Preliminary results of capecitabine metronomic chemotherapy in operable triple-negative breast cancer after standard adjuvant therapy – A single-arm phase II study

Metronomic Capecitabine Plus Aromatase Inhibitor as Initial Therapy in Patients With Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Metastatic Breast Cancer: The Phase III MECCA Trial

PURPOSE

The effects of metronomic chemotherapy plus endocrine therapy have yet to be elucidated through a randomized phase III clinical trial.

METHODS

Randomized clinical trials were conducted at 12 centers in China from August 22, 2017, to September 24, 2021, and the final follow-up date was August 25, 2023. Patients with hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC) who had no previous systemic therapy in the metastatic setting were enrolled. Participants were 1:1 assigned to receive either metronomic capecitabine plus an aromatase inhibitor (AI) or AI alone. The primary end point was progression-free survival (PFS). Secondary end points included overall survival (OS), objective response rate, disease control rate (defined as disease controlled for ≥24 weeks), and safety.

RESULTS

A total of 263 patients were randomly assigned, among which 254 patients formed the full analysis set. At the median follow-up time of 50.7 months, 203 PFS events occurred. The metronomic capecitabine plus AI arm exhibited a median PFS of 20.9 months compared with 11.9 months in the AI arm (hazard ratio [HR], 0.58 [95% CI, 0.43 to 0.76]). The median OS was not reached in the combination arm and was 45.1 months in the AI arm (HR, 0.58 [95% CI, 0.37 to 0.93]). The most common adverse events were palmar-plantar erythrodysesthesia and peripheral neuropathy; grade 3 events occurred in 15.1% of the patients receiving combination treatment.

CONCLUSION

The MECCA trial demonstrated a significant improvement in PFS and OS with first-line metronomic capecitabine plus AI compared with AI alone in patients with hormone receptor-positive+/HER2-negative MBC. Both treatment arms exhibited tolerable safety profiles consistent with previous reports.

Metronomic chemotherapy and breast cancer: a critical evaluation of its role in the new landscape of therapeutics

INTRODUCTION

Breast cancer (BC) remains a prevalent and challenging malignancy among women, with significant advancements in treatment strategies over the past decades. Traditional chemotherapy has been progressively supplemented by newer modalities, including Antibody-Drug Conjugates (ADCs), Immunotherapy (IO), and Targeted Therapies (TT). Despite these advancements, there remains a critical need for strategies that maintain efficacy while minimizing toxicity.

AREAS COVERED

This review delves into metronomic chemotherapy (MC), a novel approach involving the frequent administration of low-dose chemotherapy without prolonged breaks. We explore MC's impact across various breast cancer subtypes, such as Estrogen Receptor-Positive (ER+), HER2-Positive, and Triple-Negative Breast Cancer (TNBC). The literature reviewed highlights MC's mechanisms, including its anti-angiogenic, immunomodulatory, and antiproliferative effects, and its potential to improve treatment tolerability and address drug resistance.

EXPERT OPINION

MC represents a promising adjunct to existing therapies, particularly in advanced or resistant cases. Its unique dosing schedule could offer sustained antitumor activity with reduced toxicity, making it a viable option for long-term management. However, further research is warranted to establish optimal dosing regimens, identify predictive biomarkers, and delineate its role within combination treatment strategies. Clarifying these aspects could refine MC's application, potentially reshaping treatment paradigms and enhancing patient outcomes in breast cancer management.

