Effects Of Eribulin Research Articles

Efficacy and safety of eribulin plus gemcitabine in second-line or beyond for patients with HER2-negative metastatic breast cancer (MBC): A multicenter, open-label, single-arm, phase II study.

e13139 Background: The combination of eribulin and gemcitabine has demonstrated a similar progression-free survival (PFS) benefit as paclitaxel plus gemcitabine, with less neurotoxicity, for patients with MBC who have not received prior cytotoxic chemotherapy. However, the effect of eribulin plus gemcitabine on PFS in second line or beyond remains unclear. Methods: This open-label, single-arm, phase II study (NCT05263882) was conducted at 14 institutions in China. Eligible patients had histologically confirmed HER2-negative MBC and had received at least one prior taxane-containing chemotherapy regimen for advanced disease, and anthracycline-containing regimens in the adjuvant setting. Patients received intravenous infusions of eribulin (1.4 mg/m2) and gemcitabine (1.0 g/m2) on days 1 and 8 of a 21-day cycle. Efficacy outcomes, including PFS, objective response rate (ORR), and disease control rate (DCR), were assessed using RECIST v1.1. Adverse events (AEs) were graded according to NCI-CTC version 5.0. Results: A total of 70 patients were enrolled from November 2021 to October 2023; 47 (71.4%) had HR+HER2- and 18 (28.6%) had triple-negative MBC. The median patient age was 50 years (range: 31-68), and the sites of metastasis were the bone (68.6%), liver (52.9%), lymph nodes (48.6%), lung (44.3%) and brain (10.0%). Patients had received a median of 3 prior lines of systemic treatment, 2 lines of chemotherapy, and 1 line of endocrine treatment. Among all patients, the ORR was 48.6%, the DCR was 92.9% and the median PFS was 7.2 months. For the HR-positive subgroup, the median PFS was 8.4 months, while for the triple-negative subgroup, it was 6.3 months. Among HR+ patients who had received prior CDK4/6 inhibitor treatment, the median PFS was 7.2 months. In the subgroup of HR+ patients who had not received CDK4/6 inhibitor treatment, the median PFS had not been reached. For the HR+ HER2-low subgroup, the median PFS was 8.4 months. The most common grade 3-4 AEs were hematological, including neutropenia (38.6%), leukopenia (31.4%), anemia (24.3%), and thrombocytopenia (15.7%). Grade ≥3 perceived AEs were relatively low. Conclusions: Eribulin plus gemcitabine was effective in heavily pretreated patients with HER2- MBC, while maintaining a predictable and manageable safety profile. Clinical trial information: NCT05263882 . [Table: see text]

Abstract PO3-05-10: Efficacy and safety of eribulin plus gemcitabine in second-line or beyond for patients with HER2-negative metastatic breast cancer (MBC): A multi-center, open-label, single-arm, phase II study

Abstract Background: Eribulin is a halichondrin non-taxane inhibitor of microtubule dynamics approved in China for advanced breast cancer patients who have received at least two prior chemotherapy treatments. The combination of eribulin and gemcitabine has demonstrated a similar progression-free survival (PFS) benefit as paclitaxel plus gemcitabine, with less neurotoxicity, for patients with MBC who have not received prior cytotoxic chemotherapy. However, the effect of eribulin plus gemcitabine on PFS in second line or beyond remains unclear. Methods: This open-label, single-arm, phase II study (NCT05263882) was conducted at 13 institutions in China. Eligible patients had histologically confirmed HER2-negative MBC and had received at least one prior taxane-containing chemotherapy regimen for advanced disease, and anthracycline-containing regimens in the adjuvant setting. Patients received intravenous infusions of eribulin (1.4 mg/m2) and gemcitabine (1.0 g/m2) on days 1 and 8 of a 21-day cycle. Efficacy outcomes, including PFS, objective response rate (ORR), and disease control rate (DCR), were assessed using RECIST v1.1. Adverse events (AEs) were graded according to NCI-CTC version 5.0. Results: A total of 65 patients were enrolled from November 2021 to May 2023; 47 (72.3%) had HR+/HER2- and 18 (27.7%) had triple-negative MBC. The median patient age was 50 years (range: 31-68), and the sites of metastasis were the bone (70.8%), liver (58.5%), lymph nodes (50.8%), lung (43.1%) and brain (10.8%). Patients had received a median of 3 prior lines of systemic treatment, 2 lines of chemotherapy, and 1 line of endocrine treatment. Among all patients, the ORR was 52.3%, the DCR was 92.3% and the median PFS was 7.6 months (Table). For the HR-positive subgroup, the median PFS was 8.4 months, while for the triple-negative subgroup, it was 7.6 months. Among patients who had received prior CDK4/6 inhibitor treatment, the median PFS was 7.2 months. In the subgroup of patients who had not received CDK4/6 inhibitor treatment, the median PFS had not been reached. The most common grade 3-4 AEs were hematological, including neutropenia (41.6%), leukopenia (33.9%), anemia (23.1%), and thrombocytopenia (15.4%). No grade ≥3 perceived AEs were reported. Conclusion: Eribulin plus gemcitabine was effective in heavily pretreated patients with HER2- MBC, while maintaining a predictable and manageable safety profile. Table. Summary of efficacy outcomes Citation Format: PeiJian Peng, Xiao-Lu Xu, Jin-Cai Zhong, Jin-Hui Ye, Zhi-Hui Wang, Hong Wang, Hong Lin, Cai-Wen Du, Guorong Zou, Jie Ouyang, Ying-Ying Shi, Fei Xu, Geng-Sheng Yu, Yong-Kui Lu, Yong-Xia Wang, Shi-En Cui, Lu-Zhen Li. Efficacy and safety of eribulin plus gemcitabine in second-line or beyond for patients with HER2-negative metastatic breast cancer (MBC): A multi-center, open-label, single-arm, phase II study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-05-10.

