Continuing trastuzumab beyond disease progression: outcomes analysis in patients with metastatic breast cancer

A molecular link between diabetes and breast cancer: Therapeutic potential of repurposing incretin-based therapies for breast cancer

Female breast cancer recently surpassed lung cancer and became the most commonly diagnosed cancer worldwide. As per the recent data from WHO, breast cancer accounts for one out of every 8 cancer cases diagnosed among an estimated 2.3 million new cancer cases. Breast cancer is the most prevailing cancer type among women causing the highest number of cancer-related mortality. It has been estimated that in 2020, 68,5000 women died due to this disease. Breast cancers have varying degrees of molecular heterogeneity; therefore, they are divided into various molecular clinical sub types. Recent reports suggest that type 2 diabetes (one of the common chronic diseases worldwide) is linked to the higher incidence, accelerated progression, and aggressiveness of different cancers; especially breast cancer. Breast cancer is hormone-dependent in nature and has a cross-talk with metabolism. A number of antidiabetic therapies are known to exert beneficial effects on various types of cancers, including breast cancer. However, only a few reports are available on the role of incretin-based antidiabetic therapies in cancer as a whole and in breast cancer in particular. The present review sheds light on the potential of incretin based therapies on breast cancer and explores the plausible underlying mechanisms. Additionally, we have also discussed the sub types of breast cancer as well as the intricate relationship between diabetes and breast cancer.

Cardioncological Approach for Trastuzumab Therapy in Breast Cancer Patients With Cardiotoxicity: Impact on Adherence and Clinical Outcome

Background

Treatment with Trastuzumab is associated with cardiotoxicity. If Trastuzumab could be administered in a safe manner to patients who develop a reduced left ventricular ejection fraction (EF) of < 50% remains poorly understood.

Objective

To evaluate the impact of a cardioncological approach in terms of adherence and continuation of oncological therapy with Trastuzumab.

Methods and Results

Internal databases of candidates for trastuzumab chemotherapy with evidence of cardiotoxicity according to echocardiographic criteria were retrospectively evaluated. Eighty-four female patients (age 51.7 years, 95% CI 49.5–53.8), were finally included. Patients were divided to receive a standard (n 27) or cardioncological (n 57) scheme. Baseline EF values were within normal limits (60.9, 95% CI 60 - 61.9%; p=0.5 between groups). The nadir of EF observed during trastuzumab therapy was more pronounced in the standard care group (40.6, 95% CI 37.3–43.9% vs. 46.3, 95% CI 44.3–48.3%; p=0.002). At re-challenge, after cardiotoxicity detection, all patients in the cardioncological arm resumed and completed trastuzumab therapy (p<0.0001). An overall reduction of EF was observed at the final evaluation (p <0.0001 vs. baseline). Cardioncological approach was the only independent determinant of ΔEF from baseline to final evaluation (R²0.12; p=0.004). We observed a total of 13 (15%) HF events, seven (26%) in the standard, and six (10%) in the cardioncological approach group (p =0.1). Patients in the cardioncological approach arm had a better outcome (Log Rank Chi-squared 4.89; p=0.02).

Conclusions

A targeted cardioncological approach, in patients with evidence of cardiotoxicity during HER-2 inhibitor therapy, could favorably influence the oncological management of breast cancer patients, reducing the adverse cardiovascular impact of chemotherapy.

Therapeutic Strategies for Human Epidermal Receptor-2 Positive Metastatic Breast Cancer: A Literature Review

Breast cancer is a frequently occurring malignancy in women. Immunologically, breast cancers can be classified into four subtypes depending on the types of receptors present and their expression profiles. These are estrogen positive, progesterone positive, human epidermal growth factor receptor type 2 (HER2) positive, and triple-negative as identified by immunohistochemistry. This classification is the basis of response to treatment, prognosis, and survival. With the identification of HER2 receptor overexpression, targeted therapies with anti-HER2 agents have been developed. The first-line therapy approved for HER2 positive tumors is trastuzumab and pertuzumab linked to taxane and further treatment with an antibody-drug conjugate to achieve satisfactory outcomes. Tyrosine kinase overexpression can be treated with lapatinib, which has also been approved for improving survival and is used in combination with capecitabine. Acquired resistance in HER2 positive tumors is shown in many cases due to genetic or epigenetic modifications. Therefore, it is very important to plan therapeutic strategies and design effective treatment approaches. For a long time, only two agents, trastuzumab and lapatinib, have been approved by the Food and Drug Administration (FDA) for the treatment of HER2 positive breast cancers. There has been no appropriate treatment for trastuzumab resistance and its failure to reduce tumor growth. Lapatinib was approved by the FDA in 2007 for HER2 positive breast cancer. Three existing therapy options after trastuzumab resistance was proposed by clinicians: continuation of trastuzumab, starting therapy with lapatinib, and the synergistic use of trastuzumab and lapatinib.

