Erica L. Mayer

Adherence to Initial Adjuvant Anastrozole Therapy Among Women With Early-Stage Breast Cancer

PURPOSE Previous research evaluating adherence to tamoxifen therapy among women with early-stage breast cancer has revealed adherence estimates ranging from 25% to 96%. No previous studies have focused on adherence to adjuvant aromatase inhibitors. METHODS We used longitudinal claims data from three large commercial health programs to estimate adherence with anastrozole therapy among women with early-stage breast cancer. Adherence was defined as the proportion of days that patients had medication available over the observation period (ie, days covered); women with fewer than 80% of days covered were defined as nonadherent. RESULTS More than 12,000 women in the databases were found to have new anastrozole prescription claims during the period of study: 1,498 women were classified as having early-stage disease in one commercial health program (Plan A) data set, 1,899 women in another program (Plan B) data set, and 8,994 women in MarketScan, a commercial data set made up of several health programs. Mean adherence over the first 12 months of therapy ranged from 82% to 88% in the three data sets. Between 19% and 28% of women had fewer than 80% of days covered. For women with 36 months of continuous eligibility, the mean adherence decreased each year, ranging from 78% to 86% in year 1 to 62% to 79% in year 3 within the three data sets. CONCLUSION A substantial proportion of women with early-stage breast cancer may be suboptimally adherent to adjuvant anastrozole therapy. Future research should focus on the identification of patients at risk for nonadherence with oral hormonal therapy for breast cancer and the development of interventions to improve adherence.

TBCRC 001: Randomized Phase II Study of Cetuximab in Combination With Carboplatin in Stage IV Triple-Negative Breast Cancer

PURPOSE Epidermal growth factor receptor (EGFR) is a targetable receptor frequently overexpressed in basal-like breast cancer, which comprises most triple-negative breast cancers (TNBCs), the only subtype without established targeted therapy. PATIENTS AND METHODS In this randomized phase II trial, patients with metastatic TNBC received anti-EGFR antibody cetuximab (400 mg/m(2) load then 250 mg/m(2) per week intravenously [IV]) alone, with carboplatin (area under the curve of 2, once per week IV) added after progression or as concomitant therapy from the beginning. Response rate (RR) was the primary end point; others included time to progression (TTP), overall survival (OS), and toxicity. Embedded correlative studies included molecular subtyping on archival tissue. Fresh tumor tissue before and after 7 to 14 days of therapy was used for microarray analyses exploring EGFR pathway activity and inhibition. RESULTS In 102 patients with TNBC, RRs were 6% (two of 31) to cetuximab and 16% (four of 25) to cetuximab plus carboplatin after progression. RR to those treated from the beginning with cetuximab plus carboplatin was 17% (12 of 71); 31% of patients responded or had prolonged disease stabilization. The cetuximab plus carboplatin regimen was well tolerated, but both TTP and OS were short at 2.1 months (95% CI, 1.8 to 5.5 months) and 10.4 months (95% CI, 7.7 to 13.1 months), respectively. Of 73 patients with archival tissue for analysis, 74% had basal-like molecular subtype. Sixteen patients had tumor biopsies before and 1 week after therapy; genomic patterns of the EGFR pathway showed activation in 13 and inhibition by therapy in five. CONCLUSION Despite strong preclinical data, combination cetuximab plus carboplatin in metastatic TNBC produced responses in fewer than 20% of patients. EGFR pathway analysis showed that most TNBCs involved activation. However, cetuximab blocked expression of the EGFR pathway in only a minority, suggesting that most had alternate mechanisms for pathway activation.

