Cardiac safety of trastuzumab in combination with epirubicin and cyclophosphamide in women with metastatic breast cancer

An In Silico Platform to Predict Cardiotoxicity Risk of Anti-tumor Drug Combination with hiPSC-CMs Based In Vitro Study

OBJECTIVE

Antineoplastic agent-induced systolic dysfunction is a major reason for interruption of anticancer treatment. Although targeted anticancer agents infrequently cause systolic dysfunction, their combinations with chemotherapies remarkably increase the incidence. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) provide a potent in vitro model to assess cardiovascular safety. However, quantitatively predicting the reduction of ejection fraction based on hiPSC-CMs is challenging due to the absence of the body's regulatory response to cardiomyocyte injury.

METHODS

Here, we developed and validated an in vitro-in vivo translational platform to assess the reduction of ejection fraction induced by antineoplastic drugs based on hiPSC-CMs. The translational platform integrates drug exposure, drug-cardiomyocyte interaction, and systemic response. The drug-cardiomyocyte interaction was implemented as a mechanism-based toxicodynamic (TD) model, which was then integrated into a quantitative system pharmacology-physiological-based pharmacokinetics (QSP-PBPK) model to form a complete translational platform. The platform was validated by comparing the model-predicted and clinically observed incidence of doxorubicin and trastuzumab-induced systolic dysfunction.

RESULTS

A total of 33,418 virtual patients were incorporated to receive doxorubicin and trastuzumab alone or in combination. For doxorubicin, the QSP-PBPK-TD model successfully captured the overall trend of systolic dysfunction incidences against the cumulative doses. For trastuzumab, the predicted incidence interval was 0.31-2.7% for single-agent treatment and 0.15-10% for trastuzumab-doxorubicin sequential treatment, covering the observations in clinical reports (0.50-1.0% and 1.5-8.3%, respectively).

CONCLUSIONS

In conclusion, the in vitro-in vivo translational platform is capable of predicting systolic dysfunction incidence almost merely depend on hiPSC-CMs, which could facilitate optimizing the treatment protocol of antineoplastic agents.

Management of cardiac disease in cancer patients throughout oncological treatment: ESMO consensus recommendations

Cancer and cardiovascular (CV) disease are the most prevalent diseases in the developed world. Evidence increasingly shows that these conditions are interlinked through common risk factors, coincident in an ageing population, and are connected biologically through some deleterious effects of anticancer treatment on CV health. Anticancer therapies can cause a wide spectrum of short- and long-term cardiotoxic effects. An explosion of novel cancer therapies has revolutionised this field and dramatically altered cancer prognosis. Nevertheless, these new therapies have introduced unexpected CV complications beyond heart failure. Common CV toxicities related to cancer therapy are defined, along with suggested strategies for prevention, detection and treatment. This ESMO consensus article proposes to define CV toxicities related to cancer or its therapies and provide guidance regarding prevention, screening, monitoring and treatment of CV toxicity. The majority of anticancer therapies are associated with some CV toxicity, ranging from asymptomatic and transient to more clinically significant and long-lasting cardiac events. It is critical however, that concerns about potential CV damage resulting from anticancer therapies should be weighed against the potential benefits of cancer therapy, including benefits in overall survival. CV disease in patients with cancer is complex and treatment needs to be individualised. The scope of cardio-oncology is wide and includes prevention, detection, monitoring and treatment of CV toxicity related to cancer therapy, and also ensuring the safe development of future novel cancer treatments that minimise the impact on CV health. It is anticipated that the management strategies discussed herein will be suitable for the majority of patients. Nonetheless, the clinical judgment of physicians remains extremely important; hence, when using these best clinical practices to inform treatment options and decisions, practitioners should also consider the individual circumstances of their patients on a case-by-case basis.

Trastuzumab cardiotoxicity: from clinical trials to experimental studies

Epidermal growth factor receptor-2 (HER-2) is overexpressed in 20 to 25% of human breast cancers, which is associated with aggressive tumour growth and poor prognosis. Trastuzumab (Herceptin®) is a humanized monoclonal antibody directed against HER-2, the first highly selective form of therapy targeting HER-2 overexpressing tumours. Although initial trials indicated high efficacy and a favourable safety profile of the drug, the first large, randomized trial prompted a retrospective analysis of cardiac dysfunction in earlier trials utilizing trastuzumab. There has been ongoing debate on the cardiac safety of trastuzumab ever since, initiating numerous clinical and preclinical investigations to better understand the background of trastuzumab cardiotoxicity and evaluate its effects on patient morbidity. Here, we have given a comprehensive overview of our current knowledge on the cardiotoxicity of trastuzumab, primarily focusing on data from clinical trials and highlighting the main molecular mechanisms proposed.

LINKED ARTICLES

This article is part of a themed section on New Insights into Cardiotoxicity Caused by Chemotherapeutic Agents. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.21/issuetoc.