Involvement of ferroptosis in eribulin-induced cytotoxicity in ovarian clear cell carcinoma

Ovarian clear cell carcinoma (OCCC) is a unique clinicopathological subtype of epithelial ovarian cancer that is resistant to standard chemotherapy. Eribulin, a microtubule dynamics inhibitor of halichondrin class, has unique effects in the cancer microenvironment such as induction of epithelization and reduction in metastatic potential in breast cancer cells; however, nothing is known about the effect of eribulin and the detailed mechanisms in OCCC. This study aimed to investigate the involvement of ferroptosis and its mechanism in the antitumor activity of eribulin in OCCC cells and a mouse xenograft model. We found that eribulin-induced cell death was reduced by ferroptosis inhibitors; deferoxamine, an iron chelator and ferrostatin-1, a lipid peroxidation inhibitor. Eribulin increased the levels of intracellular iron, reactive oxygen species (ROS), and lipid peroxides, and increased the mitochondrial membrane potential. Eribulin downregulated the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), the mitochondrial enzyme dihydroorotate dehydrogenase (DHODH), and superoxide dismutase (SOD) activity. The combination of eribulin and ML210, a glutathione peroxidase 4-inhibiting ferroptosis inducer, had a synergistic effect on ferroptosis. Taken together, our findings show firstly that eribulin triggers ferroptosis in OCCC and this effect occurs via the suppression of the Nrf2–HO-1 signaling pathway, SOD activity and the promotion of lipid peroxidation. These findings suggest that eribulin-induced ferroptosis is associated with its anti-tumor effect and also could be a potential therapeutic target in OCCC.

Effects of Eribulin on the RNA Content of Extracellular Vesicles Released by Metastatic Breast Cancer Cells.

Extracellular vesicles (EVs) are small lipid particles secreted by almost all human cells into the extracellular space. They perform the essential function of cell-to-cell communication, and their role in promoting breast cancer progression has been well demonstrated. It is known that EVs released by triple-negative and highly aggressive MDA-MB-231 breast cancer cells treated with paclitaxel, a microtubule-targeting agent (MTA), promoted chemoresistance in EV-recipient cells. Here, we studied the RNA content of EVs produced by the same MDA-MB-231 breast cancer cells treated with another MTA, eribulin mesylate. In particular, we analyzed the expression of different RNA species, including mRNAs, lncRNAs, miRNAs, snoRNAs, piRNAs and tRNA fragments by RNA-seq. Then, we performed differential expression analysis, weighted gene co-expression network analysis (WGCNA), functional enrichment analysis, and miRNA-target identification. Our findings demonstrate the possible involvement of EVs from eribulin-treated cells in the spread of chemoresistance, prompting the design of strategies that selectively target tumor EVs.

Eribulin promotes proliferation of CD8+ T cells and potentiates T cell-mediated anti-tumor activity against triple-negative breast cancer cells.

Chemotherapeutic agents exert immunomodulatory effects on triple-negative breast cancer (TNBC) cells and immune cells. Eribulin favorably affects the immunological status of patients with breast cancer. However, the effects of eribulin on the immune cells remain unexplored. The aim of this study was to investigate the effects of eribulin on immune cells. Peripheral blood mononuclear cells (PBMCs) from healthy donors and mouse splenocytes were stimulated with anti-CD3 and anti-CD28 antibodies. The effects of eribulin and paclitaxel on cell proliferation and differentiation status were analyzed using flow cytometry. RNA sequencing was performed to assess alterations in gene expression in CD8+ T cells following eribulin and paclitaxel treatment. Using TNBC cell lines (MDA-MB-231, Hs578T, and MDA-MB-157), the anti-tumor activity of CD3/CD28-stimulated T cells combined with eribulin or paclitaxel was evaluated. Eribulin did not affect CD3/CD28-stimulated PBMCs proliferation. However, eribulin significantly decreased the CD4/CD8 ratio in T cells, indicating that eribulin facilitates CD8+ T cell proliferation. Furthermore, eribulin significantly increased the frequency of less differentiated CD45RA+, CCR7+, and TCF1+ subsets of CD8+ T cells. RNA sequencing revealed that eribulin enhanced the expression of gene sets related to cell proliferation and immune responses. Moreover, eribulin augmented the anti-tumor effects of CD3/CD28-stimulated T cells against TNBC cells. These results were not observed in experiments using paclitaxel. Eribulin promoted CD8+ T cell proliferation, repressed effector T cell differentiation, and harnessed T cell-mediated anti-tumor effects. These mechanisms may be one of the cues that eribulin can improve the immunological status of tumor-bearing hosts.

