and abolished the gene expression changes specifically induced by anti-VEGFR2 antibody treatment alone. We particularly identified the dual treatment-selective downregulation of ZEB1 expression, which was critical for gastric cancer cell proliferation. These data indicate that the dual blockade of VEGF-A and VEGFR2 is a rational strategy to ensure the anti-tumor effect of angiogenesis-targeting therapy.

Are All Anti-Angiogenic Drugs the Same in the Treatment of Second-Line Metastatic Colorectal Cancer? Expert Opinion on Clinical Practice

Targeting tumor-driven angiogenesis is an effective strategy in the management of metastatic colorectal cancer (mCRC); however, the choice of second-line therapy is complicated by the availability of several drugs, the occurrence of resistance and the lack of validated prognostic and predictive biomarkers. This review examines the use of angiogenesis-targeted therapies for the second-line management of mCRC patients. Mechanisms of resistance and anti-placental growth factor agents are discussed, and the role of aflibercept, a recombinant fusion protein consisting of portions of human vascular endothelial growth factor receptor (VEGFR)-1 and VEGFR-2, is highlighted. The novel mechanism of action of aflibercept makes it a useful second-line agent in mCRC patients progressing after oxaliplatin-based chemotherapy, as well as in those with resistance after bevacizumab.

Protocol of the EFFORT study: a prospective study of FOLFIRI plus aflibercept as second-line treatment after progression on FOLFOXIRI plus bevacizumab or during maintenance treatment in patients with unresectable/metastatic colorectal cancer

Background

FOLFOXIRI plus bevacizumab is used as a first-line therapy for patients with unresectable or metastatic colorectal cancer. However, there are no clear recommendations for second-line therapy after FOLFOXIRI plus bevacizumab combination. Here, we describe our planning for the EFFORT study to investigate whether FOLFIRI plus aflibercept has efficacy following FOLFOXIRI plus bevacizumab for mCRC.

Methods

EFFORT is an open-label, multicenter, single arm phase II study to evaluate whether a FOLFIRI plus aflibercept has efficacy following FOLFOXIRI plus bevacizumab for mCRC. Patients with unresectable or metastatic colorectal cancer who received FOLFOXIRI plus bevacizumab as a first-line therapy will receive aflibercept and FOLFIRI (aflibercept 4 mg/kg, irinotecan 150 mg/m² IV over 90 min, with levofolinate 200 mg/m² IV over 2 h, followed by fluorouracil 400 mg/m² bolus and fluorouracil 2400 mg/m² continuous infusion over 46 h) every 2 weeks on day 1 of each cycle. The primary endpoint is progression-free survival (PFS). To achieve 80% power to show a significant response benefit with a one-sided alpha level of 0.10, assuming a threshold progression-free survival of 3 months and an expected value of at least 5.4 months, we estimated that 32 patients are necessary. Secondary endpoints include overall survival, overall response rate, safety, and exploratory biomarker analysis for differentiating anti-VEGF drug in 2nd-line chemotherapy for unresectable or metastatic colorectal cancer.

Discussion

This is the first study to investigate whether FOLFIRI plus aflibercept has efficacy following FOLFOXIRI plus bevacizumab for unresectable or metastatic colorectal cancer. Switching to a different type of anti-VEGF drug in second-line therapy after FOLFOXIRI plus bevacizumab appears to be an attractive treatment strategy when considering survival benefit. It is expected that this phase II study will prove the efficacy of this strategy and that a biomarker for drug selection will be discovered.

Trial registration

Japan Registry of Clinical Trials jRCTs071190003. Registered April 18, 2019.

Circulating Biomarkers for Tumor Angiogenesis: Where Are We?

BACKGROUND

In recent years, several anti-angiogenic drugs have been developed and their addition to standard treatment has been associated with clinical benefits. However, the response to anti-angiogenic therapy is characterized by considerable variability. In this context, the development of dynamic non-invasive biomarkers would be helpful to elucidate the emergence of anti-angiogenic resistance as well as to correctly address the treatment.

OBJECTIVES

The purpose of this review is to describe current reports on circulating diagnostic and prognostic biomarkers related to angiogenesis. We further discuss how this non-invasive strategy could improve the monitoring of tumor treatment and help clinical strategy.

RESULTS

We discuss the latest evidence in the literature regarding circulating anti-angiogenic markers. Besides growth factor proteins, different circulating miRNAs could exert a pro- or anti-angiogenic activity so as to represent suitable candidates for a non-invasive strategy. Recent reports indicate that tumor-derived exosomes, which are small membrane vesicles abundant in biological fluids, also have an impact on vascular remodeling.

CONCLUSION

Numerous circulating biomarkers related to angiogenesis have been recently identified. Their use will allow identifying patients who are more likely to benefit from a specific anti-angiogenic treatment, as well as detecting those who will develop resistance and/or adverse effects. Nonetheless, further studies are required to elucidate the role of these biomarkers in clinical settings.

Therapeutic Targeting of the Colorectal Tumor Stroma

Colorectal tumors have been classified based on histologic factors, genetic factors, and consensus molecular subtypes, all of which affect the tumor microenvironment. Elements of the tumor microenvironment serve as therapeutic targets and might be used as prognostic factors. For example, immune checkpoint inhibitors are used to treat tumors with microsatellite instability, and anti-angiogenic agents may be used in combination with other drugs to slow or inhibit tumor growth. We review the features of the colorectal tumor stroma that are associated with patient outcomes and discuss potential therapeutic agents that target these features.

Impact of Prior Bevacizumab Treatment on VEGF-A and PlGF Levels and Outcome Following Second-Line Aflibercept Treatment: Biomarker Post Hoc Analysis of the VELOUR Trial

PURPOSE

Aflibercept is a targeted anti-VEGF therapy used to treat patients with metastatic colorectal cancer (mCRC) following progression on oxaliplatin-based regimens. This post hoc study evaluated the effect of prior bevacizumab treatment and growth factor levels on patient outcomes associated with aflibercept in the VELOUR phase III trial.

EXPERIMENTAL DESIGN

Baseline biomarker plasma concentrations were measured using a bead-based multiplex assay. Patients were grouped according to prior bevacizumab treatment, second-line treatment, and serum biomarker concentrations, and analyzed for overall survival (OS) and progression-free survival (PFS).

RESULTS

Plasma samples were available for 553 patients (placebo n = 265; aflibercept n = 288), of which 169 had received prior bevacizumab. Nine biomarkers implicated in angiogenesis or bevacizumab resistance correlated with prior bevacizumab therapy. VEGF-A and placental growth factor (PlGF) were the most significantly increased in patients who had received prior bevacizumab compared with those who had not received prior bevacizumab. In the placebo group, patients with high VEGF-A (>144 pg/mL) levels at baseline had worse OS and PFS compared with patients with lower levels at baseline (9.6 vs. 12.9 months). This was also seen in patients who received placebo and had high baseline PlGF (>8 pg/mL; 9.7 vs. 11.7 months). In the aflibercept group, prolonged OS and PFS were observed regardless of baseline VEGF-A or PlGF levels.

CONCLUSIONS

High VEGF-A and PlGF serum levels may underlie development of resistance to bevacizumab in patients with mCRC. Aflibercept retains its activity regardless of baseline VEGF-A and PlGF levels and may be an effective second-line treatment for patients with bevacizumab-induced resistance.

