Evaluating the addition of bevacizumab to endocrine therapy as first-line treatment for hormone receptor-positive metastatic breast cancer: a pooled analysis from the LEA (GEICAM/2006-11_GBG51) and CALGB 40503 (Alliance) trials

Targeting the crosstalk between estrogen receptors and membrane growth factor receptors in breast cancer treatment: Advances and opportunities

Estrogens play a critical role in the initiation and progression of breast cancer. Estrogen receptor (ER)α, ERβ, and G protein-coupled estrogen receptor are the primary receptors for estrogen in breast cancer. These receptors are mainly activated by binding with estrogens. The crosstalk between ERs and membrane growth factor receptors creates additional pathways that amplify the effects of their ligands and promote tumor growth. This crosstalk may cause endocrine therapy resistance in ERα-positive breast cancer. Furthermore, this may explain the resistance to anti-human epidermal growth factor receptor-2 (HER2) treatment in ERα-/HER2-positive breast cancer and chemotherapy resistance in triple-negative breast cancer. Accordingly, it is necessary to understand the complex crosstalk between ERs and growth factor receptors. In this review, we delineate the crosstalk between ERs and membrane growth factor receptors in breast cancer. Moreover, this review highlights the current progress in clinical treatment and discusses how pharmaceuticals target the crosstalk. Lastly, we discuss the current challenges and propose potential solutions regarding the implications of targeting crosstalk via pharmacological inhibition. Overall, the present review provides a landscape of the crosstalk between ERs and membrane growth factor receptors in breast cancer, along with valuable insights for future studies and clinical treatments using a chemotherapy-sparing regimen to improve patient quality of life.

Systemic therapy for hormone receptor-positive/human epidermal growth factor receptor 2-negative early stage and metastatic breast cancer

Hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer is defined by the presence of the estrogen receptor and/or the progesterone receptor and the absence of HER2 gene amplification. HR-positive/HER2-negative breast cancer accounts for 65%-70% of all breast cancers, and incidence increases with increasing age. Treatment varies by stage, and endocrine therapy is the mainstay of treatment in both early stage and late-stage disease. Combinations with cyclin-dependent kinase 4/6 inhibitors have reduced distant recurrence in the early stage setting and improved overall survival in the metastatic setting. Chemotherapy is used based on stage and tumor biology in the early stage setting and after endocrine resistance for advanced disease. New therapies, including novel endocrine agents and antibody-drug conjugates, are now changing the treatment landscape. With the availability of new treatment options, it is important to define the optimal sequence of treatment to maximize clinical benefit while minimizing toxicity. In this review, the authors first discuss the pathologic and molecular features of HR-positive/HER2-negative breast cancer and mechanisms of endocrine resistance. Then, they discuss current and emerging therapies for both early stage and metastatic HR-positive/HER2-negative breast cancer, including treatment algorithms based on current data.

The role of VEGF in cancer-induced angiogenesis and research progress of drugs targeting VEGF

Angiogenesis is a double-edged sword; it is a mechanism that defines the boundary between health and disease. In spite of its central role in physiological homeostasis, it provides the oxygen and nutrition needed by tumor cells to proceed from dormancy if pro-angiogenic factors tip the balance in favor of tumor angiogenesis. Among pro-angiogenic factors, vascular endothelial growth factor (VEGF) is a prominent target in therapeutic methods due to its strategic involvement in the formation of anomalous tumor vasculature. In addition, VEGF exhibits immune-regulatory properties which suppress immune cell antitumor activity. VEGF signaling through its receptors is an integral part of tumoral angiogenic approaches. A wide variety of medicines have been designed to target the ligands and receptors of this pro-angiogenic superfamily. Herein, we summarize the direct and indirect molecular mechanisms of VEGF to demonstrate its versatile role in the context of cancer angiogenesis and current transformative VEGF-targeted strategies interfering with tumor growth.