Efficacy and safety of eribulin plus gemcitabine in second-line or beyond for patients with HER2-negative metastatic breast cancer: A multi-center, open-label, single-arm, phase II study.

e13102 Background: Eribulin is a non-taxane microtubule inhibitor approved in China for the treatment of patients with advanced breast cancer who progress after ≥2 lines of chemotherapy. Eribulin was shown to improve overall survival (OS) in various subgroups of patients with metastatic breast cancer (MBC) who were pretreated with an anthracycline and taxane. Furthermore, combination chemotherapy with eribulin plus gemcitabine led to a similar progression free-survival (PFS) benefit, with less neurotoxicity, as paclitaxel plus gemcitabine in patients with MBC who had not received prior cytotoxic chemotherapy for metastatic disease. However, the effect of eribulin plus gemcitabine on PFS in second-line or beyond remain unclear. Methods: This phase II, open-label, single-arm study was conducted at 13 institutions in China (NCT05263882). Patients with histologically confirmed HER2-negative MBC who had received at ≥1 prior taxane-containing chemotherapeutic regimen for advanced disease and had received anthracycline-containing regimens in the adjuvant setting, were enrolled between Nov 2021 and Oct 2022. Eligible patients received eribulin 1.4 mg/m2 and gemcitabine 1.0 g/m2 intravenously on days 1 and 8 of a 21-day cycle. Efficacy outcomes included PFS, objective response rate (ORR), and disease control rate (DCR), evaluated using RECIST v1.1. Adverse events (AEs) were graded according to The National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 5.0. Results: In total, 54 patients were included; 39 (72.2 %) were HR+/HER2- and 15 (27.8 %) were triple negative, the median age was 49.5 years (range: 31-70) and sites of metastasis were the liver (57.4%), lung (37.0%), bone (59.3%), brain (11.1%) and lymph nodes (53.7%). The median number of previous chemotherapy lines was 3 (range: 2-7): eribulin plus gemcitabine was used in second-line for 15 (27.8%) patients, third-line for 20 (37.0%) patients, fourth-line for 7 (13.0%) patients and ≥fifth-line in 12 (22.2%) patients. The median PFS was 7.7 months. The ORR was 40.7% and the DCR was 66.7%. Best overall responses and PFS rates at 3 and 6 months are shown. The most common grade 3-4 AEs were hematological: Leukopenia (35.2%), anemia (18.6%) and thrombocytopenia (9.4%). No treatment-related death was reported. Conclusions: Eribulin plus gemcitabine is effective in heavily pretreated patients with HER2-negative MBC with a predictable, manageable safety profile. Clinical trial information: NCT05263882 . [Table: see text]

Predictive value of peripheral blood markers in soft tissue sarcoma patients treated with eribulin.

eribulin, an anticancer agent that inhibits microtubule growth, along with trabectedin and pazopanib, has been approved for the treatment of advanced soft tissue sarcoma (STS). However, there has been no consensus on the optimal second-line therapy among these three agents following treatment failure with doxorubicin. Recently, the effects of eribulin on the tumor microenvironment and immunity have been reported in breast cancer, and peripheral blood immune markers have also been reported to be a predictor of eribulin efficacy, though this remains unverified in STS. We aimed to evaluate the predictive value of various peripheral blood immune markers in STS patients treated with eribulin. we retrospectively reviewed the medical records of STS patients treated with eribulin and examined whether peripheral blood immune markers at different time points could be prognostic factors for STS patients treated with eribulin. several peripheral blood immune markers were significantly associated with progression-free survival (PFS), specifically neutrophil-to-lymphocyte ratio (NLR) prestart (NLR before the initial administration of eribulin) (P=0.019) and absolute lymphocyte count (ALC)8D (ALC on Day 8 of the first administration of eribulin) (P=0.037). NLR prestart (P=0.001) was significantly associated with overall survival. The combination of NLR prestart and ALC8D determined the PFS of STS patients treated with eribulin. the combined indicator of low NLR prestart and high ALC8D predicted the survival of patients treated with eribulin as well as the histology of L-sarcoma. Though further validation was needed, this finding would provide valuable prognostic factor that help treatment decision in the absence of consensus on the optimal second-line therapy following doxorubicin treatment in STS patients.

Abstract P4-07-19: Eribulin enhances STING-dependent induction of type I interferons in immune and triple-negative breast cancer cells

Abstract Triple-negative breast cancer (TNBC) is a heterogenous subtype of breast cancer that lacks effective targeted treatment options. However, TNBC typically has a higher mutational burden and greater degree of immunogenicity than other breast tumors, making immunotherapy a viable strategy for effective treatment of this disease. Strategies to improve the response of TNBC patients to immunotherapy include the upregulation of the cGAS-STING innate immune sensing pathway and STING agonists are in clinical development for the treatment of TNBC. We demonstrate that eribulin, a microtubule destabilizer currently used in the treatment of TNBC, functions as an indirect STING agonist because it promotes the release of mitochondrial DNA into the cytoplasm. Eribulin also enhances type I interferon expression induced by STING agonists through a second TBK1-dependent mechanism downstream of STING activation that is shared by the RIG/MAVS RNA sensing pathway. Both mechanisms of eribulin-mediated activation of interferon expression occur in immune and TNBC cells and are shared with other microtubule destabilizers, including vinorelbine, but not with the microtubule stabilizing agent paclitaxel. These effects of eribulin on innate immune sensing pathways in vitro prompted further evaluations of the impact of eribulin on the in vivo immunological response to mammary tumors. We found that eribulin, but not paclitaxel, promotes the activation of CD4+ T-cells in the spleens and draining lymph nodes of tumored animals. This activation required tumor priming but was independent of any direct effect on tumor growth inhibition, demonstrating a specific role of eribulin as a tumor immune modulator. These data contribute to accumulating evidence that there are important mechanistic differences between the microtubule targeted chemotherapeutics currently used in the treatment of TNBC and suggest that eribulin elicits a more favorable innate immunological signature than paclitaxel. Research supported by Eisai Inc. Citation Format: Leila Takahashi-Ruiz, Charles Fermaintt, Nancy Wilkinson, Susan Mooberry, April Risinger. Eribulin enhances STING-dependent induction of type I interferons in immune and triple-negative breast cancer cells [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-19.

