Pharmacokinetics of Selected Anticancer Drugs in Elderly Cancer Patients: Focus on Breast Cancer

Chemotherapy Primary Dose Reduction in Older Cancer Patients: A Retrospective Cohort

Primary dose reduction (PDR) in the first course of chemotherapy is an empirical practice, commonly used in older population. Patients over 70 years old receiving a first course of chemotherapy for a solid tumor were enrolled. A total of 179 patients were included. Standard dose was used in 69.8% of patients, while 30.2% received PDR of chemotherapy. Only 29.6% received a standardized geriatric assessment. Patients receiving standard doses presented 83.2% of toxicities, while 68% of toxicities were reported in patients receiving PDR. The toxicity rate was significantly decreased in patients treated with reduced first-cycle dose of chemotherapy.

Predictive, preventive, and personalized medicine in breast cancer: targeting the PI3K pathway

Breast cancer (BC) is a multifaceted disease characterized by distinct molecular subtypes and varying responses to treatment. In BC, the phosphatidylinositol 3-kinase (PI3K) pathway has emerged as a crucial contributor to the development, advancement, and resistance to treatment. This review article explores the implications of the PI3K pathway in predictive, preventive, and personalized medicine for BC. It emphasizes the identification of predictive biomarkers, such as PIK3CA mutations, and the utility of molecular profiling in guiding treatment decisions. The review also discusses the potential of targeting the PI3K pathway for preventive strategies and the customization of therapy based on tumor stage, molecular subtypes, and genetic alterations. Overcoming resistance to PI3K inhibitors and exploring combination therapies are addressed as important considerations. While this field holds promise in improving patient outcomes, further research and clinical trials are needed to validate these approaches and translate them into clinical practice.

Key Considerations for the Treatment of Advanced Breast Cancer in Older Adults: An Expert Consensus of the Canadian Treatment Landscape

The prevalence of breast cancer amongst older adults in Canada is increasing. This patient population faces unique challenges in the management of breast cancer, as older adults often have distinct biological, psychosocial, and treatment-related considerations. This paper presents an expert consensus of the Canadian treatment landscape, focusing on key considerations for optimizing selection of systemic therapy for advanced breast cancer in older adults. This paper aims to provide evidence-based recommendations and practical guidance for healthcare professionals involved in the care of older adults with breast cancer. By recognizing and addressing the specific needs of older adults, healthcare providers can optimize treatment outcomes and improve the overall quality of care for this population.

Life-Threatening Hematoma in an Elderly Breast Cancer Patient Undergoing Chemotherapy

The use of neoadjuvant chemotherapy in older patients is increasing. However, chemotherapy should be administered considering the medical comorbidities of the patients and the toxicity of chemotherapeutic agents. Here, we present a case of abdominal wall hematoma with spontaneous inferior epigastric artery injury caused by coughing in a 70-year-old woman who was treated with neoadjuvant chemotherapy. Abdominal computed tomography demonstrated an abdominal wall hematoma with active bleeding. However, angiography with selective embolization of the right inferior epigastric artery and the right internal mammary artery was performed successfully. Scheduled chemotherapy was discontinued over concerns of rebleeding and breast-conserving surgery was performed. When deciding on chemotherapy for older patients, attention should be paid to the various complications.

Influence of age on pharmacokinetics of capecitabine and its metabolites in older adults with cancer: a pilot study

BACKGROUND

Capecitabine is an oral chemotherapy prodrug of 5-fluorouracil (5-FU) with unpredictable toxicity, especially in older adults. The aim of this study was to evaluate the pharmacokinetics (PK) of capecitabine and its metabolites in younger adults (< 70 years) and older adults (≥ 70 years) receiving capecitabine for solid cancer.

METHODS

Eligible participants receiving capecitabine had 2 venous samples collected on day 14 of cycle 1 and cycle 2 of their treatment. Capecitabine and metabolite concentrations were determined using liquid chromatography with tandem mass spectrometry. A Bayesian estimation approach was used to generate individual estimates of PK parameters for 5-FU. A linear mixed-effect analysis of variance (ANOVA) model was used to compare dose-normalised log-transformed PK parameters between age groups. Correlations were determined by linear regression and logistic regression analyses.

