Anti-inflammatory Properties of the Novel Antitumor Agent Yondelis (Trabectedin): Inhibition of Macrophage Differentiation and Cytokine Production

Newer medical therapies for metastatic soft tissue sarcoma

INTRODUCTION

Metastatic/advanced soft tissue sarcoma has a poor prognosis conventionally, treatment options have been limited. In recent years, this area has been a rich ground for research with many new drugs being approved and several more in the pipeline. With multiple new treatment options available, it is vital to keep up pace with this rapidly changing field. Areas covered: Recent data regarding use of novel agents in advanced soft tissue sarcoma is reviewed with a focus on clinical applicability. The goal is to guide the clinician into choosing appropriate lines of therapy for the individual patient in light of recent availability of multiple new treatment options. Expert commentary: Patients with advanced soft tissue sarcoma can expect to receive several lines of therapy in the modern era. Tumor histology should ideally guide the choice of therapy. The new FDA approved second line drugs viz, trabectedin, pazopanib and eribulin should be considered first after failure of doxorubicin-based chemotherapy. Additional options have become available, such as antiangiogenic agents, mTOR inhibitors, and several new molecules targeting specific oncogenic pathways. All these agents have a role in treating soft tissue sarcoma, and careful individualization of therapy can help achieve optimal outcomes in these challenging patients.

Antitumour activity of trabectedin in myelodysplastic/myeloproliferative neoplasms

BACKGROUND

Juvenile myelomonocytic leukaemia (JMML) and chronic myelomonocytic leukaemia (CMML) are myelodysplastic myeloproliferative (MDS/MPN) neoplasms with unfavourable prognosis and without effective chemotherapy treatment. Trabectedin is a DNA minor groove binder acting as a modulator of transcription and interfering with DNA repair mechanisms; it causes selective depletion of cells of the myelomonocytic lineage. We hypothesised that trabectedin might have an antitumour effect on MDS/MPN.

METHODS

Malignant CD14+ monocytes and CD34+ haematopoietic progenitor cells were isolated from peripheral blood/bone marrow mononuclear cells. The inhibition of CFU-GM colonies and the apoptotic effect on CD14+ and CD34+ induced by trabectedin were evaluated. Trabectedin's effects were also investigated in vitro on THP-1, and in vitro and in vivo on MV-4-11 cell lines.

RESULTS

On CMML/JMML cells, obtained from 20 patients with CMML and 13 patients with JMML, trabectedin - at concentration pharmacologically reasonable, 1-5 nM - strongly induced apoptosis and inhibition of growth of haematopoietic progenitors (CFU-GM). In these leukaemic cells, trabectedin downregulated the expression of genes belonging to the Rho GTPases pathway (RAS superfamily) having a critical role in cell growth and cytoskeletal dynamics. Its selective activity on myelomonocytic malignant cells was confirmed also on in vitro THP-1 cell line and on in vitro and in vivo MV-4-11 cell line models.

CONCLUSIONS

Trabectedin could be good candidate for clinical studies in JMML/CMML patients.

A systems biology approach to investigate the mechanism of action of trabectedin in a model of myelomonocytic leukemia

This study was designed to investigate the mode of action of trabectedin in myelomonocytic leukemia cells by applying systems biology approaches to mine gene expression profiling data and pharmacological assessment of the cellular effects. Significant enrichment was found in regulons of target genes inferred for specific transcription factors, among which MAFB was the most upregulated after treatment and was central in the transcriptional network likely to be relevant for the specific therapeutic effects of trabectedin against myelomonocytic cells. Using the Connectivity Map, similarity among transcriptional signatures elicited by treatment with different compounds was investigated, showing a high degree of similarity between transcriptional signatures of trabectedin and those of the topoisomerase I inhibitor, irinotecan, and an anti-dopaminergic antagonist, thioridazine. The study highlights the potential importance of systems biology approaches to generate new hypotheses that are experimentally testable to define the specificity of the mechanism of action of drugs.