There have been several effective therapies proposed for HER2 positive breast cancers in correlation with clinical trials. Discovering the mechanisms of trastuzumab resistance would increase its response to therapy and better clinical outcome. Clinicians are being continuously challenged by the resistance mechanisms and bioavailability of the drugs in the treatment of metastatic breast cancers. The addition of new drugs to the chemotherapeutic regimen increases the complexity, burden of side effects, and chances of relapse. Novel anti-HER2 agents have been directed towards therapy making a major paradigm shift.

The Management of Oligoprogression in the Landscape of New Therapies for Metastatic Melanoma

Background: A limited degree of progression after a response to treatment is labelled as oligoprogression and is a hot topic of metastatic melanoma (MM) management. Rogue progressive metastases could benefit from local treatment, which could allow the continuation of ongoing systemic therapy, also known as treatment beyond progression (TBP). Methods: We retrospectively reviewed 214 selected MM patients who developed oligoprogression during treatment with v-Raf murine sarcoma viral oncogene homolog B (BRAF)/mitogen-activated-extracellular signal-regulated kinase (MEK) or programmed cell death protein 1 (PD-1) inhibitors and received a local treatment continuing TBP. We performed univariate and multivariable analyses to assess the association between therapy outcomes and a series of clinical and biological features. Results: We identified 27 (10%) oligoprogressed patients treated locally with surgery (14), radiosurgery (11), and electrochemotherapy (2). TBP included PD-1 inhibitors (13) and BRAF/MEK inhibitors (14). The median progression-free survival post oligoprogression (PFSPO) was 14 months (5-19 95% confidence interval (C.I.)). In the univariate analysis, a significantly longer PFSPO was associated with complete response (CR), Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0, neutrophils/lymphocytes ratio (N/L) <2, and progression-free survival (PFS) at oligoprogression >11 months. Nevertheless, in the multivariable analysis, only CR and N/L <2 were found to be associated with longer PFSPO. Conclusions: In selected patients, local treatments contribute to controlling oligoprogression for a long time, allowing the continuation of systemic treatment and prolongation of overall survival (OS). Increasing biological and clinical knowledge is improving the accuracy in identifying patients to apply for local ablative therapies.

Trastuzumab treatment after progression in HER2-positive metastatic breast cancer following relapse of trastuzumab-based regimens: a meta-analysis

Background: This meta-analysis assessed the safety and effectiveness of retreatment with trastuzumab in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (HER2+MBC). Materials and methods: Randomized controlled trials (RCTs) and cohort studies that compared the clinical outcomes of continuation and termination of trastuzumab treatment in HER2+MBC after failure of trastuzumab-based regimens were analyzed. Pooled estimates of time to progression (TTP) survival, overall survival (OS), the incidence of adverse events and central nervous system (CNS) perturbations were determined. Results: Four RCTs and six cohort studies with 2,409 patients were identified. The continuation of trastuzumab presented a statistical significance in prolonging TTP (HR 0.88; 95% CI: 0.82-0.94; P<0.000) and OS (HR 0.87; 95% CI: 0.82-0.93; P<0.000). Furthermore, retreatment with trastuzumab did not add to the risk of cardiac events (relative risk, 2.48; 95% CI: 0.86-7.15) or the incidence of CNS metastasis (P=0.83). Conclusion: Our findings confirm the clinical benefits and safety of retreatment therapy with trastuzumab for HER2-positive patients with metastatic cancer of the breast that had progressed during trastuzumab-based treatment regimens.

Cardiac outcomes of trastuzumab therapy in patients with HER2-positive breast cancer and reduced left ventricular ejection fraction

PURPOSE

Asymptomatic decline in left ventricular ejection fraction (LVEF) or heart failure (HF) occurs in up to 25% of patients treated with trastuzumab and can result in incomplete breast cancer therapy. The cardiac safety of continuing trastuzumab in patients with asymptomatic LVEF decline is unknown. We report the cardiac outcomes of patients treated with trastuzumab after a significant asymptomatic LVEF decline.

METHODS

Patients with HER2-positive breast cancer and asymptomatic LVEF decline to < 50% during trastuzumab were identified from an institutional echocardiogram database. Patients who received trastuzumab with a LVEF < 50% were classified as the continued group, whereas patients who had trastuzumab held until LVEF improved to ≥ 50% or who had trastuzumab permanently discontinued were classified as the interrupted group. Cardiac events were defined as HF (New York Heart Association class III-IV) or cardiovascular death.

