Advances in first-line treatment for patients with HER-2+ metastatic breast cancer

A Systematic Review of Health-Related Quality of Life in Women with HER2-Positive Metastatic Breast Cancer Treated with Trastuzumab

BACKGROUND

Many trials of human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer treatment with trastuzumab have provided evidence of improved clinical outcomes. This systematic review examined how a regimen that includes trastuzumab affects patients' health-related quality of life (HRQoL) during and after treatment.

METHODS

A systematic search for articles published up to February 2023 without restrictions of language or publication year was performed using the Pubmed, Embase, and Scopus databases. We included studies of women aged > 18 years with metastatic HER2-positive breast cancer treated with a trastuzumab-containing regimen. We assessed the quality of the studies using the Cochrane Risk of Bias (RoB) tool (2.0) for randomized controlled trials (RCTs) and the Risk Of Bias In Non-randomised Studies-of Interventions (ROBINS-I) tool for cross-sectional studies. We used Microsoft Excel to extract and synthesize data, and documented the review procedure following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

In total, eight studies compared 1104 trastuzumab-treated patients and 1003 non-trastuzumab-treated patients. Most studies were RCTs (n = 7) and one was a prospective observational study. All the included studies used the EORTC-QLQ-C30, EORTC-QLQ-BR23, FACT-B, or FACT-G questionnaires. During treatment, patients taking regimens that included trastuzumab showed clinical improvement in HRQoL, social functioning, and role functioning. After the treatment, patients' HRQoL profiles in the trastuzumab and chemotherapy arms were similar. However, trastuzumab (versus chemotherapy) treatment led to clinically improved functional status, role and physical functioning, and fatigue. The quality assessment revealed some concerns in most RCTs, with the risk of bias being high in two studies, low in one study, and moderate in the cross-sectional study.

CONCLUSIONS

Trastuzumab-containing regimens administered to HER2-positive breast cancer patients at the metastatic stage evidenced beneficial effects on total HRQoL during and after treatment. Upon therapy cessation, patients' HRQoL scores for both interventions improved. Nevertheless, HRQoL profiles of patients treated with trastuzumab were more favorable, particularly for functional status, role functioning, physical well-being, and fatigue.

CLINICAL TRIALS REGISTRATION

This review was registered in PROSPERO (registration number: CRD42021259826).

Human Epidermal Growth Factor Receptor 2 (HER2) Expression by Immunohistochemistry and Its Clinical Significance in Hepatocellular Carcinoma: A Single-Center Analysis

BACKGROUND

Human epidermal growth factor receptor 2 (HER2) is a member of the tyrosine kinase receptor family. It has been identified as an oncogene and is associated with poor outcomes in multiple tumor types. In hepatocellular carcinoma (HCC), there are contradictory data regarding the HER2 expression and its role in tumor development and progression. Some studies have identified HER2 expression as an early event during tumorigenesis, which decreases with progression and metastasis. Additional data provided evidence that treatment with anti-HER2 therapy resulted in local response and reduction in the metastasis rate in HCC mice models.

METHODS

Patients with histological diagnoses of HCC between 2010 and 2020 were included. HER2 staining was performed by immunohistochemistry (IHC), and scoring was done in accordance with the gastric cancer guidelines as 0, 1+, 2+, and 3+. Clinicopathological features were accessed by medical records. This study aims to evaluate HER2 expression by IHC in HCC and to correlate this expression with some clinicopathological features such as Barcelona Clinic Liver Cancer (BCLC) staging, number of hepatic lesions, alpha-fetoprotein level, underlying liver disease, presence of liver cirrhosis, Child-Pugh score, and tumor recurrence.

RESULTS

A total of 57 specimens from 54 patients were included. Of the patients, 85% were men, and the median age at diagnosis was 71 years (interquartile range: 59-75 years). Regarding stage, 61% were at stage 0-A of BCLC. Of the patients, 57% had a solitary HCC nodule. Concerning treatment, surgery was performed in 50% of the patients. HER2 expression was identified in seven patients: five in the membrane and two in the cytoplasm. Concerning the membrane staining, HER2 expression was scored as 1+/2+ in 7.4% (n = 4 patients). Of the patients with HER2 expression, four had a BCLC stage of 0-A and a single HCC nodule; alpha-fetoprotein was <400 ng/mL in all cases. There was no correlation to clinicopathological features. In one patient with HER2 2+ expression at diagnosis, this expression was not identified at tumor progression. Median disease-free survival in HER2 with IHC scores 1+/2+ and cytoplasmatic was 38 months versus 22 months in HER2 with a score of 0 (p = 0.604).

