Trastuzumab and gemcitabine as salvage therapy in heavily pre-treated patients with metastatic breast cancer

Oral Etoposide and Trastuzumab Use for HER2-Positive Metastatic Breast Cancer: A Retrospective Study from the Institut Curie Hospitals

BACKGROUND

The TOP2A and ERBB2 genes are co-amplified in about 40% of HER2 positive (HER2+) breast cancers. Oral etoposide (VP16), an inhibitor of topoisomerase-II (encoded by TOP2A), has demonstrated clinical activity in metastatic breast cancer (MBC). The benefit of oral VP16 combined with trastuzumab (VP16-T) in HER2+ MBC has not yet been evaluated.

METHODS

Patients treated at the Institut Curie Hospitals with VP16-T for HER2+ MBC were retrieved by an in silico search. Progression-free survival (PFS), overall survival (OS), response rate, prolonged PFS (defined as at least 6 months), clinical benefit, and toxicity were assessed. The co-amplification of ERBB2 and TOP2A was assessed by shallow whole genome sequencing on tumor tissue whenever available.

RESULTS

Forty-three patients received VP16-T after a median number of six prior treatment lines for HER2+ MBC. Median PFS and OS were 2.9 months (95% CI [2.4-4.7]) and 11.3 months (95% CI [8.3-25.0]), respectively. Three patients had a complete response, while 12/40 (30%) experienced clinical benefit. Only three patients stopped treatment for toxicity. Seven (35%) patients displayed a TOP2A/ERBB2 co-amplification. No statistically significant correlation was found between outcome and TOP2A/ERBB2 co-amplification.

CONCLUSION

Our analysis suggests a favorable efficacy and toxicity profile for VP16-T in patients with heavily pretreated HER2+ MBC.

Incidence of central nervous system metastases in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer treated with trastuzumab: A meta-analysis

This study aimed to estimate the incidence of central nervous system (CNS) metastases in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) treated with trastuzumab. Studies were identified through a literature search of electronic databases. Random-effects meta-analyses were performed to estimate the incidence rate of CNS metastases, trastuzumab therapy duration, and time from trastuzumab therapy to CNS metastasis diagnosis. A meta-analysis of odds ratios was performed to evaluate the significance of a difference in CNS metastasis incidence between patients with and without trastuzumab treatment. Thirty studies (8121 trastuzumab-treated and 3972 control patients) were included. The follow-up duration was 18.9 months (95% confidence interval [CI]: 13.8, 24.1). The trastuzumab treatment duration was 9.0 months (95% CI: 7.0, 11.0). The median interval between the start of trastuzumab therapy and CNS metastasis diagnosis was 12.2 months (95% CI: 9.5, 14.7). The incidence of CNS metastasis after the start of trastuzumab therapy was 22% (95% CI: 16, 27). The incidence of CNS metastases was significantly higher in trastuzumab-treated than in non-trastuzumab-treated patients (odds ratio: 1.39 [95% CI: 1.06, 1.82], p=0.02). The survival time from the start of the study was 23.4 months (95% CI: 19.7, 27.1) in trastuzumab-treated patients and 18.4 months (95% CI: 12.7, 24.1) in patients treated with control regimens. The survival time after the development of CNS metastases in trastuzumab-treated patients was 19.2 months (95% CI: 15.6, 25.9). Approximately 22% of patients with HER2-positive MBC who were treated with trastuzumab developed CNS metastases. However, trastuzumab-treated patients had a longer survival than patients who were not treated with trastuzumab.

HER2-targeted therapy prolongs survival in patients with HER2-positive breast cancer and intracranial metastatic disease: a systematic review and meta-analysis

BACKGROUND

Intracranial metastatic disease (IMD) is a serious and known complication of human epidermal growth factor receptor 2 (HER2)-positive breast cancer. The role of targeted therapy for patients with HER2-positive breast cancer and IMD remains unclear. In this study, we sought to evaluate the effect of HER2-targeted therapy on IMD from HER2-positive breast cancer.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, and gray literature sources for interventional and observational studies reporting survival, response, and safety outcomes for patients with IMD receiving HER2-targeted therapy. We pooled outcomes through meta-analysis and examined confounder effects through forest plot stratification and meta-regression. Evidence quality was evaluated using GRADE (PROSPERO CRD42020161209).

