Eribulin -- a review of preclinical and clinical studies

Natural-source payloads used in the conjugated drugs architecture for cancer therapy: Recent advances and future directions

Drug conjugates are obtained from tumor-located vectors connected to cytotoxic agents via linkers, which are designed to deliver hyper-toxic payloads directly to targeted cancer cells. These drug conjugates include antibody-drug conjugates (ADCs), peptide-drug conjugates (PDCs), small molecule-drug conjugates (SMDCs), nucleic acid aptamer-drug conjugates (ApDCs), and virus-like drug conjugate (VDCs), which show great therapeutic value in the clinic. Drug conjugates consist of a targeting carrier, a linker, and a payload. Payloads are key therapy components. Cytotoxic molecules and their derivatives derived from natural products are commonly used in the payload portion of conjugates. The ideal payload should have sufficient toxicity, stability, coupling sites, and the ability to be released under specific conditions to kill tumor cells. Microtubule protein inhibitors, DNA damage agents, and RNA inhibitors are common cytotoxic molecules. Among these conjugates, cytotoxic molecules of natural origin are summarized based on their mechanism of action, conformational relationships, and the discovery of new derivatives. This paper also mentions some cytotoxic molecules that have the potential to be payloads. It also summarizes the latest technologies and novel conjugates developed in recent years to overcome the shortcomings of ADCs, PDCs, SMDCs, ApDCs, and VDCs. In addition, this paper summarizes the clinical trials conducted on conjugates of these cytotoxic molecules over the last five years. It provides a reference for designing and developing safer and more efficient conjugates.

Genomic and transcriptomic profiles associated with response to eribulin and nivolumab combination in HER-2-negative metastatic breast cancer

BACKGROUND

Biomarkers for predicting response to the immunotherapy and chemotherapy combination in breast cancer patients are not established. In this study, we report exploratory genomic and transcriptomic analyses of pretreatment tumor tissues from patients enrolled in phase II clinical trial of a combination of eribulin and nivolumab for HER-2-negative metastatic breast cancer (MBC) (KORNELIA trial, NCT04061863).

METHODS

We analyzed associations between tumor molecular profiles based on genomic (n = 76) and transcriptomic data (n = 58) and therapeutic efficacy. Patients who achieved progression-free survival (PFS) ≥ 6 months were defined as PFS6-responders and PFS6-nonresponders otherwise.

FINDINGS

Analyses on tumor mutation burden (TMB) showed a tendency toward a favorable effect on efficacy, while several analyses related to homologous recombination deficiency (HRD) indicated a potentially negative impact on efficacy. Patients harboring TP53 mutations showed significantly poor PFS6 rate and PFS, which correlated with the enrichment of cell cycle-related signatures in PFS6-nonresponders. High antigen presentation gene set enrichment scores (≥ median) were significantly associated with longer PFS. Naïve B-cell and plasma cell proportions were considerably higher in long responders (≥ 18 months).

INTERPRETATION

Genomic features including TMB, HRD, and TP53 mutations and transcriptomic features related to immune cell profiles and cell cycle may distinguish responders. Our findings provide insights for further exploring the combination regimen and its biomarkers in these tumors.

Eribulin in breast cancer: Current insights and therapeutic perspectives

Eribulin is a non-taxane synthetic analogue approved in many countries as third-line treatment for the treatment of patients with metastatic breast cancer. In addition to its mitotic property, eribulin has non-mitotic properties including but not limited to, its ability to induce phenotypic reversal of epithelial to mesenchymal transition, vascular remodelling, reduction in immunosuppressive tumour microenvironment. Since approval, there has been a surge in studies investigating the application of eribulin as an earlier-line treatment and also in combination with other agents such as immunotherapy and targeted therapy across all breast cancer sub-types, including hormone receptor positive, HER2 positive and triple negative breast cancer, many demonstrating promising activity. This review will focus on the application of eribulin in the treatment of metastatic breast cancer across all subtypes including its role as an earlier-line agent, its toxicity profile, and potential future directions.

Evaluation of Copanlisib in Combination with Eribulin in Triple-negative Breast Cancer Patient-derived Xenograft Models

The PI3K pathway regulates essential cellular functions and promotes chemotherapy resistance. Activation of PI3K pathway signaling is commonly observed in triple-negative breast cancer (TNBC). However previous studies that combined PI3K pathway inhibitors with taxane regimens have yielded inconsistent results. We therefore set out to examine whether the combination of copanlisib, a clinical grade pan-PI3K inhibitor, and eribulin, an antimitotic chemotherapy approved for taxane-resistant metastatic breast cancer, improves the antitumor effect in TNBC. A panel of eight TNBC patient-derived xenograft (PDX) models was tested for tumor growth response to copanlisib and eribulin, alone or in combination. Treatment-induced signaling changes were examined by reverse phase protein array, immunohistochemistry (IHC) and 18F-fluorodeoxyglucose PET (18F-FDG PET). Compared with each drug alone, the combination of eribulin and copanlisib led to enhanced tumor growth inhibition, which was observed in both eribulin-sensitive and -resistant TNBC PDX models, regardless of PI3K pathway alterations or PTEN status. Copanlisib reduced PI3K signaling and enhanced eribulin-induced mitotic arrest. The combination enhanced induction of apoptosis compared with each drug alone. Interestingly, eribulin upregulated PI3K pathway signaling in PDX tumors, as demonstrated by increased tracer uptake by 18F-FDG PET scan and AKT phosphorylation by IHC. These changes were inhibited by the addition of copanlisib. These data support further clinical development for the combination of copanlisib and eribulin and led to a phase I/II trial of copanlisib and eribulin in patients with metastatic TNBC.

SIGNIFICANCE

In this research, we demonstrated that the pan-PI3K inhibitor copanlisib enhanced the cytotoxicity of eribulin in a panel of TNBC PDX models. The improved tumor growth inhibition was irrespective of PI3K pathway alteration and was corroborated by the enhanced mitotic arrest and apoptotic induction observed in PDX tumors after combination therapy compared with each drug alone. These data provide the preclinical rationale for the clinical testing in TNBC.

An update on the development on tubulin inhibitors for the treatment of solid tumors

INTRODUCTION

Microtubules play a vital role in cancer therapeutics. They are implicated in tumorigenesis, thus inhibiting tubulin polymerization in cancer cells, and have now become a significant target for anticancer drug development. A plethora of drug molecules has been crafted to influence microtubule dynamics and presently, numerous tubulin inhibitors are being investigated. This review discusses the recently developed inhibitors including natural products, and also examines the preclinical and clinical data of some potential molecules.

AREA COVERED

The current review article summarizes the development of tubulin inhibitors while detailing their specific binding sites. It also discusses the newly designed inhibitors that may be useful in the treatment of solid tumors.

EXPERT OPINION

Microtubules play a crucial role in cellular processes, especially in cancer therapy where inhibiting tubulin polymerization holds promise. Ongoing trials signify a commitment to revolutionizing cancer treatment and exploring targeted therapies. Challenges in microtubule modulation, like resistance and off-target effects, demand focused efforts, emphasizing combination therapies and personalized treatments. Beyond microtubules, promising avenues in cancer research include immunotherapy, genomic medicine, CRISPR gene editing, liquid biopsies, AI diagnostics, and stem cell therapy, showcasing a holistic approach for future advancements.