[Therapeutic strategies for the treatment of endocrine resistant hormone receptor positive advanced breast cancer]

HR+ breast cancers are defined by the prominence of signaling pathways dependent on the estrogen receptor. Endocrine therapy is the standard treatment for these advanced diseases. Resistance to these treatments, called hormone resistance, appears invariably with biological mechanisms that have led to the development of therapeutic opportunities. An exhaustive literature review was carried out concerning the biology of the hormone resistance pathways, the therapeutic options before the era of CDK4/6 inhibitors, the rise of CDK4/6 inhibitors and the therapeutic prospects in a situation of hormone resistance. Various biological abnormalities have been identified in the mechanisms of hormone resistance such as changes in the estrogen receptor, mutations in the ESR1 gene, aberrant activation of the PI3K pathway or cell cycle deregulations. Historical strategies for circumventing this hormone resistance have been based on hormonal manipulation, on the development of new endocrine therapy such as fulvestrant (selective estrogen receptor inhibitor, SERD), on combinations of treatments such as everolimus, a mTOR inhibitor. This strategy combining endocrine therapy and targeted therapy has led to the development of combinations with CDK4/6 inhibitors which have now become a standard treatment in the hormone resistance phase. The future of this therapeutic era remains to be written with new combinations of hormone therapy and targeted therapy such as PI3K inhibitors or even with the positioning of new SERDs in clinical development.

Targeting the formation of estrogens for treatment of hormone dependent diseases-current status

Local formation and action of estrogens have crucial roles in hormone dependent cancers and benign diseases like endometriosis. Drugs that are currently used for the treatment of these diseases act at the receptor and at the pre-receptor levels, targeting the local formation of estrogens. Since 1980s the local formation of estrogens has been targeted by inhibitors of aromatase that catalyses their formation from androgens. Steroidal and non-steroidal inhibitors have successfully been used to treat postmenopausal breast cancer and have also been evaluated in clinical studies in patients with endometrial, ovarian cancers and endometriosis. Over the past decade also inhibitors of sulfatase that catalyses the hydrolysis of inactive estrogen-sulfates entered clinical trials for treatment of breast, endometrial cancers and endometriosis, with clinical effects observed primarily in breast cancer. More recently, inhibitors of 17beta-hydroxysteroid dehydrogenase 1, an enzyme responsible for formation of the most potent estrogen, estradiol, have shown promising results in preclinical studies and have already entered clinical evaluation for endometriosis. This review aims to provide an overview of the current status of the use of hormonal drugs for the major hormone-dependent diseases. Further, it aims to explain the mechanisms behind the -sometimes- observed weak effects and low therapeutic efficacy of these drugs and the possibilities and the advantages of combined treatments targeting several enzymes in the local estrogen formation, or drugs acting with different therapeutic mechanisms.

Switch maintenance endocrine therapy plus bevacizumab after bevacizumab plus paclitaxel in advanced or metastatic oestrogen receptor-positive, HER2-negative breast cancer (BOOSTER): a randomised, open-label, phase 2 trial

BACKGROUND

Anticancer treatment regimens typically cause unpleasant side-effects. We aimed to investigate the benefit of switch maintenance endocrine therapy plus bevacizumab after fixed cycles of first-line induction chemotherapy with weekly paclitaxel plus bevacizumab in patients with oestrogen receptor (ER)-positive, HER2-negative advanced or metastatic breast cancer.

METHODS

BOOSTER was a prospective, open-label, multicentre, randomised, controlled, phase 2 study done in 53 hospitals in Japan. Eligible patients were women aged 20-75 years, with an Eastern Cooperative Oncology Group performance status of 0-1, who had not received chemotherapy for ER-positive, HER2-negative advanced or metastatic breast cancer. All patients received four to six cycles (in which 4 weeks of treatment constitute one cycle) of weekly paclitaxel plus bevacizumab induction therapy (weekly paclitaxel 90 mg/m2, administered intravenously on days 1, 8, and 15 of each cycle, plus bevacizumab 10 mg/kg administered intravenously on days 1 and 15 of each cycle; first registration). Patients with a complete response, partial response, or stable disease after induction therapy (responders) were then randomly assigned (1:1) using the randomisation enrolment form to either continue weekly paclitaxel plus bevacizumab or switch to maintenance endocrine therapy (an aromatase inhibitor or fulvestrant with or without ovarian-function suppression) plus bevacizumab. Randomisation was stratified by induction therapy period, response to induction therapy, age, history of endocrine therapy, and study site. Patients could receive weekly paclitaxel plus bevacizumab reinduction if they had disease progression with maintenance endocrine therapy plus bevacizumab. The primary endpoint was time to failure of strategy (TFS). Efficacy and safety analyses were done in all treated patients (full analysis set). This study is registered with ClinicalTrials.gov, NCT01989780, and registration and follow-up are closed.

