Defining the optimal sequence for the systemic treatment of metastatic breast cancer

Current and emerging treatment approaches for hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer

In the past decade, significant progress was made in treating hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (mBC), but many clinical questions remain. Cyclin-dependent kinase 4/6 inhibitors are now widely used in combination with endocrine therapy (ET) as standard of care, having demonstrated significant progression-free survival versus ET, and also significant overall survival benefits in the metastatic setting. Inhibition of the PI3K/AKT/mTOR intracellular signaling pathway coupled with ET typically follows first-line therapies. Novel endocrine options including oral selective estrogen receptor down-regulators (SERDs) are in late phases of development, with elacestrant being the first oral SERD to be approved for ESR1-mutant mBC. However, endocrine-refractory disease is inevitable in most patients and represents an area of unmet need, with current recommended options offering poor efficacy, undesirable toxicity, and reduced quality of life. Breakthrough advances in the metastatic setting came via the development of antibody-drug conjugates, which have the advantage of delivering cytotoxic payloads to tumor cells with higher tumor selectivity. Trastuzumab deruxtecan offers a novel therapeutic option for patients with HR+/HER2-low mBC and sacituzumab govitecan is a novel therapeutic option for patients with HR+/HER2- mBC, including those with unmet treatment need in the later-line endocrine-refractory setting. Data gaps still exist regarding optimal sequencing of these novel agents; additional studies into mechanisms of resistance in the metastatic setting would provide further insights. Herein, we describe the current treatment options for HR+/HER2- mBC, including the latest practice-impacting data, and provide commentary on future directions.

Preferences for the sequencing of first-line systemic treatments in metastatic hormone receptor-positive, HER2-negative breast cancer

Introduction

Metastatic breast cancer (MBC) is a diverse disease. Therapeutic options include hormonal therapy, chemotherapy, and targeted therapies. The optimal treatment sequence for patients with hormone receptor-positive (HR-positive), HER2-negative metastatic breast cancer remains unknown.

Methods

This was a retrospective and prospective study. The data was collected from the medical records of patients in a tertiary healthcare center in Lebanon between the years 2016 and 2019, and patients were followed up for a 3-year duration. The main aim was to identify oncologists' preferences in the choice and sequence of treatment for newly diagnosed and/or recurrent cases of HR-positive, HER2-negative MBC.

Results

A total of 51 patients were included. 24 patients received chemotherapy, while 27 received endocrine therapy as first-line treatment after a diagnosis of MBC, with a median overall survival (OS) of 13 months and a median progression-free survival (PFS) of 12 months after first-line treatment with chemotherapy, compared to 27 months and 18 months with endocrine therapy. A higher percentage of patients have received chemotherapy in the first-line setting compared to the data reported in the literature, with the choice being multifactorial.

Conclusion

Factors to consider in MBC management include the choice of first-line treatment, the optimal sequence of treatment, and the combination of available treatment options.

Exploring Breast Cancer Systemic Drug Therapy Patterns in Real-World Data

PURPOSE

To explore medications and their administration patterns in real-world patients with breast cancer.

METHODS

A retrospective study was performed using TriNetX, a federated network of deidentified, Health Insurance Portability and Accountability Act-compliant data from 21 health care organizations across North America. Patients diagnosed with breast cancer between January 1, 2013, and May 31, 2022, were included. We investigated a rule-based and unsupervised learning algorithm to extract medications and their administration patterns. To group similar administration patterns, we used three features in k-means clustering: total number of administrations, median number of days between administrations, and standard deviation of the days between administrations. We explored the first three lines of therapy for patients classified into six groups on the basis of their stage at diagnosis (early as stages I-III v late as stage IV) and the sensitivity of the tumor's receptors to targeted therapies: hormone receptor-positive/human epidermal growth factor 2-negative (HR+/ERBB2-), ERBB2-positive (ERBB2+/HR±), or triple-negative (TN; HR-/ERBB2-). To add credence to the derived regimens, we compared them to the National Comprehensive Cancer Network (NCCN): Breast Cancer (version 2.2023) recommendations.