CONCLUSIONS

HER2 expression is a rare event in HCC. It was not possible to identify any relation to clinicopathological features. However, when we relate our data to previous trials, HER2 appears to be an early event in the course of HCC.

Molecular Assessment of HER2 to Identify Signatures Associated with Therapy Response in HER2-Positive Breast Cancer

Simple Summary

The HER2 status of breast cancers is accurately determined by measuring HER2 protein overexpression and gene amplification. However, these clinical diagnostic tests cannot predict the response to therapy. Single molecule imaging approaches can quantify molecular features of HER2, such as receptor nano-organization, with exquisite spatial resolution and sensitivity. The aim of our study was to assess how the molecular features of HER2 varied with the therapy response. According to our results in cultured cell lines and six patient specimens, the therapy response was associated with high detected HER2 densities and clustering. This advanced imaging approach can thus provide key data to complement the current diagnostic standards.

Abstract

Trastuzumab, the prototype HER2-directed therapy, has markedly improved survival for women with HER2-positive breast cancers. However, only 40–60% of women with HER2-positive breast cancers achieve a complete pathological response to chemotherapy combined with HER2-directed therapy. The current diagnostic assays have poor positive-predictive accuracy in identifying therapy-responsive breast cancers. Here, we deployed quantitative single molecule localization microscopy to assess the molecular features of HER2 in a therapy-responsive setting. Using fluorescently labeled trastuzumab as a probe, we first compared the molecular features of HER2 in trastuzumab-sensitive (BT-474 and SK-BR-3) and trastuzumab-resistant (BT-474^R and JIMT-1) cultured cell lines. Trastuzumab-sensitive cells had significantly higher detected HER2 densities and clustering. We then evaluated HER2 in pre-treatment core biopsies from women with breast cancer undergoing neoadjuvant therapy. A complete pathological response was associated with a high detected HER2 density and significant HER2 clustering. These results established the nano-organization of HER2 as a potential signature of therapy-responsive disease.

A framework for the use of biological medicines in the free state province, South Africa

PURPOSE

The use of biological medicines (BM) has increased worldwide owing to their effectiveness in the treatment of many chronic diseases. However, in South Africa, access to BM remains limited, hence, there is a need to develop strategies that will enable timely access to BM by all patients who need them.

OBJECTIVE

To develop a framework for the use of BM in South Africa.

METHODS

Using a Delphi questionnaire that was developed by integration of the opinions of newly qualified doctors (<2 years practice), prescribing specialists, and patients using BM, a Delphi method was used to guide an experts' panel into consensus on the different opinions in the questionnaire, and from this, a framework for the use of BM was constructed.

RESULTS

From the surveys, 76.2% of the newly qualified doctors and 91.7% of the prescribing specialists indicated that they had limited knowledge on the pharmacology of BM, and, respectively, 64.5% and 77.8% admitted that their knowledge on BM was not adequate for prescribing and taking care of patients on BM. Also, 58.3% and 75% of the prescribers indicated that the high cost and the tedious procurement process, respectively, were barriers of access to BM. The Delphi panel reached consensus after two rounds, and the resultant framework recommends that, appropriate use of BM requires establishing guidelines for the use of BM, increasing BM content in the medical training programs and information resources used by healthcare professionals, enacting drug regulations and drug policies that will increase availability of BM, offering appropriate patient information and public engagement.

CONCLUSION

The lack of knowledge on BM by health professionals, together with the high cost and a complex procurement processes are the major impediment to access to BM. A framework for the use of BM in South Africa was successfully developed to address these and other challenges.

Comparison of healthcare resource utilization and costs of patients with HR+/HER2- advanced breast cancer treated with ribociclib versus other CDK4/6 inhibitors

AIMS

To assess healthcare resource utilization (HRU) and healthcare costs among women with hormone receptor-positive and human epidermal growth factor receptor 2-negative advanced breast cancer (HR+/HER2- aBC) treated with cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors.

