Phase II study of capecitabine and trastuzumab combination chemotherapy in patients with HER2 overexpressing metastatic breast cancers resistant to both anthracyclines and taxanes

Role of Molecular Targeted Therapeutic Drugs in Treatment of Breast Cancer: A Review Article

Breast cancer is a multifactor, multistage, and heterogeneous disease. Systemic treatment of breast cancer has changed significantly over the last decade. With a better knowledge of the pathogenesis, researchers and scientists have discovered numerous signaling pathways and synonymous therapeutic targets in breast cancer. Because of the molecular nature of breast cancer, which makes it difficult to understand, previous attempts to treat or prevent it have failed. However, recent decades have provided effective therapeutic targets for treatment. In this review, literature or information on various targeted therapy for breast cancer is discussed. English language articles were explored in numerous directory or databases like PubMed, Web of Sciences, Google Scholar, ScienceDirect, and Scopus. The important keywords used for searching databases are "Breast cancer," "Targeted therapy in breast cancer," "Therapeutic drugs in breast cancer," and "Molecular targets in breast cancer."

Cardiac metastasis after esophagogastrectomy for esophageal adenocarcinoma with an antemortem diagnosis

Cardiac metastasis is uncommon and rarely diagnosed antemortem. Here, we describe a case of symptomatic cardiac metastasis from esophageal adenocarcinoma. A 64-year-old man developed chest symptoms 26 months after curative esophagogastrectomy for esophageal adenocarcinoma. Initially, ischemic cardiac disease was suspected based on electrocardiography findings, but an infiltrative tumor was seen morphologically in the wall of the interventricular septum and apex. No other lesions were detected. Histological examination of a transcatheter biopsy specimen indicated that the cardiac tumor was metastasis from esophageal adenocarcinoma. Chemoradiotherapy with cisplatin relieved his symptoms, and he had resumed normal activities. However, he opted not to undergo further aggressive treatment due to severe adverse effects from cisplatin. Seventeen months after completion of chemoradiotherapy, metastases to the right ventricle and the left thighbone were detected and he died 27 and 24 months after the diagnosis of cardiac metastasis and completion of chemoradiotherapy, respectively.

Capecitabine in Combination with Endocrine Therapy as Maintenance Therapy after Bevacizumab Plus Paclitaxel Induction Therapy for Hormone Receptor-Positive, HER2-Negative Metastatic Breast Cancer: KBCSG-TR1214

Simple Summary

To investigate a possible treatment strategy for hormone receptor (HR)-positive, HER2-negative advanced and/or metastatic breast cancer (AMBC), we investigated the clinical usefulness of adding capecitabine to maintenance endocrine therapy after induction chemotherapy and the efficacy of reinduction chemotherapy. Patients who had received bevacizumab–paclitaxel induction therapy and did not have progressive disease were randomized to receive maintenance therapy with endocrine therapy alone (group E; n = 46) or endocrine therapy plus capecitabine (group EC; n = 44). The median progression-free survival (PFS) under maintenance therapy (primary endpoint) was significantly longer in group EC than in group E (11.1 vs. 4.3 months; hazard ratio, 0.53; p < 0.01). At 24 months from the induction therapy start, the overall survival (OS) rate was significantly higher in group EC than in group E (83.5% vs. 62.3%; p = 0.02). Therefore, the addition of capecitabine to maintenance endocrine therapy may be a beneficial option after induction chemotherapy for HR-positive, HER2-negative AMBC patients.

