The potential clinical promise of 'multimodality' metronomic chemotherapy revealed by preclinical studies of metastatic disease

Targeting the tumour vasculature: from vessel destruction to promotion

As angiogenesis was recognized as a core hallmark of cancer growth and survival, several strategies have been implemented to target the tumour vasculature. Yet to date, attempts have rarely been so diverse, ranging from vessel growth inhibition and destruction to vessel normalization, reprogramming and vessel growth promotion. Some of these strategies, combined with standard of care, have translated into improved cancer therapies, but their successes are constrained to certain cancer types. This Review provides an overview of these vascular targeting approaches and puts them into context based on our subsequent improved understanding of the tumour vasculature as an integral part of the tumour microenvironment with which it is functionally interlinked. This new knowledge has already led to dual targeting of the vascular and immune cell compartments and sets the scene for future investigations of possible alternative approaches that consider the vascular link with other tumour microenvironment components for improved cancer therapy.

Blood Vessel-Targeted Therapy in Colorectal Cancer: Current Strategies and Future Perspectives

The vasculature is a key player and regulatory component in the multicellular microenvironment of solid tumors and, consequently, a therapeutic target. In colorectal carcinoma (CRC), antiangiogenic treatment was approved almost 20 years ago, but there are still no valid predictors of response. In addition, treatment resistance has become a problem. Vascular heterogeneity and plasticity due to species-, organ-, and milieu-dependent phenotypic and functional differences of blood vascular cells reduced the hope of being able to apply a standard approach of antiangiogenic therapy to all patients. In addition, the pathological vasculature in CRC is characterized by heterogeneous perfusion, impaired barrier function, immunosuppressive endothelial cell anergy, and metabolic competition-induced microenvironmental stress. Only recently, angiocrine proteins have been identified that are specifically released from vascular cells and can regulate tumor initiation and progression in an autocrine and paracrine manner. In this review, we summarize the history and current strategies for applying antiangiogenic treatment and discuss the associated challenges and opportunities, including normalizing the tumor vasculature, modulating milieu-dependent vascular heterogeneity, and targeting functions of angiocrine proteins. These new strategies could open perspectives for future vascular-targeted and patient-tailored therapy selection in CRC.

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.

Low-dose metronomic cisplatin as an antiangiogenic and anti-inflammatory strategy for cancer

BACKGROUND

Conventional chemotherapy is based on the maximum tolerated dose (MTD) and requires treatment-free intervals to restore normal host cells. MTD chemotherapy may induce angiogenesis or immunosuppressive cell infiltration during treatment-free intervals. Low-dose metronomic (LDM) chemotherapy is defined as frequent administration at lower doses and causes less inflammatory change, whereas MTD chemotherapy induces an inflammatory change. Although several LDM regimens have been applied, LDM cisplatin (CDDP) has been rarely reported. This study addressed the efficacy of LDM CDDP on tumour endothelial cell phenotypic alteration compared to MTD CDDP.

METHODS

Tumour growth and metastasis were assessed in bladder cancer-bearing mice treated with LDM or MTD gemcitabine (GEM) and CDDP. To elucidate the therapeutic effects of LDM CDDP, the change of tumour vasculature, tumour-infiltrating immune cells and inflammatory changes were evaluated by histological analysis and mRNA expression in tumour tissues.

RESULTS

Tumour growth and bone metastasis were more suppressed by LDM CDDP + MTD GEM treatment than MTD CDDP + MTD GEM. Myeloid-derived suppressor cell accumulation was reduced by LDM CDDP, whereas inflammatory change was induced in the tumour microenvironment by MTD CDDP.

CONCLUSION

LDM CDDP does not cause inflammatory change unlike MTD CDDP, suggesting that it is a promising strategy in chemotherapy.

Therapeutic targeting of angiopoietins in tumor angiogenesis and cancer development

The formation and progression of tumors in humans are linked to the abnormal development of new blood vessels known as neo-angiogenesis. Angiogenesis is a broad word that encompasses endothelial cell migration, proliferation, tube formation, and intussusception, as well as peri-EC recruitment and extracellular matrix formation. Tumor angiogenesis is regulated by angiogenic factors, out of which some of the most potent angiogenic factors such as vascular endothelial growth factor and Angiopoietins (ANGs) in the body are produced by macrophages and other immune cells within the tumor microenvironment. ANGs have a distinct function in tumor angiogenesis and behavior. ANG1, ANG 2, ANG 3, and ANG 4 are the family members of ANG out of which ANG2 has been extensively investigated owing to its unique role in modifying angiogenesis and its tight association with tumor progression, growth, and invasion/metastasis, which makes it an excellent candidate for therapeutic intervention in human malignancies. ANG modulators have demonstrated encouraging outcomes in the treatment of tumor development, either alone or in conjunction with VEGF inhibitors. Future development of more ANG modulators targeting other ANGs is needed. The implication of ANG1, ANG3, and ANG4 as probable therapeutic targets for anti-angiogenesis treatment in tumor development should be also evaluated. The article has described the role of ANG in tumor angiogenesis as well as tumor growth and the treatment strategies modulating ANGs in tumor angiogenesis as demonstrated in clinical studies. The pharmacological modulation of ANGs and ANG-regulated pathways that are responsible for tumor angiogenesis and cancer development should be evaluated for the development of future molecular therapies.

Metronomic Administration of Topotecan Alone and in Combination with Docetaxel Inhibits Epithelial-mesenchymal Transition in Aggressive Variant Prostate Cancers

Prostate cancer is the second leading cause of noncutaneous cancer-related deaths in American men. Androgen deprivation therapy (ADT), radical prostatectomy, and radiotherapy remain the primary treatment for patients with early-stage prostate cancer (castration-sensitive prostate cancer). Following ADT, many patients ultimately develop metastatic castration-resistant prostate cancer (mCRPC). Standard chemotherapy options for CRPC are docetaxel (DTX) and cabazitaxel, which increase median survival, although the development of resistance is common. Cancer stem-like cells possess mesenchymal phenotypes [epithelial-to-mesenchymal transition (EMT)] and play crucial roles in tumor initiation and progression of mCRPC. We have shown that low-dose continuous administration of topotecan (METRO-TOPO) inhibits prostate cancer growth by interfering with key cancer pathway genes. This study utilized bulk and single-cell or whole-transcriptome analysis [(RNA sequencing (RNA-seq) and single-cell RNA sequencing (scRNA-seq)], and we observed greater expression of several EMT markers, including Vimentin, hyaluronan synthase-3, S100 calcium binding protein A6, TGFB1, CD44, CD55, and CD109 in European American and African American aggressive variant prostate cancer (AVPC) subtypes-mCRPC, neuroendocrine variant (NEPC), and taxane-resistant. The taxane-resistant gene FSCN1 was also expressed highly in single-cell subclonal populations in mCRPC. Furthermore, metronomic-topotecan single agent and combinations with DTX downregulated these EMT markers as well as CD44+ and CD44+/CD133+ "stem-like" cell populations. A microfluidic chip-based cell invasion assay revealed that METRO-TOPO treatment as a single agent or in combination with DTX was potentially effective against invasive prostate cancer spread. Our RNA-seq and scRNA-seq analysis were supported by in silico and in vitro studies, suggesting METRO-TOPO combined with DTX may inhibit oncogenic progression by reducing cancer stemness in AVPC through the inhibition of EMT markers and multiple oncogenic factors/pathways.

Significance

The utilization of metronomic-like dosing regimens of topotecan alone and in combination with DTX resulted in the suppression of makers associated with EMT and stem-like cell populations in AVPC models. The identification of molecular signatures and their potential to serve as novel biomarkers for monitoring treatment efficacy and disease progression response to treatment efficacy and disease progression were achieved using bulk RNA-seq and single-cell-omics methodologies.