Thrombospondin-1 promotes tumor progression in cutaneous T-cell lymphoma via CD47

CD47 is highly expressed on various hematopoietic malignancies, and enables cancer cells to avoid immunosurveillance. Its ligand, thromobospondin-1 (TSP-1) is a multifunctional protein, and CD47/TSP-1 interactions promote tumor progression in various malignancies. In this study, we investigated roles of TSP-1 and CD47 in cutaneous T-cell lymphoma (CTCL). Flow cytometric analysis and immunohistochemistry showed that CTCL tumor cells and CTCL cell lines (Hut78, HH, and MyLa cells) overexpressed CD47 compared with normal CD4⁺ T cells. Overexpression of CD47 was partially induced by high c-Myc expression in CTCL tumor cells. TSP-1 mRNA expression levels in CTCL lesional skin were higher than those in normal skin and correlated with increased risk of disease-related death. Moreover, TSP-1 was expressed on CTCL tumor cells by immunohistochemistry. Serum soluble TSP-1 levels in patients with Sézary syndrome were significantly elevated. TSP-1 promotes proliferation and survival of CTCL tumor cells, which is inhibited by anti-CD47 neutralizing antibody or CD47 knockdown. Stimulation with TSP-1 also induces cell migration and in vivo growth. These effects were mediated by phosphorylation of ERK1/2 and AKT and expression of survivin. Collectively, our findings prompt a novel therapeutic approach to CTCL based on discovery that CD47/TSP-1 interactions play important roles in progression of CTCL.

The role of PIGF blockade in the treatment of colorectal cancer: overcoming the pitfalls

Introduction: In colorectal cancer, anti-VEGF agents have demonstrated a survival benefit when combined with chemotherapy. However, development of resistance is very common. One of the mechanisms is due not to a failure in the VEGFR blockade, but rather to development of compensatory mechanisms of resistance, such as hypoxia-triggered upregulation of other proangiogenic factors, like placental growth factor (PlGF).Areas covered: This article summarizes the fundamental role of PlGF in the development of resistance to antiangiogenic treatment as well as the efficacy of aflibercept, ramucirumab, and regorafenib.Expert opinion: Aflibercept functions as a soluble decoy receptor precluding VEGFs and PlGF from binding to native VEGFR, and therefore preventing the emergence of resistance. Bevacizumab limits its function to preventing the interaction between VEGF-A and VEGFR. In combination with FOLFIRI (VELOUR trial), aflibercept improves survival in patients with metastatic CRC who are resistant or have progressed to oxaliplatin-based chemotherapy. Ramucirumab, a fully humanized immunoglobulin G1 (IgG-1) monoclonal antibody and regorafenib, a multikinase inhibitor, have significant improvement for overall survival as well as for progression-free survival in chemotherapy refractory settings.

Efficacy and Safety of Aflibercept in Combination With Chemotherapy Beyond Second-Line Therapy in Metastatic Colorectal Carcinoma Patients: An AGEO Multicenter Study

BACKGROUND

Although no data have been reported beyond second-line therapy, aflibercept is approved in this setting in many countries. We conducted a multicenter study to analyze the efficacy and safety of a aflibercept-chemotherapy regimen beyond second-line therapy in patients with metastatic colorectal cancer.

PATIENTS AND METHODS

Metastatic colorectal cancer patients treated with aflibercept beyond second-line therapy were included. Objective response rate, overall survival (OS), and progression-free survival (PFS) were assessed.

RESULTS

A total of 130 patients were included. Median OS and PFS were 7.6 months (95% confidence interval, 6.2-9.3) and 3.3 months (95% confidence interval, 2.7-3.8), respectively. The best response rates were partial response 6.9%, stable disease 38.5%, progressive disease 42.5%, and not evaluable 12%. According to whether patients received previous FOLFIRI (leucovorin, 5-fluorouracil, irinotecan, and oxaliplatin)-bevacizumab or not, OS was 7.7 and 8.1 months (P = .31), and PFS was 2.9 and 3.9 months (P = .02), respectively. Interestingly, PFS and OS were both significantly improved by 4% and 5% per month, respectively, without antiangiogenic treatment before the initiation of the aflibercept regimen. The negative effect of prior FOLFIRI-bevacizumab or shorter time since last bevacizumab was maintained in multivariate analysis for both OS and PFS.

CONCLUSION

The aflibercept-chemotherapy regimen is a therapeutic option in patients with chemorefractory disease beyond second-line therapy, in particular in patients with an antiangiogenic-free interval.

Protein array profiling of circulating angiogenesis-related factors during bevacizumab containing treatment in metastatic colorectal cancer

BACKGROUND

Prolonged angiogenesis inhibition may improve treatment outcome in metastatic colorectal cancer (mCRC) patients. However, due to the complexity of the angiogenic pathways there is a lack of valid predictive biomarkers for anti-angiogenic agents. Here, we describe and optimize a procedure for simultaneous dynamic profiling of multiple angiogenesis related proteins in patient serum to explore associations with the response and acquired resistance to anti-angiogenic therapy.

MATERIALS AND METHODS

Patients (n=22) were selected from a clinical trial investigating maintenance treatment with bevacizumab alone after response to induction chemotherapy + bevacizumab in mCRC. Serum samples were analysed for 55 unique angiogenesis related proteins using a commercial proteome profiler array and a publicly available image analysis program for quantification. Samples were collected at baseline before induction treatment start, at start of maintenance treatment, and at end of treatment after tumour progression.

MAIN RESULTS AND CONCLUSION

For eight proteins, the antibody array signals were below detection range in all patient samples. None of the proteins showed levels at baseline or at start of maintenance with strong evidence for correlation to time to progression (lowest nominal p-value 0.03). The dynamic ranges of protein levels measured during the induction treatment period and during the maintenance period were analysed separately for time trends. Evidence for changing trends (up/down) in the levels of MMP-8, TIMP-4 and EGF was observed both during response to induction treatment and at progressive disease, respectively. For three of the proteins (IL-8, Activin A and IGFBP-2), weak evidence for correlation between increasing protein levels during induction with chemotherapy and bevacizumab and time to progression was observed. In conclusion, semi-quantitative profiling of angiogenesis related proteins in patient serum may be a versatile tool to screen for protein patterns aiming at identifying resistance mechanisms of anti-angiogenic treatment in patients with mCRC.

Genetic variants in CCL5 and CCR5 genes and serum VEGF-A levels predict efficacy of bevacizumab in metastatic colorectal cancer patients

Early VEGF-A reduction (EVR) by targeting abundant VEGF-A is a potential predictive marker of bevacizumab (BEV). The CCL5/CCR5 axis modulates VEGF-A production via endothelial progenitor cells migration. We tested whether genetic polymorphisms in the CCL5/CCR5 pathway could predict efficacy of BEV in patients with metastatic colorectal cancer (mCRC) in a first-line setting. Genomic DNA was extracted from 215 samples from three independent cohorts: 61 patients receiving FOLFOX+BEV (evaluation cohort); 83 patients receiving FOLFOX (control cohort); 71 patients receiving FOLFOX/XELOX+BEV (exploratory cohort) for validation and serum biochemistry assay (n = 48). Single nucleotide polymorphisms of genes in the CCL5/CCR5 pathway were analyzed by PCR-based direct sequencing. Considering the unbalanced distribution of patient baseline characteristics between the evaluation and control cohorts, propensity score matching analysis was performed. Serum VEGF-A levels during treatment were measured using ELISA. Among the evaluation and control cohorts, patients with any CCL5 rs2280789 G allele had longer progression-free survival (PFS) and overall survival (OS) when receiving FOLFOX+BEV than FOLFOX (PFS: 19.8 vs. 11.0 months, HR 0.44, 95%CI: 0.24-0.83, p = 0.004; OS: 41.8 vs. 24.5 months, HR: 0.50, 95%CI: 0.26-0.95, p = 0.024). No significant difference was shown in patients with the A/A variant. In the exploratory cohort, CCL5 rs2280789 G alleles were associated with higher VEGF-A levels at baseline and a greater decrease in VEGF-A levels at day 14 compared to the A/A variant. CCL5 and CCR5 impact the angiogenic environment, and the genotypes in CCL5/CCR5 genes may identify specific populations who will benefit from BEV in first-line treatment for mCRC.