Trabectedin Followed by Irinotecan Can Stabilize Disease in Advanced Translocation-Positive Sarcomas with Acceptable Toxicity

Background. Preclinical data indicate that trabectedin followed by irinotecan has strong synergistic effects on Ewing sarcoma. This is presumably due to hypersensitization of the tumor cells to the camptothecin as an effect of trabectedin in addition to synergistic suppression of EWS-FLI1 downstream targets. A strong effect was also reported in a human rhabdomyosarcoma xenograft. Procedure. Twelve patients with end-stage refractory translocation-positive sarcomas were treated with trabectedin followed by irinotecan within a compassionate use program. Eight patients had Ewing sarcoma and four patients had other translocation-positive sarcomas. Results. Three-month survival rate was 0.75 after the start of this therapy. One patient achieved a partial response according to RECIST criteria, five had stable disease, and the remaining six progressed through therapy. The majority of patients experienced significant hematological toxicity (grades 3 and 4). Reversible liver toxicity and diarrhea also occurred. Conclusions. Our experience with the combination of trabectedin followed with irinotecan in patients with advanced sarcomas showed promising results in controlling refractory solid tumors. While the hematological toxicity was significant, it was reversible. Quality of life during therapy was maintained. These observations encourage a larger clinical trial.

Progression of EGFR-Mutant Lung Adenocarcinoma is Driven By Alveolar Macrophages

PURPOSE

Lung adenocarcinomas with mutations in the EGFR have unprecedented initial responses to targeted therapy against the EGFR. Over time, however, these tumors invariably develop resistance to these drugs. We set out to investigate alternative treatment approaches for these tumors.

EXPERIMENTAL DESIGN

To investigate the immunologic underpinnings of EGFR-mutant lung adenocarcinoma, we utilized a bitransgenic mouse model in which a mutant human EGFR gene is selectively expressed in the lungs.

RESULTS

EGFR oncogene-dependent progression and remission of lung adenocarcinoma was respectively dependent upon the expansion and contraction of alveolar macrophages, and the mechanism underlying macrophage expansion was local proliferation. In tumor-bearing mice, alveolar macrophages downregulated surface expression of MHC-II and costimulatory molecules; increased production of CXCL1, CXCL2, IL1 receptor antagonist; and increased phagocytosis. Depletion of alveolar macrophages in tumor-bearing mice resulted in reduction of tumor burden, indicating a critical role for these cells in the development of EGFR-mutant adenocarcinoma. Treatment of mice with EGFR-targeting clinical drugs (erlotinib and cetuximab) resulted in a significant decrease in alveolar macrophages in these mice. An activated alveolar macrophage mRNA signature was dominant in human EGFR-mutant lung adenocarcinomas, and the presence of this alveolar macrophage activation signature was associated with unfavorable survival among patients undergoing resection for EGFR-mutant lung adenocarcinoma.

CONCLUSIONS

Because of the inevitability of failure of targeted therapy in EGFR-mutant non-small cell lung cancer (NSCLC), these data suggest that therapeutic strategies targeting alveolar macrophages in EGFR-mutant NSCLC have the potential to mitigate progression and survival in this disease. Clin Cancer Res; 23(3); 778-88. ©2016 AACR.

Metabolomics Analysis of Hormone-Responsive and Triple-Negative Breast Cancer Cell Responses to Paclitaxel Identify Key Metabolic Differences

To date, no targeted therapies are available to treat triple negative breast cancer (TNBC), while other breast cancer subtypes are responsive to current therapeutic treatment. Metabolomics was conducted to reveal differences in two hormone receptor-negative TNBC cell lines and two hormone receptor-positive Luminal A cell lines. Studies were conducted in the presence and absence of paclitaxel (Taxol). TNBC cell lines had higher levels of amino acids, branched-chain amino acids, nucleotides, and nucleotide sugars and lower levels of proliferation-related metabolites like choline compared with Luminal A cell lines. In the presence of paclitaxel, each cell line showed unique metabolic responses, with some similarities by type. For example, in the Luminal A cell lines, levels of lactate and creatine decreased while certain choline metabolites and myo-inositol increased with paclitaxel. In the TNBC cell lines levels of glutamine, glutamate, and glutathione increased, whereas lysine, proline, and valine decreased in the presence of drug. Profiling secreted inflammatory cytokines in the conditioned media demonstrated a greater response to paclitaxel in the hormone-positive Luminal cells compared with a secretion profile that suggested greater drug resistance in the TNBC cells. The most significant differences distinguishing the cell types based on pathway enrichment analyses were related to amino acid, lipid and carbohydrate metabolism pathways, whereas several biological pathways were differentiated between the cell lines following treatment.