Efficacy and safety of neoadjuvant chemotherapy with concurrent liposomal-encapsulated doxorubicin, paclitaxel and trastuzumab for human epidermal growth factor receptor 2-positive breast cancer in clinical practice

BACKGROUND

Based on previous results obtained with non-pegylated liposomal-encapsulated doxorubicin (TLC-D99) together with paclitaxel and trastuzumab in patients with human epidermal growth factor receptor 2 (HER2)-positive locally advanced or metastatic breast cancer (BC), a similar regimen was evaluated in the neoadjuvant setting in a prospectively selected series of consecutive patients with clinical stage II-III BC. Primary and secondary objectives included the rate of pathologic complete response (pCR), safety, and predictive factors of pCR.

METHODS

Patients received six cycles of TLC-D99 (50 mg/m(2) every 3 weeks), paclitaxel (80 mg/m(2) weekly) and trastuzumab (4 mg/kg initial dose and 2 mg/kg weekly). All patients underwent surgery after treatment. pCR was defined as the absence of invasive cancer cells in the breast and the axilla.

RESULTS

Sixty-two patients with a median age of 46.6 years were analyzed. Stage IIIA was diagnosed in 43.5% of patients and 14.5% had inflammatory BC. Conservative surgery was performed in 46.8% of the patients and pCR was achieved in 63% (95% CI 50.5-75.5). Patients with estrogen receptor (ER)-negative tumors presented a significantly higher pCR rate than patients with ER-positive tumors (74.4 vs 43.5%; P = 0.028). Forty-five patients (72.6%) completed study treatment and 80.6% received at least five treatment cycles. No patients developed congestive heart failure and 14.5% of patients showed a ≥ 10 % decrease in the left ventricular ejection fraction.

CONCLUSION

The triple combination therapy assessed is effective and safe, offering a high pCR rate in patients with HER2-positive BC.

Liposomal Doxorubicin in the treatment of breast cancer patients: a review

Drug delivery systems can provide enhanced efficacy and/or reduced toxicity for anticancer agents. Liposome drug delivery systems are able to modify the pharmacokinetics and biodistribution of cytostatic agents, increasing the concentration of the drug released to neoplastic tissue and reducing the exposure of normal tissue. Anthracyclines are a key drug in the treatment of both metastatic and early breast cancer, but one of their major limitations is cardiotoxicity. One of the strategies designed to minimize this side effect is liposome encapsulation. Liposomal anthracyclines have achieved highly efficient drug encapsulation and they have proven to be effective and with reduced cardiotoxicity, as a single agent or in combination with other drugs for the treatment of either anthracyclines-treated or naïve metastatic breast cancer patients. Of particular interest is the use of the combination of liposomal anthracyclines and trastuzumab in patients with HER2-overexpressing breast cancer. In this paper, we discuss the different studies on liposomal doxorubicin in metastatic and early breast cancer therapy.

Echocardiography signs of early cardiac impairment in patients with breast cancer and trastuzumab therapy

OBJECTIVE

Recent studies in breast cancer patients and Trastuzumab therapy (Herceptin) showed a development of a toxic cardiomyopathy as a severe complication. The aim of this study was to discover early changes in cardiac function and morphology.

METHODS

We studied 42 female patients with Her-2/-neu over-expression in breast cancer by echocardiography before, 3, and 6 months after start of the adjuvant Herceptin therapy. All values were mean value ± standard deviation.

RESULTS

After 3 or 6 months of a trastuzumab therapy we discovered significant increases in the diastolic and systolic left ventricle volume indices (LV-DVI 32.4 ± 8.5 vs. 38.5 ± 8.7 vs. 40.3 ± 10.3 ml/m², p < 0.001 and LV-SVI 12.6 ± 4.0 vs. 15.7 ± 4.7 vs. 17.2 ± 6.8 ml/m², p < 0.001), an increase of the end-diastolic and end-systolic LV diameter (LVEDD 46.8 ± 4.2 vs. 48.0 ± 4.7 vs. 49.7 ± 4.5 ml/m², p < 0.01; LVESD 28.3 ± 4.2 vs. 31.0 ± 4.7 vs. 32.3 ± 4.9 mm, p < 0.001), a reduced systolic ventricle function determined by the tissue Doppler imaging (TDI) velocity (9.2 ± 2.5 vs. 8.0 ± 1,7 vs. 7.7 ± 1.5 cm/s, p < 0.001), fractional shortening (39,6 ± 7.5 vs. 35.4 ± 7.4 vs. 35.2 ± 7.0%, p < 0.01), and the LV-EF Simpson biplane [62.0 ± 5.1 vs. 60.1 ± 6.3 (p = ns) vs. 58.4 ± 7.9%, p < 0.01] compared to pretreatment values. There was also an increase of the left atrial volume index (21.4 ± 6.2 vs. 26.2 ± 7.9 vs. 29.7 ± 8.8 ml/m², p < 0.001), a decrease of the median TDI atrial velocities (11.9 ± 2.4 vs. 10.5 ± 2.8 vs. 10.1 ± 2.1 cm/s, p < 0.01), an increase of the peak early diastolic filling velocities (73.1 ± 15.4 vs. 83.1 ± 16.4 vs. 82.2 ± 19.4 cm/s, p < 0.05), and an increase of the median mitral valve insufficiency degree (0.64 ± 0.65 vs. 1.03 ± 0.76 vs. 1.11 ± 0.73°, p < 0.001). We could not detect a significant increase in diastolic dysfunction. Also right heart diameters and function did not change significantly. Most patients stayed in an asymptomatic stage of cardiac disease.