FINDINGS

Between Jan 1, 2014, and Dec 31, 2015, we enrolled 160 patients who began weekly paclitaxel plus bevacizumab induction therapy. 125 (78%) patients (responders) were randomly assigned to endocrine therapy plus bevacizumab (n=62; n=61 in the full analysis set) or weekly paclitaxel plus bevacizumab (n=63; n=63 in the full analysis set). Among 61 patients in the switch maintenance endocrine therapy plus bevacizumab group, 32 (52%) were reinitiated on weekly paclitaxel plus bevacizumab. At a median follow-up of 21·3 months (IQR 13·0-28·2), TFS was significantly longer in the endocrine therapy plus bevacizumab group than in the weekly paclitaxel plus bevacizumab group (median 16·8 months [95% CI 12·9-19·0] vs 8·9 months [5·7-13·8]; hazard ratio 0·51 [0·34-0·75]; p=0·0006). The most common grade 3-4 non-haematological adverse events after randomisation were proteinuria (in ten [16%] of 61 patients in the endocrine therapy plus bevacizumab group vs eight [13%] of 63 patients in the weekly paclitaxel plus bevacizumab group), hypertension (six [10%] vs six [10%]), and peripheral neuropathy (one [2%] vs six [10%]). One treatment-related death was reported in the weekly paclitaxel plus bevacizumab group (duodenal ulcer perforation).

INTERPRETATION

Switch to maintenance endocrine therapy plus bevacizumab with the possibility of weekly paclitaxel reinduction if needed is an efficacious alternative, with a better safety profile, to continuing weekly paclitaxel plus bevacizumab in patients with ER-positive, HER2-negative advanced or metastatic breast cancer who have responded to induction therapy.

FUNDING

Chugai Pharmaceutical.

TRANSLATION

For the Japanese translation of the abstract see Supplementary Materials section.

Targeting Angiogenesis in Breast Cancer: Current Evidence and Future Perspectives of Novel Anti-Angiogenic Approaches

Angiogenesis is a vital process for the growth and dissemination of solid cancers. Numerous molecular pathways are known to drive angiogenic switch in cancer cells promoting the growth of new blood vessels and increased incidence of distant metastasis. Several angiogenesis inhibitors are clinically available for the treatment of different types of advanced solid cancers. These inhibitors mostly belong to monoclonal antibodies or small-molecule tyrosine kinase inhibitors targeting the classical vascular endothelial growth factor (VEGF) and its receptors. Nevertheless, breast cancer is one example of solid tumors that had constantly failed to respond to angiogenesis inhibitors in terms of improved survival outcomes of patients. Accordingly, it is of paramount importance to assess the molecular mechanisms driving angiogenic signaling in breast cancer to explore suitable drug targets that can be further investigated in preclinical and clinical settings. This review summarizes the current evidence for the effect of clinically available anti-angiogenic drugs in breast cancer treatment. Further, major mechanisms associated with intrinsic or acquired resistance to anti-VEGF therapy are discussed. The review also describes evidence from preclinical and clinical studies on targeting novel non-VEGF angiogenic pathways in breast cancer and several approaches to the normalization of tumor vasculature by targeting pericytes, utilization of microRNAs and extracellular tumor-associate vesicles, using immunotherapeutic drugs, and nanotechnology.

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.

Carboplatin-Cyclophosphamide or Paclitaxel without or with Bevacizumab as First-Line Treatment for Metastatic Triple-Negative Breast Cancer (BOOG 2013-01)

Background

The addition of bevacizumab to chemotherapy conferred a modest progression-free survival (PFS) benefit in metastatic triple-negative breast cancer (mTNBC). However, no overall survival (OS) benefit has been reported. Also, its combination with carboplatin-cyclophosphamide (CC) has never been investigated.

