Systemic therapy for patients with advanced human epidermal growth factor receptor 2-positive breast cancer: American Society of Clinical Oncology clinical practice guideline

Clinical efficacy and safety of T-DM1 for patients with HER2-positive breast cancer

Purpose

The aim of this study was to evaluate the therapeutic efficacy and safety of trastuzumab emtansine (T-DM1) for the treatment of patients with human epidermal growth factor receptor 2-positive breast cancer.

Methods

We performed a systemic review and meta-analysis of the relevant published clinical studies. A computerized search was performed for controlled clinical trials of T-DM1 in targeted treatment. Overall survival, progression-free survival, objective response rate, symptom progression free, and adverse events (AEs) were evaluated.

Results

Eight eligible trials with a total of 2,016 patients with breast cancer were included in the present meta-analysis. The treatment of patients with breast cancer with T-DM1 was associated with significantly increased overall and progression-free survival when compared with controls (P<0.0001). An analysis of the objective response rate and symptom progression free also demonstrated favorable results for T-DM1 treatment (P≤0.0001). There was no significant difference between the T-DM1 and control groups with respect to nonhematologic or hematologic AEs (P=0.99 and P=0.30, respectively).

Conclusion

Overall, T-DM1 is efficacious in the treatment of patients with human epidermal growth factor receptor 2-positive breast cancer and low rates of AEs compared with controls.

Reinvention of chemotherapy: drug conjugates and nanoparticles

PURPOSE OF REVIEW

Recent advances in nanotechnology have addressed some of the issues related to lack of selectivity and nonspecific toxicities associated with conventional chemotherapy. Nanoparticles are therapeutic carriers that can be fine tuned for specific application and for passive or active tumor targeting.

RECENT FINDINGS

Although the nanoparticle field is rapidly expanding, there are to date only six nanoparticle-based drug delivery platforms and two antibody-drug conjugates that are clinically approved for cancer therapy. Here, we review the clinical data of liposomal anthracyclines, nanoparticle formulations of paclitaxel and trastuzumab emtansine. We then briefly comment on efficacy and safety issues of nanoparticles, as well as on the next-generation nanoparticles for cancer therapy.

SUMMARY

The emerging development of cancer nanotechnology offers the opportunity of reinvestigating the potential of cytotoxic agents, improving tumor targeting and drug delivery, leading to better safety profile and antitumor activity. Adding specificity to nanoparticles may allow personalization of cancer therapy using chemotherapy.

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.

Second-line single-agent chemotherapy in human epidermal growth factor receptor 2-negative metastatic breast cancer: A systematic review

BACKGROUND

No 'gold standard' exists for single-agent chemotherapy of human epidermal growth factor receptor 2-negative (HER2-negative) metastatic breast cancer (MBC) in the second-line. The objective of this systematic review is to identify and appraise overall survival (OS), progression-free survival (PFS), time to progression (TTP) and Grade ≥3 adverse event evidence for single-agent chemotherapy in this setting.

METHODS

MEDLINE, Embase and the Cochrane Library were searched to October 2013, and PubMed October 2013 to November 2014. Electronic database searches were supplemented with hand searching of reference lists and conferences. Eligible randomised controlled trials (RCTs) employed at least one single-agent chemotherapy treatment, enrolled HER2-negative or unselected MBC patients who had progressed following first-line chemotherapy within the metastatic setting, and reported outcomes of interest for the second-line setting.

RESULTS

Fifty-three RCTs were included in total, with most containing mixed populations by HER2 status and treatment line. Fourteen studies reported data specifically for second- and later-line treatment within the metastatic setting. Median overall survival (OS) in most trials was 8-13 months. Only one trial reported a significant difference between studied interventions in the second-line metastatic setting: nab-paclitaxel (n=131) conferred a statistically significant OS advantage vs. three-weekly paclitaxel (n=136) (median OS 13.0 vs. 10.7 months, respectively; hazard ratio 0.73, p=0.024) and improved overall safety.

CONCLUSION

One RCT demonstrated significant benefit in this setting in confirmed HER2-negative MBC alongside favourable safety. Treatment line terminology was imprecise. To reliably inform patient treatment decisions, quality-of-life data are needed and precise OS estimation according to underlying patient characteristics.

A Retrospective Study on the Efficacy of Trastuzumab in HER2-Positive and Tamoxifen-Refractory Breast Cancer with Brain Metastasis

BACKGROUND AND OBJECTIVE

The role of trastuzumab in breast cancer with brain metastasis is still in discussion. This study was conducted to investigate the efficacy of trastuzumab in the management of human epidermal growth factor receptor 2 (HER2)-positive, tamoxifen-refractory breast cancer with brain metastasis.

METHODS

This retrospective study was conducted between January 2008 and December 2012. A total of 33 patients receiving trastuzumab treatment for HER2-positive, tamoxifen-refractory breast cancer with brain metastasis were assigned to the experimental group, while a matched group of 35 patients who received systemic therapy without trastuzumab were assigned to the control group. Data on the patient characteristics and clinical outcomes were collected and evaluated.

RESULTS

Patients in the trastuzumab group showed a significantly better response to treatment than those in the control group (p = 0.025). Univariate and multivariate Cox proportional regression analyses indicated that progression-free survival was significantly longer in patients receiving trastuzumab therapy than in the control group (hazard ratio [HR] 2.213 [p = 0.003] and HR 3.056 [p < 0.001], respectively) and significantly shorter in patients with two or more extracranial metastases (HR 0.417 [p = 0.002] and HR 0.317 [p < 0.001], respectively). Furthermore, patients on trastuzumab treatment experienced longer overall survival than patients in the control group (HR 2.844 [p < 0.001] and HR 4.017 [p < 0.001], respectively), while shorter overall survival was seen in patients with two or more extracranial metastases (HR 0.524 [p = 0.021] and HR 0.430 [p = 0.005], respectively) and in those receiving capecitabine-based therapy as compared with anthracycline-based therapy (HR 0.558 [p = 0.030] and HR 0.449 [p = 0.011], respectively).

CONCLUSION

Trastuzumab was found to benefit patients with HER2-positive, tamoxifen-refractory breast cancer with brain metastasis by improving progression-free and overall survival.