RESULTS

Sixty patients were included; the median age was 54 years. In 23 patients who continued trastuzumab, 14 (61%) tolerated trastuzumab without a cardiac event, 6 (26%) developed worsening LVEF (range 25-42%) leading to trastuzumab discontinuation, and three (13%) developed a cardiac event (1 HF, 2 possible/probable cardiovascular deaths). In 37 patients with interrupted trastuzumab, 15 (41%) were re-challenged with trastuzumab after LVEF improved to > 50%, 21 (57%) were not re-challenged, and one (3%) developed HF. More patients in the continued trastuzumab group had metastatic disease (39% vs. 5%, p = 0.002). The final LVEF after median follow-up of 633 days was similar between patients with trastuzumab continuation versus interruption (54% vs. 56%, p = 0.29).

CONCLUSION

Continuation of trastuzumab after an asymptomatic LVEF decline to < 50% in patients who are expected to benefit from additional anti-HER2 therapy is a promising approach that warrants further investigation.

Metastatic Breast Cancer Treated with Lapatinib with a Prolonged Benefit: A Case Report and a Review of Therapeutic Options Available

A 53-year-old woman was treated, after trastuzumab progression of HER2-positive metastatic disease, with capecitabine plus lapatinib and subsequently with lapatinib alone. To date, she has had persistent remission of disease since 2009.

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.

Long-term outcomes of tyrosine kinase inhibitor discontinuation in patients with metastatic renal cell carcinoma

PURPOSE

The purpose of the current study was to evaluate the clinical outcomes of patients with metastatic renal cell carcinoma (mRCC) who interrupted vascular endothelial growth factor receptor tyrosine kinase inhibitor (VEGFR-TKI) therapy.

METHODS

A retrospective analysis of medical records was performed on all patients with mRCC treated with VEGFR-TKIs between January 2008 and July 2014 (n = 505). Patients who achieved stable disease (SD) or a better response under TKI and later discontinued TKI treatment for any reason with the exception of disease progression were included in the analysis.

RESULTS

We identified 32 patients (sunitinib = 20, sorafenib = 7, and pazopanib = 5). The responses to VEGFR-TKIs were complete response (CR, n = 4), partial response (PR, n = 11), SD (n = 15), and controlled but nonmeasurable response (n = 2). Median time to TKI discontinuation from the initiation of VEGFR-TKI therapy was 16.6 months (95 % CI 12.8-20.3), and the main cause of VEGFR-TKI discontinuation was toxicity (n = 19, 59.4 %). At the time of analysis, 16 patients had disease progression and one patient died. With a median follow-up duration of 51.7 months (range 11.5-87.6), median progression-free survival (PFS) after TKI discontinuation was 20.2 months (95 % CI 6.4-34.0). In multivariate analysis, the duration of TKI therapy (<1 year) before TKI discontinuation was an independent significant prognostic factor of poor PFS (p = 0.045). Among 11 patients who were retreated with the same TKI, two patients (18.2 %) achieved PR and nine achieved SD (81.8 %).

CONCLUSIONS

VEGFR-TKI could be interrupted at least temporarily when clinically warranted in patients with mRCC sufficiently controlled by TKIs.

Risk factors for disease progression in HER2-positive breast cancer patients based on the location of metastases

Introduction

Trastuzumab therapy significantly improves progression-free and overall survival in HER2-positive [HER2(+)] breast cancer (BC) patients. However, in most patients with HER2(+) metastatic BC, the disease progress occurred. The aim of this study was to evaluate the clinicopathological risk factors for progression in HER2-positive breast cancer patients during trastuzumab therapy.

Material and methods

The analysis included medical records of HER2(+) metastatic BC patients treated with trastuzumab between 2006 and 2013.

Results

The most common site of progression during trastuzumab therapy were lungs 25 (39%), central nervous system (CNS) 8 (13%), skin 9 (14%), locoregional lymph nodes 19 (30%), liver 18 (28%) and bone 17 (27%). Patients with lung metastases significantly more often had a history of cancer in the family than women with other metastasis sites (24% vs. 2.6%), p = 0.048. Metastases to lungs occurred also more often during therapy containing trastuzumab with chemotherapy than trastuzumab alone 17/8 (58% vs. 41%), p = 0.043. Central nervous system metastases were observed insignificantly more frequently in postmenopausal women than premenopausal patients 8/0 (22% vs. 0%), p = 0.093. There was reported a tendency to liver metastases in ER-negative tumors 13/20 (72% vs. 44%, p = 0.053). Bone metastases were associated with the positive steroid receptor status (p = 0.019) and second neoplasm in history (p = 0.06).

