A phase II study of trastuzumab and capecitabine for patients with HER2-overexpressing metastatic breast cancer: Japan Breast Cancer Research Network (JBCRN) 00 Trial

Long-Term Complete Response with Single-Agent Capecitabine in Her-2-neu-Positive Metastatic Breast Cancer-A Rare Case Report

The standard treatment approach for metastatic breast cancer with HR- and Her-2-neu + disease is trastuzumab with systemic therapy. But in patients having severe cardiac dysfunction, trastuzumab is avoided. Various combination regimens are available in that setting, but no study has shown better efficacy of capecitabine monotherapy in this setting. We hereby present a case report of using capecitabine monotherapy in first-line setting, and the patient had complete resolution of lung metastasis from the last 2 years. A 64-year-old postmenopausal lady with a known case of breast carcinoma in the left side diagnosed in the year 2016 with hormone receptor-positive, Her2-negative disease completed chemoradiation and on is aromatase inhibitor from the last 5 years. She complained of breathlessness and fatigue lasting for 1 month in July 2021. On evaluation, chest CT scan revealed multiple bilateral lung metastases along with 3×3 cm right-sided breast lump with no metastasis elsewhere in the body. Core needle biopsy of breast lump and CT-guided left lung nodule biopsy were performed which revealed infiltrating carcinoma with immunohistochemical markers showing tumor cells positive for Her-2-neu with hormone receptor-negative disease. PET-CT scan was done which revealed FDG avidity in bilateral lung fields and right breast lump with no disease elsewhere. Her echocardiography showed ejection fraction of 40% owing to which injection trastuzumab was deferred and the plan to start tablet capecitabine 1000 mg twice BD days 1-14 cycles every 21 days was made. She showed improvement in symptoms with PET-CT scan revealing resolution of lung metastasis from the last 2 years. Trastuzumab in combination with pertuzumab and taxane is the standard of care for metastatic breast carcinoma with hormone receptor-negative and Her2-positive disease. But in patients who are elderly, frail with severe cardiac dysfunction, trastuzumab-based regimen is contraindicated. No study demonstrated efficacy of capecitabine monotherapy in this subset of disease. More prospective studies are required to identify patients who can benefit from capecitabine monotherapy in first-line setting in this subset of disease. Also capecitabine usage has several advantages mainly low cost and availability in oral form, and patients can be followed up on OPD basis.

Redefining the Incidence and Profile of Fluoropyrimidine-Associated Cardiotoxicity in Cancer Patients: A Systematic Review and Meta-Analysis

Aim: The cardiac toxicity that occurs during administration of anti-tumor agents has attracted increasing concern. Fluoropyrimidines have been used for more than half a century, but their cardiotoxicity has not been well clarified. In this study, we aimed to assess the incidence and profile of fluoropyrimidine-associated cardiotoxicity (FAC) comprehensively based on literature data. Methods: A systematic literature search was performed using PubMed, Embase, Medline, Web of Science, and Cochrane library databases and clinical trials on studies investigating FAC. The main outcome was a pooled incidence of FAC, and the secondary outcome was specific treatment-related cardiac AEs. Random or fixed effects modeling was used for pooled meta-analyses according to the heterogeneity assessment. PROSPERO registration number: (CRD42021282155). Results: A total of 211 studies involving 63,186 patients were included, covering 31 countries or regions in the world. The pooled incidence of FAC, by meta-analytic, was 5.04% for all grades and 1.5% for grade 3 or higher. A total of 0.29% of patients died due to severe cardiotoxicities. More than 38 cardiac AEs were identified, with cardiac ischemia (2.24%) and arrhythmia (1.85%) being the most frequent. We further performed the subgroup analyses and meta-regression to explore the source of heterogeneity, and compare the cardiotoxicity among different study-level characteristics, finding that the incidence of FAC varied significantly among different publication decades, country/regions, and genders. Patients with esophagus cancer had the highest risk of FAC (10.53%), while breast cancer patients had the lowest (3.66%). The treatment attribute, regimen, and dosage were significantly related to FAC. When compared with chemotherapeutic drugs or targeted agents, such a risk was remarkably increased (χ2 = 10.15, p < 0.01; χ2 = 10.77, p < 0.01). The continuous 5-FU infusion for 3–5 consecutive days with a high dosage produced the highest FAC incidence (7.3%) compared with other low-dose administration patterns. Conclusions: Our study provides comprehensive global data on the incidence and profile of FAC. Different cancer types and treatment appear to have varying cardiotoxicities. Combination therapy, high cumulative dose, addition of anthracyclines, and pre-existing heart disease potentially increase the risk of FAC.