Methods

The Triple-B study is a multicenter, randomized phase IIb trial that aims to prospectively validate predictive biomarkers, including baseline plasma vascular endothelial growth factor receptor-2 (pVEGFR-2), for bevacizumab benefit. mTNBC patients were randomized between CC and paclitaxel (P) without or with bevacizumab (CC ± B or P ± B). Here we report on a preplanned safety and preliminary efficacy analysis after the first 12 patients had been treated with CC+B and on the predictive value of pVEGFR-2.

Results

In 58 patients, the median follow-up was 22.1 months. Toxicity was manageable and consistent with what was known for each agent separately. There was a trend toward a prolonged PFS with bevacizumab compared to chemotherapy only (7.0 vs. 5.2 months; adjusted HR = 0.60; 95% CI 0.33-1.08; p = 0.09), but there was no effect on OS. In this small study, pVEGFR-2 concentration did not predict a bevacizumab PFS benefit. Both the intention-to-treat analysis and the per-protocol analysis did not yield a significant treatment-by-biomarker test for interaction (p_interaction = 0.69).

Conclusions

CC and CC+B are safe first-line regimens for mTNBC and the side effects are consistent with those known for each individual agent. pVEGFR-2 concentration did not predict a bevacizumab PFS benefit.

Machine learning-based image analysis for accelerating the diagnosis of complicated preneoplastic and neoplastic ductal lesions in breast biopsy tissues

PURPOSE

Diagnosis of breast preneoplastic and neoplastic lesions is difficult due to their similar morphology in breast biopsy specimens. To diagnose these lesions, pathologists perform immunohistochemical analysis and consult with expert breast pathologists. These additional examinations are time-consuming and expensive. Artificial intelligence (AI)-based image analysis has recently improved, and may help in ordinal pathological diagnosis. Here, we showed the significance of machine learning-based image analysis of breast preneoplastic and neoplastic lesions for facilitating high-throughput diagnosis.

METHODS

Images were obtained from normal mammary glands, hyperplastic lesions, preneoplastic lesions and neoplastic lesions, such as usual ductal hyperplasia (UDH), columnar cell lesion (CCL), ductal carcinoma in situ (DCIS), and DCIS with comedo necrosis (comedo DCIS) in breast biopsy specimens. The original enhanced convoluted neural network (CNN) system was used for analyzing the pathological images.

RESULTS

The AI-based image analysis provided the following area under the curve values (AUC): normal lesion versus DCIS, 0.9902; DCIS versus comedo DCIS, 0.9942; normal lesion versus CCL, 0.9786; and UDH versus DCIS, 1.000. Multiple comparison analysis showed precision and recall scores similar to those of single comparison analysis. Based on the gradient-weighted class activation mapping (Grad-CAM) used to visualize the important regions reflecting the result of CNN analysis, the ratio of stromal tissue in the whole weighted area was significantly higher in UDH and CCL than that in DCIS.

CONCLUSIONS

These analyses may provide a more accurate and rapid pathological diagnosis of patients. Moreover, Grad-CAM identifies uncharted important histological characteristics for newer pathological findings and targets of research for understanding diseases.

Strategic Combinations to Prevent and Overcome Resistance to Targeted Therapies in Oncology

Recent advances in the understanding of underlying molecular signaling mechanisms of cancer susceptibility and progression have led to an increase in the use of targeted therapies for cancer treatment. Despite improvements in survival with new treatment options in oncology, resistance to therapy is a major obstacle to the long-term effectiveness of targeted agents in metastatic cancer treatment, culminating in insensitivity to treatment and tumor outgrowth. Adaptive resistance can play an important role in primary and upfront resistance to therapy as well as in secondary or acquired resistance. By focusing on colorectal and breast tumors, we discuss how therapeutic combinations based on specific drivers of tumor biology can be used to overcome resistance. We present how monitoring tumor dynamics over time may allow early adaptation of treatment. Breast cancer is the most common malignancy in women worldwide, and the majority of these cancers are sensitive to endocrine therapy (ET) blocking the production of or response to estrogen. However, primary and acquired resistance limits efficacy. Recent combinations of agents targeted to pathways that drive tumor growth resistance with ET have resulted in remarkable improvements in disease response and control, improving survival in some settings. In this review, we summarize adaptive resistance mechanisms, approaches to combination strategies, and dynamic tumor monitoring to improve efficacy and overcome resistance. We provide examples of combination therapy to enhance the efficacy of targeted therapies in breast and colorectal tumors.