Conclusions

Risk factors for disease progression were the menopausal status (CNS metastases), steroid receptor status (liver, lymph nodes and bone metastases), history of cancer in the family (lung metastases) and history of cigarette smoking (liver metastases).

Vemurafenib for BRAF V600 mutated advanced melanoma: results of treatment beyond progression

BACKGROUND

Selective BRAF inhibition (BRAFi) by vemurafenib or dabrafenib has become approved standard treatment in BRAF V600 mutated advanced stage melanoma. While the response rate is high, the response duration is limited with a progression-free survival (PFS) of 5-6months. Our observation of accelerated disease progression within some patients after stopping vemurafenib treatment has fostered the idea of treatment beyond progression (BRAFi TBP).

METHOD

In this retrospective study, we analysed 70 metastatic melanoma patients, treated at our institute, who experienced progression after prior objective response upon treatment with vemurafenib. Thirty-five patients that continued treatment beyond progression are compared with 35 patients who stopped BRAFi treatment at disease progression.

RESULTS

Median overall survival beyond documented progression was found to be 5.2months versus 1.4months (95% confidence interval (CI): 3.8-7.4 versus 0.6-3.4; Log-Rank p=0.002) in favour of BRAFi TBP. In the multivariate survival analysis, stopping treatment at disease progression was significantly associated with shorter survival (hazard ratio: 1.92; 95% CI: 1.04-3.55; p=0.04).

CONCLUSION

Our results suggest that continuing vemurafenib treatment beyond progression may be beneficial in advanced melanoma patients, who prior to progression responded to vemurafenib.

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.

Trastuzumab mediates antibody-dependent cell-mediated cytotoxicity and phagocytosis to the same extent in both adjuvant and metastatic HER2/neu breast cancer patients

Background

Monoclonal antibodies (mAb), such as trastuzumab are a valuable addition to breast cancer therapy. Data obtained from neoadjuvant settings revealed that antibody-dependent cell-mediated cytotoxicity (ADCC) is a major mechanism of action for the mAb trastuzumab. Conflicting results still call into question whether disease progression, prolonged treatment or concomitant chemotherapy influences ADCC and related immunological phenomena.

Methods

We analyzed the activity of ADCC and antibody-dependent cell-mediated phagocytosis (ADCP) of peripheral blood mononuclear cells (PBMCs) from human epidermal growth factor receptor 2 (HER2/neu) positive breast cancer patients receiving trastuzumab therapy either in an adjuvant (n = 13) or metastatic (n = 15) setting as well as from trastuzumab treatment-naive (t-naive) HER2/neu negative patients (n = 15). PBMCs from healthy volunteers (n = 24) were used as controls. ADCC and ADCP activity was correlated with the expression of antibody binding Fc-gamma receptor (FcγR)I (CD64), FcγRII (CD32) and FcγRIII (CD16) on CD14+ (monocytes) and CD56+ (NK) cells, as well as the expression of CD107a+ (LAMP-1) on CD56+ cells and the total amount of CD4+CD25+FOXP3+ (T_reg) cells. In metastatic patients, markers were correlated with progression-free survival (PFS).

Results

ADCC activity was significantly down regulated in metastatic, adjuvant and t-naive patient cohorts as compared to healthy controls. Reduced ADCC activity was inversely correlated with the expression of CD107a on CD56+ cells in adjuvant patients. ADCC and ADCP activity of the patient cohorts were similar, regardless of treatment duration or additional chemotherapy. PFS in metastatic patients inversely correlated with the number of peripheral T_reg cells.

Conclusion

The reduction of ADCC in patients as compared to healthy controls calls for adjuvant strategies, such as immune-enhancing agents, to improve the activity of trastuzumab. However, efficacy of trastuzumab-specific ADCC and ADCP appears not to be affected by treatment duration, disease progression or concomitant chemotherapy. This finding supports the application of trastuzumab at any stage of the disease.