RESULTS

A total of 97 studies (37 interventional and 60 observational) were included. HER2-targeted therapy was associated with prolonged overall survival (hazard ratio [HR] 0.47; 95% confidence interval [CI], 0.39-0.56) without significantly prolonged progression-free survival (HR 0.52; 95% CI, 0.27-1.02) versus non-targeted therapy; the intracranial objective response rate was 19% (95% CI, 12-27%), intracranial disease control rate 62% (95% CI, 55-69%), intracranial complete response rate 0% (95% CI, 0-0.01%), and grade 3+ adverse event rate 26% (95% CI, 11-45%). Risk of bias was high in 40% (39/97) of studies.

CONCLUSION

These findings support a potential role for systemic HER2-targeted therapy in the treatment of patients with IMD from HER2-positive metastatic breast cancer.

Use of Trastuzumab in HER2-positive Metastatic Breast Cancer beyond Disease Progression: A Systematic Review of Published Studies

Aims and background

Trastuzumab, a humanized monoclonal antibody directed against the extracellular domain of ErbB, has determined clinical benefit for women affected by metastatic or early stage HER2-positive breast cancer and never previously treated with trastuzumab. Trastuzumab is generally used as first-line treatment of HER2+ metastatic breast cancer and is currently administered beyond progression even without clear evidence supporting such clinical practice. In fact, HER2-positive metastatic breast cancer has a high risk of progressing after first-line therapy, and second-line treatments vary. The aim of the study was to investigate by a systematic review the efficacy of trastuzumab-based treatments beyond progression in HER2-positive metastatic breast cancer.

Materials and methods

We performed a systematic review using Medline, Embase and Cochrane Library data bases and publications in principal meetings or congresses of oncology in Europe and America until September 2008. The main selection criterium was the reporting of time to progression, calculated from the start of each trastuzumab-based therapy to the date of progressive disease or death.

Results

Twelve studies were selected that included a total of 516 patients. The weighted mean time to progression was 23.66 weeks (standard deviation, 4.37) and the median was 26 weeks (range, 13–39). Interestingly, combined trastuzumab plus vinorelbine treatment showed a lower mean and median time to progression (20.59 and 19.57 weeks, respectively), whereas trastuzumab plus capecitabine yielded a mean time to progression of 30.33 weeks.

Conclusions

The added value of the present study has been to provide a quantitative summary measure of time to progression which can be used for comparisons between current and future available regimens.

HERMIONE: a randomized Phase 2 trial of MM-302 plus trastuzumab versus chemotherapy of physician's choice plus trastuzumab in patients with previously treated, anthracycline-naïve, HER2-positive, locally advanced/metastatic breast cancer

Background

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer is a particularly aggressive form of the disease, and ultimately progresses in patients with metastases on standard therapies. Anthracyclines, such as doxorubicin, are an effective treatment for HER2-positive breast cancer, particularly when administered in combination with trastuzumab – however, doxorubicin-related cardiotoxicity has limited its use. Many patients are therefore never treated with anthracyclines, even upon disease progression, despite the potential for benefit. MM-302 is a novel, HER2-targeted antibody–liposomal doxorubicin conjugate that specifically targets HER2­overexpressing cells. Preclinical and Phase 1 data suggest that MM-302, as a monotherapy or in combination with trastuzumab, could be effective for managing previously treated, anthracycline-naïve, HER2-positive breast cancer, without the cardiotoxicity observed with free doxorubicin formulations.

Methods/Design

HERMIONE is an open-label, multicenter, randomized (1:1) Phase 2 trial of MM-302 plus trastuzumab versus chemotherapy of physician’s choice (gemcitabine, capecitabine, or vinorelbine) plus trastuzumab planned to enroll 250 anthracycline-naïve patients with locally advanced/metastatic HER2-positive breast cancer. Key inclusion criteria are: previous treatment with trastuzumab (with or without pertuzumab) in any setting; refractory or intolerant to pertuzumab (refractory to pertuzumab defined as progression in the locally advanced or metastatic setting, or disease recurrence during or within 12 months of completing pertuzumab-containing neoadjuvant and/or adjuvant therapy); and disease progression on, or intolerant to, ado-trastuzumab emtansine for locally advanced or metastatic disease. The trial is currently being conducted at sites in the USA, Canada, and Western Europe. Treatment will be administered in 21-day cycles, and will be continued until disease progression or unacceptable toxicity. The primary endpoint is independently assessed progression-free survival (PFS). Tumor response will be assessed every 6 weeks, and defined according to RECIST v1.1. Secondary endpoints include investigator-assessed PFS, overall survival (OS), OS rates at 6 months and 1 year, objective response rates, safety and tolerability, quality of life, and the pharmacokinetic profile of MM-302 plus trastuzumab.