TBCRC 002: a phase II, randomized, open-label trial of preoperative letrozole with or without bevacizumab in postmenopausal women with newly diagnosed stage 2/3 hormone receptor-positive and HER2-negative breast cancer

Background

In preclinical studies, the expression of vascular endothelial growth factor (VEGF) in hormone receptor-positive breast cancer is associated with estrogen-independent tumor growth and resistance to endocrine therapies. This study investigated whether the addition of bevacizumab, a monoclonal antibody against VEGF, to letrozole enhanced the antitumor activity of the letrozole in the preoperative setting.

Methods

Postmenopausal women with newly diagnosed stage 2 or 3 estrogen and/or progesterone receptor-positive, HER2-negative breast cancer were randomly assigned (2:1) between letrozole 2.5 mg PO daily plus bevacizumab 15 mg/kg IV every 3 weeks (Let/Bev) and letrozole 2.5 mg PO daily (Let) for 24 weeks prior to definitive surgery. Primary objective was within-arm pathologic complete remission (pCR) rate. Secondary objectives were safety, objective response, and downstaging rate.

Results

Seventy-five patients were randomized (Let/Bev n = 50, Let n = 25). Of the 45 patients evaluable for pathological response in the Let/Bev arm, 5 (11%; 95% CI, 3.7–24.1%) achieved pCR and 4 (9%; 95% CI, 2.5–21.2%) had microscopic residual disease; no pCRs or microscopic residual disease was seen in the Let arm (0%; 95% CI, 0–14.2%). The rates of downstaging were 44.4% (95% CI, 29.6–60.0%) and 37.5% (95% CI, 18.8–59.4%) in the Let/Bev and Let arms, respectively. Adverse events typically associated with letrozole (hot flashes, arthralgias, fatigue, myalgias) occurred in similar frequencies in the two arms. Hypertension, headache, and proteinuria were seen exclusively in the Let/Bev arm. The rates of grade 3 and 4 adverse events and discontinuation due to adverse events were 18% vs 8% and 16% vs none in the Let/Bev and Let arms, respectively. A small RNA-based classifier predictive of response to preoperative Let/Bev was developed and confirmed on an independent cohort.

Conclusion

In the preoperative setting, the addition of bevacizumab to letrozole was associated with a pCR rate of 11%; no pCR was seen with letrozole alone. There was additive toxicity with the incorporation of bevacizumab. Responses to Let/Bev can be predicted from the levels of 5 small RNAs in a pretreatment biopsy.

Trial registration

This trial is registered with ClinicalTrials.gov (Identifier: NCT00161291), first posted on September 12, 2005, and is completed.

Review of concepts in therapeutic decision-making in HER2-negative luminal metastatic breast cancer

Purpose

Hormone receptor (HR)-positive, Human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC) requires a therapeutic approach that takes into account multiple factors, with treatment being based on anti-estrogen hormone therapy (HT). As consensus documents are valuable tools that assist in the decision-making process for establishing clinical strategies and optimize the delivery of health services, this consensus document has been created with the aim of developing recommendations on cretiera for hormone sensitivity and resistance in HER2-negative luminal MBC and facilitating clinical decision-making.

Methods

This consensus document was generated using a modification of the RAND/UCLA methodology, which included the definition of the project and identification of issues of interest, a non-exhaustive systematic review of the literature, an analysis and synthesis of the scientific evidence, preparation of recommendations, and external evaluation with a panel of 64 medical oncologists specializing in breast cancer.

Results

A Spanish panel of experts reached consensus on 32 of the 32 recommendations/conclusions presented in the first round and were accepted with an approval rate of 100% about definition of metastatic disease not susceptible to local curative treatment, definition of hormone sensitivity and hormone resistance in metastatic luminal disease and therapeutic decision-making.

Conclusion

We have developed a consensus document with recommendations on the treatment of patients with HER2-negative luminal MBC that will help to improve therapeutic benefits.