Congestive Heart Failure Risk in Patients With Breast Cancer Treated With Bevacizumab

PURPOSE Bevacizumab is a treatment option in patients with metastatic breast cancer. Congestive heart failure (CHF) has been reported, although the overall incidence and relative risk (RR) of this complication remains unclear. We performed an up-to-date, comprehensive meta-analysis to determine the risk of serious CHF in patients with breast cancer receiving bevacizumab. METHODS The databases of Medline were searched for articles from 1966 to March 2010. Abstracts presented at the American Society of Clinical Oncology and the San Antonio Breast Cancer Symposium meetings were also searched for relevant clinical trials. Eligible studies include randomized trials with bevacizumab in patients with breast cancer. Adequate reporting of safety profile data was required for inclusion. Statistical analyses were conducted to calculate the summary incidence, RR, and 95% CIs by using random-effects models. RESULTS A total of 3,784 patients were included. Overall incidence results for high-grade CHF in bevacizumab- and placebo-treated patients were 1.6% (95% CI, 1.0% to 2.6%) and 0.4% (95% CI, 0.2% to 1.0%), respectively. The RR of CHF in bevacizumab-treated patients was 4.74 (95% CI, 1.66 to 11.18; P = .001) compared with placebo-treated ones. In subgroup analyses, there were no significant differences in CHF incidence or risk between patients treated with low-dose (2.5 mg/kg) versus high-dose (5 mg/kg) bevacizumab or among patients treated with different chemotherapy regimens. No evidence of publication bias was observed. CONCLUSION This is the first comprehensive report to show that bevacizumab is associated with an increased risk of significant heart failure in patients with breast cancer.

TBCRC009: A Multicenter Phase II Clinical Trial of Platinum Monotherapy With Biomarker Assessment in Metastatic Triple-Negative Breast Cancer

PURPOSE The identification of patients with metastatic triple-negative breast cancer (mTNBC) who are expected to benefit from platinum-based chemotherapy is of interest. We conducted a single-arm phase II clinical trial of single-agent platinum for mTNBC with biomarker correlates. PATIENTS AND METHODS Patients with mTNBC received first- or second-line cisplatin (75 mg/m(2)) or carboplatin (area under the concentration-time curve 6) by physicians choice once every 3 weeks. Coprimary end points were objective response rate (RR) and response prediction by p63/p73 gene expression. Secondary and exploratory end points included toxicity assessment, RR in cisplatin versus carboplatin, and RR in molecularly defined subgroups, including BRCA1/2 mutation carriers. RESULTS Patients (N = 86; 69 as first-line therapy) received cisplatin (n = 43) or carboplatin (n = 43). RR was 25.6% (95% CI, 16.8% to 36%) and was numerically higher with cisplatin (32.6%) than with carboplatin (18.7%). RR was 54.5% in patients with germline BRCA1/2 mutations (n = 11). In patients without BRCA1/2 mutations (n = 66), exploratory analyses showed that a BRCA-like genomic instability signature (n = 32) discriminated responding and nonresponding tumors (mean homologous recombination deficiency-loss of heterozygosity/homologous recombination deficiency-large-scale state transitions [HRD-LOH/HRD-LST] scores were 12.68 and 5.11, respectively), whereas predefined analysis by p63/p73 expression status (n = 61), p53 and PIK3CA mutation status (n = 53), or PAM50 gene expression subtype (n = 55) did not. Five of the six long-term responders alive at a median of 4.5 years lacked germline BRCA1/2 mutations, and two of them had increased tumor HRD-LOH/HRD-LST scores. CONCLUSION Platinum agents are active in mTNBC, especially in patients with germline BRCA1/2 mutations. A measure of tumor DNA repair function may identify patients without mutations who could benefit from platinum therapy agents. Prospective controlled confirmatory trials are warranted.

Advances in Targeting Src in the Treatment of Breast Cancer and Other Solid Malignancies

Src, a membrane-associated nonreceptor tyrosine kinase, plays a crucial role in the coordination and facilitation of cell-signaling pathways controlling a wide range of cellular functions, including growth, survival, invasion, adhesion, and migration. Deregulation and increased activity of Src has been observed in multiple human malignancies, prompting the development of specific inhibitors of Src. In preclinical studies, Src inhibitors show antitumor effects in multiple solid tumor types. Recently completed early-phase trials using the inhibitors dasatinib and bosutinib have suggested modest activity as monotherapy in breast and prostate cancer, with potentially greater activity in combination regimens. Given the interaction between Src and the estrogen receptor, ongoing trials are exploring combinations with endocrine therapy. The relationship between Src and the vascular endothelial growth factor receptor also justifies investigation of combinations with angiogenesis inhibitors. Future trials will continue to explore the contribution of Src inhibition with both chemotherapy and targeted agents. Clin Cancer Res; 16(14); 3526–32. ©2010 AACR.