Abstract P4-01-15: Eribulin treatment for hormone receptor positive breast cancer cells with resistant to endocrine therapy promotes re-expression of estrogen receptor

Abstract Background: The development of resistance to endocrine therapy appears to have become a major clinical problem of hormone receptor (HR) positive breast cancer. Drug resistance is associated with changes of the tumor microenvironment due to tumor hypoxia. Eribulin, a nontaxane, synthetic microtuble dynamics inhibitor, induces G2/M cell cycle arrest. Interestingly, it also has some unique anticancer effects in breast cancer cells, such as improvement of tumor perfusion and hypoxia. In this study, we investigated the effect of eribulin for endocrine therapy resistant breast cancer. Materials and Methods: We established hypoxia resistant HR positive/human epithelial growth receptor 2 (HER2) negative breast cancer cell lines, via continuous culturing in hypoxic environment. Parental and hypoxia resistant cell lines were treated with eribulin, followed by estrogen receptor (ER), epithelial-mesenchymal transition (EMT) and hypoxia related gene and protein expression changes in each surviving cells by quantitative real-time polymerase chain reaction (qPCR) and western blot, respectively. In addition, proliferation assay was conducted in these breast cancer cell lines treated with tamoxifen alone and tamoxifen plus eribulin. For the in vivo experiment, we produced subcutaneous xenografts of each cell lines. We treated these tumors with tamoxifen alone and tamoxifen plus eribulin, and analyzed their growth activity and protein expression by immunohistochemical study of surgically resected tissues. Results: Though parental HR positive/HER2 negative breast cancer cell lines displayed an epithelial-like cuboidal phenotype, hypoxia resistant cell lines displayed a mesenchymal-like spindle-shaped phenotype. In addition, hypoxia resistant cell lines significantly decreased the expression of epithelial and ER related markers, and exhibited a higher level of resistance to tamoxifen treatment. On the other hand, eribulin treatment for hypoxia resistant cell lines increased epithelial and ER related gene and protein expressions, and enhanced the anticancer effect of tamoxifen. In in vivo xenograft models, eribulin treatment for hypoxia resistant tumor with resistance to tamoxifen induced re-expression of ER. Also, hypoxia resistant tumor after administration of eribulin became effective with tamoxifen treatment. Conclusions: Eribulin improve the tumor microenvironment changed by hypoxia, and induce re-expression of ER in hypoxia resistant breast cancer cells. Eribulin treatment for HR positive breast cancer with resistance to endocrine therapy makes possibility of re-administration of endocrine therapy. Citation Format: Wataru Goto, Shinichiro Kashiwagi, Misato Fujioka, Sae Ishihara, Yuka Asano, Tamami Morisaki, Satoru Noda, Tsutomu Takashima, Masaichi Ohira, Kosei Hirakawa. Eribulin treatment for hormone receptor positive breast cancer cells with resistant to endocrine therapy promotes re-expression of estrogen receptor [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-01-15.

Eribulin improved the overall survival from the initiation of first-line chemotherapy for HER2-negative advanced breast cancer: a multicenter retrospective study

BackgroundEribulin methylate (eribulin) improved the overall survival (OS) of eribulin-treated patients with HER2-negative advanced breast cancer (ABC) in prospective and retrospective studies. However, the effect of eribulin on OS as first-line chemotherapy and the characteristics of the patients who benefited from eribulin remain unclear.MethodsBetween January 2011 and December 2016, 301 patients with HER2-negative ABC who started first-line chemotherapy at 3 institutions were retrospectively evaluated for OS from the initiation of first-line chemotherapy.ResultsWe identified 172 patients (119 estrogen receptor-positive [ER+], 47 ER−, 6 unknown) who received eribulin (eribulin group) and 129 patients (92 ER+, 31 ER−, 6 unknown) who did not receive eribulin (non-eribulin group). The median OS from the initiation of first-line chemotherapy in the two groups was not statistically significant (869 vs. 744 days, P = 0.47, log-rank); however, in patients who received eribulin in later lines (≥3rd-line) and who had a history of perioperative chemotherapy with anthracycline- and/or taxane-based regimens, the median OS improved (1001 vs. 744 days, P = 0.037; and 834 vs. 464 days, respectively P = 0.032, respectively; Wilcoxon). Multivariate analyses revealed that a history of perioperative chemotherapy with anthracycline- and/or taxane-based regimens was a predictive factor (hazard ratio, 0.39; 95% confidence interval, 0.21–0.70) for OS.ConclusionsThis study successfully identified subgroups of HER2− ABC patients with improved OS by eribulin therapy. Selecting patients according to their background and line of treatment will maximize the efficacy of eribulin therapy.