METHODS

Women with HR+/HER2- aBC, initiating CDK4/6 inhibitor treatment were identified using IBM MarketScan Commercial and Medicare Supplemental databases (Q1/2000-Q3/2018). Based on the first CDK4/6 inhibitor patients received (index therapy), three cohorts were identified: abemaciclib, palbociclib, and ribociclib. The baseline period (six months preceding treatment initiation) was used to describe patient characteristics. All-cause HRU and direct total healthcare costs (medical and pharmacy) from treatment initiation until the earliest of the end of index therapy, continuous health plan enrollment, or data availability, were compared for the ribociclib cohort versus the abemaciclib and palbociclib cohorts, separately, using weighted regression analyses balanced on baseline covariates.

RESULTS

Average age at treatment initiation was ∼60 years and the majority of patients were postmenopausal (abemaciclib: 92%; palbociclib: 92%; ribociclib: 79%). Average follow-up duration was 3.9, 8.8, and 5.9 months for the abemaciclib, palbociclib, and ribociclib cohorts, respectively. After reweighting, HRU was not statistically different between the ribociclib and abemaciclib cohorts, however, the ribociclib cohort incurred significantly lower total healthcare costs (-$5,452; 95% CI: -$8,726; -$1,139, p = .01). Medical costs (driven by outpatient costs) and pharmacy costs (driven by CDK4/6 inhibitor costs) were significantly lower for the ribociclib cohort. Among the reweighted ribociclib and palbociclib cohorts, HRU and total healthcare costs were not statistically different, although the ribociclib cohort had lower outpatient costs per-patient-per-month (-$1,245, 95% CI: -$2,349; -$37, p = .04).

LIMITATIONS

Due to the retrospective, observational design, treatment cohorts were not randomly assigned.

CONCLUSIONS

During CDK4/6 inhibitor therapy, ribociclib patients tended to incur lower medical and pharmacy costs than abemaciclib patients. Among ribociclib and palbociclib patients, HRU and healthcare costs were similar.

AllergoOncology: High innate IgE levels are decisive for the survival of cancer-bearing mice

Background

Atopics have a lower risk for malignancies, and IgE targeted to tumors is superior to IgG in fighting cancer. Whether IgE-mediated innate or adaptive immune surveillance can confer protection against tumors remains unclear.

Objective

We aimed to investigate the effects of active and passive immunotherapy to the tumor-associated antigen HER-2 in three murine models differing in Epsilon-B-cell-receptor expression affecting the levels of expressed IgE.

Methods

We compared the levels of several serum specific anti-HER-2 antibodies (IgE, IgG1, IgG2a, IgG2b, IgA) and the survival rates in low-IgE ΔM1M2 mice lacking the transmembrane/cytoplasmic domain of Epsilon-B-cell-receptors expressing reduced IgE levels, high-IgE KN1 mice expressing chimeric Epsilon-Gamma1-B-cell receptors with 4-6-fold elevated serum IgE levels, and wild type (WT) BALB/c. Prior engrafting mice with D2F2/E2 mammary tumors overexpressing HER-2, mice were vaccinated with HER-2 or vehicle control PBS using the Th2-adjuvant Al(OH)₃ (active immunotherapy), or treated with the murine anti-HER-2 IgG1 antibody 4D5 (passive immunotherapy).

Results

Overall, among the three strains of mice, HER-2 vaccination induced significantly higher levels of HER-2 specific IgE and IgG1 in high-IgE KN1, while low-IgE ΔM1M2 mice had higher IgG2a levels. HER-2 vaccination and passive immunotherapy prolonged the survival in tumor-grafted WT and low-IgE ΔM1M2 strains compared with treatment controls; active vaccination provided the highest benefit. Notably, untreated high-IgE KN1 mice displayed the longest survival of all strains, which could not be further extended by active or passive immunotherapy.

Conclusion

Active and passive immunotherapies prolong survival in wild type and low-IgE ΔM1M2 mice engrafted with mammary tumors. High-IgE KN1 mice have an innate survival benefit following tumor challenge.