Patterns of Chromosomal Aberrations in Solid Tumors

Chromosomal abnormalities are a defining feature of solid tumors. Such cytogenetic alterations are mainly classified into structural chromosomal aberrations and copy number alterations, giving rise to aneuploid karyotypes. The increasing detection of these genetic changes allowed the description of specific tumor entities and the associated patterns of gene expression. In fact, tumor-specific landscapes of gross genomic copy number changes, including aneuploidies of entire chromosome arms and chromosomes result in a global deregulation of the transcriptome of cancer cells. Furthermore, the molecular characterization of cytogenetic abnormalities has provided insights into the mechanisms of tumorigenesis and has, in a few instances, led to the clinical implementation of effective diagnostic and prognostic tools, as well as treatment strategies that target a specific genetic abnormality.

Pharmacokinetics of Selected Anticancer Drugs in Elderly Cancer Patients: Focus on Breast Cancer

Background: Elderly patients receiving anticancer drugs may have an increased risk to develop treatment-related toxicities compared to their younger peers. However, a potential pharmacokinetic (PK) basis for this increased risk has not consistently been established yet. Therefore, the objective of this study was to systematically review the influence of age on the PK of anticancer agents frequently administered to elderly breast cancer patients. Methods: A literature search was performed using the PubMed electronic database, Summary of Product Characteristics (SmPC) and available drug approval reviews, as published by EMA and FDA. Publications that describe age-related PK profiles of selected anticancer drugs against breast cancer, excluding endocrine compounds, were selected and included. Results: This review presents an overview of the available data that describe the influence of increasing age on the PK of selected anticancer drugs used for the treatment of breast cancer. Conclusions: Selected published data revealed differences in the effect and magnitude of increasing age on the PK of several anticancer drugs. There may be clinically-relevant, age-related PK differences for anthracyclines and platina agents. In the majority of cases, age is not a good surrogate marker for anticancer drug PK, and the physiological state of the individual patient may better be approached by looking at organ function, Charlson Comorbidity Score or geriatric functional assessment.

A Value-Based Approach to Treatment of HER2-Positive Breast Cancer: Examining the Evidence

Over the past decade, treatment of HER2-positive breast cancer has been revolutionized with the introduction of targeted therapies. Survival in both early and advanced HER2-positive breast cancer has improved significantly. With evidence for major clinical benefit, it is imperative that health systems evaluate new treatments to maximize the value of health expenditures. Physicians, funding agencies, and policy makers are tasked with analyzing available evidence to ensure that each individual patient receives the optimal treatment in a resource-challenged environment.

Ado-Trastuzumab Emtansine Targets Hepatocytes Via Human Epidermal Growth Factor Receptor 2 to Induce Hepatotoxicity

Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate (ADC) approved for the treatment of HER2-positive metastatic breast cancer. It consists of trastuzumab, a humanized mAb directed against HER2, and a microtubule inhibitor, DM1, conjugated to trastuzumab via a thioether linker. Hepatotoxicity is one of the serious adverse events associated with T-DM1 therapy. Mechanisms underlying T-DM1-induced hepatotoxicity remain elusive. Here, we use hepatocytes and mouse models to investigate the mechanisms of T-DM1-induced hepatotoxicity. We show that T-DM1 is internalized upon binding to cell surface HER2 and is colocalized with LAMP1, resulting in DM1-associated cytotoxicity, including disorganized microtubules, nuclear fragmentation/multiple nuclei, and cell growth inhibition. We further demonstrate that T-DM1 treatment significantly increases the serum levels of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase in mice and induces inflammation and necrosis in liver tissues, and that T-DM1-induced hepatotoxicity is dose dependent. Moreover, the gene expression of TNFα in liver tissues is significantly increased in mice treated with T-DM1 as compared with those treated with trastuzumab or vehicle. We propose that T-DM1-induced upregulation of TNFα enhances the liver injury that may be initially caused by DM1-mediated intracellular damage. Our proposal is underscored by the fact that T-DM1 induces the outer mitochondrial membrane rupture, a typical morphologic change in the mitochondrial-dependent apoptosis, and mitochondrial membrane potential dysfunction. Our work provides mechanistic insights into T-DM1-induced hepatotoxicity, which may yield novel strategies to manage liver injury induced by T-DM1 or other ADCs.

Effect of hormone therapy on long-term outcomes of patients with human epidermal growth factor receptor 2- and hormone receptor-positive metastatic breast cancer: real world experience in China

BACKGROUND

Among human epidermal growth factor receptor 2 (HER2)-positive breast cancer, more than half are also hormone receptor (HR)-positive. Although HR is a predictive factor for the efficacy of hormone therapy, there are still some uncertainties in regard to the effects on patients with HR-positive and HER2-positive metastatic breast cancers due to the potential resistance to hormone therapy caused by co-expression of HR and HER2. There are no clinical trials directly comparing the efficacy of hormonal therapy with chemotherapy.

MATERIALS AND METHODS

To examine the real-world effect of hormone therapy on patients with HR-positive and HER2-positive metastatic breast cancers, a cross-sectional study of a representative sample of the Chinese population was conducted. The study included 113 patients who received first-line and second-line palliative treatment between 2005 and 2010 in the Cancer Institute and Hospital, Chinese Academy of Medical Science. The effect of hormone therapy on overall survival (OS) was studied.

RESULTS

The patients who received hormone therapy (n=51) had better overall survival in contrast to those who received chemotherapy with anti-HER2 therapy (n=62) in first- or second-line treatment. The difference was of borderline statistical significance (51.8m vs 31.9m, p=0.065). In addition, the effect of hormone therapy did not differ significantly with other prognostic factors, including age (≤50 years or >50 years), disease free survival (≥2 years or < 2 years) and site of metastasis (visceral or bone/soft tissue). On multivariate analysis, administration of hormone therapy was associated with a trend toward a favorable prognosis (p=0.148, HR=0.693, 95%CI 0.422-1.139). Age more than 50 years was the sole independent harmful prognostic factor (p<0.001, HR=2.797, 95%CI 1.676-4.668).

CONCLUSIONS

Our data suggest that hormonel therapy may improve outcomes of the patients with ER-positive and HER2-positive metastatic breast cancer.