Discussion

The HERMIONE study will evaluate the efficacy and safety of MM-302 plus trastuzumab in patients with refractory HER2-positive advanced/metastatic breast cancer for whom there are no standard of care therapies with a proven survival advantage.

Trial Registration

Clinicaltrials.gov identifier: NCT02213744. Registration date: 06AUG2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2385-z) contains supplementary material, which is available to authorized users.

Pharmacokinetic Properties of Anticancer Agents for the Treatment of Central Nervous System Tumors: Update of the Literature

Despite significant improvement in outcomes for patients with hematologic malignancies and solid tumors over the past 10 years, patients with primary or metastatic brain tumors continue to have a poor prognosis. A primary reason for this is the inability of many chemotherapeutic drugs to penetrate into the brain and brain tumors at concentrations high enough to exert an antitumor effect because of unique barriers and efflux transporters. Several studies have been published recently examining the central nervous system pharmacokinetics of various anticancer drugs in patients with primary and metastatic brain tumors. To summarize recent advances in the field, this review critically presents studies published within the last 9 years examining brain and cerebrospinal fluid penetration of clinically available anticancer agents for patients with central nervous system tumors.

Clinical outcomes and cardiac safety of continuous antiHer2 therapy in c-erbB2-positive metastatic breast cancer patients

BACKGROUND

To explore clinical outcomes and cardiac safety of continuous antiHer2 therapy.

PATIENTS AND METHODS

This retrospective study evaluates overall survival (OS), time to treatment failure (TTF), and cardiac safety of 80 consecutive Her2-positive metastatic breast cancer (MBC) patients that received ≥ 12 months of therapy with trastuzumab, followed by lapatinib-based or trastuzumab-based therapy.

RESULTS

All patients received trastuzumab as first antiHer2 therapy; 54% received lapatinib in the second or subsequent line. Median OS was 34 months (12-120 months). Median OS was 48 months in the subgroup of 43 patients who received lapatinib and 26 months in the 37 patients who did not. Median TTF was shorter for lapatinib. There were three cardiac events and trastuzumab-based chemotherapy (CT) was interrupted in one patient because left ventricular ejection fraction (LVEF) decreased to ≤ 40%.

CONCLUSION

Continuous antiHer2 therapy provides good clinical outcomes, especially in those patients who received lapatinib. Cardiac dysfunction was a rare event, reversible, associated to trastuzumab and not related to treatment duration.

Drug resistance and the role of combination chemotherapy in improving patient outcomes

Resistance to cancer chemotherapy is a common phenomenon especially in metastatic breast cancer (MBC), a setting in which patients typically have had exposure to multiple lines of prior therapy. The subsequent development of drug resistance can result in rapid disease progression during or shortly after completion of treatment. Moreover, cross-class multidrug resistance limits patient treatment choices, particularly in a setting where treatments options are few. One attempt to minimize the impact of drug resistance has been the concurrent use of two or more chemotherapy agents with unrelated mechanisms of action and differing modes of drug resistance, with the intent of blocking the development of multiple intracellular escape pathways essential for tumor survival. Within the past decade, an array of mechanistically diverse agents has augmented the list of combination regimens that may be both synergistic and efficacious in pretreated MBC. The aim of this paper is to review mechanisms of resistance to common chemotherapy agents and to consider current combination treatment options for heavily pretreated and/or drug-resistant patients with MBC.