Current Therapies for Human Epidermal Growth Factor Receptor 2-Positive Metastatic Breast Cancer Patients

The median survival of patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) has more than doubled, since the discovery of HER2-targeted treatments: it rose from less than 2 years in 2001 (prior introduction of trastuzumab) to more than 4 years in 2017. The initial generation of HER2-targeted therapies included trastuzumab with taxanes in the first line, followed by the addition of lapatinib and by a switch to another cytotoxic agent after progression. Results of CLEOPATRA, EMILIA, and TH3RESA trials have changed this clinical practice. The current consensus includes horizontal dual blockade (trastuzumab + pertuzumab) with taxanes or vinorelbine in the first line, followed by trastuzumab-emtansine (T-DM1) in the second line, with addition of lapatinib in the later lines of treatment. However, the fast and simultaneous development of new drugs led to a relative shortage of clinical evidence to support this sequence. Triple-positive breast cancers (TPBC), which express both hormonal receptors and HER2, constitute nearly half of HER2-positive cases. For these tumors, the current consensus is to add endocrine therapy after completion of cytotoxic treatment. Again, this consensus is not fully evidence-based. In view of the recent progress in treatment of estrogen-receptor positive breast cancers, a series of trials is evaluating addition of CDK4/6 inhibitors, aromatase inhibitors or fulvestrant to HER2-targeted and cytotoxic chemotherapy in TPBC patients. Despite the remarkable progress in treatment of HER2-positive breast cancer, metastatic disease is still incurable in the majority of patients. A wide range of novel therapies are under development to prevent and overcome resistance to current HER2-targeted agents. This review discusses pivotal clinical trials that have shaped current clinical practices, the current consensus recommendations, and the new experimental treatments in metastatic HER2-positive breast cancer.

Formation of multimeric antibodies for self-delivery of active monomers

Proteins and peptides have been used as drugs for almost a century. Technological advances in the past 30 years have enabled the production of pure, stable proteins in vast amounts. In contrast, administration of proteins based on their native active conformation (and thus necessitating the use of subcutaneous injections) has remained solely unchanged. The therapeutic anti-HER2 humanized monoclonal immunoglobulin (IgG) Trastuzumab (Herceptin) is a first line of the treatment for breast cancer. Chicken IgY is a commercially important polyclonal antibody (Ab). These Abs were examined for their ability to self-assemble and form ordered aggregates, by several biophysical methods. Atomic force microscopy analyses revealed the formation of multimeric nanostructures. The biological activity of multimeric IgG or IgY particles was retained and restored, in a dilution/time-dependent manner. IgG activity was confirmed by a binding assay using HER2 + human breast cancer cell line, SKBR3, while IgY activity was confirmed by ELISA assay using the VP2 antigen. Competition assay with native Herceptin antibodies demonstrated that the binding availability of the multimer formulation remained unaffected. Under long incubation periods, IgG multimers retained five times more activity than native IgG. In conclusion, the multimeric antibody formulations can serve as a storage depositories and sustained-release particles. These two important characteristics make this formulation promising for future novel administration protocols and altogether bring to light a different conceptual approach for the future use of therapeutic proteins as self-delivery entities rather than conjugated/encapsulated to other bio-compounds.

Efficacy and safety of trastuzumab combined with chemotherapy for first-line treatment and beyond progression of HER2-overexpressing advanced breast cancer

Objective

To observe the efficacy and safety of trastuzumab combined with chemotherapy in patients with human epidermal growth factor receptor 2 (HER2)-overexpressing advanced breast cancer.

Methods

A total of 90 patients with HER2-overexpressing advanced breast cancer were enrolled in this study. All patients were diagnosed with ductal invasive breast cancer by pathological analysis, and were aged between 31–73 years with a median of 51 years. HER2-positivity was defined as 3(+) staining in immunochemistry or amplification of fluorescence in situ hybridization (FISH, ratio ≥2.0). Trastuzumab was administered in combination with chemotherapy as first-line treatment and beyond progression as a secondline, third-line, and above treatment in 90, 34, 14, and 6 patients, respectively. The chemotherapy regimen was given according to normal clinical practice. The response rate was evaluated every two cycles, and the primary endpoints were progression-free survival (PFS) and overall survival (OS). Survival curves were estimated by using Kaplan-Meier graphs and were compared by using log-rank test statistics. Multivariate analysis was done using Cox’s proportional hazards regression model, and the level of significance was P<0.05.