RESULTS

In early-stage HR+/ERBB2- and TN groups, the most common regimens were (1) cyclophosphamide and docetaxel, administered once every 3 weeks for three to six cycles and (2) cyclophosphamide and doxorubicin, administered once every 2 weeks for four cycles, followed by paclitaxel administered once every week for 12 cycles. In the early-stage ERBB2+/HR± group, most patients were administered carboplatin and docetaxel with or without pertuzumab and with trastuzumab (for six or more cycles). Medications most commonly administered in our data set (7,798 patients) agreed with recommendations from the NCCN in terms of medications (regimens), number of administrations (cycles), and days between administrations (cycle length).

CONCLUSION

Although there is a general agreement with the NCCN Guidelines, real-world medication data exhibit variability in the medications and their administration patterns.

A Review of Margetuximab-Based Therapies in Patients with HER2-Positive Metastatic Breast Cancer

Breast cancer (BC) is the most commonly diagnosed cancer globally, with high mortality rates. Targeted drug therapies have revolutionized cancer treatment. For example, treatment with human epidermal receptor 2 (HER2) antagonists has markedly improved the prognosis of patients with HER2-positive BC (HER2 + BC). However, HER2+ metastatic BC (MBC) remains prevalent owing to its resistance to conventional anti-HER2 drugs. Therefore, novel agents are needed to overcome the limitations of existing cancer treatments and to enhance the progression-free and overall survival rates. Progress has been made by optimizing the fragment crystallizable (Fc) domain of trastuzumab, an IgG1 monoclonal, chimeric anti-HER2 antibody, to develop margetuximab. The modified Fc domain of margetuximab enhances its binding affinity to CD16A and decreases its binding affinity to CD32B, thereby promoting its antitumor activity. This review summarizes studies on the efficacy of margetuximab, discusses its utility as an anti-HER2 monoclonal antibody drug for the treatment of HER2 + BC, and presents the latest advances in the treatment of BC. This review provides insights into the clinical implication of margetuximab in HER2 + MBC treatment.

MicroRNAs as therapeutic targets in breast cancer metastasis

Breast cancer is a complex disease with multiple risk factors involved in its pathogenesis. Among these factors, microRNAs are considered for playing a fundamental role in the development and progression of malignant breast tumors. In recent years, various studies have demonstrated that several microRNAs exhibit increased or decreased expression in metastatic breast cancer, acting as indicators of metastatic potential in body fluids and tissue samples. The identification of these microRNA expression patterns could prove instrumental for the development of novel therapeutic molecules that either mimic or inhibit microRNA action. Additionally, an efficient delivery system mediated by viral vectors, nonviral carriers, or scaffold biomaterials is a prerequisite for implementing microRNA-based therapies; therefore, this review attempts to highlight essential microRNA molecules involved in the metastatic process of breast cancer and discuss recent advances in microRNA-based therapeutic approaches with potential future applications to the treatment sequence of breast cancer.

Exploring metastatic breast cancer treatment changes during COVID-19 pandemic

The emergency caused by COVID-19 pandemic has imposed a sudden reorganization of the healthcare structures and has created consequences in cancer patients management. General clinical recommendations for cancer patients were released, even if limited clinical cancer-specific data were available. A number of critical issues have come out during COVID-19 pandemic in the management of patients with metastatic breast cancer (MBC). To explore the changes in the treatment of patients with MBC during COVID-19 pandemic, we promoted a survey to the oncologists operating in the Italian breast units. The results of this survey show that Italian oncologists have tried to ensure continuity of care for patients with MBC. De-escalation of cancer treatments, especially monotherapy administration, and greater use of oral anticancer drugs are the main changes that emerge from this survey. Some subgroups of patients, especially the elderly and endocrine-responsive patients, have been undertreated during the COVID-19 pandemic.