Tubulin inhibitors. Selected scaffolds and main trends in the design of novel anticancer and antiparasitic agents

Design of tubulin inhibitors as anticancer drugs dynamically developed over the past 20 years. The modern arsenal of potential tubulin-targeting anticancer agents is represented by small molecules, monoclonal antibodies, and antibody-drug conjugates. Moreover, targeting tubulin has been a successful strategy in the development of antiparasitic drugs. In the present review, an overall picture of the research and development of potential tubulin-targeting agents using small molecules between 2018 and 2023 is provided. The data about some most often used and prospective chemotypes of small molecules (privileged heterocycles, moieties of natural molecules) and synthetic methodologies (analogue-based, fragment-based drug design, molecular hybridization) applied for the design of novel agents with an impact on the tubulin system are summarized. The design and prospects of multi-target agents with an impact on the tubulin system were also highlighted. Reported in the review data contribute to the "structure-activity" profile of tubulin-targeting small molecules as anticancer and antiparasitic agents and will be useful for the application by medicinal chemists in further exploration, design, improvement, and optimization of this class of molecules.

Cucurbitacin E Exerts Anti-Proliferative Activity via Promoting p62-Dependent Apoptosis in Human Non-Small-Cell Lung Cancer A549 Cells

EGFR tyrosine kinase inhibitors (TKIs) are the first-line treatment for advanced EGFR-mutated non-small-cell lung cancer (NSCLC). However, NSCLC patients with wild-type EGFR and KRAS mutation are ineligible for EGFR-TKIs. Therefore, the discovery of new therapeutic agents is urgently needed for NSCLC patients who cannot receive targeted therapies. Natural products possess tremendous chemical diversity and have been extensively investigated for their anticancer activity. In this study, we found that Cucurbitacin E (Cu E), a triterpene of cucurbitacins widely presented in the edible plants of the Cucurbitaceae family, significantly inhibits the viability and proliferation of A549 cells that harbor wild-type EGFR and KRAS mutation. Our results revealed that Cu E increases cell-cycle arrest at G2/M and subG1 phase. Mechanistically, Cu E significantly inhibits the phosphorylation and protein levels of regulatory proteins and hinders G2/M cell-cycle progression. Meanwhile, the treatment of Cu E resulted in DNA damage response and apoptosis. For the first time, we observed that Cu E induces incomplete autophagy as evidenced by increased LC3B-II expression and p62-accumulation. Knockdown of p62 rescued the cells from Cu E-mediated anti-proliferative effect, apoptosis, DNA damage, and ROS production. These findings suggest that Cu E is a promising drug candidate for NSCLC.

Eribulin mesylate induces bone mass loss by promoting osteoclastic bone resorption in mice

Over the past few decades, the clinical outcomes of patients with cancer have significantly improved mostly owing to the development of effective chemotherapeutic treatments. However, chronic health conditions such as bone mass loss and risk of fragility fractures caused by chemotherapy have also emerged as crucial issues in patients treated for cancer. In this study, we aimed to understand the effect of eribulin mesylate (ERI), a microtubule-targeting agent currently used to treat metastatic breast cancer and certain subtypes of advanced sarcomas, on bone metabolism in mice. The administration of ERI reduced bone mass in mice, mainly by promoting osteoclast activity. Gene expression analysis of skeletal tissues revealed no change in the expression levels of the transcripts for RANK ligand, one of the master regulators of osteoclastogenesis; however, the transcript levels of osteoprotegerin, which neutralizes RANK ligand, were significantly reduced in ERI-treated mice compared with those in vehicle-treated controls, indicating a relative increase in RANK ligand availability after ERI treatment. In line with the increased bone resorption in ERI-treated mice, we found that zoledronate administration effectively suppressed bone loss in these mice. These results reveal a previously unrecognized effect of ERI on bone metabolism and suggest the application of bisphosphonates for patients with cancer undergoing treatment with ERI.

Eribulin inhibits growth of cutaneous squamous cell carcinoma cell lines and a novel patient-derived xenograft

Advanced cutaneous squamous cell carcinoma (cSCC) is treated with chemotherapy and/or radiotherapy, but these typically fail to achieve satisfactory clinical outcomes. There have been no preclinical studies to evaluate the effectiveness of eribulin against cSCC. Here, we examine the effects of eribulin using cSCC cell lines and a novel cSCC patient-derived xenograft (PDX) model. In the cSCC cell lines (A431 and DJM-1 cells), eribulin was found to inhibit tumor cell proliferation in vitro as assessed by cell ATP levels. DNA content analysis by fluorescence-activated cell sorting (FACS) showed that eribulin induced G2/M cell cycle arrest and apoptosis. In xenograft models of cSCC cell lines, the administration of eribulin suppressed tumor growth in vivo. We also developed a cSCC patient-derived xenograft (PDX) which reproduces the histological and genetic characteristics of a primary tumor. Pathogenic mutations in TP53 and ARID2 were detected in the patient's metastatic tumor and in the PDX tumor. The cSCC-PDX responded well to the administration of eribulin and cisplatin. In conclusion, the present study shows the promising antineoplastic effects of eribulin in cSCC. Also, we established a novel cSCC-PDX model that preserves the patient's tumor. This PDX could assist researchers who are exploring innovative therapies for cSCC.

Eribulin as first-line treatment in older patients with advanced breast cancer: A multicenter phase II trial [SAKK 25/14]

INTRODUCTION

Standard-dose eribulin mesylate (1.4 mg/m² d1 + 8) achieves clinical benefit rates of 26%-52% in patients with metastatic breast cancer (mBC). <10% of patients in the registration trial were ≥ 70 years old; dose reductions were common in these older patients.

MATERIALS AND METHODS

This single-arm phase II trial explored the efficacy of reduced starting dosing of first-line eribulin at 1 mg/m² d1 + 8 q3 weeks in patients with mBC aged ≥70 years. The primary endpoint was a disease control rate (DCR) ≥55%. The secondary endpoints were objective response (OR), progression-free survival (PFS), overall survival (OS), and patient-reported neurotoxicity.

RESULTS

Overall, 77 patients were accrued; their median age was 76 years and Eastern Cooperative Oncology Group performance status was 0-1 in 90%. The DCR was 40% (90% confidence interval [CI]: 31-50); therefore, the primary endpoint was not reached. The overall response rate was 22% (95%CI: 13-33), median PFS 5.4 months (95%CI: 4.5-7.7), and median OS 16.1 months (95%CI: 13.5-26.9). Dose modifications were necessary in 35% of patients. In nine patients, more than fifteen cycles were given; 48 patients (62%) experienced at least one grade 3 toxicity. Median patient-reported neurotoxicity scores remained stable for at least fifteen cycles. The main reason for treatment discontinuation was disease progression (57%).

DISCUSSION

We report the first prospective data on first-line eribulin in older patients. The reduced starting dose of 1.1 mg/m² was safe, with prolonged treatment and DC achieved in a considerable proportion of patients (but less than the 55% assumed), without cumulative neurotoxicity. The reduced dose was apparently within the range of the minimal effective dose, as shown by the efficacy lack in patients requiring further dose reductions. Thus, our results do not support the approach of a reduced starting dose for older patients.

New Drug Approvals for Sarcoma in the Last 5 Years

Sarcoma and locally aggressive connective tissue tumors are a complex group of diseases with a growing number of histotypes in the most recent WHO classification. Most of these tumors are rare (incidence <6/10⁵/y) or ultrarare (<1/10⁶/y). Despite their rarity, sarcomas are often good models for the development of personalized medicine, and a large number of new clinical trials in select histotypes and molecular subsets were reported during the past 5 years, leading to a faster rate of new drug approvals. We analyzed the published literature and the abstracts reported in major congresses dedicated to sarcoma and connective tissue tumor management in the last 5 years. Several targeted therapies, cytotoxic treatments, and immunotherapies have demonstrated activity in dedicated histologic and molecular subtypes of sarcomas. The majority of the studies for ultrarare entities are uncontrolled studies, as a consequence of the rarity of histotypes, but randomized controlled trials were available in the less rare histotypes. Most successful trials were based on biomarker selection, which were often driver molecular alterations, while a large number of ongoing research programs aim to identify biomarkers in parallel to new drug development. Availability of the new agents varies across countries. This article describes the new drugs that made it through to the finish line and new agents with promising activity that are in later stages of investigation in the large family of malignant connective tissue tumors.

