Safety and therapeutic effect of metronomic chemotherapy with cyclophosphamide and celecoxib in advanced breast cancer patients

"Cyclophosphamide and analogues; a matter of dose and schedule for dual anticancer activities"

Cyclophosphamide and ifosfamide are major alkylating agents but their therapeutics uses are limiting by the toxicity due to several toxicities. Indeed conventional chemotherapies are generally used with the maximum tolerated dose. In contrast, metronomic schedule aims to get a minimum dose for efficacy with a good safety. Depending on the dose, their mechanisms of action are different and offer a dual activity: at high dose, cyclophosphamide is mainly used in graft conditioning for its immunosuppressive properties, while at metronomic dose it is used as an immunoactive agent. Currently, at metronomic dose, cyclophosphamide is studied in clinic against various types of cancer, alone or in combination with others anticancer drugs (anti-angiogenic, immune-modulating agents, immune checkpoints blockers, vaccines, radiotherapy, others conventional anticancer agents), as a nth-line or first-line treatment. More than three quarters of clinical studies show promising results, mostly in breast, ovarian and prostate cancers. Taking advantage of the immune system, use dual antitumor action's chemotherapy is clearly a therapeutic strategy that deserves to be confirmed in order to improve the efficacy/toxicity balance of anticancer treatments, and to use CPM or analogues as a standard of care.

Challenges and Opportunities for Celecoxib Repurposing

Drug repositioning, also known as drug repurposing, reprofiling, or rediscovery, is considered to be one of the most promising strategies to accelerate the development of new original drug products. Multiple examples of successful rediscovery or therapeutic switching of old molecules that did not show clinical benefits or safety in initial trials encourage the following of the discovery of new therapeutic pathways for them. This review summarizes the efforts that have been made, mostly over the last decade, to identify new therapeutic targets for celecoxib. To achieve this goal, records gathered in MEDLINE PubMed and Scopus databases along with the registry of clinical trials by the US National Library of Medicine at the U.S. National Institutes of Health were explored. Since celecoxib is a non-steroidal anti-inflammatory drug that represents the class of selective COX-2 inhibitors (coxibs), its clinical potential in metronomic cancer therapy, the treatment of mental disorders, or infectious diseases has been discussed. In the end, the perspective of a formulator, facing various challenges related to unfavorable physicochemical properties of celecoxib upon the development of new oral dosage forms, long-acting injectables, and topical formulations, including the latest trends in the pharmaceutical technology, such as the application of mesoporous carriers, biodegradable microparticles, lipid-based nanosystems, or spanlastics, was presented.

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

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

Selective COX-2 Inhibitors: Road from Success to Controversy and the Quest for Repurposing

The introduction of selective COX-2 inhibitors (so-called ‘coxibs’) has demonstrated tremendous commercial success due to their claimed lower potential of serious gastrointestinal adverse effects than traditional NSAIDs. However, following the repeated questioning on safety concerns, the coxibs ‘controversial me-too’ saga increased substantially, inferring to the risk of cardiovascular complications, subsequently leading to the voluntary withdrawal of coxibs (e.g., rofecoxib and valdecoxib) from the market. For instance, the makers (Pfizer and Merck) had to allegedly settle individual claims of cardiovascular hazards from celecoxib and valdecoxib. Undoubtedly, the lessons drawn from this saga revealed the flaws in drug surveillance and regulation, and taught science to pursue a more integrated translational approach for data acquisition and interpretation, prompting science-based strategies of risk avoidance in order to sustain the value of such drugs, rather than their withdrawal. Looking forward, coxibs are now being studied for repurposing, given their possible implications in the management of a myriad of diseases, including cancer, epilepsy, psychiatric disorders, obesity, Alzheimer’s disease, and so on. This article briefly summarizes the development of COX-2 inhibitors to their market impression, followed by the controversy related to their toxicity. In addition, the events recollected in hindsight (the past lessons), the optimistic step towards drug repurposing (the present), and the potential for forthcoming success (the future) are also discussed.

High ROS Production by Celecoxib and Enhanced Sensitivity for Death Ligand-Induced Apoptosis in Cutaneous SCC Cell Lines

Incidence of cutaneous squamous cell carcinoma (cSCC) and actinic keratosis has increased worldwide, and non-steroidal anti-inflammatory drugs as celecoxib are considered for treatment. We show here strong anti-proliferative effects of celecoxib in four cSCC cell lines, while apoptosis and cell viability largely remained unaffected. Impeded apoptosis was overcome in combinations with agonistic CD95 antibody or TNF-related apoptosis-inducing ligand (TRAIL), resulting in up to 60% apoptosis and almost complete loss of cell viability. Proapoptotic caspase cascades were activated, and apoptosis was suppressed by caspase inhibition. TRAIL receptor (DR5) and proapoptotic Bcl-2 proteins (Puma and Bad) were upregulated, while anti-apoptotic factors (survivin, XIAP, cFLIP, Mcl-1, and Bcl-w) were downregulated. Strongly elevated levels of reactive oxygen species (ROS) turned out as particularly characteristic for celecoxib, appearing already after 2 h. ROS production alone was not sufficient for apoptosis induction but may play a critical role in sensitizing cancer cells for apoptosis and therapy. Thus, the full therapeutic potential of celecoxib may be better used in combinations with death ligands. Furthermore, the immune response against cSCC/AK may be improved by celecoxib, and combinations with checkpoint inhibitors, recently approved for the treatment of cSCC, may be considered.