IL-8 and thrombospondin-1 as prognostic markers in patients with metastatic colorectal cancer receiving bevacizumab

Purpose

Bevacizumab (B) plus chemotherapy (CT) is a common choice for first-line treatment of metastatic colorectal cancer. Molecular predictors of B efficacy have still not been identified. We analyzed the role of 22 angiogenesis-associated proteins in patient outcome.

Patients and methods

Serum samples collected at baseline and at the first clinical evaluation were available for 58 patients enrolled in the randomized multicenter ITACa trial and who received CT+ B. Serum protein levels were determined using multiplex ELISA.

Results

Patients with baseline ≥145 pg/mL IL-8 showed shorter median progression-free survival and overall survival (OS) than those with lower levels (6.5 vs 6. 12.6 months; HR 7.39, P<0.0001 and 8.7 vs 28.8 months, HR 7.68, P<0.001, respectively). Moreover, patients with baseline thrombospondin-1 levels ≥12,000 ng/mL had a better median OS than those with lower levels (34.5 vs 13.1 months, HR 0.43, P=0.007). Patients with a ≥20% reduction in IL-8 levels from baseline to first clinical evaluation showed a better progression-free survival and OS than the others (HR 0.41, P=0.005 and HR 0.43, P=0.007, respectively).

Conclusion

Baseline IL-8 and thrombospondin-1 levels and reduced IL-8 during B treatment could represent potential prognostic markers in metastatic colorectal cancer.

Prognostic and predictive factors for angiosarcoma patients receiving paclitaxel once weekly plus or minus bevacizumab: an ancillary study derived from a randomized clinical trial

BACKGROUND

We report here a correlation analysis conducted along with a phase II trial assessing bevacizumab in combination with weekly paclitaxel.

METHODS

Circulating pro/anti-angiogenic factors were assessed on day 1 (D1) and day 8 (D8). The prognostic value for progression-free survival (PFS) was evaluated using a Cox model with biomarkers as continuous variables.

RESULTS

Among the 51 patients enrolled and treated in this trial, biomarker analysis was performed for 42: 18 in Arm A (single-agent) and 24 in Arm B (combination). With a median follow-up of 46 months, PFS was 5.5 versus 5.7 months, respectively (p = 0.75). According to univariate analysis, factors associated with a poor PFS were as follows: visceral angiosarcoma, de novo angiosarcoma, and high PlGF and low VEGF-C baseline values. In multivariate analysis, de novo angiosarcoma (HR = 2.5; p = 0.024) and baseline VEGF-C value (HR = 0.7; p = 0.003) were significant prognostic factors. We observed a significant increase in circulating PlGF (< 0.001) and a decrease in VEGF (< 0.001) during bevacizumab treatment. An increase in FGF was associated with a poor outcome.

CONCLUSIONS

De novo angiosarcoma and a low baseline level of VEGF-C were found to be associated with a poor prognosis. Addition of bevacizumab induces major changes in circulating biomarkers (VEGF and PlGF) in a short timeframe without impacting PFS.

TRIAL REGISTRATION

Retrospectively registered on EudraCT N° 2009-017020-59 and NCT01303497 (February 24, 2011).

Copy number load predicts outcome of metastatic colorectal cancer patients receiving bevacizumab combination therapy

Increased copy number alterations (CNAs) indicative of chromosomal instability (CIN) have been associated with poor cancer outcome. Here, we study CNAs as potential biomarkers of bevacizumab (BVZ) response in metastatic colorectal cancer (mCRC). We cluster 409 mCRCs in three subclusters characterized by different degrees of CIN. Tumors belonging to intermediate-to-high instability clusters have improved outcome following chemotherapy plus BVZ versus chemotherapy alone. In contrast, low instability tumors, which amongst others consist of POLE-mutated and microsatellite-instable tumors, derive no further benefit from BVZ. This is confirmed in 81 mCRC tumors from the phase 2 MoMa study involving BVZ. CNA clusters overlap with CRC consensus molecular subtypes (CMS); CMS2/4 xenografts correspond to intermediate-to-high instability clusters and respond to FOLFOX chemotherapy plus mouse avastin (B20), while CMS1/3 xenografts match with low instability clusters and fail to respond. Overall, we identify copy number load as a novel potential predictive biomarker of BVZ combination therapy.

Increased copy number alterations, indicative of chromosomal instability, is associated with poor cancer outcome. Here, metastatic colorectal cancer patients displaying intermediate-high CIN associate with improved outcome following chemotherapy and bevacizumab treatment, suggesting CIN as a predictive biomarker.

Unexpected and durable response with regorafenib in a metastatic colorectal cancer patient without KDR mutation: A case report

RATIONALE

Regorafenib is an oral multikinase inhibitor and is approved as salvage therapy in the standard treatment of advanced colorectal cancer (CRC). Due to its limited efficacy, toxicity profile, and cost, it is necessary to identify those patients who may have the most benefit from regorafenib. In a previous case report, kinase insert domain receptor (KDR) mutation has been associated with exceptional clinical response (CR) in an elderly patient treated with a low dose of regorafenib; thus, it was hypothesized that it could represent a new predictive marker of drug response.

PATIENT CONCERNS

A heavily pretreated 67-year-old man with a wide peripancreatic recurrence of colon carcinoma and liver metastases was subjected to treatment with regorafenib.

DIAGNOSES

After 3 months of therapy, a computed tomography scan showed an impressive reduction of disease.

INTERVENTIONS

Regorafenib was given at full doses (160 mg/die for 21 days, every 4 weeks).

OUTCOMES

A lasting response without relevant toxicity. No KDR mutation relief was detected. After 13 months from the start of treatment, the patient died after the diagnosis of encephalic metastases.

LESSONS

Regorafenib can lead to an unexpected and durable CR with consistent progression-free survival and overall survival benefit even in patients affected by polychemotherapy refractory metastatic CRC. Further studies are needed to establish the benefit of KDR mutation as predictive marker for regorafenib sensitivity for patients with CRC. We include a detailed revision of prognostic and predictive factors of clinical outcome identified in literature to optimize the use of regorafenib in this setting.

Biomarkers of evasive resistance predict disease progression in cancer patients treated with antiangiogenic therapies

Numerous antiangiogenic agents are approved for the treatment of oncological diseases. However, almost all patients develop evasive resistance mechanisms against antiangiogenic therapies. Currently no predictive biomarker for therapy resistance or response has been established. Therefore, the aim of our study was to identify biomarkers predicting the development of therapy resistance in patients with hepatocellular cancer (n = 11), renal cell cancer (n = 7) and non-small cell lung cancer (n = 2). Thereby we measured levels of angiogenic growth factors, tumor perfusion, circulating endothelial cells (CEC), circulating endothelial progenitor cells (CEP) and tumor endothelial markers (TEM) in patients during the course of therapy with antiangiogenic agents, and correlated them with the time to antiangiogenic progression (aTTP). Importantly, at disease progression, we observed an increase of proangiogenic factors, upregulation of CEC/CEP levels and downregulation of TEMs, such as Robo4 and endothelial cell-specific chemotaxis regulator (ECSCR), reflecting the formation of torturous tumor vessels. Increased TEM expression levels tended to correlate with prolonged aTTP (ECSCR high = 275 days vs. ECSCR low = 92.5 days; p = 0.07 and for Robo4 high = 387 days vs. Robo4 low = 90.0 days; p = 0.08). This indicates that loss of vascular stabilization factors aggravates the development of antiangiogenic resistance. Thus, our observations confirm that CEP/CEC populations, proangiogenic cytokines and TEMs contribute to evasive resistance in antiangiogenic treated patients. Higher TEM expression during disease progression may have clinical and pathophysiological implications, however, validation of our results is warranted for further biomarker development.