Oncological Treatment-Related Fatigue in Oncogeriatrics: A Scoping Review

Fatigue is a highly prevalent symptom in both cancer patients and the older population, and it contributes to quality-of-life impairment. Cancer treatment-related fatigue should thus be included in the risk/benefit assessment when introducing any treatment, but tools are lacking to a priori estimate such risk. This scoping review was designed to report the current evidence regarding the frequency of fatigue for the different treatment regimens proposed for the main cancer indications, with a specific focus on age-specific data, for the following tumors: breast, ovary, prostate, urothelium, colon, lung and lymphoma. Fatigue was most frequently reported using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) versions 3 to 5. A total of 324 regimens were analyzed; data on fatigue were available for 217 (67%) of them, and data specific to older patients were available for 35 (11%) of them; recent pivotal trials have generally reported more fatigue grades than older studies, illustrating increasing concern over time. This scoping review presents an easy-to-understand summary that is expected to provide helpful information for shared decisions with patients regarding the anticipation and prevention of fatigue during each cancer treatment.

Optimization of G-CSF dosing schedule in patients treated with eribulin: a modeling approach

BACKGROUND

Granulocyte colony-stimulating factors (G-CSF) are commonly given to limit chemotherapy-induced neutropenia, but, in case of weekly chemotherapy such as eribulin, their administration schedules remain empirical.

OBJECTIVES

This pharmacokinetic/pharmacodynamic (PK/PD) study was conducted to establish the effect of different G-CSF regimens on neutropenia's incidence for patients treated by eribulin, to propose an optimal G-CSF dosing schedule.

METHODS

A population PK/PD model was developed to describe absolute neutrophil counts' (ANC) time course in 87 cancer patients receiving eribulin. The structural model considered ANC dynamics, neutropenic effect of eribulin and stimulating effect of G-CSF. Final model estimates were used to calculate neutropenia's incidence following different G-CSF dosing schedules for 1000 virtual subjects.

RESULTS

The final model successfully described most of the ANC time course for all patients. Simulations showed that a single G-CSF administration 48 h after each eribulin injection reduced the risk of severe neutropenia from 29.7 to 5.2%. Five days of G-CSF only after the second eribulin injection or no G-CSF administration induces similar incidence of neutropenia.

CONCLUSION

Simulations showed a single G-CSF administration 48 h after the end of each eribulin injection seems to be the optimal schedule to reduce eribulin-induced neutropenia. However, the new administration scheme should be tested in real life to evaluate its pertinence.

TRIAL REGISTRATION

Eudract 2015-001753-32, 2015/01/26.

Combination of Abemaciclib following Eribulin Overcomes Palbociclib-Resistant Breast Cancer by Inhibiting the G2/M Cell Cycle Phase

Breast cancer remains a leading cancer burden among women worldwide. Acquired resistance of cyclin-dependent kinase (CDK) 4/6 inhibitors occurs in almost all hormone receptor (HR)-positive subtype cases, comprising 70% of breast cancers, although CDK4/6 inhibitors combined with endocrine therapy are highly effective. CDK4/6 inhibitors are not expected to cooperate with cytotoxic chemotherapy based on the basic cytotoxic chemotherapy mode of action that inhibits rapidly proliferating cells. The palbociclib-resistant preclinical model developed in the current study investigated whether the combination of abemaciclib, CDK4/6 inhibitor with eribulin, an antimitotic chemotherapy could be a strategy to overcome palbociclib-resistant HR-positive breast cancer. The current study demonstrated that sequential abemaciclib treatment following eribulin synergistically suppressed CDK4/6 inhibitor-resistant cells by inhibiting the G2/M cell cycle phase more effectively. The current study showed the significant association of the pole-like kinase 1 (PLK1) level and palbociclib resistance. Moreover, the cumulative PLK1 inhibition in the G2/M phase by each eribulin or abemaciclib proved to be a mechanism of the synergistic effect. The synergistic antitumor effect was also supported by in vivo study. The sequential combination of abemaciclib following eribulin merits further clinical trials to overcome resistance to CDK4/6 inhibitors in HR-positive breast cancer.

Eribulin induces tumor vascular remodeling through intussusceptive angiogenesis in a sarcoma xenograft model

Eribulin is a novel microtubule inhibitor that, similar to other types of microtubule inhibitors, induces apoptosis by inhibiting the mitotic division of cells. Besides this direct effect on tumor cells, previous studies have shown that eribulin has the potential to induce tumor vascular remodeling in several different cancers; however, the mechanisms underlying this phenomenon remain unclear. In the present study, we aimed to elucidate whether eribulin is effective against synovial sarcoma, a relatively rare sarcoma that often affects adolescents and young adults, and to histologically investigate the microstructure of tumor vessels after the administration of eribulin. We found that eribulin exhibits potent antitumor activity against synovial sarcoma in a tumor xenograft model and that tumor vessels frequently have intervascular pillars, a hallmark of intussusceptive angiogenesis (IA), after the administration of eribulin. IA is a distinct form of angiogenesis that is involved in normal developmental processes as well as pathological conditions. Our data indicate that IA is potentially involved in eribulin-induced vascular remodeling and thereby suggest previously unacknowledged role of IA in regulating the tumor vasculature after eribulin administration.

In vitro Evaluation of Isatin derivatives as Potent Anti-Breast Cancer Agents against MCF-7, MDA MB 231, MDA-MB 435 and MDA-MB 468 Breast Cancers cell lines: A Review

INTRODUCTION

Breast cancer (BC) is one of the most frequent malignancy and most common reasons of impermanence in women. The backbone of therapy for BC is principally chemotherapy, but due to its non-specific nature between normal cells and cancer cells and severe side effects are the main barriers in its therapy. So, there is an intense requirement for the enlargement of more efficacious, more specific and safer anti-BC agents.

OBJECTIVE

Isatin (IST) is an endogenous molecule which is a principal class of heterocyclic compounds and exhibits a wide range of therapeutic activities which can be used as a starting material for the synthesis of several drug molecules. Many literatures were reported previously on different pharmacological activities of IST derivatives and particularly on anticancer activity but this review mainly focus on anti-BC activities of IST derivatives through MCF-7, MDA MB 231, MDA-MB 435 and MDA-MB 468 cell lines. Here in we mentioned, a total 33 IST derivatives (compound 24- 56) which shown good anti-BC activity. IST derived compounds are also available in market and are used for various cancer types like sunitinib for renal cell carcinoma (RCC) and Nintedanib used for the cryptogenic fibrosing alveolitis treatment but when evaluated for BC did not get much success.

CONCLUSION

This review mainly highlights anti-BC activities of various IST analogues using MCF-7, MDA MB 231, MDA-MB 435 and MDA-MB 468 cell lines, display the potent compound of the series and structure-activity relationships of compounds with molecular docking also. So, this study mainly shows the importance of IST as major sources for drug design and development of newer anti-BC drugs.

