Prognostic and predictive value of VEGF,sVEGFR-2 and CEA in mCRC studies comparing cediranib,bevacizumab and chemotherapy

Background:

The prognostic/predictive value of potential vascular endothelial growth factor (VEGF) signalling biomarkers was evaluated retrospectively using samples from two randomized Phase III studies (HORIZON II and III) investigating cediranib in metastatic colorectal cancer (mCRC).

Methods:

Baseline levels of VEGF, soluble VEGF receptor-2 (sVEGFR-2) and carcinoembryonic antigen (CEA) were measured in plasma/serum samples collected from patients participating in HORIZON II (n=860; FOLFOX/XELOX plus cediranib 20 mg (n=502) or placebo (n=358)) and HORIZON III (n=1422; mFOLFOX6 plus cediranib 20 mg (n=709) or bevacizumab (n=713)). Median biomarker baseline levels determined cutoff values for the patient subgroups.

Results:

Baseline data were available for 88–97% of patients/study (>2000 patients). In both the studies, high baseline VEGF and CEA were associated with worse outcomes for progression-free survival (PFS) and overall survival (OS) independent of treatment (HORIZON II OS: VEGF, hazard ratio (HR)=1.35 (95% confidence interval (CI): 1.12–1.63); CEA, HR=1.63 (1.36–1.96); HORIZON III OS: VEGF, HR=1.32 (1.12–1.54); CEA, HR=1.50 (1.29–1.76)). sVEGFR-2 was not prognostic for PFS/OS. Baseline VEGF and CEA were not predictive for PFS/OS outcome to cediranib treatment; low sVEGFR-2 was associated with a trend towards improved cediranib effect in HORIZON II.

Conclusion:

Baseline VEGF and CEA levels were treatment-independent prognostic biomarkers for PFS and OS in both the studies.     

Bevacizumab and daily temozolomide for recurrent glioblastoma

BACKGROUND:

The authors performed a phase 2 trial of combined protracted daily temozolomide and biweekly bevacizumab for patients with recurrent glioblastoma who had previously received radiation therapy and temozolomide.

METHODS:

There was no limit on the number of previous disease progressions or previous regimens allowed. Thirty‐two adult patients were enrolled. Patients received temozolomide 50 mg/m² daily and bevacizumab 10 mg/kg intravenously every 14 days. Patients underwent physical examination and brain magnetic resonance imaging every 8 weeks.

RESULTS:

The authors observed a 6‐month progression‐free survival (PFS) rate of 18.8% (95% confidence interval [CI], 7.6%‐33.7%) and a median PFS of 15.8 weeks. The median overall survival (OS) was 37 weeks, the 6‐month OS rate was 62.5% (95% CI, 43.5%‐76.7%), and the 12‐month OS rate was 31.3% (95% CI, 16.4%‐47.3%). Nine patients (28%) had a radiographic response, and 7 patients (22%) had disease progression within the first 8 weeks of treatment. Patterns of progression were available for 21 patients. The authors observed that 52% of patients (n = 11) progressed locally, 38% (n = 8) progressed with a diffuse pattern, and 10% (n = 2) progressed at a distant site. Two patients discontinued therapy secondary to toxicity (prolonged thrombocytopenia and grade 4 pancreatitis). One patient experienced grade 5 pneumonia.

CONCLUSIONS:

The current study demonstrated that a regimen of combined daily temozolomide and biweekly bevacizumab had some activity and was well tolerated. However, the results obtained in this study were inferior to those observed in studies of bevacizumab monotherapy and of combined irinotecan and bevacizumab therapy. The current patient population was more heterogeneous and was pretreated more heavily than patients in previous studies. Cancer 2012;. © 2011 American Cancer Society.     

Biomarkers of angiogenesis and their role in the development of VEGF inhibitors

Vascular endothelial growth factor (VEGF) has been confirmed as an important therapeutic target in randomised clinical trials in multiple disease settings. However, the extent to which individual patients benefit from VEGF inhibitors is unclear. If we are to optimise the use of these drugs or develop combination regimens that build on this efficacy, it is critical to identify those patients who are likely to benefit, particularly as these agents can be toxic and are expensive. To this end, biomarkers have been evaluated in tissue, in circulation and by imaging. Consistent drug-induced increases in plasma VEGF-A and blood pressure, as well as reductions in soluble VEGF-R2 and dynamic contrast-enhanced MRI parameters have been reported. In some clinical trials, biomarker changes were statistically significant and associated with clinical end points, but there is considerable heterogeneity between studies that are to some extent attributable to methodological issues. On the basis of observations with these biomarkers, it is now appropriate to conduct detailed prospective studies to define a suite of predictive, pharmacodynamic and surrogate response biomarkers that identify those patients most likely to benefit from and monitor their response to this novel class of drugs.     

