North central cancer treatment group (NCCTG) N0537: phase II trial of VEGF-trap in patients with metastatic breast cancer previously treated with an anthracycline and/or a taxane

Theranostic role of 89Zr- and 177Lu-labeled aflibercept in breast cancer

PURPOSE

Triple-negative breast cancer (TNBC) has a poor prognosis due to the absence of effective therapeutic targets. Vascular endothelial growth factor (VEGF) family are expressed in 30-60% of TNBC, therefore providing potential therapeutic targets for TNBC. Aflibercept (Abe), a humanized recombinant fusion protein specifically bound to VEGF-A, B and placental growth factor (PIGF), has proven to be effective in the treatment in some cancers. Therefore, 89Zr/177Lu-labeled Abe was investigated for its theranostic role in TNBC.

METHODS

Abe was radiolabeled with 89Zr and 177Lu via the conjugation of chelators. Flow cytometry and cell immunofluorescent staining were performed to evaluate the binding affinity of Abe. Sequential PET imaging and fluorescent imaging were conducted in TNBC tumor bearing mice following the injection of 89Zr-labeled Abe and Cy5.5-labeled Abe. Treatment study was performed after the administration of 177Lu-labeled Abe. Tumor volume and survival were monitored and SPECT imaging and biodistribution studies were conducted. Safety evaluation was performed including body weight, blood cell measurement, and hematoxylin-eosin (H&E) staining of major organs. Expression of VEGF and CD31 was tested by immunohistochemical staining. Dosimetry was estimated using the OLINDA software.

RESULTS

FITC-labeled Abe showed a strong binding affinity to VEGF in TNBC 4T1 cells and HUVECs by flow cytometry and cell immunofluorescence. Tumor uptake of 89Zr-labeled Abe peaked at 120 h (SUVmax = 3.2 ± 0.64) and persisted before 168 h (SUVmax = 2.54 ± 0.42). The fluorescence intensity of the Cy5.5-labeled Abe group surpassed that of the Cy5.5-labeled IgG group, implying that Cy5.5-labeled Abe is a viable candidate monitoring in vivo tumor targeting and localization. 177Lu-labeled Abe (11.1 MBq) served well as the therapeutic component to suppress tumor growth with standardized tumor volume at 16 days, significantly smaller than PBS group (about 815.66 ± 3.58% vs 3646.52 ± 11.10%, n = 5, P < 0.01). Moreover, SPECT images confirmed high contrast between tumors and normal organs, indicating selective tumor uptake of 177Lu-labeled Abe. No discernible abnormalities in blood cells, and no evident histopathological abnormality observed in liver, spleen, and kidney. Immunohistochemical staining showed that 177Lu-labeled Abe effectively inhibited the expression of VEGF and CD31 of tumor, suggesting that angiogenesis may be suppressed by 177Lu-labeled Abe. The whole-body effective dose for an adult human was estimated to be 0.16 mSv/MBq.

CONCLUSION

89Zr/177Lu-labeled Abe could be a TNBC-specific marker with diagnostic value and provide insights into targeted therapy in the treatment of TNBC. Further clinical evaluation and translation may be of high significance for TNBC.

Risk of antiangiogenic adverse events in metastatic colorectal cancer patients receiving aflibercept in combination with chemotherapy: A meta-analysis

BACKGROUND

Aflibercept has been approved for the treatment of metastatic colorectal cancer for more than a decade, but its antiangiogenesis adverse effect profile during treatment remains unclear. This study is conducted to systematically review the risk of antiangiogenic adverse events in patients with metastatic colorectal cancer receiving aflibercept plus chemotherapy.

METHODS

We searched databases, including PubMed, Embase and the Cochrane Library up to September 9, 2021. Relevant randomized controlled trials (RCTs) and single-arm studies were included in the review. Statistical analyses were performed using R to calculate the summary incidence rate of antiangiogenic-related adverse events, odds ratios and 95% CIs. Heterogeneity among the included studies was assessed by subgroup analysis. Publication bias analysis and sensitivity analysis were performed to confirm the reliability of the results.