Trabectedin for Soft Tissue Sarcoma: Current Status and Future Perspectives

Trabectedin (ET743, Yondelis^®, manufactured by Baxter Oncology GmbH, Halle/Westfalen, Germany, for Janssen Products, LP, Horsham, PA), derived from the marine ascidian, Ecteinascidia turbinata, is a natural alkaloid with multiple complex mechanisms of action. On 23 October 2015, 15 years after the results of the first Phase 1 clinical trial using trabectedin for chemotherapy-resistant solid malignancies was reported, and 8 years after its approval in Europe, the United States Food and Drug Administration (USFDA) finally approved trabectedin for the treatment of unresectable or metastatic liposarcoma or leiomyosarcoma that has failed a prior anthracycline-containing regimen. Approval was based on the results of a pivotal Phase 3 trial involving a 2:1 randomization of 518 patients (who were further stratified by soft tissue sarcoma subtype), in which a significant improvement in progression-free survival was reported in the trabectedin-treated group vs. the dacarbazine-treated group (p < 0.001). In this trial, the most common adverse reactions were nausea, fatigue, vomiting, constipation, anorexia, diarrhea, peripheral edema, dyspnea, and headache, while the most serious were neutropenic sepsis, rhabdomyolysis, cardiomyopathy, hepatotoxicity, and extravasation leading to tissue necrosis. The most common grade 3–4 adverse events were laboratory abnormalities of myelosuppression in both arms and transient transaminitis in the trabectedin arm. In a recent Phase 2 trial, trabectedin had a similar outcome as doxorubicin when given as a single agent in the first-line setting. Studies are also being conducted to expand the use of trabectedin not only as a first-line cancer drug, but also for a number of other clinical indications, for example, in the case of mesenchymal chondrosarcoma, for which trabectedin has been reported to be exceptionally active. The possibility of combining trabectedin with targeted therapies, immune checkpoint inhibitors or virotherapy would also be an interesting concept. In short, trabectedin is an old new drug with proven potential to impact the lives of patients with soft tissue sarcoma and other solid malignancies.

Funding: Sarcoma Oncology Center, Santa Monica, CA 90405.

Tumor-associated macrophages and anti-tumor therapies: complex links

Myeloid cells infiltrating the tumor microenvironment, especially tumor-associated macrophages (TAMs), are essential providers of cancer-related inflammation, a condition known to accelerate tumor progression and limit the response to anti-tumor therapies. As a matter of fact, TAMs may have a dual role while interfering with cancer treatments, as they can either promote or impair their functionality. Here we review the connection between macrophages and anticancer therapies; moreover, we provide an overview of the different strategies to target or re-program TAMs for therapeutic purposes.

Hyperthermia adds to trabectedin effectiveness and thermal enhancement is associated with BRCA2 degradation and impairment of DNA homologous recombination repair

The tetrahydroisoquinoline trabectedin is a marine compound with approved activity against human soft-tissue sarcoma. It exerts antiproliferative activity mainly by specific binding to the DNA and inducing DNA double-strand breaks (DSB). As homologous recombination repair (HRR)-deficient tumors are more susceptible to trabectedin, hyperthermia-mediated on-demand induction of HRR deficiency represents a novel and promising strategy to boost trabectedin treatment. For the first time, we demonstrate enhancement of trabectedin effectiveness in human sarcoma cell lines by heat and characterize cellular events and molecular mechanisms related to heat-induced effects. Hyperthermic temperatures (41.8 or 43°C) enhanced significantly trabectedin-related clonogenic cell death and G2/M cell cycle arrest followed by cell type-dependent induction of apoptosis or senescence. Heat combination increased accumulation of γH2AX foci as key marker of DSBs. Expression of BRCA2 protein, an integral protein of the HRR machinery, was significantly decreased by heat. Consequently, recruitment of downstream RAD51 to γH2AX-positive repair foci was almost abolished indicating relevant impairment of HRR by heat. Accordingly, enhancement of trabectedin effectiveness was significantly augmented in BRCA2-proficient cells by hyperthermia and alleviated in BRCA2 knockout or siRNA-transfected BRCA2 knockdown cells. In peripheral blood mononuclear cells isolated from sarcoma patients, increased numbers of nuclear γH2AX foci were detected after systemic treatment with trabectedin and hyperthermia of the tumor region. The findings establish BRCA2 degradation by heat as a key factor for a novel treatment strategy that allows targeted chemosensitization to trabectedin and other DNA damaging antitumor drugs by on-demand induction of HRR deficiency.