Impact of HER-2-targeted therapy on overall survival in patients with HER-2 positive metastatic breast cancer

Upon disease progression on trastuzumab-based therapy, patients with HER-2 positive metastatic breast cancer (MBC) may switch to lapatinib or continue on trastuzumab. We aimed to assess the impact of both strategies on overall survival (OS) in all patients treated for HER-2 positive MBC at the Medical University Vienna from 1999 until 2009. A total of 201 patients were identified from a breast cancer data base. Of these 115 (57.2%) received multiple lines of trastuzumab-based therapy, whereas 58 (28.9%) were treated with a single line. A control group of 28 patients (13.9%) had never received trastuzumab as they were treated before 1999, when trastuzumab was registered. OS from diagnosis of metastatic disease was defined as primary study endpoint. Trastuzumab significantly prolonged OS in HER-2 positive MBC (41 versus 13 months; p < 0.001). Administration of multiple lines further improved OS; this, however, did not reach statistical significance (47 versus 28 months; p = 0.069). Positive estrogen receptor (ER) status (HR 1.6; 95% CI 1.13-2.27) was associated with better outcome compared to negative estrogen receptor status (p = 0.02). Addition of lapatinib did not improve OS significantly in patients with prior trastuzumab-based therapy (62 versus 47 months; p = n.s.). Patients receiving lapatinib after diagnosis of BM, however, experienced an improvement of OS (22 versus 5 months; p = 0.022). Trastuzumab improves OS in patients with HER-2 positive MBC with further nonsignificant improvement when administered in multiple lines. Lapatinib did not further improve OS in the entire population; however, lapatinib might improve OS in patients with BM.

Treating breast cancer in the 21st century: emerging biological therapies

For many years, the medical treatment of breast cancer was reliant solely on cytotoxic chemotherapy. However, over the past twenty years, treatment has evolved to a more target-directed approach. We now employ tailored therapy based on the presence or absence of receptors for estrogen, progesterone, and human epidermal growth factor 2 (HER2). We expect this trend to continue, as agents that use novel approaches to target HER2, as well as targeting different portions of the HER signaling pathway, are in various stages of development. Notably, pertuzumab, a humanized monoclonal antibody that binds to a different domain of the extracellular portion of the HER2 receptor than trastuzumab, was recently approved for use, as was lapatinib, a small-molecule tyrosine kinase inhibitor. Patients with triple negative breast cancer, particularly those with the BRCA mutation, have more limited treatment options and carry a worse prognosis than those who are hormone receptor positive. However, recent data has shown that PARP inhibitors may have significant anti-tumor effect in those with this subtype of breast cancer. Novel agents that inhibit mTOR, PI3K, the insulin-like growth factor, heat shock protein 90, and histone deacetylase have shown promise in phase I-III trials and offer exciting new possibilities for the treatment of this often fatal disease. As we are presented with an ever increasing number of treatment options, the timing and combinations of therapeutic agents used becomes ever more complex in the age of personalized care, but we are hopeful that ultimately this will lead to improved patient outcomes.

A pooled analysis of 2618 patients treated with trastuzumab beyond progression for advanced breast cancer

BACKGROUND

In HER2+ MBC, continuing trastuzumab (T) after the progression during a first-line T-based regimen, represents 1 of the possible strategies, even if few data from randomized trials exist in this setting.

MATERIALS AND METHODS

The authors have performed a systematic review through PubMed, including all prospective and retrospective publications exploring the efficacy of a T-based second-line therapy in HER2+ MBC patients treated beyond progression with a first-line T-containing treatment. Pooled estimates of the RR, TTP, and OS were calculated.

RESULTS

A total of 29 studies (4 randomized controlled phase III trials, 2 observational studies, 8 prospective nonrandomized trials, and 15 retrospective case series) were retrieved for a total of 2618 patients. All were treated with a second-line, T-based treatment beyond progression with a first-line T-based chemotherapy. Overall, the median RR, TTP, and OS obtained from the selected articles were 28.7%, 7, and 24 months.

CONCLUSIONS

This pooled analysis confirms that continuing T beyond the first progression continues to be 1 of the effective and preferred choices in HER2+ MBC, failing a (T-based) first-line regimen.

What is the best choice of partner chemotherapy with trastuzumab for metastatic breast cancer?

The HER2 gene and its role in pathogenicity in human breast cancer were detected in the 1980s. Trastuzumab is a monoclonal antibody directed against the HER2 membrane receptor. The aim of this article is to describe chemotherapy-trastuzumab combinations that have been evaluated in patients with HER2-positive metastatic breast cancer, and to define the possible standards and options.