The role of COX expression in the prognostication of overall survival of canine and feline cancer: A systematic review

Cyclooxygenase (COX) isoforms-1 and -2 have been extensively investigated in cancer. Although COX-2 is the isoform most studied and has been described in several malignancies associated with histologic criteria of malignancy and worse prognosis, COX-1 has also been linked to some forms of cancer. With the present review our aim was to summarize the current state of knowledge and clarify if and in which type of tumours COX-1 and/or COX-2 expression have real prognostic implications. We searched PubMed database for prognostic studies using predefined inclusion criteria in order to ascertain the prognostic value of COX-1 and COX-2 in malignant neoplasia in dogs and cats. Eighteen studies were analysed. COX-2 was shown to be a negative prognostic factor in canine and feline mammary tumours, canine mast cell tumour, canine melanoma, canine osteosarcoma and canine renal cell carcinoma. COX-1 showed a negative prognostic value in feline oral squamous cell carcinoma (SCC). We found high heterogeneity among studies regarding COX immunohistochemical evaluation methodology even in the same type of neoplasia pointing out the need for its standardization at least by tumour type. The available data support the use of COX-2 as a prognostic factor in canine (mammary carcinoma, mast cell tumour, melanoma, osteosarcoma and renal carcinoma) and feline (mammary carcinoma) cancers. For COX-1, its use is advised in feline oral SCC.

Losartan improves the therapeutic effect of metronomic cyclophosphamide in triple negative mammary cancer models

Metronomic chemotherapy refers to the minimum biologically effective doses of a chemotherapy agent given as a continuous regimen without extended rest periods. Drug repurposing is defined as the use of an already known drug for a new medical indication, different from the original one. In oncology the combination of these two therapeutic approaches is called "Metronomics". The aim of this work is to evaluate the therapeutic effect of cyclophosphamide in a metronomic schedule in combination with the repurposed drug losartan in two genetically different mice models of triple negative breast cancer. Our findings showed that adding losartan to metronomic cyclophosphamide significantly improved the therapeutic outcome. In both models the combined treatment increased the mice's survival without sings of toxicity. Moreover, we elucidated some of the mechanisms of action involved, which include a decrease of intratumor hypoxia, stimulation of the immune response and remodeling of the tumor microenvironment. The remarkable therapeutic effect, the lack of toxicity, the low cost of the drugs and its oral administration, strongly suggest its translation to the clinical setting in the near future.

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

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

Celecoxib in Cancer Therapy and Prevention - Review

BACKGROUND AND OBJECTIVES

It is generally accepted that inflammatory cells found in the tumor microenvironment are involved in the neoplastic process, promoting cell proliferation, survival, and migration. Therefore, administering anti-inflammatory medication in cancer therapy seems to be justified. A potential pathway associated with the aforementioned issue is cyclooxygenase-2 inhibition, particularly as the overexpression of this enzyme has been proven to occur in cancer tissues and is also associated with a poor prognosis in several types of human malignancies. Celecoxib, a COX-2 selective inhibitor, has been utilized for over 20 years, particularly as an anti-inflammatory, analgesic and antipyretic medication. However, to date, its antineoplastic properties have not been sufficiently investigated. In recent years, the number of research studies on the antineoplastic effects of celecoxib has increased considerably. The vast majority of publications refers to preclinical studies attempting to elucidate its mechanisms of action. Clinical trials concerning celecoxib have focused primarily on the treatment of cancers of the colon, breast, lung, prostate, stomach, head and neck, as well as premalignant lesions such as familial adenoma polyposis. In this review article authors attempt to summarise the latest research which has elucidated celecoxib use in the treatment and prevention of cancer.

CONCLUSION

Both preclinical and clinical studies have demonstrated promising results of the role of celecoxib in the treatment and prevention of cancer - the best outcome was observed in colon, breast, prostate and head and neck cancers. However, more clinical trials providing real evidence-based clinical advances of celecoxib use are needed.

Metronomic Chemotherapy: A Systematic Review of the Literature and Clinical Experience

Metronomic chemotherapy, continuous and dose-dense administration of chemotherapeutic drugs with lowered doses, is being evaluated for substituting, augmenting, or appending conventional maximum tolerated dose regimens, with preclinical and clinical studies for the past few decades. To date, the principle mechanisms of its action include impeding tumoral angiogenesis and modulation of hosts' immune system, affecting directly tumor cells, their progenitors, and neighboring stromal cells. Its better toxicity profile, lower cost, and easier use are main advantages over conventional therapies. The evidence of metronomic chemotherapy for personalized medicine is growing, starting with unfit elderly patients and also for palliative treatment. The literature reviewed in this article mainly demonstrates that metronomic chemotherapy is advantageous for selected patients and for certain types of malignancies, which make it a promising therapeutic approach for filling in the gaps. More clinical studies are needed to establish a solidified role for metronomic chemotherapy with other treatment models in modern cancer management.

