Next generation metronomic chemotherapy-report from the Fifth Biennial International Metronomic and Anti-angiogenic Therapy Meeting, 6-8 May 2016, Mumbai

Promotion of tumor angiogenesis and growth induced by low-dose antineoplastic agents via bone-marrow-derived cells in tumor tissues

Background

More research is needed to solidify the basis for reasonable metronomic chemotherapy regimens due to the inconsistent clinical outcomes from studies on metronomic chemotherapy with antineoplastic agents, along with signs of a nonlinear dose-response relationship at low doses. The present study therefore explored the dose-response relationships of representative antineoplastic agents in low dose ranges and their underlying mechanisms.

Methods

Cyclophosphamide (CPA) and 5-fluorouracil (5-Fu) were employed to observe the effects of the frequent administration of low-dose antineoplastic agents on tumor growth, tumor angiogenesis, and bone-marrow-derived cell (BMDC) mobilization in mouse models. The effects of antineoplastic agents on tumor and endothelial cell functions with or without BMDCs were analyzed in vitro.

Results

Tumor growth and metastasis were significantly promoted after the administration of CPA or 5-Fu at certain low dose ranges, and were accompanied by enhanced tumor angiogenesis and proangiogenic factor expression in tumor tissues, increased proangiogenic BMDC release in the circulating blood, and augmented proangiogenic BMDC retention in tumor tissues. Low concentrations of CPA or 5-Fu were found to significantly promote tumor cell migration and invasion, and enhance BMDC adhesion to endothelial cells in vitro.

Conclusion

These results suggest that there are risks in empirical metronomic chemotherapy using low-dose antineoplastic agents and the optimal dosage and administration schedule of antineoplastic agents need to be determined through further research.

A multiscale cell-based model of tumor growth for chemotherapy assessment and tumor-targeted therapy through a 3D computational approach

OBJECTIVES

Computational modeling of biological systems is a powerful tool to clarify diverse processes contributing to cancer. The aim is to clarify the complex biochemical and mechanical interactions between cells, the relevance of intracellular signaling pathways in tumor progression and related events to the cancer treatments, which are largely ignored in previous studies.

MATERIALS AND METHODS

A three-dimensional multiscale cell-based model is developed, covering multiple time and spatial scales, including intracellular, cellular, and extracellular processes. The model generates a realistic representation of the processes involved from an implementation of the signaling transduction network.

RESULTS

Considering a benign tumor development, results are in good agreement with the experimental ones, which identify three different phases in tumor growth. Simulating tumor vascular growth, results predict a highly vascularized tumor morphology in a lobulated form, a consequence of cells' motile behavior. A novel systematic study of chemotherapy intervention, in combination with targeted therapy, is presented to address the capability of the model to evaluate typical clinical protocols. The model also performs a dose comparison study in order to optimize treatment efficacy and surveys the effect of chemotherapy initiation delays and different regimens.

CONCLUSIONS

Results not only provide detailed insights into tumor progression, but also support suggestions for clinical implementation. This is a major step toward the goal of predicting the effects of not only traditional chemotherapy but also tumor-targeted therapies.

Metro-SMHOP 01: Metronomics combination with cyclophosphamide-etoposide and valproic acid for refractory and relapsing pediatric malignancies

BACKGROUND

In low- and middle-income countries, therapeutic options for advanced, refractory, or relapsing malignancies are limited due to local constraints such as cost of drugs, distance from oncology centers, and lack of availability of new anticancer drugs. Metronomics, which combines metronomic chemotherapy (MC) and drug repositioning, allows for the provision of new therapeutic options for patients in this setting.

AIM OF THE STUDY

To evaluate the activity and toxicity of a metronomic regimen in Moroccan pediatric patients with refractory or relapsing malignancies.

PATIENTS AND METHODS

From July 2014 to January 2018, patients with refractory/relapsing solid tumors treated in five pediatric oncology centers were consecutively enrolled. The metronomic regimen consisted of 28-day cycles with daily oral administration of cyclophosphamide (30 mg/m² ) from days 1 to 21, together with oral etoposide (25 mg/m² ) from days 1 to 21 followed by break of one week and daily valproic acid (20 mg/kg) from days 1 to 28.

RESULTS

Ninety-eight children (median age, 8 years) were included. Underlying malignancies were neuroblastoma (24 patients), Ewing sarcoma (18), osteosarcoma (14), rhabdomyosarcoma (14), and miscellaneous tumors (28). A total of 557 cycles were given (median: 6; range, 1-18 cycles). One-year progression-free survival of our patients was 19%, and one-year overall survival was 22%. Complete response was obtained in three cases (3%), partial response in 11 cases (11%), and tumor stabilization for more than six months in 28 cases (28%).

CONCLUSION

This three-drug metronomic combination was well tolerated and associated with tumor response and disease stabilization in 42 patients even for a long period.

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.