Proteomic approach reveals FKBP4 and S100A9 as potential prediction markers of therapeutic response to neoadjuvant chemotherapy in patients with breast cancer

Although doxorubicin (Doxo) and docetaxel (Docet) in combination are widely used in treatment regimens for a broad spectrum of breast cancer patients, a major obstacle has emerged in that some patients are intrinsically resistant to these chemotherapeutics. Our study aimed to discover potential prediction markers of drug resistance in needle-biopsied tissues of breast cancer patients prior to neoadjuvant chemotherapy. Tissues collected before chemotherapy were analyzed by mass spectrometry. A total of 2,331 proteins were identified and comparatively quantified between drug sensitive (DS) and drug resistant (DR) patient groups by spectral count. Of them, 298 proteins were differentially expressed by more than 1.5-fold. Some of the differentially expressed proteins (DEPs) were further confirmed by Western blotting. Bioinformatic analysis revealed that the DEPs were largely associated with drug metabolism, acute phase response signaling, and fatty acid elongation in mitochondria. Clinical validation of two selected proteins by immunohistochemistry found that FKBP4 and S100A9 might be putative prediction markers in discriminating the DR group from the DS group of breast cancer patients. The results demonstrate that a quantitative proteomics/bioinformatics approach is useful for discovering prediction markers of drug resistance, and possibly for the development of a new therapeutic strategy.

Blockade of the HER family of receptors in the treatment of HER2-positive metastatic breast cancer

Breast cancer is the most common type of cancer among women and the second leading cause of cancer death in the United States. Metastatic breast cancer is considered incurable, and treatment is aimed at palliating symptoms, achieving remission, and prolonging survival. Treatment options for metastatic disease vary based on tumor surface markers and clinical factors in an individual patient and include cytotoxic chemotherapy, hormonal therapy, biological therapy, or some combination of these. An important molecular determinant of therapy is the human epidermal growth factor receptor 2 (HER2) positivity of the tumor, which affects response to HER2-targeted treatment. HER2 is a member of the human epidermal growth factor receptor family of receptor tyrosine kinases, also known as the HER family, which activates signaling that promotes tumorigenic cellular processes such as proliferation and evasion of apoptosis. Several targeted agents, including monoclonal antibodies and tyrosine kinase inhibitors that inhibit one or more HER family receptors have been developed that affect signaling through this pathway. Some of these, such as trastuzumab and lapatinib, have been approved for breast cancer treatment. Resistance to therapy is a challenge that limits the duration of benefit achieved with these agents. Therefore, combinations of HER family-targeted agents with other therapies such as cytotoxic agents, hormonal therapy, or inhibitors of other cellular pathways, are being developed to exploit synergy and overcome resistance mechanisms. Here we review the HER family-targeted agents currently approved or in development for HER2-positive metastatic breast cancer with a focus on strategies to overcome tumor resistance.

Current neoadjuvant treatment options for HER2-positive breast cancer

Approximately one quarter of patients with breast cancer demonstrate amplification of the human epidermal receptor type 2 (HER2) gene, the expression of which is associated with a relatively poor prognosis independent of other clinical and pathologic variables. Trastuzumab, a humanized recombinant monoclonal antibody specifically directed against the HER2 receptor, has been shown to be biologically active and of considerable clinical utility in HER2-positive breast cancer patients. Neoadjuvant chemotherapy has been used in breast cancer to downstage the tumor and increase the opportunity for breast-conserving surgery. Preoperative chemotherapy can also serve as an in vivo testing of chemotherapy sensitivity. Additionally, a pathologic complete response is usually a surrogate marker of disease-free survival. Following the successful use of trastuzumab in the metastatic and adjuvant settings, many clinical trials have recently reported the successful use of anti-HER2 therapy in combination with different chemotherapy regimens in the neoadjuvant setting with a significantly higher pathologic complete response. With the recent introduction of new anti-HER2 drugs, interest has shifted toward dual HER2 blockade. Two such studies were recently reported, both showing a significant advantage of dual anti-HER2 therapy using lapatinib or pertuzumab in addition to trastuzumab and chemotherapy. However, several key questions need to be investigated further, such as the preferred combination chemotherapy and the optimal duration of trastuzumab in patients who achieve a pathologic complete response following preoperative chemotherapy with trastuzumab. These issues and others are discussed in this review.

