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

A phase Ib/II study of eribulin in combination with cyclophosphamide in patients with advanced breast cancer

PURPOSE

We hypothesized that eribulin combined with cyclophosphamide (EC) would be an effective combination with tolerable toxicity for the treatment of advanced breast cancer (ABC).

METHODS

Patients with histologically confirmed metastatic or unresectable ABC with any number of prior lines of therapy were eligible to enroll. In the dose escalation cohort, dose level 0 was defined as eribulin 1.1 mg/m2 and cyclophosphamide 600 mg/m2, and dose level 1 was defined as eribulin 1.4 mg/m2 and cyclophosphamide 600 mg/m2. Eribulin was given on days 1 and 8 and cyclophosphamide on day 1 of a 21-day cycle. In the dose expansion cohort, enrollment was expanded at dose level 1. The primary objective was clinical benefit rate (CBR), and secondary objectives were response rate (RR), duration of response (DOR), progression-free survival (PFS), and safety.

RESULTS

No dose-limiting toxicities were identified in the dose escalation cohort (n = 6). In the dose expansion cohort, an additional 38 patients were enrolled for a total of 44 patients, including 31 patients (70.4%) with hormone receptor-positive (HR +)/HER2- disease, 12 patients (27.3%) with triple-negative breast cancer (TNBC), and 1 patient (2.3%) with HR + /HER2 + disease. Patients had a median age of 56 years (range 33-82 years), 1 prior line of hormone therapy (range 0-6), and 2 prior lines of chemotherapy (range 0-7). CBR was 79.5% (35/44; 7 partial response, 28 stable disease) and the median DOR was 16.4 weeks (range 13.8-21.1 weeks). Median PFS was 16.4 weeks (95% CI: 13.8-21.1 weeks). The most common grade 3/4 adverse event was neutropenia (47.7%, n = 21). Fourteen of 26 patients (53.8%) with circulating tumor cell (CTC) data were CTC-positive ([Formula: see text] 5 CTC/7.5 mL) at baseline. Median PFS was shorter in patients who were CTC-positive vs. negative (13.1 vs 30.6 weeks, p = 0.011).

CONCLUSION

In heavily pretreated patients with ABC, treatment with EC resulted in an encouraging CBR of 79.5% and PFS of 16.4 weeks, which compares favorably to single-agent eribulin. Dose reduction and delays were primarily due to neutropenia. The contribution of cyclophosphamide to eribulin remains unclear but warrants further evaluation. NCT01554371.

Phase II trial of biweekly administration with eribulin after three cycles of induction therapy in hormone receptor-positive, HER2-negative metastatic breast cancer (JACCRO BC-03)

PURPOSE

Metastatic breast cancer (MBC) is usually incurable; treatment aims to maximize patients' function and quality of life (QOL). Eribulin is a standard treatment in patients with MBC pretreated with anthracycline and taxane; however, the best administration schedule is unknown.

METHODS

In this prospective phase II trial of patients with luminal MBC, we administered biweekly eribulin to patients who completed a three-cycle induction treatment.

RESULTS

Sixty patients with hormone-receptor-positive and HER2-negative MBC were enrolled; 40 obtained stable disease (SD) or better efficacy after induction therapy, after which they were switched to biweekly maintenance administration. The median progression-free survival (PFS) in patients who switched to maintenance therapy was 15.21 weeks (95% CI 9.71-22.14), starting on the first day of maintenance therapy. Overall survival (OS) in patients who switched to maintenance therapy was 21.39 months (95% CI 18.89-32.89). PFS and OS in the whole population starting from the registration date were 19.00 weeks (95% CI 17.00-25.00) and 21.52 months (95% CI 16.23-24.25), respectively. PFS from the enrollment date for patients who received maintenance therapy was 25.29 weeks (95% CI 19.14-32.14). Patients who achieved complete response or partial response during induction therapy had significantly longer PFS compared to patients with SD.

CONCLUSION

The efficacy of biweekly administration of eribulin at maintenance was nonsignificant. However, less frequent visits are convenient, and reduced dose intensity improves safety. Biweekly administration, besides dose reduction, could be an acceptable option for patients who are unable to maintain a standard regimen.

Novel RAF/MEK inhibitor CH5126766/VS-6766 has efficacy in combination with eribulin for the treatment of triple-negative breast cancer

Various molecular‐targeting drugs have markedly improved the treatment of patients with breast cancer. As yet, therapies for triple‐negative breast cancer are mainly cytotoxic agents. To investigate the novel therapy for triple‐negative breast cancer, we herein examined the effects of a new combination therapy comprising a RAF/MEK inhibitor CH5126766, also known as VS‐6766, which we originally discovered, and eribulin. The combination of CH5126766 and eribulin potently inhibited cell growth in the triple‐negative breast cancer cell lines tested. The underlying mechanism in the efficacy of this combination treatment in vitro and in vivo was due to enhanced apoptosis through the suppression of survivin and Bcl‐2 family proteins. We also showed the suppressed expression of programmed cell death ligand 1 (PD‐L1) in combination therapy in vivo. We found that combination therapy with eribulin and CH5126766 for triple‐negative breast cancer inhibited cell growth by apoptosis and raised a possibility that immune responses through suppression of PD‐L1 might partially contribute to inhibition of tumor growth, indicating the potential of this combination as a novel strategy for triple‐negative breast cancer.