Computational simulations of tumor growth and treatment response: Benefits of high-frequency, low-dose drug regimens and concurrent vascular normalization

Implementation of effective cancer treatment strategies requires consideration of how the spatiotemporal heterogeneities within the tumor microenvironment (TME) influence tumor progression and treatment response. Here, we developed a multi-scale three-dimensional mathematical model of the TME to simulate tumor growth and angiogenesis and then employed the model to evaluate an array of single and combination therapy approaches. Treatments included maximum tolerated dose or metronomic (i.e., frequent low doses) scheduling of anti-cancer drugs combined with anti-angiogenic therapy. The results show that metronomic therapy normalizes the tumor vasculature to improve drug delivery, modulates cancer metabolism, decreases interstitial fluid pressure and decreases cancer cell invasion. Further, we find that combining an anti-cancer drug with anti-angiogenic treatment enhances tumor killing and reduces drug accumulation in normal tissues. We also show that combined anti-angiogenic and anti-cancer drugs can decrease cancer invasiveness and normalize the cancer metabolic microenvironment leading to reduced hypoxia and hypoglycemia. Our model simulations suggest that vessel normalization combined with metronomic cytotoxic therapy has beneficial effects by enhancing tumor killing and limiting normal tissue toxicity.

Metronomic capecitabine inhibits liver transplant rejection in rats by triggering recipients’ T cell ferroptosis

BACKGROUND

Capecitabine (CAP) is a classic antimetabolic drug and has shown potential antirejection effects after liver transplantation (LT) in clinical studies. Our previous study showed that metronomic CAP can cause the programmed death of T cells by inducing oxidative stress in healthy mice. Ferroptosis, a newly defined non-apoptotic cell death that occurs in response to iron overload and lethal levels of lipid peroxidation, is an important mechanism by which CAP induces cell death. Therefore, ferroptosis may also play an important role in CAP-induced T cell death and play an immunosuppressive role in acute rejection after trans-plantation.

AIM

To investigate the functions and underlying mechanisms of antirejection effects of metronomic CAP.

METHODS

A rat LT model of acute rejection was established, and the effect of metronomic CAP on splenic hematopoietic function and acute graft rejection was evaluated 7 d after LT. In vitro, primary CD3⁺ T cells were sorted from rat spleens and human peripheral blood, and co-cultured with or without 5-fluorouracil (5-FU) (active agent of CAP). The levels of ferroptosis-related proteins, ferrous ion concentration, and oxidative stress-related indicators were observed. The changes in mito-chondrial structure were observed using electron microscopy.

RESULTS

With no significant myelotoxicity, metronomic CAP alleviated graft injury (Banff score 9 vs 7.333, P < 0.001), prolonged the survival time of the recipient rats (11.5 d vs 16 d, P < 0.01), and reduced the infiltration rate of CD3⁺ T cells in peripheral blood (6.859 vs 3.735, P < 0.001), liver graft (7.459 vs 3.432, P < 0.001), and spleen (26.92 vs 12.9, P < 0.001), thereby inhibiting acute rejection after LT. In vitro, 5-FU, an end product of CAP metabolism, induced the degradation of the ferritin heavy chain by upregulating nuclear receptor coactivator 4, which caused the accumulation of ferrous ions. It also inhibited nuclear erythroid 2 p45-related factor 2, heme oxygenase-1, and glutathione peroxidase 4, eventually leading to oxidative damage and ferroptosis of T cells.

CONCLUSION

Metronomic CAP can suppress acute allograft rejection in rats by triggering CD3⁺ T cell ferroptosis, which makes it an effective immunosuppressive agent after LT.

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.

Normalizing tumor microenvironment with nanomedicine and metronomic therapy to improve immunotherapy

Nanomedicine offered hope for improving the treatment of cancer but the survival benefits of the clinically approved nanomedicines are modest in many cases when compared to conventional chemotherapy. Metronomic therapy, defined as the frequent, low dose administration of chemotherapeutics – is being tested in clinical trials as an alternative to the conventional maximum tolerated dose (MTD) chemotherapy schedule. Although metronomic chemotherapy has not been clinically approved yet, it has shown better survival than MTD in many preclinical studies. When beneficial, metronomic therapy seems to be associated with normalization of the tumor microenvironment including improvements in tumor perfusion, tissue oxygenation and drug delivery as well as activation of the immune system. Recent preclinical studies suggest that nanomedicines can cause similar changes in the tumor microenvironment. Here, by employing a mathematical framework, we show that both approaches can serve as normalization strategies to enhance treatment. Furthermore, employing murine breast and fibrosarcoma tumor models as well as ultrasound shear wave elastography and contrast-enhanced ultrasound, we provide evidence that the approved nanomedicine Doxil can induce normalization in a dose-dependent manner by improving tumor perfusion as a result of tissue softening. Finally, we show that pretreatment with a normalizing dose of Doxil can improve the efficacy of immune checkpoint inhibition.

Identification and Characterization of Key Differentially Expressed Genes Associated With Metronomic Dosing of Topotecan in Human Prostate Cancer

Repetitive, low-dose (metronomic; METRO) drug administration of some anticancer agents can overcome drug resistance and increase drug efficacy in many cancers, but the mechanisms are not understood fully. Previously, we showed that METRO dosing of topotecan (TOPO) is more effective than conventional (CONV) dosing in aggressive human prostate cancer (PCa) cell lines and in mouse tumor xenograft models. To gain mechanistic insights into METRO-TOPO activity, in this study we determined the effect of METRO- and CONV-TOPO treatment in a panel of human PCa cell lines representing castration-sensitive/resistant, androgen receptor (+/−), and those of different ethnicity on cell growth and gene expression. Differentially expressed genes (DEGs) were identified for METRO-TOPO therapy and compared to a PCa patient cohort and The Cancer Genome Atlas (TCGA) database. The top five DEGs were SERPINB5, CDKN1A, TNF, FOS, and ANGPT1. Ingenuity Pathway Analysis predicted several upstream regulators and identified top molecular networks associated with METRO dosing, including tumor suppression, anti-proliferation, angiogenesis, invasion, metastasis, and inflammation. Further, the top DEGs were associated with increase survival of PCa patients (TCGA database), as well as ethnic differences in gene expression patterns in patients and cell lines representing African Americans (AA) and European Americans (EA). Thus, we have identified candidate pharmacogenomic biomarkers and novel pathways associated with METRO-TOPO therapy that will serve as a foundation for further investigation and validation of METRO-TOPO as a novel treatment option for prostate cancers.

Drug delivery strategies in maximizing anti-angiogenesis and anti-tumor immunity

Metronomic chemotherapy has been shown to elicit anti-tumor immune response and block tumor angiogenesis distinct from that observed with maximal tolerated dose (MTD) therapy. This review delves into the mechanisms behind anti-tumor immunity and seeks to identify the differential effect of dosing regimens, including daily low-dose and medium-dose intermittent chemotherapy (MEDIC), on both innate and adaptive immune populations involved in observed anti-tumor immune response. Given reports of VEGF/VEGFR blockade antagonizing anti-tumor immunity, drug choice, dose, and selective delivery determined by advanced formulations/vehicles are highlighted as potential sources of innovation for identifying anti-angiogenic modalities that may be combined with metronomic regimens without interrupting key immune players in the anti-tumor response. Engineered drug delivery mechanisms that exhibit extended and local release of anti-angiogenic agents both alone and in combination with chemotherapeutic treatments have also been demonstrated to elicit a potent and potentially systemic anti-tumor immune response, favoring tumor regression and stasis over progression. This review examines this interplay between various cancer models, the host immune response, and select anti-cancer agents depending on drug dosing, scheduling/regimen, and delivery modality.