RESULTS

Of the total 26 participants, 58% were male with a median age of 67 years (range, 37-85) with 54% aged < 70 years and 46% aged ≥ 70 years. Participants aged ≥ 70 years, compared to those aged < 70 years, had a greater 5-FU exposure based on area under the concentration-time curve (AUC) of 17% (90% CI 103-134%; 0.893 vs. 0.762 mg h/L) and 14% increase in maximal concentration, C_max (90% CI 82.1-159%; 0.343 vs. 0.300 mg/L). The 5-FU C_max was positively associated with time up and go (TUG) (Pearson's correlation 0.77, p = 0.01), but not other geriatric assessment domains or severe toxicity.

CONCLUSION

5-FU exposure was significantly increased in older adults compared to younger adults receiving equivalent doses of capecitabine, and is a possible cause for increased toxicity in older adults.

Tolerance and Outcomes of Neoadjuvant Chemotherapy in Geriatric Breast Cancer Patients

INTRODUCTION

Neoadjuvant chemotherapy (NAC) is an established treatment option for patients with human epidermal growth factor receptor 2-positive (Her2+) or triple-negative breast cancer (TNBC). However, the toxicities associated with NAC may lead to reduced tolerance in geriatric patients due to medical comorbidities. Our objective is to evaluate the tolerance and outcomes of NAC in geriatric patients with TNBC and Her2+ breast cancer.

MATERIALS AND METHODS

An institutional review board approved, retrospective study of 43 geriatric (≥70 y) and 103 non-geriatric (<70 y) patients with TNBC and Her2+ breast cancer was conducted. Demographic, comorbidity, treatment, and toxicity variables were collected. Log-rank tests and Cox regression visualized survival outcomes evaluated associations with clinical and demographic variables. Descriptive statistics were performed.

RESULTS

Following NAC, 30% geriatric patients had a pathologic complete response in the primary tumor, 54% had a partial response, and 16% had no response. Of the non-geriatric patients, 24% had a pathologic complete response, 64% had a partial response, and 12% showed no response. NAC-associated toxicities occurred in 81% of geriatric patients and 73% non-geriatric patients, with neutropenia occurring most frequently in both groups. Dose reduction and early discontinuation of NAC each occurred more frequently in the geriatric group (14%; 23%) than the non-geriatric group (7%; 6%). Higher post-treatment Eastern Cooperative Oncology Group scores were associated with worse overall survival and worse recurrence-free survival in both groups.

CONCLUSIONS

NAC was associated with reduced tumor and nodal stage in most geriatric patients; however, NAC-associated toxicities were common and led some patients to reduce or stop their NAC regimen prematurely.

Phase II study of neratinib in older adults with HER2 amplified or HER2/3 mutated metastatic breast cancer

OBJECTIVE

The tolerability and efficacy of targeted therapy in older adults with cancer has not been adequately studied. Neratinib is a novel HER1, HER2, HER4 tyrosine kinase inhibitor that has recently been granted FDA approval for treatment of breast cancer. The major toxicity of neratinib is diarrhea, which affects up to 90% of patients. This phase II trial evaluates the safety and tolerability of neratinib in adults ≥60.

METHODS

Patients aged 60 or older with histologically proven metastatic breast cancer and HER2 amplification (defined by ASCO/CAP guideline) or HER2/HER3 activating mutation were enrolled to receive neratinib at 240 mg daily in 28-day cycles. The association between tolerability, defined as dose reduction and number of completed courses, and log2 Cancer and Aging Research Group (CARG) toxicity risk score was assessed using a Student's t-test and linear regression, respectively. Response rate, progression free survival, and overall survival were also evaluated.

RESULTS

25 patients were enrolled with median age of 66 (range 60-79). Seventy-six percent of patients were white, 16% Asian, and 8% African-American. Seventy-six percent were patients with hormone receptor (HR) positive metastatic breast cancer (MBC) and 24% were patients with HR negative MBC. Median number of prior lines of metastatic therapy were 3 (range 0-11). 20/25 (80%) had worst grade toxicities ≥2. A total of 9/25 (36%) had grade 3 toxicities including 5/20 (20%) diarrhea, 2/20 (8%) vomiting, and 2/20 (8%) abdominal pain. There were no grade 4 or 5 toxicities. A total of 9/25 (36%) had dose reduction, and 2/25 (8%) discontinued therapy due to toxicity. The association between dose reductions and CARG toxicity score reached borderline statistical significance suggesting a trend with participants with higher CARG toxicity risk scores being more likely to require a dose modification (p = 0.054). 1/25 (4%) had a partial response, 11/25 (44%) had stable disease, 12/25 (48%) had progression of disease, and 1/25 (4%) was not assessed. Median progression free survival (PFS) was 2.6 months (95% CI [2.56-5.26]), and median overall survival (OS) was 17.4 months (95% CI [10.3, NA]).

