Pan-European Expert Meeting on the Use of Metronomic Chemotherapy in Advanced Breast Cancer Patients: The PENELOPE Project

Metronomic Chemotherapy in Elderly Patients

PURPOSE OF REVIEW

This review describes the most relevant studies found in the scientific literature regarding metronomic chemotherapy (MCT) in the geriatric oncology population to support its use as a feasible treatment of care in the frail elderly patients.

RECENT FINDINGS

Recent years have seen a reevaluation of cancer chemotherapeutic drugs and MCT is an emerging schedule in phase II and III clinical trials. Ageing is one of the risk factors for the development of cancer, the incidence of whom increases dramatically in people who live longer. To date, standard oncological protocols involve chemotherapeutic drugs in short cycles of therapy at the maximum tolerated dose (MTD). Although these therapeutic regimens may be successful, they can cause important adverse drug reactions, especially in elderly or frail patients. MCT is a different modality of delivery of chemotherapeutic drugs (frequent low dose for prolonged time) and it looks at the overcoming of the limitations and disadvantages of MTD, in particular the toxicity aspect. We reviewed the experience of clinicians who have used MCT in clinical trials enrolling elderly patients with different cancer types.

Final results of the real-life observational VICTOR-6 study on metronomic chemotherapy in elderly metastatic breast cancer (MBC) patients

Nowadays, treatment of metastatic breast cancer (MBC) has been enriched with novel therapeutical strategies. Metronomic chemotherapy (mCHT) is a continuous and frequent administration of chemotherapy at a lower dose and so whit less toxicity. Thus, this strategy could be attractive for elderly MBC patients. Aim of this analysis is to provide insights into mCHT's activity in a real-life setting of elderly MBC patients. Data of patients ≥ 75 years old included in VICTOR-6 study were analyzed. VICTOR-6 is a multicentre, Italian, retrospective study, which collected data on mCHT in MBC patients treated between 2011 and 2016. A total of 112 patients were included. At the beginning of mCHT, median age was 81 years (75-98) and in 33% of the patients mCHT was the first line choice. Overall Response Rate (ORR) and Disease Control Rate (DCR) were 27.9% and 79.3%, respectively. Median PFS ranged between 7.6 and 9.1 months, OS between 14.1 and 18.5 months. The most relevant toxicity was the hematological one (24.1%); severe toxicity (grade 3-4) ranged from 0.9% for skin toxicity up to 8% for hematologic one. This is a large study about mCHT in elderly MBC patients, providing insights to be further investigated in this subgroup of frail patients.

Metronomic Chemo-Endocrine Therapy (FulVEC) as a Salvage Treatment for Patients with Advanced, Treatment-Refractory ER+/HER2-Breast Cancer-A Retrospective Analysis of Consecutive Patients Data

BACKGROUND

Breast cancer, with 2.3 million new cases and 0.7 million deaths every year, represents a great medical challenge worldwide. These numbers confirm that approx. 30% of BC patients will develop an incurable disease requiring life-long, palliative systemic treatment. Endocrine treatment and chemotherapy administered in a sequential fashion are the basic treatment options in advanced ER+/HER2- BC, which is the most common BC type. The palliative, long-term treatment of advanced BC should not only be highly active but also minimally toxic to allow long-term survival with the optimal quality of life. A combination of metronomic chemotherapy (MC) with endocrine treatment (ET) in patients who failed earlier lines of ET represents an interesting and promising option.

METHODS

The methodology includes retrospective data analyses of pretreated, metastatic ER+/HER2- BC (mBC) patients who were treated with the FulVEC regimen combining fulvestrant and MC (cyclophosphamide, vinorelbine, and capecitabine).

RESULTS

Thirty-nine previously treated (median 2 lines 1-9) mBC patients received FulVEC. The median PFS and OS were 8.4 and 21.5 months, respectively. Biochemical responses (CA-15.3 serum marker decline ≥50%) were observed in 48.7%, and any increase in CA-15.3 was observed in 23.1% of patients. The activity of FulVEC was independent of previous treatments with fulvestrant of cytotoxic components of the FulVEC regimen. The treatment was safe and well tolerated.