Hallmarks of hyperthermia in driving the future of clinical hyperthermia as targeted therapy: translation into clinical application

Regional hyperthermia is described as a targeted therapy and the definitions of six hallmarks of hyperthermia are proposed, representing the pleiotropic effect of this therapeutic modality to counteract tumour growth and progression. We recommend the considerations of these hallmarks in the design of clinical trials involving regional hyperthermia as targeted therapy. Randomised clinical studies using loco-regional hyperthermia as an adjuvant to radiotherapy or to chemotherapy for locally advanced tumours demonstrate the benefit of the combination compared to either of the standard treatments alone for tumour response, disease control, and patient survival outcome. These impressive results were obtained from proof-of-concept trials for superficial or deep-seated malignancies in unselected patients. None of these trials was designed as tailored approaches for the treatment of specified targets or to select potentially more sensitive subpopulations of patients using eligibility criteria. Based upon clinical examples of targeted chemotherapy, some guidelines are described for the successful development of targeted therapeutic combinations. We also retrospectively analyse the stepwise process of generating an ongoing new clinical trial using hyperthermia as targeted therapy to evade DNA repair in combination with a DNA damaging anticancer agent to implement this new vision.

Trabectedin for inoperable or recurrent soft tissue sarcoma in adult patients: a retrospective cohort study

Background

Trabectedin is an antineoplastic agent used for patients with soft tissue sarcoma (STS) who fail standard-of-care treatment. Real-world data of its performance is scarce. This study evaluates the safety and effectiveness of trabectedin for patients with advanced STS who were treated at a high-volume sarcoma center.

Methods

A retrospective chart review was performed on 77 patients treated with trabectedin (24 h infusion q3w) between 01/2005 and 05/2014. Data regarding safety, objective radiological response, progression-free and overall survival were analyzed.

Results

Median age at treatment onset was 52y [interquartile range (IQR): 45-61y]. Tumors included leiomyosarcoma (41.6 %), liposarcoma (18.2 %), and synovial sarcoma (13 %). Trabectedin was provided as ≥ third-line chemotherapy in 71.4 %. Median number of cycles was 2 (range: 1–17). Dose reduction and treatment delays occurred in 19.5 and 40.3 %, respectively. Toxicities occurred in 78 %, primarily for neutropenia or elevated liver enzymes. Two patients died secondary to trabectedin-induced rhabdomyolysis. Treatment was discontinued because of disease progression (84.7 %), toxicity (10 %), and patient preference (5 %). Partial response or stable disease occurred in 14.1 and 33.8 %, respectively, while 52.1 % developed progressive disease. Median progression-free survival was 1.3 m (IQR: 0.7–3.5 m) and was significantly higher in patients lacking severe toxicities or progressive disease. Median overall survival was 6.7 m (IQR: 2.3–12.7 m) and was significantly higher in patients with leiomyosarcoma or liposarcoma relative to other histologies.

Conclusions

Trabectedin has an acceptable safety profile as an anti-tumor agent. Our data further suggest there may be some benefit in using trabectedin particularly in patients with leiomyo- or liposarcoma who failed standard-of-care agents.

Phase II trial of salvage therapy with trabectedin in metastatic pancreatic adenocarcinoma

PURPOSE

No standard salvage chemotherapy has been identified for metastatic pancreatic adenocarcinoma (mPA), and there is an urgent need for active agents against this disease. This phase II trial explored the activity of trabectedin in mPA progressing after gemcitabine-based first-line chemotherapy.

METHODS

Patients with gemcitabine-resistant disease received trabectedin 1.3 mg/m(2) as a 3-h intravenous continuous infusion every 3 weeks until disease progression or unacceptable toxicity or for a maximum of 6 months. The primary endpoint was progression-free survival rate at 6 months (PFS-6). Since trabectedin modulates the production of selected inflammatory mediators, this study also aimed to identify inflammatory biomarkers predictive for response to trabectedin.