Eribulin improves tumor oxygenation demonstrated by 18F-DiFA hypoxia imaging, leading to radio-sensitization in human cancer xenograft models

PURPOSE

Eribulin, an inhibitor of microtubule dynamics, is known to show antitumor effects through its remodeling activity in the tumor vasculature. However, the extent to which the improvement of tumor hypoxia by eribulin affects radio-sensitivity remains unclear. We utilized 1-(2,2-dihydroxymethyl-3-¹⁸F-fluoropropyl)-2-nitroimidazole (¹⁸F-DiFA), a new PET probe for hypoxia, to investigate the effects of eribulin on tumor hypoxia and evaluate the radio-sensitivity during eribulin treatment.

METHODS

Mice bearing human breast cancer MDA-MB-231 cells or human lung cancer NCI-H1975 cells were administered a single dose of eribulin. After administration, mice were injected with ¹⁸F-DiFA and pimonidazole, and tumor hypoxia regions were analyzed. For the group that received combined treatment with radiation, ¹⁸F-DiFA PET/CT imaging was performed before tumors were locally X-irradiated. Tumor size was measured every other day after irradiation.

RESULTS

Eribulin significantly reduced ¹⁸F-DiFA accumulation levels in a dose-dependent manner. Furthermore, the reduction in ¹⁸F-DiFA accumulation levels by eribulin was most significant 7 days after treatment. These results were also supported by reduction of the pimonidazole-positive hypoxic region. The combined treatment showed significant retardation of tumor growth in comparison with the control, radiation-alone, and drug-alone groups. Importantly, tumor growth after irradiation was inversely correlated with ¹⁸F-DiFA accumulation.

CONCLUSION

These results demonstrated that ¹⁸F-DiFA PET/CT clearly detected eribulin-induced tumor oxygenation and that eribulin efficiently enhanced the antitumor activity of radiation by improving tumor oxygenation.

Malformin-A1 (MA1) Sensitizes Chemoresistant Ovarian Cancer Cells to Cisplatin-Induced Apoptosis

High-grade epithelial ovarian cancer is a fatal disease in women frequently associated with drug resistance and poor outcomes. We previously demonstrated that a marine-derived compound MalforminA1 (MA1) was cytotoxic for the breast cancer cell line MCF-7. In this study, we aimed to examine the effect of MA1 on human ovarian cancer cells. The potential cytotoxicity of MA1was tested on cisplatin-sensitive (A2780S) and cisplatin-resistant (A2780CP) ovarian cancer cell lines using AlamarBlue assay, Hoechst dye, flow cytometry, Western blot, and RT-qPCR. MA1 had higher cytotoxic activity on A2780S (IC50 = 0.23 µM) and A2780CP (IC50 = 0.34 µM) cell lines when compared to cisplatin (IC50 = 31.4 µM and 76.9 µM, respectively). Flow cytometry analysis confirmed the cytotoxic effect of MA1. The synergistic effect of the two drugs was obvious, since only 13% of A2780S and 7% of A2780CP cells remained alive after 24 h of treatment with both MA1 and cisplatin. Moreover, we examined the expression of bcl2, p53, caspase3/9 genes at RNA and protein levels using RT-qPCR and Western blot, respectively, to figure out the cell death mechanism induced by MA1. A significant down-regulation in bcl2 and p53 genes was observed in treated cells compared to non-treated cells (p < 0.05), suggesting that MA1 may not follow the canonical pathway to induce apoptosis in ovarian cancer cell lines. MalforminA1 showed promising anticancer activity by inducing cytotoxicity in cisplatin-sensitive and cisplatin-resistant cancer cell lines. Interestingly, a synergistic effect was observed when MA1 was combined with cisplatin, leading to it overcoming its resistance to cisplatin.

Perspectives and controversies regarding the use of natural products for the treatment of lung cancer

Lung cancer is the leading cause of cancer‐related mortality both in men and women and accounts for 18.4% of all cancer‐related deaths. Although advanced therapy methods have been developed, the prognosis of lung cancer patients remains extremely poor. Over the past few decades, clinicians and researchers have found that chemical compounds extracted from natural products may be useful for treating lung cancer. Drug formulations derived from natural compounds, such as paclitaxel, doxorubicin, and camptothecin, have been successfully used as chemotherapeutics for lung cancer. In recent years, hundreds of new natural compounds that can be used to treat lung cancer have been found through basic and sub‐clinical research. However, there has not been a corresponding increase in the number of drugs that have been used in a clinical setting. The probable reasons may include low solubility, limited absorption, unfavorable metabolism, and severe side effects. In this review, we present a summary of the natural compounds that have been proven to be effective for the treatment of lung cancer, as well as an understanding of the mechanisms underlying their pharmacological effects. We have also highlighted current controversies and have attempted to provide solutions for the clinical translation of these compounds.

Cu-catalyzed hydroxycyclopropanol ring-opening cyclization to tetrahydrofurans and tetrahydropyrans: short total syntheses of hyperiones

Tetrahydrofurans (THFs) and tetrahydropyrans (THPs) are important core scaffolds frequently found in many molecules of medicinal importance. Herein, we report a novel copper-catalyzed hydroxycyclopropanol ring-opening cyclization methodology to synthesize di- or tri-substituted THFs and THPs. In this reaction, a strained C-C bond was cleaved and a new Csp3-O bond was formed to produce the aforementioned O-heterocycles. The new THF synthesis features a broad substrate scope, scalability, and good functional-group tolerability. It enabled us to complete the shortest enantioselective syntheses of hyperiones A and B (3 and 4 steps, respectively), which is significantly shorter than the previously reported two total syntheses (≥10 steps).

Neurotoxicity of antineoplastic drugs: Mechanisms, susceptibility, and neuroprotective strategies

This review summarizes the adverse effects on the central and/or peripheral nervous systems that may occur in response to antineoplastic drugs. In particular, we describe the neurotoxic side effects of the most commonly used drugs, such as platinum compounds, doxorubicin, ifosfamide, 5-fluorouracil, vinca alkaloids, taxanes, methotrexate, bortezomib and thalidomide. Neurotoxicity may result from direct action of compounds on the nervous system or from metabolic alterations produced indirectly by these drugs, and either the central nervous system or the peripheral nervous system, or both, may be affected. The incidence and severity of neurotoxicity are principally related to the dose, to the duration of treatment, and to the dose intensity, though other factors, such as age, concurrent pathologies, and genetic predisposition may enhance the occurrence of side effects. To avoid or reduce the onset and severity of these neurotoxic effects, the use of neuroprotective compounds and/or strategies may be helpful, thereby enhancing the therapeutic effectiveness of antineoplastic drug.

The microtubule targeting agents eribulin and paclitaxel activate similar signaling pathways and induce cell death predominantly in a caspase-independent manner

Microtubule-targeting agents (MTAs) are the most effective chemotherapeutics used in cancer therapy to date, but their clinical use is often hampered by the acquisition of resistance. Thereby, elucidation of the molecular signaling pathways activated by novel FDA-approved MTAs such as eribulin is important for future therapeutic applications. In contrast to several reports, we show here that regardless of the presence of caspase-3, clinically relevant concentrations of eribulin and the classical MTA paclitaxel predominantly induce caspase-independent cell death in MCF-7 breast carcinoma cells. On the molecular level, several key proteins involved in apoptosis such as p53, Plk1, caspase-2, and Bim as well as the two MAPKs ERK and JNK were activated by both compounds to a similar extent. However, none of them proved to be important for eribulin- and paclitaxel-induced cytotoxicity, as their siRNA-mediated knockdown or inactivation by small molecule inhibitors did not alter cell death rates. In contrast, knockdown of the anti-apoptotic Bcl-2 protein, which becomes heavily phosphorylated at Ser70 during MTA treatment, resulted surprisingly in a reduction of MTA-mediated cell death. This phenomenon can be most likely explained by our observation that the absence of Bcl-2 slowed down cell cycle progression resulting in fewer cells entering mitosis, thereby delaying the mitotic capability of these MTAs to induce cell death. Taken together, although eribulin and paclitaxel disturb the mitotic spindle differently, they exhibit no functional differences in downstream molecular cell death signaling in MCF-7 breast cancer cells.