Treatment-Related Coronary Disorders of Fluoropyrimidine Administration: A Systematic Review and Meta-Analysis

Background: Coronary disorders are recognized as the most common manifestation of fluoropyrimidine-related cardiotoxicity in clinical practice. However, there are limited and conflicting data on the incidence and profiles of fluoropyrimidine-related coronary disorders. In this meta-analysis, we aimed to systematically assess the incidence of all-grade and grade 3 or higher fluoropyrimidine-related coronary disorders, and further explore the factors that influence its occurrence.

Methods: Studies reporting the fluoropyrimidine-related coronary disorders were retrieved from a systematic search of English literature in the PubMed, Web of Science, Medline, and Cochrane database from 1 Jan 2001, to 1 Jan 2022. The NIH assessment tool was used to evaluate the quality of each study. The data of basic study characteristics, treatment details, and results of coronary toxicities were extracted. According to the results of the heterogeneity test (I² and p-value statistic), a random-effect model or fixed-effect model was selected for the pooled analysis of the incidence of adverse coronary events. Subgroup analysis was conducted to further explore the risks influencing the occurrence of fluoropyrimidine-related coronary disorders. The stability and publication bias of our results were evaluated by sensitivity analysis and Egger test, respectively.

Results: A total of 63 studies were finally included in our pooled analysis, involving 25,577 patients. The pooled cumulative incidence of all-grade and grade 3 or higher coronary disorders was 2.75% (95% CI 1.89%–3.76%) and 1.00% (95% CI 0.62%–1.47%), respectively. The coronary disorders were most reported as myocardial ischemia (1.28%, 95% CI 0.42%–2.49%) and angina/chest pain (1.1%, 95% CI 0.54%–1.81%). Subgroup analysis revealed that studies in the female-only population seemed to have a lower incidence of fluoropyrimidine-related coronary disorders. The occurrence of adverse coronary events varied among different tumor types. Patients with esophageal cancer have the highest coronary toxicity (6.32%), while those with breast cancer have a relatively lower incidence (0.5%). Coronary disorders induced by 5-FU monotherapy are more frequent than that induced by capecitabine (3.31% vs. 1.21%, p < 0.01). Fluoropyrimidine combination therapy, whether combined with other chemotherapy drugs, targeted therapy drugs, or radiotherapy, significantly increased the incidence of coronary complications (p < 0.01).

Conclusion: This meta-analysis has defined the incidence of fluoropyrimidine-related coronary disorders and depicted its epidemiological profiles for the first time, which may provide a reference for clinical practice in cancer management.

Anti-HER2 therapy in metastatic breast cancer: many choices and future directions

Metastatic HER2 + breast cancer is an expanding area of drug development and research, with three new drugs approved in 2020 alone. While first-line therapy is well-established for metastatic HER2 + breast cancer, the standard of care for second-line therapy will likely be changing soon based on the results of the DESTINY-Breast03 trial. In the third-line setting, many options are available. Considerations in choosing between regimens in the third-line include resistance to trastuzumab, the presence of brain metastases, and tolerability. High rates of resistance exist in this setting particularly due to expression of p95, a truncated form of HER2 that constitutively activates downstream signaling pathways. We suggest a tyrosine kinase inhibitor (TKI)-based regimen because of the activity of TKIs in brain metastases and in p95-expressing tumors. Attempts to overcome resistance to anti-HER2 therapies with PI3K inhibitors, mTOR inhibitors, and CDK 4/6 inhibitors are an active area of research. In the future, biomarkers are needed to help predict which therapies patients may benefit from the most. We review the many new drugs in development, including those with novel mechanisms of action.

Breast Cancer, Version 3.2020, NCCN Clinical Practice Guidelines in Oncology

Several new systemic therapy options have become available for patients with metastatic breast cancer, which have led to improvements in survival. In addition to patient and clinical factors, the treatment selection primarily depends on the tumor biology (hormone-receptor status and HER2-status). The NCCN Guidelines specific to the workup and treatment of patients with recurrent/stage IV breast cancer are discussed in this article.