Randomized trial of oral cyclophosphamide versus oral cyclophosphamide with celecoxib for recurrent epithelial ovarian, fallopian tube, and primary peritoneal cancer

BACKGROUND

Oral metronomic chemotherapy, which has low toxicity, has demonstrated promising anti-tumor and anti-angiogenic properties that may lead to prolonged progression-free survival and improved response rates in patients with recurrent epithelial ovarian cancer (EOC). These effects may be enhanced by the co-administration of anti-angiogenic agents.

METHODS

We conducted a randomized phase II clinical trial to evaluate the therapeutic benefit of oral metronomic cyclophosphamide (CTX) alone and with the anti-angiogenic drug celecoxib in patients with gynecological malignancies. 52 patients were randomly assigned to two treatments arms: 50 mg oral CTX daily alone (Arm A) or with 400 mg celecoxib twice daily (Arm B). The primary endpoint was response rate. Secondary endpoints included toxicity, time to treatment failure, and overall survival.

RESULTS

In Arm A (n = 26), 3 patients (12%) had stable disease >6 months and 1 (4%) had a partial response. In Arm B, 5 (19%) had stable disease >6 months and 1 patient (4%) had a partial response. There were no significant between-group differences in overall survival (9.69 months [95% CI 3.84-13.18] vs. 12.55 months [6.67-17.61]) or in median time to treatment failure (1.84 months [1.68-2.76] vs. 1.92 months [1.64-5.22]). The most common adverse events were nausea, vomiting, and abdominal pain.

CONCLUSIONS

Oral metronomic CTX has activity with no major toxicities in heavily pretreated recurrent gynecological cancers and may be considered in patients with indolent disease. We did not observe any additional benefit of celecoxib treatment, though this may be due to small sample sizes.

[Metronomic chemotherapy with oral cyclophosphamide : An individual option for the metastatic castration-resistant prostate cancer patient?]

BACKGROUND

Multiple experimental approaches are meanwhile available for progressive metastatic castration resistant prostate cancer (mCRPC) patients after failure of guideline recommended therapy (i. e., chemotherapy and/or hormonal treatment). We evaluated the outcome of metronomic chemotherapy with cyclophosphamide (CY) in combination with low-dose prednisolone.

MATERIALS AND METHODS

A total of 14 mCRPC-patients were treated with CY 50 mg/day (plus prednisolone 10 mg/day) between November 2012 and September 2017 after being resistant or unfit for chemotherapy and/or further hormonal treatment. Time to progression and overall survival (OS) were retrospectively determined by using Kaplan-Meier curves.

RESULTS

Eight of 14 (57.1%) patients had undergone radical prostatectomy and 2 (14.3%) external beam radiation. All patients had at least three therapy lines and 50% had ≥5 mCRPC therapies. The median time from first diagnosis to mCRPC was 88 months; the median age was 78 years with a median baseline serum prostate-specific antigen (PSA) level of 341 ng/ml. With a median follow-up of 16.4 months, progression-free survival (PFS) was 71, 64, and 43% after 2, 4, and 6 months, respectively. Median OS was 8.1 months. No relevant adverse events occurred.

CONCLUSION

Since CY is a well-tolerated medication with partially good clinical tumor control, it seems to be a convenient, individual treatment option in progressive mCRPC patients after failure of guideline recommended therapy.

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.

Autophagy activated by the c-Jun N-terminal kinase-mediated pathway protects human prostate cancer PC3 cells from celecoxib-induced apoptosis

The aim of the present study was to investigate the role of autophagy in celecoxib-induced apoptosis in human hormone-insensitive prostate cancer cell line PC3 cells and to explore the underlying molecular mechanism leading to autophagic activation. A cell viability assay was applied to investigate the effect of various concentrations of celecoxib (0, 40, 60, 80, 100 and 120 µmol/l) on PC3 cells for 24 and 48 h, respectively. The 50% inhibitory concentration of celecoxib for 24 h was chosen for subsequent experiments. Annexin V-fluorescein isothiocyanate/propidium iodide double staining flow cytometry, as well as caspase 3 and poly (ADP-ribose) polymerase proteins detected by western blotting, were applied to analyze cellular apoptosis induced by celecoxib. Ultrastructural cellular changes observed by transmission electron microscopy and the level of LC-3 II and P62 detected by western blotting were used to determine the activation of autophagy. It was demonstrated that celecoxib induced apoptosis and activated autophagy in PC3 cells in a dose- and time-dependent manner. Furthermore, flow cytometry and western blotting were applied to elucidate whether the role of autophagy in celecoxib-induced apoptosis is protective or destructive. Blockade of autophagy markedly increased apoptosis, suggesting that celecoxib-activated autophagy was cytoprotective. Additionally, c-jun-N-terminal kinase (JNK) was demonstrated to have a role in autophagic activation, and suppression of JNK was able to reduce autophagy and increase apoptosis. In conclusion, the results of the present study indicate that celecoxib induces apoptosis in PC3 cells; however, celecoxib also activates JNK-mediated autophagy, which exerts cytoprotective effects in prostate cancer PC3 cells. Blockade of autophagy via the JNK-mediated pathway may provide a promising strategy for prostate cancer therapy.