Cardiac Toxicity From Systemic Cancer Therapy: A Comprehensive Review

Cardiovascular toxicity is a potential short- or long-term complication of anticancer therapy. Exposure to chemotherapy medications, primarily the anthracycline class, can lead to potentially irreversible clinically significant cardiac dysfunction. The advent of novel biologic agents, including monoclonal antibodies and tyrosine kinase inhibitors, has revolutionized the treatment of several types of malignancies. Although targeted therapies are considered less toxic and better tolerated by patients compared with classic chemotherapy agents, rare serious complications have been observed; and longer-term follow-up is needed to determine the exact profile of related cardiac adverse effects. Cardiac toxicity associated with cancer therapies can range from asymptomatic subclinical abnormalities, including electrocardiographic changes and temporary left ventricular ejection fraction decline, to life-threatening events such as congestive heart failure or acute coronary syndromes. Assessment of the prevalence, type, and severity of cardiac toxicity caused by various cancer treatments is a critical topic for patient management and specifically for new drug development. Guidelines for monitoring cardiac adverse effects have been formulated; however, appropriate supportive evidence remains limited. Given the rate of new drug development designed to fulfill unmet oncologic needs, efforts are needed to promote strategies for cardiac risk detection and management and to avoid unintended consequences potentially impeding development of, regulatory approval for, and patient access to novel therapies. These advances require ongoing research to assess and manage the cardiovascular safety of patients treated with anticancer agents, as well as a well-organized collaboration between oncologists and cardiologists. The aim of this review is to summarize potential cardiovascular toxicities for a range of cancer chemotherapeutics and to review general mechanisms of cardiovascular toxicity for each agent.

Prevention and Monitoring of Cardiac Dysfunction in Survivors of Adult Cancers: American Society of Clinical Oncology Clinical Practice Guideline

Purpose Cardiac dysfunction is a serious adverse effect of certain cancer-directed therapies that can interfere with the efficacy of treatment, decrease quality of life, or impact the actual survival of the patient with cancer. The purpose of this effort was to develop recommendations for prevention and monitoring of cardiac dysfunction in survivors of adult-onset cancers. Methods Recommendations were developed by an expert panel with multidisciplinary representation using a systematic review (1996 to 2016) of meta-analyses, randomized clinical trials, observational studies, and clinical experience. Study quality was assessed using established methods, per study design. The guideline recommendations were crafted in part using the Guidelines Into Decision Support methodology. Results A total of 104 studies met eligibility criteria and compose the evidentiary basis for the recommendations. The strength of the recommendations in these guidelines is based on the quality, amount, and consistency of the evidence and the balance between benefits and harms. Recommendations It is important for health care providers to initiate the discussion regarding the potential for cardiac dysfunction in individuals in whom the risk is sufficiently high before beginning therapy. Certain higher risk populations of survivors of cancer may benefit from prevention and screening strategies implemented during cancer-directed therapies. Clinical suspicion for cardiac disease should be high and threshold for cardiac evaluation should be low in any survivor who has received potentially cardiotoxic therapy. For certain higher risk survivors of cancer, routine surveillance with cardiac imaging may be warranted after completion of cancer-directed therapy, so that appropriate interventions can be initiated to halt or even reverse the progression of cardiac dysfunction.

Randomized Phase III Trial of Paclitaxel Once Per Week Compared With Nanoparticle Albumin-Bound Nab-Paclitaxel Once Per Week or Ixabepilone With Bevacizumab As First-Line Chemotherapy for Locally Recurrent or Metastatic Breast Cancer: CALGB 40502/NCCTG N063H (Alliance)

