Low-dose Metronomic Chemotherapy Research Articles

Metronomic chemotherapy in hematology: Lessons from preclinical and clinical studies to build a solid rationale for future schedules

Metronomic chemotherapy (mCHEMO), based on frequent, regular administration of low, but pharmacologically active drug doses, optimizes antitumor efficacy by targeting multiple targets and reducing toxicity of antineoplastic drugs. This minireview will summarize preclinical and clinical studies on cytotoxic drugs given at weekly, daily, or at continuous metronomic schedules alone or in combination with novel targeted agents for hematological malignancies, including lymphoma, multiple myeloma, and leukemia. Most of the preclinical in vitro and in vivo studies have reported a significant benefit of both mCHEMO monotherapy and combinatorial regimens compared with chemotherapy at the maximum tolerated dose. However, the combination of mCHEMO with targeted drugs is still little explored in the hematologic clinical setting. Data obtained from preclinical studies on low dose metronomic chemotherapy in hematological malignancies clearly suggested the possibility to clinically investigate more tolerable and effective strategies for the treatment of patients with advanced hematological malignancies, or at least for those frail and elderly patients, who are not eligible or resistant to standard treatments.

Peroxisome proliferator-activated receptorα/γ agonist pioglitazone for rescuing relapsed or refractory neoplasias by unlocking phenotypic plasticity.

A series of seven clinical trials on relapsed or refractory (r/r) metastatic neoplasias followed the question: Are networks of ligand-receptor cross-talks that support tumor-specific cancer hallmarks, druggable with tumor tissue editing approaches therapeutically exploiting tumor plasticity? Differential recombinations of pioglitazone, a dual peroxisome-proliferator activated receptorα/γ (PPARα/γ) agonist, with transcriptional modulators, i.e., all-trans retinoic acid, interferon-α, or dexamethasone plus metronomic low-dose chemotherapy (MCT) or epigenetic modeling with azacitidine plus/minus cyclooxygenase-2 inhibition initiated tumor-specific reprogramming of cancer hallmarks, as exemplified by inflammation control in r/r melanoma, renal clear cell carcinoma (RCCC), Hodgkin's lymphoma (HL) and multisystem Langerhans cell histiocytosis (mLCH) or differentiation induction in non-promyelocytic acute myeloid leukemia (non-PML AML). Pioglitazone, integrated in differentially designed editing schedules, facilitated induction of tumor cell death as indicated by complete remission (CR) in r/r non-PML AML, continuous CR in r/r RCCC, mLCH, and in HL by addition of everolimus, or long-term disease control in melanoma by efficaciously controlling metastasis, post-therapy cancer repopulation and acquired cell-resistance and genetic/molecular-genetic tumor cell heterogeneity (M-CRAC). PPARα/γ agonists provided tumor-type agnostic biomodulatory efficacy across different histologic neoplasias. Tissue editing techniques disclose that wide-ranging functions of PPARα/γ agonists may be on-topic focused for differentially unlocking tumor phenotypes. Low-dose MCT facilitates targeted reprogramming of cancer hallmarks with transcriptional modulators, induction of tumor cell death, M-CRAC control and editing of non-oncogene addiction. Thus, pioglitazone, integrated in tumor tissue editing protocols, is an important biomodulatory drug for addressing urgent therapeutic problems, such as M-CRAC in relapsed or refractory tumor disease.

Addressing Genetic Tumor Heterogeneity, Post-Therapy Metastatic Spread, Cancer Repopulation, and Development of Acquired Tumor Cell Resistance.

The concept of post-therapy metastatic spread, cancer repopulation and acquired tumor cell resistance (M-CRAC) rationalizes tumor progression because of tumor cell heterogeneity arising from post-therapy genetic damage and subsequent tissue repair mechanisms. Therapeutic strategies designed to specifically address M-CRAC involve tissue editing approaches, such as low-dose metronomic chemotherapy and the use of transcriptional modulators with or without targeted therapies. Notably, tumor tissue editing holds the potential to treat patients, who are refractory to or relapsing (r/r) after conventional chemotherapy, which is usually based on administering a maximum tolerable dose of a cytostatic drugs. Clinical trials enrolling patients with r/r malignancies, e.g., non-small cell lung cancer, Hodgkin's lymphoma, Langerhans cell histiocytosis and acute myelocytic leukemia, indicate that tissue editing approaches could yield tangible clinical benefit. In contrast to conventional chemotherapy or state-of-the-art precision medicine, tissue editing employs a multi-pronged approach targeting important drivers of M-CRAC across various tumor entities, thereby, simultaneously engaging tumor cell differentiation, immunomodulation, and inflammation control. In this review, we highlight the M-CRAC concept as a major factor in resistance to conventional cancer therapies and discusses tissue editing as a potential treatment.