The Use of Immunotherapy to Treat Metastatic Breast Cancer

This article reviews the principal attempts of immune-modulation or immune therapy in metastatic breast cancer. It considers their rationale and reports on results from the relevant key clinical trials. Immune-modulatory or immune-stimulating cytokines used alone or combined with conventional therapies is among the principal approaches of immune manipulation in breast cancer. As this issue has recently been reviewed by us, the aim of the current article is to discuss our updated and unpublished data on this topic. Overall survival in luminal (28 patients) and non-luminal (9 patients) molecular subtypes is 91 and 59 months respectively that is about two and half or three times longer than expected. Thereafter, we focus on monoclonal antibodies (mAb) based-therapies including novel strategies to overcome resistance to anti-HER2 mAb. The main vaccine platforms in different molecular subtypes and immune therapies in triple negative metastatic breast cancer (m-TNBC) are discussed in the last sections. Some phase III investigations have already changed the current clinical practice. In fact, pertuzumab plus trastuzumab and docetaxel is the recommended first line regimen in HER2 positive locally recurrent or metastatic breast cancer and bevacizumab plus paclitaxel or docetaxel is a reasonable option for m-TNBC. In some other observational or phase I/II studies on first-line trastuzumab plus chemotherapy and hormonal therapy and in that on HER2 peptide/protein vaccines promising although preliminary findings have been reported to be further validated. In the remaining studies, results were disappointing. In the future, finding new predictive biomarkers and exploring more suitable synergizing combinations, time and dose-dependent-scheduled sequences of currently and further investigated immunological approaches are main challenges.

Clinical effects of prior trastuzumab on combination eribulin mesylate plus trastuzumab as first-line treatment for human epidermal growth factor receptor 2 positive locally recurrent or metastatic breast cancer: results from a Phase II, single-arm, multicenter study

Eribulin mesylate, a novel nontaxane microtubule dynamics inhibitor in the halichondrin class of antineoplastic drugs, is indicated for the treatment of patients with metastatic breast cancer who previously received ≥2 chemotherapy regimens in the metastatic setting. Primary data from a Phase II trial for the first-line combination of eribulin plus trastuzumab in human epidermal growth factor receptor 2 positive patients showed a 71% objective response rate and tolerability consistent with the known profile of these agents. Here, we present prespecified analyses of efficacy of this combination based on prior trastuzumab use. Patients received eribulin mesylate 1.4 mg/m² (equivalent to 1.23 mg/m² eribulin [expressed as free base]) intravenously on days 1 and 8 plus trastuzumab (8 mg/kg intravenously/cycle 1, then 6 mg/kg) on day 1 of each 21-day cycle. Objective response rates, progression-free survival, and tolerability were assessed in patients who had and had not received prior adjuvant or neoadjuvant (neo/adjuvant) trastuzumab treatment. Fifty-two patients (median age: 59.5 years) received eribulin/trastuzumab for a median treatment duration of ~31 weeks; 40.4% (n=21) had been previously treated with neo/adjuvant trastuzumab prior to treatment with eribulin plus trastuzumab for metastatic disease (median time between neo/adjuvant and study treatment: 23 months). In trastuzumab-naïve patients (n=31) compared with those who had received prior trastuzumab, objective response rate was 77.4% versus 61.9%, respectively; duration of response was 11.8 versus 9.5 months, respectively; clinical benefit rate was 87.1% versus 81.0%, respectively; and median progression-free survival was 12.2 versus 11.5 months, respectively. The most common grade 3/4 treatment-emergent adverse events (occuring in ≥5% of patients) in patients who received prior trastuzumab versus trastuzumab naïve patients, respectively, were neutropenia (47.6% vs 32.3%), peripheral neuropathy (14.3% vs 25.8%), febrile neutropenia (14.3% vs 3.2%), fatigue (9.5% vs 6.5%), nausea (9.5% vs 0%), vomiting (9.5% vs 3.2%), and leukopenia (9.5% vs 3.2%). In patients with human epidermal growth factor receptor 2 positive metastatic breast cancer, first-line eribulin/trastuzumab treatment demonstrated substantial antitumor activity and was well tolerated, regardless of prior neo/adjuvant trastuzumab treatment.