Bevacizumab-based therapy in relapsed glioblastoma: rationale and clinical experience to date

Relapsed glioblastoma (GBM) has an extremely poor prognosis and remains an invariably fatal disease, with a median overall survival of 6–7 months. Despite numerous clinical trials over the past 20–30 years, treatment options for relapsed GBM remain limited. In recent years, significant research efforts have focused on the use of antiangiogenic therapies for the treatment of GBM. Bevacizumab is a humanized monoclonal antibody that specifically inhibits the proangiogenic VEGF, with well-established clinical efficacy in a number of solid malignancies, which is now under investigation for the treatment of GBM. In this review, we discuss the available data regarding bevacizumab-based therapy in relapsed GBM, highlighting its potential and ongoing challenges in this difficult-to-treat disease.     

Phase 2 study of carboplatin, irinotecan, and bevacizumab for recurrent glioblastoma after progression on bevacizumab therapy

BACKGROUND:

The efficacy of carboplatin, irinotecan, and bevacizumab among recurrent glioblastoma (GBM) patients after prior progression on bevacizumab therapy in a phase 2, open‐label, single‐arm trial was evaluated.

METHODS:

Eligible patients received carboplatin (area under the plasma curve [AUC] 4 mg/ml‐min) on day 1, whereas bevacizumab (10 mg/kg) and irinotecan (340 mg/m² for patients on CYP3A enzyme‐inducing anti‐epileptics [EIAEDs] and 125 mg/m² for patients not on EIAEDs) were administered on days 1 and 14 of every 28‐day cycle. Patients were evaluated after each of the first 2 cycles and then after every other cycle. Treatment continued until progressive disease, unacceptable toxicity, noncompliance, or voluntary withdrawal. The primary end point was progression‐free survival at 6 months (PFS‐6), and secondary end points included safety and median overall survival (OS).

RESULTS:

All patients had progression on at least 1 prior bevacizumab regimen and 56% enrolled after either second or third overall progression. The median OS was 5.8 months (95% confidence interval [CI], 4.0‐7.0 months) and PFS‐6 rate was 16% (95% CI, 5.0%‐32.5%). The most common grade 3 or 4 events were hematologic and occurred in 29% of cycles. Nine patients (38%) required dose modification. There were no treatment‐related deaths.

CONCLUSIONS:

Carboplatin, irinotecan, and bevacizumab was associated with modest activity and adequate safety among recurrent GBM patients who progressed on bevacizumab previously. Cancer 2011;. © 2011 American Cancer Society.     

Angiogenesis and vascular targeting in Ewing sarcoma

Ewing sarcoma is the second most common type of bone cancer in children and young adults. In recent years, the mechanisms by which these tumors develop and maintain their vascular supply have been elucidated. Additional work has demonstrated that inhibition of angiogenic pathways or disruption of established vasculature can attenuate the growth of Ewing sarcoma mouse xenografts. Early clinical data suggest that these results also may extend to patients with Ewing sarcoma who are treated with antiangiogenic or antivascular therapies. For the current review, the authors summarized the available data supporting this approach. Cancer 2010. © 2009 American Cancer Society.     

Medulloblastoma: need for targeted treatment

The established role of VEGF signaling in promoting tumor angiogenesis has led to the development and clinical validation of several agents that selectively target this pathway in patients with advanced-stage malignancies. These include neutralizing anti-VEGF monoclonal antibodies, soluble VEGF receptors and small-molecule inhibitors of VEGF receptor function, administered either as monotherapy or in combination with chemotherapy. Several modes of action have been identified, such as inhibition of new vessel growth, regression of newly formed vasculature, alteration of tumor vessel function and direct effects on tumor cells. VEGF-targeting drugs currently play an important role in the treatment of cancer and their impact will probably further increase in the future.     

Editor's choice: Current status and future directions of anti-angiogenic therapy for gliomas

Molecular targets for the pathological vasculature are the vascular endothelial growth factor (VEGF)/VEGF receptor axis, integrins, angiopoietins, and platelet-derived growth factor receptor (PDGFR), as well as several intracellular or downstream effectors like protein kinase C beta and mammalian target of rapamycin (mTOR). Besides hypoxic damage or tumor cell starvation, preclinical models imply vessel independent tumor regression and suggest differential effects of anti-angiogenic treatments on tumorous and nontumorous precursor cells or the immune system. Despite compelling preclinical data and positive data in other cancers, the outcomes of clinical trials with anti-angiogenic agents in gliomas by and large have been disappointing and include VEGF blockage with bevacizumab, integrin inhibition with cilengitide, VEGF receptor inhibition with sunitinib or cediranib, PDGFR inhibition with imatinib or dasatinib, protein kinase C inhibition with enzastaurin, and mTOR inhibition with sirolimus, everolimus, or temsirolimus. Importantly, there is a lack of real understanding for this negative data. Anti-angiogenic therapies have stimulated the development of standardized imaging assessment and the integration of functional MRI sequences into daily practice. Here, we delineate directions in the identification of molecularly or image-based defined subgroups, anti-angiogenic cotreatment for immunotherapy, and the potential of ongoing trials or modified targets to change the game.     