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

Conventional chemotherapy is based on the maximum tolerated dose (MTD) and requires treatment-free intervals to restore normal host cells. MTD chemotherapy may induce angiogenesis or immunosuppressive cell infiltration during treatment-free intervals. Low-dose metronomic (LDM) chemotherapy is defined as frequent administration at lower doses and causes less inflammatory change, whereas MTD chemotherapy induces an inflammatory change. Although several LDM regimens have been applied, LDM cisplatin (CDDP) has been rarely reported. This study addressed the efficacy of LDM CDDP on tumour endothelial cell phenotypic alteration compared to MTD CDDP. Tumour growth and metastasis were assessed in bladder cancer-bearing mice treated with LDM or MTD gemcitabine (GEM) and CDDP. To elucidate the therapeutic effects of LDM CDDP, the change of tumour vasculature, tumour-infiltrating immune cells and inflammatory changes were evaluated by histological analysis and mRNA expression in tumour tissues. Tumour growth and bone metastasis were more suppressed by LDM CDDP + MTD GEM treatment than MTD CDDP + MTD GEM. Myeloid-derived suppressor cell accumulation was reduced by LDM CDDP, whereas inflammatory change was induced in the tumour microenvironment by MTD CDDP. LDM CDDP does not cause inflammatory change unlike MTD CDDP, suggesting that it is a promising strategy in chemotherapy.

Low-dose Cisplatin Induces Tumor Growth via Mobilization of Proangiogenic Bone Marrow-derived Cells in Mouse Models.

It is generally accepted that low-dose metronomic (LDM) chemotherapy mostly exerts its antitumor effects by inhibiting tumor angiogenesis. However, there is some evidence that LDM chemotherapy subsequently promotes tumor angiogenesis under certain regimens in animal models. The mechanisms responsible for these contradictory results are unclear. Cisplatin (CDDP) was intraperitoneally administered to tumor-bearing mice at doses of 0.05-3 mg/kg every other day. The effects of LDM chemotherapy with CDDP on tumor growth and angiogenesis were observed. To determine the involved mechanisms, we analyzed the expression of vascular basement membrane proteins, transcription of angiogenesis-related genes in tumor tissues, and mobilization of proangiogenic bone marrow-derived cells (BMDCs) in circulating blood. The mean tumor weight with the 3 mg/kg q.o.d. regimen CDDP was significantly lower (by 57.3%) in the CDDP than in the control group. However, the tumor weight was 52.1% higher for the 0.19 mg/kg q.o.d. regimen in the CDDP group, which could be antagonized using 30 mg/kg all-trans retinoic acid. For the 0.19 mg/kg q.o.d., more tumor vascular structures were observed in the CDDP than in the control group (47.9±5.0 vs. 22.3±0.8, p<0.001). The mobilization of VEGFR2+ BMDCs and the mRNA expression of the proangiogenic genes MMP9, VEGFR1, VEGFR2 and VE-cadherin were increased in the 0.19 mg/kg regimen. These results indicate that metronomic CDDP promoted tumor angiogenesis and tumor growth via increased mobilization of proangiogenic BMDCs at certain low doses. This implies a potential therapeutic risk from an inappropriate LDM chemotherapy dosage and suggests that optimizing the LDM chemotherapy regimen is urgently needed.

Low-dose metronomic chemotherapy triggers oxidized mtDNA sensing inside tumor cells to potentiate CD8+T anti-tumor immunity