Cellular Mechanisms Triggered by the Cotreatment of Resveratrol and Doxorubicin in Breast Cancer: A Translational In Vitro-In Silico Model

Doxorubicin (Doxo) is the most effective chemotherapeutic agent for the treatment of breast cancer. However, resistance to Doxo is common. Adjuvant compounds capable of modulating mechanisms involved in Doxo resistance may potentiate the effectiveness of the drug. Resveratrol (Rsv) has been tested as an adjuvant in mammary malignancies. However, the cellular and molecular mechanisms underlying the effects of cotreatment with Doxo and Rsv in breast cancer are poorly understood. Here, we combined in vitro and in silico analysis to characterize these mechanisms. In vitro, we employed a clinically relevant experimental design consisting of acute (24 h) treatment followed by 15 days of analysis. Acute Rsv potentiated the long-lasting effect of Doxo through the induction of apoptosis and senescence. Cells that survived to the cotreatment triggered high levels of autophagy. Autophagy inhibition during its peak of activation but not concomitant with Doxo+Rsv increased the long-term toxicity of the cotreatment. To uncover key proteins potentially associated with in vitro effects, an in silico multistep strategy was implemented. Chemical-protein networks were predicted based on constitutive gene expression of MCF7 cells and interatomic data from breast cancer. Topological analysis, KM survival analysis, and a quantitative model based on the connectivity between apoptosis, senescence, and autophagy were performed. We found seven putative genes predicted to be modulated by Rsv in the context of Doxo treatment: CCND1, CDH1, ESR1, HSP90AA1, MAPK3, PTPN11, and RPS6KB1. Six out of these seven genes have been experimentally proven to be modulated by Rsv in cancer cells, with 4 of the 6 genes in MCF7 cells. In conclusion, acute Rsv potentiated the long-term toxicity of Doxo in breast cancer potentially through the modulation of genes and mechanisms involved in Doxo resistance. Rational autophagy inhibition potentiated the effects of Rsv+Doxo, a strategy that should be further tested in animal models.

Significance of Targeting VEGFR-2 and Cyclin D1 in Luminal-A Breast Cancer

The hormonal luminal-A is the most pre-dominant sub type of breast cancer (BC), and it is associated with a high level of cyclin D1 in Saudi patients. Tamoxifen is the golden therapy for hormonal BC, but resistance of cancer cells to tamoxifen contributes to the recurrence of BC due to many reasons, including high levels of AIB1 and cyclin D1. Overcoming drug resistance could be achieved by exploring alternative targetable therapeutic pathways and new drugs or combinations. The objective of this study was to determine the differentially enriched pathways in 12 samples of Saudi women diagnosed with luminal-A using the PamChip peptide microarray-based kinase activity profiling, and to compare the activity of HAA₂₀₂₀ and dinaciclib with tamoxifen in singles and combinations in the MCF7 luminal-A cell line. Our results of network and pathway analysis of the 12 samples highlighted the importance of VEGFR and CDKs in promoting luminal-A breast cancer. The activation of VEGF signaling via VEGFR-2 leads to activation of PI3K/AKT kinases and an increase of cell survival, and leads to activation of Hsp90, which induces the phosphorylation of FAK1, resulting in cytoskeleton remodeling. PLC-gamma 1 is also activated, leading to FAK-2 and PKC activation. Notably, the G₁/S cell cycle phases and phosphorylation processes contribute to the top seven tumorigenesis processes in the 12 samples. Further, the MTT combination of HAA₂₀₂₀ and dinaciclib showed the best combination index (CI), was more clonogenic against MCF7 cells compared to the other combinations, and it also showed the best selectivity index (SI) in normal MRC5 cells. Interestingly, HAA₂₀₂₀ and dinaciclib showed a synergistic apoptotic and G₁ cell cycle effect in MCF7 cells, which was supported by their synergistic CDK2, cyclin D1, and PCNA inhibition activities. Additionally, the combination showed VEGFR-2 and Hsp90 inhibition activities in MCF7 cells. The results show the significance of targeting VEGFR-2 and cyclin D1 in Saudi luminal-A breast cancer patients, and the effect of combining HAA₂₀₂₀ and dinaciclib on those targets in the MCF7 model. It also warrants further preclinical and in vivo investigations for the combination of HAA₂₀₂₀ and dinaciclib as a possible future second-line treatment for luminal-A breast cancers.