Metronomic Anti-Cancer Therapy: A Multimodal Therapy Governed by the Tumor Microenvironment

Simple Summary

Metronomic chemotherapy with different mechanisms of action against cancer cells and their microenvironment represents an exceptional holistic cancer treatment. Each type of tumor has its own characteristics, including each individual tumor in each patient. Understanding the complexity of the dynamic interactions that take place between tumor and stromal cells and the microenvironment in tumor progression and metastases, as well as the response of the host and the tumor itself to anticancer therapy, will allow therapeutic actions with long-lasting effects to be implemented using metronomic regimens. This study aims to highlight the complexity of cellular interactions in the tumor microenvironment and summarize some of the preclinical and clinical results that explain the multimodality of metronomic therapy, which, together with its low toxicity, supports an inhibitory effect on the primary tumor and metastases. We also highlight the possible use of nano-therapeutic agents as good partners for metronomic chemotherapy.

Abstract

The concept of cancer as a systemic disease, and the therapeutic implications of this, has gained special relevance. This concept encompasses the interactions between tumor and stromal cells and their microenvironment in the complex setting of primary tumors and metastases. These factors determine cellular co-evolution in time and space, contribute to tumor progression, and could counteract therapeutic effects. Additionally, cancer therapies can induce cellular and molecular responses in the tumor and host that allow them to escape therapy and promote tumor progression. In this study, we describe the vascular network, tumor-infiltrated immune cells, and cancer-associated fibroblasts as sources of heterogeneity and plasticity in the tumor microenvironment, and their influence on cancer progression. We also discuss tumor and host responses to the chemotherapy regimen, at the maximum tolerated dose, mainly targeting cancer cells, and a multimodal metronomic chemotherapy approach targeting both cancer cells and their microenvironment. In a combination therapy context, metronomic chemotherapy exhibits antimetastatic efficacy with low toxicity but is not exempt from resistance mechanisms. As such, a better understanding of the interactions between the components of the tumor microenvironment could improve the selection of drug combinations and schedules, as well as the use of nano-therapeutic agents against certain malignancies.

Metronomic Therapy in Oral Squamous Cell Carcinoma

Metronomic therapy is characterized by drug administration in a low-dose, repeated, and regular manner without prolonged drug-free interval. The two main anticancer mechanisms of metronomic therapy are antiangiogenesis and immunomodulation, which have been demonstrated in several delicate in vitro and in vivo experiments. In contrast to the traditional maximum tolerated dose (MTD) dosing of chemotherapy, metronomic therapy possesses comparative efficacy but greatlydecreases the incidence and severity of treatment side-effects. Clinical trials of metronomic anticancer treatment have revealed promising results in a variety cancer types and specific patient populations such as the elderly and pediatric malignancies. Oral cavity squamous cell carcinoma (OCSCC) is an important health issue in many areas around the world. Long-term survival is about 50% in locally advanced disease despite having high-intensity treatment combined surgery, radiotherapy, and chemotherapy. In this article, we review and summarize the essence of metronomic therapy and focus on its applications in OCSCC treatment.

Inter-Metastatic Heterogeneity of Tumor Marker Expression and Microenvironment Architecture in a Preclinical Cancer Model

BACKGROUND

Preclinical drug development studies rarely consider the impact of a candidate drug on established metastatic disease. This may explain why agents that are successful in subcutaneous and even orthotopic preclinical models often fail to demonstrate efficacy in clinical trials. It is reasonable to anticipate that sites of metastasis will be phenotypically unique, as each tumor will have evolved heterogeneously with respect to gene expression as well as the associated phenotypic outcome of that expression. The objective for the studies described here was to gain an understanding of the tumor heterogeneity that exists in established metastatic disease and use this information to define a preclinical model that is more predictive of treatment outcome when testing novel drug candidates clinically.

METHODS

Female NCr nude mice were inoculated with fluorescent (mKate), Her2/neu-positive human breast cancer cells (JIMT-mKate), either in the mammary fat pad (orthotopic; OT) to replicate a primary tumor, or directly into the left ventricle (intracardiac; IC), where cells eventually localize in multiple sites to create a model of established metastasis. Tumor development was monitored by in vivo fluorescence imaging (IVFI). Subsequently, animals were sacrificed, and tumor tissues were isolated and imaged ex vivo. Tumors within organ tissues were further analyzed via multiplex immunohistochemistry (mIHC) for Her2/neu expression, blood vessels (CD31), as well as a nuclear marker (Hoechst) and fluorescence (mKate) expressed by the tumor cells.

RESULTS

Following IC injection, JIMT-1mKate cells consistently formed tumors in the lung, liver, brain, kidney, ovaries, and adrenal glands. Disseminated tumors were highly variable when assessing vessel density (CD31) and tumor marker expression (mkate, Her2/neu). Interestingly, tumors which developed within an organ did not adopt a vessel microarchitecture that mimicked the organ where growth occurred, nor did the vessel microarchitecture appear comparable to the primary tumor. Rather, metastatic lesions showed considerable variability, suggesting that each secondary tumor is a distinct disease entity from a microenvironmental perspective.

CONCLUSIONS

The data indicate that more phenotypic heterogeneity in the tumor microenvironment exists in models of metastatic disease than has been previously appreciated, and this heterogeneity may better reflect the metastatic cancer in patients typically enrolled in early-stage Phase I/II clinical trials. Similar to the suggestion of others in the past, the use of models of established metastasis preclinically should be required as part of the anticancer drug candidate development process, and this may be particularly important for targeted therapeutics and/or nanotherapeutics.

Metronomic 5-Fluorouracil Delivery Primes Skeletal Muscle for Myopathy but Does Not Cause Cachexia

Skeletal myopathy encompasses both atrophy and dysfunction and is a prominent event in cancer and chemotherapy-induced cachexia. Here, we investigate the effects of a chemotherapeutic agent, 5-fluorouracil (5FU), on skeletal muscle mass and function, and whether small-molecule therapeutic candidate, BGP-15, could be protective against the chemotoxic challenge exerted by 5FU. Additionally, we explore the molecular signature of 5FU treatment. Male Balb/c mice received metronomic tri-weekly intraperitoneal delivery of 5FU (23 mg/kg), with and without BGP-15 (15 mg/kg), 6 times in total over a 15 day treatment period. We demonstrated that neither 5FU, nor 5FU combined with BGP-15, affected body composition indices, skeletal muscle mass or function. Adjuvant BGP-15 treatment did, however, prevent the 5FU-induced phosphorylation of p38 MAPK and p65 NF-B subunit, signalling pathways involved in cell stress and inflammatory signalling, respectively. This as associated with mitoprotection. 5FU reduced the expression of the key cytoskeletal proteins, desmin and dystrophin, which was not prevented by BGP-15. Combined, these data show that metronomic delivery of 5FU does not elicit physiological consequences to skeletal muscle mass and function but is implicit in priming skeletal muscle with a molecular signature for myopathy. BGP-15 has modest protective efficacy against the molecular changes induced by 5FU.

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.

Gene Expression Signatures of a Preclinical Mouse Model during Colorectal Cancer Progression under Low-Dose Metronomic Chemotherapy

Understanding the molecular signatures of colorectal cancer progression under chemotherapeutic treatment will be crucial for the success of future therapy improvements. Here, we used a xenograft-based mouse model to investigate, how whole transcriptome signatures change during metastatic colorectal cancer progression and how such signatures are affected by LDM chemotherapy using RNA sequencing. We characterized mRNAs as well as non-coding RNAs such as microRNAs, long non-coding RNAs and circular RNAs in colorectal-cancer bearing mice with or without LDM chemotherapy. Furthermore, we found that circZNF609 functions as oncogene, since over-expression studies lead to an increased tumor growth while specific knock down results in smaller tumors. Our data represent novel insights into the relevance of non-coding and circRNAs in colorectal cancer and provide a comprehensive resource of gene expression changes in primary tumors and metastases. In addition, we present candidate genes that could be important modulators for successful LDM chemotherapy.