CONCLUSIONS

Neratinib was safe in this population of older adults with HER2 amplified or HER2/3 mutated metastatic breast cancer (BC). Higher CARG toxicity risk score may be associated with greater need for dose adjustments. Future studies are needed to confirm this finding.

Anthracycline-related cardiotoxicity in older patients with acute myeloid leukemia: a Young SIOG review paper

The incidence of acute myeloid leukemia (AML) increases with age. Intensive induction chemotherapy containing cytarabine and an anthracycline has been part of the upfront and salvage treatment of AML for decades. Anthracyclines are associated with a significant risk of cardiotoxicity (especially anthracycline-related left ventricular dysfunction [ARLVD]). In the older adult population, the higher prevalence of cardiac comorbidities and risk factors may further increase the risk of ARLVD. In this article of the Young International Society of Geriatric Oncology group, we review the prevalence of ARLVD in patients with AML and factors predisposing to ARLVD, focusing on older adults when possible. In addition, we review the assessment of cardiac function and management of ARLVD during and after treatment. It is worth noting that only a minority of clinical trials focus on alternative treatment strategies in patients with mildly declined left ventricular ejection fraction or at a high risk for ARLVD. The limited evidence for preventive strategies to ameliorate ARLVD and alternative strategies to anthracycline use in the setting of cardiac comorbidities are discussed. Based on extrapolation of findings from younger adults and nonrandomized trials, we recommend a comprehensive baseline evaluation of cardiac function by imaging, cardiac risk factors, and symptoms to risk stratify for ARLVD. Anthracyclines remain an appropriate choice for induction although careful risk-stratification based on cardiac disease, risk factors, and predicted chemotherapy-response are warranted. In case of declined left ventricular ejection fraction, alternative strategies should be considered.

Applications and challenges in therapeutic drug monitoring of cancer treatment: A review

Most anticancer agents show wide variability in pharmacokinetics (PK) and have a narrow therapeutic index which makes fixed dosing suboptimal. To achieve the best therapeutic outcomes with these agents, many studies have postulated using PK or therapeutic drug monitoring (TDM)-guided dosing. However, multiple factors contribute to the variability in PKs making the application of TDM in practice challenging. Also, despite the known association with clinical outcomes, standard guidelines on PK-guided dosing are lacking for most agents. Understanding the factors that contribute to PK variability and their impact is essential for dose individualization. The purpose of this review is to discuss the factors that contribute to the PK variability of anticancer agents and the challenges faced in practice when individualizing doses for certain widely used agents. Searching the literature has identified several gaps and efforts are needed to ensure better targeting of cancer therapeutics.

Older adults in hematologic malignancy trials: Representation, barriers to participation and strategies for addressing underrepresentation

Despite a high incidence of hematologic malignancies in older adults, available data indicate that there is disproportionately low representation of adults ≥65 years with hematologic malignancies (greater in patients ≥75 years) in clinical trials. Biological and clinical differences between older and younger adults and diversity within older patients necessitate adequate representation of the older subpopulation in hematologic malignancy trials. This would allow trial results to be generalizable and inform treatment decisions in the older patient population. Restrictive eligibility criteria may be barriers to adequate representation, as older adults do not typically meet these criteria. Efforts to broaden eligibility criteria in clinical trials have been proposed and may promote enrollment of a representative older population with hematologic malignancies. Collaboration among a diverse group of stakeholders will be needed to implement current proposals and evaluate their impact on increasing representation of older adults in trials evaluating therapies for hematologic malignancies.

Utilisation of Adjuvant Chemotherapy and 5-Year Survival Analysis of Prospectively Recorded Cohort Data for Older Adults Versus Younger Adults with Resected Primary Colon Cancer

PURPOSE

Colon cancer is predominantly a disease of older adults. Studies determining the influence of age on outcomes of colon cancer have conflicting results. We aim to determine the long-term outcomes and utilisation of adjuvant chemotherapy of older adults compared with younger adults who had had a resection of a primary colon cancer.

METHODS

Consecutive patients who had resection of a primary colon cancer between January 1, 2000 and December 31, 2010 were identified from a prospective database and stratified into three age groups: ≤ 69 years, 70 to 79 years, and ≥ 80 years. Age-related differences in patients, cancer, and treatment characteristics were determined by chi-square tests. Five-year overall survival and cancer-specific survival were determined by Kaplan-Meier method and by multivariable Cox regression analysis to adjust for potential confounding factors.

