Ixabepilone plus capecitabine in metastatic breast cancer patients with reduced performance status previously treated with anthracyclines and taxanes: a pooled analysis by performance status of efficacy and safety data from 2 phase III studies

Ixabepilone: Overview of Effectiveness, Safety, and Tolerability in Metastatic Breast Cancer

Treatment algorithms for metastatic breast cancer describe sequential treatment with chemotherapy and, if appropriate, targeted therapy for as long as the patient receives benefit. The epothilone ixabepilone is a microtubule stabilizer approved as a monotherapy and in combination with capecitabine for the treatment of metastatic breast cancer in patients with demonstrated resistance to anthracyclines and taxanes. While chemotherapy and endocrine therapy form the backbone of treatment for metastatic breast cancer, the epothilone drug class has distinguished itself for efficacy and safety among patients with disease progression during treatment with chemotherapy. In phase III trials, ixabepilone has extended progression-free survival and increased overall response rates, with a manageable toxicity profile. Recent analyses of subpopulations within large pooled datasets have characterized the clinical benefit for progression-free survival and overall survival for ixabepilone in special populations, such as patients with triple-negative breast cancer or those who relapsed within 12 months of prior treatment. Additional investigation settings for ixabepilone therapy discussed here include adjuvant therapy, weekly dosing schedules, and ixabepilone in new combinations of treatment. As with other microtubule stabilizers, ixabepilone treatment can lead to peripheral neuropathy, but evidence-based management strategies may reverse these symptoms. Dose reductions did not appear to have an impact on the efficacy of ixabepilone plus capecitabine. Incorporation of ixabepilone into individualized treatment plans can extend progression-free survival in a patient population that continues to represent an unmet need.

Efficacy and Safety of Capecitabine Alone or in Combination in Advanced Metastatic Breast Cancer Patients Previously Treated with Anthracycline and Taxane: A Systematic Review and Meta-Analysis

BACKGROUND

Capecitabine is frequently used alone or combined with other chemotherapy agents for the treatment of metastatic breast cancer in relapsed patients.

OBJECTIVE

The objective of this meta-analysis is to evaluate the effectiveness and safety of capecitabine monotherapy versus combination in the treatment of metastatic breast cancer patients pretreated with anthracycline and taxane.

METHODS

Eligible randomized controlled trials examining the efficacy and safety of capecitabine alone compared to capecitabine combination were systematically searched. Progression-free survival (PFS), overall survival (OS), overall response rate (ORR), and grades 3-4 drug-related adverse events were the outcomes assessed.

RESULTS

A total of 6,714 patients of 9 trials were involved in the pooled analysis. Our findings demonstrated that capecitabine combination is significantly superior to capecitabine monotherapy in improving PFS (hazard ratio [HR] 1.32, 95% CI 1.13-1.54, p < 0.0001) and ORR (risk ratio [RR] 0.67, 95% CI 0.54-0.83, p < 0.001), but it was insignificant in OS (HR 1.09, 95% CI 0.98-1.22, p = 0.12). On the other hand, the incidence of non-hematological adverse events such as hand-foot syndrome and diarrhea was lower in capecitabine combination compared to capecitabine monotherapy.

CONCLUSION

Capecitabine-based combination chemotherapy showed superiority over capecitabine monotherapy in terms of PFS and ORR, with no significant difference in OS. Non-hematological adverse effects such as hand-foot syndrome were fewer with a combination regimen. However, hematological adverse events were fewer with capecitabine monotherapy regimen.

UCBG 2-08: 5-year efficacy results from the UNICANCER-PACS08 randomised phase III trial of adjuvant treatment with FEC100 and then either docetaxel or ixabepilone in patients with early-stage, poor prognosis breast cancer

PURPOSE

UNICANCER-PACS08 compared adjuvant FEC (5-FU; epirubicin; cyclophosphamide) then docetaxel to FEC then ixabepilone in poor prognosis early breast cancer (BC). We evaluated whether replacing docetaxel with ixabepilone would increase 5-year disease-free survival (DFS).