Abstract

Optimal treatment strategies for hormone receptor (HR)-positive, HER2-negative advanced and/or metastatic breast cancer (AMBC) remain uncertain. We investigated the clinical usefulness of adding capecitabine to maintenance endocrine therapy after induction chemotherapy and the efficacy of reinduction chemotherapy. Patients who had received bevacizumab–paclitaxel induction therapy and did not have progressive disease (PD) were randomized to maintenance therapy with endocrine therapy alone (group E) or endocrine plus capecitabine (1657 mg/m²/day on days 1–21, q4w) (group EC). In case of PD after maintenance therapy, patients received bevacizumab–paclitaxel reinduction therapy. Ninety patients were randomized. The median progression-free survival (PFS) under maintenance therapy (primary endpoint) was significantly longer in group EC (11.1 {95% CI, 8.0–11.8} months) than in group E (4.3 {3.6–6.0} months) (hazard ratio, 0.53; p < 0.01). At 24 months from the induction therapy start, the overall survival (OS) was significantly longer in group EC than in group E (hazard ratio, 0.41; p = 0.046). No difference was found in the time to failure of strategy (13.9 and 16.6 months in groups E and EC, respectively). Increased capecitabine-associated toxicities in group EC were tolerable. Addition of capecitabine to maintenance endocrine therapy may be a beneficial option after induction chemotherapy for HR-positive, HER2-negative AMBC patients.

Efficacy and Safety of Trastuzumab Emtansine Plus Capecitabine vs Trastuzumab Emtansine Alone in Patients With Previously Treated ERBB2 (HER2)-Positive Metastatic Breast Cancer: A Phase 1 and Randomized Phase 2 Trial

Importance

ERBB2 (HER2)-targeted therapy provides benefits in metastatic breast cancer (mBC) and gastric cancer, but additional treatments are needed to maximize efficacy and quality of life.

Objective

To determine maximum tolerated doses (MTDs) of trastuzumab emtansine (T-DM1) plus capecitabine in patients with previously treated ERBB2-positive mBC and locally advanced/metastatic gastric cancer (LA/mGC) (phase 1) and the efficacy and safety of this combination vs T-DM1 alone in patients with mBC (phase 2).

Design, Setting, and Participants

The MTD in phase 1 was assessed using a 3 + 3 design with capecitabine dose modification. Phase 2 was an open-label, randomized, international multicenter study of patients with mBC treated with T-DM1 plus capecitabine or T-DM1 alone. Eligible patients had previously treated ERBB2-positive mBC or LA/mGC with no prior chemotherapy treatment for advanced disease.

Interventions

Patients in the phase 1 mBC cohort received capecitabine (750 mg/m2, 700 mg/m2, or 650 mg/m2 twice daily, days 1-14 of a 3-week cycle) plus T-DM1 3.6 mg/kg every 3 weeks. Patients with LA/mGC received capecitabine at the mBC phase 1 MTD, de-escalating as needed, plus T-DM1 2.4 mg/kg weekly. In phase 2, patients with mBC were randomized (1:1) to receive capecitabine (at the phase 1 MTD) plus T-DM1 or T-DM1 alone.

Main Outcomes and Measures

The phase 1 primary objective was to identify the MTD of capecitabine plus T-DM1. The phase 2 primary outcome was investigator-assessed overall response rate (ORR).

Results

In phase 1, the median (range) age was 54.0 (37-71) and 57.5 (53-70) years for patients with mBC and patients with LA/mGC, respectively. The capecitabine MTD was identified as 700 mg/m2 in 11 patients with mBC and 6 patients with LA/mGC evaluable for dose-limiting toxic effects. In phase 2, between October 2014 and April 2016, patients with mBC (median [range] age, 52.0 [28-80] years) were randomized to receive combination therapy (n = 81) or T-DM1 (n = 80). The ORR was 44% (36 of 81 patients) and 36% (29 of 80 patients) in the combination and T-DM1 groups, respectively (difference, 8.2%; 90% CI, -4.5 to 20.9; P = .34; clinical cutoff, May 31, 2017). Adverse events (AEs) were reported in 78 of 82 patients (95%) in the combination group, with 36 (44%) experiencing grade 3-4 AEs, and 69 of 78 patients (88%) in the T-DM1 group, with 32 (41%) experiencing grade 3-4 AEs. No grade 5 AEs were reported.

