Long-term response to first-line bevacizumab-based therapy in patients with metastatic breast cancer: results of the observational "LORENA" study

Front-Line Bevacizumab plus Chemotherapy with or without Maintenance Therapy for Metastatic Breast Cancer: An Observational Study by the Hellenic Oncology Research Group

Front-line bevacizumab (BEV) in combination with taxanes offers benefit in progression-free survival (PFS) in metastatic breast cancer (mBC). The medical records of mBC patients, treated with front-line BEV-based chemotherapy, were retrospectively reviewed in order to generate real life safety and efficacy data. Patients with human epidermal growth factor receptor 2 (HER2)-negative mBC treated with front-line BEV in combination with chemotherapy were eligible. Maintenance therapy with BEV and/or hormonal agents was at the physicians’ discretion. Among the 387 included patients, the most common adverse events were anemia (61.9%, mainly grade 1), grade 3/4 neutropenia (16.5%), grade 1/2 fatigue (22.3%), and grade 1/2 neuropathy (19.6%). Dose reductions were required in 164 cycles (7.1%) and toxicity led to treatment discontinuation in 21 patients (5.4%). The median PFS and the median overall survival (OS) were 13.3 (95% CI: 11.7–14.8) and 32.3 months (95% CI: 27.7–36.9), respectively. Maintenance therapy, with hormonal agents (ET) and/or BEV, was associated with longer OS versus no maintenance therapy (47.2 versus 23.6 months; p < 0.001) in patients with hormone receptor (HR)-positive disease and BEV maintenance offered longer OS versus no maintenance in patients with HR-negative disease (52.8 versus 23.3; p = 0.023). These real-life data show that front-line BEV-based chemotherapy in HER2-negative mBC patients is an effective treatment with an acceptable toxicity profile. The potential benefit of maintenance treatment, especially ET, is important and warrants further research.

Prognostic Factors in Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative (HR+/HER2-) Advanced Breast Cancer: A Systematic Literature Review

PURPOSE

Advanced breast cancer is a heterogeneous disease with several well-defined subtypes, among which, hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) is most prevalent. Determination of HR and HER2 status influences prognosis and, thus, disease management. Although literature on these prognostic factors exist, especially in the early breast cancer setting, it remains unclear to what extent these factors can guide clinical decision-making in the advanced disease setting. Therefore, we sought to identify the strength and consistency of evidence for prognostic factors in patients with HR+/HER2- advanced breast cancer.

METHODS

A systematic literature review (SLR) of the major electronic databases was conducted in November 2018 for primary research studies published since 2010. Endpoints of interest were tumor response, progression-free survival (PFS), overall survival (OS), and breast cancer-specific survival (BCSS).

RESULTS

Seventy-nine studies were included wherein all patients were diagnosed with advanced breast cancer and ≥50% of the population were HR+/HER2-. OS was the most commonly assessed endpoint (n=67) followed by PFS (n=33), BCSS (n=5) and tumor response (n=3). The prognostic factors with strongest evidence of association with worse OS were negative progesterone receptor status, higher tumor grade, higher circulating tumor cell (CTC) count and higher Ki67 level, number of metastatic sites (eg multiple vs single) and sites of metastases (eg presence of liver metastases vs absence), shorter time to recurrence or progression to advanced breast cancer, poor performance status, prior therapy attributes in the early or metastatic setting (type of therapy, treatment line, response of prior therapy), and race (black vs white). The prognostic factors that had strongest evidence of association with PFS included CTC count, number and sites of metastases, and absence of prior therapy or higher lines of therapy in the early or metastatic setting. The directionality of association was consistent for all prognostic factors except between lymph node and OS, and de novo metastatic breast cancer and PFS.

CONCLUSION

Multiple disease, treatment, and patient-related prognostic factors impact survival, particularly OS, in patients with HR+/HER2- advanced breast cancer. Treatment outcomes can vary considerably due to these factors. Understanding poorer prognostic factors for patients can result in improved clinical decision-making.

Endothelial nitric oxide synthase c.-813C>T predicts for proteinuria in metastatic breast cancer patients treated with bevacizumab-based chemotherapy

PURPOSE

To investigate the association between single nucleotide polymorphisms (SNPs) in endothelial nitric oxide synthase (eNOS) and interleukin-8 (IL-8) genes and risk of developing bevacizumab-related adverse events in metastatic breast cancer (mBC) patients.

PATIENTS AND METHODS

mBC patients candidate to receive bevacizumab-based chemotherapy were enrolled in this pharmacogenetic study. eNOS c.-813C>T and c.894G>T, and IL-8 c.-251A>T were analyzed by real time PCR on genomic DNA extracted from peripheral blood. Univariate analysis was performed to test the association between each SNP and treatment-related toxicities.