CONCLUSIONS

Metronomic chemo-endocrine therapy with FulVEC regimen represents an interesting option and compares favorably with other approaches in patients' refractory to endocrine treatments. A phase II randomized trial is warranted.

Metronomic Chemotherapy Based on Topotecan or Topotecan and Cyclophosphamide Combination (CyTo) in Advanced, Pretreated Ovarian Cancer

Patients with advanced ovarian cancer (OC) have a detrimental prognosis. The options for systemic treatment of advanced OC in later lines of treatment are limited by the availability of active therapies and their applicability to often fragile, exhausted patients with poor performance status. Metronomic chemotherapy (MC) is a concept of a continuous administration of cytotoxic drugs, which is characterized by multidirectional activity (anti-proliferative, anti-angiogenic, and anti-immunosuppressive) and low toxicity. We have performed a retrospective analysis of consecutive, advanced, chemo-refractory OC patients treated with MC based on single-agent topotecan (1 mg p.o. q2d) or on a topotecan (1 mg q2d) and cyclophosphamide (50 mg p.o. qd) combination (CyTo). Metronomic chemotherapy demonstrated promising activity, with 72% and 86% of patients achieving biochemical or objective disease control and 18% and 27% of patients achieving a biochemical or objective response, respectively. The median PFS in the whole population was 3.65 months, but the median PFS in patients with a biochemical response to MC (18.2% of patients) reached 10.7 months. The study also suggested that overweight or obese patients had significantly better outcomes on MC than patients with BMI <25 kg/m². This article is the first report in the literature on metronomic chemotherapy based on a topotecan + cyclophosphamide combination (CyTo). The CyTo regimen demonstrated safety, clinical activity, and potential broad clinical applicability in advanced OC patients and will be evaluated in a forthcoming clinical trial.

Metronomic Chemotherapy for Metastatic Breast Cancer Treatment: Clinical and Preclinical Data between Lights and Shadows

Metronomic chemotherapy (mCHT), defined as continuous administration of low-dose chemotherapeutic agents with no or short regular treatment-free intervals, was first introduced to the clinic in international guidelines in 2017, and, since then, has become one of the available strategies for the treatment of advanced breast cancer (ABC). Despite recent successes, many unsolved practical and theoretical issues remain to be addressed. The present review aims to identify the “lights and shadows” of mCHT in preclinical and clinical settings. In the preclinical setting, several findings indicate that one of the most noticeable effects of mCHT is on the tumor microenvironment, which, over the last twenty years, has been demonstrated to be pivotal in supporting tumor cell survival and proliferation. On the other hand, the direct effects on tumor cells have been less well-defined. In addition, critical items to be addressed are the lack of definition of an optimal biological dose (OBD), the method of administration of metronomic schedules, and the recognition and validation of predictive biomarkers. In the clinical context—where mCHT has mainly been used in a metastatic setting—low toxicity is the most well-recognised light of mCHT, whereas the type of study design, the absence of randomised trials and uncertainty in terms of doses and drugs remain among the shadows. In conclusion, growing evidence indicates that mCHT is a suitable treatment option for selected metastatic breast cancer (MBC) patients. Moreover, given its multimodal mechanisms of action, its addition to immunological and targeted therapies might represent a promising new approach to the treatment of MBC. More preclinical data are needed in this regard, which can only be obtained through support for translational research as the key link between basic science and patient care.

Metronomic Chemotherapy in Prostate Cancer

Despite the significant expansion of the therapeutic armamentarium associated with the introduction of novel endocrine therapies, cytotoxic agents, radiopharmaceuticals, and PARP inhibitors, progression of metastatic castration-resistant prostate cancer (mCRPC) beyond treatment options remains the leading cause of death in advanced prostate cancer patients. Metronomic chemotherapy (MC) is an old concept of wise utilization of cytotoxic agents administered continuously and at low doses. The metronomic is unique due to its multidimensional mechanisms of action involving: (i) inhibition of cancer cell proliferation, (ii) inhibition of angiogenesis, (iii) mitigation of tumor-related immunosuppression, (iv) impairment of cancer stem cell functions, and (v) modulation of tumor and host microbiome. MC has been extensively studied in advanced prostate cancer before the advent of novel therapies, and its actual activity in contemporary, heavily pretreated mCRPC patients is unknown. We have conducted a prospective analysis of consecutive cases of mCRPC patients who failed all available standard therapies to find the optimal MC regimen for phase II studies. The metronomic combination of weekly paclitaxel 60 mg/m² i.v. with capecitabine 1500 mg/d p.o. and cyclophosphamide 50 mg/d p.o. was selected as the preferred regimen for a planned phase II study in heavily pretreated mCRPC patients.