RESULTS

Of 1135 included patients, 469 (41%) patients were aged ≤ 69 years, 382 (34%) were 70-79 years, and 284 (25%) were ≥ 80 years. Increasing age group predicted more comorbidity (p < 0.001), cardiac comorbidity (p < 0.001), right-sided cancers (p < 0.001), and less adjuvant chemotherapy (stage III only; p < 0.001). Increasing age group was associated with worse overall survival by stage (p < 0.001) but not cancer-specific survival by stage (p = 0.83). Adjuvant chemotherapy in patients with stage III colon cancer independently predicted improved overall survival (p < 0.001) and cancer-specific survival (p = 0.01).

CONCLUSIONS

Compared with younger adults, older adults with colon cancer had worse survival outcomes and received less adjuvant chemotherapy.

Preventive drugs in the last year of life of older adults with cancer: Is there room for deprescribing?

BACKGROUND

The continuation of preventive drugs among older patients with advanced cancer has come under scrutiny because these drugs are unlikely to achieve their clinical benefit during the patients' remaining lifespan.

METHODS

A nationwide cohort study of older adults (those aged ≥65 years) with solid tumors who died between 2007 and 2013 was performed in Sweden, using routinely collected data with record linkage. The authors calculated the monthly use and cost of preventive drugs throughout the last year before the patients' death.

RESULTS

Among 151,201 older persons who died with cancer (mean age, 81.3 years [standard deviation, 8.1 years]), the average number of drugs increased from 6.9 to 10.1 over the course of the last year before death. Preventive drugs frequently were continued until the final month of life, including antihypertensives, platelet aggregation inhibitors, anticoagulants, statins, and oral antidiabetics. Median drug costs amounted to $1482 (interquartile range [IQR], $700-$2896]) per person, including $213 (IQR, $77-$490) for preventive therapies. Compared with older adults who died with lung cancer (median drug cost, $205; IQR, $61-$523), costs for preventive drugs were higher among older adults who died with pancreatic cancer (adjusted median difference, $13; 95% confidence interval, $5-$22) or gynecological cancers (adjusted median difference, $27; 95% confidence interval, $18-$36). There was no decrease noted with regard to the cost of preventive drugs throughout the last year of life.

CONCLUSIONS

Preventive drugs commonly are prescribed during the last year of life among older adults with cancer, and often are continued until the final weeks before death. Adequate deprescribing strategies are warranted to reduce the burden of drugs with limited clinical benefit near the end of life.

Modeling individual time courses of thrombopoiesis during multi-cyclic chemotherapy

Background

Thrombocytopenia is a major side-effect of cytotoxic cancer therapies. The aim of precision medicine is to develop therapy modifications accounting for the individual’s risk.

Methodology/Principle findings

To solve this task, we develop an individualized bio-mechanistic model of the dynamics of bone marrow thrombopoiesis, circulating platelets and therapy effects thereon. Comprehensive biological knowledge regarding cell differentiation, amplification, apoptosis rates, transition times and corresponding regulations are translated into ordinary differential equations. A model of osteoblast/osteoclast interactions was incorporated to mechanistically describe bone marrow support of quiescent cell stages. Thrombopoietin (TPO) as a major regulator is explicitly modelled including pharmacokinetics and–dynamics of TPO injections. Effects of cytotoxic drugs are modelled by transient depletions of proliferating cells.

To calibrate the model, we used population data from the literature and close-meshed individual data of N = 135 high-grade non-Hodgkin’s lymphoma patients treated with CHOP-like chemotherapies. To limit the number of free parameters, several parsimony assumptions were derived from biological data and tested via Likelihood methods. Heterogeneity of patients was explained by a few model parameters. The over-fitting issue of individual parameter estimation was successfully dealt with a virtual participation of each patient in population-based experiments.

The model qualitatively and quantitatively explains a number of biological observations such as the role of osteoblasts in explaining long-term toxic effects, megakaryocyte-mediated feedback on stem cells, bi-phasic stimulation of thrombopoiesis by TPO, dynamics of megakaryocyte ploidies and non-exponential platelet degradation. Almost all individual time series could be described with high precision. We demonstrated how the model can be used to provide predictions regarding individual therapy adaptations.