A Phase 1 Dose-Escalation Study of Low-Dose Metronomic Treatment With Novel Oral Paclitaxel Formulations in Combination With Ritonavir in Patients With Advanced Solid Tumors

ModraPac001 (MP1) and ModraPac005 (MP5) are novel oral paclitaxel formulations that are coadministered with the cytochrome P450 3A4 inhibitor ritonavir (r), enabling daily low-dose metronomic (LDM) treatment. The primary aim of this study was to determine the safety, pharmacokinetics and maximum tolerated dose (MTD) of MP1/r and MP5/r. The second aim was to establish the recommended phase 2 dose (RP2D) as LDM treatment. This was an open-label phase 1 trial. Patients with advanced solid tumors were enrolled according to a classical 3+3 design. After initial employment of the MP1 capsule, the MP5 tablet was introduced. Safety was assessed using the Common Terminology Criteria for Adverse Events version 4.02. Pharmacokinetic sampling was performed on days 1, 2, 8, and 22 for determination of paclitaxel and ritonavir plasma concentrations. In this study, 37 patients were treated with up to twice-daily 30-mg paclitaxel combined with twice-daily 100-mg ritonavir (MP5/r 30-30/100-100) in 9 dose levels. Dose-limiting toxicities were nausea, (febrile) neutropenia, dehydration and vomiting. At the MTD/RP2D of MP5/r 20-20/100-100, the maximum paclitaxel plasma concentration and area under the concentration-time curve until 24 hours were 34.6 ng/mL (coefficient of variation, 79%) and 255 ng • h/mL (coefficient of variation, 62%), respectively. Stable disease was observed as best response in 15 of 31 evaluable patients. Based on these results, LDM therapy with oral paclitaxel coadministrated with ritonavir was considered feasible and safe. The MTD and RP2D were determined as MP5/r 20-20/100-100. Further clinical development of MP5/r as an LDM concept, including potential combination treatment, is warranted.

Sodium nitrate co-supplementation does not exacerbate low dose metronomic doxorubicin-induced cachexia in healthy mice

The purpose of this study was to determine whether (1) sodium nitrate (SN) treatment progressed or alleviated doxorubicin (DOX)-induced cachexia and muscle wasting; and (2) if a more-clinically relevant low-dose metronomic (LDM) DOX treatment regimen compared to the high dosage bolus commonly used in animal research, was sufficient to induce cachexia in mice. Six-week old male Balb/C mice (n = 16) were treated with three intraperitoneal injections of either vehicle (0.9% NaCl; VEH) or DOX (4 mg/kg) over one week. To test the hypothesis that sodium nitrate treatment could protect against DOX-induced symptomology, a group of mice (n = 8) were treated with 1 mM NaNO₃ in drinking water during DOX (4 mg/kg) treatment (DOX + SN). Body composition indices were assessed using echoMRI scanning, whilst physical and metabolic activity were assessed via indirect calorimetry, before and after the treatment regimen. Skeletal and cardiac muscles were excised to investigate histological and molecular parameters. LDM DOX treatment induced cachexia with significant impacts on both body and lean mass, and fatigue/malaise (i.e. it reduced voluntary wheel running and energy expenditure) that was associated with oxidative/nitrostative stress sufficient to induce the molecular cytotoxic stress regulator, nuclear factor erythroid-2-related factor 2 (NRF-2). SN co-treatment afforded no therapeutic potential, nor did it promote the wasting of lean tissue. Our data re-affirm a cardioprotective effect for SN against DOX-induced collagen deposition. In our mouse model, SN protected against LDM DOX-induced cardiac fibrosis but had no effect on cachexia at the conclusion of the regimen.

Metronomic chemotherapy offsets HIFα induction upon maximum-tolerated dose in metastatic cancers

Conventional maximum-tolerated dose (MTD) chemotherapy relies on periodic, massive cancer cell ablation events followed by treatment-free intermissions, stereotypically resulting in resistance, relapse, and mortality. Furthermore, MTD chemotherapy can promote metastatic dissemination via activation of a transcriptional program dependent on hypoxia-inducible factor (HIF)-1α and (HIF)-2α (hereafter referred to as HIFα). Instead, frequent low-dose metronomic (LDM) chemotherapy displays less adverse effects while preserving significant pre-clinical anticancer activity. Consequently, we hereby compared the effect of MTD or LDM chemotherapy upon HIFα in models of advanced, metastatic colon and breast cancer. Our results revealed that LDM chemotherapy could offset paralog-specific, MTD-dependent HIFα induction in colon cancers disseminating to the liver and lungs, while limiting HIFα and hypoxia in breast cancer lung metastases. Moreover, we assessed the translational significance of HIFα activity in colorectal and breast TCGA/microarray data, by developing two compact, 11-gene transcriptomic signatures allowing the stratification/identification of patients likely to benefit from LDM and/or HIFα-targeting therapies. Altogether, these results suggest LDM chemotherapy as a potential maintenance strategy to stave off HIFα induction within the intra-metastatic tumor microenvironment.

Intratumoral HLA-DR-/CD33+/CD11b+ Myeloid-Derived Suppressor Cells Predict Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

Capecitabine-based neoadjuvant chemoradiation therapy (nCRT) is currently the mainstay of treatment for locally advanced rectal cancer (LARC), prior to surgical tumor removal. While response to this treatment is partial, it carries significant risk of side effects. As of today, there is no accepted model to predict tumor response, and allow for patient stratification. The level of circulating Myeloid-derived suppressor cells (MDSCs), a subpopulation of early myeloid cells (EMCs), has been shown to correlate with prognosis and response to therapy in advanced colon cancer, but their role in LARC is not clear. We sought to study the effect of intratumoral and circulating levels of different EMCs subpopulations including MDSCs on response to nCRT. We analyzed tumor, normal mucosa, and peripheral blood samples from 25 LARC patients for their different EMCs subpopulation before and after nCRT, and correlated them with degree of pathologic response, as determined postoperatively. In addition, we compared LARC patient to 10 healthy donors and 6 metastatic patients. CD33⁺HLA-DR⁻CD16⁻CD11b⁺EMCs in the circulation of LARC patients were found to inhibit T-cell activation. Furthermore, elevated levels of CD33⁺HLA-DR⁻ myeloid cells were found in the tumor relative to normal mucosa, but not in the circulation when compared to healthy subjects. Moreover, intratumoral, but not circulating levels of MDSCs correlated with clinical stage and response to therapy in patients treated with nCRT, with high levels of MDSCs significantly predicting poor response to nCRT. Importantly, therapy by itself, had significant differential effects on MDSC levels, leading to increased circulating MDSCs, concomitantly with decreasing intratumoral MDSCs. Our results suggest that high levels of intratumoral, but not circulating MDSCs may confer drug resistance due to immunomodulatory effects, and serve as a biomarker for patient stratification and decision-making prior to nCRT.

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.