Enhanced Paclitaxel Efficacy to Suppress Triple-Negative Breast Cancer Progression Using Metronomic Chemotherapy with a Controlled Release System of Electrospun Poly-d-l-Lactide-Co-Glycolide (PLGA) Nanofibers

Simple Summary

Treatment of metastatic triple-negative breast cancer (TNBC) relies on chemotherapy. To improve the efficacy of chemotherapy and avoid systemic toxicity, metronomic chemotherapy using continuous administration of low-dose chemotherapy could be a solution. The paclitaxel-loaded PLGA nanofibers allow for continuous and prolonged drug release, which is compatible with the concept of metronomic chemotherapy. The animal study revealed that the strategy successfully inhibited the growth of the primary tumor and distant metastasis without sarcopenia. These data offer new insights into the role of drug-loaded nanofibers in the treatment of metastatic TNBC.

Abstract

Triple-negative breast cancer (TNBC) is highly aggressive and responds poorly to conventional chemotherapy. The challenge of TNBC therapy is to maximize the efficacies of conventional chemotherapeutic agents and reduce their toxicities. Metronomic chemotherapy using continuous low-dose chemotherapy has been proposed as a new treatment option, but this approach is limited by the selection of drugs. To improve antitumor therapeutic effects, we developed electrospun paclitaxel-loaded poly-d-l-lactide-co-glycolide (PLGA) nanofibers as a topical implantable delivery device for controlled drug release and site-specific treatment. The subcutaneously implanted paclitaxel-loaded nanofibrous membrane in mice was compatible with the concept of metronomic chemotherapy; it significantly enhanced antitumor activity, inhibited local tumor growth, constrained distant metastasis, and prolonged survival compared with intraperitoneal paclitaxel injection. Furthermore, under paclitaxel-loaded nanofiber treatment, systemic toxicity was low with a persistent increase in lean body weight in mice; in contrast, body weight decreased in other groups. The paclitaxel-loaded nanofibrous membranes provided sustained drug release and site-specific treatment by directly targeting and changing the tumor microenvironment, resulting in low systemic toxicity and a significant improvement in the therapeutic effect and safety compared with conventional chemotherapy. Thus, metronomic chemotherapy with paclitaxel-loaded nanofibrous membranes offers a promising strategy for the treatment of TNBC.

Metronomic Chemotherapy

Simple Summary

The present article reviews the state of the art of metronomic chemotherapy use to treat the principal types of cancers, namely breast, non-small cell lung cancer and colorectal ones, and of the most recent progresses in understanding the underlying mechanisms of action. Areas of novelty, in terms of new regimens, new types of cancer suitable for Metronomic chemotherapy (mCHT) and the overview of current ongoing trials, along with a critical review of them, are also provided.

Abstract

Metronomic chemotherapy treatment (mCHT) refers to the chronic administration of low doses chemotherapy that can sustain prolonged, and active plasma levels of drugs, producing favorable tolerability and it is a new promising therapeutic approach in solid and in hematologic tumors. mCHT has not only a direct effect on tumor cells, but also an action on cell microenvironment, by inhibiting tumor angiogenesis, or promoting immune response and for these reasons can be considered a multi-target therapy itself. Here we review the state of the art of mCHT use in some classical tumour types, such as breast and no small cell lung cancer (NSCLC), see what is new regarding most recent data in different cancer types, such as glioblastoma (GBL) and acute myeloid leukemia (AML), and new drugs with potential metronomic administration. Finally, a look at the strategic use of mCHT in the context of health emergencies, or in low –and middle-income countries (LMICs), where access to adequate healthcare is often not easy, is mandatory, as we always need to bear in in mind that equity in care must be a compulsory part of our medical work and research.