Which patients with metastatic breast cancer benefit from subsequent lines of treatment? An update for clinicians

The outcome of patients with metastatic breast cancer (MBC) has clearly improved over the past decades and the proportion of women living with their disease for several years is increasing. However, the usefulness of multiple lines of treatment is still debated and under evaluation. The available data from both randomized trials and large retrospective series are reviewed and discussed in order to analyze management practices, with emphasis on potential prognostic and predictive factors for clinical outcome. At present, evidence-based medicine provides some support for the use of second-line and to a lesser degree and in selected cases, third-line chemotherapy in human epidermal growth factor receptor 2 (HER2) negative MBC. Beyond third-line treatment, messages from recently reported retrospective studies also suggest a clear potential gain for women receiving further therapies after disease progression, since each line can contribute to a longer survival. In HER2-positive disease, the data from observational and retrospective studies support a clinical benefit from the use of trastuzumab beyond disease progression and emerging evidences from randomized controlled trials are leading to the introduction of newer HER2-targeted therapies in multiple lines. The question 'How many lines of treatment should we give patients?' clearly needs further research through prospective, high-quality clinical trials, aiming for a better definition of factors with prognostic and predictive role. In the meantime, the 'optimal' treatment strategy should probably be to use as many therapeutic options as possible, either in sequence or combination, to keep the best efficacy/toxicity balance, considering MBC as a chronic disease.

Drug rechallenge and treatment beyond progression--implications for drug resistance

The established dogma in oncology for managing recurrent or refractory disease dictates that therapy is changed at disease progression, because the cancer is assumed to have become drug-resistant. Drug resistance, whether pre-existing or acquired, is largely thought to be a stable and heritable process; thus, reuse of therapeutic agents that have failed is generally contraindicated. Over the past few decades, clinical evidence has suggested a role for unstable, non-heritable mechanisms of acquired drug resistance pertaining to chemotherapy and targeted agents. There are many examples of circumstances where patients respond to reintroduction of the same therapy (drug rechallenge) after a drug holiday following disease relapse or progression during therapy. Additional, albeit limited, evidence suggests that, in certain circumstances, continuing a therapy beyond disease progression can also have antitumour activity. In this Review, we describe the anticancer agents used in these treatment strategies and discuss the potential mechanisms explaining the apparent tumour re-sensitization with reintroduced or continued therapy. The extensive number of malignancies and drugs that challenge the custom of permanently switching to different drugs at each line of therapy warrants a more in-depth examination of the definitions of disease progression and drug resistance and the resulting implications for patient care.

Drug rechallenge and treatment beyond progression--implications for drug resistance

The established dogma in oncology for managing recurrent or refractory disease dictates that therapy is changed at disease progression, because the cancer is assumed to have become drug-resistant. Drug resistance, whether pre-existing or acquired, is largely thought to be a stable and heritable process; thus, reuse of therapeutic agents that have failed is generally contraindicated. Over the past few decades, clinical evidence has suggested a role for unstable, non-heritable mechanisms of acquired drug resistance pertaining to chemotherapy and targeted agents. There are many examples of circumstances where patients respond to reintroduction of the same therapy (drug rechallenge) after a drug holiday following disease relapse or progression during therapy. Additional, albeit limited, evidence suggests that, in certain circumstances, continuing a therapy beyond disease progression can also have antitumour activity. In this Review, we describe the anticancer agents used in these treatment strategies and discuss the potential mechanisms explaining the apparent tumour re-sensitization with reintroduced or continued therapy. The extensive number of malignancies and drugs that challenge the custom of permanently switching to different drugs at each line of therapy warrants a more in-depth examination of the definitions of disease progression and drug resistance and the resulting implications for patient care.

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.

The next generation of biologic agents: therapeutic role in relation to existing therapies in metastatic breast cancer

The use of more active cytotoxic agents (eg, anthracyclines and taxanes) in the adjuvant setting has impacted treatment options in metastatic breast cancer (MBC). Various new approaches to combination therapy are being investigated, including classic and novel cytotoxic agents and targeted therapies. The heterogeneous molecular pathways involved in the development of breast cancer provide numerous potential targets for therapeutic intervention. Molecular technologies have facilitated the development of various new therapies targeted at disrupting processes as diverse as angiogenesis and DNA repair. Targeted therapies have the potential to improve outcomes in MBC, and their use has increased dramatically over recent years after the introduction of human epidermal growth factor receptor 2 (EGFR2)-targeted therapy with trastuzumab. Lapatinib and bevacizumab have recently been approved for patients with MBC. Numerous other targeted agents are undergoing preclinical investigation or are being evaluated in clinical trials. The maximum benefit of targeted therapies has been realized by their combined use with cytotoxic agents. Overall, single-agent use of targeted therapies has failed to produce dramatic benefit in patients with advanced breast cancer. This article reviews the data from studies of established and emerging targeted therapies in the treatment of MBC and describes how best to incorporate these agents into current treatment paradigms.

