Metronomic chemotherapy: changing the paradigm that more is better

Selective tubulin-binding drugs induce pericyte phenotype switching and anti-cancer immunity

The intratumoral immune milieu is crucial for the success of anti-cancer immunotherapy. We show here that stromal modulation by the tubulin-binding anti-cancer drugs combretastatin A4 (CA-4) and eribulin improved tumor perfusion and anti-tumor immunity. This was achieved by reverting highly proliferative, angiogenic pericytes into a quiescent, contractile state which durably normalized the vascular bed and reduced hypoxia in mouse models of pancreatic neuroendocrine cancer, breast cancer and melanoma. The crucial event in pericyte phenotype switching was RhoA kinase activation, which distinguished CA-4 and eribulin effects from other anti-mitotic drugs such as paclitaxel and vinorelbine. Importantly, eribulin pre-treatment sensitized tumors for adoptive T cell therapy or checkpoint inhibition resulting in effector cell infiltration and better survival outcomes in mice. In breast cancer patients, eribulin neoadjuvant treatment induced pericyte maturity and RhoA kinase activity indicating similar vessel remodeling effects as seen in mice. Moreover, a contractile pericyte signature was associated with overall better survival outcome in two independent breast cancer cohorts. This underscores the potential of re-purposing specific anti-cancer drugs to enable synergistic complementation with emerging immunotherapies.

Adjuvant Metronomic Chemotherapy After Surgery in pT1-T2 N0 M0 HER2-Positive and ER/PR-Positive Breast Cancer Plus Targeted Therapy, Anti-Hormonal Therapy, and Radiotherapy, with or Without Immunotherapy: A New Operational Proposal

Breast cancer is the most common and deadly female-specific malignancy in the world. Four immunohistochemical subtypes are distinguished: luminal A, luminal B, HER2-positive, and triple-negative. In turn, the HER2-positive subtype presents two variants depending on the status of the hormone receptors. The variant that expresses them can benefit from both anti-HER2 and anti-hormonal therapy. Today, MCTP finds application in maintenance therapy after standard of care and in advanced breast cancer when the patient's clinical condition is already seriously compromised by metastatic disease; in this context, it is used as a first-line treatment, in pre-treated subjects, or as a rescue treatment. Here, the use of adjuvant oral MCTP after surgery at an early stage in HER-2 and hormone-positive local breast cancer is proposed, where effective treatment options are available, such as anti-HER2 therapy (e.g., trastuzumab, pertuzumab), anti-hormonal therapy (e.g., tamoxifen, letrozole), radiotherapy, and, in case of strong PD-1 positivity, immunotherapy.

Understanding therapeutic tolerance through a mathematical model of drug-induced resistance

There is growing recognition that phenotypic plasticity enables cancer cells to adapt to various environmental conditions. An example of this adaptability is the ability of an initially sensitive population of cancer cells to acquire resistance and persist in the presence of therapeutic agents. Understanding the implications of this drug-induced resistance is essential for predicting transient and long-term tumor dynamics subject to treatment. This paper introduces a mathematical model of drug-induced resistance which provides excellent fits to time-resolved in vitro experimental data. From observational data of total numbers of cells, the model unravels the relative proportions of sensitive and resistance subpopulations and quantifies their dynamics as a function of drug dose. The predictions are then validated using data on drug doses that were not used when fitting parameters. Optimal control techniques are then utilized to discover dosing strategies that could lead to better outcomes as quantified by lower total cell volume.

Results of the Latin American Pediatric Oncology Group (GALOP-2011) Trial for Patients With Localized Ewing Sarcoma: A Multicentric Study of Interval-Compressed Multiagent Chemotherapy

BACKGROUND

GALOP investigators developed a prospective cooperative protocol for localized Ewing sarcoma (ES) incorporating interval-compressed chemotherapy (VDC/IE, vincristine, doxorubicin, cyclophosphamide/ifosfamide and etoposide). After completing conventional treatment, patients were randomized to 1 year of metronomic chemotherapy (vinblastine and cyclophosphamide).

METHODS

Phase III randomized prospective trial. Induction consisted of six alternating cycles of VDC/IE every 14 days, followed by local control, and eight cycles of consolidation every 21 days. After consolidation, patients were randomized 1:1 to metronomic chemotherapy or stop treatment, balanced by age (>/< 14 years-old), sex (M/F), site (pelvic/non-pelvic), and size (>/< 8 cm). The results of randomization will be published elsewhere with longer follow-up.

RESULTS

Between 2011 and 2019, 315 patients (59.7% male, median age 11.0 years) were recruited across 34 centers in Argentina, Brazil, Chile, and Uruguay. The most frequent localizations were axial (45.1%), extremity (38.1%), and pelvic (16.8%). The median time interval between cycles was 19 and 22 days at induction and consolidation, respectively. There were no unexpected toxicity or toxic deaths related to interval compression. The overall response rate post-induction was 81.6%. Local treatment with surgery (50.8%), radiotherapy (19.7%), or a combination (26%) was performed in 304 (96.5%) patients. With a median follow-up of 50 months (range: 1.67-121.7), the 5-year overall and event-free survivals were 68.6% (SE: 0.030) and 63.7% (SE: 0.029), respectively.

CONCLUSION

Implementation of a multi-institutional protocol with the strategy of interval-compressed induction for ES in South America was feasible with favorable results. This success is attributed to rigorous protocol adherence, extensive educational efforts, and a strong emphasis on data quality maintenance, demonstrating a reproducible model for countries with similar resource limitations.

The future of metronomic chemotherapy: experimental and computational approaches of drug repurposing

Metronomic chemotherapy (MC), long-term continuous administration of anticancer drugs, is gaining attention as an alternative to the traditional maximum tolerated dose (MTD) chemotherapy. By combining MC with other treatments, the therapeutic efficacy is enhanced while minimizing toxicity. MC employs multiple mechanisms, making it a versatile approach against various cancers. However, drug resistance limits the long-term effectiveness of MC, necessitating ongoing development of anticancer drugs. Traditional drug discovery is lengthy and costly due to processes like target protein identification, virtual screening, lead optimization, and safety and efficacy evaluations. Drug repurposing (DR), which screens FDA-approved drugs for new uses, is emerging as a cost-effective alternative. Both experimental and computational methods, such as protein binding assays, in vitro cytotoxicity tests, structure-based screening, and several types of association analyses (Similarity-Based, Network-Based, and Target Gene), along with retrospective clinical analyses, are employed for virtual screening. This review covers the mechanisms of MC, its application in various cancers, DR strategies, examples of repurposed drugs, and the associated challenges and future directions.