Conclusions and Relevance

Adding capecitabine to T-DM1 did not statistically increase ORR associated with T-DM1 in patients with previously treated ERBB2-positive mBC. The combination group reported more AEs, but with no unexpected toxic effects.

Trial Registration

ClinicalTrials.gov Identifier: NCT01702558.

Pharmacotherapeutics of capecitabine and trastuzumab in the treatment of metastatic breast cancer

Metastatic HER2-positive breast cancer is an incurable disease with a poor prognosis. This article presents a critical appraisal of two treatments commonly used in the treatment of metastatic HER2-positive breast cancer: the oral chemotherapy drug, capecitabine, and the monoclonal antibody, trastuzumab. What follows is a critical discussion of the pharmacotherapeutics of capecitabine and trastuzumab, which considers their use both as single agents and as a combination regimen in the treatment of metastatic breast cancer. The implications of side effects of these drugs are discussed, both individually and in combination, as are the challenges these bring to the prescriber. The article evaluates the use of these agents and concludes that the combination of capecitabine and trastuzumab is an attractive treatment option for patients and for the prescriber.

Perspectives on the mechanism of action and clinical application of eribulin for metastatic breast cancer

Eribulin is a novel microtubule inhibitor with mitotic and nonmitotic mechanisms of action. Both pooled and subgroup analyses from large-scale Phase III clinical trials demonstrated that eribulin has substantial activity in patients with pretreated (anthracycline and a taxane) advanced or metastatic breast cancer. We review recent pharmacological and clinical findings pertaining to eribulin use in metastatic breast cancer – particularly highlighting eribulin in difficult-to-treat and aggressive disease, and safety data in specific patient populations. Additionally, recent advancements in our understanding of the mechanism of action of eribulin and potential future directions for its clinical development are discussed. Ongoing studies of eribulin in combination with immunotherapies and established cytotoxic agents may help shape the future landscape of breast cancer treatment.

Trastuzumab Emtansine (T-DM1) Plus S-1 in Patients with Trastuzumab-Pretreated HER2-Positive Advanced or Metastatic Breast Cancer: A Phase Ib Study

BACKGROUND

In treating human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer, the efficacy of capecitabine combined with HER2-directed agents such as trastuzumab and lapatinib is supported by some evidence. The combination of T-DM1 and S-1, another oral 5-FU, may be a safe alternative treatment for metastatic breast cancer.

OBJECTIVES

The optimal dose of S-1 was evaluated in combination with T-DM1 for patients with HER2-positive advanced or metastatic breast cancer. The safety and clinical response of this combination treatment were also assessed.

METHODS

This 3 + 3 dose-escalation study of S-1 given for the first 2 of 3 weeks, in combination with T-DM1 (3.6 mg/kg given every 3 weeks) to patients with trastuzumab-pretreated HER2-positive advanced or metastatic breast cancer was designed to evaluate the dose-limiting toxicity (DLT) occurrence in the first cycle. We also evaluated the safety and clinical activity of this combination treatment in multiple cycles. Two different dose levels of S-1 (65 and 80 mg/m2/day) were planned, although the capecitabine arm was abandoned because of slow recruitment.

RESULTS

Twelve out of the 13 patients enrolled were evaluable for DLT. One DLT (grade ≥3 non-hematological adverse events) occurred at dose level 0, leading to the expansion of this cohort to 6 patients, with an additional DLT (≥7 days discontinuation of medication), while no DLT occurred at dose level 1. As a result, the maximum tolerable dose of S-1 was determined to be 80 mg/m2/day for 14 days with T-DM1 3.6 mg/kg, repeated every 3 weeks. Two patients had grade 3 thrombocytopenia at dose level 0, and 1 patient at dose level 1.

CONCLUSIONS

S-1 can be safely combined with the clinically relevant dose of T-DM1 in patients with HER2-positive advanced or metastatic breast cancer. Further evaluation with a larger sample size is required for efficacy assessment.