Stathmin participates in antiproliferative effects of eribulin in leiomyosarcoma cells

Stathmin participates in antiproliferative effects of eribulin in leiomyosarcoma cells

Effectiveness of combination with eribulin in third line of chemotherapy for triple negative breast cancer (case report)

In most cases triple negative breast cancer is characterized by an aggressive course of disease and early development of resistance to chemotherapy. Thereafter, the late-line treatment choice, usually after anthracyclines and taxanes, is problematic due to the limited amount of effective and low-toxic cytostatics. In our opinion, in this situation the use of eribulin which possesses unique antitumor action mechanisms is a good option. An illustrative case of a pronounced antitumor effect of eribulin in metastatic breast cancer with triple negative phenotype resistant to previous lines of chemotherapy is presented.

Eribulin activity in soft tissue sarcoma monolayer and three-dimensional cell line models: could the combination with other drugs improve its antitumoral effect?

BackgroundEribulin has shown antitumour activity in some soft tissue sarcomas (STSs), but it has only been approved for advanced liposarcoma (LPS).MethodsIn this study, we evaluated the effect of eribulin on proliferation, migration and invasion capabilities in LPS, leiomyosarcoma (LMS) and fibrosarcoma (FS) models, using both monolayer (2D) and three-dimensional (3D) spheroid cell cultures. Additionally, we explored combinations of eribulin with other drugs commonly used in the treatment of STS with the aim of increasing its antitumour activity.ResultsEribulin showed activity inhibiting proliferation, 2D and 3D migration and invasion in most of the cell line models. Furthermore, we provide data that suggest, for the first time, a synergistic effect with ifosfamide in all models, and with pazopanib in LMS as well as in myxoid and pleomorphic LPS.ConclusionsOur results support the effect of eribulin on LPS, LMS and FS cell line models. The combination of eribulin with ifosfamide or pazopanib has shown in vitro synergy, which warrants further clinical research.

Eribulin Efficacy on Brain Metastases in Heavily Pretreated Patients with Metastatic Breast Cancer.

The onset of brain metastases (BM) is a major turning point during advanced breast cancer (ABC) evolution, with only few treatment options when local therapies have failed. The therapeutic effect of eribulin, a wildly used drug in the treatment of ABC, remains unclear in this setting. Patients and Methods: We performed a retrospective observational study to assess eribulin efficacy in patients with ABC who displayed BM at time of eribulin initiation. We collected data from the medical files of all ABC patients who received eribulin at our institution from 2012 until 2020. Our main endpoint was the central nervous system (CNS) progression-free survival. (CNS-PFS). Other evaluation criteria were extra-cranial progression free survival (PFS) and overall survival (OS). Results: Twenty patients with BM monitoring data available were selected out of the 549 who received eribulin during the inclusion period. Fifteen patients (75%) had BM progressive as the best response, three patients (15%) had disease stabilization for more than 6 months and only one patient had a partial response according to RECIST 1.1 criteria. Median CNS-PFS was 3.39 months (95CI (3.02–3.76)). Cox univariate analysis identified molecular subtype as the only prognostic parameter in our cohort, with patients with hormone-receptor positive tumors less likely to experience CNS progression than those with triple-negative MBC (HR = 0.23 (95CI = 0.07–0.80), p = 0.021). Median extra-cranial PFS was 2.67 months (95CI (2.33–3.01)). Median OS was 7.68 months (95CI (0–17.41)). Conclusion: Eribulin seems to have only a limited impact on BM evolution. Hormone receptors expression may identify a subset of patients with better BM control.

Abstract PS16-14: Eribulin and paclitaxel differentially affect exosome formation and release from triple negative breast cancer cells