A review of HER2-targeted therapy in breast and ovarian cancer: lessons from antiquity - CLEOPATRA and PENELOPE

Although breast and ovarian cancer have notable distinctions, there may exist parallel pathways that can be exploited for therapeutic gain. For example, the therapeutic arena in breast cancer has benefited greatly from available endocrine therapies as well as novel drugs designed to target the HER2 receptor, including trastuzumab, lapatinib, T-DM1 and pertuzumab. CLEOPATRA, a Phase III randomized clinical trial studying pertuzumab in women with HER2-amplified metastatic breast cancer, was practice-changing in 2014. Its counterpart, the Phase III randomized PENELOPE trial, was activated following promising Phase II data and studied pertuzumab in an enriched ovarian cancer patient population with low HER3 mRNA. This review will trace the development of anti-HER2 therapies in breast and ovarian cancer.

Breast cancer brain metastases: the last frontier

Breast cancer is a common cause of brain metastases, with metastases occurring in at least 10–16 % of patients. Longer survival of patients with metastatic breast cancer and the use of better imaging techniques are associated with an increased incidence of brain metastases. Unfortunately, patients who develop brain metastases tend to have poor prognosis with short overall survival. In addition, brain metastases are a major cause of morbidity, associated with progressive neurologic deficits that result in a reduced quality of life. Tumor subtypes play a key role in prognosis and treatment selection. Current therapies include surgery, whole-brain radiation therapy, stereotactic radiosurgery, chemotherapy and targeted therapies. However, the timing and appropriate use of these therapies is controversial and careful patient selection by using available prognostic tools is extremely important. This review will focus on current treatment options, novel therapies, future approaches and ongoing clinical trials for patients with breast cancer brain metastases.

Human epidermal growth factor receptor 2 positive (HER2+) metastatic breast cancer: how the latest results are improving therapeutic options

Human epidermal growth factor receptor 2 positive (HER2+) metastatic breast cancer (MBC) remains an incurable disease, and approximately 25% of patients with HER2+ early breast cancer still relapse after adjuvant trastuzumab-based treatment. HER2 is a validated therapeutic target that remains relevant throughout the disease process. Recently, a number of novel HER2 targeted agents have become available, including lapatinib (a small molecule tyrosine kinase inhibitor of both HER2 and the epidermal growth factor receptor), pertuzumab (a new anti-HER2 monoclonal antibody) and ado-trastuzumab emtansine (T-DM1, a novel antibody-drug conjugate), which provide additional treatment options for patients with HER2+ MBC. The latest clinical trials have demonstrated improved outcome with treatment including pertuzumab or T-DM1 compared with standard HER2 targeted therapy. Here we review the clinical development of approved and investigational targeted agents for the treatment of HER2+ MBC, summarize the latest results of important clinical trials supporting use of these agents in the treatment of HER2+ MBC, and discuss how these results impact therapeutic options in clinical practice.

Optimal management of hormone receptor positive metastatic breast cancer in 2016

Hormone receptor positive tumors represent the most common form of breast cancer and account for most of the deaths from the disease. Endocrine therapy represents the main initial therapeutic strategy for these patients and has been associated with significant clinical benefits in a majority of patients. While in early stages endocrine therapy is administered as part of a curative approach once clinical metastases develop, the disease is considered incurable and the main management objectives are tumor control and quality of life. The two major clinical paradigms of always indicating endocrine therapy in the absence of visceral crises and sequencing endocrine treatments have been guiding our therapeutic approach to these patients. However, for many decades, we have delivered endocrine therapy with a 'one size fits all' approach by applying agents that interfere with hormone receptor signaling equally in every clinical patient scenario. We have been unable to incorporate the well-known biologic principle of different degrees of hormone receptor dependency in our therapeutic recommendations. Recent developments in the understanding of molecular interactions of hormone signaling with other important growth factor, metabolic and cell division pathways have opened the possibility of improving results by modulating hormone signaling and interfering with resistance mechanisms yet to be fully understood. Unfortunately, limitations in the design of trials conducted in this area have made it difficult to develop predictive biomarkers and most of the new combinations with targeted agents, even though showing improvements in clinical endpoints, have been directed to an unselected population of patients. In this review we explore some of the current and most relevant literature in the management of hormone receptor positive advance breast cancer.

Dissecting the Heterogeneity of Treatment Response in First-Episode Schizophrenia

The Mental Health Centers for Intervention Development and Applied Research (CIDAR) program prioritized research to provide an evidence base for biomarker development. At the Zucker Hillside Hospital (ZHH), our CIDAR grant supported research on a comprehensive investigation of treatment response and outcome in first episode schizophrenia. Results provide evidence that baseline neuroimaging, neurocognitive, and genetic measures are significantly associated with clinical response to treatment, and that our currently available interventions can effectively treat aspects of psychotic illness, as well as potentially reduce comorbidity associated with illness. Future research may include combining modalities to more robustly predict response and identify treatment targets, as well as to further develop more effective intervention strategies for these devastating and disabling disorders.

NatHER: protocol for systematic evaluation of trends in survival among patients with HER2-positive advanced breast cancer

BACKGROUND

Human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) is an aggressive form of breast cancer and is historically associated with poor outcomes compared with HER2-negative MBC. Since 1998, four drugs have been globally approved for the targeted treatment of HER2-positive MBC. Additional advances in patient care-such as improved breast cancer screening, HER2 testing, and supportive care-have also occurred. The objective of this systematic review and meta-analysis is to determine whether there has been a cumulative change in survival over time in patients with HER2-positive advanced breast cancer based on results from interventional clinical trials (ICTs) and observational studies and to compare outcomes across these types of studies.

METHODS/DESIGN

A systematic search of Medline, EMBASE, and the Cochrane Central Register of Controlled Trials will be performed. Two investigators will independently assess each abstract for inclusion. English language reports of ICTs and observational studies that include patients with HER2-positive advanced breast cancer from 1987 onwards will be considered. The primary outcome of interest is overall survival; secondary outcomes include progression-free survival and safety. Data on clinical outcomes, as well as on study design, study population, treatment/intervention, methodological quality, and outcomes, will be extracted using a structured codebook developed by the authors for this study. Standard and cumulative random effects meta-analysis will be performed to derive pooled risk estimates, both overall and by study design, controlling for covariates such as aggregate demographic and clinical characteristics of patients, treatment/intervention, and study characteristics. Heterogeneity of studies will be evaluated using the I(2) statistic. Differences in risk estimates by quality characteristics will be performed using meta-regression.