Metronomic Chemotherapy After Palliative Radiotherapy in Rare Soft Tissue Sarcomas: An Insight into Radiation Therapy and the Immune Response

Soft tissue sarcomas (STSs) account for less than 1% of the overall human burden of malignant tumors. The intent of treatment in metastatic STSs is palliative and prognosis is dismal. This study aims to evaluate the role of low-dose radiotherapy and low-dose oral metronomic therapy in heavily pretreated metastatic infrequent STSs. This study was conducted in a prospective observational manner in a tertiary care center. A total of 16 cases met the inclusion criteria for enrollment in the study group. The diagnosis of all subtypes of STS was confirmed by histopathology and immunohistochemistry or cytogenetic studies. All the enrolled patients with metastatic STSs who were treated with surgery and two lines of chemotherapy were initially treated with low-dose radiotherapy of 20 Gy in 5 fractions or 30 Gy in 10 fractions according to the ECOG performance status of the patient. Out of 16 patients, seven patients (43.75%) were treated with 20 Gy, 5#, and 9 patients (56.25%) were treated with 30 Gy, 10# radiotherapy (RT). Out of 16 patients, four were of malignant fibrohistiocytic sarcoma, three were angiosarcoma, three were malignant phylloides tumor of the breast, two were fibrosarcoma, and one patient from each of the following subtypes inflammatory myofiroblastic tumor, leiomyosarcoma, synovial sarcoma, and dermato fibrosarcoma protuberance. Out of 16 patients, seven (43.75%) had a partial response (PR), nine (56.25%) had stable disease (SD) at 3 months, and all the patients had SD at 6 months of evaluation. All the patients had enjoyed a better quality of life as compared to their life during injectable chemotherapy. Targeted low-dose radiation and metronomic chemotherapy leads to quantifiable antiangiogeneic effects and immune effects in the local tumor microenvironment, and influences circulating immune mediators and anti-angiogenesis that could potentially help eradicate disease both within and outside the radiation treatment field.

A doxorubicin loaded chitosan-poloxamer in situ implant for the treatment of breast cancer

Breast cancer is a serious concern for many women worldwide. Drug-loaded implants have shown several benefits over systemic administrations. To provide anti-cancer drugs with controlled release and reduced systemic toxicity, biodegradable in situ implants have attracted a lot of attention. In the present study, we aimed to design and optimize a doxorubicin-loaded chitosan-poloxamer in situ implant for breast cancer treatment. Utilizing Box-Behnken Design and a Quality-by-Design (QbD) methodology, the in situ implant was prepared with chitosan (X1), poloxamer 407 concentration (X2), and stirring time (X3) as the independent variables. It was characterized for its in vitro gelation time, pH, rheology, and morphology, and evaluated based on drug release profile, in vitro cytotoxicity activities, in vitro anti-inflammatory potential, in vitro cellular uptake, and in vivo anti-inflammatory and pharmacokinetics to ensure their therapeutic outcomes. The results revealed that the prepared formulation showed a gelation time of 26 ± 0.2 s with a viscosity of 8312.6 ± 114.2 cPs at 37 °C. The developed formulation showed better cytotoxic activity in MCF-7 cell lines compared to the free drug solution. It demonstrated reduced levels of pro-inflammatory cytokines in RAW 264.7 macrophages. Further, the prepared in situ implant increases the intracellular accumulation of DOX in the MCF-7 cells. The in vivo pharmacokinetic investigations depicted an increase in t 1/2 and a decrease in AUC of the developed formulation resulting in prolonged drug release and there could be a lower drug concentration in the bloodstream than for the free drug. Therefore, the developed in situ implant may offer a viable option for breast cancer treatment.

The Complex Tumor Microenvironment in Ovarian Cancer: Therapeutic Challenges and Opportunities

The tumor microenvironment (TME) in ovarian cancer (OC) has much greater complexity than previously understood. In response to aggressive pro-angiogenic stimulus, blood vessels form rapidly and are dysfunctional, resulting in poor perfusion, tissue hypoxia, and leakiness, which leads to increased interstitial fluid pressure (IFP). Decreased perfusion and high IFP significantly inhibit the uptake of therapies into the tumor. Within the TME, there are numerous inhibitor cells, such as myeloid-derived suppressor cells (MDSCs), tumor association macrophages (TAMs), regulatory T cells (Tregs), and cancer-associated fibroblasts (CAFs) that secrete high numbers of immunosuppressive cytokines. This immunosuppressive environment is thought to contribute to the lack of success of immunotherapies such as immune checkpoint inhibitor (ICI) treatment. This review discusses the components of the TME in OC, how these characteristics impede therapeutic efficacy, and some strategies to alleviate this inhibition.

Metronomic chemotherapy: bridging theory to clinical application in canine and feline oncology

Veterinary oncology has experienced significant evolution over the last few decades, with chemotherapy being currently applied to several neoplasms with therapeutic success. Traditionally, chemotherapy protocols are based on classic cytostatic drugs under the concept of maximum tolerated dose (MTD), which has been associated with a greater risk of toxicity and resistance. Thus, new therapeutic alternatives have emerged, such as metronomic chemotherapy (MC), introducing a new paradigm in cancer treatment. MC consists of administering low doses of chemotherapy drugs continuously over a long period of time, modulating the tumour microenvironment (TME) due to the combination of cytotoxic, antiangiogenic and immunomodulatory effects. This multi-targeted therapy has been described as a treatment option in several canine and feline cancers since 2007, with positive results already published in the literature, particularly in mammary carcinomas and soft tissue sarcomas in dogs. The aim of this review article is to describe the current knowledge about the use of MC in small animal oncology, with emphasis on its mechanisms of action, the most commonly used drugs and clinical outcome.

Optimizing cancer therapy: a review of the multifaceted effects of metronomic chemotherapy

Metronomic chemotherapy (MCT), characterized by the continuous administration of chemotherapeutics at a lower dose without prolonged drug-free periods, has garnered significant attention over the last 2 decades. Extensive evidence from both pre-clinical and clinical settings indicates that MCT induces distinct biological effects than the standard Maximum Tolerated Dose (MTD) chemotherapy. The low toxicity profile, reduced likelihood of inducing acquired therapeutic resistance, and low cost of MCT render it an attractive chemotherapeutic regimen option. One of the most prominent aspects of MCT is its anti-angiogenesis effects. It has been shown to stimulate the expression of anti-angiogenic molecules, thereby inhibiting angiogenesis. In addition, MCT has been shown to decrease the regulatory T-cell population and promote anti-tumor immune response through inducing dendritic cell maturation and increasing the number of cytotoxic T-cells. Combination therapies utilizing MCT along with oncolytic virotherapy, radiotherapy or other chemotherapeutic regimens have been studied extensively. This review provides an overview of the current status of MCT research and the established mechanisms of action of MCT treatment and also offers insights into potential avenues of development for MCT in the future.

A randomized phase II study of metronomic cyclophosphamide and methotrexate (CM) with or without bevacizumab in patients with advanced breast cancer

PURPOSE

Metronomic chemotherapy has the potential to offer tumor control with reduced toxicity when compared to standard dose chemotherapy in patients with metastatic breast cancer. As metronomic chemotherapy may target the tumor microvasculature, it has the potential for synergistic effects with antiangiogenic agents such as the VEGF-A inhibitor bevacizumab.

METHODS

In this randomized phase II study, patients with metastatic breast cancer were randomized to receive metronomic oral cyclophosphamide and methotrexate (CM) combined with bevacizumab (Arm A) or CM alone (Arm B). The primary endpoint was objective response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), and safety and tolerability.