Low-dose metronomic (LDM) chemotherapy, the frequent and continuous use of low doses of conventional chemotherapeutics, is emerging as a promising form of chemotherapy utilization. LDM chemotherapy exerts immunomodulatory effects. However, the underlying mechanism is not fully understood. Here we found that suppressing tumor growth by LDM chemotherapy was dependent on the activation of CD8+T cells. LDM chemotherapy potentiated the cytotoxic function of CD8+T cells by stimulating cancer-cell autonomous type I interferon (IFN) induction. Mechanistically, LDM chemotherapy evoked mitochondrial dysfunction and increased reactive oxygen species (ROS) production. ROS triggered the oxidation of cytosolic mtDNA, which was sensed by cGAS-STING, consequently inducing type I IFN production in the cancer cells. Moreover, the cGAS-STING-IFN axis increased PD-L1 expression and predicted favorable clinical responses to chemoimmunotherapy. Antioxidant N-acetylcysteine inhibited oxidized mtDNA-induced type I IFN production and attenuated the efficacy of combination therapy with LDM chemotherapy and PD-L1 blockade. This study elucidates the critical role of intratumoral oxidized mtDNA sensing in LDM chemotherapy-mediated activation of CD8+T cell immune response. These findings may provide new insights for designing combinatorial immunotherapy for cancer patients.

LGG-10. TREATMENT-RELATED MYELODYSPLASTIC SYNDROME FOLLOWING CHEMOTHERAPY FOR PEDIATRIC LOW-GRADE GLIOMA

Abstract Treatment-related myeloid neoplasms are rare though well-defined secondary malignancies associated with prior cytotoxic treatment, (particularly alkylating agents and topoisomerase inhibitors). They are rarely associated with primary central nervous system tumours and have historically carried a very poor prognosis. Pediatric low-grade gliomas (pLGG) are the most common CNS tumours of childhood, and up to 50% of patients will require adjuvant therapy. This has traditionally consisted of low-dose metronomic chemotherapy, although the advent of genomic profiling and identification of molecular drivers of pLGG means novel targeted therapies are changing this paradigm. There has only been a single reported case of treatment-related myeloid leukaemia secondary to pLGG treatment. We present a novel case of a 17-year-old girl with treatment-related myelodysplastic syndrome following chemotherapeutic treatment for pLGG. The patient was initially diagnosed at age 4 with a metastatic pilomyxoid astrocytoma (primary suprasellar lesion with spinal metastases) and received first-line treatment with a vincristine and carboplatin regimen. She had disease progression at age 7 and received second-line treatment with thioguanine, procarbazine, lomustine and vincristine. Following further progression at age 16, a biopsy of the suprasellar mass showed a pilocytic astrocytoma with a KIAA1549-BRAF fusion. Prior to commencing a targeted treatment as third-line therapy, she was noted to have a macrocytic anaemia, which subsequently evolved to a bicytopenia. Bone marrow analysis showed a hypocellular marrow with an abnormal myeloid clone with a chromosomal 1q gain, consistent with a diagnosis of treatment-related myelodysplastic syndrome. Germline analysis was negative for bone marrow failure predisposition gene abnormalities. She is currently undergoing workup for bone marrow transplant. Given the poor prognosis of treatment-related myeloid neoplasms, this case represents an important note of caution when choosing appropriate therapy for pLGG, especially given the evolving role for targeted treatments in this disease with otherwise very favourable long-term survival.

A multicenter, phase II trial of maintenance sirolimus in combination with metronomic chemotherapy in children and adolescents with high-risk solid tumors.

TPS10072 Background: Risk of relapse for children with high-risk solid tumors (ST) remains unacceptably high despite aggressive multimodal therapy. Maintenance therapy is an emerging option to improve outcomes. Sirolimus, an inhibitor of mammalian target of rapamycin, is a potent immunosuppressant with antiproliferative and antiangiogenic effects. Low-dose metronomic chemotherapy along with the cyclooxygenase-2 inhibitor celecoxib also decreases neovascularization in in vitro and in vivo systems. The maximum tolerated dose (MTD) of sirolimus in combination with celecoxib and etoposide alternating with cyclophosphamide was determined in a phase I study in pediatric patients with relapsed/refractory ST. The regimen was well-tolerated and showed best response of stable disease in 8/18 subjects and partial response in 1/18. The efficacy of this regimen in relapsed/refractory ST is being tested in a Phase II study (NCT02574728). We hypothesize that patients with high-risk ST administered a 12-month course of this maintenance regimen will have improved 2-year progression-free survival (PFS) when compared to matched historical patients who were observed following completion of upfront therapy. Methods: This is a phase II study of sirolimus in combination with celecoxib and alternating low-dose etoposide and cyclophosphamide delivered as maintenance therapy. Sirolimus will be given at the MTD of 2mg/m2/day with celecoxib 100mg twice daily and oral etoposide 50mg/m2/day (max 100mg) alternating every 21 days with oral cyclophosphamide 2.5mg/kg/day (max 100mg). This study includes: 1) a prospective cohort of patients with high-risk ST in first complete remission (CR), 2) a prospective cohort of patients with recurrent ST in second CR, and 3) a historical cohort matched 2:1 with cohort 1 on diagnosis, age, metastatic sites, and date of diagnosis treated with observation following upfront therapy. The study will enroll up to 38 patients in cohort 1. Eligible subjects are children (1-30 years) with a diagnosis of high-risk extracranial ST (metastatic sarcoma, desmoplastic small round cell tumor, malignant rhabdoid tumor) in first CR or any ST in second CR. Patients enrolled in upfront clinical trials are excluded. Primary endpoint is 2-year PFS of cohort 1 compared to the historical cohort. Secondary endpoints are median PFS of cohort 1, 2-year PFS and overall survival of cohorts 1 and 2, incidence of severe toxicities, and feasibility of completing the 12-month course following standard upfront therapy. Exploratory objectives include evaluation of circulating tumor DNA (ctDNA) in this population of patients in CR or with minimal disease burden and correlation of clinically obtained tumor molecular profiling with outcomes. As of January 2023, 12 subjects are enrolled, 9 in cohort 1 and 3 in cohort 2. Clinical trial information: NCT04469530 .