PATIENTS AND METHODS

Triple-negative breast cancer (TNBC) or oestrogen receptor (ER)+/progesterone receptor (PR)-/HER2- BC patients were randomised to receive standard FEC (3 cycles) followed by 3 cycles of either docetaxel (100 mg/m²) or ixabepilone (40 mg/m²). Radiotherapy was mandatory after conservative surgery; ER+ patients received endocrine therapy.

RESULTS

Seven hundred sixty-two patients were enrolled between October 2007 and September 2010. Baseline characteristics were balanced between arms. Median follow-up was 66.7 months. Median DFS was not reached; 5-year DFS rate was 76% with docetaxel and 79% with ixabepilone (hazard ratio [HR] = 0.80; 95% confidence interval [CI] = 0.58-1.10; p = 0.175). Median overall survival (OS) was not reached; 5-year OS rate was 86% versus 84% (HR = 0.97; 95% CI = 0.66-1.42; p = 0.897). TNBC patients treated with ixabepilone had a 23% lower risk of relapse compared to docetaxel (HR for DFS = 0.77; 95% CI = 0.53-1.11; p = 0.168). DFS was longer with ixabepilone than docetaxel in patients with grade II-III lymphocytic infiltration (HR = 0.55; 95% CI = 0.29-1.05; p = 0.063). All patients experienced ≥1 adverse events (AEs): 75% reported grade III-IV AEs and two (<1%) had grade V AEs (both with neutropenia and infection receiving ixabepilone).

CONCLUSION

After adjuvant FEC, ixabepilone was comparable to docetaxel for treating poor prognosis early BC patients. The benefit of ixabepilone in subgroups (patients with TNBC and grade II-III lymphocytic infiltration) requires further evaluation.

A meta-analysis of combination therapy versus single-agent therapy in anthracycline- and taxane-pretreated metastatic breast cancer: results from nine randomized Phase III trials

Nowadays, the philosophy of treating metastatic breast cancer (MBC) is slowly evolving. Especially for the anthracycline- and taxane-pretreated MBC patients, no standard therapy exists in this setting. Whether to choose doublet agents or single agent as salvage treatment remains fiercely debated. Thus, we conducted a meta-analysis to resolve this problem. Databases including PubMed, EMBASE, and Cochrane library were searched for Phase III randomized clinical trials (published before August 2015) comparing the efficacy and adverse effects between the combination therapy and single-agent therapy in anthracycline- and taxane-pretreated MBC patients. The primary end point was the overall survival (OS), and the secondary end points were the progression-free survival (PFS), overall response rate (ORR), and grade 3 or 4 toxicities. The pooled hazard ratio (HR) and pooled risk ratio (RR) were used to evaluate the efficacy. Analyses were also performed to estimate the side effects and safety of both groups. In all, nine eligible randomized clinical trials were included in this meta-analysis. Improvements were proven in the doublet agents group on OS (HR 0.90, 95% confidence interval [CI] 0.84–0.96, P=0.002), PFS (HR 0.81, 95% CI 0.76–0.88, P<0.001), and ORR (RR 1.72, 95% CI 1.34–2.21, P<0.001). Notably, subgroup analysis failed to favor the targeted agent-based combination in terms of OS (HR 1.08, 95% CI 0.89–1.31, P=0.365), PFS (HR 1.09, 95% CI 0.88–1.35, P=0.433), and ORR (RR 1.60, 95% CI 0.69–3.71, P=0.278) compared with single agent. In addition, although more hematological and gastrointestinal toxicities were observed in the doublet agents group, they were acceptable and manageable. Taken together, when compared with single-agent therapy, doublet agents should be considered a treatment option because of the superior efficacy and the manageable safety profile for the prior anthracycline- and taxane-treated MBC patients.

CCR 20th anniversary commentary: BMS-247550—microtubule stabilization as successful targeted therapy

In a landmark article published in the May 1, 2001, issue of Clinical Cancer Research, Lee and colleagues reported the original preclinical studies demonstrating anticancer activity of BMS-247550 (ixabepilone) against taxane-sensitive and taxane-resistant cancers. Subsequent clinical trials established the clinical efficacy of ixabepilone, leading to its regulatory approval for the treatment of drug-resistant metastatic or locally advanced breast cancers.

