er-086526 and ixabepilone

Ixabepilone is now a Food and Drug Administration-approved therapeutic option for patients with metastatic breast cancer (MBC) whose disease has progressed despite prior anthracycline and taxane therapy. We conducted a systematic review and meta-analysis to systematically evaluate the efficacy and safety of ixabepilone for treating metastatic breast cancer.. A systematic review and meta-analysis were conducted. Randomized controlled studies applying ixabepilone for treating MBC were included. The primary outcome was Overall Survival (OS). The authors of primary articles were contacted and methodological quality was evaluated. Subgroups were drawn based on intervention measures; heterogeneity and bias were discussed.. Eight studies with 5247 patients were included. Compared with a weekly schedule, a triweekly schedule of ixabepilone was better at improving overall response rate (ORR), while there were no differences in improving OS and progression-free survival (PFS). Ixabepilone plus capecitabine was superior to capecitabine monotherapy in improving OS, PFS and ORR. Paclitaxel was more effective than ixabepilone in terms of OS and PFS. There was no difference in the improvement of ORR, clinical benefit rate (CBR) and disease control rate (DCR) between ixabepilone and eribulin.. Current evidence suggests that a triweekly schedule of ixabepilone is more effective than weekly dosing in improving ORR. Use of ixabepilone in combination with capecitabine possesses superior clinical efficacy to the use of capecitabine alone. Paclitaxel was more effective than ixabepilone in terms of OS and PFS. The efficacy and safety between ixabepilone and eribulin were identical.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Capecitabine; Drug Administration Schedule; Epothilones; Female; Furans; Humans; Ketones; Paclitaxel; Survival Analysis; Treatment Outcome

Health-related quality of life (HRQoL) enhances understanding of treatment effects that impact clinical decision-making. Although the primary end-point was not achieved, the BEACON (BrEAst Cancer Outcomes with NKTR-102) trial established etirinotecan pegol, a long-acting topoisomerase-1 (TOP1) inhibitor, as a promising therapeutic for patients with advanced/metastatic breast cancer (MBC) achieving clinically meaningful benefits in median overall survival (OS) for patients with stable brain metastases, with liver metastases or ≥ 2 sites of metastatic disease compared to treatment of physician's choice (TPC). Reported herein are the findings from the preplanned secondary end-point of HRQoL.. HRQoL, assessed by European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30) (version 3.0) supplemented by the breast cancer-specific Quality of Life Questionnaire (QLQ-BR23), was evaluated post randomisation in 733 of 852 patients with either anthracycline-, taxane- and capecitabine-pretreated locally recurrent or MBC randomised to etirinotecan pegol (n = 378; 145 mg/m. Differences were seen favouring etirinotecan pegol up to 32 weeks for global health status (GHS) and physical functioning scales (P < 0.02); numerical improvement was reported in other functional scales. The findings from HRQoL symptom scales were consistent with adverse event profiles; etirinotecan pegol was associated with worsening gastrointestinal symptoms whereas TPC was associated with worsened dyspnoea and other systemic side-effects. Analysis of GHS and physical functioning at disease progression showed a decline in HRQoL in both treatment arms, with a mean change from baseline of -9.4 and -10.8 points, respectively.. There was evidence of benefit associated with etirinotecan pegol compared with current standard of care agents in multiple HRQoL measurements, including global health status and physical functioning, despite worse gastrointestinal symptoms (e.g. diarrhoea). Patients in both arms had a decline in HRQoL at disease progression.. NCT01492101.

Topics: Activities of Daily Living; Adult; Aged; Aged, 80 and over; Albumins; Anorexia; Antineoplastic Agents; Body Image; Bone Neoplasms; Brain Neoplasms; Breast Neoplasms; Cancer Pain; Deoxycytidine; Docetaxel; Dyspnea; Epothilones; Fatigue; Female; Furans; Gemcitabine; Health Status; Heterocyclic Compounds, 4 or More Rings; Humans; Ketones; Liver Neoplasms; Lung Neoplasms; Middle Aged; Nausea; Paclitaxel; Polyethylene Glycols; Quality of Life; Reproductive Health; Sleep Initiation and Maintenance Disorders; Taxoids; Vinblastine; Vinorelbine; Vomiting