Targeting CXCL16 and STAT1 augments immune checkpoint blockade therapy in triple-negative breast cancer

Chemotherapy prior to immune checkpoint blockade (ICB) treatment appears to improve ICB efficacy but resistance to ICB remains a clinical challenge and is attributed to highly plastic myeloid cells associating with the tumor immune microenvironment (TIME). Here we show by CITE-seq single-cell transcriptomic and trajectory analyses that neoadjuvant low-dose metronomic chemotherapy (MCT) leads to a characteristic co-evolution of divergent myeloid cell subsets in female triple-negative breast cancer (TNBC). Specifically, we identify that the proportion of CXCL16 + myeloid cells increase and a high STAT1 regulon activity distinguishes Programmed Death Ligand 1 (PD-L1) expressing immature myeloid cells. Chemical inhibition of STAT1 signaling in MCT-primed breast cancer sensitizes TNBC to ICB treatment, which underscores the STAT1’s role in modulating TIME. In summary, we leverage single-cell analyses to dissect the cellular dynamics in the tumor microenvironment (TME) following neoadjuvant chemotherapy and provide a pre-clinical rationale for modulating STAT1 in combination with anti-PD-1 for TNBC patients.

Metronomic doses and drug schematic combination response tested within chambered coverslips for the treatment of breast cancer cells (JIMT-1).

Low-dose metronomic (LDM) chemotherapy is an alternative to conventional chemotherapy and is the most frequently used approach in low dose chemotherapy regimens. The selection of patients, drug dosages, and dosing intervals in LDM is empirical. In this study, we systematically examined the schedule-dependent interaction of drugs on a breast cancer cell line (BCC) cultured in chambered coverslips. The LDM studies were combined with cell staining in order to better characterize different cell states and cell death modes, including caspase-dependent apoptosis, caspase-independent cell death and autophagy-dependent cell death. Microscope images were examined using the Fiji Trainable Weka Segmentation plugin to analyse cell area in 7500 images showing different modes of cell death. Paclitaxel combined with LDM chemotherapy demonstrated a reduction in the area covered by live cells. In contrast, there was an induction of high levels of cell death due to caspase-dependent apoptosis.

PB2078: A RETROSPECTIVE ANALYSIS OF THE EFFICACY OF LOW-DOSE METRONOMIC CYCLOPHOSPHAMIDE FOR TREATMENT IN PATIENTS WITH LOW GRADE NON-HODGKIN LYMPHOMA