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.

Phase 1B/2 study of the HSP90 inhibitor AUY922 plus trastuzumab in metastatic HER2-positive breast cancer patients who have progressed on trastuzumab-based regimen

This open-label, multicenter, phase 1B/2 trial assessed AUY922 plus trastuzumab in patients with locally advanced or metastatic HER2-positive breast cancer previously treated with chemotherapy and anti-HER2 therapy. This study was composed of a dose-escalation part with AUY922 administered weekly at escalating doses with trastuzumab 2 mg/kg/week (phase 1B), followed by a phase 2 part using the same regimen at recommended phase 2 dose (RP2D). The primary objectives were to determine the maximum tolerated dose (MTD) and/or RP2D (phase 1B), and to evaluate preliminary antitumor activity (phase 2) of AUY922 plus trastuzumab at MTD/RP2D. Forty-five patients were treated with AUY922 plus trastuzumab (4 in phase 1B with AUY922 at 55 mg/m2 and 41 in phase 1B/2 with AUY922 at 70 mg/m2 [7 in phase 1B and 34 in phase 2]). One patient in phase 1B (70 mg/m2) experienced a dose-limiting toxicity (grade 3 diarrhea); the RP2D was weekly AUY922 70 mg/m2 plus trastuzumab. Of the 41 patients in the 70 mg/m2 cohort, the overall response rate (complete or partial responses) was 22.0% and 48.8% patients had stable disease. Study treatment-related adverse events occurred in 97.8% of patients; of these, 31.1% were grade 3 or 4. Forty-one patients (91.1%) reported ocular events (82.3% had grade 1 or 2 events). Two patients (4.4%) had ocular events leading to the permanent discontinuation of study treatment. AUY922 at 70 mg/m2 plus trastuzumab standard therapy is well tolerated and active in patients with HER2-positive metastatic breast cancer who progressed on trastuzumab-based therapy.

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

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

Randomized study of orally administered fluorinated pyrimidines (capecitabine versus S-1) in women with metastatic or recurrent breast cancer: Japan Breast Cancer Research Network 05 Trial

PURPOSE

Capecitabine and S-1 are orally administered fluorinated pyrimidines with high-level activity against metastatic breast cancer (MBC). This randomized, multicenter, phase II study compared the activities and safeties of the oral fluoropyrimidines, capecitabine and S-1, in breast cancer patients.

METHODS

Patients with MBC were randomly assigned to receive capecitabine 825 g/m(2) twice daily on days 1-21 every 4 weeks or S-1 40-60 mg twice daily, according to body surface area, on days 1-28 every 6 weeks. The primary endpoint was progression-free survival (PFS).

RESULTS

A total of 142 patients were enrolled and randomized to either capecitabine (N = 73) or S-1 (N = 69). Median PFS (progression-free survival) was 1.2 years for capecitabine and 1.3 years for S-1, with a hazard ratio (S-1/capecitabine) of 0.85 (95 % confidence interval [CI] 0.52-1.38) (P = 0.48 by log-rank). The confirmed objective response rates were 24.0 % for capecitabine and 23.1 % for S-1 (P = 0.938). The most common treatment-related adverse events were grade 1-2 in intensity. Thrombocytopenia (S-1: 9.2 %, capecitabine: 1.4 %; P = 0.040) and nausea (S-1: 26.2 %, capecitabine: 14.1 %; P = 0.079) were more frequent in the S-1 group, while hand-foot syndrome occurred more often in the capecitabine group (S-1: 10.8 %, capecitabine: 25.4 %; P = 0.029).

CONCLUSIONS

The results of the current study demonstrate that both S-1 and capecitabine are effective and well-tolerated treatments in patients with MBC, while their adverse events were different. They are both convenient, orally administered drugs, making them attractive agents for use in outpatient treatment.