Anthelmintic drug albendazole arrests human gastric cancer cells at the mitotic phase and induces apoptosis

As microtubules have a vital function in the cell cycle, oncologists have developed microtubule inhibitors capable of preventing uncontrolled cell division, as in the case of cancer. The anthelmintic drug albendazole (ABZ) has been demonstrated to inhibit hepatocellular, ovarian and prostate cancer cells via microtubule targeting. However, its activity against human gastric cancer (GC) cells has remained to be determined. In the present study, ABZ was used to treat GC cells (MKN-45, SGC-7901 and MKN-28). A a CCK-8 cell proliferation assay was performed to assess the effects of ABZ on cell viability and cell cycle changes were assessed using flow cytometry. SGC-7901 cells were selected for further study, and flow cytometry was employed to determine the apoptotic rate, immunofluorescence analysis was employed to show changes of the microtubule structure as well as the subcellular localization and expression levels of cyclin B1, and western blot analysis was used to identify the dynamics of microtubule assembly. The expression levels of relevant proteins, including cyclin B1 and Cdc2, the two subunits of mitosis-promoting factor as well as apoptosis-asociated proteins were also assessed by western blot analysis. The results showed that ABZ exerted its anti-cancer activity in GC cell lines by disrupting microtubule formation and function to cause mitotic arrest, which is also associated with the accumulation of cyclin B1, and consequently induces apoptosis.

RhoGDI deficiency induces constitutive activation of Rho GTPases and COX-2 pathways in association with breast cancer progression

Rho GDP Dissociation Inhibitor (RhoGDI) is a key regulator of Rho GTPases. Here we report that loss of RhoGDI significantly accelerated xenograft tumor growth of MDA-MB-231 cells in animal models. At the molecular level, RhoGDI depletion resulted in constitutive activation of Rho GTPases, including RhoA, Cdc42, and Rac1. This was accompanied by Rho GTPase translocation from the cytosol to membrane compartments. Notably, COX-2 protein levels, mRNA expression, and biological activity were markedly increased in RhoGDI-deficient cells. The upregulated expression of COX-2 was directly associated with increased Rho GTPase activity. Further, we assessed the expression level of RhoGDI protein in breast tumor specimens (n = 165) by immunohistochemistry. We found that RhoGDI expression is higher in the early stages of breast cancer followed by a significant decrease in malignant tumors and metastatic lesions (p < 0.01). These data suggest that downregulation of RhoGDI could be a critical mechanism of breast tumor development, which may involve the hyperactivation of Rho GTPases and upregulation of COX-2 activity. Additional studies are warranted to evaluate the therapeutic potential of inhibiting Rho GTPases and COX-2 for treating breast cancers.

Celecoxib and octreotide synergistically ameliorate portal hypertension via inhibition of angiogenesis in cirrhotic rats

Abnormal angiogenesis is critical for portal hypertension in cirrhosis. Except for etiological treatment, no efficient medication or regime has been explored to treat the early stage of cirrhosis when angiogenesis is initiated or overwhelming. In this study, we explored an anti-angiogenesis effort through non-cytotoxic drugs octreotide and celecoxib to treat early stage of cirrhotic portal hypertension in an animal model. Peritoneal injection of thioacetamide (TAA) was employed to induce liver cirrhosis in rats. A combination treatment of celecoxib and octreotide was found to relieve liver fibrosis, portal venous pressure, micro-hepatic arterioportal fistulas, intrahepatic and splanchnic angiogenesis. Celecoxib and octreotide exerted their anti-angiogenesis effect via an axis of cyclooxygenase-2/prostaglandin E2/EP-2/somatostatin receptor-2, which consequently down-regulated phosphorylation of extracellular signal-regulated kinase (p-ERK)–hypoxia-inducible factor-1α (HIF-1α)–vascular endothelial growth factor (VEGF) integrated signaling pathways. In conclusions, combination of celecoxib and octreotide synergistically ameliorated liver fibrosis and portal hypertension of the cirrhotic rats induced by TAA via the inhibition of intrahepatic and extrahepatic angiogenesis. The potential mechanisms behind the regimen may due to the inactivation of p-ERK–HIF-1α–VEGF signaling pathway.

Adjuvant therapy for highly malignant canine mammary tumours: Cox-2 inhibitor versus chemotherapy: a case-control prospective study

Cyclooxygenase-2 (Cox-2) enzyme participates in different steps of the carcinogenetic process and in canine mammary tumours (CMTs), a high expression of Cox-2 is associated with malignancy and tumour angiogenesis. The objectives of the study were to evaluate the disease-free survival (DFS) and overall survival (OS) of a Cox-2 inhibitor as adjuvant therapy in dogs with highly malignant (HM)-CMTs and compare it with that of dogs treated with chemotherapy and with control dogs. Twenty-eight dogs were prospectively included. After surgery, dogs were alternatively allocated into two treatment groups (chemotherapy with mitoxantrone n=8; Cox-2 inhibitor, firocoxib n=7). Control group (n=13) included dogs whose owners rejected adjuvant therapy. All dogs were followed up for two years or until death. The DFS was significantly higher in dogs that received adjuvant treatment (mitoxantrone or firocoxib) (P=0.030) than in control dogs. Dogs on firocoxib treatment had significantly higher DFS (P=0.015) and OS (P=0.048) than control dogs. The DFS and OS of dogs on mitoxantrone treatment were not statistically different from controls. In conclusion, this study supports the use of firocoxib for the treatment of HM-CMTs. Further studies are needed to compare the efficacy of chemotherapy drugs versus Cox-2 inhibitors as adjuvant treatment in these cases.