Background: Low-dose metronomic cyclophosphamide chemotherapy is an emerging strategy offering a potentially less toxic yet effective treatment modality. Aims: We evaluated the efficacy and safety of low-dose metronomic cyclophosphamide in patients with low grade non-Hodgkin lymphoma (NHL) by retrospectively reviewing the data. Methods: The patients received oral cyclophosphamide (50 mg per day) and/or oral methotrexate (2.5 mg twice weekly) until disease progression or unacceptable toxicity was noted. Results: Of the 36 patients, 17 (47.2%) were male, median age was 66.4 years (range, 37-91 years), and subtypes of NHL were mucosa associated lymphoid tissue lymphoma (55.6%), small lymphocytic lymphoma (13.9%), follicular lymphoma (11.1%), mantle cell lymphoma (8.3%), nodal marginal zone lymphoma (4.5%), splenic marginal zone lymphoma (2.8%), and lymphoplasmacytic lymphoma (2.8%). The stage I, II, III, IV were 38.9%, 13.9%, 11.1%, 36.1%, respectively and 55.6% of patients received this regimen as the first-line treatment, mainly due to frailty, refusal to standard chemotherapy. The overall best response rate (ORR) was 73.5% (12 complete responses, CRs and 13 partial responses, PRs), with 29.1 months of the median duration of response and the disease control rate was 88.2%. The median treatment duration was 8.8 months (range, 0.1-38.4 months); the median progression-free survival (PFS) was 43.5 months, and the median overall survival (OS) was not yet reached. Especially, the ORR in patients who were treated with metronomic cyclophosphamide as the first line treatment and as more than the second line treatment were 78.9% (10 CRs, 5 PRs) and 66.6% (2 CRs, 9 PRs), respectively. The median PFS were not reached in the first line cyclophosphamide treatment group and 26.5 months (range, 5.7-47.2 months) in the other group (p=0.110), and similarly, the median OS were not reached and 64.4 months (0-135.7 months) (p=0.058), respectively. The regimen was generally well tolerated, with small numbers of grade 3-4 toxicities; neutropenia (2%), anemia (3%), thrombocytopenia (3%), fatigue (4%), and anorexia (1%). Summary/Conclusion: We concluded that low-dose metronomic cyclophosphamide represents efficacious and well-tolerated treatment for low-grade NHL patients.

Metronomic Chemotherapy for Advanced Prostate Cancer: A Literature Review.

Metastatic castration-resistant prostate cancer (mCRPC) is the ultimately lethal form of prostate cancer. Docetaxel chemotherapy was the first life-prolonging treatment for mCRPC; however, the standard maximally tolerated dose (MTD) docetaxel regimen is often not considered for patients with mCRPC who are older and/or frail due to its toxicity. Low-dose metronomic chemotherapy (LDMC) is the frequent administration of typically oral and off-patent chemotherapeutics at low doses, which is associated with a superior safety profile and higher tolerability than MTD chemotherapy. We conducted a systematic literature review using the PUBMED, EMBASE, and MEDLINE electronic databases to identify clinical studies that examined the impact of LDMC on patients with advanced prostate cancer. The search identified 30 reports that retrospectively or prospectively investigated LDMC, 29 of which focused on mCRPC. Cyclophosphamide was the most commonly used agent integrated into 27/30 (90%) of LDMC regimens. LDMC resulted in a clinical benefit rate of 56.8 ± 24.5% across all studies. Overall, there were only a few non-hematological grade 3 or 4 adverse events reported. As such, LDMC is a well-tolerated treatment option for patients with mCRPC, including those who are older and frail. Furthermore, LDMC is considered more affordable than conventional mCRPC therapies. However, prospective phase III trials are needed to further characterize the efficacy and safety of LDMC in mCRPC before its use in practice.

CDK12 promotes tumorigenesis but induces vulnerability to therapies inhibiting folate one-carbon metabolism in breast cancer

Cyclin-dependent kinase 12 (CDK12) overexpression is implicated in breast cancer, but whether it has a primary or only a cooperative tumorigenic role is unclear. Here, we show that transgenic CDK12 overexpression in the mouse mammary gland per se is sufficient to drive the emergence of multiple and multifocal tumors, while, in cooperation with known oncogenes, it promotes earlier tumor onset and metastasis. Integrative transcriptomic, metabolomic and functional data reveal that hyperactivation of the serine-glycine-one-carbon network is a metabolic hallmark inherent to CDK12-induced tumorigenesis. Consistently, in retrospective patient cohort studies and in patient-derived xenografts, CDK12-overexpressing breast tumors show positive response to methotrexate-based chemotherapy targeting CDK12-induced metabolic alterations, while being intrinsically refractory to other types of chemotherapy. In a retrospective analysis of hormone receptor-negative and lymph node-positive breast cancer patients randomized in an adjuvant phase III trial to 1-year low-dose metronomic methotrexate-based chemotherapy or no maintenance chemotherapy, a high CDK12 status predicts a dramatic reduction in distant metastasis rate in the chemotherapy-treated vs. not-treated arm. Thus, by coupling tumor progression with metabolic reprogramming, CDK12 creates an actionable vulnerability for breast cancer therapy and might represent a suitable companion biomarker for targeted antimetabolite therapies in human breast cancers.