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.

NRBP1 is downregulated in breast cancer and NRBP1 overexpression inhibits cancer cell proliferation through Wnt/β-catenin signaling pathway

Nuclear receptor binding protein 1 (NRBP1) is a highly conserved protein that is ubiquitously expressed across cell types in humans. NRBP1 has been recently identified as an adaptor protein. It has been suggested that it plays important roles in cellular homeostasis and the pathophysiology of cancer. To determine whether NRBP1 is involved in the pathophysiology of breast cancer, we performed a correlation study between the expression level of NRBP1 and the clinicopathological features in 92 breast cancer patients. A strong correlation was detected between NRBP1 expression and advanced histopathology grades, tumor, node, and metastasis stage, tumor diameter, lymph node involvement, as well as the recurrence of breast cancer in 92 tested patients. The tumor tissues from patients also expressed lower NRBP1 than did adjacent healthy tissues. Furthermore, we overexpressed NRBP1 in MCF-7 and MDA-MB-231 breast cancer cell lines and found NRBP1 upregulation-inhibited cell proliferation by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Blocking the autocrine Wnt signaling pathway by LGK974 could remove the NRBP1-overexpression-induced inhibition in breast cancer cells. The results of this study suggest that NRBP1 plays a tumor-suppressive role in breast cancer pathophysiology, which likely acts through the Wnt/β-catenin signaling pathway.

Examination of the clinical efficacy of eribulin and trastuzumab in HER2-positive recurrent breast cancer

There are limited studies reported that describe the efficacy of eribulin and trastuzumab in the treatment of recurrent breast cancer. The present study examined the therapeutic efficacy of eribulin and trastuzumab in the treatment of recurrent breast cancer. Between October 2011 and August 2013, 5 recurrent breast cancer patients who were treated with eribulin and trastuzumab were included in the study. The cancer stages in the 5 women who received this regimen were stage IIIB in 1 (20%) and stage IV in 4 (80%). The sites of recurrence were the lung in 3 patients, liver in 2, bone in 1, brain in 1, supraclavicular lymph nodes in 1, infraclavicular lymph nodes in 1 and mediastinal lymph nodes in 1. The median number of prior treatment regimens was 5 (range, 5-11). Complete response was achieved in 0 patients, 1 achieved partial response, 3 had stable disease, and 1 had progressive disease. The overall response rate was 20%, and the clinical benefit rate was 80%. Patients also reported grade 3/4 neutropenia (80.0%). However, hematological toxicity was reversible and manageable. The most common grade 3/4 nonhematological toxicities were fatigue (20.0%), peripheral neuropathy (20.0%) and appetite loss (20.0%). No patients withdrew from treatment, and favorable compliance was achieved in the study. The results indicated that eribulin and trastuzumab have the potential to be one of the drugs for treatment of recurrent breast cancer.

Pathological response rate in hormone-positive breast cancer patients treated with neoadjuvant FEC and triweekly docetaxel: a case series