Metronomic Chemotherapy for Metastatic Breast Cancer - a Systematic Review of the Literature

Conventional chemotherapy is generally administered in high doses followed by a treatment-free period to give the body needful time to recover. This "maximum tolerated dose" approach results in high response rates. However, long periods between therapy cycles can lead to development of resistance mechanisms and consequently disease progression. One of the most interesting alternative strategies is metronomic chemotherapy. This concept relies on the continuous administration of chemotherapy at low doses and aims at targeting endothelial cells in the tumor bed as well. Recently, metronomic chemotherapy has been incorporated into the recommendations issued by the German AGO expert panel (www.ago-online.de). A systematic review of PubMed/Medline, ClinicalTrials.gov, the European Clinical Trials Database (EudraCT) and the Cochrane Database was conducted. In the present review, we discuss the current evidence on metronomic chemotherapy in metastatic breast cancer.

Quality of life in patients with metastatic breast cancer treated with metronomic chemotherapy

AIM

The objective of the study was to detect changes in quality of life (QoL) in metastatic breast cancer patients treated with metronomic chemotherapy with daily low doses of cyclophosphamide and celecoxib.

MATERIAL & METHODS

Patients included in a Phase II trial, treated with metronomic cyclophosphamide and celecoxib were included in the QoL study. Assessment of QoL was carried out every 2 months by the Functional Assessment of Cancer Therapy Breast (FACT-B) questionnaire, Brief Pain Inventory and Eastern Cooperative Oncologic Group scale. Data were analyzed at three time points: baseline (BL); middle of treatment (MT); and end of treatment (ET).

RESULTS

A total of 20 patients were included. All patients were heavily pretreated. Treatment showed a good and safe therapeutic profile. With FACT-B questionnaire, no significant differences were observed during the response period (BL-MT). However, a significant increase was observed in the Emotional well-being and Additional concerns axes, when the last time point was included in the analysis (BL-MT-ET). A significant decrease in the proportion of patients with pain was found when comparing BL with ET (p = 0.046). The assessment with Eastern Cooperative Oncologic Group scale showed that 26.7% (4/15) of the patients improved their functional status and 40% (6/15) showed no changes, while 33.3% (5/10) worsened it.

CONCLUSION

Patients treated metronomically for several months did not worsen their QoL. A high proportion of patients showed improvement or no changes and there were less patients with pain at the end of the treatment.

Repurposing Drugs in Oncology (ReDO)-diclofenac as an anti-cancer agent

Diclofenac (DCF) is a well-known and widely used non-steroidal anti-inflammatory drug (NSAID), with a range of actions which are of interest in an oncological context. While there has long been an interest in the use of NSAIDs in chemoprevention, there is now emerging evidence that such drugs may have activity in a treatment setting. DCF, which is a potent inhibitor of COX-2 and prostaglandin E2 synthesis, displays a range of effects on the immune system, the angiogenic cascade, chemo- and radio-sensitivity and tumour metabolism. Both pre-clinical and clinical evidence of these effects, in multiple cancer types, is assessed and summarised and relevant mechanisms of action outlined. Based on this evidence the case is made for further clinical investigation of the anticancer effects of DCF, particularly in combination with other agents - with a range of possible multi-drug and multi-modality combinations outlined in the supplementary materials accompanying the main paper.

Metastatic breast cancer patients treated with low-dose metronomic chemotherapy with cyclophosphamide and celecoxib: clinical outcomes and biomarkers of response

BACKGROUND

Preclinical results showing therapeutic effect and low toxicity of metronomic chemotherapy with cyclophosphamide (Cy) + celecoxib (Cel) for mammary tumors encouraged its translation to the clinic for treating advanced breast cancer patients (ABCP).

PATIENTS AND METHODS

A single-arm, mono-institutional, non-randomized, phase II, two-step clinical trial (approved by Bioethics Committee and Argentine Regulatory Authority) was designed. Patients received Cy (50 mg po.d) + Cel (200 mg p.o.bid). Patient eligibility criteria included: ABCP who progressed to anthracyclines, taxanes and capecitabine, ≤4 chemotherapy schemes, with good performance status. Several pro- and anti-angiogenic molecules and cells were determined as biomarkers. Informed consent was signed by all patients. Primary endpoint was clinical benefit (CB).