REDD1 is a determinant of low-dose metronomic doxorubicin-elicited endothelial cell dysfunction through downregulation of VEGFR-2/3 expression

Low-dose metronomic chemotherapy (LDMC) inhibits tumor angiogenesis and growth by targeting tumor-associated endothelial cells, but the molecular mechanism has not been fully elucidated. Here, we examined the functional role of regulated in development and DNA damage responses 1 (REDD1), an inhibitor of mammalian target of rapamycin complex 1 (mTORC1), in LDMC-mediated endothelial cell dysfunction. Low-dose doxorubicin (DOX) treatment induced REDD1 expression in cultured vascular and lymphatic endothelial cells and subsequently repressed the mRNA expression of mTORC1-dependent translation of vascular endothelial growth factor receptor (Vegfr)-2/3, resulting in the inhibition of VEGF-mediated angiogenesis and lymphangiogenesis. These regulatory effects of DOX-induced REDD1 expression were additionally confirmed by loss- and gain-of-function studies. Furthermore, LDMC with DOX significantly suppressed tumor angiogenesis, lymphangiogenesis, vascular permeability, growth, and metastasis in B16 melanoma-bearing wild-type but not Redd1-deficient mice. Altogether, our findings indicate that REDD1 is a crucial determinant of LDMC-mediated functional dysregulation of tumor vascular and lymphatic endothelial cells by translational repression of Vegfr-2/3 transcripts, supporting the potential therapeutic properties of REDD1 in highly progressive or metastatic tumors.

Low-dose metronomic doxorubicin inhibits mobilization and differentiation of endothelial progenitor cells through REDD1-mediated VEGFR-2 downregulation

Low-dose metronomic chemotherapy has been introduced as a less toxic and effective strategy to inhibit tumor angiogenesis, but its anti-angiogenic mechanism on endothelial progenitor cells (EPCs) has not been fully elucidated. Here, we investigated the functional role of regulated in development and DNA damage response 1 (REDD1), an endogenous inhibitor of mTORC1, in low-dose doxorubicin (DOX)-mediated dysregulation of EPC functions. DOX treatment induced REDD1 expression in bone marrow mononuclear cells (BMMNCs) and subsequently reduced mTORC1-dependent translation of endothelial growth factor (VEGF) receptor (Vegfr)-2 mRNA, but not that of the mRNA transcripts for Vegfr-1, epidermal growth factor receptor, and insulin-like growth factor-1 receptor. This selective event was a risk factor for the inhibition of BMMNC differentiation into EPCs and their angiogenic responses to VEGF-A, but was not observed in Redd1-deficient BMMNCs. Low-dose metronomic DOX treatment reduced the mobilization of circulating EPCs in B16 melanoma-bearing wild-type but not Redd1-deficient mice. However, REDD1 overexpression inhibited the differentiation and mobilization of EPCs in both wild-type and Redd1-deficient mice. These data suggest that REDD1 is crucial for metronomic DOX-mediated EPC dysfunction through the translational repression of Vegfr-2 transcript, providing REDD1 as a potential therapeutic target for the inhibition of tumor angiogenesis and tumor progression.

A Randomized Phase II Trial Comparing the Efficacy and Safety of Pioglitazone, Clarithromycin and Metronomic Low-Dose Chemotherapy with Single-Agent Nivolumab Therapy in Patients with Advanced Non-small Cell Lung Cancer Treated in Second or Further Line (ModuLung).