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

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

Treatment of HER2-positive breast cancer

The human epidermal growth factor receptor 2 gene (HER2) is overexpressed and/or amplified in ~15% of breast cancer patients and was identified a quarter century ago as a marker of poor prognosis. By 1998, antibody therapy targeting the HER2 pathway was shown to demonstrably improve progression-free and overall survival in metastatic disease, and in 2005 evidence of improvement in disease-free and overall survival from the first generation of trastuzumab adjuvant trials became available. However, not all patients with HER2 overexpression benefit from trastuzumab. Second-generation studies in metastatic disease led to the approval of several new HER2-targeted therapies using small molecule tyrosine kinase inhibitors such as lapatinib, new HER2/HER3 antibodies such as pertuzumab, and the new antibody chemotherapy conjugate ado-trastuzumab emtansine. These successes supported the launch of second-generation adjuvant trials testing single and dual HER2-targeted agents, administered concomitantly or sequentially with chemotherapy that will soon complete accrual. HER2-positive breast cancer in the setting of HER2-targeted therapy is no longer associated with poor prognosis, and recent guidance by the US Food and Drug Administration suggests that pathologic response to HER2-targeted therapy given preoperatively may allow an earlier assessment of their clinical benefit in the adjuvant setting. An adjuvant trial of trastuzumab in patient whose tumors express normal levels of HER2 and trials of single/dual HER2-targeting without chemotherapy are also ongoing. In this article, we review the current data on the therapeutic management of HER2-positive breast cancer.

Targeted therapy in HER2-positive breast cancer

Treatment options for breast cancer vary based on tumor surface markers and clinical factors, including cytotoxic chemotherapy, hormonal therapy, biological therapy or a combination thereof. An important molecular determinant of therapy is the human epidermal growth factor receptor 2 (HER2) positivity of the tumor, which has been identified in 20-25% of breast cancers and is a prognostic marker of poor outcome. The advent of HER2-targeted therapies has significantly improved the survival of patients with HER2-positive breast cancer. This review focuses on current HER2-targeted therapeutic options for patients with HER2-positive breast cancer, including monoclonal antibodies and tyrosine kinase inhibitors (TKIs).

Recent advances in novel targeted therapies for HER2-positive breast cancer

The monoclonal antibody trastuzumab has improved the outcomes of patients with breast cancer that overexpresses the human epidermal growth factor receptor 2 (HER2). However, despite this advancement, many tumors develop resistance and novel approaches are needed. Recently, a greater understanding of cellular biology has translated into the development of novel anti-HER2 agents with varying mechanisms of action. The small molecule tyrosine kinase inhibitor lapatinib has demonstrated activity in HER2-positive metastatic breast cancer (MBC) and in the preoperative setting. Pertuzumab is a monoclonal antibody with a distinct binding site from trastuzumab, which inhibits receptor dimerization. In recent studies, the addition of pertuzumab to combination therapy has led to improvements in progression-free survival in patients with HER2-positive MBC and higher response rates in the preoperative setting. An alternative approach is the use of novel antibody-drug conjugates such as trastuzumab-emtansine, which recently demonstrated activity in MBC. Neratinib, a pan-HER tyrosine kinase inhibitor, which irreversibly inhibits HER1 and HER2, also has proven activity in MBC. A range of compounds is being developed to attempt to overcome trastuzumab resistance by targeting heat shock protein 90, a molecular chaperone required for the stabilization of cellular proteins. Furthermore, agents are being developed to inhibit the mammalian target of rapamycin, a downstream component of the PTEN/PI3K pathway, which has been implicated in trastuzumab resistance. Finally, there are emerging data indicating that combinations of anti-HER2 agents may circumvent resistance mechanisms and improve patient outcomes. In this review, recent data on these emerging agents and novel combinations for HER2-positive breast cancer are discussed.

Phase II study of bevacizumab in combination with trastuzumab and capecitabine as first-line treatment for HER-2-positive locally recurrent or metastatic breast cancer