RESULTS

A total of 55 patients were enrolled, with 34 patients treated on Arm A and 21 patients treated on Arm B. The ORR was modestly higher in Arm A (26%) than in Arm B (10%); neither met the 40% cutoff for further clinical evaluation. The median time to progression (TTP) was 5.52 months (3.22-13.6) on Arm A and 1.82 months (1.54-6.70) on Arm B (log-rank p = 0.008). The median OS was 29.6 months (17.2-NA) on Arm A and 16.2 months (15.7-NA) on Arm B (log-rank p = 0.7). Common all-grade adverse events in both arms included nausea, fatigue, and elevated AST.

CONCLUSION

The combination of metronomic CM with bevacizumab significantly improved PFS over CM alone, although there was no significant difference in OS. Oral metronomic chemotherapy alone has limited activity in advanced breast cancer.

CLINICALTRIALS

gov Identifier: NCT00083031. Date of Registration: May 17, 2004.

Discovery of potent pyrrolo-pyrimidine and purine HDAC inhibitors for the treatment of advanced prostate cancer

The development of drugs for the treatment of advanced prostate cancer (PCA) remains a challenging task. In this study we have designed, synthesized and tested twenty-nine novel HDAC inhibitors based on three different zinc binding groups (trifluoromethyloxadiazole, hydroxamic acid, and 2-mercaptoacetamide). These warheads were conveniently tethered to variously substituted phenyl linkers and decorated with differently substituted pyrrolo-pyrimidine and purine cap groups. Remarkably, most of the compounds showed nanomolar inhibitory activity against HDAC6. To provide structural insights into the Structure-Activity Relationships (SAR) of the investigated compounds, docking of representative inhibitors and molecular dynamics of HDAC6-inhibitor complexes were performed. Compounds of the trifluoromethyloxadiazole and hydroxamic acid series exhibited promising anti-proliferative activities, HDAC6 targeting in PCA cells, and in vitro tumor selectivity. Representative compounds of the two series were tested for solubility, cell permeability and metabolic stability, demonstrating favorable in vitro drug-like properties. The more interesting compounds were subjected to migration assays, which revealed that compound 13 and, to a lesser extent, compound 15 inhibited the invasive behaviour of androgen-sensitive and -insensitive advanced prostate cancer cells. Compound 13 was profiled against all HDACs and found to inhibit all members of class II HDACs (except for HDAC10) and to be selective with respect to class I and class IV HDACs. Overall, compound 13 combines potent inhibitory activity and class II selectivity with favorable drug-like properties, an excellent anti-proliferative activity and marked anti-migration properties on PCA cells, making it an excellent lead candidate for further optimization.

Metronomic Chemotherapy: Anti-Tumor Pathways and Combination with Immune Checkpoint Inhibitors

Increasing evidence pinpoints metronomic chemotherapy, a frequent and low dose drug administration with no prolonged drug-free intervals, as a potential tool to fight certain types of cancers. The primary identified targets of metronomic chemotherapy were the tumor endothelial cells involved in angiogenesis. After this, metronomic chemotherapy has been shown to efficiently target the heterogeneous population of tumor cells and, more importantly, elicit the innate and adaptive immune system reverting the "cold" to "hot" tumor immunologic phenotype. Although metronomic chemotherapy is primarily used in the context of a palliative setting, with the development of new immunotherapeutic drugs, a synergistic therapeutic role of the combined metronomic chemotherapy and immune checkpoint inhibitors has emerged at both the preclinical and clinical levels. However, some aspects, such as the dose and the most effective scheduling, still remain unknown and need further investigation. Here, we summarize what is currently known of the underlying anti-tumor effects of the metronomic chemotherapy, the importance of the optimal therapeutic dose and time-exposure, and the potential therapeutic effect of the combined administration of metronomic chemotherapy with checkpoint inhibitors in preclinical and clinical settings.

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

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

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

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

A Mechanistic Review of Methotrexate and Celecoxib as a Potential Metronomic Chemotherapy for Oral Squamous Cell Carcinoma

The combination of low-dose methotrexate and celecoxib as metronomic chemotherapy (MCT) is a novel therapy, believed to act by modulating the immune response, inhibiting angiogenesis and its cytotoxic action, though the exact mechanism of action is unclear. Clinically, MCT was found to be very effective in delaying tumor progression in patients with head and neck squamous cell carcinoma in both curative and palliative settings. This review was aimed to give a brief insight into the mechanism of action and potential molecular alterations of MCT in the treatment of oral cancers taking into consideration the various in vivo and in vitro studies.

Nanoplatform for the Delivery of Topotecan in the Cancer Milieu: An Appraisal of its Therapeutic Efficacy

Chemotherapy has been the predominant treatment modality for cancer patients, but its overall performance is still modest. Difficulty in penetration of tumor tissues, a toxic profile in high doses, multidrug resistance in an array of tumor types, and the differential architecture of tumor cells as they grow are some of the bottlenecks associated with the clinical usage of chemotherapeutics. Recent advances in tumor biology understanding and the emergence of novel targeted drug delivery tools leveraging various nanosystems offer hope for developing effective cancer treatments. Topotecan is a topoisomerase I inhibitor that stabilizes the transient TOPO I-DNA cleavable complex, leading to single-stranded breaks in DNA. Due to its novel mechanism of action, TOPO is reported to be active against various carcinomas, namely small cell lung cancer, cervical cancer, breast cancer, and ovarian cancer. Issues of cross-resistance with numerous drugs, rapid conversion to its inactive form in biological systems, appended adverse effects, and higher water solubility limit its therapeutic efficacy in clinical settings. Topotecan nanoformulations offer several benefits for enhancing the therapeutic action of this significant class of chemotherapeutics. The likelihood that the target cancer cells will be exposed to the chemotherapeutic drug while in the drug-sensitive s-phase is increased due to the slow and sustained release of the chemotherapeutic, which could provide for a sustained duration of exposure of the target cancer cells to the bioavailable drug and result in the desired therapeutic outcome. This article explores nanoenabled active and passive targeting strategies and combinatorial therapy employing topotecan to ameliorate various cancers, along with a glimpse of the clinical studies utilizing the said molecule.

Programmed Cell Death-Ligand 1 in Head and Neck Squamous Cell Carcinoma: Molecular Insights, Preclinical and Clinical Data, and Therapies

Aberrant expression of the programmed cell death protein ligand 1 (PD-L1) constitutes one of the main immune evasion mechanisms of cancer cells. The approval of drugs against the PD-1-PD-L1 axis has given new impetus to the chemo-therapy of many malignancies. We performed a literature review from 1992 to August 2022, summarizing evidence regarding molecular structures, physiological and pathological roles, mechanisms of PD-L1 overexpression, and immunotherapy evasion. Furthermore, we summarized the studies concerning head and neck squamous cell carcinomas (HNSCC) immunotherapy and the prospects for improving the associated outcomes, such as identifying treatment response biomarkers, new pharmacological combinations, and new molecules. PD-L1 overexpression can occur via four mechanisms: genetic modifications; inflammatory signaling; oncogenic pathways; microRNA or protein-level regulation. Four molecular mechanisms of resistance to immunotherapy have been identified: tumor cell adaptation; changes in T-cell function or proliferation; alterations of the tumor microenvironment; alternative immunological checkpoints. Immunotherapy was indeed shown to be superior to traditional chemotherapy in locally advanced/recurrent/metastatic HNSCC treatments.