Physician treatment of metastatic triple-negative breast cancer in the immuno-oncology era: a discrete choice experiment

Aim: Guidelines list atezolizumab with nab-paclitaxel (ANP) as the preferred first-line (1L) therapy for metastatic triple-negative breast cancer (mTNBC) with PD-L1 expression ≥1%, but which clinical attributes impact ANP prescribing? Materials & methods: Medical oncologists participated in a discrete choice experiment (DCE) with four hypothetical mTNBC clinical scenarios to assess influences of: PD-L1 expression, menopausal status, prior adjuvant therapy and bulky liver metastases. Results: A total of 47% chose ANP in 1L irrespective of menopausal status, prior adjuvant therapy or tumor bulk. PD-L1 expression was the only attribute with a significant impact on ANP preference, with 69% choosing ANP for those with ≥1% expression versus only 26% for those with <1% (p < 0.00001). Conclusion: ANP choice for 1L mTNBC deviated from guidelines.

Development and proof-of-concept of a multicenter, patient-centered cancer registry for breast cancer patients with metastatic disease-the "Breast cancer care for patients with metastatic disease" (BRE-4-MED) registry

Background

Patients with metastatic breast cancer (MBC) are treated with a palliative approach with focus on controlling for disease symptoms and maintaining high quality of life. Information on individual needs of patients and their relatives as well as on treatment patterns in clinical routine care for this specific patient group are lacking or are not routinely documented in established Cancer Registries. Thus, we developed a registry concept specifically adapted for these incurable patients comprising primary and secondary data as well as mobile-health (m-health) data.

Methods

The concept for patient-centered “Breast cancer care for patients with metastatic disease” (BRE-4-MED) registry was developed and piloted exemplarily in the region of Main-Franconia, a mainly rural region in Germany comprising about 1.3 M inhabitants. The registry concept includes data on diagnosis, therapy, progression, patient-reported outcome measures (PROMs), and needs of family members from several sources of information including routine data from established Cancer Registries in different federal states, treating physicians in hospital as well as in outpatient settings, patients with metastatic breast cancer and their family members. Linkage with routine cancer registry data was performed to collect secondary data on diagnosis, therapy, and progression. Paper and online-based questionnaires were used to assess PROMs. A dedicated mobile application software (APP) was developed to monitor needs, progression, and therapy change of individual patients. Patient’s acceptance and feasibility of data collection in clinical routine was assessed within a proof-of-concept study.

Results

The concept for the BRE-4-MED registry was developed and piloted between September 2017 and May 2018. In total n = 31 patients were included in the pilot study, n = 22 patients were followed up after 1 month. Record linkage with the Cancer Registries of Bavaria and Baden-Württemberg demonstrated to be feasible. The voluntary APP/online questionnaire was used by n = 7 participants. The feasibility of the registry concept in clinical routine was positively evaluated by the participating hospitals.

Conclusion

The concept of the BRE-4-MED registry provides evidence that combinatorial evaluation of PROMs, needs of family members, and raising clinical parameters from primary and secondary data sources as well as m-health applications are feasible and accepted in an incurable cancer collective.