Phase II Study of Vinorelbine Plus Trastuzumab in HER2 Overexpressing Metastatic Breast Cancer Pretreated with Anthracyclines and Taxanes

Purpose

The role of first-line trastuzumab-based therapy has been firmly established in patients with human epidermal growth factor receptor-2 (HER2) positive metastatic breast cancer. In this trial, we evaluated the efficacy and safety of a vinorelbine and trastuzumab combination chemotherapy in patients who were pretreated with anthracyclines and taxanes.

Methods

Thirty-three patients with HER2 overexpressing metastatic breast cancer, all of whom had previously been treated with anthracyclines and taxanes, were included in this study. The patients were treated with 25 mg/m² of vinorelbine (over a 15-minute infusion) on days 1 and 8 every 3 weeks. Additionally, trastuzumab was administered at an initial dose of 4 mg/kg over 90 minutes, and was subsequently administered at weekly doses of 2 mg/kg (over 30 minutes).

Results

The median age of the patients was 53 years (range, 39-72 years). The overall response rate was 30.3% (10 patients; 95% confidence interval [CI], 23-57%). The median time to progression was 6.8 months (95% CI, 5.3-8.2 months). The median overall survival was 12.4 months (95% CI, 10.3-14.6 months). In the 194 cycles of treatment, the incidence rates of grade ≥3 neutropenia and anemia were 7.2% and 1.0%, respectively. Neutropenic fever was detected in three cycles (1.5%). The non-hematological toxicities were not severe: grade 1 or 2 nausea or vomiting was detected in 15.2%, and grade 2 neuropathy was noted in 6.1% of patients. None of the patients experienced any serious cardiac toxicity, and no treatment-related deaths occurred.

Conclusion

These results show that a combination chemotherapy consisting of vinorelbine and trastuzumab is useful in patients with HER2-overexpressing metastatic breast cancer who were pretreated with anthracyclines and taxanes, with a favorable toxicity profile.

Trastuzumab emtansine: a novel antibody-drug conjugate for HER2-positive breast cancer

INTRODUCTION

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate (ADC) that combines intracellular delivery of the potent cytotoxic agent, DM1 (a derivative of maytansine) with the antitumor activity of trastuzumab. While there are several ADCs in Phase III development, T-DM1 is the only one in which the targeting antibody has antitumor properties. T-DM1 is also the only ADC that is directed toward the human EGFR 2 (HER2). Effective therapies are limited in HER2-positive advanced or metastatic breast cancer (MBC), particularly following progression on available HER2-targeted therapies.

AREAS COVERED

The mechanisms of action, preclinical efficacy and clinical profile of T-DM1 are reported. The latest preclinical and clinical data for T-DM1 are examined.

EXPERT OPINION

T-DM1 has significant antitumor potency in vitro and in vivo, which is maintained in tumors resistant to trastuzumab or lapatinib. In Phase I and II trials, T-DM1 provided objective tumor responses and was well tolerated across various lines of therapy in patients with HER2-positive MBC. In addition, it showed similar efficacy to trastuzumab plus docetaxel in first-line MBC. Ongoing trials (including two Phase III studies) are investigating T-DM1 as single-agent therapy or combined with other chemotherapeutic or biologic agents, and the results should help to define the place of T-DM1 within current treatment algorithms for HER2-positive disease.

Algorithms for the treatment of patients with metastatic breast cancer and prior exposure to taxanes and anthracyclines

At present, metastatic breast cancer (MBC) remains an incurable disease, with the goals of care aimed at maximizing the patient's duration and quality of life. Treatment options for a patient with MBC have become more efficacious and numerous. In addition to endocrine and chemotherapy agents, a number of targeted agents, including trastuzumab and bevacizumab, are available. The option to use novel agents combined with a multitude of standard chemotherapies has further enhanced the landscape of therapeutic options. As such, specific regimens must be evaluated within the framework of the individual patient, answering such questions as whether to treat with sequential single agents or combination regimens as well as which agents to use and in what sequence. The concept of personalized care is even more apparent in the setting of MBC, where the goal of palliation is intrinsically more nuanced than that of curative intent. This review will broadly assess the evidence for current treatment options with attention to varying clinical scenarios. Ultimately, delivering quality of care necessitates balancing an understanding of evidence-based data with sensitive attention to quality-of-life goals.