Co-targeting triple-negative breast cancer cells and endothelial cells by metronomic chemotherapy inhibits cell regrowth and migration via downregulation of the FAK/VEGFR2/VEGF axis and autophagy/apoptosis activation

High-dose standard-of-care chemotherapy is the only option for triple-negative breast cancer (TNBC) patients, which eventually die due to metastatic tumors. Recently, metronomic chemotherapy (mCHT) showed advantages in treating TNBCs leading us to investigate the anti-metastatic and anti-angiogenic potential of metronomic 5-Fluorouracil plus Vinorelbine (5-FU+VNR) on endothelial cells (ECs) and TNBCs in comparison to standard treatment (STD). We found that 10-fold lower doses of 5-FU+VNR given mCHT vs. STD inhibits cell proliferation and survival of ECs and TNBC cells. Both schedules strongly affect ECs migration and invasion, but in TNBC cells mCHT is significantly more effective than STD in impairing cell migration and invasion. The two treatments disrupt FAK/VEGFR/VEGF signaling in both ECs and TNBC cells. mCHT, and to a much lesser extent STD treatment, induces apoptosis in ECs, whereas it switches the route of cell death from apoptosis (as induced by STD) to autophagy in TNBC cells. mCHT-treated TNBCs-derived conditioned medium also strongly affects ECs' migration, modulates different angiogenesis-associated proteins, and hampers angiogenesis in matrix sponge in vivo. In conclusion, mCHT administration of 5-FU+VNR is more effective than STD schedule in controlling cell proliferation/survival and migration/invasion of both ECs and TNBC cells and has a strong anti-angiogenic effect. Our data suggest that the stabilization of tumor growth observed in TNBC patients treated with mCHT therapy schedule is likely due not only to direct cytotoxic effects but also to anti-metastatic and anti-angiogenic effects.

Assessing chemotherapy dosing strategies in a spatial cell culture model

Predicting patient responses to chemotherapy regimens is a major challenge in cancer treatment. Experimental model systems coupled with quantitative mathematical models to calculate optimal dose and frequency of drugs can enable improved chemotherapy regimens. Here we developed a simple approach to track two-dimensional cell colonies composed of chemo-sensitive and resistant cell populations via fluorescence microscopy and coupled this to computational model predictions. Specifically, we first developed multiple 4T1 breast cancer cell lines resistant to varying concentrations of doxorubicin, and demonstrated how heterogeneous populations expand in a two-dimensional colony. We subjected cell populations to varied dose and frequency of chemotherapy and measured colony growth. We then built a mathematical model to describe the dynamics of both chemosensitive and chemoresistant populations, where we determined which number of doses can produce the smallest tumor size based on parameters in the system. Finally, using an in vitro model we demonstrated multiple doses can decrease overall colony growth as compared to a single dose at the same total dose. In the future, this system can be adapted to optimize dosing strategies in the setting of heterogeneous cell types or patient derived cells with varied chemoresistance.

Longitudinal examination of perfusion and angiogenesis markers in primary colorectal tumors shows distinct signatures for metronomic and maximum-tolerated dose strategies

Metronomic chemotherapy (MET) has been developed to address the shortcomings of maximum-tolerated chemotherapy (MTD) in regard to toxicity and development of resistance mechanisms in the tumor. In colorectal cancer (CRC), MET is a promising novel strategy to treat locally advanced malignancies when used as neoadjuvant chemotherapy (NAC). However, so far there are no preclinical studies to assess the impact of MET NAC in CRC to assess the benefits and challenges of this approach. Here, we used a primary model of CRC (via azoxymethane) to analyze longitudinal changes in angiogenesis in primary tumors under MET and MTD NAC using a combination of diffuse reflectance spectroscopy and mRNA expression (via qPCR). Our results show that MET and MTD NAC lead to increased mean tissue oxygen saturation (8% and 5%, respectively) and oxyhemoglobin (15% and 10%) between weeks 2 and 5 of NAC, and that such increases are caused by distinct molecular signatures in the angiogenic program. Specifically, we find that in the MET group there is a sustained increase in Hif-1a, Aldoa, and Pgk1 expression, suggesting upregulated glycolysis, whereas MTD NAC causes a significant reduction in the expression of the aforementioned genes and of Vegf, leading to vascular remodeling in MTD-treated tumors. Taken together, this study demonstrates the ability of combined optical and molecular methodologies to provide a holistic picture of tumor response to therapy in CRC in a minimally invasive manner.

All-Oral Low-Dose Chemotherapy TEPIP is Effective and Well-Tolerated in Relapsed/Refractory Patients With Aggressive B-Cell Lymphoma

Purpose

Treatment options in patients (pts.) with advanced relapsed and refractory aggressive B-cell lymphoma are limited. Palliative all-oral chemotherapy regimens reduce in-patient visits and contribute to quality of life. The all-oral low-dose chemotherapy regimen TEPIP comprises the conventional chemotherapy agents trofosfamide, etoposide, procarbazine, idarubicin and prednisolone.

Methods

Safety and efficacy of TEPIP was evaluated in an observational retrospective, single-center study at the University Medical Center Regensburg between 2010 and 2020. Treatment with TEPIP was applied for 7 or 10 days during a 28-days period. In a subgroup of fit and therapy-motivated pts. rituximab was added. End points were overall survival (OS) and progression free survival (PFS). Adverse events ≥ CTCAE grade III were reported.

Results

35 highly pre-treated pts. with aggressive B-cell lymphoma were enrolled. Median age at TEPIP start was 67 years and 85% of pts. received TEPIP as ≥ third treatment line. Overall response rate (ORR) was 23% (CR 17%). Pts. benefited from additional rituximab administration (ORR 67%) and a lower number of pre-treatments (ORR 41%). The OS was 3.3 months (m) with a 1y-OS of 25.7% and the PFS amounted to 1.3 m with a 1y-PFS of 8.8%. OS and PFS were significantly prolonged in pts. that responded to treatment or additionally received rituximab. Adverse events were mainly hematological and occurred in 49% of pts.

Conclusion

TEPIP was well-tolerated and induced respectable response in a difficult-to-treat patient cohort. In particular, the all-oral administration enables out-patient use with palliative intent.