Conclusions

We propose a mechanistic thrombopoiesis model of unprecedented comprehensiveness in both, biological mechanisms considered and experimental data sets explained. Our innovative method of parameter estimation allows robust determinations of individual parameter settings facilitating the development of individual treatment adaptations during chemotherapy.

Chemotherapy is ubiquitously used to treat cancer diseases. Due to general toxicity of the drugs, chemotherapy results in a number of side effects especially with respect to blood formation. Here we study the loss of platelets during chemotherapy which is dose limiting in many situations. However, this side-effect greatly varies between patients with respect to both, severity and necessity of clinical countermeasures.We therefore developed a mathematical model to predict the time course of platelets of patients under chemotherapy and to propose possible treatment adaptations in cases of intolerable toxicity. The model is based on available biological knowledge and data of platelet formation and therapeutic effects thereon. As a major result, we could describe individual time series data of 135 patients under chemotherapy. Conversely, the model can be used to make predictions regarding alternative therapy schedules such as postponement of therapy or chemotherapy dose reductions. Our model is intended to support clinical decision making on an individual patient level.

Outcome after neoadjuvant chemotherapy in elderly breast cancer patients - a pooled analysis of individual patient data from eight prospectively randomized controlled trials

INTRODUCTION

Recent studies showed the high and independent impact of age (<40 years) on pathologic complete response (pCR) and prognosis for patients undergoing neoadjuvant chemotherapy (NACT). Some physicians might not consider elderly patients (>65 years) for NACT due to poor prognosis or higher toxicity. The aim of this analysis is to help selecting appropriately elderly women who would benefit from NACT. Secondly, survival parameters are investigated in several histological subgroups.

METHODS

From 1998 to 2010, eight prospectively randomized German Breast Group (GBG) trials of anthracycline- and taxane-based NACT were performed and analyzed in this study.

RESULTS

Compared to the overall average, elderly women had significant larger tumors and more overall lymph node involvement. Histologically, they had more G2 tumors, more estrogen-receptor positive tumors. pCR (ypT0 ypN0) was strongly associated with age. The multivariable logistic regression analysis of clinical parameters showed that young age, clinical stage T4, invasive ductal cancer and poor differentiated breast cancer are predictive for high pCR. The multivariate analyses of molecular subgroups showed that age >65years is a predictor of significant lower pCR in HER2- breast cancers. Nonetheless, HER2+ patients showed pCR rates as high- and HR+/HER2+ even higher - pCR rates compared to younger patients.

DISCUSSION

This study underlines the unfavorable impact of higher age on pCR, but it shows a realistic chance for pCR if NACT is applied - especially for HER2+ patients. Furthermore, elderly patients with non-TNBC showed a good prognosis (comparable to younger patients) regarding overall survival, even if they do not have pCR.

Systemic Combination Chemotherapy in Elderly Pancreatic Cancer: a Review

PURPOSE

In recent years, significant progress in survival has been achieved using systemic combination chemotherapy in patients with pancreatic cancer. However, the elderly are largely underrepresented in clinical trials, and gains made from these may not necessarily apply to this important subgroup of patients. We review the currently available data regarding contemporary combination chemotherapy regimens, including FOLFIRINOX, gemcitabine plus nab-paclitaxel, nanoliposomal irinotecan plus 5-fluorouracil and leucovorin, and gemcitabine plus capecitabine, in elderly pancreatic cancer patients.

METHODS

We performed a search of Pubmed using the terms "pancreatic cancer", "elderly", "FOLFIRINOX", "gemcitabine", "nab-paclitaxel", "capecitabine", and "nanoliposomal irinotecan" and included articles investigating the use of combination chemotherapy in the elderly with pancreatic adenocarcinoma. Relevant abstracts from American Society of Clinical Oncology and European Society of Medical Oncology meetings were included.

RESULTS

Current clinical evidence and experience suggests that relatively fit elderly pancreatic cancer patients may derive significant benefit from contemporary combination chemotherapy regimens. Strategies to improve tolerability without decreasing efficacy include dose reduction, schedule modification, and growth factor support. Phase III clinical trials are ongoing to determine the optimal use of combination chemotherapy regimens in elderly patients with pancreatic cancer.

CONCLUSION

Identifying elderly patients who will benefit from combination chemotherapy for pancreatic cancer remains a significant clinical challenge. An assessment of medical comorbidities and functional status plays a key role in determining fitness for intensive chemotherapeutic regimens in this important subset of patients.