Abstract Extracellular vesicles (EVs) containing proteins, DNA, and RNA facilitate cellular crosstalk within and among tissues and are involved in a variety of physiologic and disease processes. Cancer cells secrete EVs that promote multiple aspects of cancer progression, including epithelial-mesenchymal transition (EMT), angiogenesis, metastasis, and immune suppression. EVs are formed by two different mechanisms, budding from the plasma membrane and through the multivesicular endosome pathway, and these subpopulations of EVs are commonly referred to as microvesicles and exosomes respectively. Notably, exosomes range in size from 50-150 nm, while microvesicles can range from 100-1000 nm. Microtubules are important for the vesicular trafficking involved in exosome formation, cargo loading, and release. Therefore, we hypothesized that microtubule targeting drugs would affect the formation and release of exosomes from triple negative breast cancer (TNBC) cells and alter their cargo. We investigated whether eribulin and paclitaxel differently affect exosome formation and release because they have highly divergent effects on microtubules, in that eribulin causes microtubule loss and paclitaxel increases microtubule density. Exosome formation was evaluated by immunofluorescence of the multivesicular endosome/exosome marker, CD63, in multiple TNBC cell lines. Eribulin and paclitaxel significantly altered the cellular localization of CD63 after 4 h. High-content imaging analysis revealed a significant intracellular accumulation of CD63, suggesting that eribulin and paclitaxel could impair exosome release. Small EVs/exosomes were then isolated from TNBC cells treated for 8 h with concentrations of eribulin and paclitaxel that maximally disrupted CD63 without causing significant mitotic accumulation or cell death. Small EVs/exosomes isolated from cell-conditioned media were characterized by electron microscopy, immunoblotting and nanoparticle tracking analysis (NTA). The results of NTA show that while paclitaxel did not change the number of EVs released after an 8 h treatment, eribulin caused a modest, but consistent decrease in the number of EVs released by MDA-MB-231 cells. Immunoblot analysis further revealed a significant reduction in CD63 content of EVs from eribulin, but not paclitaxel-treated MDA-MB-231 cells. Additional fluorescent NTA using CD63 antibody labeling showed that CD63+ EVs were substantially reduced by eribulin but unchanged by paclitaxel. Interestingly, the CD63+ EVs that were isolated from eribulin-treated MDA-MB-231 cells were significantly larger than those from control or paclitaxel-treated cells, demonstrating that eribulin inhibits the release of small CD63+ EVs, likely exosomes. Taken with the fact that the total concentration of small EV particles released by eribulin-treated cells was only modestly reduced, our results suggest that eribulin promotes the release of small microvesicles while inhibiting the release of CD63+ exosomes. This shift in the population of EVs released by TNBC cells as a result of eribulin treatment could have implications for other EV cargo that impact cancer progression. Studies to confirm these effects in additional TNBC cell lines and with other microtubule targeting drugs, as well as proteomic analysis of EV content are ongoing. Furthering our understanding of the differential effects of eribulin and paclitaxel on EV formation and cargo has the potential to inform on the more targeted use of these drugs in the future. These studies were funded by Eisai Inc. Citation Format: Petra EJ Pederson, Huiyun Liang, Susan L Mooberry. Eribulin and paclitaxel differentially affect exosome formation and release from triple negative breast cancer cells [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS16-14.

Dose-response effect of eribulin in preclinical models of osteosarcoma by the pediatric preclinical testing consortium.

The pediatric preclinical testing program previously demonstrated activity of eribulin in osteosarcoma patient-derived xenograft (PDX) models. The phase 2 trial in patients with relapsed osteosarcoma failed to meet response endpoints. Eribulin was evaluated in the original and an expanded set of PDX models and tested at multiple dose levels and schedules to evaluate dose-response. Maximal response was observed at the highest dose, consistent with prior results. The alternative schedule generated similar responses. We demonstrate steep dose-response for eribulin in osteosarcoma PDX models, implying that any deviation from achievement of effective concentrations may have a significant impact on activity.

Abstract P2-15-08: Efficacy and possible predictive factors of eribulin in a real-world population of HER-2 negative metastatic breast cancer patients in Japan

Abstract Background Eribulin mesylate, a non-taxane microtubule inhibitor, has unique characteristics that modify the tumor microenvironment by reversing epithelial-mesenchymal transition (EMT) to mesenchymal-epithelial transition (MET). These effects might benefit the efficacy of chemotherapies, particularly those administered after eribulin. In fact, the EMBRACE study demonstrated that eribulin did not prolong progression-free survival (PFS) but rather overall survival (OS) when compared to the treatment of physician’s choice (TPC). However, the effects of eribulin on post-eribulin chemotherapy regimens remain unclear. Thus, this retrospective study aimed to assess PFS, OS, and post progression survival (PPS) of women with HER-2 negative metastatic breast cancer (MBC) as real-world data. In addition, clinical and pathological factors were analyzed as predictive factors for the survival measurements. Furthermore, the effect of eribulin on post-eribulin chemotherapies was also evaluated by assessing PFS of post-eribulin chemotherapy compared with PFS of eribulin and PFS of pre-eribulin chemotherapy. Methods A total of 75 women with HER-2 negative MBC who were treated with eribulin between January 2011 and June 2019 were included in this study. PFS, OS, and PPS were calculated according to the Kaplan-Meier method for each patient. The clinical and pathological factors analyzed in this study were hormone receptors, age, number of prior regimens, metastatic site, number of metastatic sites, and hematologic parameters such as neutrophil (NEU) counts, lymphocyte (LYM) counts, and neutrophil to lymphocyte ratio (NLR). A cox model was used to correlate these factors with survivals. In this study, PFS of the post-eribulin chemotherapy cohort divided by PFS of the eribulin-receiving cohort or PFS of the pre-eribulin chemotherapy cohort was analyzed as a unique parameter of the PFS ratio (PFSr, the former was PFSr A and the latter was PFSr B). A PFS ratio of 1.0 or higher may be the significantly favorable effect of eribulin on post-eribulin chemotherapy. Of a total of 75 patients, 46 and 36 were analyzed for assessing PFSr A and B, respectively, since patients who were not eligible for the calculation of PFSr were excluded. Single and multiple regression analyses were used to evaluate the associated factors with PFSr B. Results The median PFS, OS, and PPS were 3.5 months (95%CI 2.5-4.4), 13.1 (95% CI 9.4-16.7), and 13.1(95%CI 9.4-22.9), respectively. In univariate analysis, an age of 65 or older (p=0.001) and lower NLR (p=0.003) were associated with longer PFS. In multivariate analyses, an age of 65 or older (p=0.041) and lower NLR (p=0.008) were associated with superior PFS. NEU counts lower than 4500 (p=0.0028) and lower NLR (p=0.003) were correlated with longer OS in both univariate and multivariable analyses. There were no correlating factors with PPS. The median PFSr A and B were 0.86 and 0.65, respectively, and the percentages of PFSr A and B were 43% and 33%, respectively. Single and multiple regression analysis each showed that none of the factors are correlated with PFSr B. Conclusion The median PFS and OS in our study were comparable to those reported in the EMBRACE study which were 3.7 and 13.1 months, respectively. Age and NLR were associated with PFS and NEU count and NLR was associated with OS. The correlation of NEU count and NLR with PFS and OS suggests that the effects of eribulin might be diminished by a high inflammatory state but enhanced by higher oncologic immune status. In terms of eribulin’s effect on post-eribulin chemotherapy, no conclusive data were obtained in this study, and a larger number of patients should be analyzed. Citation Format: Sera Satoi, Hiroyuki Takei, Keiko Yanagihara, Tomoko Kurita, Maki Nakai, Meishi Hankyo, Rina Kanamaru, Ai Sato. Efficacy and possible predictive factors of eribulin in a real-world population of HER-2 negative metastatic breast cancer patients in Japan [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-15-08.