Hydrogels for localized chemotherapy of liver cancer: a possible strategy for improved and safe liver cancer treatment

The systemic drug has historically been preferred for the treatment of the majority of pathological conditions, particularly liver cancer. Indeed, this mode of treatment is associated with adverse reactions, toxicity, off-target accumulation, and rapid hepatic and renal clearance. Numerous efforts have been made to design systemic therapeutic carriers to improve retention while decreasing side effects and clearance. Following systemic medication, local administration of therapeutic agents allows for higher 'effective' doses with fewer side effects, kidney accumulation, and clearance. Hydrogels are highly biocompatible and can be used for both imaging and therapy. Hydrogel-based drug delivery approach has fewer side effects than traditional chemotherapy and can deliver drugs to tumors for a longer time. The chemical and physical flexibility of hydrogels can be used to achieve disease-induced in situ accumulation as well as subsequent drug release and hydrogel-programmed degradation. Moreover, they can act as a biocompatible depot for localized chemotherapy when stimuli-responsive carriers are administrated. Herein, we summarize the design strategies of various hydrogels used for localized chemotherapy of liver cancer and their delivery routes, as well as recent research on smart hydrogels.

Hyaluronic Acid Nanoparticles for Immunogenic Chemotherapy of Leukemia and T-Cell Lymphoma

Ratiometric delivery of combination chemotherapy can achieve therapeutic efficacy based on synergistic interactions between drugs. It is critical to design such combinations with drugs that complement each other and reduce cancer growth through multiple mechanisms. Using hyaluronic acid (HA) as a carrier, two chemotherapeutic agents-doxorubicin (DOX) and camptothecin (CPT)-were incorporated and tested for their synergistic potency against a broad panel of blood-cancer cell lines. The pair also demonstrated the ability to achieve immunogenic cell death by increasing the surface exposure levels of Calreticulin, thereby highlighting its ability to induce apoptosis via an alternate pathway. Global proteomic profiling of cancer cells treated with HA-DOX-CPT identified pathways that could potentially predict patient sensitivity to HA-DOX-CPT. This lays the foundation for further exploration of integrating drug delivery and proteomics in personalized immunogenic chemotherapy.

Angiogenesis and chemotherapy resistance: optimizing chemotherapy scheduling using mathematical modeling

Chemotherapy remains a widely used cancer treatment. Acquired drug resistance may greatly reduce the efficacy of treatment and means to overcome it are a topic of active discussion among researchers. One of the proposed solutions is to shift the therapeutic paradigm from complete eradication of cancer to maintenance, i.e., to treat it as a chronic disease. A concept of metronomic therapy (low chemotherapy doses applied continuously) emerged in early 2000s and was henceforth shown to offer a number of benefits, including targeting endothelial cells and reducing acquired drug resistance. Using mathematical modeling and optimal control techniques, we investigate the hypothesis that lower doses of chemotherapy are beneficial for patients. Our analysis of a mathematical model of tumor growth under angiogenic signaling proposed by Hahnfeldt et al. adapted to heterogeneous tumors treated by combined anti-angiogenic agent and chemotherapy offers insights into the effects of metronomic therapy. Firstly, assuming constant long-term drug delivery, the model suggests that the longest survival time is achieved for intermediate drug doses. Secondly, by formalizing the notion of the therapeutic target being maintenance rather than eradication, we show that in the short term, optimal chemotherapy scheduling consists mainly of a drug applied at a low dose. In conclusion, we suggest that metronomic therapy is an attractive alternative to maximum tolerated dose therapies to be investigated in experimental settings and clinical trials.

Low Cost, Low Dose, Oral, Neoadjuvant Chemotherapy Protocol in Locally Advanced Borderline Oral Cancers-Feasibility Study

A vast majority of oral cancer patients in developing countries present in an advanced stage with borderline resectable/inoperable stage to busy resource-constrained tertiary cancer centers. Conventional chemotherapy protocols are associated with issues like toxicity, tolerance, cost, and compliance. The present study was conducted to assess the feasibility of low-cost home-based chemotherapy options. Single-arm feasibility study was done in borderline resectable/inoperable oral cancer patients. Home-based oral neoadjuvant chemotherapy consisting of oral methotrexate 15 mg/m² once a week and oral celecoxib 200 mg twice daily for 8 weeks was used. RECIST Criteria 1.1 was used to assess response to therapy. The study included 60 patients. The mean age was 51.98 years with male predominance (80%). Fifty-five patients adhered to the treatment; the compliance rate is 91.60%. Affordability (Rs 700 per month) and tolerance to therapy was 100%, and no grade III or IV toxicity was seen. Overall, 18 patients had stable disease (32.73%), partial response was seen in 15 patients (27.27%), and the disease progressed in 22 patients (40%). At the end of 8 weeks, 26 (43.3%) patients were deemed resectable. Neoadjuvant low cost, home-based metronomic chemotherapy using oral methotrexate and celecoxib seems to be a viable option in managing advanced oral cancer in resource-constrained setups.

Oral metronomic chemotherapy is a cost effective alternative to pazopanib in advanced soft tissue sarcoma

INTRODUCTION

Soft tissue sarcoma(STS) is a rare and heterogeneous group of disorders with dismal outcomes in metastatic setting. Pazopanib and oral metronomic chemotherapy (OMT) have been evaluated as therapeutic options in this cohort.

MATERIALS AND METHODS

We conducted a retrospective, single center study evaluating 45 patients with unresectable and/or metastatic STS, who received pazopanib or oral metronomic regimen as per instituitonal protocol between January 2013 and December 2019. An informal cost minimisation analysis was conducted for both OMT and pazopanib arms, considering equivalent outcomes for both (PFS and OS).

RESULTS

Median PFS in OMT and Pazopanib groups was 4.13 months and 3.53 months,respectively (HR1.31, 95% CI:0.68-2.51, p = 0.41) Only one patient in the OMT group achieved an objective response (partial response) and no objective response was noted in the pazopanib group. The incidence of grade III/IVtoxicities was higher with pazopanib than with OMT (p = 0.08). There were no toxicity related deaths noted in either arm.

CONCLUSIONS

Our study demonstrates that OMT have a similar progression free survival (PFS) and overall survival (OS) in metastatic STS. This study raises the possibility that OMT might be an equally efficacious and less toxic alternative to pazopanib, without compromising survival outcome especially in LMIC.

Metronomic treatment of vinorelbine with oral capecitabine is tolerable in the randomized Phase 2 study XeNa including patients with HER2 non-amplified metastatic breast cancer

BACKGROUND

Metronomic treatment is hypothesized to be less toxic and more effective as compared to standard maximal tolerable dosing treatment in metastatic cancer disease.

MATERIAL AND METHODS

We tested the metronomic treatment principle with vinorelbine in a randomized phase 2 setting combined with standard capecitabine treatment in the XeNa trial with Clinical Trials.gov identifier number: NCT0141771. 120 patients with disseminated HER2 non-amplified breast cancer were included. Randomization was between Arm A: vinorelbine 60 mg/m² day 1 + day 8 in the first cycle followed by 80 mg/m² day 1 + day 8 in the following cycles or Arm B: vinorelbine 50 mg three times a week. Capecitabine 1000 mg/m² twice a day for days 1-14 was administered in both arms.