CONCLUSION

The blockade of Her2/-neu receptors with trastuzumab in patients with breast cancer led to measurable alterations of left ventricular volume, left atrial volume, and systolic function as early as 3 months after start of treatment.

Anthracycline cardiotoxicity

INTRODUCTION

Anthracyclines are widely prescribed anticancer agents that cause a dose-related cardiotoxicity, often aggravated by nonanthracycline chemotherapeutics or new generation targeted drugs. Anthracycline cardiotoxicity may occur anytime in the life of cancer survivors. Understanding the molecular mechanisms and clinical correlates of cardiotoxicity is necessary to improve the therapeutic index of anthracyclines or to identify active, but less cardiotoxic analogs.

AREAS COVERED

The authors review the pharmacokinetic, pharmacodynamic and biochemical mechanisms of anthracycline cardiotoxicity and correlate them to clinical phenotypes of cardiac dysfunction. Attention is paid to bioactivation mechanisms that converted anthracyclines to reactive oxygen species (ROS) or long-lived secondary alcohol metabolites. Preclinical aspects and clinical implications of the "oxidative stress" or "secondary alcohol metabolite" hypotheses are discussed on the basis of literature that cuts across bench and evidence-based medicine. Interactions of anthracyclines with comorbidities or unfavorable lifestyle choices were identified as important cofactors of the lifetime risk of cardiotoxicity and as possible targets of preventative strategies.

EXPERT OPINION

Anthracycline cardiotoxicity is a multifactorial process that needs to be incorporated in a translational framework, where individual genetic background, comorbidities, lifestyles and other drugs play an equally important role. Fears for cardiotoxicity should not discourage from using anthracyclines in many oncologic settings. Cardioprotective strategies are available and should be used more pragmatically in routine clinical practice.

Predicting environmental chemical factors associated with disease-related gene expression data

BACKGROUND

Many common diseases arise from an interaction between environmental and genetic factors. Our knowledge regarding environment and gene interactions is growing, but frameworks to build an association between gene-environment interactions and disease using preexisting, publicly available data has been lacking. Integrating freely-available environment-gene interaction and disease phenotype data would allow hypothesis generation for potential environmental associations to disease.

METHODS

We integrated publicly available disease-specific gene expression microarray data and curated chemical-gene interaction data to systematically predict environmental chemicals associated with disease. We derived chemical-gene signatures for 1,338 chemical/environmental chemicals from the Comparative Toxicogenomics Database (CTD). We associated these chemical-gene signatures with differentially expressed genes from datasets found in the Gene Expression Omnibus (GEO) through an enrichment test.

RESULTS

We were able to verify our analytic method by accurately identifying chemicals applied to samples and cell lines. Furthermore, we were able to predict known and novel environmental associations with prostate, lung, and breast cancers, such as estradiol and bisphenol A.

CONCLUSIONS

We have developed a scalable and statistical method to identify possible environmental associations with disease using publicly available data and have validated some of the associations in the literature.

First-Line Trastuzumab Plus Epirubicin and Cyclophosphamide Therapy in Patients With Human Epidermal Growth Factor Receptor 2–Positive Metastatic Breast Cancer: Cardiac Safety and Efficacy Data From the Herceptin, Cyclophosphamide, and Epirubicin (HERCULES) Trial

Purpose

A high incidence of congestive heart failure (CHF) has been observed in patients with metastatic breast cancer (MBC) receiving doxorubicin-based chemotherapy and trastuzumab. The Herceptin, Cyclophosphamide, and Epirubicin (HERCULES) trial evaluated trastuzumab plus cyclophosphamide and the less cardiotoxic anthracycline epirubicin.