Abstract P3-10-16: Identification of molecules that enhance the efficacy of eribulin in TNBC and IBC cell lines

Abstract BACKGROUND: Eribulin mesylate, a non-taxane microtubule-dynamics inhibitor, is an effective chemotherapy drug for patients with metastatic breast cancer who have previously received at least two chemotherapeutic regimens. We are seeking to enhance the anti-tumor activity of eribulin in metastatic breast cancer cell lines. The purpose of this study was to identify kinase targets that markedly enhance the efficacy of eribulin using high-throughput nonbiased synthetic lethal RNA interference (RNAi) screening and to validate these targets in combination with eribulin using triple-negative breast cancer (TNBC) and inflammatory breast cancer (IBC) cell lines which are heterogeneous diseases and characterized by their high metastatic potential and poor prognosis. METHODS: High-throughput RNAi screening (709-human-kinome library) was performed to identify target kinases. The Bliss scoring method was used to identify potential targets from the screening (using a Bliss score cut-off of 0.15), and protein-protein interactome analysis (STRING V.11) and Ingenuity Pathway Analysis (IPA) were used to identify therapeutic target pathways. To validate the in vitro efficacy of selected targets, we performed CellTiter-Blue or sulforhodamine B cell proliferation and anchorage-independent colony-formation assays in 18 TNBC and 6 IBC cell lines treated with eribulin with or without inhibitors of the discovered targets. RESULTS: In vitro proliferation data demonstrated that single-agent eribulin had a nanomolar range of half-maximal inhibitory concentrations (0.2 - 4.0 nM) in most of the tested cell lines. RNAi screening identified 130 relevant kinase targets. IPA and STRING analysis revealed PI3K/AKT/mTOR, MAPK, JNK, and PAK1 as major canonical pathways that could be targeted to enhance the cytotoxic effect of eribulin. In in vitro cell line validation, PAK1 inhibitor NVS-PAK1-1 and mTOR inhibitor everolimus showed strong combinational anti-tumor effect (combination index values = 0.1 - 0.9), and JNK inhibitor JNK-In-8 showed moderate combinational anti-tumor effect (combination index values = 0.5 - 0.9) in combination with eribulin. Inhibitors of PI3K (copanlisib) and MEK (trametinib) showed combinational anti-tumor effect in some cell lines. CONCLUSION: We identified that PAK1, mTOR, and JNK inhibitors enhanced the anti-proliferation effects of eribulin in TNBC and IBC cell lines. Our data inform new treatment strategies with eribulin for TNBC and IBC that could lead to clinical trials of innovative combination therapy based on eribulin. Citation Format: Jangsoon Lee, Jon A Fuson, Huey Liu, Troy Pearson, Debu Tripathy, Bora Lim, Naoto T Ueno. Identification of molecules that enhance the efficacy of eribulin in TNBC and IBC cell lines [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-10-16.

Abstract P6-07-02: Evaluating the effects of eribulin and paclitaxel on exosome formation and release from triple negative breast cancer cells