RESULTS

Twenty patients were enrolled. Main clinical outcomes were prolonged disease stabilization and partial remission in 10/20 and 1/20 patients, respectively. CB was 55 %, and time to progression (TTP) was 21.1 weeks. Median TTP in patients who achieved CB was 35.6 weeks, and mean overall survival was 44.20 weeks. There were no grade 3/4 toxicities associated with treatment. Circulating endothelial cells (CECs) increased at the time of progression in patients who showed CB (P = 0.014). Baseline CECs and circulating endothelial progenitor cells showed marginal associations with TTP. Serum VEGF decreased (P = 0.050), sVEGFR-2 increased (P = 0.005) and VEGF/sVEGFR-2 ratio decreased during treatment (P = 0.041); baseline VEGF and VEGF/sVEGFR-2 were associated with TTP (P = 0.035 and P = 0.030, respectively), while sVEGFR-2 did not.

CONCLUSIONS

Treatment was effective, showing low toxicity profile and excellent tolerability. The combination had anti-angiogenic effect. Increased levels of CEC could be useful for detecting progression. Baseline VEGF and VEGF/sVEGFR-2 values could be useful as early predictors of response.

TRIAL REGISTRATION

ANMAT#4596/09.

CUSP9* treatment protocol for recurrent glioblastoma: aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, ritonavir, sertraline augmenting continuous low dose temozolomide

CUSP9 treatment protocol for recurrent glioblastoma was published one year ago. We now present a slight modification, designated CUSP9*. CUSP9* drugs--aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, sertraline, ritonavir, are all widely approved by regulatory authorities, marketed for non-cancer indications. Each drug inhibits one or more important growth-enhancing pathways used by glioblastoma. By blocking survival paths, the aim is to render temozolomide, the current standard cytotoxic drug used in primary glioblastoma treatment, more effective. Although esthetically unpleasing to use so many drugs at once, the closely similar drugs of the original CUSP9 used together have been well-tolerated when given on a compassionate-use basis in the cases that have come to our attention so far. We expect similarly good tolerability for CUSP9*. The combined action of this suite of drugs blocks signaling at, or the activity of, AKT phosphorylation, aldehyde dehydrogenase, angiotensin converting enzyme, carbonic anhydrase -2,- 9, -12, cyclooxygenase-1 and -2, cathepsin B, Hedgehog, interleukin-6, 5-lipoxygenase, matrix metalloproteinase -2 and -9, mammalian target of rapamycin, neurokinin-1, p-gp efflux pump, thioredoxin reductase, tissue factor, 20 kDa translationally controlled tumor protein, and vascular endothelial growth factor. We believe that given the current prognosis after a glioblastoma has recurred, a trial of CUSP9* is warranted.

Metronomic chemotherapy in the neoadjuvant setting: results of two parallel feasibility trials (TraQme and TAME) in patients with HER2+ and HER2- locally advanced breast cancer

Neoadjuvant chemotherapy has practical and theoretical advantages over adjuvant chemotherapy strategy in breast cancer (BC) management. Moreover, metronomic delivery has a more favorable toxicity profile. The present study examined the feasibility of neoadjuvant metronomic chemotherapy in two cohorts [HER2+ (TraQme) and HER2− (TAME)] of locally advanced BC. Twenty patients were prospectively enrolled (TraQme, n=9; TAME, n=11). Both cohorts received weekly paclitaxel at 100 mg/m² during 8 weeks followed by weekly doxorubicin at 24 mg/m² for 9 weeks in combination with oral cyclophosphamide at 100 mg/day (fixed dose). The HER2+ cohort received weekly trastuzumab. The study was interrupted because of safety issues. Thirty-six percent of patients in the TAME cohort and all patients from the TraQme cohort had stage III BC. Of note, 33% from the TraQme cohort and 66% from the TAME cohort displayed hormone receptor positivity in tumor tissue. The pathological complete response rates were 55% and 18% among patients enrolled in the TraQme and TAME cohorts, respectively. Patients in the TraQme cohort had more advanced BC stages at diagnosis, higher-grade pathological classification, and more tumors lacking hormone receptor expression, compared to the TAME cohort. The toxicity profile was also different. Two patients in the TraQme cohort developed pneumonitis, and in the TAME cohort we observed more hematological toxicity and hand-foot syndrome. The neoadjuvant metronomic chemotherapy regimen evaluated in this trial was highly effective in achieving a tumor response, especially in the HER2+ cohort. Pneumonitis was a serious, unexpected adverse event observed in this group. Further larger and randomized trials are warranted to evaluate the association between metronomic chemotherapy and trastuzumab treatment.