Microtubule-targeting agents and their impact on cancer treatment

Microtubule-targeting agents (MTAs) constitute a diverse group of chemical compounds that bind to microtubules and affect their properties and function. Disruption of microtubules induces various cellular responses often leading to cell cycle arrest or cell death, the most common effect of MTAs. MTAs have found a plethora of practical applications in weed control, as fungicides and antiparasitics, and particularly in cancer treatment. Here we summarize the current knowledge of MTAs, the mechanisms of action and their role in cancer treatment. We further outline the potential use of MTAs in anti-metastatic therapy based on inhibition of cancer cell migration and invasiveness. The two main problems associated with cancer therapy by MTAs are high systemic toxicity and development of resistance. Toxic side effects of MTAs can be, at least partly, eliminated by conjugation of the drugs with various carriers. Moreover, some of the novel MTAs overcome the resistance mediated by both multidrug resistance transporters as well as overexpression of specific β-tubulin types. In anti-metastatic therapy, MTAs should be combined with other drugs to target all modes of cancer cell invasion.

Comparative evaluation of bolus and fractionated administration modalities for two antibody-cytokine fusions in immunocompetent tumor-bearing mice

Antibody-cytokine fusion proteins are being considered as biopharmaceuticals for cancer immunotherapy. Tumor-homing cytokine fusions typically display an improved therapeutic activity compared to the corresponding unmodified cytokine products, but toxicity profiles at equivalent doses are similar, since side effects are mainly driven by the cytokine concentration in blood. In order to explore avenues to harness the therapeutic potential of antibody-cytokine fusions while decreasing potential toxicity, we compared bolus and fractionated administration modalities for two tumor-targeting antibody-cytokine fusion proteins based on human interleukin-2 (IL2) and murine tumor necrosis factor (TNF) (i.e., L19-hIL2 and L19-mTNF) in two murine immunocompetent mouse models of cancer (F9 and C51). A comparative quantitative biodistribution analysis with radio-labeled protein preparations revealed that a fractionated administration of L19-hIL2 could deliver comparable product doses to the tumor with decreased product concentration in blood and normal organs, compared to bolus injection. By contrast, L19-mTNF (a product that causes a selective vascular shutdown in the tumor) accumulated most efficiently after bolus injection. Fractionated schedules allowed the safe administration of a cumulative dose of L19-mTNF, which was 2.5-times higher than the lethal dose for bolus injection. Dose fractionation led to a prolonged tumor growth inhibition for F9 teratocarcinomas, but not for C51 colorectal tumors, which responded best to bolus injection. Thus, dose fractionation may have different outcomes for the same antibody-cytokine product in different biological contexts.

Trial watch: chemotherapy-induced immunogenic cell death in immuno-oncology

The term ‘immunogenic cell death’ (ICD) denotes an immunologically unique type of regulated cell death that enables, rather than suppresses, T cell-driven immune responses that are specific for antigens derived from the dying cells. The ability of ICD to elicit adaptive immunity heavily relies on the immunogenicity of dying cells, implying that such cells must encode and present antigens not covered by central tolerance (antigenicity), and deliver immunostimulatory molecules such as damage-associated molecular patterns and cytokines (adjuvanticity). Moreover, the host immune system must be equipped to detect the antigenicity and adjuvanticity of dying cells. As cancer (but not normal) cells express several antigens not covered by central tolerance, they can be driven into ICD by some therapeutic agents, including (but not limited to) chemotherapeutics of the anthracycline family, oxaliplatin and bortezomib, as well as radiation therapy. In this Trial Watch, we describe current trends in the preclinical and clinical development of ICD-eliciting chemotherapy as partner for immunotherapy, with a focus on trials assessing efficacy in the context of immunomonitoring.

Anakoinosis: Correcting Aberrant Homeostasis of Cancer Tissue-Going Beyond Apoptosis Induction

The current approach to systemic therapy for metastatic cancer is aimed predominantly at inducing apoptosis of cancer cells by blocking tumor-promoting signaling pathways or by eradicating cell compartments within the tumor. In contrast, a systems view of therapy primarily considers the communication protocols that exist at multiple levels within the tumor complex, and the role of key regulators of such systems. Such regulators may have far-reaching influence on tumor response to therapy and therefore patient survival. This implies that neoplasia may be considered as a cell non-autonomous disease. The multi-scale activity ranges from intra-tumor cell compartments, to the tumor, to the tumor-harboring organ to the organism. In contrast to molecularly targeted therapies, a systems approach that identifies the complex communications networks driving tumor growth offers the prospect of disrupting or "normalizing" such aberrant communicative behaviors and therefore attenuating tumor growth. Communicative reprogramming, a treatment strategy referred to as anakoinosis, requires novel therapeutic instruments, so-called master modifiers to deliver concerted tumor growth-attenuating action. The diversity of biological outcomes following pro-anakoinotic tumor therapy, such as differentiation, trans-differentiation, control of tumor-associated inflammation, etc. demonstrates that long-term tumor control may occur in multiple forms, inducing even continuous complete remission. Accordingly, pro-anakoinotic therapies dramatically extend the repertoire for achieving tumor control and may activate apoptosis pathways for controlling resistant metastatic tumor disease and hematologic neoplasia.

Trends and Challenges in Tumor Anti-Angiogenic Therapies

Excessive abnormal angiogenesis plays a pivotal role in tumor progression and is a hallmark of solid tumors. This process is driven by an imbalance between pro- and anti-angiogenic factors dominated by the tissue hypoxia-triggered overproduction of vascular endothelial growth factor (VEGF). VEGF-mediated signaling has quickly become one of the most promising anti-angiogenic therapeutic targets in oncology. Nevertheless, the clinical efficacy of this approach is severely limited in certain tumor types or shows only transient efficacy in patients. Acquired or intrinsic therapy resistance associated with anti-VEGF monotherapeutic approaches indicates the necessity of a paradigm change when targeting neoangiogenesis in solid tumors. In this context, the elaboration of the conceptual framework of “vessel normalization” might be a promising approach to increase the efficacy of anti-angiogenic therapies and the survival rates of patients. Indeed, the promotion of vessel maturation instead of regressing tumors by vaso-obliteration could result in reduced tumor hypoxia and improved drug delivery. The implementation of such anti-angiogenic strategies, however, faces several pitfalls due to the potential involvement of multiple pro-angiogenic factors and modulatory effects of the innate and adaptive immune system. Thus, effective treatments bypassing relapses associated with anti-VEGF monotherapies or breaking the intrinsic therapy resistance of solid tumors might use combination therapies or agents with a multimodal mode of action. This review enumerates some of the current approaches and possible future directions of treating solid tumors by targeting neovascularization.

Metronomic therapy in pediatric oncology: A snapshot

Metronomic chemotherapy transitioned from the bench to bedside in the early 2000s and since then has carved a niche for itself in pediatric oncology. It has been used solely or in combination with other modalities such as radiotherapy, maximum tolerated dose chemotherapy, and targeted agents in adjuvant, palliative, as well as maintenance settings. No wonder, the resulting medical literature is extremely heterogeneous. In this review, the authors review and synthesize the published literature in pediatric metronomics giving a glimpse of its history, varied applications, and evolution of this genre of chemotherapy in pediatric cancers. Limitations, future prospects, and grey areas are also highlighted.

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.