Decreased Disposition of Anticancer Drugs Predominantly Eliminated via the Liver in Patients with Renal Failure

Background:

Evidence has revealed that renal impairment can affect the systemic exposure of drugs which are predominantly eliminated via the liver. The modulation of drug-metabolizing enzymes and transporters expressed in the liver and/or small intestine by diverse entities, including uremic toxins, in systemic circulation of patients with severe renal failure is considered as the cause of atypical pharmacokinetics, which sometimes induce undesirable adverse events that are especially critical for drugs with narrow therapeutic window such as anticancer drugs. A dosing strategy for anticancer drugs in these patients needs to be established.

Methods:

The effects of renal impairment on the systemic exposure and safety of anticancer drugs were summarized. The proposed mechanisms for the alterations in the pharmacokinetics of these anticancer drugs were also discussed.

Results:

Changes in pharmacokinetics and clinical response were reported in 9 out of 10 cytotoxic anticancer drugs investigated, although available information was limited and sometimes controversial. Systemic exposure of 3 out of 16 tyrosine kinase inhibitors was higher in patients with severe renal failure than that in patients with normal kidney function. An increase in systemic exposure of anticancer drugs in patients with renal impairment is likely to be observed for substrates of OATP1B1, despite the limited evidence.

Conclusion:

The molecular basis for the effect of uremia on non-renal drug elimination still needed to be clarified with further studies to generate generalizable concepts, which may provide insights into establishing better clinical usage of anticancer drugs, i.e. identifying patients at risk and dose adjustment.

Vinca alkaloids, thalidomide and eribulin-induced peripheral neurotoxicity: From pathogenesis to treatment

Vinca alkaloids, thalidomide, and eribulin are widely used to treat patients with childhood acute lymphoblastic leukemia (ALL), adults affected by multiple myeloma and locally invasive or metastatic breast cancer, respectively. However, soon after their introduction into clinical practice, chemotherapy-induced peripheral neurotoxicity (CIPN) emerged as their main non-hematological and among dose-limiting adverse events. It is generally perceived that vinca alkaloids and the antiangiogenic agent thalidomide are more neurotoxic, compared to eribulin. The exposure to these chemotherapeutic agents is associated with an axonal, length-dependent, sensory polyneuropathy of mild to moderate severity, whereas it is considered that the peripheral nerve damage, unless severe, usually resolves soon after treatment discontinuation. Advanced age, high initial and prolonged dosing, coadministration of other neurotoxic chemotherapeutic agents and pre-existing neuropathy are the common risk factors. Pharmacogenetic biomarkers might be used to define patients at increased susceptibility of CIPN. Currently, there is no established therapy for CIPN prevention or treatment; symptomatic treatment for neuropathic pain and dose reduction or withdrawal in severe cases is considered, at the cost of reduced cancer therapeutic efficacy. This review critically examines the pathogenesis, epidemiology, risk factors (both clinical and pharmacogenetic), clinical phenotype and management of CIPN as a result of exposure to vinca alkaloids, thalidomide and its analogue lenalidomide as also eribulin.

Selectively high efficacy of eribulin against high-grade invasive recurrent and/or metastatic squamous cell carcinoma of the head and neck

Patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN) have a poor prognosis. Over the past decade, a major development in the first-line treatment of R/M SCCHN was the introduction of cetuximab in combination with platinum plus 5-fluorouracil chemotherapy. Currently, a promising novel treatment option in R/M SCCHN has emerged, termed immune checkpoint inhibitors. However, only a few patients presenting with R/M SCCHN have exhibited meaningful tumor regression with these agents. Therefore, novel agents are required to order improve the overall survival of patients with R/M SCCHN. Recently, we demonstrated that R/M SCCHN cells are highly sensitive to eribulin. In the present study, the effects of eribulin, paclitaxel and vinblastine were investigated in R/M SCCHN (OLC-01 and OSC-19) and locally advanced SCCHN (OSC-20) cells. Tumour-inhibitory activities of eribulin against R/M SCCHN were evaluated in orthotopic xenograft models. The data revealed that eribulin has sub-nM growth inhibitory activities in vitro against OLC-01 cells, and that it is more potent than paclitaxel and vinblastine. The reduced expression of Tubulin Beta 3 Class III (TUBB3) following treatment was correlated with a high sensitivity to eribulin. Histological analysis of OLC-01 cells in NOD-SCID mice demonstrated that they had a higher invasiveness in the tissue around the alveolar cancer when compared with the histology of OSC-19 cells, which has been reported in our previous study. Treatment with eribulin revealed marked inhibitory activities in vivo at 0.125 mg/kg against OLC-01 cells orthotopic xenografts. In conclusion, the results highlight the existence of invasive-type heterogeneity in R/M SCCHN with respect to eribulin sensitivity. Eribulin is already an approved clinical agent; therefore, the continued investigation of its preclinical antitumor attributes may contribute significantly to the future process of identifying novel uses of eribulin against R/M SCCHN.

Eribulin mesilate versus vinorelbine in women with locally recurrent or metastatic breast cancer: A randomised clinical trial

INTRODUCTION

The objective of this study was to evaluate the efficacy and safety of eribulin monotherapy, relative to vinorelbine, in Chinese women with locally recurrent/metastatic breast cancer (MBC).

METHODS

This phase III open-label, randomised, parallel-group, multicentre clinical trial enrolled patients with locally recurrent or MBC who had had 2-5 prior chemotherapy regimens, including an anthracycline and taxane) from September 26, 2013, to May 19, 2015. Women were randomised 1:1 to receive eribulin (1.4 mg/m², intravenously, on day 1 and day 8) or vinorelbine (25 mg/m², intravenously, on day 1, day 8 and day 15) every 21 days. The primary end-point was progression-free survival (PFS). Secondary end-points included objective response rate (ORR), duration of response and overall survival (OS).

RESULTS

Five hundred thirty women were randomised to receive eribulin (n = 264) or vinorelbine (n = 266). Improvement in PFS was observed with eribulin compared with vinorelbine (hazard ratio [HR]: 0.80, 95% confidence interval [CI]: 0.65-0.98, P = 0.036); median PFS was 2.8 months in both treatment arms. The median OS was 13.4 months with eribulin and 12.5 months with vinorelbine (HR: 1.03, 95% CI: 0.80-1.31, P = 0.838). The ORR was 30.7% (95% CI: 25.2%-36.6%) with eribulin and 16.9% (95% CI: 12.6%-22.0%) with vinorelbine (P < 0.001). Treatment-emergent adverse events leading to treatment discontinuation were less frequent with eribulin (7.2%) than with vinorelbine (14.0%).

CONCLUSIONS

Eribulin achieved statistically significantly superior PFS (and response rate) compared with vinorelbine in previously treated women with locally recurrent or MBC. Eribulin appeared to be better tolerated than vinorelbine, with no new safety signals observed.

TRIAL REGISTRATION

National Institutes of Health ClinicalTrials.gov registry, NCT02225470. Registered 05 August 2014- Retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT02225470?term=NCT02225470&rank=1.