Results

All 90 patients received at least one dose of trastuzumab, and efficacy could be evaluated in 85 patients. The median follow-up was 50 months. In total, 72 (80.00%) patients had visceral metastasis, and 43 (47.78%) patients had progressed after one or more extensive chemotherapy regimens for metastatic diseases. The median PFS for first-line trastuzumab was 10 months (range, 2–59 months), and the median OS after metastasis or initially local advanced disease was 22 months (range, 2–116 months).

Conclusions

Trastuzumab combined with chemotherapy was active and well-tolerated as a first-line treatment and even beyond progression in HER2-overexpressing advanced breast cancer as a second-line or third-line treatment. However, its efficacy is certainly less beyond this point.

Duration of trastuzumab in patients with HER2-positive metastatic breast cancer in prolonged remission

BACKGROUND

Outcomes in metastatic breast cancer (mbc) positive for her2 (human epidermal growth factor receptor 2) are generally unfavourable. Trastuzumab has revolutionized the prognosis of her2-positive mbc. Some her2-positive mbc patients go into prolonged remission, and a few patients remain in remission even after discontinuation of trastuzumab, suggesting the possibility of a cure. In our practice, 4 her2-positive mbc patients treated with chemotherapy and trastuzumab have remained in remission on maintenance therapy for 5 years or more. Of those 4 patients, 2 have continued in remission after discontinuation of trastuzumab for more than 1 year. The objective of the present paper was therefore to address the duration of trastuzumab therapy in her2-positive mbc patients in prolonged remission.

METHODS

We conducted a literature review of the duration of trastuzumab in her2-positive mbc patients in remission. We also conducted an online survey of oncologists in Ontario to determine their treatment practices in her2-positive mbc patients.

RESULTS

The literature search found no specific evidence about the optimal duration of trastuzumab maintenance therapy in her2-positive mbc in prolonged remission. However, retrospective studies suggest predictive markers of good prognosis in patients in complete remission taking maintenance trastuzumab. Identifying those markers could lead to more personalized treatment. Our survey of oncologists about their treatment practices in her2-positive mbc patients revealed that 82.93% of respondents (n = 34) follow the currently available guidelines.

CONCLUSIONS

With the emergence of patients in prolonged remission, duration of trastuzumab in her2-positive mbc has become an important and relevant clinical question worldwide. Collaborative efforts are needed for the further study of this topic.

Translating neoadjuvant therapy into survival benefits: one size does not fit all

Neoadjuvant therapy has been established as an effective therapeutic approach for patients with locally advanced breast cancer. Similar outcomes between neoadjuvant and adjuvant chemotherapy have been demonstrated in several trials. Nevertheless, neoadjuvant therapy has some advantages over adjuvant therapy, including tumour downstaging, in vivo assessment of therapeutic efficacy, reduced treatment durations, and the need to enrol fewer patients for clinical trials to reach their preplanned objectives. The number of neoadjuvant trials in patients with breast cancer has increased substantially in the past 5 years, particularly in the context of HER2-positive disease. Substantial improvements in the pathological complete response rate to anti-HER2 therapy, a proposed surrogate end point for long-term clinical benefit, have been observed with neoadjuvant dual-agent HER2 blockade. Thus, it was hypothesized that this approach would provide additional survival benefits over standard-of-care therapy with the anti-HER2 antibody trastuzumab in the adjuvant setting. Emerging data, however, are calling this notion into question. We discuss potential reasons why results of neoadjuvant trials of targeted therapies have not been mirrored in the adjuvant setting, and other than inherent differences in clinical-trial designs and statistical power, we consider how the biology of the disease, patient characteristics, and drug administration and schedule might influence the results.

Anti-HER2 Therapy Beyond Second-Line for HER2-Positive Metastatic Breast Cancer: A Short Review and Recommendations for Several Clinical Scenarios from a Spanish Expert Panel

BACKGROUND

The aim of this project was to provide an expert opinion regarding anti-human epidermal growth factor receptor 2 (HER2) therapy beyond second-line treatment of metastatic breast cancer (mBC).

METHODS

A group of experts discussed specific issues concerning anti-HER2 therapy in late-line settings in mBC.