DISCUSSION

This study will evaluate current and evolving trends in survival associated with HER2-positive advanced breast cancer over nearly 30 years and will build upon prior, less comprehensive, systematic analyses. This information is important to patients, healthcare providers, and researchers, particularly in the advanced disease setting, in which new therapies have been recently approved. Including observational studies allows us to evaluate real-world effectiveness; useful information will be gained by comparing findings from observational studies with those from ICTs.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014014345.

Impact of prior anthracycline or taxane use on eribulin effectiveness as first-line treatment for metastatic breast cancer: results from two phase 2, multicenter, single-arm studies

Eribulin mesylate has efficacy in patients who have received ≥2 prior chemotherapies for metastatic breast cancer (MBC) including an anthracycline and taxane. Phase 2 trials showed clinical activity and acceptable tolerability of first-line eribulin (HER2− MBC; Study 206) and eribulin plus trastuzumab (HER2+ MBC; Study 208). Prespecified analyses evaluated efficacy by prior anthracycline and/or taxane use. Patients received eribulin mesylate (1.4 mg/m² IV; Days 1 and 8) and, in Study 208, trastuzumab (8 mg/kg IV/Cycle 1, then 6 mg/kg; Day 1) in 21-day cycles. Endpoints included objective response rate (ORR), progression-free survival (PFS), and tolerability. In Study 206 (N = 56), 48 % of patients had received prior anthracycline, 46 % prior taxane, 36 % prior anthracycline and taxane, and 41 % were chemotherapy-naïve. In Study 208 (N = 52), these percentages were 21, 44, 17, and 52 %, respectively. In Study 206, ORR and median PFS were similar for anthracycline-pretreated (25.9 %, 5.8 months), taxane-pretreated (26.9 %, 5.8 months), anthracycline- and taxane-pretreated (25.0 %, 6.7 months), and anthracycline/taxane-naïve patients (30.4 %, 7.6 months). In Study 208, ORR/median PFS were 63.6 %/6.7 months among anthracycline-pretreated patients, 56.5 %/6.8 months among taxane-pretreated patients, 55.6 %/5.9 months among anthracycline- and taxane-pretreated patients, and 81.5 %/13.1 months among anthracycline/taxane-naïve patients. Tolerability was generally similar among subgroups. In these studies, first-line eribulin in HER2− MBC and eribulin/trastuzumab in HER2+ MBC was effective with acceptable tolerability, regardless of prior anthracycline/taxane treatment. Prior chemotherapy was associated with lower ORR and shorter PFS with eribulin/trastuzumab in HER2+ MBC but not with eribulin in HER2− MBC.

Second-Line Treatment of Her2-Positive Metastatic Breast Cancer: Trastuzumab beyond Progression or Lapatinib? A Population Based Cohort Study

Background

The relative efficacy of lapatinib vs. continuing trastuzumab beyond progression (TBP) in HER2-positive metastatic breast cancer (MBC) patients, who progressed on first-line trastuzumab, is still unclear. The objective of this population based cohort study was to compare outcomes of lapatinib vs. TBP in daily practice.

Methods

All HER2-positive MBC patients who began second-line anti HER2 therapy between 1st January 2010 and 30th August 2013 were selected from Clalit Health Services’ (CHS) electronic database. Available data on patient and disease characteristics and treatments were analyzed. The primary endpoint was overall survival (OS). Outcomes were compared using the Kaplan-Meier (log-rank) method and Cox proportional hazards model.

Results

64 patients received second-line lapatinib and 93 TBP. The two treatment groups were similar in age and co-morbidity rates, but differed in proportion of prior adjuvant trastuzumab (lapatinib: 29.7%, TBP: 16.1%, P = 0.043) and rates of prior brain metastases (lapatinib: 32.8%, TBP: 10.8%, P = 0.01). Lapatinib median OS was 13.0 months (95% CI: 9.5–16.5) vs. 31.0 for TBP (95% CI: 20.6–41.4), P<0.001. On multivariate analysis, longer OS was preserved for TBP, after controlling for differences in age, adjuvant trastuzumab, duration of first-line trastuzumab therapy, brain metastases, visceral metastases and hormonal treatment [Hazard Ratio (HR) = 0.63, 95% CI: 0.40–0.99, P = 0.045].

Conclusion

In this comparative cohort study, OS of HER2-positive MBC patients treated with TBP was significantly longer than with lapatinib. These results might be especially relevant in settings where ado-trastuzumab-emtansine (TDM-1), the current preferred agent in this setting, is not available yet for patients.

Targeting HER2 for the treatment of breast cancer

HER2 (ErbB2), a member of the HER family of tyrosine kinase receptors (HER1-4), is a major driver of tumor growth in 20% of breast cancers. Treatment with the anti-HER2 monoclonal antibody trastuzumab has revolutionized the outcome of patients with this aggressive breast cancer subtype, but intrinsic and acquired resistance is common. Growing understanding of the biology and complexity of the HER2 signaling network and of potential resistance mechanisms has guided the development of new HER2-targeted agents. Combinations of these drugs to more completely inhibit the HER receptor layer, or combining HER2-targeted agents with agents that target downstream signaling, alternative pathways, or components of the host immune system, are being vigorously investigated in the preclinical and clinical settings. As a result, the list of more effective and well tolerated FDA-approved new regimens for patients with HER2+ tumors is constantly growing.

From bench to bedside: What do we know about hormone receptor-positive and human epidermal growth factor receptor 2-positive breast cancer?

Breast cancer is a heterogeneous disease. Thanks to extensive efforts from research scientists and clinicians, treatment for breast cancer has advanced into the era of targeted medicine. With the use of several well-established biomarkers, such as hormone receptors (HRs) (i.e., estrogen receptor [ER] and progesterone receptor [PgR]) and human epidermal growth factor receptor-2 (HER2), breast cancer patients can be categorized into multiple subgroups with specific targeted treatment strategies. Although therapeutic strategies for HR-positive (HR+) HER2-negative (HER2-) breast cancer and HR-negative (HR-) HER2-positive (HER2+) breast cancer are well-defined, HR+ HER2+ breast cancer is still an overlooked subgroup without tailored therapeutic options. In this review, we have summarized the molecular characteristics, etiology, preclinical tools and therapeutic options for HR+ HER2+ breast cancer. We hope to raise the attention of both the research and the medical community on HR+ HER2+ breast cancer, and to advance patient care for this subtype of disease.