Mechanisms of Resistance to Trastuzumab and Novel Therapeutic Strategies in HER2-Positive Breast Cancer

HER2-positive breast cancers have poorer prognosis and are prime candidates for molecular-targeted therapy because they are driven by the unique mechanism of HER2 oncogene addiction. While anti-HER2 agents such as trastuzumab and lapatinib are integral to the treatment of HER2-positive breast cancer, intrinsic and secondary resistance pose a significant challenge, underscoring the need to develop novel anti-HER2 therapies. In recent years, an array of promising and novel anti-HER2 therapeutic agents and their combinations have entered various stages of clinical development. However, questions remain on the optimal sequences of HER2-directed therapies and selection of patients for the most appropriate drug or combinations; incompletely defined mechanisms of trastuzumab action and resistance have also dampened the progress of more successful biomarker-driven treatment approaches. This paper summarizes existing preclinical and clinical evidence on the mechanisms of trastuzumab action and resistance and provides an up-to-date overview of novel HER2-directed therapies in clinical development.

Long-Term Partial Remission with Capecitabine/Trastuzumab in a Patient with Metastatic Breast Cancer Following Progression on Trastuzumab Alone

BACKGROUND: Since the introduction of trastuzumab into the treatment of Her-2/neu-positive metastatic breast cancer, cases of long-term survival have become more frequent. Even after tumor progression, trastuzumab seems to retain its antitumor activity which is potentiated by the combination with a chemotherapeutic agent. CASE REPORT: We are reporting about the unusual clinical course of a young patient with Her-2/neu-positive breast cancer, who experienced progression of pulmonary and bone metastases under treatment with trastuzumab. Upon progression, a combination therapy with capecitabine/trastuzumab was initiated, and a partial remission was achieved which has continued for over 4 years. CONCLUSION: This unusual clinical course shows that continuing trastuzumab-based therapy beyond progression is a safe, effective, and well-tolerated option which can induce long-term remissions in some patients with Her-2/neu-positive metastatic breast cancer.

Trastuzumab treatment beyond progression in advanced breast cancer: patterns of care in six Swiss breast cancer centers

BACKGROUND

Trastuzumab is an established treatment for HER2-positive breast cancer (BC). We analyzed Swiss patterns of care in patients with HER2-positive BC after disease progression on trastuzumab-containing therapy for metastatic BC (MBC).

PATIENTS AND METHODS

A retrospective analysis was performed in six Swiss BC centers. Patients with HER2-positive MBC treated with at least one infusion of trastuzumab for advanced disease between January 2006 and December 2007 were identified. Treatment patterns in first and further lines were analyzed.

RESULTS

All of the 72 identified patients received trastuzumab as their first palliative anti-HER2 therapy, either as monotherapy (n = 23) or in combination with chemotherapy (typically taxane or vinorelbine; n = 49). Median time to progression was 8.1, 8.0 and 7.9 months in the monotherapy, trastuzumab-taxane and trastuzumab-vinorelbine cohorts, respectively. After progression on first-line anti-HER2 therapy, trastuzumab was continued in 67 of 68 patients who received further therapy. One patient received second-line lapatinib plus capecitabine. The median duration of anti-HER2 therapy was 20 months. Patients received a median of 4 lines of anti-HER2 therapy.

CONCLUSIONS

Durable responses were achieved with repeated exposure to anti-HER2 therapy. In a selected patient population, trastuzumab monotherapy appears to be a reasonable first-line treatment option.

Activity and resistance of trastuzumab according to different clinical settings

Trastuzumab, a humanized monoclonal antibody directed against HER2, has shown efficacy in breast cancers; however many patients do not respond to this reagent. Here, we discuss the potential mechanisms of trastuzumab efficacy and resistance in different clinical settings as a step toward optimizing the appropriate application of this antibody. The three major antitumor mechanisms of trastuzumab, i.e., inhibition of proliferation, antibody-dependent cell cytotoxicity (ADCC) and inhibition of DNA repair, appear to be differentially operative in different clinical settings. ADCC appears to be the prevalent mechanism in trastuzumab neoadjuvant monotherapy, whereas in neoadjuvant, adjuvant or metastatic settings in which trastuzumab is combined with chemotherapy, the relative role of ADCC is probably small, considering the compromising effects of chemotherapy on the immune cells that mediate this mechanism. In neoadjuvant and adjuvant settings involving concomitant use of trastuzumab and chemotherapy, the primary mechanism at play is presumably inhibition of DNA repair by the antibody, while in sequential protocols, the antibody acts mostly by exerting cytostatic activity through inhibition of HER2-mediated tumor cell proliferation. According to the ability of the antibody to induce cytotoxic or cytostatic antitumor effects depending on the clinical setting, different criteria, i.e., RECIST for cytotoxic effect, OS, and DFS for cytostatic, must be considered in accurately estimating antibody efficacy. Moreover, since trastuzumab resistance likely depends directly on the mechanisms responsible for its antitumor activity, resistance mechanisms must also be considered with respect to the different clinical settings.