We report the first results from a phase II, open-label study designed to evaluate the efficacy and safety of bevacizumab in combination with trastuzumab and capecitabine as first-line therapy for human epidermal growth factor receptor (HER)-2-positive locally recurrent (LR) or metastatic breast cancer (MBC). Patients were aged ≥18 years with confirmed breast adenocarcinoma, measurable LR/MBC and documented HER-2-positive disease. Patients received bevacizumab (15 mg/kg on day 1) plus trastuzumab (8 mg/kg on day 1 of cycle 1, 6 mg/kg on day 1 of each subsequent cycle) plus capecitabine (1,000 mg/m2 twice daily, days 1-14) every 3 weeks until disease progression, unacceptable toxicity, or consent withdrawal. Eighty-eight patients were enrolled; 40 (46%) are still on study treatment. The median follow-up was 8.8 months (range, 0.9-17.1 months). The overall response rate, the primary endpoint, was 73% (95% confidence interval [CI], 62%-82%), comprising 7% complete and 66% partial responses. The median progression-free survival interval was 14.4 months (95% CI, 10.4 months to not reached [NR]), with 35 events. The median time to progression was 14.5 months (95% CI, 10.5 months to NR), with 33 events. Treatment was well tolerated; main side effects were grade 3 hand-foot syndrome (22%), grade ≥3 diarrhea (9%), and grade ≥3 hypertension (7%). Overall, 44% of patients experienced grade ≥3 treatment-related adverse events and 13 patients discontinued capecitabine because of toxicity, but continued with bevacizumab and trastuzumab. Heart failure was seen in two patients. The combination of bevacizumab, trastuzumab, and capecitabine was clinically active as first-line therapy for patients with HER-2-positive MBC, with an acceptable safety profile and no unexpected toxicities.

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.

Post-marketing safety evaluation of S-1 in patients with inoperable or recurrent breast cancer: especially in patients treated with S-1 + trastuzumab

Objective

The purpose of this study was to assess the safety of S-1 in Japanese in inoperable or recurrent breast cancer patients.

Methods

A prospective post-marketing surveillance was performed at 313 sites in Japan in patients with inoperable or recurrent breast cancer treated with S-1. We examined 1361 patients between January 2006 and December 2007 with regard to the incidence of adverse drug reactions graded by the Common Terminology Criteria for Adverse Events (CTCAE), version 3.0.

Results

At least one adverse drug reaction was encountered by 858 patients, with an overall incidence of 63.0% (858/1361). The incidence of Grade 3 or higher adverse drug reactions in a descending order was 14.7% (200/1361). In this study, the most common combination drug was trastuzumab. The overall incidence of adverse drug reactions was 63.5% (431/679 patients) in patients treated with S-1 alone, and 55.9% (66/118 patients) in patients treated with S-1 + trastuzumab.

Conclusions

Monotherapy with S-1 or combination therapy with S-1 + trastuzumab was well tolerated for inoperable or recurrent breast cancer patients.

Randomized phase II trial of first-line trastuzumab plus docetaxel and capecitabine compared with trastuzumab plus docetaxel in HER2-positive metastatic breast cancer

PURPOSE To evaluate trastuzumab (H) and docetaxel (T) with or without capecitabine (X) as first-line combination therapy for human epidermal growth factor receptor 2 (HER2) -positive advanced breast cancer. PATIENTS AND METHODS Patients with HER2-positive locally advanced or metastatic breast cancer were randomly assigned to H (8 mg/kg loading; 6 mg/kg every 3 weeks) plus T (75 mg/m(2) in HTX arm, 100 mg/m(2) in HT arm, every 3 weeks) with or without X (950 mg/m(2) twice per day on days 1 to 14 every 3 weeks). The primary end point was overall response rate (ORR). Results In 222 patients, median follow-up was approximately 24 months. ORR was high with both regimens (70.5% with HTX; 72.7% with HT; P = .717); complete response rate was 23.2% with HTX compared with 16.4% with HT. HTX demonstrated significantly longer progression-free survival: median 17.9 months compared with 12.8 months with HT (hazard ratio, 0.72; P = .045), which translates to a gain of around 5 months. Two-year survival probability was 75% with HTX compared with 66% with HT. Febrile neutropenia (27% v 15%) and grade 3/4 neutropenia (77% v 54%) incidences were higher with HT than HTX. Treatment-related grade 3 hand-foot syndrome (17% v < 1%) and grade 3/4 diarrhea (11% v 4%) occurred more commonly with HTX than HT. One case of congestive heart failure occurred in each arm. CONCLUSION HTX is an effective and feasible first-line therapy for HER2-positive locally advanced or metastatic breast cancer, although it should be reserved for patients with good performance status who are not receiving long-term steroids.