Patients and Methods

This prospective trial combined a phase I dose-finding stage with a phase II randomized stage. In total, 120 patients with human epidermal growth factor receptor 2 (HER2) –positive MBC and adequate cardiac function received first-line trastuzumab (4 mg/kg intravenous loading dose, then 2 mg/kg every week) plus cyclophosphamide (600 mg/m2) and either epirubicin 60 mg/m2 (HEC-60) or 90 mg/m2 (HEC-90) for six cycles, followed by trastuzumab monotherapy until progression. Sixty patients with HER2-negative disease received epirubicin (90 mg/m2) and cyclophosphamide (EC-90) alone. The primary end point was dose-limiting cardiotoxicity (DLC).

Results

Incidence of DLC was 5.0%, 1.7%, and 0% in the HEC-90, HEC-60, and EC-90 arms, respectively. All DLC events were manageable. There were no cardiac-related deaths. Other adverse-event profiles were comparable across the three arms, except febrile neutropenia, which was reported in 10% of the HEC-90 arm compared with 3% of the other arms. Tumor response rates were 57%, 60%, and 25% in the HEC-60, HEC-90, and EC-90 arms, respectively; median time to progression was 12.5, 10.1, and 7.6 months, respectively.

Conclusion

The HEC regimen is a promising treatment option for patients with HER2-positive MBC. The lower incidence of DLC with HEC, compared with the historic incidence associated with trastuzumab plus doxorubicin, supports further evaluation of the regimen, especially in adjuvant or neoadjuvant settings.

A multicentre Phase II study of non-pegylated liposomal doxorubicin in combination with trastuzumab and docetaxel as first-line therapy in metastatic breast cancer

To evaluate the cardiotoxicity, general toxicity, and activity of non-pegylated liposomal doxorubicin, in combination with docetaxel and trastuzumab, as first-line therapy in metastatic breast cancer. Thirty-one patients with metastatic human epidermal growth factor receptor 2-overexpressing breast cancer, who had not previously received chemotherapy for metastatic disease, received non-pegylated liposomal doxorubicin (50 mg/m(2)), docetaxel (75 mg/m(2)) and trastuzumab (2 mg/kg/week) for up to eight cycles, followed by trastuzumab alone for up to 52 weeks. Cardiotoxicity was defined as a decrease in left ventricular ejection fraction (LVEF) to below 45%, or a decrease in LVEF of at least 20% from baseline. Mean LVEF was maintained at baseline level also in the subset of patients who had received anthracycline previously. Cardiotoxicity developed in three patients during the treatment cycles, and in two further patients after the end of the study. The most common adverse events were haematological toxicity, alopecia, asthenia and fever. The best overall response rate was 65.5%. Median time to progression was 13.0 months. The combination of non-pegylated liposomal doxorubicin, docetaxel and trastuzumab combines acceptable cardiac and general toxicity and promising activity as first-line therapy in metastatic breast cancer.

Immunological Approaches in the Treatment of Metastasized Breast Cancer

A better understanding of tumor biology has led to the development of a number of antibody-based targeted therapies in breast cancer. Several of these newer agents, such as trastuzumab and bevacizumab have demonstrated clinical activity and have improved the treatment of patients with metastatic breast cancer (MBC). Trastuzumab is a monoclonal antibody that binds to the extracellular domain of the HER2 receptor. The addition of trastuzumab to chemotherapy and also to endocrine therapy has enhanced efficacy of treatment. New antibody-based strategies directed against HER2 are under development. These new approaches include pertuzumab, an antibody with a different binding epitope that inhibits dimerization of HER2 with other members of the HER receptor family and TDM1, a trastuzumab-based antibody chemotherapeutic conjugate. Another approach to the treatment of solid tumors is inhibition of angiogenesis. The anti-VEGF antibody bevacizumab has been approved for treatment of MBC. Although the mechanism of action is still under investigation, bevacizumab is tested in other clinical settings such as adjuvant therapy, maintenance therapy, and in combination with both chemotherapy and other targeted agents. In this review, we will summarize the most important studies on trastuzumab and bevacizumab, and describe new antibodies currently under clinical development.

HER-2-positive metastatic breast cancer: trastuzumab and beyond

BACKGROUND

The recognition achieved in the late 1980s of human epidermal growth factor receptor 2 as an appealing therapeutic target for breast cancer has led to the development of targeted therapies for patients with human epidermal growth factor receptor 2-overexpressing breast tumors.

OBJECTIVES

The aim of the present review is to address the standard treatment of human epidermal growth factor receptor 2-positive metastatic breast cancer patients, which is currently based on the humanized monoclonal antibody trastuzumab and to describe the new treatment options available for patients progressing on trastuzumab-based therapies.

METHODS

A broad literature research was performed in order to review treatments, starting from the developmental phase of trastuzumab to the most recent biologic agents being tested in human epidermal growth factor receptor 2-positive disease.