Serum VEGF-A and CCL5 levels as candidate biomarkers for efficacy and toxicity of regorafenib in patients with metastatic colorectal cancer

Regorafenib is an oral multi-kinase inhibitor used as salvage therapy for metastatic colorectal cancer (mCRC). We tested whether serum cytokine levels are associated with clinical outcome in the mCRC patients receiving regorafenib. Serum samples were collected before treatment start, day 21, and progressive disease, and eleven angiogenic and inflammatory cytokine serum levels were examined. Fifty-four patients of a total of 62 enrolled patients were eligible for the analyses. The chemokine ligand 5 (CCL5) levels ≤ cut-off value (59959 pg/ml) at baseline was associated with relative tumor shrinkage (P = 0.021), better progression-free survival (PFS) (P = 0.036) and overall survival (OS) (P = 0.019). Vascular endothelial growth factor A (VEGF-A) levels showing a decrease on day 21 were significantly associated with a better PFS (P = 0.021). CCL5 levels ≤ cut-off was associated with any grade hand-foot skin reaction (HFSR) (P = 0.025) and thrombocytopenia (P = 0.013). Low chemokine ligand 2 levels at baseline were associated with grade 2 ≤ HFSR. High angiopoietin-2 and basic fibroblast growth factor (bFGF) levels at baseline were associated with grade 3 ≤ total bilirubin increase and transaminases increase, respectively. Low bFGF levels at baseline were associated with grade 3 ≤ hypertension. No correlation with severe events was observed. Baseline serum CCL5 levels and decrease of the serum VEGF-A levels may serve as potential predictive markers for survival or treatment-specific toxicities in mCRC patients receiving regorafenib.

Fibrocytes: A Novel Stromal Cells to Regulate Resistance to Anti-Angiogenic Therapy and Cancer Progression

An adequate blood supply is essential for cancer cells to survive and grow; thus, the concept of inhibiting tumor angiogenesis has been applied to cancer therapy, and several drugs are already in clinical use. It has been shown that treatment with those anti-angiogenic drugs improved the response rate and prolonged the survival of patients with various types of cancer; however, it is also true that the effect was mostly limited. Currently, the disappointing clinical results are explained by the existence of intrinsic or acquired resistance to the therapy mediated by both tumor cells and stromal cells. This article reviews the mechanisms of resistance mediated by stromal cells such as endothelial cells, pericytes, fibroblasts and myeloid cells, with an emphasis on fibrocytes, which were recently identified as the cell type responsible for regulating acquired resistance to anti-angiogenic therapy. In addition, the other emerging role of fibrocytes as mediator-producing cells in tumor progression is discussed.

Predictive biomarkers candidates for patients with metastatic colorectal cancer treated with bevacizumab-containing regimen

Bevacizumab was the first molecular-targeted antiangiogenic therapy approved for the treatment of metastatic colorectal cancer. Until now, there are no predictive biomarkers available to decide the prescription of bevacizumab in patients with colorectal cancer. The purposes of this review were to provide a critical appraisal of the evidence and to identify possible predictive genetic biomarkers. A literature search was performed to identify studies that determine different levels of treatment response between patients stratified according to defined biomarkers. Interesting findings were reported between patients stratified according to rs3025039 and rs833061 polymorphisms of the gene VEGFA, with statistically and clinically significant differences for progression-free survival and overall survival. However, another study conducted in a larger sample does not confirm these previous findings, suggesting that well-designed prospective studies are still needed to achieve conclusive results. FLT1 (or VEGFR1) rs9513070 seems to be an interesting candidate as a predictive biomarker, with differences of more than 10 months in OS between different patients groups. In our opinion, possible interesting biomarker candidates for future research could be the polymorphisms rs833061 and rs3025039 of VEGF-A, rs9513070 or haplotype analysis of FLT1, rs2661280 of RGS5, rs444903 and rs6220 of EGF and Ang-2 or LDH plasma levels.

Characteristics of the specific humoral response in patients with advanced solid tumors after active immunotherapy with a VEGF vaccine, at different antigen doses and using two distinct adjuvants

Background

CIGB-247, a VSSP-adjuvanted VEGF-based vaccine, was evaluated in a phase I clinical trial in patients with advanced solid tumors (CENTAURO). Vaccination with the maximum dose of antigen showed an excellent safety profile, exhibited the highest immunogenicity and was the only one showing a reduction on platelet VEGF bioavailability. However, this antigen dose level did not achieve a complete seroconversion rate in vaccinated patients. These clinical results led us to the question whether a “reserve” of untapped immune response potential against VEGF could exist in cancer patients. To address this matter, CENTAURO-2 clinical trial was conducted where antigen and VSSP dose scale up were studied, and also incorporated the exploration of aluminum phosphate as adjuvant. These changes were made with the aim to increase immune response against VEGF.

Results

The present study reports the characterization of the humoral response elicited by CIGB-247 from the combining of different antigen doses and adjuvants. Cancer patients were immunologically monitored for approximately 1 year. Vaccination with different CIGB-247 formulations exhibited a very positive safety profile. Cancer patients developed IgM, IgG or IgA antibodies specific to VEGF. Elicited polyclonal antibodies had the ability to block the interaction between VEGF and its receptors, VEGFR1 and VEGFR2. The highest humoral response was detected in patients immunized with 800 μg of antigen + 200 μg of VSSP. Off-protocol long-term vaccination did not produce negative changes in humoral response.

Conclusions

Vaccination with a human VEGF variant molecule as antigen in combination with VSSP or aluminum phosphate is immunogenic. The results of this study could contribute to the investigation of this vaccine therapy in an adequately powered efficacy trial.

Trial registration

Trial registration number: RPCEC00000155. Cuban Public Clinical Trial Registry. Date of registration: June 06, 2013. Available from: http://registroclinico.sld.cu/.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-017-0222-z) contains supplementary material, which is available to authorized users.

Prognostic importance of circulating epidermal growth factor-like domain 7 in patients with metastatic colorectal cancer treated with chemotherapy and bevacizumab

High tumor expression of epidermal growth factor-like domain 7 (EGFL7) has been associated with a poor prognosis in colorectal cancer. The aim of the current study was to investigate the possible prognostic impact of circulating EGFL7 (cir-EGFL7), combined with single nucleotide polymorphism (SNP) analyses, in patients with metastatic colorectal cancer (mCRC) treated with first line chemotherapy and bevacizumab. A total of 88 patients were included. Serum was collected prior to treatment initiation, at first evaluation after 3 weeks, and at progression. Cir-EGFL7 was analysed by the enzyme-linked immunosorbent assay (ELISA) technique. The SNPs were analysed by real-time qPCR based on DNA from whole blood. Endpoints were response rate (RR), progression free survival (PFS), and overall survival (OS). Cir-EGFL7 decreases after administration of chemotherapy plus bevacizumab. Baseline levels of cir-EGFL7 were significantly related to PFS and OS, p = 0.0431 and p = 0.0017, respectively, with increasing cir-EGFL7 levels associated with a worse prognosis. Circulating EGFL7 was not associated with RR. The SNP analyses revealed a significant relationship between rs1051851 and OS, p = 0.030. This study demonstrates that cir-EGFL7 changes during treatment with chemotherapy plus bevacizumab and that baseline levels and genetic variations may influence the overall prognosis of patients with mCRC. The findings call for further validation.