Chimeric Mouse model to track the migration of bone marrow derived cells in glioblastoma following anti-angiogenic treatments

Bone marrow derived cells (BMDCs) have been shown to contribute in the tumor development. In vivo animal models to investigate the role of BMDCs in tumor development are poorly explored. We established a novel chimeric mouse model using as low as 5 × 10⁶ GFP+ BM cells in athymic nude mice, which resulted in >70% engraftment within 14 d. In addition, chimera was established in NOD-SCID mice, which displayed >70% with in 28 d. Since anti-angiogenic therapies (AAT) were used as an adjuvant against VEGF-VEGFR pathway to normalize blood vessels in glioblastoma (GBM), which resulted into marked hypoxia and recruited BMDCs to the tumor microenvironment (TME). We exploited chimeric mice in athymic nude background to develop orthotopic U251 tumor and tested receptor tyrosine kinase inhibitors and CXCR4 antagonist against GBM. We were able to track GFP+ BMDCs in the tumor brain using highly sensitive multispectral optical imaging instrument. Increased tumor growth associated with the infiltration of GFP+ BMDCs acquiring suppressive myeloid and endothelial phenotypes was seen in TME following treatments. Immunofluorescence study showed GFP+ cells accumulated at the site of VEGF, SDF1 and PDGF expression, and at the periphery of the tumors following treatments. In conclusion, we developed a preclinical chimeric model of GBM and phenotypes of tumor infiltrated BMDCs were investigated in context of AATs. Chimeric mouse model could be used to study detailed cellular and molecular mechanisms of interaction of BMDCs and TME in cancer.     

Nonsurgical treatment of recurrent glioblastoma

Standard treatment for glioblastoma multiforme is surgery followed by radiotherapy and chemotherapy, generally with temozolomide. However, disease recurs in almost all patients. Diagnosis of progression is complex given the possibility of pseudoprogression.The Response Assessment in Neuro-Oncology criteria increase the sensitivity for detecting progression. Most patients will not be candidates for new surgery or re-irradiation, and anticancer drugs are the most common approach for second-line treatment, if the patient’s condition allows. Antiangiogenics, inhibitors of the epidermal growth factor receptor, nitrosoureas, and re-treatment with temozolomide have been studied in the second line, but a standard therapy has not yet been established. This review considers currently available medical treatment options for patients with glioblastoma recurrence.     

Angiogenesis in myelodysplastic syndromes

It is now well established that solid tumour growth depends on angiogenesis. However, less is known about the generation of new vessels in haematological malignancies and, in particular, in preleukaemic-myelodysplastic syndromes (MDS). In this study, bone marrow microvessel density (MVD) was assessed by immunohistochemistry and compared in trephine biopsies from 14 controls, five infectious disease (ID), 82 MDS, 15 acute myeloid leukaemia (AML) and 14 myeloproliferative disorder (MPD) patients. Statistical analysis (P < 0.001) demonstrated that MDS MVD was higher than in controls and ID (21 +/- 9 vs 6 +/- 2 and 10 +/- 8 respectively) but lower than AML (30 +/- 12) and MPD (40 +/- 12). Among MDS-FAB subtypes, MVD was significantly higher in RAEB-t, CMML and fibrosis subsets compared to RA, RARS and RAEB subsets (P= 0.008). To further investigate angiogenesis machinery, the expression of vascular endothelial growth factor (VEGF) was evaluated by means of immunohistochemistry in control, MDS, AML and MPD biopsies. Even though VEGF mRNA expression was reported in the past in AML cell cultures and cell lines, in our samples VEGF expression was found to be particularly strong in most of the megakaryocytes but significantly less prominent in other cell populations including blasts. Since our findings suggest a correlation between angiogenesis and progression to leukaemia, additional work is now warranted to determine what regulates the generation of new vessels in MDS and leukaemia.     