Chemotherapy Options beyond the First Line in HER-Negative Metastatic Breast Cancer

Despite the recent advances in the biological understanding of breast cancer (BC), chemotherapy still represents a key component in the armamentarium for this disease. Different agents are available as mono-chemotherapy options in patients with locally advanced or metastatic BC (MBC) who progress after a first- and second-line treatment with anthracyclines and taxanes. However, no clear indication exists on what the best option is in some populations, such as heavily pretreated, elderly patients, triple-negative BC (TNBC), and those who do not respond to the first-line therapy. In this article, we summarize available literature evidence on different chemotherapy agents used beyond the first-line, in locally advanced or MBC patients, including rechallenge with anthracyclines and taxanes, antimetabolite and antimicrotubule agents, such as vinorelbine, capecitabine, eribulin, ixabepilone, and the newest developed agents, such as vinflunine, irinotecan, and etirinotecan.

Effect of renal function on neutrophil decreases following eribulin administration

BACKGROUND

Eribulin therapy has recently attracted attention from various viewpoints, including quality of life, and is considered a standard therapy for inoperable or recurrent breast cancer. Although a reduction in renal function reportedly decreases total eribulin clearance, its association with dose-limiting toxicity and the reduction of neutrophils remain unclear.

AIM

This study was aimed at analyzing the association between decreased renal function prior to eribulin administration and the occurrence of neutrophil reduction and time to treatment failure in patients with breast cancer.

METHODS AND RESULTS

We retrospectively assessed patients with breast cancer, who underwent eribulin therapy between July 2011 and March 2018. Multivariate analysis revealed creatinine clearance <70 mL/min and serum albumin levels <3.9 mg/dL as predictive factors for neutrophil reduction. Even on increasing the relative dose intensity by these factors, no difference in time to treatment failure was observed, suggesting that treatment efficacy is potentially unaffected.

CONCLUSIONS

For continuous eribulin therapy, eribulin may need to be administered to individual patients in accordance with renal function and albumin levels before treatment initiation.

Interim results of a real-world observational study of eribulin in soft tissue sarcoma including rare subtypes

Background

Although eribulin is used to treat soft tissue sarcomas (STSs), treatment data for rare subtypes are limited. We conducted a post-marketing surveillance study to assess safety and efficacy of eribulin in STS patients stratified by subtype.

Methods

Japanese patients (n = 256) with advanced or metastatic STS receiving eribulin treatment were monitored for treatment status, adverse events, diagnostic imaging, and clinical outcomes at 3 months and 1 year. Interim analysis was performed. Patients will be monitored up to 2 years.

Results

Interim analysis included 3-month (n = 255), imaging (n = 226), and 1-year (n = 105) data. STS subtype distribution was normal. Median number of eribulin cycles was 3.0 (range: 1–17 cycles). Among patients with imaging data, best overall tumor response (12 weeks) was partial response, 7.5% (n = 17); stable disease, 34.5% (n = 78); and stable disease ≥11 weeks, 10.2% (n = 23). Overall response rate (ORR), disease control rate (DCR), and clinical benefit rate (CBR) for all patients were 7.5%, 42.0% and 17.7%, respectively. ORR, DCR, and CBR were 10.3%, 32.0% and 16.5%, respectively, for patients with STS subtypes other than liposarcoma and leiomyosarcoma and included responses from patients with rare STS subtypes. Adverse drug reactions (ADRs) occurred in 211 (82.7%) patients (42 [16.5%] patients had serious ADRs), and none led to death. ADRs leading to drug withdrawal and dose reduction occurred in 27 (10.6%) and 55 (21.6%) patients, respectively.

Conclusion

Eribulin was generally well tolerated and showed antitumor activity against STSs, including rare subtypes that currently have few treatment options.

Clinical trial number

NCT03058406 (ClinicalTrials.gov)

Phase II Study of Eribulin Mesylate Administered Biweekly in Patients With Human Epidermal Growth Factor Receptor-2-negative Metastatic Breast Cancer

BACKGROUND

Patients with human epidermal growth factor receptor-2-negative metastatic breast cancer (MBC), whose disease progressed on prior chemotherapy, have a poor prognosis. Eribulin, a microtubule dynamics inhibitor, extends overall survival in previously treated MBC. The most common adverse event associated with eribulin is neutropenia, which may result in dose interruptions or reductions. A modified biweekly dosing schedule of eribulin was assessed for efficacy as well as improvements in hematologic toxicity.

PATIENTS AND METHODS

In this open-label, single-arm, multicenter, phase II study, previously treated (2-5 chemotherapy regimens for metastatic disease) patients with human epidermal growth factor receptor-2-negative MBC received intravenous eribulin 1.4 mg/m² over 2 to 5 minutes on days 1 and 15 of each 28-day cycle. The primary study endpoints were objective response rate (ORR; complete response [CR] + partial responses [PR]) and disease control rate (DCR; CR + PR + stable disease [SD]).