RESULTS

The treatment was generally well-tolerated. The response rate (RR) was 24% (arm A) versus 29% (arm B) (p = .67). The clinical benefit rate (CBR) 46.8% (arm A) versus 51.7% (arm B) (p = .72). We found a median progression-free survival (PFS) of 7.1 months (95% confidence interval [CI] 3.9-10.3) in arm A and 6.3 months (95% CI 4.1-8.5) in arm B (p = .25) whereas median overall survival (OS) was 23.3 months (95% CI 20.2-26.4) in arm A and 22.3 months (95% CI 14.3-30.3) in arm B (p = .76).

CONCLUSIONS

We confirmed that the combination of vinorelbine and capecitabine was well tolerated. Metronomic treatment can be used with acceptable adverse events (AEs), but we did not find significant difference in the effect compared to the standard treatment.

Tumor microenvironment: an evil nexus promoting aggressive head and neck squamous cell carcinoma and avenue for targeted therapy

Head and neck squamous cell carcinoma (HNSCC) is a very aggressive disease with a poor prognosis for advanced-stage tumors. Recent clinical, genomic, and cellular studies have revealed the highly heterogeneous and immunosuppressive nature of HNSCC. Despite significant advances in multimodal therapeutic interventions, failure to cure and recurrence are common and account for most deaths. It is becoming increasingly apparent that tumor microenvironment (TME) plays a critical role in HNSCC tumorigenesis, promotes the evolution of aggressive tumors and resistance to therapy, and thereby adversely affects the prognosis. A complete understanding of the TME factors, together with the highly complex tumor-stromal interactions, can lead to new therapeutic interventions in HNSCC. Interestingly, different molecular and immune landscapes between HPV^+ve and HPV^-ve (human papillomavirus) HNSCC tumors offer new opportunities for developing individualized, targeted chemoimmunotherapy (CIT) regimen. This review highlights the current understanding of the complexity between HPV^+ve and HPV^-ve HNSCC TME and various tumor-stromal cross-talk modulating processes, including epithelial-mesenchymal transition (EMT), anoikis resistance, angiogenesis, immune surveillance, metastatic niche, therapeutic resistance, and development of an aggressive tumor phenotype. Furthermore, we summarize the recent developments and the rationale behind CIT strategies and their clinical applications in HPV^+ve and HPV^-ve HNSCC.

Improving Convergence in Therapy Scheduling Optimization: A Simulation Study

The infusion times and drug quantities are two primary variables to optimize when designing a therapeutic schedule. In this work, we test and analyze several extensions to the gradient descent equations in an optimal control algorithm conceived for therapy scheduling optimization. The goal is to provide insights into the best strategies to follow in terms of convergence speed when implementing our method in models for dendritic cell immunotherapy. The method gives a pulsed-like control that models a series of bolus injections and aims to minimize a cost a function, which minimizes tumor size and to keep the tumor under a threshold. Additionally, we introduce a stochastic iteration step in the algorithm, which serves to reduce the number of gradient computations, similar to a stochastic gradient descent scheme in machine learning. Finally, we employ the algorithm to two therapy schedule optimization problems in dendritic cell immunotherapy and contrast our method’s stochastic and non-stochastic optimizations.

Improvements in the Oral Absorption and Anticancer Efficacy of an Oxaliplatin-Loaded Solid Formulation: Pharmacokinetic Properties in Rats and Nonhuman Primates and the Effects of Oral Metronomic Dosing on Colorectal Cancer

Objective

The anticancer efficacy of orally administered chemotherapeutics is often constrained by low intestinal membrane permeability and oral bioavailability. In this context, we designed a solid oral formulation of oxaliplatin (OP), a third-generation cisplatin analog, to improve oral bioavailability and investigate its application in metronomic chemotherapy.

Methods

An ion-pairing complex of OP with a permeation enhancer, N^α-deoxycholyl-l-lysyl-methylester (DLM), was successfully prepared and then mixed with dispersing agents (including poloxamer 188 and Labrasol) to form the solid, amorphous oral formulation OP/DLM (OP/DLM-SF; hereafter, ODSF).

Results

The optimized powder formulation was sized in the nanoscale range (133±1.47 nm). The effective permeability of OP increased by 12.4-fold after ionic complex formation with DLM and was further increased by 24.0-fold after incorporation into ODSF. ODSF exhibited respective increases of 128% and 1010% in apparent permeability across a Caco-2 monolayer, compared to OP/DLM and OP. Furthermore, inhibition of bile acid transporters by actinomycin D and caveola-mediated uptake by brefeldin in Caco-2 cell monolayers reduced the apparent permeability values of ODSF by 58.4% and 51.1%, respectively, suggesting predominant roles for bile acid transporters and caveola-mediated transport in intestinal absorption of ODSF. In addition, macropinocytosis and paracellular and transcellular passive transport significantly influenced the intestinal permeation of ODSF. The oral bioavailabilities of ODSF in rats and monkeys were 68.2% and 277% higher, respectively, than the oral bioavailability of free OP. In vivo analyses of anticancer efficacy in CT26 and HCT116 cell-bearing mice treated with ODSF demonstrated significant suppression of tumor growth, with respective maximal tumor volume reductions of 7.77-fold and 4.07-fold, compared to controls.

Conclusion

ODSF exhibits therapeutic potential, constituting an effective delivery system that increases oral bioavailability, with applications to metronomic chemotherapy.

Antibody-drug conjugates, cancer immunotherapy, and metronomic chemotherapy as novel approaches in cancer management

Treatment of cancer is a major challenge even though the pathophysiology is becoming clearer with time. A number of new chemical entities are developed to target cancer growth inhibition, but the targeted delivery of these products still needs novel research. This is of utmost importance not only for higher efficacy but also for a reduction in systemic toxicity and cost of treatment. Although multiple novel targets and molecules are being researched, most of them could not pass the regulatory approval process, due to low benefit-risk ratio and lack of target specificity. Failure of a majority of these drugs was in part due to their superiority claimed via surrogate markers. Despite these, currently, more than 100 chemotherapeutic agents are in practice. This review paper discusses in detail the molecular basis, drug discovery, and pros and cons over conventional treatment approaches of three novel approaches in cancer therapy, i.e., (i) antibody-drug conjugates, (ii) cancer immunotherapy, and (iii) metronomic chemotherapy. All the drugs developed using these three novel approaches were compared against the established treatment regimens in clinical trials with clinical end points, such as overall survival, progression-free survival, and quality of life.

Eco-oncology: Applying ecological principles to understand and manage cancer

Cancer is a disease of single cells that expresses itself at the population level. The striking similarities between initiation and growth of tumors and dynamics of biological populations, and between metastasis and ecological invasion and community dynamics suggest that oncology can benefit from an ecological perspective to improve our understanding of cancer biology. Tumors can be viewed as complex, adaptive, and evolving systems as they are spatially and temporally heterogeneous, continually interacting with each other and with the microenvironment and evolving to increase the fitness of the cancer cells. We argue that an eco-evolutionary perspective is essential to understand cancer biology better. Furthermore, we suggest that ecologically informed therapeutic approaches that combine standard of care treatments with strategies aimed at decreasing the evolutionary potential and fitness of neoplastic cells, such as disrupting cell-to-cell communication and cooperation, and preventing successful colonization of distant organs by migrating cancer cells, may be effective in managing cancer as a chronic condition.