RESULTS

Trastuzumab emtansine (T-DM1) or dual HER2 blockade appeared to be good options for HER2-positive mBC after ≥ 2 HER2-targeted therapies. Once an objective response has been achieved with anti-HER2-containing therapy, the anti-HER2 agent can be continued until progression of the disease, unacceptable toxicity or patient decision. mBC treated with ≥ 3 consecutive lines of anti-HER therapy, ≥ 1 being a dual HER2 blockade and with early progression of disease during a fourth or later-line treatment, are clinically resistant to anti-HER therapy. For progression of metastasis in the brain after anti-HER2 therapy, lapatinib and chemotherapy appear to be a good alternative after best local treatment.

CONCLUSIONS

Further clinical trials are needed to provide valuable knowledge about the best treatment options in the later settings of mBC.

Analysis of different HER-2 mutations in breast cancer progression and drug resistance

Studies over the last two decades have identified that amplified human epidermal growth factor receptor (HER‐2; c‐erbB‐2, neu) and its overexpression have been frequently implicated in the carcinogenesis and prognosis in a variety of solid tumours, especially breast cancer. Lots of painstaking efforts were invested on the HER‐2 targeted agents, and significantly improved outcome and prolonged the survival of patients. However, some patients classified as ‘HER‐2‐positive’ would be still resistant to the anti‐HER‐2 therapy. Various mechanisms of drug resistance have been illustrated and the alteration of HER‐2 was considered as a crucial mechanism. However, systematic researches in regard to the HER‐2 mutations and variants are still inadequate. Notably, the alterations of HER‐2 play an important role in drug resistance, but also have a potential association with the cancer risk. In this review, we summarize the possible mutations and focus on HER‐2 variants’ role in breast cancer tumourigenesis. Additionally, the alteration of HER‐2, as a potential mechanism of resistance to trastuzumab, is discussed here. We hope that HER‐2 related activating mutations could potentially offer more therapeutic opportunities to a broader range of patients than previously classified as HER‐2 overexpressed.

Impact of age-related socio-economic and clinical determinants of quality of life among long-term breast cancer survivors

OBJECTIVES

The main purpose of this study was to identify age-related socioeconomic and clinical determinants of quality of life among breast cancer survivors five years after the diagnosis. The secondary objective was to describe quality of life in the studied population according to age.

STUDY DESIGN

A cross-sectional survey in five-year breast cancer survivors was conducted in women diagnosed with breast cancer in 2007 and 2008 in Côte d'Or.

MAIN OUTCOME MEASURES

Quality of life was assessed with the SF-12, the EORTC-QLQ-C30 and the EORTC-QLQ-BR23 questionnaires. Socio-economic deprivation was assessed by the EPICES questionnaire. Social support was assessed by the Sarason questionnaire and clinical features were collected through the Côte d'Or breast cancer registry. Age-related determinants of quality of life were identified using multivariate mixed model analysis for each SF-12 dimension.

RESULTS

Overall 396 women completed the questionnaires. Women aged <65 years had a better quality of life and a greater availability of social support than did women aged ≥65 years. Body mass index, relapse and EPICES were found to be determinants of quality of life in younger women (p<0.006). For older women, comorbidities and EPICES deprivation scores were predictors of low quality of life scores (p<0.006).

CONCLUSIONS

Five years after breast cancer diagnosis, disease severity did not affect quality of life. The major determinants of quality of life in younger women were disease relapse and EPICES deprivation scores while those in older women were comorbidities and EPICES deprivation scores.

[Update of breast cancer in primary care (IV/V)]

Breast cancer is a prevalent disease affecting all areas of patients' lives. Therefore, family physicians must thoroughly understand this pathology in order to optimize the health care services and make the best use of available resources, for these patients. A series of 5 articles on breast cancer is presented below. It is based on a review of the scientific literature over the last 10 years. This fourth article deals with the treatment of the disease, the role of the primary care physician, and management of major complications. This summary report aims to provide a current and practical review about this problem, providing answers to family doctors and helping them to support their patients and care for them throughout their illness.