Litchi Seed Aqueous Extracts play a role in suppression of epithelial-mesenchymal transition, invasion and migration in breast cancer cells

We carried out this study to unravel the function of Litchi Seed Aqueous Extracts (LSAE) on biological functions of breast cancer (BC) cells. MTT assay was adopted to measure proliferation of BC cells (MCF7, BT474 and MDA-MB-231) and normal mammary cells (MCF10A) under different time points (24, 48 and 72 h) and different concentrations (50, 100, 200 and 400 μg/mL). MCF-7 cells were selected for subsequent experiments and were grouped into blank group, negative control (NC) group, low-, medium- and high-dose LSAE (L-LSAE, M-LSAE, H-LSAE) groups. Cell viability, invasion, migration and apoptosis were measured by functional assays. Low dosage of LSAE (50 and 100 μg/mL) enhanced proliferation of MCF10A cells, while high dosage of LSAE (200 and 400 μg/mL) suppressed proliferation of MCF10A cells. The proliferation inhibition rate in BT474 and MDA-MB-231cells was increased relative to that in MCF7 cells. MCF-7 cells in the L-LSAE, M-LSAE and H-LSAE groups were rounded and epithelial-like, in which cell survival rate, epithelial-mesenchymal transition (EMT), invasion and migration abilities were reduced versus the blank and NC groups. The tendency in the H-LSAE group was substantially obvious than those in the L-LSAE and M-LSAE groups (both P < 0.05). We found that LSAE is able to inhibit EMT, invasion and migration in BC cells based on concentration and time.

Effect of pyruvate kinase M2-regulating aerobic glycolysis on chemotherapy resistance of estrogen receptor-positive breast cancer

This study aims to explore the effect and mechanism of pyruvate kinase M2 (PKM2) on chemotherapy resistance of estrogen receptor-positive breast cancer (ER BC) by regulating aerobic glycolysis. The expression of PKM2 in ER BC MCF-7 cells, T47D cells and MCF-7/ADR cells (which are subject to adriamycin/ADR induction) were determined by quantitative real-time PCR and western blot. MCF-7/ADR (M/A) cells were grouped into blank group (M/A), negative group (M/A+NC), low expression of PKM2 group (M/A+si-PKM2 group), overexpression of PKM2 group (M/A+PKM2 group) and glycolysis inhibition group (M/A+PKM2+2-DG group). Quantitative real-time PCR and western blot were applied to measure the expressions of PKM2, multidrug resistance, and glutathione-S-transferase π. Glucose and lactic acid kit was used to detect the amount of glucose uptake and lactic production. Cell variability, clone formation ability, and cell apoptosis were respectively measured by MTT, clone formation assay, and flow cytometry. Transwell assay and scratch assay were applied for cell invasion and migration ability. By overexpressing PKM2 in MCF-7 and T47D cells and using 2-DG, the effect on sensitivity of adriamycin amycin was explored. MCF-7/ADR cells have both elevated mRNA and protein expressions of PKM2 when compared with MCF-7 cells (both P<0.05). The cell activity of the M/A+si-PKM2+ADR group was notably lower than that in the M/A+ADR group and M/A+NC+ADR group (both P<0.05). In the M/A+si-PKM2 group, expressions of PKM2, multidrug resistance, and glutathione-S-transferase π, along with the amount of glucose uptake and lactic production, as well as cell variability, clone formation ability, and cell invasion and migration ability were inhibited, whereas cell apoptosis was increased in comparison with the M/A group and M/A+NC group (all P<0.05). On comparing with both the M/A group and the M/A+NC group, the M/A+si-PKM2 group displayed contrary tendency with the M/A+PKM2 group. The M/A+PKM2+2-DG group had elevated PKM2 expression compared with the M/A group and the M/A+NC group (all P<0.05). In MCF-7 and T47D cells with overexpression of PKM2, the sensitivity to adriamycin amycin, and cell apoptosis were suppressed, whereas the clone formation, invasion, and migration ability were enhanced. After 2-DG, the sensitivity on MCF-7 and T47D cells was enhanced while clone formation, invasion, migration and cell apoptosis rate were decreased (all P<0.05). PKM2 enhances chemotherapy resistance on ER BC by promoting aerobic glycolysis.