RESULTS

Seventy-six mBC patients were enrolled in the present study. Patients carrying the homozygous variant eNOS c.-813TT genotype showed a statistically significant occurrence of any grade proteinuria when compared to CT or CC genotypes (p = 0.004). No significant association of proteinuria with IL-8 SNP or hypertension with selected eNOS and IL-8 SNPs was found.

CONCLUSIONS

These findings suggest an association between the eNOS c.-813C>T polymorphism and the development of proteinuria in mBC patients receiving a bevacizumab-based chemotherapy.

Maintenance Therapy in HER2-Negative Metastatic Breast Cancer: A New Approach for an Old Concept

The aim of this article is to discuss the role of maintenance therapy with chemotherapy, endocrine therapy, or bevacizumab-based combination therapy in patients with human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer. The optimization of maintenance therapy in patients with HER2-negative metastatic breast cancer must be based on disease profile (tumor subtype and endocrine-sensitive status), the prior use of bevacizumab-containing regimens, and the number of prognostic risk factors. Chemotherapy should be used in patients with triple-negative breast cancer and endocrine-resistant hormone receptor-positive metastatic breast cancer, whereas endocrine therapy is the preferred option for patients with endocrine-sensitive hormone receptor-positive metastatic breast cancer. After first-line bevacizumab plus chemotherapy, bevacizumab may be continued until disease progression or unacceptable toxicity, and endocrine therapy or capecitabine may be added. The goals of maintenance therapy in patients with HER2-negative metastatic breast cancer are to improve and maintain clinical response, increase time to progression, extend overall survival, relieve tumor-related symptoms, and delay the use of aggressive therapies, without compromising quality of life. Maintenance therapy, using chemotherapy, endocrine therapy, and combined therapy with bevacizumab, is a reasonable strategy to achieve these goals in patients with either triple-negative breast cancer or hormone receptor-positive and HER2-negative metastatic breast cancer. Ongoing clinical studies of new molecular-targeted therapies may provide additional pharmacological options for future maintenance strategies in these patients.

Evaluating the effect of Avastin on breast cancer angiogenesis using synchrotron radiation

Background

The visualization of microvasculature is an essential step in understanding the mechanisms underlying early vessel disorders involved in breast cancer and for developing effective therapeutic strategies. However, generating detailed and reproducible data using immunohistochemistry analysis of breast cancer angiogenesis has been difficult.

Methods

To analyze the diversification of angiogenesis in the development of tumor growth and evaluate the anti-vascular effects of Avastin (bevacizumab), we used new X-ray microangiography and third-generation synchrotron radiation-based micro-computed tomography (SR micro-CT) technology. With these techniques, we were able to investigate the structures and density of microvessels in xenograft mouse models (n=24). Barium sulfate nanoparticles were injected into the left cardiac ventricle of the mice to allow the visualization of blood vessels.

Results

Three-dimensional structures of microvessels were displayed with a high spatial image resolution of 20-30 µm. The density of angiogenesis and the incidence of lung metastasis were significantly reduced in xenograft mouse models of breast cancer treated with Avastin compared with control groups. Also, the density of smaller vessels (diameter <50 µm) was significantly decreased in the Avastin-treated mice, while the density of larger vessels (diameter >100 µm) was not significantly changed.

Conclusions

Avastin inhibited tumor growth and lung metastasis by reducing microvessels. Additionally, synchrotron radiation (SR) techniques are useful as an additional tool for more precise quantification of angiogenesis.

Squalamine blocks tumor-associated angiogenesis and growth of human breast cancer cells with or without HER-2/neu overexpression

Angiogenesis is critical for breast cancer progression. Overexpression of HER-2/neu receptors occur in 25-30% of breast cancers, and treatment with trastuzumab inhibits HER-2-overexpressing tumor growth. Notably, HER-2-mediated signaling enhances vascular endothelial growth factor (VEGF) secretion to increase tumor-associated angiogenesis. Squalamine (aminosterol compound) suppresses VEGF-induced activation of kinases in vascular endothelial cells and inhibits tumor-associated angiogenesis. We assessed antitumor effects of squalamine either alone or with trastuzumab in nude mice bearing breast tumor xenografts without (MCF-7) or with HER2-overexpression (MCF-7/HER-2). Squalamine alone inhibited progression of MCF-7 tumors lacking HER2 overexpression, and squalamine combined with trastuzumab elicited marked inhibition of MCF-7/HER2 growth exceeding that of trastuzumab alone. MCF-7/HER-2 cells secrete higher levels of VEGF than MCF-7 cells, but squalamine elicited no growth inhibition of either MCF-7/HER-2 or MCF-7 cells in vitro. However, squalamine did stop growth of human umbilical vein endothelial cells (HUVECs) and reduced VEGF-induced endothelial tube-like formations in vitro. These effects correlated with blockade of focal adhesion kinase phosphorylation and stress fiber assembly in HUVECs. Thus, squalamine effectively inhibits growth of breast cancers with or without HER-2-overexpression, an effect due in part to blockade of tumor-associated angiogenesis.