Peripheral neuropathy is a common toxicity associated with tubulin-targeted chemotherapeutic agents. This Phase II study compares the incidence and severity of neuropathy associated with eribulin mesylate or ixabepilone in metastatic breast cancer (MBC). The primary objective was to assess the incidence of neuropathy; the study was designed to detect a difference in neuropathy rate of 35 % for eribulin versus 63 % for ixabepilone (odds ratio 0.316, 80 % power, 0.05 two-sided significance level). Eligibility criteria included: MBC; prior taxane therapy; at least one chemotherapy for advanced disease; no or minimal pre-existing neuropathy (Grade 0 or 1). The intent-to-treat population comprised 104 patients randomized (1:1) to eribulin mesylate (1.4 mg/m(2), 2-5 min intravenous on days 1 and 8) or ixabepilone (40 mg/m(2), 3 h intravenous on day 1) on a 21-day cycle. 101 patients in the safety population received a median of 5.0 eribulin and 3.5 ixabepilone cycles. Incidence of neuropathy (any grade) was 33.3 and 48.0 %, and peripheral neuropathy was 31.4 and 44.0 % for eribulin and ixabepilone, respectively. After controlling for pre-existing neuropathy and number of prior chemotherapies, these differences were not significant. Compared with ixabepilone, fewer patients receiving eribulin discontinued treatment due to neuropathy (3.9 vs. 18.0 %) or adverse events (AEs) in general (11.8 vs. 32.0 %). Time to onset of neuropathy was 35.9 weeks for eribulin and 11.6 weeks for ixabepilone, and time to resolution was 48 versus 10 weeks, respectively; other AEs were comparable. Objective responses were 15.4 versus 5.8 % and clinical benefit rates were 26.9 versus 19.2 %. In conclusion, after controlling for pre-existing neuropathy and number of prior chemotherapies, the differences in the incidence of neuropathy with eribulin and ixabepilone were not statistically significant. Onset of neuropathy tended to occur later with eribulin and resolve later.

Topics: Adult; Breast Neoplasms; Epothilones; Female; Furans; Humans; Ketones; Middle Aged; Neoplasm Metastasis; Peripheral Nervous System Diseases; Survival Rate

Evidence shows that the anticancer effects of microtubule targeting agents are not due solely to their antimitotic activities but also their ability to impair microtubule-dependent oncogenic signalling.. The effects of microtubule targeting agents on regulators of TGF-β-induced epithelial-to-mesenchymal transition (EMT) were evaluated in breast cancer cell lines using high content imaging, gene and protein expression, siRNA-mediated knockdown and chromatin immunoprecipitation.. Microtubule targeting agents rapidly and differentially alter the expression of Snail and Slug, key EMT-promoting transcription factors in breast cancer. Eribulin, vinorelbine and in some cases, ixabepalone, but not paclitaxel, inhibited TGF-β-mediated Snail expression by impairing the microtubule-dependent nuclear localisation of Smad2/3. In contrast, eribulin and vinorelbine promoted a TGF-β-independent increase in Slug in cells with low Smad4. Mechanistically, microtubule depolymerisation induces c-Jun, which consequently increases Slug expression in cells with low Smad4.. These results identify a mechanism by which eribulin-mediated microtubule disruption could reverse EMT in preclinical models and in patients. Furthermore, high Smad4 levels could serve as a biomarker of this response. This study highlights that microtubule targeting drugs can exert distinct effects on the expression of EMT-regulating transcription factors and that identifying differences among these drugs could lead to their more rational use.

Topics: Breast Neoplasms; Cell Line, Tumor; Cell Nucleus; Chromatin Immunoprecipitation; Epithelial-Mesenchymal Transition; Epothilones; Female; Furans; Gene Expression; Genes, jun; Humans; Ketones; Microtubules; Paclitaxel; Smad2 Protein; Smad3 Protein; Smad4 Protein; Snail Family Transcription Factors; Transforming Growth Factor beta; Tubulin Modulators; Vinorelbine

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.

Topics: Animals; Antineoplastic Agents; Disease Models, Animal; Epothilones; Female; Furans; Intermediate Filaments; Ketones; Mice; Mice, Inbred BALB C; Microtubule-Associated Proteins; Myelin Sheath; Paclitaxel; Recovery of Function; S100 Proteins; Schwann Cells; Sciatic Neuropathy; Time Factors; Tubulin