Colorectal Cancer: From the Genetic Model to Posttranscriptional Regulation by Noncoding RNAs

Colorectal cancer is the third most common form of cancer in developed countries and, despite the improvements achieved in its treatment options, remains as one of the main causes of cancer-related death. In this review, we first focus on colorectal carcinogenesis and on the genetic and epigenetic alterations involved. In addition, noncoding RNAs have been shown to be important regulators of gene expression. We present a general overview of what is known about these molecules and their role and dysregulation in cancer, with a special focus on the biogenesis, characteristics, and function of microRNAs. These molecules are important regulators of carcinogenesis, progression, invasion, angiogenesis, and metastases in cancer, including colorectal cancer. For this reason, miRNAs can be used as potential biomarkers for diagnosis, prognosis, and efficacy of chemotherapeutic treatments, or even as therapeutic agents, or as targets by themselves. Thus, this review highlights the importance of miRNAs in the development, progression, diagnosis, and therapy of colorectal cancer and summarizes current therapeutic approaches for the treatment of colorectal cancer.

Circulating VEGF and eNOS variations as predictors of outcome in metastatic colorectal cancer patients receiving bevacizumab. Sci Rep. 2017;7:1293. [PMID: 28465540 PMCID: PMC5431064 DOI: 10.1038/s41598-017-01420-0]

Novel predictive biomarkers are needed to improve patient selection and optimize the use of bevacizumab (B) in metastatic colorectal cancer. We analyzed the potential of five circulating biomarkers to predict B efficacy and monitor response. Peripheral blood samples collected at baseline, at the first clinical evaluation and at progression were available for 129 patients enrolled in the prospective multicentric ITACa trial and randomized to receive FOLFOX4/FOLFIRI (CT) with (64 patients) or without B (65 patients). VEGF-A, eNOS, EPHB4, COX2 and HIF-1α mRNA levels were measured by qRT-PCR. Baseline marker expression levels and their modulation during therapy were analyzed in relation to objective response, progression-free survival and overall survival (OS). VEGF and eNOS expression was significantly correlated in both groups (Spearman’s correlation coefficient = 0.80; P < 0.0001 and 0.75; P < 0.0001, respectively). B-treated patients with >30% reduction in eNOS and VEGF levels from baseline to the first clinical evaluation showed better OS than the others (median OS 31.6 months, 95% CI 21.3–49.5 months and median OS 14.4 months, 95% CI 9.0–22.7 months, respectively, HR 0.38, 95% CI 0.19–0.78, P = 0.008). A reduction in eNOS and VEGF expression from baseline to the first clinical evaluation may indicate a response to B.

A functional bioassay to determine the activity of anti-VEGF antibody therapy in blood of patients with cancer

Background:

Only a small proportion of patients respond to anti-VEGF therapy, pressing the need for a reliable biomarker that can identify patients who will benefit. We studied the biological activity of anti-VEGF antibodies in patients' blood during anti-VEGF therapy by using the Ba/F3-VEGFR2 cell line, which is dependent on VEGF for its growth.

Methods:

Serum samples from 22 patients with cancer before and during treatment with bevacizumab were tested for their effect on proliferation of Ba/F3-VEGFR2 cells. Vascular endothelial growth factor as well as bevacizumab concentrations in serum samples from these patients were determined by enzyme linked immunosorbent assay (ELISA).

Results:

The hVEGF-driven cell proliferation was effectively blocked by bevacizumab (IC₅₀ 3.7 μg ml⁻¹; 95% CI 1.7–8.3 μg ml⁻¹). Cell proliferation was significantly reduced when patients' serum during treatment with bevacizumab was added (22–103% inhibition compared with pre-treatment). Although bevacizumab levels were not related, on-treatment serum VEGF levels were correlated with Ba/F3-VEGFR2 cell proliferation.

Conclusions:

We found that the neutralising effect of anti-VEGF antibody therapy on the biological activity of circulating VEGF can be accurately determined with a Ba/F3-VEGFR2 bioassay. The value of this bioassay to predict clinical benefit of anti-VEGF antibody therapy needs further clinical evaluation in a larger randomised cohort.

Predictive Biomarkers in Colorectal Cancer: From the Single Therapeutic Target to a Plethora of Options

Colorectal cancer (CRC) is one of the most frequent cancers and is a leading cause of cancer death worldwide. Treatments used for CRC may include some combination of surgery, radiation therapy, chemotherapy, and targeted therapy. The current standard drugs used in chemotherapy are 5-fluorouracil and leucovorin in combination with irinotecan and/or oxaliplatin. Most recently, biologic agents have been proven to have therapeutic benefits in metastatic CRC alone or in association with standard chemotherapy. However, patients present different treatment responses, in terms of efficacy and toxicity; therefore, it is important to identify biological markers that can predict the response to therapy and help select patients that would benefit from specific regimens. In this paper, authors review CRC genetic markers that could be useful in predicting the sensitivity/resistance to chemotherapy.

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

INTRODUCTION

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

AREAS COVERED

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

Novel anti-angiogenic therapeutic strategies in colorectal cancer

INTRODUCTION

Anti-angiogenetic agents are currently the standard of care in metastatic CRC patients. Bevacizumab, aflibercept, regorafenib and recently ramucirumab have significantly improved both progression-free and overall survival in different lines of treatment. Since bevacizumab's approval, a number of novel anti-VEGF agents have been tested in preclinical and clinical models.

AREAS COVERED

This review is focused on the most recent clinical results of novel agents targeting VEGF and its receptors with a major focus on those investigated recently in clinical trials.

EXPERT OPINION

In the last 15 years, a number of new anti-angiogenetic agents have been tested. Unfortunately, most of them have demonstrated unacceptable toxicities or failed to show activity. When tested as single agents, encouraging preliminary results were reported with fruquintinib, famitinib, and nintedanib. Interesting novel mechanisms of action are also being explored: VGX-100 is a monoclonal antibody (mAb) which binds to VEGF-C, inhibiting activation of VEGFR-2 and VEGFR-3 when combined with bevacizumab; tanibirumab is a mAb which binds to VEGFR-2 and vanucizumab is a bispecific mAb binding both to VEGF-A and Angiopoietin-2. Data about the combination of these agents with chemotherapy are very encouraging, even though preliminary. However, the definition of specific predictive biomarkers remains a priority.

Dynamic Contrast-Enhanced Magnetic Resonance Imaging as a Surrogate Biomarker for Bevacizumab in Colorectal Cancer Liver Metastasis: A Single-Arm, Exploratory Trial

Purpose

The purpose of this study is to investigate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and plasma cytokines and angiogenic factors (CAFs) as pharmacodynamic and prognostic biomarkers of bevacizumab monotherapy in colorectal cancer with liver metastasis (CRCLM).

Materials and Methods

From July 2011 to March 2012, 28 patients with histologically confirmed CRCLM received bevacizumab monotherapy followed by combined FOLFOX therapy. The mean age of the patients was 57 years (range, 30 to 77 years). DCE-MRI (K^transand IAUC₆₀) was performed at baseline, first follow-up (3 days after bevacizumab monotherapy), and second follow-up (3 days after combined therapy). CAF levels (vascular endothelial growth factor [VEGF], placental growth factor [PlGF], and interleukin-8) were assessed on the same days. Progression-free survival (PFS) time distributions were summarized using the Kaplan-Meier method and compared using log-rank tests.