We recently reported that neoadjuvant 5-FU, epirubicin, and cyclophosphamide (FEC) followed by weekly paclitaxel and/or trastuzumab induced a high pathological complete response (pCR) rate in hormone-negative patients. The present study examined the therapeutic efficacy of neoadjuvant FEC followed by triweekly docetaxel and/or trastuzumab in the treatment of hormone-positive patients. Between February 2012 and December 2013, 16 hormone-positive patients with local breast cancer (luminal A type: six patients; luminal B type: two patients; luminal HER2 type: eight patients) were included in the study. The histological type of the primary cancer was invasive ductal carcinoma in all patients. The cancer stages in the 16 women who received this regimen were stage I in five (31.3%), IIA in four (25.0%), IIB in five (31.3%), IIIB in one (6.3%), and IIIC in one (6.3%). Regarding clinical TNM classification, five patients were T1N0M0, one was T1N1M0, three were T2N0M0, five were T2N1M0, one was T3N2M0, and one was T4N0M0. The pCR was evaluated using resected tissue after neoadjuvant chemotherapy according to the evaluation criteria of the Japanese Breast Cancer Society. Patients were classified into pathologic responders (grade 2: 50.0% of all patients: 2/6 of luminal A type; 6/8 of Luminal HER2 type) and nonresponders (grades 0 and 1: 50.0% of all patients: 4/6 of luminal A type; 2/2 of luminal B type; 2/8 of luminal HER2 type) according to the grade of the tumor. The pCR rate was 0%. Hematologic and nonhematologic toxicity was reversible and manageable. This study demonstrated that neoadjuvant FEC followed by triweekly docetaxel and/or trastuzumab did induce a high pathologic response in luminal HER2 type, but not in luminal A and B types, and did not induce a high pCR rate in the hormone-positive patients.

Pertuzumab: a new targeted therapy for HER2-positive metastatic breast cancer

Trastuzumab, a humanized monoclonal antibody, has become an important targeted therapy for patients with all stages of human epidermal growth factor receptor-2 (HER2)-positive breast cancer. However, primary and acquired resistance to trastuzumab remains a significant problem. Pertuzumab, a humanized monoclonal antibody that binds to a domain of the HER2 receptor separate from trastuzumab, may have the potential to overcome trastuzumab resistance. Clinical trials have shown that pertuzumab can be effectively combined with other biologic therapy or chemotherapy in patients with metastatic HER2-positive breast cancer. Pertuzumab is relatively well tolerated with minimal increases in hematologic and cardiac toxicity observed when added to trastuzumab and/or docetaxel. In addition to becoming the standard of care in combination with docetaxel and trastuzumab in patients with newly diagnosed HER2-positive metastatic breast cancer, clinical trials continue to evaluate pertuzumab in combination with other targeted therapy, chemotherapy, and in patients with early stage breast cancer. These trials will help to further determine the role of pertuzumab in the treatment of HER2-positive breast cancer.

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

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

Pertuzumab, trastuzumab, and docetaxel for HER2-positive metastatic breast cancer (CLEOPATRA study): overall survival results from a randomised, double-blind, placebo-controlled, phase 3 study

BACKGROUND

CLEOPATRA is a phase 3 study to compare the efficacy and safety of pertuzumab, trastuzumab, and docetaxel with placebo, trastuzumab, and docetaxel in patients with HER2-positive first-line metastatic breast cancer. The results of the primary analysis showed significantly longer median progression-free survival in the pertuzumab group than in the placebo group. Interim analysis of overall survival favoured the pertuzumab group but was not significant. Here, we report results for overall survival after an additional year of follow-up.

METHODS

The study was a double-blind randomised trial undertaken at 204 centres in 25 countries. Patients with HER2-positive metastatic breast cancer who had not received previous chemotherapy or biological treatment for their metastatic disease were randomly assigned to receive either pertuzumab, trastuzumab, and docetaxel (n=402) or the same regimen with a matching placebo replacing pertuzumab (n=406). Randomisation was in a 1:1 ratio, stratified by geographical region and previous treatment status. The primary endpoint was progression-free survival (assessed independently), which has been reported previously; no follow-up data were gathered for the primary endpoint. Secondary endpoints included overall survival, progression-free survival (assessed by investigator), objective response rate, and safety. Median follow-up was 30 months in both groups. Efficacy endpoints were analysed in the intention-to-treat population and safety was analysed by treatment received. The study is completed but safety and survival data continue to be followed up. This trial is registered with ClinicalTrials.gov, number NCT00567190.