RESULTS

Between February 2011 and February 2012, 25 patients received trabectedin. PFS-6 was 4%, median PFS 1.9 months (range 0.8-7.4), and median overall survival 5.2 months (range 1.1-24.3). Grade >2 toxicity consisted of neutropenia in 44% of patients, febrile neutropenia and thrombocytopenia both in 12%, anemia in 8%, fatigue in 12%, and AST and ALT increase in 8 and 4%, respectively. Trabectedin was shown to modulate the production of inflammatory mediators, and at disease progression, levels of a subgroup of cytokines/chemokines were modified. Furthermore, tissue analysis identified 30 genes associated with better prognosis.

CONCLUSIONS

Although it has shown some ability to modulate inflammatory process, single-agent trabectedin had no activity as salvage therapy for mPA.

Depletion of CLL-associated patrolling monocytes and macrophages controls disease development and repairs immune dysfunction in vivo

Chronic lymphocytic leukemia (CLL) is characterized by apoptosis resistance and a dysfunctional immune system. Previous reports suggested a potential role of myeloid cells in mediating these defects. However, the composition and function of CLL-associated myeloid cells have not been thoroughly investigated in vivo. Using the Eμ-TCL1 mouse model, we observed severe skewing of myeloid cell populations with CLL development. Monocytes and M2-like macrophages infiltrated the peritoneal cavity of leukemic mice. Monocytes also accumulated in the spleen in a CCR2-dependent manner, and were severely skewed toward Ly6C(low) patrolling or nonclassical phenotype. In addition, the percentage of MHC-II(hi) dendritic cells and macrophages significantly dropped in the spleen. Gene expression profiling of CLL-associated monocytes revealed aberrantly high PD-L1 expression and secretion of multiple inflammatory and immunosuppressive cytokines like interleukin-10, tumor necrosis factor-α and CXCL9. In vivo myeloid cell depletion using liposomal Clodronate resulted in a significant control of CLL development accompanied by a pronounced repair of innate immune cell phenotypes and a partial resolution of systemic inflammation. In addition, CLL-associated skewing of T cells toward antigen-experienced phenotypes was repaired. The presented data suggest that targeting nonmalignant myeloid cells might serve as a novel immunotherapeutical strategy for CLL.

Inflammation and cancer: advances and new agents

Tumour-promoting inflammation is considered one of the enabling characteristics of cancer development. Chronic inflammatory disease increases the risk of some cancers, and strong epidemiological evidence exists that NSAIDs, particularly aspirin, are powerful chemopreventive agents. Tumour microenvironments contain many different inflammatory cells and mediators; targeting these factors in genetic, transplantable and inducible murine models of cancer substantially reduces the development, growth and spread of disease. Thus, this complex network of inflammation offers targets for prevention and treatment of malignant disease. Much potential exists in this area for novel cancer prevention and treatment strategies, although clinical research to support targeting of cancer-related inflammation and innate immunity in patients with advanced-stage cancer remains in its infancy. Following the initial successes of immunotherapies that modulate the adaptive immune system, we assert that inflammation and innate immunity are important targets in patients with cancer on the basis of extensive preclinical and epidemiological data. The adaptive immune response is heavily dependent on innate immunity, therefore, inhibiting some of the tumour-promoting immunosuppressive actions of the innate immune system might enhance the potential of immunotherapies that activate a nascent antitumour response.

Functional significance of macrophages in pancreatic cancer biology

Pancreatic ductal adenocarcinoma (PDA) is a lethal disease that is usually diagnosed at late stage with few effective therapies. Despite the rapid progress on the genomics and proteomics of the neoplastic cells, therapies that targeted the pancreatic cancer cells proved to be inefficient, which promoted the researchers to turn their attentions to the microenvironment. Currently, various studies had proposed the microenvironment to be a contributing factor for PDA and pervasive researches showed that macrophages within the malignancy correlate with the malignant phenotype of the disease and were reported to a new therapeutic target. Generally, the pro-tumoral effects of macrophages can be summarized as angiogenesis promotion, immunosuppression, matrix remodeling and so on. Hence, a comprehensive understanding of the biologic behaviors of macrophages and their critical role in PDA development may provide new directions for the managements of the lethal disease. In this review, we will summarize the recent advancements on macrophages as pivotal players in PDA biology and the current knowledge about anti-macrophages as a novel strategy against cancer, with the expectation that more efficient therapies will be developed in the near future.