Background: Most non-small cell lung cancers occur in elderly and frequently comorbid patients. Therefore, it is necessary to evaluate the efficacy of biomodulatory active therapy regimen, concertedly interfering with tumor-associated homeostatic pathways to achieve tumor control paralleled by modest toxicity profiles. Patients and Methods: The ModuLung trial is a national, multicentre, prospective, open-label, randomized phase II trial in patients with histologically confirmed stage IIIB/IV squamous (n = 11) and non-squamous non-small cell (n = 26) lung cancer who failed first-line platinum-based chemotherapy. Patients were randomly assigned on a 1:1 ratio to the biomodulatory or control group, treated with nivolumab. Patients randomized to the biomodulatory group received an all-oral therapy consisting of treosulfan 250 mg twice daily, pioglitazone 45 mg once daily, clarithromycin 250 mg twice daily, until disease progression or unacceptable toxicity. Results: The study had to be closed pre-maturely due to approval of immune checkpoint inhibitors (ICi) in first-line treatment. Thirty-seven patients, available for analysis, were treated in second to forth-line. Progression-free survival (PFS) was significantly inferior for biomodulation (N = 20) vs. nivolumab (N = 17) with a median PFS (95% confidence interval) of 1.4 (1.2–2.0) months vs. 1.6 (1.4–6.2), respectively; with a hazard ratio (95% confidence interval) of 1.908 [0.962; 3.788]; p = 0.0483. Objective response rate was 11.8% with nivolumab vs. 5% with biomodulation, median follow-up 8.25 months. The frequency of grade 3–5 treatment related adverse events was 29% with nivolumab and 10% with biomodulation. Overall survival (OS), the secondary endpoint, was comparable in both treatment arms; biomodulation with a median OS (95% confidence interval) of 9.4 (6.0–33.0) months vs. nivolumab 6.9 (4.6–24.0), respectively; hazard ratio (95% confidence interval) of 0.733 [0.334; 1.610]; p = 0.4368. Seventy-five percent of patients in the biomodulation arm received rescue therapy with checkpoint inhibitors. Conclusions: This trial shows that the biomodulatory therapy was inferior to nivolumab on PFS. However, the fact that OS was similar between groups gives rise to the hypothesis that the well-tolerable biomodulatory therapy may prime tumor tissues for efficacious checkpoint inhibitor therapy, even in very advanced treatment lines where poor response to ICi might be expected with increasing line of therapy.

The Impact of Insulin on Low-dose Metronomic Vinorelbine and Mafosfamide in Breast Cancer Cells.

Breast cancer (BC) may be affected by diabetes and anti-diabetic medication, as well as its therapeutic agents. Low-dose metronomic chemotherapy (LDMC) is an available treatment option in BC. We investigated the impact of insulin on low-dose metronomic vinorelbine and mafosfamide in BC cell lines. Human BC cell lines T-47D, MCF-7, MDA-MB-231, BT-549 and non-tumorigenic breast cell line MCF-10A were exposed to 0.01 μg/ml and 10 μg/ml insulin in combination with low-dose metronomic vinorelbine or mafosfamide. The cell viability was determined after 24-72 hours using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Insulin, especially at a concentration of 10 μg/ml, seemed to increase viability of vinorelbine-treated hormone receptor-positive BC cells, whereas low-dose mafosfamide treatment tended to be potentiated by insulin in triple-negative cells. Our findings suggest that insulin may influence the cytotoxic activity of LDMC depending on insulin concentration, type of cytotoxic drug used and BC cell line.

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

Simple SummaryColorectal cancer is one of the most frequent types of cancer world-wide, leading to over 500,000 cancer-related deaths each year. Although many primary colorectal cancer patients can be cured by surgery, up to 60% will develop metastases. Chemotherapeutic strategies are well-established, but finally often lead to chemo-resistance and tumor relapse. A specific chemotherapeutic approach is low dose metronomic (LDM) therapy, which is based on a constant administration of low doses of a chemotherapeutic compound instead of high-dose pulses, which are often a huge burden for patients and also may induce rapid resistance. However, the molecular mechanism of LDM chemotherapy is not fully understood. Our study therefore aims at identifying gene signatures of colorectal cancer progression under LDM chemotherapy which eventually provides new potential biomarkers for therapeutic interventions.Understanding the molecular signatures of colorectal cancer progression under chemotherapeutic treatment will be crucial for the success of future therapy improvements. Here, we used a xenograft-based mouse model to investigate, how whole transcriptome signatures change during metastatic colorectal cancer progression and how such signatures are affected by LDM chemotherapy using RNA sequencing. We characterized mRNAs as well as non-coding RNAs such as microRNAs, long non-coding RNAs and circular RNAs in colorectal-cancer bearing mice with or without LDM chemotherapy. Furthermore, we found that circZNF609 functions as oncogene, since over-expression studies lead to an increased tumor growth while specific knock down results in smaller tumors. Our data represent novel insights into the relevance of non-coding and circRNAs in colorectal cancer and provide a comprehensive resource of gene expression changes in primary tumors and metastases. In addition, we present candidate genes that could be important modulators for successful LDM chemotherapy.