FINDINGS

In the intention-to-treat population, 267 patients died by data cutoff (May 14, 2012), 154 (38%) of 406 in the placebo group and 113 (28%) of 402 in the pertuzumab group. Median overall survival was 37.6 months (95% CI 34.3-NE [not estimable]) in the placebo group but had not been reached (95% CI 42.4-NE) in the pertuzumab group (hazard ratio 0.66, 95% CI 0.52-0.84; p=0.0008). Investigator-assessed median progression-free survival was 12.4 months (95% CI 10.4-13.5) in the placebo group and 18.7 months (16.6-21.6) in the pertuzumab group (hazard ratio 0.69, 95% CI 0.58-0.81). Serious adverse events were reported in 115 (29%) of 396 patients who received placebo, trastuzumab, and docetaxel and 148 (36%) of 408 who received pertuzumab, trastuzumab, and docetaxel, and included febrile neutropenia, neutropenia, diarrhoea, pneumonia, and cellulitis. Overall, adverse events were similar to those reported at the primary analysis with respect to frequency, severity, and specificity.

INTERPRETATION

Our analysis shows a significant improvement in overall survival with pertuzumab, trastuzumab, and docetaxel in patients with HER2-positive metastatic breast cancer, compared with placebo, trastuzumab, and docetaxel. Since this effect was not achieved at the expense of adverse events, this regimen represents a substantial improvement on the standard of care for this population of patients.

FUNDING

F Hoffmann-La Roche, Genentech.

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.

A phase II study of eribulin in Japanese patients with heavily pretreated metastatic breast cancer

BACKGROUND

Eribulin mesylate is a non-taxane microtubule dynamics inhibitor that recently gained Food and Drug Administration approval for late-line metastatic breast cancer (MBC).

PATIENTS AND METHODS

In this single-arm, multicentre open-label phase II trial Japanese patients pretreated with an anthracycline and a taxane received 1.4 mg/m(2) eribulin mesylate (2- to 5-min i.v. infusion on days 1 and 8 of a 21-day cycle). The primary efficacy end point was overall response rate (ORR) by independent review.

RESULTS

Patients (N = 80) had received a median of three prior chemotherapy regimens (range 1-5). ORR was 21.3% [95% confidence interval (CI) 12.9-31.8; all partial responses (PRs)], stable disease (SD) occurred in 30 patients (37.5%) and the clinical benefit rate (complete response + PR + SD ≥6 months) was 27.5% (95% CI 18.1-38.6). Median duration of response was 3.9 months (95% CI 2.8-4.9), progression-free survival was 3.7 months (95% CI 2.0-4.4) and overall survival was 11.1 months (95% CI 7.9-15.8). The most frequent treatment-related grade 3/4 adverse events were neutropenia (95.1%), leukopenia (74.1%) and febrile neutropenia (13.6%). Grade 3 peripheral neuropathy occurred in 3.7% of patients (no grade 4).

CONCLUSIONS

Eribulin exhibited efficacy and tolerability in Japanese patients with heavily pretreated MBC.

Surrogacy of tumor response and progression-free survival for overall survival in metastatic breast cancer resistant to both anthracyclines and taxanes

BACKGROUND

In breast cancer, the validity of surrogate endpoints for overall survival (OS) is a matter of controversy.

METHODS

In order to generate a hypothesis, we evaluated whether tumor response or progression-free survival (PFS) could be valid surrogates for OS in patients with metastatic breast cancer. Data from 30 patients were available from a phase II study of trastuzumab and capecitabine in human epidermal growth factor receptor 2-overexpressing metastatic breast cancer resistant to both anthracyclines and taxanes. The proportional hazards (PH) model was applied to evaluate the relationship between OS and tumor response or PFS. In addition, to explore prognostic factors influencing OS or post-progression survival, the PH model with a stepwise regression procedure was applied.

RESULTS

The relationship between tumor response and PFS was highly significant (P = 0.0036); however, there was no significant relationship between tumor response and OS or between PFS and OS. In the multivariate analysis, the sum of the longest diameter of target lesions (P = 0.0011), neutrophil count (P = 0.0033), and creatinine (P = 0.0085) were statistically significantly associated with OS.