RESULTS

Trastuzumab combined with a taxane represents the first therapeutic option for human epidermal growth factor receptor 2-positive metastatic breast cancer. However, novel combinations of trastuzumab and chemotherapy still hold great interest for their remarkable activity and good tolerability. On the other hand, the dual epidermal growth factor receptor/human epidermal growth factor receptor 2 inhibitor lapatinib has been the first drug to be approved in combination with capecitabine for the treatment of patients who progress on trastuzumab-based therapies. Moreover, in the near future, trastuzumab plus another biologic agent targeting human epidermal growth factor receptor 2, either directly or indirectly, may represent an effective 'chemotherapy-free' combination for trastuzumab-refractory patients.

Cardiotoxicity of antitumor drugs

Many antitumor drugs cause "on treatment" cardiotoxicity or introduce a measurable risk of delayed cardiovascular events. Doxorubicin and other anthracyclines cause congestive heart failure that develops in a dose-dependent manner and reflects the formation of toxic drug metabolites in the heart. Cardiovascular events may occur also with other chemotherapeutics, but the dose or metabolism dependence of such events are less obvious and predictable. Drugs targeted to tumor-specific receptors or metabolic routes were hoped to offer a therapeutic gain while also sparing the heart and other healthy tissues; nonetheless, many such drugs still cause moderate to severe cardiotoxicity. Targeted drugs may also engage a cardiotoxic synergism with "old-fashioned" chemotherapeutics, as shown by the higher than expected incidence of anthracycline-related congestive heart failure that occurred in patients treated with doxorubicin and the anti HER2 antibody Trastuzumab. Mechanism-based considerations and retrospective analyses of clinical trials now form the basis for a new classification of cardiotoxicity, type I for anthracyclines vs type II for Trastuzumab. Such a classification may serve a template to accommodate other paradigms of cardiotoxicity induced by new drugs and combination therapies. Of note, laboratory animal models did not always anticipate the mechanisms and/or metabolic determinants of cardiotoxicity induced by antitumor drugs or combination therapies. Toxicologists and regulatory agencies and clinicians should therefore join in collaborative efforts that improve the early identification of cardiotoxicity and minimize the risks of cardiac events in patients.

Oral vinorelbine: role in the management of metastatic breast cancer

The treatment of advanced breast cancer is continually evolving, with the aim of improving the quality and duration of remission and, in some instances, survival. In this setting, the importance of quality of life cannot be underestimated, and growing attention is being paid to treatment convenience and compliance. New anticancer agents have improved efficacy, but for many of them, toxicity often remains a problem. Vinorelbine seems to represent both an active and a well tolerated treatment for metastatic breast cancer. In particular, the oral formulation has similar efficacy to that of the injectable formulation and has demonstrated generally favourable tolerability, with a high degree of acceptance by both patients and physicians. The availability of this and other novel, well tolerated and effective treatments provides greater potential to tailor treatment to meet individual patient needs and, therefore, also provide the potential to improve patient outcomes. Preliminary data suggest that oral vinorelbine may permit continued, effective chemotherapy when further parenteral therapy with more intensive and more toxic agents is considered inappropriate. Early findings also suggest that oral vinorelbine, when administered together with another new oral agent, capecitabine, may be a valid choice in metastatic breast cancer treatment. Furthermore, vinorelbine plus the monoclonal antibody trastuzumab, with or without oral capecitabine, appears to be another regimen that may be worthy of additional study in patients with human epidermal growth factor-2 positive advanced breast cancer.

A review of the use of trastuzumab (Herceptin®) plus vinorelbine in metastatic breast cancer

The combination of trastuzumab (Herceptin) and vinorelbine (Navelbine) in the treatment of human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) is valuable for several reasons. There is proven synergism of these agents in preclinical models, both agents are well tolerated and there is minimal overlapping toxicity. This article reviews clinical experience with trastuzumab and vinorelbine from phase II/III trials including >450 assessable patients. Results across the trials show objective response rates for the combination in the range of 44%-86% (51%-86% as first-line treatment) and a median duration of response of 10-17.5 months. Approximately 50% of patients experience grade 3/4 neutropenia, which is of short duration and manageable. Symptomatic cardiac events are infrequent (seven episodes of grade 3 toxicity across all trials). Overall, trastuzumab-vinorelbine combination therapy offers patients with HER2-positive MBC, an effective and well-tolerated treatment that is suitable for prolonged duration of use.

Safety and activity of trastuzumab-containing therapies for the treatment of metastatic breast cancer: our long-term clinical experience (GOIM study)

BACKGROUND

Trastuzumab is widely used as the treatment of choice for HER2-positive metastatic breast cancer (MBC).

PATIENTS AND METHODS

Seventy patients, median age 57 years and range 31-81 years, were included in our retrospective analysis with the aim to evaluate safety and activity of trastuzumab-containing therapies.