First-line chemotherapy for metastatic breast cancer

The selection of first-line chemotherapy for metastatic breast cancer (MBC) is complex because of the myriad of treatment options available and the inherent biologic heterogeneity of the disease. The potential treatment options are greatly influenced by estrogen and progesterone receptor and HER2 status of the tumor, and biopsy with reassessment of these markers at the time of disease recurrence is strongly recommended. Metastatic breast cancer is generally an incurable disease, with survival that could range from months to several years. Important but modest improvements in overall survival (OS) have been observed for women with MBC over the past few decades, in part because of improvements in systemic therapy. For women with endocrine-responsive disease, hormonal therapy is the appropriate initial treatment choice at the time of disease recurrence with rare exception. Initiation of systemic chemotherapy is appropriate for women with disease that is either hormone receptor negative, endocrine therapy refractory, or rapidly progressive with visceral involvement. The addition of trastuzumab to chemotherapy for women with HER2-positive breast cancer represents a clear standard of care. For HER2-negative MBC, sequential single-agent chemotherapy is preferred over combination therapy as a result of the more favorable toxicity profile and absence of a clinically significant improvement in survival with combination treatment. Many single-agent chemotherapeutic agents have activity in MBC, with most data supporting an anthracycline- or taxane-based approach. Bevacizumab in combination with chemotherapy prolongs progression-free survival in women with MBC, though its position in the first-line treatment of MBC relative to standard chemotherapy remains unclear at this time because of lack of OS benefit.

Concurrent trastuzumab and HER2/neu-specific vaccination in patients with metastatic breast cancer

PURPOSE

The primary objectives of this phase I/II study were to evaluate the safety and immunogenicity of combination therapy consisting of concurrent trastuzumab and human epidermal growth factor receptor 2 (HER2)/neu-specific vaccination in patients with HER2/neu-overexpressing metastatic breast cancer.

PATIENTS AND METHODS

Twenty-two patients with stage IV HER2/neu-positive breast cancer receiving trastuzumab therapy were vaccinated with an HER2/neu T-helper peptide-based vaccine. Toxicity was graded according to National Cancer Institute criteria, and antigen specific T-cell immunity was assessed by interferon gamma enzyme-linked immunosorbent spot assay. Data on progression-free and overall survival were collected.

RESULTS

Concurrent trastuzumab and HER2/neu vaccinations were well tolerated, with 15% of patients experiencing an asymptomatic decline in left ventricular ejection fraction below the normal range during combination therapy. Although many patients had pre-existing immunity specific for HER2/neu and other breast cancer antigens while treated with trastuzumab alone, that immunity could be significantly boosted and maintained with vaccination. Epitope spreading within HER2/neu and to additional tumor-related proteins was stimulated by immunization, and the magnitude of the T-cell response generated was significantly inversely correlated with serum transforming growth factor beta levels. At a median follow-up of 36 months from the first vaccine, the median overall survival in the study population has not been reached.

CONCLUSION

Combination therapy with trastuzumab and a HER2/neu vaccine is associated with minimal toxicity and results in prolonged, robust, antigen-specific immune responses in treated patients.

Contemporary issues and the potential uses of capecitabine in metastatic breast cancer

Since its first regulatory approval more than 10 years ago, oncologists have gained wide experience in using the oral fluoropyrimidine, capecitabine, as monotherapy or in combination with other agents and the body of evidence supporting these approaches continues to grow. Alongside this increasing experience has been the appearance of new challenges in patient management. We now recognise several different biological subtypes of breast cancer, such as HER2-positive disease. The standard of care in these tumours comprises anti-HER2 therapy, and phase III data show that capecitabine can be effectively combined with such agents. Another increasingly prominent and currently unresolved issue resulting from more effective treatment of metastatic disease is the management of patients with brain metastases. The introduction of new, well-tolerated, oral chemotherapies also provides the opportunity for longer duration of therapy. These new clinical scenarios are discussed in the current review.