ADAPT, a Novel Scaffold Protein-Based Probe for Radionuclide Imaging of Molecular Targets That Are Expressed in Disseminated Cancers

Small engineered scaffold proteins have attracted attention as probes for radionuclide-based molecular imaging. One class of these imaging probes, termed ABD-Derived Affinity Proteins (ADAPT), has been created using the albumin-binding domain (ABD) of streptococcal protein G as a stable protein scaffold. In this study, we report the development of a clinical lead probe termed ADAPT6 that binds HER2, an oncoprotein overexpressed in many breast cancers that serves as a theranostic biomarker for several approved targeting therapies. Surface-exposed amino acids of ABD were randomized to create a combinatorial library enabling selection of high-affinity binders to various proteins. Furthermore, ABD was engineered to enable rapid purification, to eradicate its binding to albumin, and to enable rapid blood clearance. Incorporation of a unique cysteine allowed site-specific conjugation to a maleimido derivative of a DOTA chelator, enabling radionuclide labeling, ¹¹¹In for SPECT imaging and ⁶⁸Ga for PET imaging. Pharmacologic studies in mice demonstrated that the fully engineered molecule (111)In/⁶⁸Ga-DOTA-(HE)3-ADAPT6 was specifically bound and taken up by HER2-expressing tumors, with a high tumor-to-normal tissue ratio in xenograft models of human cancer. Unbound tracer underwent rapid renal clearance followed by high renal reabsorption. HER2-expressing xenografts were visualized by gamma-camera or PET at 1 hour after infusion. PET experiments demonstrated feasibility for discrimination of xenografts with high or low HER2 expression. Our results offer a preclinical proof of concept for the use of ADAPT probes for noninvasive in vivo imaging.

Treatment of HER2 positive advanced breast cancer with T-DM1: A review of the literature

BACKGROUND

Trastuzumab emtansine (T-DM1), a new agent developed for the treatment of HER2-positive breast cancer, is an antibody-drug conjugate with a complex compound obtained by the conjugation of trastuzumab, a stable thioether linker, and the potent cytotoxic drug maytansine-derivate(DM1), which inhibits cell division and induces cell death.

FIELD OF STUDY

PubMed database, ESMO, ASCO, San Antonio Breast Cancer Symposium Meeting abstracts and clinicaltrials.gov were searched using the terms "Anti-HER2 treatment breast cancer and trastuzumab emtansine (T-DM1) "; papers considered relevant for the aim of this review were selected.

FINDINGS/RESULTS

The phase I trials have determined the safe dosing range of T-DM1, established at 3.6 mg/kg every 3 weeks. The phase III randomized EMILIA and TR3RESA trials have shown that T-DM1 provides objective tumor responses and significantly improves progression free survival and overall survival in HER2-positive metastatic breast cancer patients previously treated with anti-HER2-based regimens. The ongoing phase III trials KAITLIN and KATHERINE will give us further information about the place T-DM1 should occupy in the treatment of patients with early stage HER2-positive breast cancer. In this review we analyze the most relevant clinical trials conducted with T-DM1 and the role of this compound in the management of advanced breast cancer.

CONCLUSION

T-DM1 has shown clinically relevant activity in the treatment of HER2-positive breast cancer patients after progression on trastuzumab and taxane based therapy, both in the second line treatment setting and after early relapse on adjuvant trastuzumab therapy. This is accompanied by a favorable safety and tolerability profile.

Are predictions of cancer response to targeted drugs, based on effects in unrelated tissues, the ‘Black Swan’ events?

Adverse effects of targeted drugs on normal tissues can predict the cancer response. Rash correlates with efficacy of erlotinib, cetuximab and gefitinib and onset of arterial hypertension with response to bevacizumab, sunitinib, axitinib and sorafenib, possible examples of ‘Black Swan’ events, unexpected scientific observations, as described by Karl Popper in 1935. The proposition is that our patients have individual intrinsic variants of cell growth control, important for tumor response and adverse effects on tumor-unrelated tissue. This means that the lack of predictive side effects in healthy tissue is linked with poor results of tumor therapy when tumor resistance is caused by mechanisms that protect all cells of that patient from the targeted drug effects.

Use of Biomarkers to Guide Decisions on Systemic Therapy for Women With Metastatic Breast Cancer: American Society of Clinical Oncology Clinical Practice Guideline

PURPOSE

To provide recommendations on the appropriate use of breast tumor biomarker assay results to guide decisions on systemic therapy for metastatic breast cancer.

METHODS

A literature search and prospectively defined study selection identified systematic reviews, meta-analyses, randomized controlled trials (RCTs), prospective-retrospective studies, and prospective comparative observational studies published from 2006 through September 2014.

RESULTS

The literature search revealed 17 articles that met criteria for further review: 11 studies reporting discordances between primary tumors and metastases in expression of hormone receptors or human epidermal growth factor receptor 2 (HER2), one RCT that addressed the use of a biomarker to decide whether to change or continue a treatment regimen, and five prospective-retrospective studies that evaluated the clinical utility of biomarkers.

RECOMMENDATIONS

In patients with accessible metastases, biopsy for confirmation of disease process and retesting of estrogen receptor, progesterone receptor, and HER2 status should be offered, but evidence is lacking to determine whether changing anticancer treatment on the basis of change in receptor status affects clinical outcomes. With discordance of results between primary and metastatic tissues, the Panel consensus is to use preferentially the estrogen receptor, progesterone receptor, and HER2 status of the metastasis to direct therapy if supported by the clinical scenario and patient's goals for care. Carcinoembryonic antigen, cancer antigen 15-3, and cancer antigen 27-29 may be used as adjunctive assessments, but not alone, to contribute to decisions regarding therapy. Recommendations for tumor rebiopsy and use of circulating tumor markers are based on clinical experience and Panel informal consensus in the absence of studies designed to evaluate the clinical utility of the markers. As such, it is also reasonable for clinicians to not use these markers as adjunctive assessments.