Efficacy and Safety of Trabectedin or Dacarbazine for Metastatic Liposarcoma or Leiomyosarcoma After Failure of Conventional Chemotherapy: Results of a Phase III Randomized Multicenter Clinical Trial

PURPOSE

This multicenter study, to our knowledge, is the first phase III trial to compare trabectedin versus dacarbazine in patients with advanced liposarcoma or leiomyosarcoma after prior therapy with an anthracycline and at least one additional systemic regimen.

PATIENTS AND METHODS

Patients were randomly assigned in a 2:1 ratio to receive trabectedin or dacarbazine intravenously every 3 weeks. The primary end point was overall survival (OS), secondary end points were disease control-progression-free survival (PFS), time to progression, objective response rate, and duration of response-as well as safety and patient-reported symptom scoring.

RESULTS

A total of 518 patients were enrolled and randomly assigned to either trabectedin (n = 345) or dacarbazine (n = 173). In the final analysis of PFS, trabectedin administration resulted in a 45% reduction in the risk of disease progression or death compared with dacarbazine (median PFS for trabectedin v dacarbazine, 4.2 v 1.5 months; hazard ratio, 0.55; P < .001); benefits were observed across all preplanned subgroup analyses. The interim analysis of OS (64% censored) demonstrated a 13% reduction in risk of death in the trabectedin arm compared with dacarbazine (median OS for trabectedin v dacarbazine, 12.4 v 12.9 months; hazard ratio, 0.87; P = .37). The safety profiles were consistent with the well-characterized toxicities of both agents, and the most common grade 3 to 4 adverse effects were myelosuppression and transient elevation of transaminases in the trabectedin arm.

CONCLUSION

Trabectedin demonstrates superior disease control versus conventional dacarbazine in patients who have advanced liposarcoma and leiomyosarcoma after they experience failure of prior chemotherapy. Because disease control in advanced sarcomas is a clinically relevant end point, this study supports the activity of trabectedin for patients with these malignancies.

A comprehensive safety evaluation of trabectedin and drug-drug interactions of trabectedin-based combinations

Trabectedin (Yondelis(®)) is a potent marine-derived antineoplastic drug with high activity against various soft tissue sarcoma (STS) subtypes as monotherapy, and in combination with pegylated liposomal doxorubicin (PLD) for the treatment of patients with relapsed platinum-sensitive ovarian cancer. This article reviews the safety and pharmacokinetic profiles of trabectedin. Records were identified using predefined search criteria using electronic databases (e.g. PubMed, Cochrane Library Database of Systematic Reviews). Primary peer-reviewed articles published between 1 January 2006 and 1 April 2014 were included. The current safety and tolerability profile of trabectedin, based on the evaluation in clinical trials of patients treated with the recommended treatment regimens for STS and recurrent ovarian cancer, was reviewed. Trabectedin as monotherapy or in combination with PLD, was not associated with cumulative and/or irreversible toxicities, such as cardiac, pulmonary, renal, or oto-toxicities, often observed with other common chemotherapeutic agents. The most common adverse drug reactions (ADRs) were myelosuppression and transient hepatic transaminase increases that were usually not clinically relevant. However, trabectedin administration should be avoided in patients with severe hepatic impairment. Serious and fatal ADRs were likely to be related to pre-existing conditions. Doxorubicin or PLD, carboplatin, gemcitabine, or paclitaxel when administered before trabectedin, did not seem to influence its pharmacokinetics. Cytochrome P450 (CYP) 3A4 has an important role in the metabolism of trabectedin, suggesting a risk of drug-drug interactions with trabectedin used in combination with other CYP3A4 substrates. Trabectedin has a favorable risk/efficacy profile, even during extended treatment in pretreated patients.