The SK-N-AS human neuroblastoma cell line develops osteolytic bone metastases with increased angiogenesis and COX-2 expression

Neuroblastoma (NB), which arises from embryonic neural crest cells, is the most common extra-cranial solid tumor of childhood. Approximately half of NB patients manifest bone metastasis accompanied with bone pain, fractures and bone marrow failure, leading to disturbed quality of life and poor survival. To study the mechanism of bone metastasis of NB, we established an animal model in which intracardiac inoculation of the SK-N-AS human NB cells in nude mice developed osteolytic bone metastases with increased osteoclastogenesis. SK-N-AS cells induced the expression of receptor activator of NF-κB ligand and osteoclastogenesis in mouse bone marrow cells in the co-culture. SK-N-AS cells expressed COX-2 mRNA and produced substantial amounts of prostaglandin E₂ (PGE₂). In contrast, the SK-N-DZ and SK-N-FI human NB cells failed to develop bone metastases, induce osteoclastogenesis, express COX-2 mRNA and produce PGE₂. Immunohistochemical examination of SK-N-AS bone metastasis and subcutaneous tumor showed strong expression of COX-2. The selective COX-2 inhibitor NS-398 inhibited PGE₂ production and suppressed bone metastases with reduced osteoclastogenesis. NS-398 also inhibited subcutaneous SK-N-AS tumor development with decreased angiogenesis and vascular endothelial growth factor-A expression. Of interest, metastasis to the adrenal gland, a preferential site for NB development, was also diminished by NS-398. Our results suggest that COX2/PGE₂ axis plays a critical role in the pathophysiology of osteolytic bone metastases and tumor development of the SK-NS-AS human NB. Inhibition of angiogenesis by suppressing COX-2/PGE₂ may be an effective therapeutic approach for children with NB.

Lessons from the Fourth Metronomic and Anti-angiogenic Therapy Meeting, 24-25 June 2014, Milan

The Fourth Metronomic and Anti-angiogenic Therapy Meeting was held in Milan 24–25 June 2014. The meeting was a true translational meeting where researchers and clinicians shared their results, experiences, and insights in order to continue gathering useful evidence on metronomic approaches. Several speakers emphasised that exact mechanisms of action, best timing, and optimal dosage are still not well understood and that the field would learn a lot from ancillary studies performed during the clinical trials of metronomic chemotherapies. From the pre-clinical side, new research findings indicate additional possible mechanisms of actions of metronomic schedule on the immune and blood vessel compartments of the tumour micro-environment. New clinical results of metronomic chemotherapy were presented in particular in paediatric cancers [especially neuroblastoma and central nervous system (CNS) tumours], in angiosarcoma (together with beta-blockers), in hepatocellular carcinoma, in prostate cancer, and in breast cancer. The use of repurposed drugs such as metformin, celecoxib, or valproic acid in the metronomic regimen was reported and highlighted the potential of other candidate drugs to be repurposed. The clinical experiences from low- and middle-income countries with affordable regimens gave very encouraging results which will allow more patients to be effectively treated in economies where new drugs are not accessible. Looking at the impact of metronomic approaches that have been shown to be effective, it was admitted that those approaches were rarely used in clinical practice, in part because of the absence of commercial interest for companies. However, performing well-designed clinical trials of metronomic and repurposing approaches demonstrating substantial improvement, especially in populations with the greatest unmet needs, may be an easier solution than addressing the financial issue. Metronomics should always be seen as a chance to come up with new innovative affordable approaches and not as a cheap rescue strategy.

A low carbohydrate, high protein diet combined with celecoxib markedly reduces metastasis

We recently demonstrated that both murine and human carcinomas grow significantly slower in mice on low carbohydrate (CHO), high protein diets than on isocaloric Western diets and that a further reduction in tumor growth rates occur when the low CHO diets are combined with the cyclooxygenase-2 inhibitor, celecoxib. Following upon these studies, we asked herein what effect low CHO, high protein diets, with or without celecoxib, might have on tumor metastasis. In the highly metastatic 4T1 mouse mammary tumor model, a 15% CHO, high protein diet supplemented with celecoxib (1 g/kg chow) markedly reduced lung metastases. Moreover, in longer-term studies using male Transgenic Adenocarcinoma of the Mouse Prostate mice, which are predisposed to metastatic prostate cancer, the 15% CHO diet, with and without celecoxib (0.3 g/kg chow), gave the lowest incidence of metastases, but a more moderate 25% CHO diet containing celecoxib led to the best survival. Metabolic studies with 4T1 tumors suggested that the low CHO, high protein diets may be forcing tumors to become dependent on amino acid catabolism for survival/growth. Taken together, our results suggest that a combination of a low CHO, high protein diet with celecoxib substantially reduces metastasis.

Metronomic therapy and breast cancer: a systematic review

Metronomic therapy (MT) refers to repetitive, low doses of chemotherapy drugs. MT exerts an effect not only on tumour cells, but also on their microenvironment. In particular, the low-dose schedule compromises the repairing process of endothelial cells, leading to an anti-angiogenic effect. In addition to the anti-angiogenic effect, MT could have an immunological action through the restoration of the anticancer effect of the immune system and induction of tumour dormancy. Consequently the association of targeted therapy with anti-angiogenic properties or specific immunologic drugs could enhance the efficacy of MT. During the past 15 years, several studies have been published evaluating the metronomic strategy in breast cancer. We conducted a systematic review of the results of phase I, II and III studies testing MT in breast cancer patients. The analyses included the efficacy and toxicity data of MT, and the future development of this strategy in breast cancer are also discussed. The systematic review presented here suggests that MT is a treatment option for breast cancer patients, has a low toxicity profile, efficacy in most patients and has potentially significant cost-effective advantages for public health.

Metronomics: towards personalized chemotherapy?