Broad consensus on the optimal sequence for the systemic treatment of metastatic breast cancer: results from a survey of Spanish medical oncologists

Objective: The aim of this survey conducted by 20 leading Spanish oncologists was to analyze the concurrence between Spanish clinical practice and the recently published definition of the optimal sequence for the systemic treatment of metastatic breast cancer (MBC) according to patient profiles.

Methods: A self-administered questionnaire was developed, divided into five sections comprising 34 specific questions related to sequential treatments, plus three additional general questions. Respondents were asked to justify negative answers. Participants were recruited randomly by invitation out of a total of 619 oncologists. The questionnaire was sent and collected via e-mail between October 2015 and May 2016. A total of 191 completed questionnaires were received.

Results: Overall, 70% of oncologists would keep the three patient profiles exactly as proposed (hormone receptor-positive and HER2-negative, HER2-positive, and triple negative breast cancer). Affirmative answers to questions regarding treatment sequences for these patient profiles (1–34) ranged from 77.8–99.5%, with an average of 90.9% of oncologists being in agreement with the recommended sequential treatments. The lowest degree of consensus was observed for endocrine treatments in pre-menopausal women and for chemotherapy options in hormone-resistant patients, whilst the highest degree of consensus was reached for targeted therapies in HER2-positive patients and for endocrine therapy in post-menopausal women. In their comments, participants revealed a number of economic constraints that prevented them from implementing some of the best treatment options.

Conclusions: In conclusion, despite the complexity of MBC treatment, there is general agreement on the optimal treatment sequences.

M-bioscore: proposing a new statistical model for prognostic factors in metastatic breast cancer patients

AIM

The current study aims to propose and internally validate 'M-bioscore', which is a model to help predict the outcomes of untreated metastatic breast cancer patients.

METHODOLOGY

Surveillance, epidemiology and end results (SEER) database (2010-2013) was accessed. Patients were divided into two groups: a training set and a validation set. Through a Cox proportional model, multivariate analysis for potential prognostic factors was performed. M-bioscore was calculated for all patients. Survival analyses were conducted through Kaplan-Meier analysis/log-rank testing.

RESULTS

A total of 6655 metastatic breast cancer patients were analyzed. In the training set, the following factors were linked to better cancer-specific survival in multivariate analysis: estrogen receptor positivity, isolated distant nodal metastases, progesterone receptor positivity, lower nuclear grade and HER2 neu positivity (p < 0.01). Cancer-specific survival was then assessed according to M-bioscore. Adjusted Cox regression cause-specific hazard (using breast cancer death as the event of interest) was evaluated in the validation cohort. Pairwise hazard ratio comparisons between different scores were significant (p < 0.05) except for the comparison between score 6 and 7. C-index for the validation cohort was 0.665 (Standard error (SE): 0.010; 95% CI: 0.646- 0.685).

CONCLUSION

M-bioscore can predict the outcomes of untreated metastatic breast cancer patients. Validation of external datasets is needed.

Current Landscape of Targeted Therapies for Hormone-Receptor Positive, HER2 Negative Metastatic Breast Cancer