Novel Strategies on Personalized Medicine for Breast Cancer Treatment: An Update

Breast cancer is the most common cancer type among women worldwide. With breast cancer patients and survivors being reported to experience a repertoire of symptoms that are detrimental to their quality of life, the development of breast cancer treatment strategies that are effective with minimal side effects is therefore required. Personalized medicine, the treatment process that is tailored to the individual needs of each patient, is recently gaining increasing attention for its prospect in the development of effective cancer treatment regimens. Indeed, recent studies have identified a number of genes and molecules that may be used as biomarkers for predicting drug response and severity of common cancer-associated symptoms. These would provide useful clues not only for the determination of the optimal drug choice/dosage to be used in personalized treatment, but also for the identification of gene or molecular targets for the development of novel symptom management strategies, which ultimately would lead to the development of more personalized therapies for effective cancer treatment. In this article, recent studies that would provide potential new options for personalized therapies for breast cancer patients and survivors are reviewed. We suggest novel strategies, including the optimization of drug choice/dosage and the identification of genetic changes that are associated with cancer symptom occurrence and severity, which may help in enhancing the effectiveness and acceptability of the currently available cancer therapies.

Phase I dose-finding study of eribulin and capecitabine for metastatic breast cancer: JBCRG-18 cape study

Background

Eribulin is a nontaxane microtubule inhibitor with activity in patients with metastatic breast cancer (MBC). We conducted a phase I dose-finding study of eribulin and capecitabine in patients with MBC pretreated with anthracycline and taxane.

Methods

Women with MBC aged ≤70 years were enrolled. A 3 + 3 dose escalation design was used: level 0 dosing, eribulin (1.4 mg/m² intravenously on days 1 and 8) plus capecitabine [825 mg/m² orally twice daily (BID)]; 2-weeks-on, 1-week-off in a 21-day cycle. If there were no dose-limiting toxicities (DLTs), level 1 capecitabine dose was 1000 mg/m² BID. The primary objective was to determine maximum tolerated dose, DLTs, and recommended dose (RD). Secondary objectives included pharmacokinetics, safety, and best overall response rate.

Results

Nine women with MBC were enrolled; six at level 0, three at level 1. One patient had grade 4 DLTs at level 0 (serum creatinine 7.65 mg/dL and uric acid 13.4 mg/dL), considered associated with study drugs. Level 1 dosing was taken as the RD. Neutropenia was the most common ≥grade 3 toxicity. Pharmacokinetic parameters of eribulin were not influenced by co-administration of capecitabine. Of three patients in level 1, one achieved partial response and one had prolonged stable disease.

Conclusion

Eribulin with capecitabine in the level 1 dosing schedule was associated with manageable toxicities and promising clinical activity. This combination is recommended for phase II investigation.

Electronic supplementary material

The online version of this article (doi:10.1007/s12282-017-0798-4) contains supplementary material, which is available to authorized users.

Safety and effectiveness of eribulin in Japanese patients with locally advanced or metastatic breast cancer: a post-marketing observational study

Background This large-scale study was conducted to evaluate the safety and effectiveness of eribulin for the treatment of inoperable or recurrent breast cancer in real-world settings in Japan. Methods Between July and December 2011, eligible patients with inoperable or recurrent breast cancer receiving eribulin for the first time were centrally registered and observed for 1 year. Eribulin was administered intravenously (1.4 mg/m²) on days 1 and 8 of every 3-week cycle. The primary endpoint was the frequency and intensity of adverse drug reactions (ADRs). Secondary endpoints included overall response rate (ORR) and time to treatment failure (TTF). Results Of 968 patients registered at 325 institutions, 951 and 671 were included in the safety and effectiveness analyses, respectively. In the safety population, ADRs were observed in 841 patients (88.4%). The most common (≥15% incidence) were neutropenia (66.6%), leukopenia (62.4%), lymphopenia (18.4%), and peripheral neuropathy (16.8%). The most common grade ≥ 3 ADRs (>5% incidence) were neutropenia (59.8%), leukopenia (50.5%), lymphopenia (16.1%), and febrile neutropenia (7.7%). In the effectiveness population, ORR was 16.5% (95% confidence interval: 13.7, 19.4). The median TTF was 127 days (95% confidence interval: 120, 134). Conclusions The safety and effectiveness profile of eribulin was consistent with prior studies. Eribulin had a favorable risk-benefit balance when used in real-world clinical settings.