Since its inception in 2000, metronomic chemotherapy has undergone major advances as an antiangiogenic therapy. The discovery of the pro-immune properties of chemotherapy and its direct effects on cancer cells has established the intrinsic multitargeted nature of this therapeutic approach. The past 10 years have seen a marked rise in clinical trials of metronomic chemotherapy, and it is increasingly combined in the clinic with conventional treatments, such as maximum-tolerated dose chemotherapy and radiotherapy, as well as with novel therapeutic strategies, such as drug repositioning, targeted agents and immunotherapy. We review the latest advances in understanding the complex mechanisms of action of metronomic chemotherapy, and the recently identified factors associated with disease resistance. We comprehensively discuss the latest clinical data obtained from studies performed in both adult and paediatric populations, and highlight ongoing clinical trials. In this Review, we foresee the future developments of metronomic chemotherapy and specifically its potential role in the era of personalized medicine.

Comparative effectiveness of two metronomic chemotherapy schedules-our experience in the preclinical field

Metronomic chemotherapy refers to the chronic, equally spaced, delivery of low doses of chemotherapeutic drugs, without extended interruptions. Previously, we developed two combined metronomic schemes for the treatment of murine mammary tumors. The aim of this study was to compare their effects on tumor and metastasis growth, survival, and toxicity. Metronomic chemotherapy with Cyclophosphamide + Celecoxib (Cy + Cel) showed higher antimetastatic power than Cyclophosphamide + Doxorubicin (Cy + Dox), while being similar in other aspects. That difference, plus the advantage that represents its oral administration, suggests that the Cy + Cel combination is more suitable than Cy + Dox for metronomic chemotherapy of mammary tumors and could be proposed to the translation to the clinic.

Pathway analysis for drug repositioning based on public database mining

Sixteen FDA-approved drugs were investigated to elucidate their mechanisms of action (MOAs) and clinical functions by pathway analysis based on retrieved drug targets interacting with or affected by the investigated drugs. Protein and gene targets and associated pathways were obtained by data-mining of public databases including the MMDB, PubChem BioAssay, GEO DataSets, and the BioSystems databases. Entrez E-Utilities were applied, and in-house Ruby scripts were developed for data retrieval and pathway analysis to identify and evaluate relevant pathways common to the retrieved drug targets. Pathways pertinent to clinical uses or MOAs were obtained for most drugs. Interestingly, some drugs identified pathways responsible for other diseases than their current therapeutic uses, and these pathways were verified retrospectively by in vitro tests, in vivo tests, or clinical trials. The pathway enrichment analysis based on drug target information from public databases could provide a novel approach for elucidating drug MOAs and repositioning, therefore benefiting the discovery of new therapeutic treatments for diseases.

Isoliquiritigen enhances the antitumour activity and decreases the genotoxic effect of cyclophosphamide

The aim of this study was to evaluate the antitumour activities and genotoxic effects of isoliquiritigenin (ISL) combined with cyclophosphamide (CP) in vitro and in vivo. U14 cells were treated with either of ISL (5-25 μg/mL) or CP (0.25-1.25 mg/mL) alone or with combination of ISL (5-25 μg/mL) and CP (1.0 mg/mL) for 48 h. The proliferation inhibitory effect in vitro was evaluated by MTT and colony formation assays. KM mice bearing U14 mouse cervical cancer cells were used to estimate the antitumour activity in vivo. The genotoxic activity in bone marrow polychromatic erythrocytes was assayed by frequency of micronuclei. The DNA damage in peripheral white blood cells was assayed by single cell gel electrophoresis. The results showed that ISL enhanced antitumour activity of CP in vitro and in vivo, and decreased the micronucleus formation in polychromatic erythrocytes and DNA strand breaks in white blood cells in a dose-dependent way.

Therapeutic efficacy of metronomic chemotherapy with cyclophosphamide and doxorubicin on murine mammary adenocarcinomas

BACKGROUND

Metronomic chemotherapy (MCT) refers to the chronic and equally spaced administration of low doses of different chemotherapy drugs, without extended rest periods. Herein, we investigated the therapeutic efficacy of metronomic cyclophosphamide (Cy) combined with doxorubicin (Dox) in two mouse mammary adenocarcinoma models.

MATERIALS AND METHODS

Mice were s.c. challenged with M-234p or M-406 mammary tumors, and when the tumors reached ∼150 mm(3), they were treated with: (I) no treatment (controls); (II) Cy in the drinking water (30 mg/kg body weight/day); (III) Dox (0.5 mg/kg body weight i.p. three times/week); (IV) treated as (II) + (III). Mice challenged i.v. with M-234p or M-406 tumor cells received, on day 3, the same treatments.

RESULTS

We found that MCT with Cy plus Dox inhibited tumor growth, decreased lung metastases, and increased the median survival time, while having low toxic effect. Combined MCT was more effective than each monotherapy causing decrease in VEGF serum concentration and tumor proliferation rate plus increase in tumor apoptosis.

CONCLUSION(S)

The therapeutic benefits of combined MCT with Cy and Dox on mammary adenocarcinomas together with its low toxic effect profile suggest the possibility of future translation into the clinic.