The metronomic all-oral DEVEC is an effective schedule in elderly patients with diffuse large b-cell lymphoma

Metronomic-chemotherapy (M-CHT) has been rarely assessed in non-Hodgkin-lymphoma (NHL). Therefore, in 2011 we started experimenting a new all-oral M-CHT schedule termed DEVEC (Deltacortene®, etoposide, vinorelbine, cyclophosphamide, +/-Rituximab) in diffuse-large-B-cell lymphoma (DLBCL) patients. Methods Patients with stage Ib-IV were enrolled as follows: 1) treatment-naïve, frail ≥65y, or unfit ≥85y; and 2) relapsed/refractory (R/R) ≥55y. Data were prospectively collected from six Italian centres and compared for efficacy to two reference groups, treated with established iv Rituximab-CHT in 1^st and 2^nd line respectively. Results from April-2011 to March-2018, 17/51(33%) naïve, 21/51(41%) refractory and 13/51(25.5%) relapsed patients started DEVEC; 39/51(76.5%) were de-novo DLBCL; 10/51(19.6%) transformed-DLBCL and 2/51(3.9%) unclassifiable-DLBCL/classical-Hodgkin-lymphoma. The median age was 85y (range=77-93) and 78y (range=57-91) in naïve and R/R respectively and overall the DEVEC patients had very poor features compared to the reference. The rate of grade≥3 haematological-AEs was 43%(95CI=29-58%): G3-neutropenia was the most frequent; grade≥3 extra-haematological-AEs was 13.7% (95%CI=5.4-25.9%), the most frequent was infection. One-year OS and PFS were 67% and 61% for naive, 60% and 50% for reference-naïve respectively; Cox proportional hazard ratio (Cox-PH-ratio) for OS and PFS were 0.69 (95%CI=0.27-1.76;p=.441) and 0.68 (95%CI=0.28-1.62;p=.381) respectively. One-year OS and PFS were 48% and 39% in the R/R, 36% and 17% in the reference-R/R respectively; Cox-PH-ratio for OS and PFS, were 0.76 (95%CI=0.42-1.40; p=.386) and 0.48 (95%CI=0.28-0.82; p=.007) respectively. Conclusion The favourable activity of DEVEC compared to a real-life series and the convenience of an oral administration, may possibly lay the groundwork for a paradigm-shift in the treatment of elderly DLBCL.

Camptothecin Induces PD-L1 and Immunomodulatory Cytokines in Colon Cancer Cells

: Background: Immunotherapy has changed the options for the treatment of various cancer types, but not colon cancer. Current checkpoint blockade approaches are ineffective in a large proportion of colon cancer cases, necessitating studies to elucidate its mechanisms and to identify new targets and strategies against it. Methods: Here, we examined Programmed Death-Ligand 1(PD-L1), cytokine and receptor responses of colon cancer cells exposed to camptothecin (CPT), a clinically used topoisomerase inhibitor. Colon cancer cells were treated with CPT at concentrations of up to 10 µM, and the expressions of PD-L1 and immunoregulatory cytokine genes and receptors were analyzed. Results: PD-L1, a current immunotherapy target for various cancers, was shown to be upregulated in colon cancer cells independent of the cellular p53 status. In metastasis-derived SW620 cells, CPT most extensively upregulated cytokines with T-cell attraction or growth factor functions. Of those modulated genes, SPP1, IL1RN, IL1A, TNFSF13B, OSM, and CSF3 had the most clinical relevance, as their high expression was associated with poor cancer patient overall survival. Conclusions: These findings highlight the need to examine, in preclinical and clinical situations, the potential benefits of combining topoisomerase inhibitors with immune-checkpoint inhibitors.

Treating advanced breast cancer with metronomic chemotherapy: what is known, what is new and what is the future?

The prognosis for patients with locally advanced or metastatic breast cancer (mBC) remains poor, with a median survival of 2–4 years. About 10% of newly diagnosed breast cancer patients present with metastatic disease, and 30%–50% of those diagnosed at earlier stages will subsequently progress to mBC. In terms of ongoing management for advanced/metastatic breast cancer after failure of hormonal therapy, there is a high medical need for new treatment options that prolong the interval to the start of intensive cytotoxic therapy, which is often associated with potentially serious side effects and reduced quality of life. Oral chemotherapeutic agents such as capecitabine and vinorelbine have demonstrated efficacy in patients with mBC, with prolonged disease control and good tolerability. Use of oral chemotherapy reduces the time and cost associated with treatment and is often more acceptable to patients than intravenous drug delivery. Metronomic administration of oral chemotherapy is therefore a promising treatment strategy for some patients with mBC and inhibits tumor progression via multiple mechanisms of action. Ongoing clinical trials are investigating metronomic chemotherapy regimens as a strategy to prolong disease control with favorable tolerability. This article provides an overview of metronomic chemotherapy treatment options in mBC, with perspectives on this therapy from a panel of experts.

Polyester Nanoparticle Encapsulation Mitigates Paclitaxel-Induced Peripheral Neuropathy

Chemotherapy utilizing cytotoxic drugs, such as paclitaxel (PTX), is still a commonly used therapeutic approach to treat both localized and metastasized cancers. Unlike traditional regimens in which PTX is administered at the maximum tolerated dose, alternative regimens like metronomic dosing are beneficial by administering PTX more frequently and in much lower doses exploiting antiangiogenic and immunomodulatory effects. However, PTX-induced peripheral neuropathy and lack of patient compliant dosage forms of PTX are major roadblocks for the successful implementation of metronomic regimens. Because of the success of polyester nanoparticle drug delivery, we explored the potential of nanoparticle-encapsulated paclitaxel (nPTX) in alleviating peripheral neuropathy using a rat model. Rats were injected intraperitoneally with 2 mg/kg body weight of PTX or nPTX on four alternate days, and neuropathic pain and neuronal damage were characterized using behavioral assessments, histology, and immunohistochemistry. The reduction in tactile and nociceptive pressure thresholds was significantly less in nPTX-treated rats than in PTX-treated rats over a 16-day study period. Histological analysis showed that the degree of dorsal root ganglion (DRG) degeneration and reduction in motor neurons in the spinal cord was significantly lower in the nPTX group than the PTX group. Further, immunofluorescence data reveals that nPTX-treated rats had an increased density of a neuronal marker, β-tubulin-III, reduced TUNEL positive cells, and increased high molecular weight neurofilament in the spinal cord, DRG, and sciatic nerves compared with PTX-treated rats. Therefore, this work has important implications in improving risk-benefit profile of PTX, paving the way for metronomic regimens.

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

INTRODUCTION

Metronomic chemotherapy (mCHT) is a treatment regimen in which drugs are administered frequently or continuously and that maintains low, prolonged, and pharmacologically active plasma concentrations of drugs to avoid toxicity associated with traditional chemotherapy regimens, while achieving tumor response. Despite the increasing use of mCHT in patients with metastatic breast cancer (MBC) and the endorsement of mCHT in guidelines, no consensus exists about which patients may substantially benefit from mCHT, which agents can be recommended, and in which treatment setting mCHT is most appropriate.

METHODS

In October 2017, ten international experts in the management of breast cancer convened to develop a report describing the current status of the use of mCHT for the treatment of advanced breast cancer, based not only on current literature but also on their opinion. The Delphi method was used to reach consensus.

RESULTS

A full consensus was reached concerning the acknowledgement that mCHT is not simply a different way of administering chemotherapy but a truly new treatment option. The best-known effect of mCHT is on angiogenesis inhibition, but exciting new data are on the way regarding potential activity on immune system activation. The experts strongly suggest that the ideal patients for mCHT are those with hormone receptor (HR)-positive tumors or those with triple-negative disease. Independently of HR status, mCHT could be an advantageous option for elderly patients, who are often under-treated simply because of their age.

CONCLUSION

Current data support the use of mCHT in selected patients with MBC.

FUNDING

Pierre Fabre.