Randomized phase II study comparing efficacy and safety of combination-therapy trastuzumab and docetaxel vs. sequential therapy of trastuzumab followed by docetaxel alone at progression as first-line chemotherapy in patients with HER2+ metastatic breast cancer: HERTAX trial

BACKGROUND

Because chemotherapy for metastatic breast cancer (MBC) is associated with relevant toxicity, sequential monotherapy trastuzumab followed by cytotoxic therapy at disease progression might be an attractive approach.

METHODS

In a multicenter phase II trial, 101 patients with overexpression of human epidermal growth factor receptor 2 (HER2(+)) MBC were randomized between combination-therapy trastuzumab (Herceptin) plus docetaxel (H+D) and sequential therapy of single-agent trastuzumab followed at disease progression by docetaxel alone (H→D) as first-line chemotherapy for metastatic disease. The primary endpoint was progression-free survival (PFS) after completed sequential or combination therapy.

RESULTS

For the H+D group the median PFS was 9.4 vs. 9.9 months for the H→D group and 1-year PFS rates were 44% vs. 35%, respectively. However the overall response rates (ORRs) were 79% vs. 53%, respectively (P = .016), and overall survival was 30.5 vs. 19.7 months, respectively (P = .11). In the H→D group, response rates to monotherapy trastuzumab and subsequent docetaxel were 34% and 39%, respectively, with a median PFS during single-agent trastuzumab of 3.9 months. The incidence and severity of neuropathy were significantly higher in the H+D group. Retrospective analysis of trastuzumab treatment beyond progression (applied in 46% of patients in the H+D group and 37% in the H→D group) showed a correlation with longer overall survival in both treatment arms (36.0 vs. 18.0 months and 30.3 vs. 18.6 months, respectively).

CONCLUSION

First-line treatment in patients with MBC with H→D resulted in a similar PFS compared with H+D, but the response rate was lower and the overall survival nonsignificantly shorter.

Comparison of overall survival between the early use and delayed use of Trastuzumab therapy groups: a retrospective analysis of 128 patients with HER-2-positive advanced breast cancer

Trastuzumab has been the standard treatment in first-line treatment of HER-2-positive advanced breast cancer (H2ABC). This study explored whether the delayed and repeated use of trastuzumab could influence overall survival (OS). A total of 128 patients with H2ABC who had received at least one line of trastuzumab-based regimens were included. The primary endpoint was OS defined as from the date of first diagnosis of H2ABC to death. The median OS of initiating trastuzumab in first-line group (n = 56), in the second-line group (n = 32), and the third- or more-line group (n = 40) was 40.6 m, 39.5 m, and 38 m, respectively (P = 0.867). For patients who had received over one line of trastuzumab (n = 46), the median OS was 44 m, and for those receiving only one line (n = 67), it was 27.6 m (P = 0.059). The delayed use of trastuzumab has no negative effect on the OS of patients with H2ABC. There is a trend of improved OS over the repeated use of trastuzumab.

Treatment of metastatic breast cancer: second line and beyond

Increasing use of standard chemotherapy, especially anthracycline- and taxane-based therapies, in early-stage breast cancer has led to a corresponding increase in heavily pretreated and/or treatment-resistant cases of metastatic breast cancer (MBC). Thus, second and later lines of MBC therapy frequently involve the clinically challenging picture of progressive disease and limited treatment options. While several prognostic factors have been identified to aid treatment selection in MBC patients, treatment is palliative and aimed at prolonging survival, controlling symptoms, and maximizing patients' quality of life. No globally accepted standard exists for meeting these goals, and treatment patterns vary according to region. The list of available agents for the treatment of MBC is increasing with newer chemotherapeutic agents and molecular-targeted therapies. Within recent years, several single-agent and combination chemotherapy regimens have been shown to improve progression-free survival and reduce symptoms of disease in clinical studies in patients with resistant and/or heavily pretreated MBC. However, at present, the demonstrated benefits of these medical interventions have usually not included extension of overall survival times. It is hoped that in the near future, ongoing refinements to treatment approaches used in second-line settings and beyond will allow meaningful improvements in symptom control and survival in MBC.