Results

The median PFS period was 11.2 months. K^trans, IAUC₆₀, VEGF, and PlGF values on the first follow-up day were significantly different compared with baseline values. No differences were observed on the second follow-up day. A > 40% decrease in K^trans from baseline to first follow-up was associated with a longer PFS (hazard ratio, 0.349; 95% confidence interval, 0.133 to 0.912; p=0.032). Changes in CAFs did not show correlation with PFS time.

Conclusion

DCE-MRI parameters and CAFs are pharmacodynamic biomarkers of bevacizumab for CRCLM. In our study, change in K^trans at 3 days after bevacizumab monotherapy was a favorable prognostic factor; however, the value of CAFs as a prognostic biomarker was not found.

A randomized phase 3 study on the optimization of the combination of bevacizumab with FOLFOX/OXXEL in the treatment of patients with metastatic colorectal cancer-OBELICS (Optimization of BEvacizumab scheduLIng within Chemotherapy Scheme)

BACKGROUND

Despite the improvements in diagnosis and treatment, colorectal cancer (CRC) is the second cause of cancer deaths in both sexes. Therefore, research in this field remains of great interest. The approval of bevacizumab, a humanized anti-vascular endothelial growth factor (VEGF) monoclonal antibody, in combination with a fluoropyrimidine-based chemotherapy in the treatment of metastatic CRC has changed the oncology practice in this disease. However, the efficacy of bevacizumab-based treatment, has thus far been rather modest. Efforts are ongoing to understand the better way to combine bevacizumab and chemotherapy, and to identify valid predictive biomarkers of benefit to avoid unnecessary and costly therapy to nonresponder patients. The BRANCH study in high-risk locally advanced rectal cancer patients showed that varying bevacizumab schedule may impact on the feasibility and efficacy of chemo-radiotherapy.

METHODS/DESIGN

OBELICS is a multicentre, open-label, randomised phase 3 trial comparing in mCRC patients two treatment arms (1:1): standard concomitant administration of bevacizumab with chemotherapy (mFOLFOX/OXXEL regimen) vs experimental sequential bevacizumab given 4 days before chemotherapy, as first or second treatment line. Primary end point is the objective response rate (ORR) measured according to RECIST criteria. A sample size of 230 patients was calculated allowing reliable assessment in all plausible first-second line case-mix conditions, with a 80% statistical power and 2-sided alpha error of 0.05. Secondary endpoints are progression free-survival (PFS), overall survival (OS), toxicity and quality of life. The evaluation of the potential predictive role of several circulating biomarkers (circulating endothelial cells and progenitors, VEGF and VEGF-R SNPs, cytokines, microRNAs, free circulating DNA) as well as the value of the early [(18)F]-Fluorodeoxyglucose positron emission tomography (FDG-PET) response, are the objectives of the traslational project.

DISCUSSION

Overall this study could optimize bevacizumab scheduling in combination with chemotherapy in mCRC patients. Moreover, correlative studies could improve the knowledge of the mechanisms by which bevacizumab enhance chemotherapy effect and could identify early predictors of response. EudraCT Number: 2011-004997-27 TRIAL REGISTRATION: ClinicalTrials.gove number, NCT01718873.

Understanding the FOLFOXIRI-regimen to optimize treatment for metastatic colorectal cancer

The management of metastatic colorectal cancer substantially improved over the last 10 years and median overall survival of patients might exceed 30 months. The selection of an effective first-line treatment represents a crucial point in order to achieve good outcome results. In the last years, the intensive FOLFOXIRI regimen in combination with bevacizumab became a new standard option in this setting. In the present review we summarized the main steps of FOLFOXIRI regimen development from the first pilot study to the recent findings with biological agents, with a specific focus on practical aspects, such as patient's selection, adverse event management, treatment schedules and post-progression strategies. Possible predictive markers, open issues and ongoing clinical trials have been also deeply described.

Fibrocyte-like cells mediate acquired resistance to anti-angiogenic therapy with bevacizumab

Bevacizumab exerts anti-angiogenic effects in cancer patients by inhibiting vascular endothelial growth factor (VEGF). However, its use is still limited due to the development of resistance to the treatment. Such resistance can be regulated by various factors, although the underlying mechanisms remain incompletely understood. Here we show that bone marrow-derived fibrocyte-like cells, defined as alpha-1 type I collagen-positive and CXCR4-positive cells, contribute to the acquired resistance to bevacizumab. In mouse models of malignant pleural mesothelioma and lung cancer, fibrocyte-like cells mediate the resistance to bevacizumab as the main producer of fibroblast growth factor 2. In clinical specimens of lung cancer, the number of fibrocyte-like cells is significantly increased in bevacizumab-treated tumours, and correlates with the number of treatment cycles, as well as CD31-positive vessels. Our results identify fibrocyte-like cells as a promising cell biomarker and a potential therapeutic target to overcome resistance to anti-VEGF therapy.

Identification of a Novel Pathogenic Germline KDR Variant in Melanoma

PURPOSE

The application of pan-cancer next-generation sequencing panels in the clinical setting has facilitated the identification of low frequency somatic mutations and the testing of new therapies in solid tumors using the "basket trial" scheme. However, little consideration has been given to the relevance of nonsynonymous germline variants, which are likely to be uncovered in tumors and germline and which may be relevant to prognostication and prediction of treatment response.

EXPERIMENTAL DESIGN

We analyzed matched tumor and normal DNA from 34 melanoma patients using an Ion Torrent cancer-associated gene panel. We elected to study the germline variant Q472H in the kinase insert domain receptor (KDR), which was identified in 35% of melanoma patients in both a pilot and an independent 1,223 patient cohort. Using patient-derived melanoma cell lines and human samples, we assessed proliferation, invasion, VEGF levels, and angiogenesis by analyzing tumor microvessel density (MVD) using anti-CD34 antibody.

RESULTS

Serum VEGF levels and tumor MVD were significantly higher in Q472H versus KDR wild-type (WD) patients. Primary cultures derived from melanomas harboring the KDR variant were more proliferative and invasive than KDR wild type. Finally, using a VEGFR2 antibody, we showed that KDR Q472H cells were sensitive to targeted inhibition of VEGFR2, an effect that was not observed in KDR WT cells.

CONCLUSIONS

Our data support the integration of germline analysis into personalized treatment decision-making and suggest that patients with germline KDR variant might benefit from antiangiogenesis treatment. Clin Cancer Res; 22(10); 2377-85. ©2015 AACR.

Rationale and Design for the LUME-Colon 1 Study: A Randomized, Double-Blind, Placebo-Controlled Phase III Trial of Nintedanib Plus Best Supportive Care Versus Placebo Plus Best Supportive Care in Patients With Advanced Colorectal Cancer Refractory to Standard Treatment

BACKGROUND

Clinical studies of antivascular endothelial growth factor (anti-VEGF) agents have demonstrated that angiogenesis is critical to colorectal cancer (CRC) tumor growth and metastasis. Nintedanib is a triple angiokinase inhibitor of VEGF, platelet-derived growth factor, and fibroblast growth factor signaling. Nintedanib, combined with docetaxel, has been approved in the European Union for the treatment of patients with non-small-cell lung cancer with adenocarcinoma tumor histologic type after first-line chemotherapy. The objective of the present study (1199.52; clinicaltrials.gov identifier NCT02149108; LUME-Colon 1) is to evaluate the efficacy and safety of nintedanib plus best supportive care (BSC) in patients with advanced colorectal cancer refractory to standard chemotherapy regimens and biologic agents.