Recombinant AAV-CEA Tumor Vaccine in Combination with an Immune Adjuvant Breaks Tolerance and Provides Protective Immunity

Carcinoembryonic antigen (CEA) is a human glycoprotein involved in cellular adhesion and expressed during human fetal development. Although expression of CEA largely ceases prior to birth, several human epithelial cancers, including colorectal, gastric, squamous esophageal, and breast carcinomas have been known to overexpress CEA, suggesting its potential as an immunotherapeutic target. Using a transgenic mouse model constitutively expressing human CEA in a spatiotemporal manner as a self-protein and a syngeneic mouse colon cancer cell line, MC38-CEA, overexpressing CEA, we tested the potential of a novel genetic immunotherapy approach against CEA-expressing tumors, using recombinant adeno-associated virus vector encoding CEA (rAAV-CEA) and appropriately timed immune adjuvant application. Results of the study demonstrated breaking of immune tolerance for CEA with this vaccine regimen and an anti-tumor response, resulting in tumor-free survival. Furthermore, tumor challenge of CEA-vaccinated mice with parental MC38 cells not expressing CEA did not result in protection from tumor development, confirming that the protection against tumor development is CEA specific. The study illustrates the feasibility of utilizing rAAV vectors in combination with an immunostimulatory adjuvant to break tolerance to weakly immunogenic self-antigens and for an anti-tumor response.

Clinical Efficacy of a Novel Therapeutic Principle, Anakoinosis

Classic tumor therapy, consisting of cytotoxic agents and/or targeted therapy, has not overcome therapeutic limitations like poor risk genetic parameters, genetic heterogeneity at different metastatic sites or the problem of undruggable targets. Here we summarize data and trials principally following a completely different treatment concept tackling systems biologic processes: the principle of communicative reprogramming of tumor tissues, i.e., anakoinosis (ancient greek for communication), aims at establishing novel communicative behavior of tumor tissue, the hosting organ and organism via re-modeling gene expression, thus recovering differentiation, and apoptosis competence leading to cancer control - in contrast to an immediate, "poisoning" with maximal tolerable doses of targeted or cytotoxic therapies. Therefore, we introduce the term "Master modulators" for drugs or drug combinations promoting evolutionary processes or regulating homeostatic pathways. These "master modulators" comprise a broad diversity of drugs, characterized by the capacity for reprogramming tumor tissues, i.e., transcriptional modulators, metronomic low-dose chemotherapy, epigenetically modifying agents, protein binding pro-anakoinotic drugs, such as COX-2 inhibitors, IMiDs etc., or for example differentiation inducing therapies. Data on 97 anakoinosis inducing schedules indicate a favorable toxicity profile: The combined administration of master modulators, frequently (with poor or no monoactivity) may even induce continuous complete remission in refractory metastatic neoplasia, irrespectively of the tumor type. That means recessive components of the tumor, successively developing during tumor ontogenesis, are accessible by regulatory active drug combinations in a therapeutically meaningful way. Drug selection is now dependent on situative systems characteristics, to less extent histology dependent. To sum up, anakoinosis represents a new substantive therapy principle besides novel targeted therapies.

Enhanced antitumor and anti-angiogenic effects of metronomic Vinorelbine combined with Endostar on Lewis lung carcinoma

Background

Conventional chemotherapy is commonly used to treat non-small cell lung cancer (NSCLC) however it increases therapeutic resistance. In contrast, metronomic chemotherapy (MET) is based on frequent drug administration at lower doses, resulting in inhibition of neovascularization and induction of tumor dormancy. This study aims to evaluate the inhibitory effects, adverse events, and potential mechanisms of MET Vinorelbine (NVB) combined with an angiogenesis inhibitor (Endostar).

Methods

Circulating endothelial progenitor cells (CEPs), apoptosis rate, expression of CD31, vascular endothelial growth factor (VEGF), hypoxia inducible factor-1 (HIF-1α) were determined using flow cytometry, western blot analysis, immunofluorescence staining and Enzyme-linked immunosorbent assay (ELISA) analysis. And some animals were also observed using micro fluorine-18-deoxyglucose PET/computed tomography (¹⁸F-FDG PET/CT) to identify changes by comparing SUVmax values. In addition, white blood cell (WBC) counts and H&E-stained sections of liver, lungs, kidney, and heart were performed in order to monitor toxicity assessments.

Results

We found that treatment with MET NVB + Endo was most effective in inhibiting tumor growth, decreasing expression of CD31, VEGF, HIF-1α, and CEPs, and reducing side effects, inducing apoptosis, such as expression of Bcl-2, Bax and caspase-3. Administration with a maximum tolerated dose of NVB combined with Endostar (MTD NVB + Endo) demonstrated similar anti-tumor effects, including changes in glucose metabolism with micro fluorine-18-deoxyglucose PET/computed tomography (¹⁸F-FDG PET/CT) imaging, however angiogenesis was not inhibited. Compared with either agent alone, the combination of drugs resulted in better anti-tumor effects.

Conclusion

These results indicated that MET NVB combined with Endo significantly enhanced anti-tumor and anti-angiogenic responses without overt toxicity in a xenograft model of human lung cancer.

CDK8 Selectively Promotes the Growth of Colon Cancer Metastases in the Liver by Regulating Gene Expression of TIMP3 and Matrix Metalloproteinases

: Unresectable hepatic metastases of colon cancer respond poorly to existing therapies and are a major cause of colon cancer lethality. In this study, we evaluated the therapeutic viability of targeting the mediator kinase CDK8, an early clinical stage drug target, as a means to suppress metastasis of colon cancer. CDK8 was amplified or overexpressed in many colon cancers and CDK8 expression correlated with shorter patient survival. Knockdown or inhibition of CDK8 had little effect on colon cancer cell growth but suppressed metastatic growth of mouse and human colon cancer cells in the liver. This effect was due in part to inhibition of already established hepatic metastases, indicating therapeutic potential of CDK8 inhibitors in the metastatic setting. In contrast, knockdown or inhibition of CDK8 had no significant effect on the growth of tumors implanted subcutaneously, intrasplenically, or orthotopically in the cecum. CDK8 mediated colon cancer growth in the liver through downregulation of matrix metalloproteinase (MMP) inhibitor TIMP3 via TGFβ/SMAD-driven expression of a TIMP3-targeting microRNA, miR-181b, along with induction of Mmp3 in murine or MMP9 in human colon cancer cells via Wnt/β-catenin-driven transcription. These findings reveal a new mechanism for negative regulation of gene expression by CDK8 and a site-specific role for CDK8 in colon cancer hepatic metastasis. Our results indicate the utility of CDK8 inhibitors for the treatment of colon cancer metastases in the liver and suggest that CDK8 inhibitors may be considered in other therapeutic settings involving TGFβ/SMAD or Wnt/β-catenin pathway activation. SIGNIFICANCE: These findings demonstrate that inhibition of the transcription-regulating kinase CDK8 exerts a site-specific tumor-suppressive effect on colon cancer growth in the liver, representing a unique therapeutic opportunity for the treatment of advanced colon cancer.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/23/6594/F1.large.jpg.

Metronomic Chemotherapy with Vinorelbine Produces Clinical Benefit and Low Toxicity in Frail Elderly Patients Affected by Advanced Non-Small Cell Lung Cancer

BACKGROUND

Lung cancer is the leading cause of death worldwide. The treatment choice for advanced stage of lung cancer may depend on histotype, performance status (PS), age, and comorbidities. In the present study, we focused on the effect of metronomic vinorelbine treatment in elderly patients with advanced unresectable non-small cell lung cancer (NSCLC).

METHODS

From January 2016 to December 2016, 44 patients affected by non-small cell lung cancer referred to our oncology day hospital were progressively analyzed. The patients were treated with oral vinorelbine 30 mg x 3/wk or 40 mg x 3/wk meaning one day on and one day off. The patients were older than 60, stage IIIB or IV, ECOG PS ≥ 1, and have at least one important comorbidity (renal, hepatic, or cardiovascular disease). The schedule was based on ECOG-PS and comorbidities. The primary endpoint was progression-free survival (PFS). PFS was used to compare patients based on different scheduled dosage (30 or 40 mg x3/weekly) and age (more or less than 75 years old) as exploratory analysis. We also evaluated as secondary endpoint toxicity according to Common Toxicity Criteria Version 2.0.