Abstract 2207: Upfront metronomic chemotherapy synergizes with immunotherapy to optimize chemoimmunotherapy in squamous cell lung carcinoma

Abstract Background and purpose: For squamous cell lung carcinoma (SQCLC), the survival benefits of combining chemotherapy (at the maximum tolerated dose, MTD) with concurrent immune checkpoint inhibitors (ICIs), also known as chemoimmunotherapy, have been confirmed in recent clinical trials. Nevertheless, the actual relationship between MTD chemotherapy and ICIs remains controversial, as most oncologists considered that MTD chemotherapeutic agents could cause immunosuppression. Hence, we attempted to optimize and assess different combinatorial patterns of chemoimmunotherapy in SQCLC. Methods: We utilized the in vitro SQCLC cell lines, in vivo syngeneic immunocompetent mouse models, and patient samples to fully explore how to increase the ectopic lymphoid-like structures (ELSs) and the therapeutic targets for anti-programmed death 1 (PD-1) / anti PD-1 ligand (PD-L1) monoclonal antibodies (mAbs), as well as the underlying mechanisms, in order to render SQCLC to be more sensitive to ICIs and improve the efficacy of chemoimmunotherapy. Results: Low-dose chemotherapeutic agents induced SQCLC cells to undergo immunogenic cell death (ICD) by activating the PI3K/Akt/NF-κB signaling pathway and thereby enhancing neoantigen exposure. Following, the high mobility group box-1 released by cells undergoing ICD promoted neoantigen uptake and presentation by activating dendritic cells (DCs) and consequently invoking specific T cell responses. In vivo, low-dose chemotherapeutic agents activated systemic immune responses and immunological memory, and enhanced antitumor ELSs compared with routine MTD chemotherapy. Moreover, the upfront metronomic (low-dose and frequent administration) chemotherapy extended the time window of the immunostimulatory effect and synergized better with the subsequent administration of anti-PD-1/PD-L1 mAbs. One possible mechanism of this synergy is increasing the activated type I macrophages, DCs, and cytotoxic CD8+ T cells, and maintaining the diversity and normal composition of intestinal gut microbiota. In contrast, when combined with ICIs, the effects of routine MTD chemotherapy appeared to be additive rather than synergistic. Conclusion: The upfront metronomic chemotherapy better synergizes with immunotherapy over the routine MTD chemotherapy in SQCLC. This preclinical study provides a novel strategy to optimize chemoimmunotherapy, and it is worth being translated into the clinic in the future. Citation Format: Xi-Ran He, Yang Du, Yu-Shen Jin, Hua Bai, Jie Tian, Jie Wang. Upfront metronomic chemotherapy synergizes with immunotherapy to optimize chemoimmunotherapy in squamous cell lung carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2207.

Gut Microbiota Profiling in Patients With HER2-Negative Metastatic Breast Cancer Receiving Metronomic Chemotherapy of Capecitabine Compared to Those Under Conventional Dosage.

Purpose: Low-dose metronomic chemotherapy can achieve disease control with reduced toxicity compared to conventional chemotherapy in maximum tolerated dose. Characterizing the gut microbiota of cancer patients under different dosage regimens may describe a new role of gut microbiota associated with drug efficacy. Therefore, we evaluated the composition and the function of gut microbiome associated with metronomic capecitabine compared to conventional dosage.Methods: The fecal samples of HER2-negative metastatic breast cancer patients treated with capecitabine as maintenance chemotherapy were collected and analyzed by 16S ribosome RNA gene sequencing.Results: A total of 15 patients treated with metronomic capecitabine were compared to 16 patients under a conventional dose. The unweighted-unifrac index of the metronomic group was statistically significantly lower than that of the routine group (P = 0.025). Besides that, the Bray–Curtis distance-based redundancy analysis illustrated that the microbial genera between the two groups can be separated partly. Nine Kyoto Encyclopedia of Genes and Genomes (KEGG) modules were enriched in the metronomic group, while no KEGG modules were significantly enriched in the routine group. Moreover, univariate and multivariate analyses suggested that the median progression-free survival (PFS) was significantly shorter in patients with the gut microbial composition of Slackia (9.2 vs. 32.7 months, P = 0.004), while the patients with Blautia obeum had a significantly prolonged PFS than those without (32.7 vs. 12.9 months, P = 0.013).Conclusions: The proof-of-principle study suggested that the gut microbiota of patients receiving metronomic chemotherapy was different in terms of diversity, composition, and function from those under conventional chemotherapy, and the presence of specific bacterial species may act as microbial markers associated with drug resistance monitoring and prognostic evaluation.