RESULTS

A total of 2889 patients from 10 studies met the inclusion criteria. The quality of the included studies was evaluated as qualified for further quantitative synthesis. In part of single-arm studies, the occurrence rates were 44.2% (95%CI, 39.7-48.7%) for hypertension, 31.3% (95% CI, 19.3-43.3%) for proteinuria, 27.3% (95%CI, 21.2-33.4%) for epistaxis, 22.5% (95%CI, 7.8-37.3%) for hemorrhage events, 8.0% (95%CI, 2.0-14 .0%) for venous thromboembolic event in all grades and 22.6% (95%CI, 19.1-26.2%) for grade III/IV hypertension, 7.4% (95%CI, 6.2-8.5%) for grade III/IV proteinuria. In part of RCT, compared to its counterpart, aflibercept containing arm was associated with the increased incidence rate in hypertension (OR:6.30, 95%CI: 3.49-11.36), proteinuria (OR:4.12, 95%CI: 1.25-13.61), epistaxis (OR:3.71, 95%CI: 2.84-4.85), III/IV hypertension (OR:7.20, 95%CI: 5.23-9.92), III/IV proteinuria (OR:5.13, 95%CI: 3.13-8.41). The funnel plot, Begg test and Egger test were carried out on the primary endpoints, III/IV hypertension rate and III/IV proteinuria rate, the result of which detected no obvious publication bias. No significant difference was observed in subgroup analysis in the primary endpoint between the subgroups stratified by treatment line (firstline or non-firstline), chemotherapy regime (FOLFIRI or others) and study design (RCTs or single-arm trials).

CONCLUSION

The available evidence suggests that using aflibercept is associated with an increased risk of antiangiogenic adverse events compared with controls. Further studies are needed to investigate this association. In the appropriate clinical scenario, the use of aflibercept in its approved indications remains justified. However, the results of this study should be interpreted with caution, as some of the evidence comes from single-arm clinical trials.

New potential beneficial effects of actein, a triterpene glycoside isolated from Cimicifuga species, in breast cancer treatment

Actein is a triterpene glycoside isolated from the rhizomes of Cimicifuga foetida (Chinese herb “shengma”) which could inhibit the growth of breast cancer cells. Nevertheless, the effect of actein on angiogenesis, which is an essential step for tumor growth and metastasis, has never been reported. Hence, this study aimed to investigate the in vitro and in vivo effects of actein on angiogenesis using human microvascular endothelial cells (HMEC-1), matrigel plug and tumor-bearing mouse models. Our results showed that actein significantly inhibited the proliferation, reduced the migration and motility of endothelial cells, and it could suppress the protein expressions of VEGFR1, pJNK and pERK, suggesting that JNK/ERK pathways were involved. In vivo results showed that oral administration of actein at 10 mg/kg for 7 days inhibited blood vessel formation in the growth factor-containing matrigel plugs. Oral actein treatments (10–15 mg/kg) for 28 days resulted in decreasing mouse 4T1 breast tumor sizes and metastasis to lungs and livers. The apparent reduced angiogenic proteins (CD34 and Factor VIII) expressions and down-regulated metastasis-related VEGFR1 and CXCR4 gene expressions were observed in breast tumors. Our novel findings provide insights into the use of actein for development of anti-angiogenic agents for breast cancer.

Cell-specific biomarkers and targeted biopharmaceuticals for breast cancer treatment

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

Incidence and risk of severe infections associated with aflibercept in cancer patients: a systematic review and meta-analysis

AIMS

Aflibercept is an engineered humanized vascular endothelial growth factor (VEGF)-targeted agent. Severe infections are serious adverse event associated with aflibercept. However, the contribution of aflibercept to infection is still unknown. We thus conducted this meta-analysis to investigate the overall incidence and risk of developing severe infections in cancer patients treated with aflibercept.

METHODS

Electronic databases including PubMed, Embase and abstracts presented at American Society of Clinical Oncology (ASCO) and European Society of Medical Oncology (ESMO) meeting were searched. Eligible studies were phase II and III prospective clinical trials of aflibercept in cancer patients with toxicity profile on infections. Summary incidences, relative risk (RR), odds ratio (OR) and 95% confidence intervals (95% CIs) were calculated by using either random effects or fixed effect models according to the heterogeneity of included studies.

RESULTS

A total of 4310 patients with a variety of solid tumours from 10 prospective clinical trials were included in the meta-analysis. The incidence of high grade infections associated with aflibercept was 7.3% (95% CI 4.3, 12.0%), with a mortality of 2.2% (95% CI 1.5, 3.1%). In addition, patients treated with aflibercept had a significantly increased risk of developing high grade (RR 1.87, 95% CI 1.52, 2.30; P < 0.001) and fatal (OR 2.16, 95% CI 1.14, 4.11; P = 0.018) infections. No evidence of publication bias was observed. Furthermore, the risk of infections with aflibercept was substantially higher than bevacizumab.

CONCLUSIONS

Aflibercept is associated with a significant increased risk of developing severe infections in patients with solid tumours. Frequent clinical monitoring and appropriate management for infections should be emphasized during aflibercept treatment.