RESULTS

We observed for first-line treatment response rate (RR) 41%, stable disease (SD) 47% and time to progression (TTP) 8 months (range 1-44). Corresponding numbers for second line were RR 23%, SD 62% and (TTP) 9 months (range 3-23) and beyond second line RR 22%, SD 78% and (TTP) 9 months (range 4-19). Overall survival was 19.2 months (3-62 months). The median cumulative dose of trastuzumab administrated was 5286 mg (464-17 940 mg). Trastuzumab was well tolerated. Median left ventricular ejection function (LVEF) at baseline was 62% and at the end of treatment was 59%. The more relevant adverse events consisted of an asymptomatic decrease in LVEF to 40% (baseline 60%) and a grade 3 symptomatic increase in bilirubin.

CONCLUSION

Trastuzumab-containing therapies in MBC show a good safety and toxicity profile and a remarkable activity even in heavily pretreated women. Patients should benefit from continued trastuzumab therapy, as shown by the maintenance of (TTP) even beyond second-line treatment.

Monoclonal antibody-based targeted therapy in breast cancer: current status and future directions

The recent development of monoclonal antibodies targeting growth factor receptors in cancer treatment represents a milestone for both researchers and physicians. Advances in the understanding of key molecular pathways for tumour growth and survival have facilitated the development of these targeted therapies, in particular in breast cancer. This review focuses on the three most important recombinant humanised monoclonal antibodies that have shown activity in women with breast cancer: trastuzumab, pertuzumab and bevacizumab. Trastuzumab, an anti-erbB2 (human epidermal growth factor receptor) monoclonal antibody, is currently routinely used in both the metastatic and adjuvant settings for patients with erbB2-positive tumours. Pertuzumab, a monoclonal antibody binding to a different epitope on erbB2 than trastuzumab, is under early clinical evaluation. This drug has been developed for breast cancer patients, whether overexpressing erbB2 or not. Bevacizumab, a monoclonal antibody directed against vascular endothelial growth factor-A, is being evaluated in the metastatic setting for its antiangiogenic properties, and is showing promising results.

HER‐2‐Positive Metastatic Breast Cancer: Optimizing Trastuzumab‐Based Therapy

Trastuzumab with a taxane as first-line therapy is now the standard of care for patients with human epidermal growth factor receptor 2 (HER-2)-positive metastatic breast cancer (MBC). The search for additional and more effective trastuzumab-based therapies continues. Novel combinations of trastuzumab with chemotherapeutic agents, including vinorelbine, gemcitabine, and capecitabine, and hormonal therapy agents, such as tamoxifen and aromatase inhibitors, are currently under investigation in clinical trials. Available data suggest these combinations will provide additional treatment options that may ultimately lead to better outcomes for patients with HER-2-positive MBC. Evidence is growing for the use of trastuzumab treatment beyond disease progression and retreatment after (neo)adjuvant relapse is being explored to assist in clinical decision making. Already, the use of trastuzumab in the metastatic setting has changed HER-2-positive status from a marker of poor prognosis to one of better overall outcome, and ongoing studies should expand further the treatment options for patients with HER-2-positive MBC.

Adjuvant docetaxel or vinorelbine with or without trastuzumab for breast cancer

BACKGROUND

We compared docetaxel with vinorelbine for the adjuvant treatment of early breast cancer. Women with tumors that overexpressed HER2/neu were also assigned to receive concomitant treatment with trastuzumab or no such treatment.

METHODS

We randomly assigned 1010 women with axillary-node-positive or high-risk node-negative cancer to receive three cycles of docetaxel or vinorelbine, followed by (in both groups) three cycles of fluorouracil, epirubicin, and cyclophosphamide. The 232 women whose tumors had an amplified HER2/neu gene were further assigned to receive or not to receive nine weekly trastuzumab infusions. The primary end point was recurrence-free survival.

RESULTS

Recurrence-free survival at three years was better with docetaxel than with vinorelbine (91 percent vs. 86 percent; hazard ratio for recurrence or death, 0.58; 95 percent confidence interval, 0.40 to 0.85; P=0.005), but overall survival did not differ between the groups (P=0.15). Within the subgroup of patients who had HER2/neu-positive cancer, those who received trastuzumab had better three-year recurrence-free survival than those who did not receive the antibody (89 percent vs. 78 percent; hazard ratio for recurrence or death, 0.42; 95 percent confidence interval, 0.21 to 0.83; P=0.01). Docetaxel was associated with more adverse effects than was vinorelbine. Trastuzumab was not associated with decreased left ventricular ejection fraction or cardiac failure.

CONCLUSIONS

Adjuvant treatment with docetaxel, as compared with vinorelbine, improves recurrence-free survival in women with early breast cancer. A short course of trastuzumab administered concomitantly with docetaxel or vinorelbine is effective in women with breast cancer who have an amplified HER2/neu gene. (International Standard Randomised Controlled Trial number, ISRCTN76560285.).