Phase II Study of Lapatinib in Combination With Trastuzumab in Patients With Human Epidermal Growth Factor Receptor 2-Positive Metastatic Breast Cancer: Clinical Outcomes and Predictive Value of Early [18F]Fluorodeoxyglucose Positron Emission Tomography Imaging (TBCRC 003)

PURPOSE

Lapatinib plus trastuzumab improves outcomes relative to lapatinib alone in heavily pretreated, human epidermal growth factor receptor 2-positive metastatic breast cancer (MBC). We tested the combination in the earlier-line setting and explored the predictive value of [(18)F]fluorodeoxyglucose positron emission tomography ([(18)F]FDG-PET) for clinical outcomes.

PATIENTS AND METHODS

Two cohorts were enrolled (cohort 1: no prior trastuzumab for MBC and ≥ 1 year from adjuvant trastuzumab, if given; cohort 2: one to two lines of chemotherapy including trastuzumab for MBC and/or recurrence < 1 year from adjuvant trastuzumab). The primary end point was objective response rate by RECIST v1.0; secondary end points included clinical benefit rate (complete response plus partial response plus stable disease ≥ 24 weeks) and progression-free survival. [(18)F]FDG-PET scans were acquired at baseline, week 1, and week 8. Associations between metabolic response and clinical outcomes were explored.

RESULTS

Eighty-seven patients were registered (85 were evaluable for efficacy). The confirmed objective response rate was 50.0% (95% CI, 33.8% to 66.2%) in cohort 1 and 22.2% (95% CI, 11.3% to 37.3%) in cohort 2. Clinical benefit rate was 57.5% (95% CI, 40.9% to 73.0%) in cohort 1 and 40.0% (95% CI, 25.7% to 55.7%) in cohort 2. Median progression-free survival was 7.4 and 5.3 months, respectively. Lack of week-1 [(18)F]FDG-PET/computed tomography ([(18)F]FDG-PET/CT) response was associated with failure to achieve an objective response by RECIST (negative predictive value, 91% [95% CI, 74% to 100%] for cohort 1 and 91% [95% CI, 79% to 100%] for cohort 2).

CONCLUSION

Early use of lapatinib and trastuzumab is active in human epidermal growth factor receptor 2-positive MBC. Week-1 [(18)F]FDG-PET/CT may allow selection of patients who can be treated with targeted regimens and spared the toxicity of chemotherapy.

Subcutaneous Trastuzumab for HER2-positive Breast Cancer - Evidence and Practical Experience in 7 German Centers

A subcutaneous formulation of trastuzumab to treat patients with HER2-positive breast cancer is available since August 2013. The subcutaneous formulation is administered as a fixed dose of 600 mg over a period of up to 5 minutes. The HannaH trial compared subcutaneous with intravenous administration and found comparable pharmacokinetics, efficacy and tolerability for both administration forms of trastuzumab in the neoadjuvant setting. The randomized crossover study PrefHer reported a clear preference from the patient's point of view for subcutaneous over intravenous administration of trastuzumab. The accompanying time-and-motion study reported a reduction concerning the total time spent for the institution as well as for the patient receiving trastuzumab s. c.. The experience of 7 German centers largely corresponded with the results of these studies. Patients expressed a clear preference for subcutaneous trastuzumab administration, with the time saved by the subcutaneous administration route cited as the greatest benefit. Although the existing reimbursement terms mean that centers will receive a lower remuneration, the centers' overall evaluation of the subcutaneous administration route for trastuzumab was overwhelmingly positive. The greatest benefit cited by the centers was the flexibility in scheduling patient appointments. This increased flexibility improved conditions in some centers which were experiencing pressures due to a shortage of staff, particularly at peak times. The general consensus, however, was that the remuneration systems for oncological treatments urgently need to be amended to ensure that the real costs of treatment are covered, even if the administration route has changed.

Biomarkers in Breast Cancer: Where Are We and Where Are We Going?

Biomarkers play an important role in the detection and management of patients with breast cancer. Thus, BRCA1/2 mutation testing is used for risk assessment in families with a high prevalence of breast and ovarian cancer. Following a diagnosis of breast cancer, measurement of multi-analyte profiles such as uPA/PAI-1 or Oncotype DX may be used for determining prognosis and identifying lymph node-negative patients who may be spared from having to receive adjuvant chemotherapy. Other -gene tests such as the PAM50 ROR, Breast Cancer Index, and EndoPredict have been reported to predict the development of late recurrences and thus may be of value in selecting patients for extended hormone therapy. Mandatory assays include estrogen receptors for identification of endocrine-sensitive cancers and HER2 in selecting patients for treatment with anti-HER2 therapy (e.g., trastuzumab, lapatinib, pertuzumab, and ado-trastuzumab emtansine). Finally, serum biomarkers such as CA 15-3 or CEA may be used in monitoring therapy in patients with advanced disease receiving systemic therapy. Promising new biomarkers undergoing evaluation include circulating tumor cells and circulating tumor-derived DNA.

Patterns of Care and Clinical Outcomes of First-Line Trastuzumab-Based Therapy in HER2-Positive Metastatic Breast Cancer Patients Relapsing After (Neo)Adjuvant Trastuzumab: An Italian Multicenter Retrospective Cohort Study

BACKGROUND

We evaluated the patterns of care and clinical outcomes of metastatic breast cancer patients treated with first-line trastuzumab-based therapy after previous (neo)adjuvant trastuzumab.

MATERIALS AND METHODS

A total of 416 consecutive, HER2-positive metastatic breast cancer patients who had received first-line trastuzumab-based therapy were identified at 14 Italian centers. A total of 113 patients had presented with de novo stage IV disease and were analyzed separately. Dichotomous clinical outcomes were analyzed using logistic regression and time-to-event outcomes using Cox proportional hazards models.