Novel antiangiogenic drugs for the management of breast cancer: new approaches for an old issue?

Since angiogenesis plays an important role in cancer growth, infiltration and metastasis, many agents targeting this pathway have been developed over the last decade. Antiangiogenic drugs interfere with this process and may inhibit neoplastic growth or induce tumor dormancy by blocking the expanding network of newly formed capillaries. Despite the initial promise, targeting angiogenesis in breast cancer has not reached major breakthroughs. Nevertheless, the immunologic role of VEGF deserves to be further explored. We aim to describe the biological mechanisms which underlie the role of angiogenesis in breast cancer carcinogenesis, to depict its contribution to the metastatic process and to review the most important clinical trials testing angiogenic inhibitors in breast cancer, including monoclonal antibodies and novel small molecules.

Incidence and risk of proteinuria with aflibercept in cancer patients: a meta-analysis

Background

Aflibercept is a human recombinant fusion protein with antiangiogenic effects that functions as a decoy receptor to bind vascular endothelial growth factor A. Proteinuria is one of its major adverse effects with a substantial variation in the incidence rate, and the overall risk of proteinuria has not been systematically studied. We performed a meta-analysis of published clinical trials to quantify the incidence and relative risk of proteinuria in cancer patients treated with aflibercept.

Methods

The electronic databases were searched, including PubMed, Embase, Cochrane databases, and ASCO (American Society of Clinical Oncology) abstracts. Eligible studies were phase II and III prospective clinical trials of cancer patients treated with aflibercept with toxicity data on proteinuria. Overall incidence rates, relative risk (RR), and 95% confidence intervals (CI) were calculated using fixed or random effects models depending on the heterogeneity of the included studies.

Results

A total of 4,596 patients with a variety of solid tumors from 16 prospective clinical trials were included for the meta-analysis. The overall incidences of all-grade and high-grade proteinuria in cancer patients were 33.9% (95% CI: 27.3–42.1%) and 7.9% (95% CI: 6.1–10.2%). The relative risks of proteinuria of aflibercept compared to control were increased for all-grade (RR = 1.41, 95% CI: 1.13–1.77) and high-grade (RR = 6.18, 95% CI: 3.78–10.12) proteinuria. The risk of developing all-grade and high-grade proteinuria with aflibercept was substantially higher than that of bevacizumab (all-grade: RR 1.85, 95% CI: 1.63–2.11; high-grade: RR 2.37, 95% CI: 1.84–3.05).

Conclusions

Aflibercept is associated with an increased risk of developing proteinuria. Appropriate monitoring and treatment is strongly recommended to prevent potential renal damage. Future studies are still needed to investigate the risk reduction and possible use of aflibercept in cancer patients.

[New targeted therapies in breast cancer]

Trastuzumab improves care of patients with HER2+ breast cancer and allows a major gain in terms of survival. T-DM1 and pertuzumab are two new treatments, which give very encouraging results in metastatic breast cancer. Their place in neo-adjuvant and adjuvant setting still remains to be defined. Bevacizumab have its place in metastatic breast cancer. In adjuvant setting, results are disappointing and in neo-adjuvant setting, we need more studies on subgroups, which can benefit more. Development of the PARP inhibitors was slowed down by recent negative results in metastatic breast cancer but studies continue with more targeted patient's. Finally, everolimus, inhibitor of mTOR, allows to by pass the hormono-resistance in metastatic phase. Its toxicity must be taken into account in particular in adjuvant setting.

Antiangiogenic treatment approaches in breast cancer

SUMMARY The term ‘breast cancer’, as it is understood today, comprises heterogeneous disease entities with major disparities in terms of underlying tumor biology, treatment options and outcome. Nonetheless, all breast cancer subtypes depend upon neovascularization for growth and metastatic spreading, indicating that antiangiogenic strategies may constitute a highly effective treatment approach. Currently, the only antiangiogenic agent approved for breast cancer treatment is bevacizumab, a humanized monoclonal antibody targeting VEGF-A. In combination with chemotherapy, bevacizumab improved outcomes in terms of progression-free survival and response rate in the first- and second-line palliative setting, while overall survival remained unchanged. This fact prompted the US FDA to withdraw their approval for bevacizumab in breast cancer, while approval was retained in Europe. Other antiangiogenic agents, such as sunitinib, sorafenib or aflibercept, were either of limited effectiveness in breast cancer or concerns were raised due to the high toxicity rates. In order to fully exploit the potential benefit of antiangiogenesis, the identification of reliable predictive markers is urgently warranted. This article reviews the data on antiangiogenic treatment approaches in breast cancer, with an emphasis on bevacizumab, and discusses potential future treatment options.