Outcome of Canine Multicentric Lymphoma after Single or Divided Treatment with Cyclophosphamide in Multidrug Chemotherapy

Cyclophosphamide is commonly used in combination chemotherapy to treat dogs with lymphoma. The metabolite of cyclophosphamide, acrolein, can irritate urinary bladder and cause sterile hemorrhagic cystitis. Dividing the administration of cyclophosphamide across multiple days may reduce the concentration of this metabolite in urinary bladder and reduce the possibility of cystitis. However, the impact of the therapeutic effect of this modification is not evaluated and compared to traditional single maximum-tolerated dose regimen. Seventy-two dogs with multicentric lymphoma received either bolus doses or divided doses of cyclophosphamide were included in this study. The incidence of hemorrhagic cystitis between 2 cyclophosphamide treatment groups was not significantly different (P = .357). There was no statistical difference in progression-free survival and survival time between 2 groups (P = .267 and P = .346). This modification of cyclophosphamide administration did not reduce the side effect of cystitis or affect remission and survival times in lymphoma dogs.

Multiple low dose therapy as an effective strategy to treat EGFR inhibitor-resistant NSCLC tumours

Resistance to targeted cancer drugs is thought to result from selective pressure exerted by a high drug dose. Partial inhibition of multiple components in the same oncogenic signalling pathway may add up to complete pathway inhibition, while decreasing the selective pressure on each component to acquire a resistance mutation. We report here testing of this Multiple Low Dose (MLD) therapy model in EGFR mutant NSCLC. We show that as little as 20% of the individual effective drug doses is sufficient to completely block MAPK signalling and proliferation when used in 3D (RAF + MEK + ERK) or 4D (EGFR + RAF + MEK + ERK) inhibitor combinations. Importantly, EGFR mutant NSCLC cells treated with MLD therapy do not develop resistance. Using several animal models, we find durable responses to MLD therapy without associated toxicity. Our data support the notion that MLD therapy could deliver clinical benefit, even for those having acquired resistance to third generation EGFR inhibitor therapy.

A drug used at the maximum tolerated dose can exert a strong selective pressure on cancer cells leading to resistance. In this study, the authors demonstrate the efficacy of using low dose of multiple drugs for preventing and treating resistance to EGFR tyrosine kinase inhibitors in NSCLC cells.

Optimal Control Theory for Personalized Therapeutic Regimens in Oncology: Background, History, Challenges, and Opportunities

Optimal control theory is branch of mathematics that aims to optimize a solution to a dynamical system. While the concept of using optimal control theory to improve treatment regimens in oncology is not novel, many of the early applications of this mathematical technique were not designed to work with routinely available data or produce results that can eventually be translated to the clinical setting. The purpose of this review is to discuss clinically relevant considerations for formulating and solving optimal control problems for treating cancer patients. Our review focuses on two of the most widely used cancer treatments, radiation therapy and systemic therapy, as they naturally lend themselves to optimal control theory as a means to personalize therapeutic plans in a rigorous fashion. To provide context for optimal control theory to address either of these two modalities, we first discuss the major limitations and difficulties oncologists face when considering alternate regimens for their patients. We then provide a brief introduction to optimal control theory before formulating the optimal control problem in the context of radiation and systemic therapy. We also summarize examples from the literature that illustrate these concepts. Finally, we present both challenges and opportunities for dramatically improving patient outcomes via the integration of clinically relevant, patient-specific, mathematical models and optimal control theory.

Modeling Neoadjuvant chemotherapy resistance in vitro increased NRP-1 and HER2 expression and converted MCF7 breast cancer subtype

BACKGROUND AND PURPOSE

Patients with locally advanced breast cancer usually receive third-generation neoadjuvant chemotherapy (NAC). Although NAC treatment improved the overall survival, patients' response varies, some acquire resistance and others exhibit a conversion in their breast cancer molecular subtype. We aimed to identify the molecular changes involved in NAC resistance attempting to find new therapeutic targets in different breast cancer subtypes.

EXPERIMENTAL APPROACH

We modelled NAC treatments used in clinical practice and generated resistant cell lines in vitro. The resistant cells were generated by consecutive treatment with four cycles of doxorubicin (adriamycin)/cyclophosphamide (4xAC) followed by an additional four cycles of paclitaxel (4xAC + 4xPAC).

KEY RESULTS

Our data revealed distinct mechanisms of resistance depending on breast cancer subtype and drugs used. MDA-MB-231 cells resistant to 4xAC + 4xPAC activated neuropilin-1/TNC/integrin β3/FAK/NF-κBp65 axis and displayed a decrease in breast cancer resistance protein (BCRP/ABCB2). However, MCF7 cells resistant to 4xAC treatments induced HER2 expression, which converted MCF7 subtype from luminal A to luminal B HER2 type, up-regulated neuropilin-1, oestrogen receptor-α, and EGFR, and activated PI3K/Akt/NF-κBp65 axis. However, MCF7 cells resistant to 4xAC + 4xPAC exhibited down-regulation of the survival axis and up-regulated BCRP/ABCG2. Co-immunoprecipitation demonstrated a novel interaction between HER2 and neuropilin-1 driving the resistance features.

CONCLUSIONS AND IMPLICATIONS

The concurrent increase in neuropilin-1 and HER2 upon resistance and the inverse relationship between neuropilin-1 and BCRP/ABCG2 suggest that, in addition to HER2, neuropilin-1 status should be assessed in patients undergoing NAC, and as a potential drug target for refractory breast cancer.

Low Dose Cyclophosphamide Modulates Tumor Microenvironment by TGF-β Signaling Pathway

The tumor microenvironment has been recently recognized as a critical contributor to cancer progression and anticancer therapy-resistance. Cyclophosphamide (CTX) is a cytotoxic agent commonly used in clinics for the treatment of cancer. Previous reports demonstrated that CTX given at low continuous doses, known as metronomic schedule, mainly targets endothelial cells and circulating Tregs with unknown mechanisms. Here, we investigated the antitumor activity of two different metronomic schedules of CTX along with their corresponding MTD regimen and further explored their effect on immune function and tumor microenvironment. Toxicity evaluation was monitored by overall survival rate, weight loss, and histopathological analysis. A nude mouse model of Lewis lung cancer was established to assess the anti-metastatic effects of CTX in vivo. CD4⁺, CD8⁺, and CD4⁺CD25⁺FoxP3 T cells were selected by flow cytometry analysis. Low and continuous administration of CTX was able to restore immune function via increase of CD4⁺/CD8⁺ T cells and depletion of T regulatory cells, not only in circulatory and splenic compartments, but also at the tumor site. Low-dose CTX also reduced myofibroblasts, accompanied with an increased level of E-cadherin and low N-cadherin, both in the primary tumor and lung through the TGF-β pathway by the downregulated expression of TGF-β receptor 2. Our data may indicate that several other molecular mechanisms of CTX for tumor may be involved in metronomic chemotherapy, besides targeting angiogenesis and regulatory T cells.