RESULTS

In the 202 trastuzumab-naïve patients and 101 patients with previous trastuzumab exposure, we observed the following outcomes, respectively: overall response rate, 69.9% versus 61.3% (adjusted odds ratio [OR], 0.62; p = .131), clinical benefit rate, 79.1% versus 72.5% (adjusted OR, 0.73; p = .370), median progression-free survival (PFS), 16.1 months versus 12.0 months (adjusted hazards ratio [HR], 1.33; p = .045), and median overall survival (OS), 52.2 months versus 48.2 months (adjusted HR, 1.18; p = .404). Patients with a trastuzumab-free interval (TFI) <6 months, visceral involvement, and hormone receptor-negative disease showed a worse OS compared with patients with a TFI of ≥6 months (29.5 vs. 48.3 months; p = .331), nonvisceral involvement (48.0 vs. 60.3 months; p = .270), and hormone receptor-positive disease (39.8 vs. 58.6 months; p = .003), respectively.

CONCLUSION

Despite the inferior median PFS, trastuzumab-based therapy was an effective first-line treatment for patients relapsing after (neo)adjuvant trastuzumab. Previous trastuzumab exposure and the respective TFI, type of first site of disease relapse, and hormone receptor status should be considered in the choice of the best first-line treatment option for HER2-positive metastatic breast cancer patients.

Can maintenance trastuzumab be stopped in patients with HER2-positive metastatic breast cancer?

Trastuzumab has significantly improved the median survival of patients with HER2-positive breast cancer. In metastatic disease, maintenance trastuzumab is usually given after tumour response has been achieved with the combination of chemotherapy and trastuzumab, with the aim of prolonging time to disease progression. We report a case where a durable complete response (CR) was achieved without maintenance trastuzumab. In the absence of consensus guidelines, it is difficult to recommend which HER2-positive patients with metastatic breast cancer after CR will benefit from withdrawing maintenance trastuzumab therapy and when this could be considered.

Safety, pharmacokinetics and efficacy findings in an open-label, single-arm study of weekly paclitaxel plus lapatinib as first-line therapy for Japanese women with HER2-positive metastatic breast cancer

Background

Lapatinib is the human epidermal growth factor receptor 2 (HER2) targeting agent approved globally for HER2-positive metastatic breast cancer (MBC). The efficacy, safety and pharmacokinetics (PK) of lapatinib combined with paclitaxel (L+P) were investigated in this study, to establish clear evidence regarding the combination in Japanese patients.

Methods

In this two-part, single-arm, open-label study, the tolerability of L+P as first-line treatment in Japanese patients with HER2-positive MBC was evaluated in six patients in the first part, and the safety, efficacy and PK were evaluated in a further six patients (making a total of twelve patients) in the second part. Eligible women were enrolled and received lapatinib 1500 mg once daily and paclitaxel 80 mg/m² weekly for at least 6 cycles.

Results

The only dose-limiting toxicity reported was Grade 3 diarrhea in one patient. The systemic exposure to maximum plasma concentration and area under the plasma concentration curve (AUC) for lapatinib, as well as the AUC of paclitaxel, were increased when combined. The most common adverse events (AEs) related to the study treatment were alopecia, diarrhea and decreased hemoglobin. The majority of drug-related AEs were Grade 1 or 2. The median overall survival was 35.6 months (95 % confidence interval 23.9, not reached). The response rate and clinical benefit rate were both 83 % (95 % confidence interval 51.6, 97.9).

Conclusions

The L+P treatment was well tolerated in Japanese patients with HER2-positive MBC. Although the PK profiles of lapatinib and paclitaxel influenced each other, the magnitudes were not greatly different from those in non-Japanese patients.

Targeted therapy in her2-positive metastatic breast cancer: a review of the literature

Breast tumours positive for her2 (human epidermal growth factor receptor 2) represent approximately 20% of all breast cancer cases and are associated with an aggressive natural history. The advent of targeted anti-her2 therapies has dramatically improved disease control and survival in patients with metastatic her2-positive breast cancer. Targeted agents are now considered the standard of care in the first-line setting and beyond. The present review summarizes the currently available data on targeted anti-her2 therapies from completed randomized phase iii clinical trials and briefly discusses emerging advances that will address unmet needs in metastatic her2-positive breast cancer.

Combination pertuzumab, trastuzumab, and taxane for metastatic breast cancer after first progression: a single institution’s experience

Background

The addition of pertuzumab to trastuzumab and taxane therapy was shown to be an effective first-line treatment for patients with HER2-positive metastatic breast cancer.

Objective

Describe the progression-free survival of pertuzumab, trastuzumab, and taxane therapy for previously treated HER2-positive metastatic breast cancer.

Methods

This case-series reviews 19 patients with metastatic breast cancer receiving treatment with pertuzumab, trastuzumab, taxane after progression and exposure to previous lines of HER2-directed therapy. Progression-free survival and adverse effects such as changes in ejection fraction and episodes of neutropenic fever were assessed.

Results

The median progression-free survival of pertuzumab, trastuzumab, taxane therapy for previously treated metastatic breast cancer was 4.1 months. The mean baseline left ventricular ejection fraction change experienced by patients was –1%. Neutropenic fever events were not encountered.

Conclusions

Pertuzumab, trastuzumab, and taxane therapy seems to confer progression-free survival benefit for previously treated metastatic breast cancer. The use of the dual anti-HER2 antibodies, pertuzumab and trastuzumab, in addition to cytotoxic chemotherapy agents for previously treated metastatic breast cancer should be further evaluated.

Impact of breast cancer subtypes and patterns of metastasis on outcome

Clinical outcome of patients with stage IV breast cancer is dependent on tumor biology, extent, and localization of metastases. Routine imaging diagnostics for distant metastasis is not recommended by the national guidelines for breast cancer follow-up. In this study, we evaluated different patterns of metastases of cancer subtypes in order to generate hypotheses on individualization of follow-up after breast cancer in the adjuvant setting. Patients of the Regional Breast Cancer Center Dresden diagnosed within the years 2006-2011 were classified into the five intrinsic subtypes luminal A (ER+, Her2-, G1/2), luminal B/Her2 negative (ER+, Her2-, G3), triple positive (ER+, PR+, Her2+), Her2-enriched (ER-, Her2+), and triple negative (ER-, PR-, Her2-) and with a median follow-up of 45 months. Tumor stage at time of first diagnosis of breast cancer as well as time and site of metastasis at first diagnosis of distant metastatic disease was analyzed. Tumor specimen of 2284 female patients with primary breast cancer was classified into five subtypes. Distant recurrence-free survival at 3 years was most unfavorable in Her2-enriched (66.8 %), triple negative (75.9 %), and triple-positive breast cancer (81.7 %). The same subtypes most frequently presented with visceral metastases only at first presentation: Her2-enriched 46.9 %, triple negative 45.5 %, and triple-positive breast cancer 37.5 %. Longest median survival of 2.3 years was seen in luminal A and in Her2-enriched metastatic disease, respectively. Median survival was significantly better in the luminal A, Her2-enriched, and triple-positive subtype compared to triple-negative breast cancer (p < 0.005). Differences in time to metastatic disease, first localization of metastases, and overall survival after diagnosis of metastatic disease were shown. Considering new targeted therapies and the option of surgery of oligometastases, screening for visceral metastases might be reasonable after diagnosis of Her2-positive subtypes.