Rational use of trastuzumab in metastatic and locally advanced breast cancer: implications of recent research

The management of HER2-positive metastatic breast cancer, a disease renowned for its aggressive natural history, has been revolutionized by the introduction of trastuzumab. Indeed, outcomes for patients with HER2-positive advanced breast cancer are now equivalent to, if not better than, those of their HER2-negative counterparts. Since the pivotal registration trial, a wealth of new clinical data has emerged regarding the use of trastuzumab in a variety of clinical contexts - adding to the evidence but also highlighting areas of uncertainly and debate. These include the optimal partner chemotherapy(ies) to trastuzumab; the effectiveness of combining trastuzumab with endocrine therapy; the benefits of continuing trastuzumab after progression on a trastuzumab-containing regimen; and the role of trastuzumab in locally advanced and inflammatory breast cancer. In this paper we review major clinical trials addressing these questions, clinical recommendations that can be made as a result, and the strength of evidence that supports them. Finally, we identify areas of ongoing uncertainty, and propose recommendations for future research in this field.

Overcoming taxane and anthracycline resistance

With more and more breast cancer (BC) patients receiving taxanes and anthracyclines in the adjuvant setting, the number of patients resistant to these drugs is rising. Herein, we review cellular mechanisms (e.g., overexpression of drug efflux pumps) that are associated with clinical anthracycline and/or taxane-resistant BC. We also discuss therapeutic approaches that have received Food and Drug Administration approval in this setting or are in clinical development, including targeted agents that do not employ a cytotoxic mechanism, as well as novel chemotherapeutics such as the epothilones, a class of microtubule stabilizers less susceptible to common cellular resistance mechanisms.

Therapeutic options for metastatic breast cancer

Metastatic breast cancer (MBC) remains an incurable disease despite ongoing therapeutic advances. Recently there has been progress extending the range of available cytotoxic chemotherapy drugs and optimizing their scheduling. In addition, a greater understanding of tumor biology has led to the development of a number of targeted therapies. Several of these newer agents, such as trastuzumab, lapatinib and bevacizumab, have demonstrated activity in combination with chemotherapy and have improved the prognosis of patients with MBC. We hope that further progress elucidating the pathophysiology and biology of MBC will continue to lead to corresponding advances in treatment.

HER2-targeted therapy in breast cancer. Monoclonal antibodies and tyrosine kinase inhibitors

There is strong clinical evidence that trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor (HER) two tyrosine kinase receptor, is an important component of first-line treatment of patients with HER2-positive metastatic breast cancer. In particular the combination with taxanes and vinorelbine has been established. In the preoperative setting inclusion of trastuzumab has significantly increased the pathological complete response rate. Results from large phase III trials evaluating adjuvant therapy in HER2-positive early breast cancer indicate that the addition of trastuzumab to chemotherapy improves disease-free and overall survival. The use of lapatinib, a dual tyrosine kinase inhibitor of both HER1 and HER2, in combination with capecitabine in the second-line treatment of HER2-positive patients with metastatic breast cancer previously treated with trastuzumab has been established. There is modest, but still insufficient, support that the compound passes the blood-brain barrier. Several trials are ongoing both in the adjuvant and metastatic settings and we have to await the results of these to clarify the role of trastuzumab and lapatinib. The clinical problem of tumours developing resistance to HER2-directed therapy is becoming increasingly important. Several issues about optimal selection of patients, prevention of resistance and use of different treatment options are still unresolved. In this article, we summarise the current knowledge on clinical evidence of HER2-directed therapy and the potential mechanisms of underlying resistance, including the possible clinical implications and review new therapeutic options.

Loading doses for costly cancer biologicals: a cause for concern or tilting at windmills?

The emergence of novel, effective but expensive biological therapies is significantly improving outcomes for many patients with cancer, but also substantially increasing treatment costs. Monoclonal antibodies with long half-lives have often been developed using loading doses to hasten the achievement of a therapeutic dose. Although the benefits of loading doses have not been proven, we caution against abandoning this practice on uncertain theoretical grounds. Rather, the issue of loading doses should be seen in the broader context of how best to define the optimal dose, schedule and duration of treatment through novel clinical trial designs.