Prolonged administration of low-dose cytarabine and thioguanine in elderly patients with acute myeloid leukaemia (AML) achieves high complete remission rates and prolonged survival

The prognosis of AML in elderly patients is poor and research into novel therapeutic approaches is urgently needed. This study examined the use of low-dose chemotherapy with cytarabine and thioguanine administered in repetitive cycles in 62 elderly patients with newly diagnosed or relapsed/refractory AML. The overall response rate was 58% in the total cohort. Response rates (CR/CRi) were significantly higher in patients with newly diagnosed AML (74%) compared to patients with relapsed/refractory disease (25%, p = .0004). Kaplan-Meier estimate of overall survival was 289 days (95% CI; 183-395 days) with a relapse rate of 65.7%. The induction mortality rate was 16.1% with treatment successfully undertaken in the outpatient setting. Similar clinical outcomes were observed in a retrospective analysis of a second cohort of 25 AML patients treated at a different site. These results support the use of a sustained low intensity chemotherapy approach as a therapeutic option for elderly patients with AML.

Safety and Activity of Metronomic Temozolomide in Second-Line Treatment of Advanced Neuroendocrine Neoplasms

BACKGROUND

Platinum-based chemotherapy is the mainstay of front-line treatment of patients affected by pluri-metastatic intermediate/high grade NeuroEndocrine Neoplasms (NENs). However, there are no standard second-line treatments at disease progression. Previous clinical experiences have evidenced that temozolomide (TMZ), an oral analog of dacarbazine, is active against NENs at standard doses of 150 to 200 mg/mq per day on days 1 to 5 of a 28-day cycle, even if a significant treatment-related toxicity is reported.

METHODS

Metastatic NENs patients were treated at the ENETS (European NeuroEndocrine Tumor Society) center of excellence of Naples (Italy), from 2014 to 2017 with a second-line alternative metronomic schedule of TMZ, 75 mg/m2 per os "one week on/one week off". Toxicity was graded with NCI-CTC criteria v4.0; objective responses with RECIST v1.1 and performance status (PS) according to ECOG.

RESULTS

Twenty-six consecutive patients were treated. Median age was 65.5 years. The predominant primary organs were pancreas and lung. Grading was G2 in 11 patients, G3 in 15. More than half of patients had a PS 2 (15 vs. 11 with PS 1). The median time-on-temozolomide therapy was 12.2 months (95% CI: 11.4-19.6). No G3/G4 toxicities were registered. Complete response was obtained in 1 patient, partial response in 4, stable disease in 19 (disease control rate: 92.3%), and progressive disease in 2. The median overall survival from TMZ start was 28.3 months. PS improved in 73% of patients.

CONCLUSIONS

Metronomic TMZ is a suitable treatment for G2 and G3 NENs particularly in PS 2 patients. Prospective and larger trials are needed to confirm these results.

The NAME trial: a direct comparison of classical oral Navelbine versus Metronomic Navelbine in metastatic breast cancer

Chemotherapy for metastatic breast cancer (MBC) is in general given in cycles of maximum tolerated doses to potentially maximize the therapeutic outcome. However, when compared with targeted therapies for MBC, conventional and dose intensified chemotherapy has caused only modest survival benefits during the recent decades, often compromising the quality of life considerably. Navelbine is an antineoplastic agent that has shown efficacy in the treatment of a variety of cancer types, including breast cancer. Early clinical trials involving both breast cancer and lung cancer patients suggest that metronomic dosing of Navelbine might be at least as effective as classical administration (once weekly, etc.). The NAME trial compares these two strategies of Navelbine administration in MBC patients.

Rethinking Alkylating(-Like) Agents for Solid Tumor Management

Although old molecules, alkylating agents and platinum derivatives are still widely used in the treatment of various solid tumors. However, systemic toxicity and cellular resistance mechanisms impede their efficacy. Innovative strategies, including local administration, optimization of treatment schedule/dosage, synergistic combinations, and the encapsulation of bioactive molecules in smart, multifunctional drug delivery systems, have shown promising results in potentiating anticancer activity while circumventing such hurdles. Furthermore, questioning of the old paradigm according to which nuclear DNA is the critical target of their anticancer activity has shed light on subcellular alternative and neglected targets that obviously participate in the mediation of cytotoxicity or resistance. Thus, rethinking of the use of these pivotal antineoplastic agents appears critical to improve clinical outcomes in the management of solid tumors.

The Role of Precision Medicine in the Diagnosis and Treatment of Patients with Rare Cancers

Rare cancers pose unique challenges for patients and their physicians arising from a lack of information regarding the best therapeutic options. Very often, a lack of clinical trial data leads physicians to choose treatments based on small case series or case reports. Precision medicine based on genomic analysis of tumors may allow for selection of better treatments with greater efficacy and less toxicity. Physicians are increasingly using genetics to identify patients at high risk for certain cancers to allow for early detection or prophylactic interventions. Genomics can be used to inform prognosis and more accurately establish a diagnosis. Genomic analysis may also expose therapeutic targets for which drugs are currently available and approved for use in other cancers. Notable successes in the treatment of previously refractory cancers have resulted. New more advanced sequencing technologies, tools for interpretation, and an increasing array of targeted drugs offer additional hope, but challenges remain.

High-resolution deconstruction of evolution induced by chemotherapy treatments in breast cancer xenografts

The processes by which tumors evolve are essential to the efficacy of treatment, but quantitative understanding of intratumoral dynamics has been limited. Although intratumoral heterogeneity is common, quantification of evolution is difficult from clinical samples because treatment replicates cannot be performed and because matched serial samples are infrequently available. To circumvent these problems we derived and assayed large sets of human triple-negative breast cancer xenografts and cell cultures from two patients, including 86 xenografts from cyclophosphamide, doxorubicin, cisplatin, docetaxel, or vehicle treatment cohorts as well as 45 related cell cultures. We assayed these samples via exome-seq and/or high-resolution droplet digital PCR, allowing us to distinguish complex therapy-induced selection and drift processes among endogenous cancer subclones with cellularity uncertainty <3%. For one patient, we discovered two predominant subclones that were granularly intermixed in all 48 co-derived xenograft samples. These two subclones exhibited differential chemotherapy sensitivity–when xenografts were treated with cisplatin for 3 weeks, the post-treatment volume change was proportional to the post-treatment ratio of subclones on a xenograft-to-xenograft basis. A subsequent cohort in which xenografts were treated with cisplatin, allowed a drug holiday, then treated a second time continued to exhibit this proportionality. In contrast, xenografts from other treatment cohorts, spatially dissected xenograft fragments, and cell cultures evolved in diverse ways but with substantial population bottlenecks. These results show that ecosystems susceptible to successive retreatment can arise spontaneously in breast cancer in spite of a background of irregular subclonal bottlenecks, and our work provides to our knowledge the first quantification of the population genetics of such a system. Intriguingly, in such an ecosystem the ratio of common subclones is predictive of the state of treatment susceptibility, showing how measurements of subclonal heterogeneity could guide treatment for some patients.