Correlation between rest-activity rhythm and survival in cancer patients experiencing pain

The purpose of this study was to investigate the influence of rest-activity rhythm on the survival of cancer patients. This study collected data related to cancer patients experiencing pain who had been hospitalized for treatment between August 2006 and October 2007. Data included the Karnofsky Performance Status Index as a representation of functional condition as well as the Brief Pain Inventory and the Pittsburgh Sleep Quality Index. Actigraphic methods were used to record the dichotomy index (I < O) of patients' rest-activity rhythms over periods of three consecutive days. Patients were closely followed until 31 July 2013. Results were analyzed using Kaplan-Meier survival analysis, log-rank testing and Cox proportional hazards regression analysis to evaluate whether alterations in the rest-activity rhythm affected the survival rate of the patients. Of the 68 hospitalized cancer patients experiencing pain at the time of admission, 51 subsequently died within the study period. A significant difference was observed in the survival curves between the regular I < O group and the disrupted I < O group (log rank = 7.942, p = 0.005). A multivariable proportional hazard model was used for analysis of overall survival, revealing that the risk of death within the study period among patients with disrupted I < O was 4.59 times higher than that of patients with regular I < O (95% CI: 1.92-10.96, p = 0.001). Among patients with poor performance status, the risk of death among patients with disrupted I < O was 8.68 times higher than that of patients with regular I < O (95% CI: 2.50-30.09, p = 0.001). Disruptions in rest-activity rhythm were negatively correlated with the survival of hospitalized cancer patients experiencing pain. Effects were particularly pronounced in cancer patients with poor performance status.

5-FU and ixabepilone modify the microRNA expression profiles in MDA-MB-453 triple-negative breast cancer cells

This study aimed to discover new potential mechanisms of chemotherapy with drugs used in the treatment of luminal androgen receptor (LAR)-type triple-negative breast cancer (TNBC). We examined the microRNA (miRNA) expression profiles of LAR-type TNBC in vitro, and explored the variation in miRNA expression profiles in cells when treated with the chemotherapy drugs capecitabine and ixabepilone. The present study revealed that the expression levels of the three antitumor miRNAs, miR-122a, miR-145 and miR-205, were significantly elevated in MDA-MB-453 LAR-type TNBC tumor cells treated with 5-fluorouracil together with ixabepilone. By contrast, carcinogenic miR-296 miRNA expression significantly declined, and levels of several other miRNAs such as miR-221, miR-210, miR-21 and miR-10b were also altered. The drugs may exert their effects through the regulation of miRNA expression levels, thereby providing a theoretical basis for clinical implementation of miRNA expression profiles as a diagnostic method for the early diagnosis, classification and prognosis of breast cancer.

Antimitotic agents for the treatment of patients with metastatic castrate-resistant prostate cancer

INTRODUCTION

Metastatic castrate-resistant prostate cancer (mCRPC) is the second deadliest cancer in men. The group of taxanes, which target microtubules of mitotic cells, is currently the only chemotherapy which has proven to increase overall survival in mCRPC patients. Other mitotic inhibitors are being explored for their clinical potential in mCRPC treatment.

AREAS COVERED

In this review, we summarize recent developments in the application of mitotic inhibitors for mCRPC from a clinical perspective. The four main groups of mitotic inhibitors currently being tested in clinical trials are microtubule-inhibitors, polo-like kinase 1 inhibitors, aurora kinase inhibitors and kinesin-spindle protein inhibitors. Compounds of these groups of inhibitors that are in clinical development for mCRPC are discussed. For this extensive overview, relevant literature was searched in PubMed and retrieved from clinicaltrials.gov and presentations at ASCO/AACR meetings.

EXPERT OPINION

In general, mitotic inhibitors are clinically well tolerated but exert limited antitumor activity compared to preclinical study results. However, efficacy of mitotic inhibitors is improving, either by personalizing treatment, by introducing more active compounds, by decreasing resistance of cancer cells against mitotic inhibitors or by using mitotic inhibitors in combination therapies.