Neurymenolide A, a Novel Mitotic Spindle Poison from the New Caledonian Rhodophyta Phacelocarpus neurymenioides

The marine α-pyrone macrolide neurymenolide A was previously isolated from the Fijian red macroalga, Neurymenia fraxinifolia, and characterized as an antibacterial agent against antibiotic-resistant strains that also exhibited moderate cytotoxicity in vitro against cancer cell lines. This compound was also shown to exhibit allelopathic effects on Scleractinian corals. However, to date no mechanism of action has been described in the literature. The present study showed, for the first time, the isolation of neurymenolide A from the New Caledonian Rhodophyta, Phacelocarpus neurymenioides. We confirmed the compound’s moderate cytotoxicity in vitro against several human cell lines, including solid and hematological malignancies. Furthermore, we combined fluorescence microscopy and flow cytometry to demonstrate that treatment of U-2 OS osteosarcoma human cells with neurymenolide A could block cell division in prometaphase by inhibiting the correct formation of the mitotic spindle, which induced a mitotic catastrophe that led to necrosis and apoptosis. Absolute configuration of the stereogenic center C-17 of neurymenolide A was deduced by comparison of the experimental and theoretical circular dichroism spectra. Since the total synthesis of this compound has already been described, our findings open new avenues in cancer treatment for this class of marine molecules, including a new source for the natural product.

Differential Morphological and Biochemical Recovery from Chemotherapy-Induced Peripheral Neuropathy Following Paclitaxel, Ixabepilone, or Eribulin Treatment in Mouse Sciatic Nerves

The reversibility of chemotherapy-induced peripheral neuropathy (CIPN), a disabling and potentially permanent side effect of microtubule-targeting agents (MTAs), is becoming an increasingly important issue as treatment outcomes improve. The molecular mechanisms regulating the variability in time to onset, severity, and time to recovery from CIPN between the common MTAs paclitaxel and eribulin are unknown. Previously (Benbow et al. in Neurotox Res 29:299-313, 2016), we found that after 2 weeks of a maximum tolerated dose (MTD) in mice, paclitaxel treatment resulted in severe reductions in axon area density, higher frequency of myelin abnormalities, and increased numbers of Schwann cell nuclei in sciatic nerves. Biochemically, eribulin induced greater microtubule-stabilizing effects than paclitaxel. Here, we extended these comparative MTD studies to assess the recovery from these short-term effects of paclitaxel, eribulin, and a third MTA, ixabepilone, over the course of 6 months. Paclitaxel induced a persistent reduction in axon area density over the entire 6-month recovery period, unlike ixabepilone- or eribulin-treated animals. The abundance of myelin abnormalities rapidly declined after cessation of all drugs but recovered most slowly after paclitaxel treatment. Paclitaxel- and ixabepilone- but not eribulin-treated animals exhibited increased Schwann cell numbers during the recovery period. Tubulin composition and biochemistry rapidly returned from MTD-induced levels of α-tubulin, acetylated α-tubulin, and end-binding protein 1 to control levels following cessation of drug treatment. Taken together, sciatic nerve axons recovered more rapidly from morphological effects in eribulin- and ixabepilone-treated animals than in paclitaxel-treated animals and drug-induced increases in protein expression levels following paclitaxel and eribulin treatment were relatively transient.

Prospective Analysis of Patients with Metastatic Breast Cancer receiving Eribulin Mesylate as Second or More Lines of Chemotherapy: An Indian Experience

BACKGROUND

Eribulin mesylate is a non-taxane microtubule inhibitor which can be used after anthracycline and taxane treatment in patients with metastatic breast cancer (MBC). The purpose of this study was to investigate the efficacy and safety of eribulin monotherapy in heavily pretreated patients with MBC.

METHODS

In this study, a total of 45 eligible patients with MBC who received eribulin in HCG Cancer Speciality Center from November 2014 to March 2016 were prospectively analyzed. Breslow (generalized Wilcoxon) survival analysis was carried out for progression-free survival and for overall survival. Patients were excluded if they had not taken treatment for 3 cycles and defaulted/expired during the treatment.

RESULTS

In this study, median age of patients was 52 years. A total of 27 (60%) patients had estrogen receptor and progesterone receptor (PR) positive primary tumors, whereas HER2 was overexpressed or amplified in 7 (15.6%); a triple negative subtype was recorded in 13 patients (28.9%). Regarding toxicity, 30 patients (66.67%) tolerated treatment well and 3 patients (6.67%) got anemia, 6 patients (13.3%) experienced neutropenia, and 7 (15.62%) patients had neurological toxicity. About 14 (31.1%) patients showed PR, 12 (26.7%) patients had stable disease (SD), whereas 19 (42.25%) patients showed progression disease (PD). Response evaluation at 6 cycles was possible in 18 patients and revealed that 4 (22.5%) patients showed PR, 10 (55.5%) patients had SD, whereas 4 (22.2%) patients had PD. Progression-free survival of the overall study population was 3.95 months.

CONCLUSIONS

Eribulin mesylate is efficacious and tolerable chemotherapy as second- and third-line treatment options for MBC.

Incidence and clinical parameters associated with eribulin mesylate-induced peripheral neuropathy

Eribulin mesylate is a microtubule-targeting agent that has been approved for the treatment of breast cancer and liposarcoma. Due to its novel mechanism of action, eribulin therapy induces a distinct profile of adverse events, including peripheral neuropathy. However, the incidence and risk of eribulin-related neurotoxicities are unclear. Here, we conducted a systematic search of PubMed and Embase from their inception to October 2017. Eligible studies included trials in which eribulin was intravenously administered at a standard dose of 1.4 mg/m² over 2-5 minutes on days 1 and 8 on a 21-day cycle. The events of all-grade and high-grade peripheral neuropathy were collected to calculate the overall incidence and relative risk (RR). A total of thirty-two studies containing 6129 subjects were included in this analysis. The incidences of all-grade and high-grade eribulin monotherapy-related peripheral neuropathy were 28% (95% confidence interval [CI], 24%-32%) and 4% (95% CI, 3%-5%), respectively. Subgroup analysis further revealed that a higher incidence of neurotoxicities was observed in patients with breast cancer and those with longer treatment duration. Moreover, eribulin-treated subjects had a significantly increased risk of all-grade (RR, 2.00; 95% CI, 1.70-2.35; p = 0.008) and high-grade (RR, 3.68; 95% CI, 2.30-5.89; p<0.001) neurotoxicities. Our results suggested that patients treated with eribulin had an increased risk of developing peripheral neuropathy.

Effect of eribulin on patients with metastatic breast cancer: multicenter retrospective observational study in Taiwan

Purpose

The aim of this study was to confirm the therapeutic role of eribulin on Taiwanese women with metastatic breast cancer.

Methods

This retrospective study examined 449 females who received eribulin between March 2014 and June 2017 at 14 hospitals in Taiwan for treatment of locally advanced or metastatic breast cancer.

Results

The survival rate at 24 months was 57.2% (95% CI 51.0–62.9%) and the median time to treatment failure (TTF) was 3.91 months (95% CI 3.45–3.94). A total of 175 patients (40.1%) received eribulin for fewer than 90 days and the others received it for 90 days or more. Eight patients (1.83%) had complete remission, 82 (18.8%) had partial remission, 202 (46.3%) had stable disease, and 144 (33.0%) had progressive disease (PD). Patients’ tumors with the luminal A subtype had a significantly better objective response rate. Kaplan–Meier analysis indicated that hormone receptor positivity, luminal A subtype, receipt of eribulin as the 1st to 3rd line therapy, and metastasis to fewer than 4 organs were significantly associated with longer TTF. Stepwise multivariate analysis showed that only receipt of eribulin as the 1st to 3rd line therapy was significantly associated with TTF (HR 1.49, p < 0.001). All toxicities were manageable and only 18 patients (4.1%) discontinued treatment due to adverse events.

Conclusions

Eribulin appears to have better efficacy and cause fewer adverse events, especially neutropenia, in Taiwanese women than Western women.