Chemotherapy-induced peripheral neuropathy is a dose-limiting side effect of many antineoplastic agents, but the mechanisms underlying the toxicities are unclear. At their MTDs, the microtubule-binding drugs paclitaxel and ixabepilone induce more severe neuropathy in mice relative to eribulin mesylate, paralleling their toxicity profiles in clinic. We hypothesized that the severity of their neurotoxic effects might be explained by the levels at which they accumulate in the peripheral nervous system. To test this hypothesis, we compared their pharmacokinetics and distribution in peripheral nerve tissue. After administration of a single intravenous dose, each drug was rapidly cleared from plasma but all persisted in the dorsal root ganglia (DRG) and sciatic nerve (SN) for up to 72 hours. Focusing on paclitaxel and eribulin, we performed a 2-week MTD-dosing regimen, followed by a determination of drug pharmacokinetics, tissue distribution, and multiple functional measures of peripheral nerve toxicity for 4 weeks. Consistent with the acute dosing study, both drugs persisted in peripheral nervous tissues for weeks, in contrast to their rapid clearance from plasma. Notably, although eribulin exhibited greater DRG and SN penetration than paclitaxel, the neurotoxicity observed functionally was consistently more severe with paclitaxel. Overall, our results argue that sustained exposure of microtubule-binding chemotherapeutic agents in peripheral nerve tissues cannot by itself account for their associated neurotoxicity. Cancer Res; 76(11); 3332-9. ©2016 AACR.

Topics: Animals; Apoptosis; Blotting, Western; Cell Proliferation; Dose-Response Relationship, Drug; Electrophysiology; Epothilones; Female; Furans; Ganglia, Spinal; Ketones; Mice; Mice, Inbred BALB C; Microtubules; Paclitaxel; Peripheral Nervous System Diseases; Sciatic Nerve; Time Factors; Tissue Distribution; Tubulin Modulators

Peripheral neuropathy is a serious, dose-limiting side effect of cancer treatment with microtubule-targeting drugs. Symptoms present in a "stocking-glove" distribution, with longest nerves affected most acutely, suggesting a length-dependent component to the toxicity. Axonal transport of ATP-producing mitochondria along neuronal microtubules from cell body to synapse is crucial to neuronal function. We compared the effects of the drugs paclitaxel and ixabepilone that bind along the lengths of microtubules and the drugs eribulin and vincristine that bind at microtubule ends, on mitochondrial trafficking in cultured human neuronal SK-N-SH cells and on axonal transport in mouse sciatic nerves. Antiproliferative concentrations of paclitaxel and ixabepilone significantly inhibited the anterograde transport velocity of mitochondria in neuronal cells, whereas eribulin and vincristine inhibited transport only at significantly higher concentrations. Confirming these observations, anterogradely transported amyloid precursor protein accumulated in ligated sciatic nerves of control and eribulin-treated mice, but not in paclitaxel-treated mice, indicating that paclitaxel inhibited anterograde axonal transport, whereas eribulin did not. Electron microscopy of sciatic nerves of paclitaxel-treated mice showed reduced organelle accumulation proximal to the ligation consistent with inhibition of anterograde (kinesin based) transport by paclitaxel. In contrast, none of the drugs significantly affected retrograde (dynein based) transport in neuronal cells or mouse nerves. Collectively, these results suggest that paclitaxel and ixabepilone, which bind along the lengths and stabilize microtubules, inhibit kinesin-based axonal transport, but not dynein-based transport, whereas the microtubule-destabilizing drugs, eribulin and vincristine, which bind preferentially to microtubule ends, have significantly less effect on all microtubule-based axonal transport. Cancer Res; 76(17); 5115-23. ©2016 AACR.

Topics: Animals; Antineoplastic Agents; Axonal Transport; Epothilones; Furans; Humans; Ketones; Mice; Microtubules; Mitochondria; Neurons; Paclitaxel; Peripheral Nervous System Diseases; Sciatic Nerve; Tubulin Modulators; Vincristine

Chemotherapy-induced peripheral neuropathy (CIPN) is a serious, painful and dose-limiting side effect of cancer drugs that target microtubules. The mechanisms underlying the neuronal damage are unknown, but may include disruption of fast axonal transport, an essential microtubule-based process that moves cellular components over long distances between neuronal cell bodies and nerve terminals. This idea is supported by the "dying back" pattern of degeneration observed in CIPN, and by the selective vulnerability of sensory neurons bearing the longest axonal projections. In this study, we test the hypothesis that microtubule-targeting drugs disrupt fast axonal transport using vesicle motility assays in isolated squid axoplasm and a cell-free microtubule gliding assay with defined components. We compare four clinically-used drugs, eribulin, vincristine, paclitaxel and ixabepilone. Of these, eribulin is associated with a relatively low incidence of severe neuropathy, while vincristine has a relatively high incidence. In vesicle motility assays, we found that all four drugs inhibited anterograde (conventional kinesin-dependent) fast axonal transport, with the potency being vincristine=ixabepilone>paclitaxel=eribulin. Interestingly, eribulin and paclitaxel did not inhibit retrograde (cytoplasmic dynein-dependent) fast axonal transport, in contrast to vincristine and ixabepilone. Similarly, vincristine and ixabepilone both exerted significant inhibitory effects in an in vitro microtubule gliding assay consisting of recombinant kinesin (kinesin-1) and microtubules composed of purified bovine brain tubulin, whereas paclitaxel and eribulin had negligible effects. Our results suggest that (i) inhibition of microtubule-based fast axonal transport may be a significant contributor to neurotoxicity induced by microtubule-targeting drugs, and (ii) that individual microtubule-targeting drugs affect fast axonal transport through different mechanisms.