Pharmacology and therapeutic efficacy of capecitabine: focus on breast and colorectal cancer

Capecitabine (N -pentyloxycarbonyl-5-deoxy-5-fluorocytidine), an oral prodrug of 5-fluorouracil, has provided compelling efficacy data for the treatment of metastatic breast cancer and stage III or IV colorectal cancer, both as monotherapy and in combination regimens. The preferential conversion of capecitabine to 5-fluorouracil in neoplastic tissues renders this fluoropyrimidine particularly appealing for clinical use. The enzyme thymidine phosphorylase, which mediates the final step of the capecitabine activation pathway, is expressed in higher concentration in neoplastic than in healthy tissues. This makes capecitabine more tumor specific than other chemotherapeutic agents. Accordingly, capecitabine is generally well tolerated. In particular, the incidence of myelosuppression and alopecia is low, and the most common side effects, hand-foot syndrome and diarrhea, are usually manageable. Given its good toxicity profile, capecitabine was assessed in combination with several chemotherapeutic or biologic agents. In addition, the observation that thymidine phosphorylase is upregulated after treatment with other anticancer drugs, namely taxanes, provided a rationale for the prominent antitumor activity recently observed for the combination of capecitabine with these agents. This review provides an evidence-based update of clinical trials investigating the role of capecitabine in the treatment of breast and colorectal cancer, with special emphasis on pharmacological and safety issues that form the basis of currently used schedules.

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.

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.

Predictive factors for efficacy of capecitabine in heavily pretreated patients with metastatic breast cancer

PURPOSE

The purpose of the present study is to evaluate what clinical factors affect the efficacy, time to treatment failure (TTF), and overall survival (OS) of oral capecitabine monotherapy in heavily pretreated patients with metastatic breast cancer (MBC).

METHODS

A total of 102 consecutive patients with MBC who had been administered capecitabine monotherapy between June 2003 and August 2004 were retrospectively reviewed. Capecitabine (828 mg/m(2)) was given twice daily for 3 weeks followed by a 1-week rest period; this was repeated every 4 weeks. We evaluated the potential clinical factors for TTF and OS, using univariate analysis (log-rank test) and the multivariate Cox regression model. Median follow-up was 16.9 months.

RESULTS

A total of 100 patients (98%) had been pretreated with either anthracyclines or taxanes, and 81 patients (79%) with both anthracyclines and taxanes. Response rate was 17% and clinical benefit rate was 41%. Median TTF and OS were 4.9 and 24.3 months, respectively. Multivariate analysis demonstrated that no liver metastasis (P = 0.015), good performance status (P = 0.033), longer disease-free interval (P = 0.036), and hormone receptor-positive tumor (P = 0.038) were significant for TTF. No liver metastasis (P = 0.00012), objective response to capecitabine (P = 0.00084), and good performance status (P = 0.0011) were significant for OS.

CONCLUSIONS

Capecitabine monotherapy is effective over the long term for heavily pretreated patients with MBC who have no liver metastasis, good performance status, longer disease-free interval, or hormone receptor-positive tumor. Patients who have no liver metastasis, who respond to capecitabine, or who have good performance status are expected to survive even longer.

XeNA: capecitabine plus docetaxel, with or without trastuzumab, as preoperative therapy for early breast cancer

Combinations of capecitabine and a taxane are highly active in metastatic breast cancer, and synergy between capecitabine and docetaxel has also been demonstrated. Such combinations potentially would provide a promising non-anthracycline-based alternative for patients with early breast cancer. Non-anthracycline preoperative regimens are a particularly interesting proposition in human epidermal growth factor receptor 2 (HER2)-positive breast cancer, as they offer less cardiotoxicity and thus can be used concomitantly with preoperative trastuzumab therapy. Capecitabine plus docetaxel (XT) and trastuzumab with XT (HXT) are promising non-anthracycline regimens for the preoperative treatment of women with HER2-negative and HER2-positive breast cancer, respectively. The Xeloda in Neoadjuvant (XeNA) trial, an open-label, multicenter, phase II study, independently assesses the efficacy of preoperative XT in HER2-negative and HXT in HER2-positive breast cancer. A particularly important feature of the XeNA study is the use of pathologic complete response (pCR) plus near pCR (npCR) as the primary endpoint. pCR is associated with long-term survival, and although it is valuable as a surrogate marker, pCR has some limitations. Measurement of residual breast cancer burden (RCB) has been proposed as a more practical alternative to predict survival after preoperative chemotherapy. The combination of RCB-0 and RCB-I (npCR) expands the subset of patients shown to benefit from preoperative chemotherapy, and achievement of pCR or npCR is associated with long disease-free survival. In XeNA, the sum of pCR and npCR will facilitate correlative studies designed to identify patients most likely to benefit from XT and HXT and may expedite the clinical evaluation of these novel preoperative regimens.