Immunogenic chemotherapy: Dose and schedule dependence and combination with immunotherapy

Conventional cytotoxic cancer chemotherapy is often immunosuppressive and associated with drug resistance and tumor regrowth after a short period of tumor shrinkage or growth stasis. However, certain cytotoxic cancer chemotherapeutic drugs, including doxorubicin, mitoxantrone, and cyclophosphamide, can kill tumor cells by an immunogenic cell death pathway, which activates robust innate and adaptive anti-tumor immune responses and has the potential to greatly increase the efficacy of chemotherapy. Here, we review studies on chemotherapeutic drug-induced immunogenic cell death, focusing on how the choice of a conventional cytotoxic agent and its dose and schedule impact anti-tumor immune responses. We propose a strategy for effective immunogenic chemotherapy that employs a modified metronomic schedule for drug delivery, which we term medium-dose intermittent chemotherapy (MEDIC). Striking responses have been seen in preclinical cancer models using MEDIC, where an immunogenic cancer chemotherapeutic agent is administered intermittently and at an intermediate dose, designed to impart strong and repeated cytotoxic damage to tumors, and on a schedule compatible with activation of a sustained anti-tumor immune response, thereby maximizing anti-cancer activity. We also discuss strategies for combination chemo-immunotherapy, and we outline approaches to identify new immunogenic chemotherapeutic agents for drug development.

An Algorithm to Define the Optimum Biological Dose of Metronomic Chemotherapy

The best effective dose of a chemotherapy is defined using the maximum tolerated dose (MTD) of toxicity. It is possible that the toxicity of a dose may increase when the dose-response curve is not monotonic. In the case of metronomic chemotherapy (MC) a 1/10th level of MC dose is considered as a targeted dose of therapy and is safer in terms of toxicity levels. The objective of this study is to develop an algorithm based on the dose response model of MC to evaluate the best effective dose based on the molecular target agent. The molecular target agent is defined as the optimal biological dose achieved by the best effective dose, as the lowest dose with the highest rate of safety and efficacy. The first proposed design is parametric and assumes a logistic dose-efficacy curve for dose determination, and the second design uses quadratic regression to identify the optimal biological dose. We conducted extensive simulation studies to investigate the operating characteristics of the proposed designs. Simulation studies provide a possible way to decide on the best effective dose of MC to be considered in further phases through the finding of the optimal biological dose. The proposed design is assumed, with the threshold value of optimum biological dose (OBD), to detect the best dose of MC. This consistent design with specific dose response models can be recommended for practice.

Drug repurposing in malignant pleural mesothelioma: a breath of fresh air?

Drug repurposing is the use of known drugs for new indications. Malignant pleural mesothelioma (MPM) is a rare cancer with a poor prognosis. So far, few treatments have been approved in this disease. However, its incidence is expected to increase significantly, particularly in developing countries. Consequently, drug repurposing appears as an attractive strategy for drug development in MPM, since the known pharmacology and safety profile based on previous approvals of repurposed drugs allows for faster time-to-market for patients and lower treatment cost. This is critical in low- and middle-income countries where access to expensive drugs is limited. This review assesses the published preclinical and clinical data about drug repurposing in MPM.In this review, we identified 11 therapeutic classes that could be repositioned in mesothelioma. Most of these treatments have been evaluated in vitro, half have been evaluated in vivo in animal models of MPM and only three (i.e. valproate, thalidomide and zoledronic acid) have been investigated in clinical trials, with limited benefits so far. Efforts could be coordinated to pursue further investigations and test promising drugs identified in preclinical experiments in appropriately designed clinical trials.

Traditional Herbal Formula NPC01 Exerts Antiangiogenic Effects through Inhibiting the PI3K/Akt/mTOR Signaling Pathway in Nasopharyngeal Carcinoma Cells

Antiangiogenic therapy is vital in nasopharyngeal carcinoma (NPC) treatment. NPC01 has already been successfully used in treating patients with NPC in clinical practice and exerted an excellent antiangiogenetic effect. However, the potential molecular mechanism underlying the antitumor effect of NPC01 has not been well explored. The present study demonstrated that NPC01 could significantly inhibit cell proliferation and induce cell apoptosis in a dose-dependent manner in human NPC cell lines. Furthermore, NPC01 exerted antiproliferative and antiangiogenic effects in NPC xenograft mice. Moreover, the study showed that NPC01 could significantly decrease the expression of angiogenesis-associated factors including hypoxia-inducible factor-1α and vascular endothelial growth factor. Additionally, the decreased expression of these angiogenesis-associated factors could be due to the inhibition of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway (PI3K/Akt/mTOR). In conclusion, the results proposed that NPC01 could exert its antitumor effect by suppressing the PI3K/Akt/mTOR signaling pathway. Further studies are warranted to elucidate the molecular mechanism.

Metronomic and metronomic-like therapies in neuroendocrine tumors - Rationale and clinical perspectives

Metronomic therapy is characterized by the administration of regular low doses of certain drugs with very low toxicity. There have been numerous debates over the empirical approach of this regimen, but fewest side effects are always something to consider in order to improve patients' quality of life. Neuroendocrine tumors (NETs) are rare malignancies relatively slow-growing; therefore their treatment is often chronic, involving several different therapies for tumor growth control. Knowing that these tumors are highly vascularized, the anti-angiogenic aspect is highly regarded as something to be targeted in all patients harboring NETs. Additionally the metronomic schedule has proved to be effective on an immunological level, rendering this approach as a multi-targeted therapy. Rationalizing that advanced NETs are in many cases a chronic disease, with which patients can live for as long as possible, a systemic therapy with regular low doses and a very low toxicity is in many cases a judicious manner of pursuing stabilization. Metronomic schedule is usually correlated with chemotherapy in oncology, but other therapies, such as radiotherapy and biotherapy can be delivered in a metronomic like manner. This review describes clinical trials and case series involving metronomic therapies alone or in combination in patients with advanced NETs. Nowadays level of evidence about metronomic therapy in NETs is quite low, therefore future prospective clinical studies are needed to validate the metronomic approach in specific clinical settings.