Neoadjuvant treatment of HER2 and hormone-receptor positive breast cancer - moving beyond pathological complete response

Pathologic complete response (pCR) was noted to be prognostic in all but hormone receptor-positive (HR) breast cancer cases even when HER2 is overexpressed. Evocative data suggest that HER2-positive breast cancer patients are a heterogeneous population and a subset of HER2-positive and HR-positive tumors biologically behave more like HER2-negative. Identification and targeted monitoring of these patients is crucial to consolidate data aiming to optimize combination treatment with new agents, thereby avoiding overtreatment with chemotherapy. The questions surrounding HER2-positive and HR-positive breast cancer patients treatment as well as the potential direction towards development of surrogate markers alternative to pCR are discussed.

Use of pertuzumab for the treatment of HER2-positive metastatic breast cancer

INTRODUCTION

Targeting the human epidermal growth factor receptor (HER) family of tyrosine kinase receptors has proven to be effective as a therapeutic strategy for HER type 2 (HER2)-positive breast cancer. Since resistance to trastuzumab occurs relatively frequently, particularly in the metastatic setting, novel anti-HER2 targeted therapies with complementary and/or synergistic mechanisms of action have been under development. Pertuzumab, a HER2-targeted monoclonal antibody that prevents HER2 dimerisation, is the first of a class of promising targeted agents for the treatment of HER2-positive breast cancer.

METHODS

A review of the biomedical literature published prior to February 2013 was conducted in English using PubMed. ClinicalTrials.gov was searched for appropriate clinical trials. The search terms used included breast neoplasm, pertuzumab, dimerisation, and HER2-positive. Abstracts of studies presented at the ASCO and ESMO Annual Meetings, and San Antonio Breast Cancer Symposium were also included.

RESULTS

Pertuzumab represents a novel anti-HER2 targeted therapy for HER2-positive breast cancers. In this article, we describe the mechanism of action of pertuzumab, as well as its drug development process and preclinical testing results. Based on the results of ancillary studies, dual inhibition using pertuzumab and trastuzumab was shown to be effective for the management of HER2-positive metastatic breast cancers pre-treated with trastuzumab-based therapy. For the first-line setting, the combination of both pertuzumab and trastuzumab with docetaxel (CLEOPATRA trial; clinical evaluation of pertuzumab and trastuzumab) has changed the paradigm of patient management.

CONCLUSION

Pertuzumab provided a more comprehensive inhibition of HER2-driven signalling pathways. When administered together with trastuzumab, pertuzumab represent a significant advancement for the treatment of HER2-positive metastatic breast cancer patients.

Circulating tumour cells and cell-free DNA as tools for managing breast cancer

Circulating blood biomarkers promise to become non-invasive real-time surrogates for tumour tissue-based biomarkers. Circulating biomarkers have been investigated as tools for breast cancer diagnosis, the dissection of breast cancer biology and its genetic and clinical heterogeneity, prognostication, prediction and monitoring of therapeutic response and resistance. Circulating tumour cells and cell-free plasma DNA have been analysed in retrospective studies, and the assessment of these biomarkers is being incorporated into clinical trials. As the scope of breast cancer intratumour genetic heterogeneity unravels, the development of robust and standardized methods for the assessment of circulating biomarkers will be essential for the realization of the potentials of personalized medicine. In this Review, we discuss the current status of blood-born biomarkers as surrogates for tissue-based biomarkers, and their burgeoning impact on the management of patients with breast cancer.

OSU-03012 sensitizes breast cancers to lapatinib-induced cell killing: a role for Nck1 but not Nck2

Background

Lapatinib is characterized as an ErbB1/ErbB2 dual inhibitor and has recently been approved for the treatment of metastatic breast cancer. In this study, we examined mechanisms associated with enhancing the activity of lapatinib via combination with other therapies.

Methods

In the present studies, estrogen receptor (ER) positive and ER negative breast cancer cells were genetically manipulated to up- or downregulate eIF2-alpha, its phospho-mutant, Nck1, or Nck2, then treated with OSU-03012, lapatinib or the combination and assayed for cytotoxicity/cytostaticity using clonogenic assays.