Phase II study of metronomic treatment with daily oral vinorelbine as first-line chemotherapy in patients with advanced/metastatic HR+/HER2- breast cancer resistant to endocrine therapy: VinoMetro-AGO-B-046

Purpose

Metronomic chemotherapy (MCT) is an increasingly used treatment option in hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2−) advanced/metastatic breast cancer (MBC) after failure of endocrine-based therapies.

Methods

VinoMetro was a multicentre, open-label, single-arm, phase II study of metronomic oral vinorelbine (VRL; 30 mg/day) as a first-line chemotherapy (CT) in patients with HR+/HER2− MBC after endocrine failure. The primary endpoint was the clinical benefit rate (CBR) at 24 weeks.

Results

Between January 2017 and April 2019, nine patients were enrolled. The CBR was 22.2% (90% confidence interval [CI] 4.1–55.0), p = 0.211. The median progression-free survival (PFS) was 12.0 weeks (95% CI 11.3–12.7). Grade 3–4 adverse events (AEs) occurred in 22.2% of patients. One patient died of febrile neutropenia.

Conclusion

VinoMetro (AGO-B-046) was closed early after nine patients and occurrence of one grade 5 toxicity in agreement with the lead institutional review board (IRB). Metronomic dosing of oral VRL in HR+/HER2− MBC as first-line CT after failure of endocrine therapies showed only limited benefit in this population.

Trial registration number and date of registration

ClinicalTrials.gov Identifier: NCT03007992; December 15, 2016.

Metronomic therapy in advanced breast cancer and NSCLC: vinorelbine as a paradigm of recent progress

INTRODUCTION

Metronomic chemotherapy (MCT) is based on frequent dosing of the drug. . This leads to pharmacologically active but low plasma concentrations that reduce toxicity. MCT seems to work primarily via indirect effects on tumor cells and their microenvironment, rather than direct antitumor effects. Oral vinorelbine is one of the most widely studied MCT approaches in both advanced breast cancer and non-small cell lung cancer.

EXPERT OPINION

MCT with vinorelbine has proven efficacy, tolerability and quality of life benefits both as monotherapy and in combination with other MCTs or targeted agents, in first-line therapy and in previously treated patients. Key populations are emerging who may be particularly well suited to metronomic vinorelbine, including those with indolent disease, older individuals, and those with multiple comorbidities and/or bone metastases. Ongoing trials should help to further delineate these target groups. Additional work is needed to better understand the optimal vinorelbine regimen, particularly when used in combination or in non-Caucasian patients. Markers are also required to help identify individuals who are most likely to respond. Nonetheless, the efficacy and tolerability of MCT, allied to improved patient convenience, reduced need for medical engagement and lower cost, make it an appealing option - particular in resource-constrained healthcare environments.

Active metronomic vinorelbine schedules decrease plasma interleukin-2 levels in mice with Lewis lung carcinoma

The aim of our study was to investigate the effects of metronomic vinorelbine (mVNR) in a tumor model of Lewis Lung (LL) cancer in immunocompetent C57BL/6 mice, looking at the plasma levels of interleukin-2 (IL-2) and interleukin-8 (IL-8). mVNR caused a concentration-dependent antiproliferative effect in vitro on LL/2 cells. The in vivo experiment showed the significant antitumor effects of mVNR at the dose of 4 mg/Kg and 5 mg/Kg, 3 times/week, and the significant dose-dependent decrease of IL-2 concentrations in plasma samples. Conversely, such an effect was not observed for IL-8. A significant decrease in microvessel density was also found at both the active mVNR doses. In conclusion, our study confirmed the activity of mVNR in an immunocompetent model of lung carcinoma and suggest multiple mechanisms of action, including the modulation of IL-2 levels.