Bevacizumab and glioblastoma: Scientific review,newly reported updates,and ongoing controversies

Anti‐angiogenic therapy for glioblastoma has been in the spotlight for several years, as researchers and clinicians strive to find agents with meaningful efficacy against glioblastoma. Bevacizumab in particular, in the second half of the last decade, became the most significant breakthrough in anti‐glioblastoma therapy since temozolomide. Optimism for bevacizumab has been somewhat challenged given recent clinical trials that have raised questions regarding its clinical effectiveness, the optimal timing of its use and the validity of endpoints, among other issues. In addition, uncertainty has recently arisen regarding the effects of bevacizumab on quality of life and neurocognitive function, two key clinical endpoints of unquestionable significance among glioblastoma patients. In this review, we highlight these controversies and other recent work related to bevacizumab for glioblastoma. Cancer 2015;121:997–1007. © 2014 American Cancer Society.     

Angiogenesis in Acute and Chronic Leukemias

Angiogenesis plays a key role in the growth of solid tumors. More recently, accumulating evidence has linked angiogenesis to the pathophysiology of leukemias. Different investigators have shown evidence of increased angiogenesis in the bone marrows of patients with acute and chronic leukemias. Elevated levels of angiogenic factors have also been reported in leukemic patients. A potential role for VEGF as an autocrine growth factor in AML has been suggested. Studies on the role of angiogenesis and VEGF as prognostic factors in leukemia require confirmation. The role of angiogenesis inhibitors in the treatment of leukemia is currently under investigation.     

Angiogenesis and melanoma - from basic science to clinical trials

The effective management of malignant melanoma has remained centred around the surgeon. The arrival of anti-angiogenic agents as the 'fourth' cancer treatment joining the ranks of surgery, chemotherapy and radiotherapy has been a source of renewed hope. This article provides an up-to-date review of the focus, state and rationale of clinical trials of anti-angiogenic therapies in metastatic malignant melanoma. Vascular Endothelial Growth Factor (VEGF) is by no means the only target, although perhaps the most extensively studied following the successful introduction of the anti-VEGF Antibody bevacizumab. This has been combined with other established therapies to try and improve outcomes in metastatic disease, and is being trialled in the UK to prevent metastasis in high-risk patients. We describe the encouraging preclinical work that lead to great enthusiasm for these agents, assess the key trials and their outcomes, discuss why these therapies have not revolutionised melanoma care and explore how they might be better targeted in the future.     

Activity of Angiogenesis Inhibitors in Metastatic Epithelioid Hemangioendothelioma: A Case Report

This report describes a patient with metastatic epithelioid hemangioendothelioma treated with bevacizumab and nanoparticle albumin-bound paclitaxel.The treatment was well tolerated and led to the stabilization of an aggressive variant of the disease. This case report is the first one that describes the activity of the combination of chemotherapy and bevacizumab in epithelioid hemangioendothelioma.Literature describing the activity of bevacizumab and other agents(thalidomide,lenalidomide,and interferon) believed to possess anti-angiogenic activities is also reviewed.     

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

Background:

The identification of molecular and genetic markers to predict or monitor the efficacy of bevacizumab (BV) represents a key issue in the treatment of metastatic colorectal cancer (mCRC).

Methods:

Plasma levels of vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble VEGF receptor 2 (sVEGFR-2) and thrombospondin-1 (TSP-1) were assessed by ELISA assay at different time points in a cohort of 25 patients enroled in a phase II trial of GONO-FOLFOXIRI plus BV as first-line treatment of mCRC. VEGF: −2578A/C, −1498C/T, −1154A/G, −634C/G and 936C/T; and VEGFR-2: −604A/G, +1192C/T and +1719A/T, polymorphisms were assessed in a total of 54 patients.

Results:

Treatment with GONO-FOLFOXIRI plus BV determined a prolonged and significant reduction in plasma free, biologically active VEGF concentration. Interestingly, VEGF concentrations remained lower than at baseline also at the time of PD. Conversely, PlGF levels increased during the treatment if compared with baseline, suggesting a possible role in tumour resistance; moreover, sVEGFR-2 increased at the time of PD, as well as TSP-1. No association of assessed polymorphisms with outcome was found.

Conclusion:

Our study suggested the possible mechanisms of resistance to combined therapy in those patients with a progressive disease to be tested in ongoing phase III randomised studies.     

Neuropilin is a Mediator of Angiogenesis

Neuropilin is both a receptor for semaphorins, which are mediators of neuronal guidance, and for VEGF, an angiogenesis factor. While the function of neuropilin in the nervous system has been characterized, its role in angiogenesis is only beginning to be elucidated. This article reviews some of the structural and functional features of neuropilin and presents the experimental evidence showing that it is a mediator of angiogenesis. In particular, we show that neuropilin and its soluble isoforms regulate tumor angiogenesis and subsequent tumor growth