PURPOSE We compared nab-paclitaxel or ixabepilone once per week to paclitaxel with bevacizumab as first-line therapy for patients with advanced breast cancer (BC) to evaluate progression-free survival (PFS) for nab-paclitaxel or ixabepilone versus paclitaxel. PATIENTS AND METHODS Eligible patients were age ≥ 18 years with chemotherapy-naive advanced BC. Patients were randomly assigned to bevacizumab with paclitaxel 90 mg/m(2) (arm A), nab-paclitaxel 150 mg/m(2) (arm B), or ixabepilone 16 mg/m(2) (arm C), once per week for 3 of 4 weeks. Planned enrollment was 900 patients, which would give 88% power to detect a hazard ratio of 0.73. RESULTS In all, 799 patients were enrolled, and 783 received treatment (97% received bevacizumab). Arm C was closed for futility at the first interim analysis (n = 241), and arm A (n = 267) and arm B (n = 275) were closed for futility at the second interim analysis. Median PFS for paclitaxel was 11 months, ixabepilone was inferior to paclitaxel (PFS, 7.4 months; hazard ratio, 1.59; 95% CI, 1.31 to 1.93; P < .001), and nab-paclitaxel was not superior to paclitaxel (PFS, 9.3 months; hazard ratio, 1.20; 95% CI, 1.00 to 1.45; P = .054). Results were concordant with overall survival; time to treatment failure was significantly shorter in both experimental arms v paclitaxel. Hematologic and nonhematologic toxicity, including peripheral neuropathy, was increased with nab-paclitaxel, with more frequent and earlier dose reductions. CONCLUSION In patients with chemotherapy-naive advanced BC, ixabepilone once per week was inferior to paclitaxel, and nab-paclitaxel was not superior with a trend toward inferiority. Toxicity was increased in the experimental arms, particularly for nab-paclitaxel. Paclitaxel once per week remains the preferred palliative chemotherapy in this setting.

Cardiovascular Health of Patients With Cancer and Cancer Survivors : A Roadmap to the Next Level

Many existing and emerging cancer therapies have a significant effect on the cardiovascular health of patients with cancer and cancer survivors. This paper examines current aspects of interdisciplinary cardio-oncology clinical care delivery and education in the United States and outlines how these data provide a platform for future development of the field. We present the results of the nationwide survey on cardio-oncology services, practices, and opinions, conducted among chiefs of cardiology and program directors, which demonstrate ranges of clinical activities and identify significant interest for increased educational opportunities and expert training of cardiovascular physicians in this field. The survey respondents recognized clinical relevance but emphasized lack of national guidelines, lack of funds, and limited awareness and infrastructure as the main challenges for development and growth of cardio-oncology. We discuss potential solutions to unmet needs through interdisciplinary collaboration and the active roles of professional societies and other stakeholders.

A Phase 2 Trial of Dasatinib in Patients with Advanced HER2-Positive and/or Hormone Receptor–Positive Breast Cancer

Purpose: SRC-family kinases (SFK) are involved in numerous oncogenic signaling pathways. A phase 2 trial of dasatinib, a potent oral tyrosine kinase inhibitor of SFKs, was carried out in patients with human epidermal growth factor receptor 2–positive (HER2+) and/or hormone receptor–positive (HR+) advanced breast cancer. Experimental Design: Patients with measurable tumors and progression after chemotherapy and HER2 and/or HR-targeted agents in adjuvant or metastatic settings (maximum of two prior metastatic setting regimens) received twice daily dasatinib. Primary endpoint was Response Evaluation Criteria in Solid Tumors–defined response rate. Secondary endpoints included toxicity and limited pharmacokinetics. Results: Seventy patients (55 years median age) were treated, 83% of HER2+ patients had received prior HER2-directed therapy, and 61% of HR+ patients had received prior endocrine therapy in the advanced setting. Dasatinib starting dose was reduced from 100 to 70 mg twice daily to limit toxicity. Median therapy duration was 1.8 months in both dose groups and most discontinuations were due to progression. Of 69 evaluable patients, three had confirmed partial responses and six had stable disease for 16 weeks or more (disease control rate = 13.0%); all nine of these tumors were HR+ (two were also HER2+). The most common drug-related toxicities were gastrointestinal complaints, headache, asthenia, and pleural effusion. Grade 3–4 toxicity occurred in 37% of patients and was comparable between doses; drug-related serious adverse events were less frequent with 70 mg twice daily than 100 mg twice daily. Conclusion: Limited single-agent activity was observed with dasatinib in patients with advanced HR+ breast cancer. Clin Cancer Res; 17(21); 6897–904. ©2011 AACR.