Chemotherapy in Patients with Anthracycline- and Taxane-Pretreated Metastatic Breast Cancer: An Overview

Anthracyclines and taxanes are cytotoxic agents that are commonly used for the treatment of breast cancer, including in the adjuvant, neoadjuvant, and metastatic setting. Each drug class of is associated with cumulative and potentially irreversible toxicity, including cardiomyopathy (anthracyclines) and neuropathy (taxanes). This may either limit the duration of therapy for advanced disease, or prevent retreatment for recurrence if previously used as component of adjuvant or neoadjuvant therapy. Several classes of cytotoxic agents have been evaluated in patients with anthracycline and taxane-pretreated metastatic breast cancer (MBC), including other antitubulins (vinorelbine, ixabepilone, eribulin), antimetabolites (capecitabine, gemcitabine), topoisomerase I inhibitors (irinotecan), platinum analogues (cisplatin, carboplatin), and liposomal doxorubicin preparations. No trials have shown an overall survival advantage for combination chemotherapy in this setting, indicating that single cytotoxic agents should usually be used, expect perhaps in patients with rapidly progressive disease and/or high tumor burden.

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.

Beyond taxanes: the next generation of microtubule-targeting agents

Taxanes are a standard first-line option for metastatic breast cancer (MBC), but their utility may be limited by primary or acquired resistance. New microtubule-targeting agents have been developed to overcome taxane resistance and provide additional options for improving patient outcomes. This article reviews these alternative microtubule-targeting agents and their potential clinical benefits for MBC patients. Relevant clinical data were compiled through searches within PubMed and congress abstract databases. Ixabepilone, a novel microtubule-stabilizing drug approved by the US Food and Drug Administration (FDA), has proven efficacy across multiple lines of therapy, including patients with taxane-resistant/refractory disease. In phase III trials, ixabepilone plus capecitabine significantly improved progression-free survival compared with capecitabine alone in anthracycline/taxane-pretreated patients. Eribulin has recently been approved by the FDA and by the European Medicines Agency for the treatment of patients with MBC who have received at least two prior chemotherapy regimens for late-stage disease. In a phase III trial, eribulin extended overall survival compared with the physician’s treatment choice in heavily pretreated MBC patients. In addition, several investigational microtubule-targeting agents may have therapeutic potential in MBC. The development of new microtubule-targeting agents helps to address the need for additional effective regimens for patients progressing after standard treatment with anthracycline- and taxane-containing regimens.

Triple-negative and basal-like breast cancer: implications for oncologists

Since the start of the 1990s, molecular pathology has been playing an increasingly important role in cancer diagnosis and treatment.[...]

Overall survival as the outcome for randomized clinical trials with effective subsequent therapies

We review how overall survival (OS) comparisons should be interpreted with increasing availability of effective therapies that can be given subsequently to the treatment assigned in a randomized clinical trial (RCT). We examine in detail how effective subsequent therapies influence OS comparisons under varying conditions in RCTs. A subsequent therapy given after tumor progression (or relapse) in an RCT that works better in the standard arm than the experimental arm will lead to a smaller OS difference (possibly no difference) than one would see if the subsequent therapy was not available. Subsequent treatments that are equally effective in the treatment arms would not be expected to affect the absolute OS benefit of the experimental treatment but will make the relative improvement in OS smaller. In trials in which control arm patients cross over to the experimental treatment after their condition worsens, a smaller OS difference could be observed than one would see without cross-overs. In particular, use of cross-over designs in the first definitive evaluation of a new agent in a given disease compromises the ability to assess clinical benefit. In disease settings in which there is not an intermediate end point that directly measures clinical benefit, OS should be the primary end point of an RCT. The observed difference in OS should be considered the measure of clinical benefit to the patients, regardless of subsequent therapies, provided that the subsequent therapies used in both treatment arms follow the current standard of care.

Ixabepilone for the treatment of breast cancer

Patients with breast cancer that becomes resistant to taxanes and anthracyclines experience considerable morbidity and mortality. The Food and Drug Administration has approved the use of ixabepilone for the treatment of patients with locally advanced or metastatic breast cancer that is refractory or resistant to taxanes and anthracyclines. The purpose of this review is to summarize the evidence from published studies on the pharmacological data and clinical activity of ixabepilone in patients with breast cancer. The conclusion of this review is that ixabepilone demonstrated a high efficacy in combination with capecitabine and as a single agent in breast cancer refractory to taxanes and anthracyclines. The clinical activity of ixabepilone combined with bevacizumab for advanced breast cancer was very promising.