Systemic treatment approaches in her2-negative advanced breast cancer-guidance on the guidelines

Despite advancements in the treatment of early-stage breast cancer, many patients still develop disease recurrence; others present with de novo metastatic disease. For most patients with advanced breast cancer, the primary treatment intent is noncurative-that is, palliative-in nature. The goals of treatment should therefore focus on maximizing symptom control and extending survival. Treatments should be evaluated on an individualized basis in terms of evidence, but also with full respect for the wishes of the patient in terms of acceptable toxicity. Given the availability of extensive reviews on the roles of endocrine therapy and her2 (human epidermal growth factor receptor 2)-targeted therapies for advanced disease, we focus here mainly on treatment guidelines for the non-endocrine management of her2-negative advanced breast cancer in a Canadian health care context.

Molecular diagnostic testing in breast cancer

OBJECTIVES

An overview of molecular tests used in the treatment of breast cancer, organized by stage and clinical condition.

DATA SOURCES

Systematic review of scientific literature, guideline recommendations, and data published by test manufacturers.

CONCLUSION

Several molecular tests that analyze expression of cancer-related genes have been validated in clinical trials and are recommended by clinical practice guidelines to inform diagnosis and treatment decisions for personalized interventions.

IMPLICATIONS FOR NURSING PRACTICE

Molecular testing has become an important part of patient care for those with breast cancer. Oncology nurses must understand this methodology to prescribe tests, interpret the results, and provide guidance to patients.

HER2-positive metastatic breast cancer: a changing scenario

Adjuvant trastuzumab (AT) dramatically improved HER2-positive breast cancer prognosis. Relapsed disease after AT has different patterns and information is available from observational studies. In this Review Chemotherapy regimens combined to anti-HER2 blockade are discussed, focusing in particular the role of anthracyclines, taxanes and capecitabine. The use of trastuzumab beyond progression and the role of other anti-HER2 agents like lapatinib, pertuzumab and T-DM1 are explored, as also dual blockade and in trastuzumab resistant Patients. Metastatic "de novo" HER2 Luminal (co-expression of HER2 and hormone receptors) Patients are eligible for anastrozole and trastuzumab but if pretreated with trastuzumab they are also eligible for lapatinib and letrozole. In any case endocrine treatment plays a complementary role to chemotherapy which remains pivotal. The last topic explored is treatment options for patients with brain metastases where both trastuzumab given concurrent with radiotherapy or lapatinib and capecitabine appear as potentially active.

Retinoic acid receptors: from molecular mechanisms to cancer therapy

Retinoic acid (RA), the major bioactive metabolite of retinol or vitamin A, induces a spectrum of pleiotropic effects in cell growth and differentiation that are relevant for embryonic development and adult physiology. The RA activity is mediated primarily by members of the retinoic acid receptor (RAR) subfamily, namely RARα, RARβ and RARγ, which belong to the nuclear receptor (NR) superfamily of transcription factors. RARs form heterodimers with members of the retinoid X receptor (RXR) subfamily and act as ligand-regulated transcription factors through binding specific RA response elements (RAREs) located in target genes promoters. RARs also have non-genomic effects and activate kinase signaling pathways, which fine-tune the transcription of the RA target genes. The disruption of RA signaling pathways is thought to underlie the etiology of a number of hematological and non-hematological malignancies, including leukemias, skin cancer, head/neck cancer, lung cancer, breast cancer, ovarian cancer, prostate cancer, renal cell carcinoma, pancreatic cancer, liver cancer, glioblastoma and neuroblastoma. Of note, RA and its derivatives (retinoids) are employed as potential chemotherapeutic or chemopreventive agents because of their differentiation, anti-proliferative, pro-apoptotic, and anti-oxidant effects. In humans, retinoids reverse premalignant epithelial lesions, induce the differentiation of myeloid normal and leukemic cells, and prevent lung, liver, and breast cancer. Here, we provide an overview of the biochemical and molecular mechanisms that regulate the RA and retinoid signaling pathways. Moreover, mechanisms through which deregulation of RA signaling pathways ultimately impact on cancer are examined. Finally, the therapeutic effects of retinoids are reported.

HER2-directed therapy: current treatment options for HER2-positive breast cancer

Over the past decade, the management of HER2-positive breast cancer has evolved dramatically. In addition to advances in screening, genetic testing, imaging, surgical and radiation techniques, innovations in medical therapy including widespread use of HER2-directed therapy in early and advanced breast cancer have revolutionized breast cancer care and changed the natural history of HER2-positive breast cancer. A substantial number of HER2-targeted agents are being developed including monoclonal antibodies, small molecule inhibitors, and antibody drug conjugates. Trastuzumab is the prototype HER2-directed therapy that was introduced in the late 1990s for the management of metastatic breast cancer and later showed efficacy in early stage disease. Despite the practice changing impact of trastuzumab and improvement in outcomes of women with HER2-positive breast cancer resistance to trrastuzumab is a major clinical issue, occurring in both early stage and advanced disease, and new treatment strategies are clearly required. Combining HER2-targeted agents and dual HER2 blockade has been successful in early and advanced breast cancer. Furthermore, selected delivery of potent chemotherapeutic agent coupled with HER2 inhibition promises new treatment options. This review is focused on current HER2-directed treatments for women with HER2-positive breast cancer including monoclonal antibodies, small molecule inhibitors, and antibody drug conjugates.