Bi-weekly eribulin therapy for metastatic breast cancer: a multicenter phase II prospective study (JUST-STUDY)

Background

This study aimed to investigate whether schedule modification is safe and effective in patients intolerant to the standard eribulin dose and schedule.

Methods

Patients with metastatic breast cancer (MBC) treated with both anthracycline and taxane and ≤ 3 prior regimens of chemotherapy for MBC received eribulin at the standard dose and schedule (1.4 mg/m² on days 1 and 8 of a 21-day cycle) in the first cycle; change of dosing schedule (1.4 mg/m² on days 1 and 15 of a 28-day cycle) was determined by change in neutrophil count, platelet count, aspartate aminotransferase, alanine aminotransferase, total bilirubin, serum creatinine, and non-hematological toxicity on day 8 of the first cycle or day 1 of the second cycle. Clinical benefit rate (CBR; primary endpoint), time to treatment failure (TTF), overall survival (OS), and safety were evaluated.

Results

Of the 88 patients who were enrolled and received standard eribulin therapy in the first cycle, 42 patients were moved to the bi-weekly therapy group and 40 continued standard therapy. In the bi-weekly and standard therapy groups, mean relative dose intensity was 62.7 and 90.9%, CBR was 31.0 and 25.0%, median TTF was 81.5 and 75 days, and OS was 523 and 412 days, respectively. Neither group reported severe adverse events.

Conclusion

This is the first study to show that a bi-weekly eribulin schedule is tolerable and has comparable efficacy in patients intolerant to the standard eribulin schedule.

Clinical trial registration

University Hospital Medical Information Network (UMIN) Center (ID: UMIN 000008491).

Electronic supplementary material

The online version of this article (10.1007/s12282-018-0843-y) contains supplementary material, which is available to authorized users.

Eribulin therapy for the treatment of patients with advanced soft tissue sarcoma

Eribulin is a structurally simplified, synthetic macrocyclic ketone analog of halichondrin B, which is a natural, polyether macrolide derived from marine sponges. Eribulin exerts its cytotoxicity by its unique microtubule dynamics inhibitory action. Eribulin was approved in 2010 by the US FDA as a third-line therapy for metastatic breast cancer patients previously treated with an anthracycline and a taxane. In 2016, it was approved for treatment of metastatic liposarcoma for patients who have progressed with anthracycline treatment. In this article, we review the pharmacokinetics, mechanism of action of eribulin with focus on preclinical and clinical data in sarcoma and also the role of miRNAs in soft tissue sarcomas.

Eribulin efficacy based on type of metastatic site: a real-life study in heavily pretreated metastatic breast cancer

AIM

The halichondrin B analog, eribulin, exerts an anticancer effect, as reported by several clinical and real-life studies on metastatic breast cancer patients. Here, we evaluated efficacy and safety of eribulin, focusing on response to treatment per metastasis type.

PATIENTS & METHODS

This monocentric, real-life study was conducted on 31 heavily pretreated patients with metastatic breast cancer.

RESULTS

The median progression-free survival and overall survival were 2.0 and 5.5 months, respectively. All patients (12.9%) responding to eribulin were treated in fourth-line setting. Considering response per metastasis type, bone lesions (13.6%) responded more frequently than other metastases to eribulin.

CONCLUSION

Eribulin exhibited a good overall response rate, with the highest response observed for bone metastases.

Managing sarcoma: where have we come from and where are we going?

Sarcomas are a heterogeneous group of neoplasms of mesenchymal origin. Approximately 80% arise from soft tissue and 20% originate from bone. To date more than 100 sarcoma subtypes have been identified and they vary in molecular characteristics, pathology, clinical presentation and response to treatment. While sarcomas represent <1% of adult cancers, they account for approximately 21% of paediatric malignancies and thus pose some of the greatest risks of mortality and morbidity in children and young adults. Metastases occur in one-third of all patients and approximately 10-20% of sarcomas recur locally. Surgery in combination with preoperative and postoperative therapies is the primary treatment for localized sarcoma tumours and is the most promising curative possibility. Metastasized sarcomas, on the other hand, are treated primarily with single-agent or combination chemotherapy, but this rarely leads to a complete and robust response and often becomes a palliative form of treatment. The heterogeneity of sarcomas results in variable responses to current generalized treatment strategies. In light of this and the lack of curative strategies for metastatic and unresectable sarcomas, there is a need for novel subtype-specific treatment strategies. With the more recent understanding of the molecular mechanisms underlying the pathogenesis of some of these tumours, the treatment of sarcoma subtypes with targeted therapies is a rapidly evolving field. This review discusses the current management of sarcomas as well as promising new therapies that are currently underway in clinical trials.

Synergistic effect of eribulin and CDK inhibition for the treatment of triple negative breast cancer

Activation of CDK2 in triple negative breast cancer (TNBC) can contribute to non-canonical phosphorylation of a TGFβ signaling component, Smad3, promoting cell proliferation and migration. Inhibition of CDK2 was shown to decrease breast cancer oncogenesis. Eribulin chemotherapy was used effectively in the treatment of TNBC. To this end, we tested therapeutic efficacy of a novel CDK2/9 inhibitor, CYC065, eribulin, and the combination of CYC065 and eribulin in 3 different TNBC cell lines, and an in vivo xenograft model. Specifically, we characterized cell proliferation, apoptosis, migration, cell cycle associated protein expression, treatment-related transcription factor activity, and tumor growth in TNBC. Treatment with CYC065 and eribulin in combination had a superior effect on decreasing cell proliferation, inducing apoptosis, and inhibiting migration in TNBC cell lines in vitro. Combination therapy inhibited non-canonical Smad3 phosphorylation at the T179 site in the protein linker region, and resulted in increased p15 and decreased c-myc expression. In a transcription factor array, combination treatment significantly increased activity of AP1 and decreased activity of factors including NFκB, SP1, E2F, and SMAD3. In an in vivo xenograft model of TNBC, individual and combination treatments resulted in a decrease in both tumor volume and mitotic indices. Taken together, these studies highlight the potential of this novel drug combination, CYC065 and eribulin, to suppress the growth of TNBC cells in vitro and in vivo, warranting further clinical investigation.

Eribulin alone or in combination with the PLK1 inhibitor BI 6727 triggers intrinsic apoptosis in Ewing sarcoma cell lines

In this study, we investigated the molecular mechanisms of eribulin-induced cell death and its therapeutic potential in combination with the PLK1 inhibitor BI 6727 in Ewing sarcoma (ES). Here, we show that eribulin triggers cell death in a dose-dependent manner in a panel of ES cell lines. In addition, eribulin at subtoxic, low nanomolar concentrations acts in concert with BI 6727 to induce cell death and to suppress long-term clonogenic survival. Mechanistic studies reveal that eribulin monotherapy at cytotoxic concentrations and co-treatment with eribulin at subtoxic concentrations together with BI 6727 arrest cells in the M phase of the cell cycle prior to the onset of cell death. This mitotic arrest is followed by increased phosphorylation of BCL-2 and BCL-x_L as well as downregulation of MCL-1, suggesting inactivation of these antiapoptotic BCL-2 family proteins. Consistently, eribulin monotherapy and eribulin/BI 6727 co-treatment trigger activation of BAX, a key proapoptotic BCL-2 family protein, and increase proteolytic activation of caspase-9 and -3. Importantly, overexpression of BCL-2 or addition of the broad-range caspase inhibitor zVAD.fmk significantly rescue eribulin- as well as eribulin/BI 6727-induced cell death. Together, these findings demonstrate that eribulin induces cell death via the intrinsic pathway of apoptosis in ES cells, both alone at cytotoxic concentrations and in combination with BI 6727 at subtoxic concentrations. Thus, our study highlights the therapeutic potential of eribulin for the treatment of ES alone or in rational combination therapies.