The majority of deaths from MBC are in patients with hormone receptor (HR) positive, HER2 negative disease. Endocrine therapy (ET) remains the backbone of treatment in these cases, improving survival and quality of life. However, treatment can lose effectiveness due to primary or acquired endocrine resistance. Analysis of mechanisms of ET resistance has led to the development of a new generation of targeted therapies for advanced breast cancer. In addition to anti-estrogen therapy with selective estrogen receptor modulators, aromatase inhibitors, and/or selective estrogen receptor degraders, combinations with cyclin dependent kinase (CDK) 4/6 inhibitors have led to substantial progression free survival (PFS) improvements in the first and second line settings. While the PI3K/AKT/mTOR pathway is known to be an important growth pathway in HR positive breast cancer, PI3K inhibitors have been disappointing due to modest effect sizes and significant toxicity. The mTOR inhibitor everolimus significantly improves progression free survival when added to ET, and recent studies have improved supportive care allowing less toxicity. While these combination targeted therapies improve outcomes and often delay initiation of chemotherapy, long term overall survival data are lacking and data for the ideal strategy for sequencing these agents remains unclear. Ongoing research evaluating potential biomarkers and mechanisms of resistance is anticipated to continue to improve outcomes for patients with HR positive metastatic breast cancer. In this review, we will discuss management and ongoing challenges in the treatment of advanced HR positive, HER2 negative breast cancer, highlighting single agent and combination endocrine therapies, targeted therapies including palbociclib, ribociclib, abemaciclib, and everolimus, and sequencing of therapies in the clinic.

The economic burden of metastatic breast cancer in Spain

Objectives

The study aimed to estimate the burden of metastatic breast cancer (mBC) in Spain over 5 years.

Methods

An incidence-based cost-of-illness model was developed in which a cohort of patients with mBC was followed from the diagnosis of metastatic disease over 5 years or death. Resource use data were collected through a physician survey conducted with 10 clinical experts in Spain. The model distinguished patients according to HER2 and hormonal receptor (HR) status, and followed the patient cohort in monthly cycles.

Results

The incident cohort was estimated to be 2,923 patients with mBC, consisting of 1,575 HER2-/HR+, 520 HER2+/HR+, 324 HER2+/HR-, and 503 triple negative patients. The estimated mean survival over the 5-year time period was 2.51 years, on average, with longer survival of 3.36 years for HER2+/HR+, 2.41 years for HER2-/HR+, 2.82 years for HER2+/HR- and shortest mean survival of 1.74 years for triple negative patients. The total costs were €469,92,731 for the overall population, €190,079,787 for the HER2-/HR+, €151,045,260 for the HER2+/HR+, €80,827,171 for the HER2+/HR- and €47,540,512 for the triple negative subgroups over 5 years. Per patient total costs were €160,642 on average, €120,664 for HER2-/HR+, €290,346 for HER2+/HR+, €249,152 for HER2+/HR-and €94,572 for triple negative patients over 5 years.

Conclusions

The economic burden of mBC in Spain is significant, but differs by HER2 and HR status. HER2-/HR +patients account for the highest burden due to the prevalence of this category, but HER2+/HR +patients have the highest per patient costs.

Use of dual mTOR inhibitor MLN0128 against everolimus-resistant breast cancer

PURPOSE

HR+/HER2- aromatase inhibitor-resistant metastatic breast cancer can be treated with everolimus and a second AI until the cancer recurs. Targeting these everolimus-resistant patients with the latest standard of care, CDK4/6 inhibitors, has not been clearly addressed. Understanding the signaling transduction pathways, which everolimus resistance activates, will elucidate the mechanisms and offer treatment strategies of everolimus resistance.

METHODS

To mimic the clinical setting, letrozole-resistant cells were used to generate an everolimus-resistant model (RAD-R). Reverse phase protein array (RPPA) was performed to reveal changes in the signaling transduction pathways, and expression levels of key proteins were analyzed. Inhibitors targeting the major signaling pathways, a CDK4/6 inhibitor palbociclib and a mTORC1/2 inhibitor (MLN0128), were evaluated to establish resistance mechanisms of RAD-R.

RESULTS

RPPA results from RAD-R indicated changes to significant regulatory pathways and upregulation of p-AKT expression level associating with everolimus resistance. MLN0128, that inhibits the AKT phosphorylation, effectively suppressed the proliferation of RAD-R cells while treatment with palbociclib had no effect.

CONCLUSION

Among the many signaling transduction pathways, which are altered post everolimus resistance, targeting dual mTORC1/2 is a possible option for patients who have recurrent disease from previous everolimus treatment.