Metronomic chemotherapy and drug repurposing: A paradigm shift in oncology

Cancer represents a significant global health and economic burden due to its high mortality rates. While effective in some instances, traditional chemotherapy often falls short of entirely eradicating various types of cancer. It can cause severe side effects due to harm to healthy cells. Two therapeutic approaches have risen to the forefront to address these limitations: metronomic chemotherapy (MCT) and drug repurposing. Metronomic chemotherapy is an innovative approach that breaks from traditional models. It involves the administration of chemotherapeutic regimens at lower doses, without long drug-free intervals that have previously been a hallmark of such treatments. This method offers a significant reduction in side effects and improved disease management. Simultaneously, drug repurposing has gained considerable attraction in cancer treatment. This approach involves utilizing existing drugs, initially developed for other therapeutic purposes, as potential cancer treatments. The application of known drugs in a new context accelerates the timeline from laboratory to patient due to pre-existing safety and dosage data. The intersection of these two strategies gives rise to a novel therapeutic approach named 'Metronomics.' This approach encapsulates the benefits of both MCT and drug repurposing, leading to reduced toxicity, potential for oral administration, improved patient quality of life, accelerated clinical implementation, and enhanced affordability. Numerous clinical studies have endorsed the efficacy of metronomic chemotherapy with tolerable side effects, underlining the potential of Metronomics in better cancer management, particularly in low- and middle-income countries. This review underscores the benefits and applications of metronomic chemotherapy and drug repurposing, specifically in the context of breast cancer, showcasing the promising results of pre-clinical and clinical studies. However, we acknowledge the necessity of additional clinical investigations to definitively establish the role of metronomic chemotherapy in conjunction with other treatments in comprehensive cancer management.

Nanoformulations-Based Metronomic Chemotherapy: Mechanism, Challenges, Recent Advances, and Future Perspectives

Cancer-related death is a significant health and economic burden worldwide, and some conventional chemotherapy is associated with limited effectiveness in completely curing various cancers, severe adverse effects, and destruction of healthy cells. To overcome the complications associated with conventional treatment, metronomic chemotherapy (MCT) is extensively suggested. In this review, we aim to highlight the importance of MCT over conventional chemotherapeutic approach with emphasis on nanoformulations-based MCT, their mechanism, challenges, recent advances, and future perspectives. Nanoformulations-based MCT revealed remarkable antitumor activity in both preclinical and clinical settings. For example, the metronomic scheduling of oxaliplatin-loaded nanoemulsion and polyethylene glycol-coated stealth nanoparticles incorporating paclitaxel were proven very effective in tumor-bearing mice and rats, respectively. Additionally, several clinical studies have demonstrated the benefit of MCT with acceptable tolerance. Moreover, metronomic might be a promising treatment strategy for improving cancer care in low- and middle-income nations. However, an appropriate alternative to a metronomic regimen for an individual ailment, suitable combinational delivery and scheduling, and predictive biomarkers are certain parts that remain unanswered. Further clinical-based comparative research studies are mandatory to be performed before entailing this treatment modality in clinical practice as alternative maintenance therapy or in place of transferring to therapeutic management.

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.

De-escalating cancer treatments during COVID 19 pandemic: Is metronomic chemotherapy a reasonable option?

COVID 19 pandemic represents an emergency for public health services and containment measures to reduce the risk of infection have been promptly activated worldwide. The healthcare systems reorganization has had a major impact on the management of cancer patients who are considered at high risk of infection. Recommendations and guidelines on how to manage cancer patients during COVID 19 pandemic have been published. Oral administration of chemotherapy is recommended to limit the access of cancer patients to hospital facilities and in some cases to guarantee the continuum of care. Low-dose metronomic administration of chemotherapy with different drugs and schedules has emerged in the last years as a possible alternative to conventional chemotherapy, due to its promising tumor control rates and excellent safety profiles. Moreover, given that many metronomic schedules use the oral route administration, it could represent a therapeutic strategy to ensure continuum of cancer care during COVID 19 pandemic. In this review we have selected all the clinical studies that have used the metronomic strategy, especially with oral drugs, in order to identify the subgroups of cancer patients who can benefit most from a metronomic approach even during COVID 19 pandemic.

Recent clinical evidence on metronomic dosing in controlled clinical trials: a systematic literature review

Introduction: Metronomic dosing is used to give continuous chemotherapy at low doses. The low doses have minimal side effects and may enable cancer treatment to be remodeled toward the management of chronic disease.Methods: We searched PubMed database to obtain relevant clinical trials studying metronomic chemotherapy (MCT). Our main focus was to find controlled phase II and phase III trials.Results: This systematic review summarizes the results of 91 clinical reports focusing on randomized phase II and phase III clinical studies between 2012 and 2018. During that time, nine randomized phase II and 10 randomized phase III studies were published. In the majority of the studies, MCT was well tolerated, and major side effects were rarely seen. Altogether, 4 phase III studies and 4 randomized phase II studies presented positive results and some clinical benefit.Discussion: Most of the studies did not show significantly improved overall survival or progression-free survival. Typically, the metronomic dosing was explored in a maintenance setup and was added to other agents given within normal high doses, whereas no trial was performed challenging metronomic dosing and best supportive care in later treatment lines. Therefore, there is no definite evidence on the efficacy of single metronomic dosing and firm evidence of metronomic dosing is still missing. There is a need for further confirmation of the usefulness of this approach in clinical practice.