Multicenter phase II study of trastuzumab in combination with epirubicin and docetaxel as first-line treatment for HER2-overexpressing metastatic breast cancer

The primary objective of study is to evaluate cardiac safety of trastuzumab in combination with epirubicin and docetaxel. HER2-overexpressing metastatic breast cancer patients were enrolled in a two-stage, multicenter phase II trial with weekly trastuzumab (4 and then 2 mg/kg) with epirubicin and docetaxel (either 75 mg/m(2)) on day 1 every 3 weeks. After eight courses of chemotherapy, trastuzumab was continued as a single agent. To assess cardiotoxicity, patients were evaluated for left ventricular ejection fraction (LVEF) at baseline, every two cycles during chemotherapy and trastuzumab, and every 3 months during trastuzumab alone. Cardiotoxicity was defined as signs and/or symptoms of congestive heart failure (CHF) and/or an absolute decrease in LVEF of >or=20 units or a decline to <or=45%. In the first stage of the study, three episodes of cardiotoxicity were observed (two asymptomatic declines of LVEF and one CHF) in 29 patients, and recruitment continued. During follow-up of patients who continued trastuzumab after chemotherapy, seven further cardiologic events occurred (three asymptomatic decline of LVEF and four CHF). Therefore, recruitment was interrupted after the 45th patient. The majority of cardiac events occurred late during trastuzumab alone, half were asymptomatic and all cases of CHF were resolved using cardiac therapy. Complete and partial responses were 20 and 47%, respectively, and the median time to progression was 15.7 months (95% CI, 11.6-19.0 months). In light of the cardiotoxicity experienced during this study, we currently recommend that this combination be used only in controlled clinical trials under vigilant cardiac monitoring.

Adjuvant Chemotherapy for Early Breast Cancer: Optimal Use of Epirubicin

Anthracyclines are central components of adjuvant combination chemotherapy regimens for early breast cancer. Epirubicin is underutilized for this indication in the United States, where it was approved by the Food and Drug Administration in 1999, compared to Europe and Canada, where it gained approval in 1980. Use of epirubicin offers advantages in specific treatment settings and patient subsets, including situations where use of dose-dense and/or dose-intense protocols may provide additional benefits and where combinations including taxanes and/or trastuzumab may provide increased efficacy. Epirubicin also has a distinct safety profile compared to doxorubicin with regard to cardiotoxicity. In order to optimize treatment benefits and safety concerns for node-positive, node-negative and HER-2-positive patients as well as patients receiving neoadjuvant therapy and elderly patients it is worthwhile to consider the potential benefits of epirubicin.

Pegylated liposomal doxorubicin in combination with gemcitabine: a phase II study in anthracycline-naïve and anthracycline pretreated metastatic breast cancer patients

BACKGROUND

The aim of the study was to assess the toxicity profile, activity in terms of response rate, time to progression, overall survival, and quality of life of pegylated liposomal doxorubicin (PLD) and gemcitabine combination in chemo-naïve and pretreated metastatic breast cancer (MBC) women.

METHODS

Patients were eligible if they had disease progression to prior chemotherapy (anthracycline-including or not) for early breast cancer or MBC. Patients received PLD 25 mg/m(2) intravenously on day 1 plus gemcitabine 800 mg/m(2) intravenously on days 1 and 8 of each 21-day cycle.

RESULTS

Of 50 patients enrolled, 37 had received prior adjuvant chemotherapy (24 with an anthracycline) and 23 prior chemotherapy for metastatic disease (6 with an anthracycline). Two complete responses and 20 partial responses were achieved in 46 assessable patients (overall response rate: 47.8%). Responses were observed in 14 (46.6%) of 30 patients with previous anthracycline exposure. Median response duration was 7 months, median duration of clinical benefit 8 months, time to progression 7 months. At a median follow-up of 10 months, 79.4% patients were alive at 1 year. No neutropenic complication was observed. Non-hematological toxicities were mild. One patient previously treated with an anthracycline developed a transient decrease (26%) in the left ventricular ejection fraction, with cardiac function recovering within 6 months.

CONCLUSION

Because of the non-overlapping toxicity profiles of both PLD and gemcitabine, this combination can be regarded as a reliable therapeutic option for patients who have failed previous treatments, including anthracycline, for MBC.