RESULTS

Vinorelbine showed a good safety profile at different doses taken orally and was effective in controlling cancer progression. The median overall survival (OS) was 12 months. The disease control rate (DCR) achieved 63%. The median PFS was 9 months. A significant difference in PFS was detected comparing patients aged below with those over 75, and the HR value was 0.72 (p<0.05). Not significant was the difference between groups with different schedules.

CONCLUSIONS

This study confirmed the safety profile of metronomic vinorelbine and its applicability for patients unfit for standard chemotherapies and adds the possibility of considering this type of schedule not only for very elderly patients.

Vinorelbine, cyclophosphamide and 5-FU effects on the circulating and intratumoural landscape of immune cells improve anti-PD-L1 efficacy in preclinical models of breast cancer and lymphoma

Background

Anti-PD-1 and anti-PD-L1 checkpoint inhibitors (CIs) are clinically active in many types of cancer. However, only a minority of patients achieve a complete and/or long-lasting clinical response. We studied the effects of different doses of three widely used, orally active chemotherapeutics (vinorelbine, cyclophosphamide and 5-FU) over local and metastatic tumour growth, and the landscape of circulating and tumour-infiltrating immune cells involved in CI activity.

Methods

Immunocompetent Balb/c mice were used to generate models of breast cancer (BC) and B-cell lymphoma. Vinorelbine, cyclophosphamide and 5-FU (alone or in combination with CIs), were given at low-dose metronomic, medium, or maximum tolerable dosages.

Results

Cyclophosphamide increased circulating myeloid derived suppressor cells (MDSC). Vinorelbine, cyclophosphamide and 5-FU reduced circulating APCs. Vinorelbine and cyclophosphamide (at medium/high doses) reduced circulating Tregs. Cyclophosphamide (at low doses) and 5-FU (at medium doses) slightly increased circulating Tregs. Cyclophosphamide was the most potent drug in reducing circulating CD3+CD8+ and CD3+CD4+ T cells. Vinorelbine, cyclophosphamide and 5-FU reduced the number of circulating B cells, with cyclophosphamide showing the most potent effect. Vinorelbine reduced circulating NKs, whereas cyclophosphamide and 5-FU, at low doses, increased circulating NKs. In spite of reduced circulating T, B and NK effector cells, preclinical synergy was observed between chemotherapeutics and anti-PD-L1. Most-effective combinatorial regimens where associated with neoplastic lesions enriched in B cells, and, in BC-bearing mice (but not in mice with lymphoma) also in NK cells.

Conclusions

Vinorelbine, cyclophosphamide and 5-FU have significant preclinical effects on circulating and tumour-infiltrating immune cells and can be used to obtain synergy with anti-PD-L1.

Metronomic vinorelbine is directly active on Non Small Cell Lung Cancer cells and sensitizes the EGFRL858R/T790M cells to reversible EGFR tyrosine kinase inhibitors

Metronomic vinorelbine (mVNR) has been described primarily as an antiangiogenic therapy, and no direct effects of mVNR on Non Small Cell Lung Cancer (NSCLC) cells has yet been demonstrated. The aims of this study were i) to establish the direct activity of mVNR on NSCLC cells either EGFR wt or EGFR^L858R/T790M, and ii) to quantify the synergism of the combination with reversible EGFR tyrosine kinase inhibitors (TKIs), investigating the underlying mechanism of action. Proliferation assays were performed on A-549 (wt EGFR^high), H-292 (EGFR-wt), H-358 (EGFR-wt), H-1975 (EGFR^L858R/T790M) NSCLC cell lines exposed to mVNR, its active metabolite deacetyl-VNR (D-VNR), gefitinib and erlotinib for 144 h treatments. The synergism between mVNR and EGFR TKIs was determined by the combination index (CI) in EGFR-wt and H-1975 NSCLC cells. Cyclin-D1 and ABCG2 genes expression and protein levels were measured by RT-PCR and ELISA assays, as well as the phosphorylation of ERK1/2 and Akt. Intracellular concentrations of EGFR TKIs and VNR were investigated with a mass spectrometry system. mVNR, and its active metabolite D-VNR, were extremely active on NSCLC cells, in particular on H-1975 (IC₅₀ = 13.56 ± 2.77 pM), resistant to TKIs. mVNR inhibited the phosphorylation of ERK1/2 and Akt and significantly decreased the expression of both cyclin-D1 and ABCG2 m-RNA and protein. The simultaneous combination of VNR and reversible EGFR TKIs showed a strong synergism on EGFR-wt NSCLC cells and on H-1975 cells (e.g. CI = 0.501 for 50% of affected cells), increasing the intracellular concentrations of EGFR TKIs (e.g. +50.5% vs. gefitinib alone). In conclusions, mVNR has direct effects on NSCLC cells and sensitizes resistant cells to EGFR TKIs, increasing their intracellular concentrations.

Survival Impact of CAPOX Versus FOLFOX in the Adjuvant Treatment of Stage III Colon Cancer

BACKGROUND

Capecitabine and oxaliplatin (CAPOX) and folinic acid, fluorouracil, and oxaliplatin (FOLFOX) are both used in the adjuvant treatment of colon cancer, and while their efficacy is assumed to be similar, they have not been directly compared. We reviewed the toxicity profiles, relative dose intensity (RDI), and survival associated with these regimens across a multi-institutional cohort.

PATIENTS AND METHODS

We identified 394 consecutively treated patients with stage III colon cancer who received an oxaliplatin-containing regimen. RDI was defined as the total dose received divided by the intended total dose if all cycles were received.

RESULTS

FOLFOX was associated with increased mucositis (6.2% vs. 0.7%, P = .0069) and neutropenia (25.9% vs. 8.6%, P < .0001), while CAPOX was associated with increased dose-limiting toxicities (DLTs) (90.7% vs. 80.2%, P = .0055), diarrhea (31.8% vs. 9.0%, P < .0001), and hand-foot syndrome (19.9% vs. 2.1%, P < .0001). Higher median RDI of fluoropyrimidine (93.7% vs. 80.0%, P < .0001) and oxaliplatin (87.2% vs. 76.3%, P < .0001) was noted for patients receiving FOLFOX. Reducing the duration from 6 to 3 months would have prevented 28.7% of FOLFOX and 20.5% of CAPOX patients from ever experiencing a DLT (P = .0008). Overall survival did not differ by regimen (hazard ratio = 0.73; 95% confidence interval 0.45-1.22; P = .24). However, CAPOX was associated with improved disease-free survival (3-year disease-free survival 83.8% vs. 73.4%, P = .022), which remained significant in high-risk (T4 or N2) (P = .039) but not low-risk patients (P = .19).

CONCLUSION

CAPOX may be associated with improved disease-free survival despite greater toxicities and lower RDI. Reducing adjuvant chemotherapy duration to 3 months would prevent 26% of patients from ever experiencing a DLT.

Trial watch: Immunogenic cell death induction by anticancer chemotherapeutics

The expression "immunogenic cell death" (ICD) refers to a functionally unique form of cell death that facilitates (instead of suppressing) a T cell-dependent immune response specific for dead cell-derived antigens. ICD critically relies on the activation of adaptive responses in dying cells, culminating with the exposure or secretion of immunostimulatory molecules commonly referred to as "damage-associated molecular patterns". Only a few agents can elicit bona fide ICD, including some clinically established chemotherapeutics such as doxorubicin, epirubicin, idarubicin, mitoxantrone, bleomycin, bortezomib, cyclophosphamide and oxaliplatin. In this Trial Watch, we discuss recent progress on the development of ICD-inducing chemotherapeutic regimens, focusing on studies that evaluate clinical efficacy in conjunction with immunological biomarkers.