Immunostimulatory and anti-tumor metronomic cyclophosphamide regimens assessed in primary orthotopic and metastatic murine breast cancer

The impressive successes of immune checkpoint blockade antibodies to treat various types of cancer are limited to minor subsets of patients. Combination therapy strategies, including with chemotherapy, are being explored to possibly improve the efficacy of immunotherapies. Here we report results regarding the use of an immunostimulatory regimen of metronomic cyclophosphamide (CTX). We show that in orthotopic models of syngeneic murine triple-negative breast cancer (EMT6), CTX administered at 140 mg/kg every 6 days (CTX140 1q6d) is superior at inhibiting primary tumor growth when compared to maximum tolerated dose or daily oral (continuous) low-dose CTX. In SCID or SCID beige mice, anti-tumor effects of CTX140 1q6d are reduced, reinforcing the therapeutic contribution of the adaptive and innate immune systems. In a second breast cancer model (SP1-AC2M2), CTX140 1q6d again showed clear superiority in anti-tumor effects, causing complete tumor regressions; however, these mice were not protected from subsequent tumor re-challenge, suggesting absence of immune memory. We also show that in an aggressive and metastatic cisplatin-resistant variant (EMT6-CDDP), CTX140 1q6d is superior and invokes an influx of intra-tumoral CD4+ and CD8+ T cells. CTX increases expression of tumor cell PD-L1; however, when combined with concomitant PD-L1 antibody therapy none of the CTX regimens showed increased benefit. This work sheds light on the potential use of metronomic CTX for the treatment of breast cancer, in particular using the quasi-weekly regimen, but also underscores the complexity of the anti-tumor mechanisms and potential to improve immune checkpoint therapy efficacy.

Low-dose metronomic chemotherapy as an efficient treatment option in metastatic breast cancer-results of an exploratory case-control study

Purpose

There is growing interest in low-dose metronomic chemotherapy (LDMC) in metastatic breast cancer (MBC). In this retrospective case–control analysis, we compared the efficacy of LDMC and conventional chemotherapy (CCT) in MBC.

Methods

Each LDMC patient receiving oral cyclophosphamide (CTX) (50 mg daily) and methotrexate (MTX) (2.5 mg every other day) was matched with two controls who received CCT. Age, number of chemotherapy lines and metastatic sites as well as hormone receptor (HR) status were considered as matching criteria. Primary endpoint was disease control rate longer than 24 weeks (DCR). Secondary endpoints were progression-free survival (PFS), duration of response (DoR) and subgroup analyses using the matching criteria.

Results

40 cases and 80 controls entered the study. 30.0% patients with LDMC and 22.5% patients with CCT showed DCR (p = 0.380). The median PFS was 12.0 weeks in both groups (p = 0.218) and the median DoR was 31.0 vs. 20.5 weeks (p = 0.383), respectively. Among younger patients, DCR was 40.0% in LDMC vs. 25.0% in the CCT group (p = 0.249). DCR was achieved in 33.3% vs. 26.2% non-heavily pretreated patients (p = 0.568) and in 36.0% vs. 18.0% patients without multiple metastases (p = 0.096), respectively. In the HR-positive group, 30.0% LDMC vs. 28.3% CCT patients showed DCR (p = 1.000). Among triple-negative patients, DCR was achieved in 30.0% LDMC and 5.0% CCT patients (p = 0.095).

Conclusions

We demonstrated a similar efficacy of LDMC compared to CCT in the treatment of MBC. Thus, LDMC may be a valuable treatment option in selected MBC patients.

Metronomic chemotherapy of cyclophosphamide plus methotrexate for advanced breast cancer: Real-world data analyses and experience of one center

Background

Real‐world data of the CM regimen [cyclophosphamide (CTX) plus methotrexate (MTX)] in metronomic pattern for advanced breast cancer is limited to small‐sample or retrospective studies. This study was aimed to determine the effectiveness and safety of CM regimen in treating advanced breast cancer and to identify which patients are most likely to benefit from metronomic CM regimen.

Methods

Patients with advanced breast cancer who received the metronomic CM regimen at least once between January 2009 and February 2019 in Sun Yat‐sen University Cancer Center were included. Clinicopathological characteristics were collected. Overall survival (OS) and progression‐free survival (PFS) were assessed using Kaplan‐Meier estimates. Characteristics between patients with PFS < 6 months and ≥6 months were compared using the Chi‐square test. Univariate and multivariate Cox regression model was used to estimate the prognostic factors for PFS and OS.