PATIENTS AND METHODS

A total of 764 patients worldwide will be randomized 1:1 to receive either nintedanib 200 mg twice daily plus BSC or placebo plus BSC in 21-day courses until disease progression, undue toxicity, or withdrawal of informed consent. The primary endpoints are progression-free survival (PFS) and overall survival (OS). The secondary endpoints are the objective tumor response and disease control. PFS and OS will be evaluated using a log-rank test to determine the effect of nintedanib independently at the 2-sided α-level of 0.05. Other assessments will include the frequency and severity of adverse events and changes in laboratory parameters to measure the safety, health-related quality of life, and pharmacogenomic analyses, focusing on exploring the predictive biomarkers and drug-resistance mechanisms. The results are expected in 2016.

Genetic variants in VEGF pathway genes in neoadjuvant breast cancer patients receiving bevacizumab: Results from the randomized phase III GeparQuinto study

Studies assessing the effect of bevacizumab (BEV) on breast cancer (BC) outcome have shown different effects on progression-free and overall survival, suggesting that a subgroup of patients may benefit from this treatment. Unfortunately, no biomarkers exist to identify these patients. Here, we investigate whether single nucleotide polymorphisms (SNPs) in VEGF pathway genes correlate with pathological complete response (pCR) in the neoadjuvant GeparQuinto trial. HER2-negative patients were randomized into treatment arms receiving either BEV combined with standard chemotherapy or chemotherapy alone. In a pre-planned biomarker study, DNA was collected from 729 and 724 patients, respectively from both treatment arms, and genotyped for 125 SNPs. Logistic regression assessed interaction between individual SNPs and both treatment arms to predict pCR. Five SNPs may be associated with a better response to BEV, but none of them remained significant after correction for multiple testing. The two SNPs most strongly associated, rs833058 and rs699947, were located upstream of the VEGF-A promoter. Odds ratios for the homozygous common, heterozygous and homozygous rare rs833058 genotypes were 2.36 (95% CI, 1.49-3.75), 1.20 (95% CI, 0.88-1.64) and 0.61 (95% CI, 0.34-1.12). Notably, some SNPs in VEGF-A exhibited a more pronounced effect in the triple-negative subgroup. Several SNPs in VEGF-A may be associated with improved pCR when receiving BEV in the neoadjuvant setting. Although none of the observed effects survived correction for multiple testing, our observations are consistent with previous studies on BEV efficacy in BC. Further research is warranted to clarify the predictive value of these markers.

Targeting Angiogenesis in Cancer Therapy: Moving Beyond Vascular Endothelial Growth Factor

Angiogenesis, or the formation of new capillary blood vessels, occurs primarily during human development and reproduction; however, aberrant regulation of angiogenesis is also a fundamental process found in several pathologic conditions, including cancer. As a process required for invasion and metastasis, tumor angiogenesis constitutes an important point of control of cancer progression. Although not yet completely understood, the complex process of tumor angiogenesis involves highly regulated orchestration of multiple signaling pathways. The proangiogenic signaling molecule vascular endothelial growth factor (VEGF) and its cognate receptor (VEGF receptor 2 [VEGFR-2]) play a central role in angiogenesis and often are highly expressed in human cancers, and initial clinical efforts to develop antiangiogenic treatments focused largely on inhibiting VEGF/VEGFR signaling. Such approaches, however, often lead to transient responses and further disease progression because angiogenesis is regulated by multiple pathways that are able to compensate for each other when single pathways are inhibited. The platelet-derived growth factor (PDGF) and PDGF receptor (PDGFR) and fibroblast growth factor (FGF) and FGF receptor (FGFR) pathways, for example, provide potential escape mechanisms from anti-VEGF/VEGFR therapy that could facilitate resumption of tumor growth. Accordingly, more recent treatments have focused on inhibiting multiple signaling pathways simultaneously. This comprehensive review discusses the limitations of inhibiting VEGF signaling alone as an antiangiogenic strategy, the importance of other angiogenic pathways including PDGF/PDGFR and FGF/FGFR, and the novel current and emerging agents that target multiple angiogenic pathways for the treatment of advanced solid tumors.

IMPLICATIONS FOR PRACTICE

Significant advances in cancer treatment have been achieved with the development of antiangiogenic agents, the majority of which have focused on inhibition of the vascular endothelial growth factor (VEGF) pathway. VEGF targeting alone, however, has not proven to be as efficacious as originally hoped, and it is increasingly clear that there are many interconnected and compensatory pathways that can overcome VEGF-targeted inhibition of angiogenesis. Maximizing the potential of antiangiogenic therapy is likely to require a broader therapeutic approach using a new generation of multitargeted antiangiogenic agents.

Vascular Endothelial Growth Factor A c.*237C>T polymorphism is associated with bevacizumab efficacy and related hypertension in metastatic colorectal cancer

BACKGROUND

No predictive marker has been yet identified for bevacizumab which is widely used in metastatic colorectal cancer.

AIMS

Evaluate impact of single nucleotide polymorphisms involved in Vascular Endothelial Growth Factor pathway on efficacy and tolerance of bevacizumab.

METHODS

We retrospectively included patients who were treated with bevacizumab-based chemotherapy for metastatic colorectal cancer, and for whom a deoxyribonucleic acid sample was available. Ten polymorphisms in Vascular Endothelial Growth Factor-A, his receptors and hypoxia inducible factor-1α were genotyped on germ line DNA using real-time polymerase chain reaction TaqMan(®).

RESULTS

89 patients were included. The CC genotype for rs3025039 (Vascular Endothelial Growth Factor-A c.*237C>T) was associated with a significantly better time to treatment failure (14.2 months) as compared to the CT and TT genotypes (6.0 months) in univariate (p = 0.004) and multivariate (p = 0.022; HR = 0.57; 95% CI [0.35-0.92]) analysis. Patients with at least one T allele showed worse overall survival and progression-free survival as compared to homozygous CC patients in univariate analysis (respectively p = 0.016 and p = 0.044). There was significantly more severe hypertension for the CC genotype (29.5%) compared to CT and TT genotypes (7.1%) (p = 0.022) in multivariate analysis.

CONCLUSIONS

In this retrospective study, the rs3025039 polymorphism was significantly associated with time to treatment failure and hypertension in patients treated with bevacizumab-based chemotherapy.

A pharmacokinetic binding model for bevacizumab and VEGF165 in colorectal cancer patients

PURPOSE

To characterize the population pharmacokinetics of bevacizumab, its binding properties to VEGF165 and the effect of demographic data and VEGF-A polymorphisms on the interplay between bevacizumab serum pharmacokinetics and VEGF165 serum concentrations in patients with colorectal cancer stage IV.

METHODS

Bevacizumab and VEGF165 data were collected from 19 adult patients with metastatic colorectal cancer enrolled in an observational clinical study. Bevacizumab was administered with one of the following combinations: 5-FU/Leucovorin/Irinotecan, 5-FU/Leucovorin/Oxaliplatin, Capecitabine/Irinotecan at doses ranging from 5 to 10 mg/kg every 2 or 3 weeks. Data analysis was performed using nonlinear mixed-effects modeling implemented in NONMEM 7.3.

RESULTS

A target-mediated drug disposition model adequately described bevacizumab concentration changes over time and its binding characteristics to VEGF165. The estimated clearance of bevacizumab was 0.18 L/day, the free VEGF165 levels at baseline were 212 ng/L, and the elimination rate constant of free VEGF165 was 0.401 day(-1). Body weight was allometrically included in all PK parameters.

CONCLUSION

The final model adequately described the pre- and post-dose concentrations of total bevacizumab and free VEGF165 in patients with colorectal cancer. Model parameters were consistent with those previously reported for patients with solid tumors. Correlations between the binding affinity of bevacizumab and the VEGF-2578C/A and VEGF-634G/C polymorphisms were noticed.

Combining bevacizumab and chemoradiation in rectal cancer. Translational results of the AXEBeam trial

Background:

This study characterises molecular effect of bevacizumab, and explores the relation of molecular and genetic markers with response to bevacizumab combined with chemoradiotherapy (CRT).