Results

Treatment of breast cancer cell lines with lapatinib and OSU-03012 (a small molecule derivative of the Cox-2 inhibitor celecoxib) induced synergistic cytotoxic/cytostatic effects. This combination therapy corresponded to an increase in the phosphorylation of eIF2-α at serine⁵¹ and a decrease in Nck1 expression. Ectopic expression of phospho-mutant eIF2-α (Ser⁵¹Ala) or downregulation of eIF2-α in addition to downregulation of the eIF2-α kinase PERK inhibited the synergistic and cytotoxic effects. Furthermore, ectopic expression of Nck1, but not Nck2 abolished the decrease in cell viability observed in combination-treated cells. Downregulation of Nck1 failed to “rescue” the ablation of the cytotoxic/cytostatic effects by the phospho-mutant of eIF2-α (Ser⁵¹Ala) demonstrating that Nck1 downregulation is upstream of eIF2-α phosphorylation in the anti-survival pathway activated by lapatinib and OSU-03012 treatment. Finally, co-immunoprecipitation assays indicated that eIF2-α dissociates from the Nck1/PP1 complex after OSU-03012 and lapatinib co-treatment.

Conclusions

These data indicate that OSU-03012 and lapatinib co-treatment is an effective combination therapy, which functions to enhance cell killing through the Nck1/eIF2 complex. Hence, this complex is a novel target for the treatment of metastatic breast cancer.

Targeted inhibition of Hsp90 by ganetespib is effective across a broad spectrum of breast cancer subtypes

Heat shock protein 90 (Hsp90) is a molecular chaperone essential for the stability and function of multiple cellular client proteins, a number of which have been implicated in the pathogenesis of breast cancer. Here we undertook a comprehensive evaluation of the activity of ganetespib, a selective Hsp90 inhibitor, in this malignancy. With low nanomolar potency, ganetespib reduced cell viability in a panel of hormone receptor-positive, HER2-overexpressing, triple-negative and inflammatory breast cancer cell lines in vitro. Ganetespib treatment induced a rapid and sustained destabilization of multiple client proteins and oncogenic signaling pathways and even brief exposure was sufficient to induce and maintain suppression of HER2 levels in cells driven by this receptor. Indeed, HER2-overexpressing BT-474 cells were comparatively more sensitive to ganetespib than the dual HER2/EGFR tyrosine kinase inhibitor lapatinib in three-dimensional culture. Ganetespib exposure caused pleiotropic effects in the inflammatory breast cancer line SUM149, including receptor tyrosine kinases, MAPK, AKT and mTOR signaling, transcription factors and proteins involved in cell cycle, stress and apoptotic regulation, as well as providing combinatorial benefit with lapatinib in these cells. This multimodal activity translated to potent antitumor efficacy in vivo, suppressing tumor growth in MCF-7 and MDA-MB-231 xenografts and inducing tumor regression in the BT-474 model. Thus, ganetespib potently inhibits Hsp90 leading to the degradation of multiple clinically-validated oncogenic client proteins in breast cancer cells, encompassing the broad spectrum of molecularly-defined subtypes. This preclinical activity profile suggests that ganetespib may offer considerable promise as a new therapeutic candidate for patients with advanced breast cancers.

Tumor necrosis factor α stimulates Her-2 cleavage by activated caspase-8

BACKGROUND/AIM

Her-2 over-expression has been correlated with a poor prognosis in patients with breast cancer. Now, we explored the effect of TNF-α treatment and/or NFĸB activation on Her-2 expression in MCF-7 breast adenocarcinoma cells.

METHODS

Stably transfected MCF-7 cell lines with pcDNA3.0, IĸBα MT, c-FLIP/control shRNA were established by FuGENE with the supplementation of G418 (500 µg /ml). Western blot and Real-time PCR were applied to assess the expression levels of protein and mRNA of target gene. In addition, caspase-8 activity was evaluated by the incubation with a caspase-8 fluorogenic substrate, Ac-IEPD-AMC using a spectrofluorometer.

RESULTS

It was uncovered that Her-2 was a new substrate for caspase-8 and that tumor necrosis factor α (TNF-α) stimulation resulted in a caspase-8-dependent Her-2 cleavage in MCF-7 breast adenocarcinoma cells defective for nuclear factor ĸB (NFĸB) activation. We demonstrated that the antiapoptotic transcription factor NFĸB counteracted this cleavage through the induction of caspase-8 inhibitor, c-FLIP.

CONCLUSION

we propose a novel mechanism in which NFĸB functions as a new antiapoptotic factor by counteracting TNF-α-triggered Her-2 cleavage.