Metronomic chemotherapy combined with endocrine therapy: are we challenging some dogmas?

INTRODUCTION

Metronomic chemotherapy exerts its effects via inhibition of angiogenesis, immune modulation of the tumoral stroma, induction of senescence and apoptosis of tumor cells. Due to its favorable toxicity profile and its oral administration, metronomic chemotherapy arises as a promising alternative to be combined with endocrine therapy for the treatment of patients with luminal breast cancer.

AREAS COVERED

The present manuscript reviews the rationale supporting the combination of metronomic chemotherapy and endocrine therapy, discussing the studies that evaluated this regimen in the treatment of early-stage and metastatic breast cancer patients. Finally, we conclude by providing an expert opinion on the current role and perspectives for the combination of metronomic chemotherapy and endocrine therapy in the management of patients with luminal breast cancer.

EXPERT OPINION

Retrospective series and early-phase clinical trials have shown promising signs of activity and a favorable toxicity profile with this regimen, which warrants further investigation as a treatment option for luminal breast cancer patients.

Metformin and propranolol combination prevents cancer progression and metastasis in different breast cancer models

Discovery of new drugs for cancer treatment is an expensive and time-consuming process and the percentage of drugs reaching the clinic remains quite low.

Drug repositioning refers to the identification and development of new uses for existing drugs and represents an alternative drug development strategy.

In this work, we evaluated the antitumor effect of metronomic treatment with a combination of two repositioned drugs, metformin and propranolol, in triple negative breast cancer models.

By in vitro studies with five different breast cancer derived cells, we observed that combined treatment decreased proliferation (P < 0.001), mitochondrial activity (P < 0.001), migration (P < 0.001) and invasion (P < 0.001). In vivo studies in immunocompetent mice confirmed the potential of this combination in reducing tumor growth (P < 0.001) and preventing metastasis (P < 0.05).

Taken together our results suggest that metformin plus propranolol combined treatment might be beneficial for triple negative breast cancer control, with no symptoms of toxicity.

Metronomic Chemotherapy in Triple-Negative Metastatic Breast Cancer: The Future Is Now?

Triple-negative breast cancer (TNBC) shows a very bad prognosis, even in early stages of disease. Metronomic chemotherapy 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. In the present article, we review preclinical and clinical data of metronomic administration of chemotherapy agents with or without biological agents in TNBC cell lines and patients, contextually reporting data from the VICTOR-2 study in the subgroup of patients with TNBC, in order to stimulate new ideas for the design of clinical trials in this subset of patients.

Metronomics in the neoadjuvant and adjuvant treatment of breast cancer

The concept of metronomic chemotherapy (MC) has evolved from a descriptive preclinical phenomenon encompassing inhibition of angiogenesis to a clinically validated treatment concept involving multiple potential mechanisms of action. Clinicians are progressively more incline to consider MC as a component of mainstream medical oncology practice in advanced breast cancer. However, more recently MC has been tested even in the adjuvant/neoadjuvant setting, taking the opportunity to obtain tumor specimens and blood samples, in order to identify tumor-specific or patient-specific biomarkers for personalizing treatments. In addition, the antiangiogenic and pro-immune nature of metronomic chemotherapy made triple negative breast cancer (TNBC) a good candidate for exploring low-dose maintenance treatment in the adjuvant setting or in combination with immunomodulatory drugs. The potential development of MC in breast cancer pass through the research to identify biomarkers and individual tumor characteristics that can better address the use of this treatment strategy in the future. Finally, the subjective attitude of patients represents one of the major factors that influence the choice and acceptance of a therapeutic program. Personal preference and considerations about quality of life should guide the treatment choice eventually prioritizing the use of MC. Nevertheless, more robust data from randomized phase III trials are needed in the future, in order to make clinicians more confident in using metronomic strategies.