Methods:

From a subset of 59 patients of 84 rectal cancer patients included in a phase II study combining bevacizumab with CRT, tumour and blood samples were collected before and during treatment, offering the possibility to evaluate changes induced by one dose of bevacizumab. We performed cDNA microarrays, stains for CD31/CD34 combined with α-SMA and CA-IX, as well as enzyme-linked immunosorbent assay (ELISA) for circulating angiogenic proteins. Markers were related with the pathological response of patients.

Results:

One dose of bevacizumab changed the expression of 14 genes and led to a significant decrease in microvessel density and in the proportion of pericyte-covered blood vessels, and a small but nonsignificant increase in hypoxia. Alterations in angiogenic processes after bevacizumab delivery were only detected in responding tumours. Lower PDGFA expression and PDGF-BB levels, less pericyte-covered blood vessels and higher CA-IX expression were found after bevacizumab treatment only in patients with pathological complete response.

Conclusions:

We could not support the ‘normalization hypothesis' and suggest a role for PDGFA, PDGF-BB, CA-IX and α-SMA. Validation in larger patient groups is needed.

Biomarkers of reactive resistance and early disease progression during chemotherapy plus bevacizumab treatment for colorectal carcinoma

Molecular markers for predicting or monitoring the efficacy of bevacizumab in patients with metastatic colorectal cancer (mCRC) remain to be identified. We have now measured the serum concentrations of 25 angiogenesis-related molecules with antibody suspension bead array systems for 25 mCRC patients both before and during treatment in a previously reported phase II trial of FOLFIRI chemotherapy plus bevacizumab. The serum concentration of vascular endothelial growth factor-A (VEGF-A) decreased after the onset of treatment (P < 0.0001), whereas that of placental growth factor increased (P < 0.0001). Significant differences in the levels of several factors (such as VEGF-A, soluble VEGF receptor-2, and interleukin-8) were apparent between responders and nonresponders during treatment. The rapid and pronounced decrease in serum VEGF-A level after treatment onset was apparent in all subjects and was independent of the baseline concentration. However, four of nine nonresponders showed a subsequent early increase in the serum VEGF-A level. Our results thus suggest that an early increase in the serum VEGF-A concentration after the initial decrease is a potential predictive marker of a poor response and reactive resistance to bevacizumab plus chemotherapy.

Pharmacogenetics and breast cancer management: current status and perspectives

INTRODUCTION

Breast cancer has benefited from a number of innovative therapeutics over the last decade. Cytotoxics, hormone therapy, targeted therapies and biologics can now be given to ensure optimal management of patients. As life expectancy of breast cancer patients has been significantly stretched and that several lines of treatment are now made available, determining the best drug or drug combinations to be primarily given and the best dosing and scheduling for each patient is critical for ensuring an optimal toxicity/efficacy balance.

AREAS COVERED

Defining patient's characteristics at the tumor level (pharmacogenomics) and the constitutional level (pharmacogenetics) is a rising trend in oncology. This review covers the latest strategies based upon the search of relevant biomarkers for efficacy, resistance and toxicity to be undertaken at the bedside to shift towards precision medicine in breast cancer patients.

EXPERT OPINION

In the expanding era of bioguided medicine, identifying relevant and clinically validated biomarkers from the plethora of published material remains an uneasy task. Sorting the variety of genetic and molecular markers that have been investigated over the last decade on their level of evidence and addressing the issue of drug exposure should help to improve the management of breast cancer therapy.

Computational systems biology approaches to anti-angiogenic cancer therapeutics

Angiogenesis is an exquisitely regulated process that is required for physiological processes and is also important in numerous diseases. Tumors utilize angiogenesis to generate the vascular network needed to supply the cancer cells with nutrients and oxygen, and many cancer drugs aim to inhibit tumor angiogenesis. Anti-angiogenic therapy involves inhibiting multiple cell types, molecular targets, and intracellular signaling pathways. Computational tools are useful in guiding treatment strategies, predicting the response to treatment, and identifying new targets of interest. Here, we describe progress that has been made in applying mathematical modeling and bioinformatics approaches to study anti-angiogenic therapeutics in cancer.

Circulating biomarkers in advanced colorectal cancer patients randomly assigned to three bevacizumab-based regimens

The need to identify biomarkers for bevacizumab-based treatment in advanced colorectal cancer is imperative. The aim of this study was to investigate the prognostic role of circulating VEGF, PDGF, SDF-1, osteopontin and CEA in patients randomly assigned to three bevacizumab-based regimens. Plasma samples from 50 patients treated at a single Institution were analysed using the multiplex assay BioPlex™ 2200 (Bio-Rad Laboratories, Inc, Berkeley, CA, USA) at baseline, before first three cycles and subsequently every three cycles until disease progression. Prognostic analyses of baseline values were performed using multivariable Cox models, including disease extension >10 cm or ≤10 cm (measured as the sum of the diameters for all target lesions) as adjustment factor. The association between progression-free and overall survival and biomarkers modulation during treatment was studied using multivariable Cox models, which included summary statistics synthesizing during-treatment modulation together with disease extension. The biomarkers significantly associated with disease extension were baseline CEA (p = 0.012) and SDF-1 (p = 0.030). High values of VEGF and SDF-1 tended to be associated with worse prognosis, especially in terms of overall survival. The negative prognostic trend was more marked for baseline CEA as compared to other biomarkers; increasing values during treatment was significantly related to worse prognosis independently of disease extension (p = 0.007 and 0.016 for progression-free and overall survival, respectively). VEGF is related to bevacizumab pharmacodynamics and is associated to other angiogenic cytokines; some of the proposed biomarkers such as SDF-1 and CEA should be further validated for prognosis assessment and monitoring of bevacizumab-based treatment of advanced colorectal cancer.

Genetic variability of VEGF pathway genes in six randomized phase III trials assessing the addition of bevacizumab to standard therapy

BACKGROUND

Despite extensive translational research, no validated biomarkers predictive of bevacizumab treatment outcome have been identified.

METHODS

We performed a meta-analysis of individual patient data from six randomized phase III trials in colorectal, pancreatic, lung, renal, breast, and gastric cancer to explore the potential relationships between 195 common genetic variants in the vascular endothelial growth factor (VEGF) pathway and bevacizumab treatment outcome.

RESULTS

The analysis included 1,402 patients (716 bevacizumab-treated and 686 placebo-treated). Twenty variants were associated (P < 0.05) with progression-free survival (PFS) in bevacizumab-treated patients. Of these, 4 variants in EPAS1 survived correction for multiple testing (q < 0.05). Genotype-by-treatment interaction tests revealed that, across these 20 variants, 3 variants in VEGF-C (rs12510099), EPAS1 (rs4953344), and IL8RA (rs2234671) were potentially predictive (P < 0.05), but not resistant to multiple testing (q > 0.05). A weak genotype-by-treatment interaction effect was also observed for rs699946 in VEGF-A, whereas Bayesian genewise analysis revealed that genetic variability in VHL was associated with PFS in the bevacizumab arm (q < 0.05). Variants in VEGF-A, EPAS1, and VHL were located in expression quantitative loci derived from lymphoblastoid cell lines, indicating that they affect the expression levels of their respective gene.

CONCLUSIONS

This large genetic analysis suggests that variants in VEGF-A, EPAS1, IL8RA, VHL, and VEGF-C have potential value in predicting bevacizumab treatment outcome across tumor types. Although these associations did not survive correction for multiple testing in a genotype-by-interaction analysis, they are among the strongest predictive effects reported to date for genetic variants and bevacizumab efficacy.