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.

First-line paclitaxel and cisplatin used sequentially or in combination in metastatic breast cancer: A phase II randomized study

INTRODUCTION

Breast cancer (BC) is the commonest cancer among females worldwide. Some patients present initially at advanced stages and more than 50% of them will develop metastasis (MBC) at some point. Compared to single agents, combination chemotherapy produces higher response rates (RR), longer progression-free survival (PFS) than single agents. This is associated with remarkably higher toxicities. At the same time, overall survival (OS) is comparable. This study aimed to compare safety and efficacy of combination and sequential chemotherapy.

PATIENTS AND METHODS

Forty-six MBC patients were randomized to receive 6 cycles of the combination of paclitaxel (175 mg/m²) and cisplatin (70 mg/m²) (combination PC) or paclitaxel for 3 cycles followed by cisplatin for 3 cycles (sequential PC). Endpoints were RR, PFS, OS and safety.

RESULTS

Both combination and sequential PC produced similar RR (52% in both arms) and disease control rates (78.3% vs. 73.9%, p = .652). Responses were faster in the combination arm. Median PFS was 8.2 months in the combination compared to 5.0 months in the sequential arm (p = .064). The median OS was 16.5 and 18.8 months in the combination and sequential arms, respectively (p = .866). The combination was more toxic than sequential PC. Grade 3 toxicities were higher with combination PC than to sequential PC (48% vs. 4.3%; p < .001).

CONCLUSION

Sequential agent chemotherapy may provide similar response rate and overall survival to combination chemotherapy with much lower toxicities. The former can be considered the standard practice in most instances.

Factors involved in cancer metastasis: a better understanding to "seed and soil" hypothesis

Metastasis has intrigued researchers for more than 100 years. Despite the development of technologies and therapeutic strategies, metastasis is still the major cause of cancer-related death until today. The famous "seed and soil" hypothesis is widely cited and accepted, and it still provides significant instructions in cancer research until today. To our knowledge, there are few reviews that comprehensively and correlatively focus on both the seed and soil factors involved in cancer metastasis; moreover, despite the fact that increasingly underlying mechanisms and concepts have been defined recently, previous perspectives are appealing but may be limited. Hence, we reviewed factors involved in cancer metastasis, including both seed and soil factors. By integrating new concepts with the classic hypothesis, we aim to provide a comprehensive understanding of the "seed and soil" hypothesis and to conceptualize the framework for understanding factors involved in cancer metastasis. Based on a dynamic overview of this field, we also discuss potential implications for future research and clinical therapeutic strategies.

Long-term management of patients with hormone receptor-positive metastatic breast cancer: Concepts for sequential and combination endocrine-based therapies

Treatment options for hormone receptor-positive (HR-positive) metastatic breast cancer (MBC) continue to increase in parallel with expanding knowledge about the complex biology of breast cancer subtypes and resistance mechanisms to endocrine therapy. For patients with HR-positive MBC, there are now an unprecedented number of endocrine-based treatment options that can improve long-term outcomes, while preserving or optimizing quality of life, and that can be used before selecting more cytotoxic chemotherapeutic regimens. In addition to antiestrogens, steroidal and nonsteroidal aromatase inhibitors, the selective estrogen-receptor degrader, fulvestrant, and new endocrine-based combinations provide significant and clinically meaningful improvements in outcomes in the first line setting and beyond. Also, new clinical scenarios and indications for monotherapy endocrine and targeted therapies continue to be explored. Patients have several therapeutic options when their disease progresses or becomes resistant, although the optimal sequencing of these therapies remains unclear. Ongoing research in the resistant/refractory setting is anticipated to continue improving the outlook for these patients. This review will discuss current and investigational approaches to sequential single-agent endocrine and endocrine-based combination therapy for the long-term management of patients with HR-positive, human epidermal growth factor receptor 2-negative MBC.