Antiangiogenic agents in advanced, persistent or recurrent endometrial cancer: a novel treatment option

The limited efficacy of endocrine therapy and chemotherapy has stimulated several researches aimed to detect novel molecularly target therapies for advanced, persistent or recurrent endometrial cancer. Prior attempts to block vascular endothelial growth factor (VEGF) with sunitinib, sorafenib and thalidomide have obtained disappointing results. Bevacizumab has shown a promising activity in a phase II study. The percentages of patients with progression-free survival ≥6 months were similar for endometrioid (35%) and serous carcinoma (36%), but the number of cases was too small to assess the relevance of histological type for response to bevacizumab. In a phase II study, aflibercept was administered every 2 weeks to women with recurrent or persistent disease after chemotherapy. Forty-one percent of the patients were progression-free at 6 months, but 32% of the women had been removed from study because of toxicity. The detection of activating mutations of Fibroblast Growth Factor Receptor (FGFR)-2 in primary endometrial carcinoma has generated a new avenue for the development of molecularly target agents. Dovitinib, a tyrosine kinase inhibitor targeting both VEGF receptor (VEGFR) and FGFRs, is under clinical investigation in different malignancies including endometrial cancer.

A two-compartment model of VEGF distribution in the mouse

Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis – the growth of new microvessels from existing microvasculature. Angiogenesis is a complex process involving numerous molecular species, and to better understand it, a systems biology approach is necessary. In vivo preclinical experiments in the area of angiogenesis are typically performed in mouse models; this includes drug development targeting VEGF. Thus, to quantitatively interpret such experimental results, a computational model of VEGF distribution in the mouse can be beneficial. In this paper, we present an in silico model of VEGF distribution in mice, determine model parameters from existing experimental data, conduct sensitivity analysis, and test the validity of the model.

The multiscale model is comprised of two compartments: blood and tissue. The model accounts for interactions between two major VEGF isoforms (VEGF₁₂₀ and VEGF₁₆₄) and their endothelial cell receptors VEGFR-1, VEGFR-2, and co-receptor neuropilin-1. Neuropilin-1 is also expressed on the surface of parenchymal cells. The model includes transcapillary macromolecular permeability, lymphatic transport, and macromolecular plasma clearance. Simulations predict that the concentration of unbound VEGF in the tissue is approximately 50-fold greater than in the blood. These concentrations are highly dependent on the VEGF secretion rate. Parameter estimation was performed to fit the simulation results to available experimental data, and permitted the estimation of VEGF secretion rate in healthy tissue, which is difficult to measure experimentally. The model can provide quantitative interpretation of preclinical animal data and may be used in conjunction with experimental studies in the development of pro- and anti-angiogenic agents. The model approximates the normal tissue as skeletal muscle and includes endothelial cells to represent the vasculature. As the VEGF system becomes better characterized in other tissues and cell types, the model can be expanded to include additional compartments and vascular elements.

Antiangiogenic therapy for breast cancer

Angiogenesis is an important component of cancer growth, invasion and metastasis. Therefore, inhibition of angiogenesis is an attractive strategy for treatment of cancer. We describe existing clinical trials of antiangiogenic agents and the challenges facing the clinical development and optimal use of these agents for the treatment of breast cancer. Currently, the most promising approach has been the use of bevacizumab, a humanized monoclonal antibody directed against the most potent pro-angiogenic factor, vascular endothelial growth factor (VEGF). Small molecular inhibitors of VEGF tyrosine kinase activity, such as sorafenib, appear promising. While, the role of sunitinib and inhibitors of mammalian target of rapamycin (mTOR) in breast cancer has to be defined. Several unanswered questions remain, such as choice of drug(s), optimal duration of therapy and patient selection criteria.

Angiogenesis inhibitors: current strategies and future prospects

Angiogenesis has become an attractive target for drug therapy because of its key role in tumor growth. An extensive array of compounds is currently in preclinical development, with many now entering the clinic and/or achieving approval from the US Food and Drug Administration. Several regulatory and signaling molecules governing angiogenesis are of interest, including growth factors (eg, vascular endothelial growth factor, platelet-derived growth factor, fibroblast growth factor, and epidermal growth factor), receptor tyrosine kinases, and transcription factors such as hypoxia inducible factor, as well as molecules involved in mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) signaling. Pharmacologic agents have been identified that target these pathways, yet for some agents (notably thalidomide), an understanding of the specific mechanisms of antitumor action has proved elusive. The following review describes key molecular mechanisms and novel therapies that are on the horizon for antiangiogenic tumor therapy.