Abstract Extracellular vesicles (EVs) are small membrane-bound vesicles released from cells that constitute an important mode of intercellular communication. These vesicles contain bioactive molecules, including proteins, DNA, microRNAs, and lipids that facilitate cellular cross-talk within and among tissues, and they are involved in a variety of physiologic and disease processes. Cancer cells secrete EVs that promote multiple aspects of cancer progression, including epithelial-mesenchymal transition (EMT), angiogenesis, metastasis, and immune suppression. EVs are formed by multiple mechanisms, including budding from the plasma membrane and through the multivesicular endosome pathway, and the latter are commonly referred to as exosomes. Microtubules are important for the vesicular trafficking involved in exosome formation, cargo loading, and release. Therefore, we hypothesized that microtubule targeting drugs would affect the formation and release of exosomes. We investigated whether the microtubule targeting drugs, eribulin and paclitaxel, differently affect exosome formation and release because they have highly divergent effects in cells, in that eribulin causes loss of microtubules and paclitaxel increases microtubule density. Furthermore, eribulin, but not paclitaxel, has been shown to reverse EMT1 and decrease TGF-β in breast cancer patients’ serum.2 TGF-β is a known exosome-associated protein capable of promoting EMT, and therefore, we hypothesize that altered exosome production could contribute to these clinical observations. The effects of eribulin and paclitaxel on the localization of multivesicular endosomes in HCC1937 triple negative breast cancer (TNBC) cells was evaluated by immunofluorescence and cellular CD63 quantified using high content imaging. The results show that a 4-hour treatment of TNBC cells with eribulin caused a rapid and a statistically significant accumulation of the exosome and multivesicular endosome associated protein CD63. Interestingly, paclitaxel had a different effect on CD63 localization in that in some cells there was an accumulation of CD63 in the cell periphery, but in the population, there was no significant difference in CD63 intensity. These results show that eribulin rapidly alters the localization of multivesicular endosomes, which could indicate impaired exosome release. Exosome-enriched extracellular vesicles were isolated from TNBC cells treated with eribulin and paclitaxel for 8 hours at concentrations which maximally disrupt CD63 without significant mitotic accumulation or cell death. Electron microscopy and immunoblot analyses confirmed the isolation of exosome-enriched extracellular vesicles. Nanoparticle tracking analysis is being used to evaluate the number and size of the exosomes to test whether eribulin and paclitaxel affect their release. Future studies will involve proteomic analysis of exosomes from cells treated with eribulin and paclitaxel to determine whether the drugs differentially affect exosome cargo, such as TGF-β. Understanding the effects of diverse MTAs on exosomes and their cargo has the potential to inform a more targeted use of these drugs in the clinic. These studies were funded by Eisai Inc. 1. Yoshida, T. et al. Eribulin mesilate suppresses experimental metastasis of breast cancer cells by reversing phenotype from epithelial–mesenchymal transition (EMT) to mesenchymal–epithelial transition (MET) states. Br. J. Cancer 110, (2014). 2. Ueda, S. et al. In vivo imaging of eribulin-induced reoxygenation in advanced breast cancer patients: a comparison to bevacizumab. Br. J. Cancer 114, 1212–8 (2016). Citation Format: Petra Elizabeth Jans Pederson, Susan L Mooberry. Evaluating the effects of eribulin and paclitaxel on exosome formation and release from triple negative breast cancer cells [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-07-02.

Abstract P1-10-30: Survival benefit of eribulin for metastatic breast cancer depends on absolute lymphocyte count and neutrophil-lymphocyte ratio in peripheral blood

Abstract Background and Aims: Eribulin is a cytotoxic anti-cancer agent targeting microtubule dynamics, which improves the prognosis of patients with metastatic breast cancer. Preclinical studies have shown that eribulin enhances anti-tumor immunity by inhibiting regulatory T cells and M2 macrophages. Along with advances of immunotherapy for breast cancer, there has been growing interest in such immunologic effects of eribulin. Here we investigated the association between the immunological status of peripheral blood and survival outcomes in patients receiving eribulin for metastatic breast cancer. Methods: Medical records of 125 patients who received eribulin for metastatic breast cancer at Hiroshima City Hiroshima Citizens Hospital between July 2011 and April 2019 were retrospectively reviewed. We collected the data on patients’ baseline characteristics, laboratory tests and clinical courses. Absolute lymphocyte count (ALC) and neutrophil-lymphocyte ratio (NLR) in peripheral blood at the start of treatment with eribulin were calculated, and their association with progression-free survival (PFS) and overall survival (OS) were analyzed with log-rank test. The cutoff values for ALC and NLR were determined based on their distribution in this cohort. Subgroup analyses by breast cancer subtypes were also conducted. Results: The mean age was 57 years (range, 28-88). Eighty (64%) and 14 (11.2%) patients were positive for hormone receptors and HER2 overexpression. One hundred and ten patients (88%) had received one or more lines of chemotherapy for metastatic disease. We divided the entire cohort into three groups, using the cutoff values of 1500 /µL for ALC and 5 for NLR. Accordingly, 30 patients (24%) had favorable immune status (i.e., ALC ≥1500 /µL), whereas immune systems were considered to be suppressed (i.e., NLR ≥5) in 19 patients (15.2%); the rest 76 patients (60.8%) had neutral immune status (i.e., ALC <1500 /µL and NLR <5). Overall, ALC ≥1500 /µL was significantly associated with better PFS (hazard ratio, 0.55; 95% CI, 0.35-0.88; p=.013). In contrast, NLR ≥5 were significantly associated with worse PFS (hazard ratio, 1.92; 95% CI, 1.11-3.32; p=.019) and OS (hazard ratio, 4.26; 95% CI, 2.29-7.91; p<.001). These trends in relationship between ALC/NLR and survival outcomes were consistent across subgroups. Conclusions: The potential role of immune status of peripheral blood, such as ALC ≥1500 /µL and NLR ≥5, in predicting the efficacy of eribulin for metastatic breast cancer was suggested. Selecting patients with favorable immune status will be important to make the best use of eribulin. Citation Format: Ayako Ueno, Shoichiro Ohtani, Kensuke Kawasaki, Mitsuya Ito, Takanori Kin, Reina Maeda. Survival benefit of eribulin for metastatic breast cancer depends on absolute lymphocyte count and neutrophil-lymphocyte ratio in peripheral blood [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-10-30.