Topics: Animals; Antineoplastic Agents; Axonal Transport; Axons; Dose-Response Relationship, Drug; Epothilones; Furans; Ketones; Kinesins; Loligo; Microtubules; Paclitaxel; Peripheral Nervous System Diseases; Time Factors; Tubulin; Tubulin Modulators; Vincristine

Eribulin was FDA approved in 2012 as a treatment for patients with MBC who have previously received at least two prior chemotherapy regimens. The aim of this analysis was to assess the cost effectiveness of eribulin versus the three most commonly utilized drugs (TPC) in the EMBRACE trial: vinorelbine, gemcitabine, and capecitabine (X); and to other branded FDA approved drugs: ixabepilone (I), liposomal-doxorubicin (D), and nab-paclitaxel. We created a decision-analytical and a Markov model using clinical data from the EMBRACE trial. Health utilities were derived from the published literature. Costs for drug acquisition, physician visits, and laboratory tests were obtained from Medicare Services Drug Payment Table and Physician Fee Schedule and are represented in 2012 USD. Life-years saved (LY), quality-adjusted life years (QALY), and incremental cost effectiveness ratio (ICER) were calculated. Eribulin added 0.208 LY and 0.119 QALY with an incremental cost over TPC of $25,458, and therefore an ICER of $213,742 per QALY. The main drivers of the model were drug cost, PFS, OS, and health utility values. The results of the model were robust in sensitivity analyses. Relative to I, D, A, and X, the ICER for eribulin was $76,823, $109,283, $129,773, and $167,267, respectively. Even with a more contemporary willingness-to-pay threshold of approximately $120,000 per QALY, eribulin was not found to be cost effective in the treatment of MBC relative to TPC; relative to some more expensive branded drugs, eribulin appears to be cost effective.

Topics: Albumins; Antineoplastic Agents; Breast Neoplasms; Capecitabine; Cost-Benefit Analysis; Decision Making, Computer-Assisted; Deoxycytidine; Disease-Free Survival; Doxorubicin; Drug Resistance, Neoplasm; Epothilones; Female; Fluorouracil; Furans; Humans; Ketones; Markov Chains; Neoplasm Metastasis; Paclitaxel; Quality of Life; Treatment Outcome

Chemotherapy-induced neurotoxicity is a significant problem associated with successful treatment of many cancers. Tubulin is a well-established target of antineoplastic therapy; however, tubulin-targeting agents, such as paclitaxel and the newer epothilones, induce significant neurotoxicity. Eribulin mesylate, a novel microtubule-targeting analogue of the marine natural product halichondrin B, has recently shown antineoplastic activity, with relatively low incidence and severity of neuropathy, in metastatic breast cancer patients. The mechanism of chemotherapy-induced neuropathy is not well understood. One of the main underlying reasons is incomplete characterization of pathology of peripheral nerves from treated subjects, either from patients or preclinically from animals. The current study was conducted to directly compare, in mice, the neuropathy-inducing propensity of three drugs: paclitaxel, ixabepilone, and eribulin mesylate. Because these drugs have different potencies and pharmacokinetics, we compared them on the basis of a maximum tolerated dose (MTD). Effects of each drug on caudal and digital nerve conduction velocity, nerve amplitude, and sciatic nerve and dorsal root ganglion morphology at 0.25 × MTD, 0.5 × MTD, 0.75 × MTD, and MTD were compared. Paclitaxel and ixabepilone, at their respective MTDs, produced significant deficits in caudal nerve conduction velocity, caudal amplitude and digital nerve amplitudes, as well as moderate to severe degenerative pathologic changes in dorsal root ganglia and sciatic nerve. In contrast, eribulin mesylate produced no significant deleterious effects on any nerve conduction parameter measured and caused milder, less frequent effects on morphology. Overall, our findings indicate that eribulin mesylate induces less neuropathy in mice than paclitaxel or ixabepilone at equivalent MTD-based doses.

Topics: Animals; Antineoplastic Agents, Phytogenic; Body Weight; Dose-Response Relationship, Drug; Epothilones; Female; Furans; Ganglia, Spinal; Ketones; Mesylates; Mice; Mice, Inbred BALB C; Neural Conduction; Paclitaxel; Polyneuropathies; Rats; Sciatic Nerve; Tubulin Modulators