Management of metastatic HER2-positive breast cancer progression after adjuvant trastuzumab therapy - current evidence and future trends

Trastuzumab is now considered the standard of care for the adjuvant treatment of human epidermal growth factor receptor-2 (HER2)-positive breast cancer patients, yet a sizable number of HER2-positive patients do not benefit from this treatment. For patients who progress on or after completion of adjuvant trastuzumab therapy, the standard of care is uncertain. Newer tyrosine kinase inhibitors and monoclonal antibodies are being evaluated in clinical trials for optimisation of treatment in this group. The interplay of HER2 and hormonal signalling pathways is being manipulated to see if response rates can be bettered. In this reveiw we explain the present role of the new molecules with a case scenario. The new anti-HER2 drugs have the potential to change clinical practise of targeting HER2 in the future. Better understanding of HER2 functions and interactions of different signalling pathways will be essential for optimal targetted therapies.

Trastuzumab and lapatinib beyond trastuzumab progression for metastatic breast cancer: strategies and pitfalls

The discovery of HER2 gene amplification and protein overexpression in approximately 15-20% of breast cancers and access to the tailored humanized antibody, trastuzumab (Herceptin), have heralded a new era in breast cancer therapy. Trastuzumab combined with chemotherapy has caused marked tumor responses and increased overall survival in patients with metastatic breast cancer, and has also increased survival in the adjuvant setting after radical surgery. However, due to many causes, trastuzumab resistance usually occurs during treatment. In this event, possible options include the replacement of trastuzumab with lapatinib, the continuation of trastuzumab after disease progression with changed chemotherapy and the suspension of the use of targeted agents. New-generation tyrosine kinase inhibitors, which have a broader target, are now considered the key to treatment for breast cancer.

[Management of metastatic HER2-positive breast cancer: present and future]

HER2-positive breast cancer accounts for 20 to 25% of breast cancers. The surexpression of this tyrosine-kinase receptor is often associated with a poor prognosis. However, the management and the outcome of these patients have changed these last ten years with trastuzumab. Despite the encouraging results obtained with this humanized monoclonal antibody directed against the HER2-receptor, used alone or in association with chemotherapy in metastatic patients, progression under trastuzumab are usually observed and resistances to this treatment are described. Thus, many other monoclonal antibodies and tyrosine-kinase inhibitors emerged. These therapeutics, used alone or in association with chemotherapy or trastuzumab have variable properties: anti-HER2 and anti-EGFR such as lapatinib, pertuzumab and neratinib; anti-EGFR such as erlotinib and gefitinib; antiangiogenesis (bevacizumab, pazopanib); anti-mTOR pathway (temsirolimus, everolimus) or inhibitor of HSP90 (tanespimycine). In this paper, we present an overview on validated targeted therapies and those which are currently under investigation and seem promising in first line or after progression under trastuzumab. Data regarding cardiotoxicity and the use of trastuzumab under particular clinical circumstances (brain metastases, pregnancy) are also reviewed.

Trastuzumab: unusual responses and toxicities

Trastuzumab has become the standard of care in the management of human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancers, both in the metastatic and adjuvant setting. Emerging data show continued efficacy of the drug even after disease progression in combination with chemotherapy. While cardiotoxicity is well recognized with trastuzumab, unusual pulmonary toxicities are becoming apparent. Cases that reflect the unusual efficacy and unusual toxicity of trastuzumab are reported.

Novel therapeutic approaches to the treatment of metastatic breast cancer

Metastatic breast cancer is ultimately an incurable disease, although recent data have shown that its incidence is decreasing and that patients with metastatic breast cancer live longer. This improvement in survival seems to be linked with the introduction of new therapeutic agents, novel combinations of existing therapies and targeted therapies. Our increasing understanding of the molecular biology of metastatic disease has allowed the development of therapies aimed at specific molecular targets. Some of these have already been approved for the treatment of metastatic breast cancer in combination with cytotoxics, and others have shown promising results regarding disease-free survival, overall response rates and time to disease progression. Given the enormous amount of information about drug discovery in cancer, it is important to be familiar with the present state of the treatment of metastatic breast cancer. The purpose of this review is to provide an update on the development of some of the most promising novel agents and treatment strategies in metastatic breast cancer.

Recent advances in systemic therapy: Advances in systemic therapy for HER2-positive metastatic breast cancer

Human epidermal growth factor receptor (HER)2 over-expression is associated with a shortened disease-free interval and poor survival. Although the addition of trastuzumab to chemotherapy in the first-line setting has improved response rates, progression-free survival, and overall survival, response rates declined when trastuzumab was used beyond the first-line setting because of multiple mechanisms of resistance. Studies have demonstrated the clinical utility of continuing trastuzumab beyond progression, and further trials to explore this concept are ongoing. New tyrosine kinase inhibitors, monoclonal antibodies, PTEN (phosphatase and tensin homolog) pathway regulators, HER2 antibody-drug conjugates, and inhibitors of heat shock protein-90 are being evaluated to determine whether they may have a role to play in treating trastuzumab-resistant metastatic breast cancer.