CONCLUSION

We generated a hypothesis that neither PFS nor tumor response were valid as surrogate endpoints for OS, at least in the phase II trial for metastatic breast cancer resistant to both anthracyclines and taxanes. We also found that the sum of the longest diameter of target lesions, neutrophil count, and creatinine were prognostic factors for OS.

Promising molecular targeted therapies in breast cancer

In recent years, there has been a significant improvement in the understanding of molecular events and critical pathways involved in breast cancer. This has led to the identification of novel targets and development of anticancer therapies referred to as targeted therapy. Targeted therapy has high specificity for the molecules involved in key molecular events that are responsible for cancer phenotype such as cell growth, survival, migration, invasion, metastasis, apoptosis, cell-cycle progression, and angiogenesis. Targeted agents that have been approved for breast cancer include trastuzumab and lapatinib, directed against human epidermal growth factor receptor 2 (HER2) and bevacizumab, directed against vascular endothelial growth factor (VEGF). Several other targeted agents currently under evaluation in preclinical and clinical trials include inhibitors of epidermal growth factor receptor (EGFR), dual EGFR and HER2 inhibitors, VEGF/VEGFR inhibitors, and agents that interfere with crucial signaling pathways such as PI3K/AKT/mTOR and RAS/MEK/ERK; agents against other tyrosine kinases such as Src, insulin-like growth factor (IGF)/IGF-receptor (IGFR); agents that promote apoptosis such as Poly ADP ribose polymerase inhibitors; agents that target invasion and metastasis such as matrix metalloproteinases inhibitors and others. In this review, we highlight the most promising targeted agents and their combination with mainstream chemotherapeutic drugs in clinical trials.

[Treatment possibilities in breast cancer progressing after anthracyclines and/or taxanes]

The treatment of recurrent, progressing, metastatic breast cancer, which has previously been exposed to anthracyclines and/or taxanes is not only a major clinical challenge, but has a significant social impact too. In the absence of formal guidelines, this review has aimed to summarize the published evidence that is needed to guide clinical decision-making. Four new agents are approved for use in this setting: capecitabine, gemcitabine, ixabepilone, and nanoparticle albumin-bound paclitaxel. Nevertheless this review summarizes the results of studies with other active agents, as liposomal doxorubicin, rotation of taxanes, larotaxel, vinorelbine, and other biological agents.

Capecitabine monotherapy is efficient and safe in all line settings in patients with metastatic and advanced breast cancer

OBJECTIVE

Capecitabine is effective and well tolerated in patients with anthracycline- and/or taxane-pre-treated metastatic breast cancer. We compared the efficacy and safety of capecitabine monotherapy between 1st, 2nd, 3rd and > or =4th line settings for advanced and metastatic breast cancer pre-treated with/without anthracycline and taxanes.

METHODS

Subjects comprised 84 patients with histologically confirmed advanced or metastatic breast cancer and at least one measurable metastatic lesion. We evaluated time to disease progression (TTP), response rate (RR) and clinical benefit rate (CBR) for 1st (n = 17), 2nd (n = 28), 3rd (n = 23) and > or =4th (n = 16) line setting treatments of capecitabine monotherapy.

RESULTS

Median number of cycles of capecitabine monotherapy was 12 cycles in 1st line, 11 cycles in 2nd line, 9 cycles in 3rd line and 11 cycles in > or =4th line. RR and CBR were 23.5% and 58.8% in 1st line, 21.4% and 53.6% in 2nd line, 21.7% and 52.2% in 3rd line, and 18.8% and 50.0% in > or =4th line, respectively. No significant differences in TTP were seen between each line setting (P = 0.843).

CONCLUSIONS

Capecitabine monotherapy is effective and well tolerated in all line settings of chemotherapy in patients with metastatic or advanced breast cancer, and is suitable for outpatient therapy.

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.