Results

A total of 186 patients were included. The median age and follow‐up were 49 years and 13.3 months, respectively. Over 50% of the patients were estrogen receptor/progesterone receptor‐positive, and 60.8% had been heavily treated (≥3 lines). The objective response rate was 3.8%, the disease control rate at 12 weeks was 41.4%, and the clinical benefit rate at 24 weeks was 31.2% (58/186). The median PFS was 4.0 months [95% confidence interval (CI): 3.6‐4.7 months], the median duration of clinical benefit was 9.5 months (95% CI: 8.2‐10.8 months), and the median OS was 26.8 months (95% CI: 20.9‐37.7 months). Multivariate analysis for PFS revealed the CM regimen as maintenance therapy and no liver metastasis as favorable prognostic factors. Furthermore, patients without liver metastasis were more likely to have a PFS over 6 months than those with liver involvement (P = 0.022). Liver, lymph node, and brain metastases were unfavorable prognostic factors for OS. The CM regimen was well‐tolerated without newly reported adverse events.

Conclusions

The CM regimen was effective in selected patients. In clinical practice, it would be better used as maintenance therapy and in patients without liver metastasis. Further follow‐up investigation should be performed to examine its effect when used in combination with other treatments and determine predictive biomarkers.

Comparison of Model-Free and Model-Based Dynamic Contrast-Enhanced Magnetic Resonance Imaging Pharmacokinetic Parameters for Predicting Breast Cancers' Response to Neoadjuvant Chemotherapy

OBJECTIVE

To prospectively compare the performance of model-based and model-free dynamic contrast-enhanced (DCE) pharmacokinetic parameters in monitoring breast cancers' early response to neoadjuvant chemotherapy (NACT).

METHODS

Sixty patients, with 61 pathology-proven breast cancers, were examined using DCE magnetic resonance imaging before, after the first cycle, and after full cycles of NACT. Both model-based (Ktrans and others) and model-free parameters, mainly time-intensity curve (TIC), were measured. According to Miller-Payne grading, patients were divided into response and nonresponse group. Mann-Whitney U test, Fisher exact test, multivariate logistic regression, and receiver operating characteristic curve were used in analysis.

RESULTS

After the first cycle, among all the parameters, Ktrans and TIC were strongly associated with tumors' early response. There was no significant difference between the areas under receiver operating characteristic curve of Ktrans and TIC (0.768, 0.852, respectively).

CONCLUSIONS

Model-based and model-free DCE parameters, especially Ktrans and TIC, have similar performance in predicting the efficacy of NACT for breast cancers.

Metronomic chemotherapy for advanced breast cancer patients in the real world practice: Final results of the VICTOR-6 study

Metronomic chemotherapy (mCHT) refers to the minimum biologically effective dose of a chemotherapy agent given as a continuous dosing regimen, with no prolonged drug-free breaks, that leads to antitumor activity. Aim of the present study is to describe the use of mCHT in a retrospective cohort of metastatic breast cancer (MBC) patients in order to collect data regarding the different types and regimens of drugs employed, their efficacy and safety. Between January 2011 and December 2016, data of 584 metastatic breast cancer patients treated with mCHT were collected. The use of VRL-based regimens increased during the time of observation (2011: 16.8% - 2016: 29.8%), as well as CTX-based ones (2011: 17.1% - 2016: 25.6%), whereas CAPE-based and MTX-based regimens remained stable. In the 1st-line setting, the highest ORR and DCR were observed for VRL-based regimens (single agent: 44% and 88%; combination: 36.7% and 82.4%, respectively). Assuming VRL-single agent as the referee treatment (median PFS: 7.2 months, 95% CI: 5.3-10.3), the longest median PFS were observed in VRL-combination regimens (9.5, 95%CI 88.8-11.3, HR = 0.72) and in CAPE-single agent (10.7, 95%CI 8.3-15.8, HR = 0.70). The VICTOR-6 study provides new data coming from the real-life setting, by adding new information regarding the use of mCHT as an option of treatment for MBC patients.