Recent Advances in the Development of Antineoplastic Agents Derived from Natural Products

Through years of evolutionary selection pressures, organisms have developed potent toxins that coincidentally have marked antineoplastic activity. These natural products have been vital for the development of multiagent treatment regimens currently employed in cancer chemotherapy, and are used in the treatment of a variety of malignancies. Therefore, this review catalogs recent advances in natural product-based drug discovery via the examination of mechanisms of action and available clinical data to highlight the utility of these novel compounds in the burgeoning age of precision medicine. The review also highlights the recent development of antibody-drug conjugates and other immunotoxins, which are capable of delivering highly cytotoxic agents previously deemed too toxic to elicit therapeutic benefit preferentially to neoplastic cells. Finally, the review examines natural products not currently used in the clinic that have novel mechanisms of action, and may serve to supplement current chemotherapeutic protocols.

Eribulin in the management of inoperable soft-tissue sarcoma: patient selection and survival

Patients diagnosed with metastatic soft-tissue sarcoma (STS) have a poor prognosis. Additionally, after failure of first-line therapy, there are relatively few treatment options from which to choose. The novel tubulin-binding drug, eribulin, with a unique mechanism of action from taxanes or vinca alkaloids, has shown clinical activity in several different types of cancers. Eribulin has been approved by the US Food and Drug Administration (FDA) for patients with metastatic breast cancer previously treated with an anthracycline or a taxane and has recently been FDA approved for patients with unresectable or metastatic liposarcoma who have failed a previous anthracycline regimen. Here, we review current standard treatments of STS, a background of eribulin, the studies that have propelled eribulin to FDA approval for liposarcoma, and future directions of the drug. The benefits of eribulin in STS are discussed in detail, especially with regard to the recent pivotal Phase III study comparing eribulin to dacarbazine for leiomyosarcoma and adipocytic sarcoma.

Anti-Microtubule Drugs

Small molecule drugs that target microtubules (MTs), many of them natural products, have long been important tools in the MT field. Indeed, tubulin (Tb) was discovered, in part, as the protein binding partner of colchicine. Several anti-MT drug classes also have important medical uses, notably colchicine, which is used to treat gout, familial Mediterranean fever (FMF), and pericarditis, and the vinca alkaloids and taxanes, which are used to treat cancer. Anti-MT drugs have in common that they bind specifically to Tb in the dimer, MT or some other form. However, their effects on polymerization dynamics and on the human body differ markedly. Here we briefly review the most-studied molecules, and comment on their uses in basic research and medicine. Our focus is on practical applications of different anti-MT drugs in the laboratory, and key points that users should be aware of when designing experiments. We also touch on interesting unsolved problems, particularly in the area of medical applications. In our opinion, the mechanism by which any MT drug cures or treats any disease is still unsolved, despite decades of research. Solving this problem for particular drug-disease combinations might open new uses for old drugs, or provide insights into novel routes for treatment.

Antimitotic drugs in the treatment of cancer

Cancer is a complex disease since it is adaptive in such a way that it can promote proliferation and invasion by means of an overactive cell cycle and in turn cellular division which is targeted by antimitotic drugs that are highly validated chemotherapy agents. However, antimitotic drug cytotoxicity to non-tumorigenic cells and multiple cancer resistance developed in response to drugs such as taxanes and vinca alkaloids are obstacles faced in both the clinical and basic research field to date. In this review, the classes of antimitotic compounds, their mechanisms of action and cancer cell resistance to chemotherapy and other limitations of current antimitotic compounds are highlighted, as well as the potential of novel 17-β estradiol analogs as cancer treatment.

A phase I combination dose-escalation study of eribulin mesylate and gemcitabine in patients with advanced solid tumours: a study of the Princess Margaret Consortium

BACKGROUND

Eribulin mesylate is a synthetic microtubule inhibitor that showed cytotoxic synergy in combination with gemcitabine preclinically. This combination was assessed in a Phase I dose-finding trial in patients diagnosed with advanced solid tumours who had received up to two prior chemotherapy regimens for metastatic disease (CP cohort).

METHODS

Dose escalation was performed in a 3+3 design to identify the recommended phase II dose (RP2D). Two additional expansion cohorts in women with gynaecologic cancers at the RP2D (G), and further dose escalation of metastatic chemotherapy-naive patients (CN), were evaluated.

RESULTS

45 patients were treated: 21 (CP), 10 (G) and 14 (CN). The initial combination of eribulin and gemcitabine was administered on days 1, 8, and 15 of a 28-day cycle; however, due to 2 out of 6 dose-limiting haematological toxicities at the first dose level, a reduced dose-intense schedule was assessed. The RP2D was defined at 1.0 mg m(-2) eribulin and 1000 mg m(-2) gemcitabine day 1 and 8 q3 weeks. No other significant toxicities were observed in the G expansion cohort. Neutropenia prevented further dose escalation in the CN cohort. Objective responses were seen in all three cohorts - 2/21 (CP), 1/10 (G) and 2/14 (CN).

CONCLUSIONS

The combination of eribulin and gemcitabine was well tolerated at the RP2D.

Pharmacokinetics of eribulin mesylate in cancer patients with normal and impaired renal function

Purpose

To evaluate the effect of renal impairment on eribulin mesylate pharmacokinetics following a single dose in adults with advanced solid tumors.

Methods

Patients were grouped by renal function: moderate impairment (creatinine clearance [CrCl] 30–50 mL/min), severe impairment (CrCl 15–29 mL/min), or normal (CrCl ≥80 mL/min). During each 21-day cycle, eribulin mesylate doses (days 1 and 8) were administered intravenously: moderate, 1.1 mg/m² (except cycle 1 day 1, 1.4 mg/m²); severe, 0.7 mg/m²; normal, 1.4 mg/m².

Results

Nineteen patients were enrolled (normal, n = 6; moderate, n = 7; severe, n = 6). Renal impairment was associated with an increased mean dose-normalized area under the concentration–time curve (ratios for moderate/normal and severe/normal: 1.49; 90 % confidence interval [CI] 0.9, 2.45). CrCl and renal function correlated positively, with a numerically small slope (0.0184; 90 % CI −0.00254, 0.0394). A simulated dose reduction to eribulin 1.1 mg/m² in patients with moderate or severe renal impairment achieved the same exposure as 1.4 mg/m² in those with normal renal function. All groups had similar toxicity profiles, with no unexpected adverse events.

Conclusions

Renal impairment decreased eribulin clearance and increased exposure. Pharmacokinetic evaluation supports an eribulin dose reduction to 1.1 mg/m² in patients with moderate or severe renal impairment.

ClinicalTrials.gov Identifier

NCT01418677.

Eribulin in Cancer Treatment

Halichondrin B is a complex, natural, polyether macrolide derived from marine sponges. Eribulin is a structurally-simplified, synthetic, macrocyclic ketone analogue of Halichondrin B. Eribulin was approved by United States Food and Drug Administration in 2010 as a third-line therapy for metastatic breast cancer patients who have previously been treated with an anthracycline and a taxane. It has a unique microtubule dynamics inhibitory action. Phase III studies have either been completed or are currently ongoing in breast cancer, soft tissue sarcoma, and non-small cell lung cancer. Phase I and II studies in multiple cancers and various combinations are currently ongoing. This article reviews the available information on eribulin with respect to its clinical pharmacology, pharmacokinetics, pharmacodynamics, mechanism of action, metabolism, preclinical studies, and with special focus on clinical trials.