Therapeutic Index by Combination of Adriamycin and Docetaxel Depends on Dosing Time in Mice

Although the combination of adriamycin and docetaxel showed a better cure rate against metastatic breast cancer, severe myelosuppression and cardiotoxicity were dose-limiting factors. The purpose of this study was to establish a suitable dosing schedule, based on a chronopharmacologic approach, to relieve severe adverse effects. In experiment 1, adriamycin or docetaxel was injected i.p. at 2, 6, 10, 14, 18, or 22 hours after light onset (HALO) to estimate toxicities. In experiment 2, the dosing time dependency of toxicity and pharmacokinetics were assessed in the combination of adriamycin and docetaxel. In addition, G2-M phase in myelocyte cells was determined in nontreated mice. Adverse effects caused by adriamycin were shown to be the worst at 2 HALO and the best at 14 HALO. On the other hand, docetaxel-induced adverse effects were more severe at 14 HALO than at 2 HALO. In the combination study, the D(2)-A(1)4 group, in which docetaxel was administered at 2 HALO followed by adriamycin at 14 HALO, showed the most toxicity relief of all the treated groups. In the pharmacokinetic study, the dosing time dependency of toxicities was not related to the daily variation of pharmacokinetics of adriamycin and docetaxel. A significant 24-hour rhythm of G2-M phase distribution was found in myelocyte cells of nontreated mice. The daily variation of leukopenia caused by docetaxel corresponded to the 24-hour rhythm of G2-M phase distribution. These findings reveal that the therapeutic index of the combined chemotherapy can be improved by administering adriamycin and docetaxel at the time when the most adverse effects are relieved in each drug.

Targeting HER2 as a therapeutic strategy for breast cancer: a paradigmatic shift of drug development in oncology

Targeted therapies are causing a dramatic change in cancer drug development. Trastuzumab, a humanized recombinant monoclonal antibody that recognizes the extracellular domain of HER2 trans-membrane protein, is among the first target-specific drugs that have been licensed for clinical use and its development represents a model of integration of new agents with classical treatment strategies. In preclinical models, trastuzumab has demonstrated a marked antiproliferative effect and a synergistic action with several chemotherapeutic agents. Monotherapy trials indicate that trastuzumab is active as a single agent in HER2 positive patients, is well tolerated, and is associated with preservation of quality of life (QoL). Furthermore, as first line therapy for metastatic breast cancer overexpressing HER2 receptor, the addition of trastuzumab to taxane-based chemotherapy significantly increased rate of objective response, time to disease progression and survival when compared with chemotherapy alone. Trastuzumab has shown important activity when used with many chemotherapeutic agents such as platinum salts, gemcitabine, vinorelbine and capecitabine and liposomal anthracyclines. Various trials are now ongoing to optimize the use of trastuzumab and to investigate its role in the adjuvant and in the neo-adjuvant setting.

Optimizing treatment of HER2-positive metastatic breast cancer

The primary goal of therapy for metastatic breast cancer is to improve the outcome for patients. Ideally, this should be achieved with minimal short-term side effects and without long-term irreversible toxicity. Trastuzumab (Herceptin; F. Hoffmann-La Roche, Basel, Switzerland) is proven to be efficacious in women with metastatic breast cancer who have HER2-positive disease. Data from pivotal clinical trials and postmarketing surveillance in women with metastatic breast cancer confirm that trastuzumab is also well tolerated with a low incidence of conventional chemotherapeutic side effects. Severe adverse events are confined to serious infusion-related reactions and cardiac issues, which are infrequent and readily managed. Patients at risk of these severe events can be identified before starting trastuzumab therapy. Ideally, treatment should also be convenient for the patient. This can be achieved through less frequent dosing. A 3-weekly trastuzumab schedule, with higher individual loading and maintenance doses than the conventional weekly schedule, has been investigated. This has similar efficacy, tolerability, and pharmacokinetics (exposure) to the weekly regimen, providing a convenient schedule.

Maximizing clinical benefit with trastuzumab

To optimize patient management in breast cancer a number of factors are considered, including hormone receptor and HER2 status. A feasible approach for women with less aggressive, estrogen receptor/HER2-positive metastatic breast cancer is to consider trastuzumab (Herceptin; F. Hoffmann-La Roche, Basel, Switzerland) combined with endocrine therapy. Randomized clinical trials are ongoing to assess the combination of trastuzumab with aromatase inhibitors. In patients with aggressive HER2-positive metastatic breast cancer, trastuzumab/chemotherapy combination regimens are warranted. When administered first line in combination with a taxane, trastuzumab improves all clinical outcome parameters, including survival, in such patients. Trastuzumab adds little to the toxicity profile of taxanes, and trastuzumab combination therapy is associated with improvements in quality of life when compared with chemotherapy alone. There is encouraging evidence of improved efficacy when trastuzumab is combined with other cytotoxic agents with proven single-agent activity in breast cancer, including capecitabine (Xeloda; F. Hoffmann-La Roche), gemcitabine, and vinorelbine. Trastuzumab is also being investigated as part of triplet drug regimens. Trastuzumab has good single-agent activity in first-line therapy. This is of relevance to women with HER2-positive disease who are not suitable for, or do not wish to receive, cytotoxic chemotherapy. The benefits noted with trastuzumab-containing regimens were documented in clinical trials where trastuzumab was given until disease progression. A further rationale exists to continue trastuzumab beyond progression. Data from retrospective reviews indicate that this strategy is feasible.