RESULTS

Among 58 treated patients, the ORR was 12% (95% confidence interval [CI], 5%-24%), DCR (CR, n = 1; PR, n = 6; SD, n = 30) was 65%, and the median progression-free survival was 3.6 months (95% CI, 2.9-4.1 months). Grade 3 or 4 neutropenia was 31%; 50% of all patients, and 78% of patients with neutropenia (all grades), received hematopoietic growth-factor support.

CONCLUSION

The efficacy and safety results obtained with a biweekly eribulin schedule in this phase II trial appear similar to those associated with the approved eribulin schedule (1.4 mg/m² on days 1 and 8 of a 21-day cycle) reported in the EMBRACE study.

Perspectives on the mechanism of action and clinical application of eribulin for metastatic breast cancer

Eribulin is a novel microtubule inhibitor with mitotic and nonmitotic mechanisms of action. Both pooled and subgroup analyses from large-scale Phase III clinical trials demonstrated that eribulin has substantial activity in patients with pretreated (anthracycline and a taxane) advanced or metastatic breast cancer. We review recent pharmacological and clinical findings pertaining to eribulin use in metastatic breast cancer – particularly highlighting eribulin in difficult-to-treat and aggressive disease, and safety data in specific patient populations. Additionally, recent advancements in our understanding of the mechanism of action of eribulin and potential future directions for its clinical development are discussed. Ongoing studies of eribulin in combination with immunotherapies and established cytotoxic agents may help shape the future landscape of breast cancer treatment.

Pharmacodynamic analysis of eribulin safety in breast cancer patients using real-world postmarketing surveillance data

Postmarketing surveillance is useful to collect safety data in real-world clinical settings. In this study, we applied postmarketing real-world data on a mechanistic model analysis for neutropenic profiles of eribulin in patients with recurrent or metastatic breast cancer. Demographic and safety data were collected using an active surveillance method from eribulin-treated recurrent or metastatic breast cancer patients. Changes in neutrophil counts over time were analyzed using a mechanistic pharmacodynamic model. Pathophysiological factors that might affect the severity of neutropenia were investigated, and neutropenic patterns were simulated for different treatment schedules. Clinical and laboratory data were collected from 401 patients (5199 neutrophil count measurements) who had not received granulocyte colony-stimulating factor and were eligible for pharmacodynamic analysis. The estimated mean parameters were as follows: mean transit time = 104.5 h, neutrophil proliferation rate constant = 0.0377 h-1 , neutrophil elimination rate constant = 0.0295 h-1 , and linear coefficient of drug effect = 0.0413 mL/ng. Low serum albumin levels and low baseline neutrophil counts were associated with severe neutropenia. The probability of grade ≥3 neutropenia was predicted to be 69%, 27%, and 27% for patients on standard, biweekly, and triweekly treatment scenarios, respectively, based on virtual simulations using the developed pharmacodynamic model. In conclusion, this is the first application of postmarketing surveillance data to a model-based safety analysis. This analysis of safety data reflecting authentic clinical settings will provide useful information on the safe use and potential risk factors of eribulin.

A phase II, multicenter, single-arm trial of eribulin as first- or second-line chemotherapy for HER2-negative advanced or metastatic breast cancer: evaluation of efficacy, safety, and patient-reported outcomes

PURPOSE

Although eribulin is a suitable option for early-line treatment of metastatic breast cancer (MBC), data on first- or second-line use of eribulin for human epidermal growth factor receptor 2 (HER2)-negative MBC are still limited. Therefore, we conducted a phase II trial to investigate the efficacy and safety of eribulin for first- or second-line chemotherapy for HER2-negative MBC.

MATERIALS AND METHODS

We performed a phase II, open-label, single-arm, multicenter study in Japan. Eligible patients were women with histologically confirmed HER2-negative MBC without chemotherapy or only one chemotherapy line for MBC. The primary endpoint was the overall response rate (ORR) and the secondary endpoints included the clinical benefit rate (ORR + stable disease for 6 months; CBR), progression-free survival (PFS), overall survival (OS), duration of response (DOR), safety, and health-related quality of life (HRQoL).

RESULTS

A total of 35 patients with HER2-negative MBC were enrolled between March 2013 and February 2017 (data cut-off July 31, 2017). The ORR was 37.1% (95% CI 21.1-53.2%). The CBR was 54.3% (95% CI 37.8-70.8%). The median PFS was 6.2 months (95% CI 2.7-9.4 months) and median OS was 21.4 months (95% CI 11.5-32.9 months). Common grade 3/4 adverse events were neutropenia (42.9%) but febrile neutropenia (2.9%). Although the majority of non-hematological adverse events were mild in severity, one patient died of pneumonitis. In HRQoL analysis, eribulin appeared to maintain HRQoL of many patients.

CONCLUSIONS

Eribulin as first- or second-line chemotherapy is effective and has manageable toxicity for patients with HER2-negative MBC.