Management Strategies in Advanced Uterine Leiomyosarcoma: Focus on Trabectedin

The treatment of advanced uterine leiomyosarcomas (U-LMS) represents a considerable challenge. Radiological diagnosis prior to hysterectomy is difficult, with the diagnosis frequently made postoperatively. Whilst a total abdominal hysterectomy is the cornerstone of management of early disease, the role of routine adjuvant pelvic radiotherapy and adjuvant chemotherapy is less clear, since they may improve local tumor control in high risk patients but are not associated with an overall survival benefit. For recurrent or disseminated U-LMS, cytotoxic chemotherapy remains the mainstay of treatment. There have been few active chemotherapy drugs approved for advanced disease, although newer drugs such as trabectedin with its pleiotropic mechanism of actions represent an important addition to the standard front-line systemic therapy with doxorubicin and ifosfamide. In this review, we outline the therapeutic potential and in particular the emerging evidence-based strategy of therapy with trabectedin in patients with advanced U-LMS.

Trabectedin in soft tissue sarcomas

Trabectedin (Yondelis®; PharmaMar, Madrid, Spain), a synthetic anticancer agent originally isolated from the Caribbean tunicate, Ecteinascidia turbinata, is currently approved in more than 70 countries worldwide for the treatment of soft tissue sarcoma (STS). Trabectedin is an isoquinoline alkylating agent that, unlike other alkylating agents, binds in the DNA minor groove to initiate cytotoxic activity. Other multitarget mechanisms of action of trabectedin include important effects within the tumor microenvironment; in particular, trabectedin possesses indirect anti-inflammatory and anti-angiogenic activity via tumor-associated macrophages and high-specificity modulation of various transcription factors. The clinical efficacy of trabectedin, administered intravenously over 24 h every 3 weeks, has been demonstrated in several studies in patients with STS. In the Phase II STS-201 trial, 270 patients with liposarcoma or leiomyosarcoma were randomized to receive trabectedin 1.5 mg/m(2) given as a 24-h intravenous (iv.) infusion every 3 weeks or as a weekly regimen (0.58 mg/m(2); 3-h iv. infusion for three consecutive weeks in a 4-week cycle). There was a statistically significant and clinically relevant 27% reduction in the risk of disease progression (primary end point) with trabectedin given as a 24-h infusion q3w (p = 0.0302) with an overall survival rate at 12 months of 60%. Trabectedin was generally well tolerated; the most frequently reported severe adverse events were neutropenia (47% of patients) and elevated transaminases (47%). Overall, the majority of adverse events were mild to moderate and, despite a long duration of exposure to trabectedin in some patients, no cumulative toxicities were experienced.

Targeting the EWS-FLI1 transcription factor in Ewing sarcoma

PURPOSE

Preclinical data indicate there is strong synergism of action against Ewing sarcoma in sequential treatment with trabectedin followed by irinotecan and it appears to be related to a selective blockade of the transcription factor EWS-FLI1. This combination was evaluated in Ewing sarcoma patient who was progressing with standard therapies.

METHODS

Trabectedin was given as a 24-h iv infusion on day 1 at the dose of 1 mg/sqm, and irinotecan 75 mg/sqm on day 2 and then on days 2 and 4, every 3 weeks from the seventh course.

RESULTS

The therapy was well tolerated with transient hematological toxicity and transaminitis and induced stabilization of the disease lasting for 11 courses, with clinical improvement and marked reduction of the need for opioids. However, shortly before the 12th course, sudden death occurred, possibly due to cerebral stroke, presumably not related to the drug treatment.

CONCLUSIONS

The encouraging clinical benefit observed with the combination and its good tolerability deserves further investigation in Ewing sarcoma.

Trabectedin in patients with advanced soft tissue sarcoma: a retrospective national analysis of the French Sarcoma Group

AIM

The French Sarcoma Group performed this retrospective analysis of the 'RetrospectYon' database with data of patients with recurrent advanced soft tissue sarcoma (STS) treated with trabectedin 1.5 mg/m(2) as a 24-h infusion every three weeks.

METHODS

Patients who achieved non-progressive disease after six initial cycles could receive long-term trabectedin treatment until disease progression.

RESULTS

Overall, 885 patients from 25 French centres were included. Patients received a median of four trabectedin cycles (range: 1-28). The objective response rate was 17% (six complete/127 partial responses) and 50% (n = 403) of patients had stable disease for a disease control rate of 67%. After a median follow-up of 22.0 months, median progression-free survival (PFS) and overall survival (OS) were 4.4 and 12.2 months, respectively. After six cycles, 227/304 patients with non-progressive disease received trabectedin until disease progression and obtained a significantly superior median PFS (11.7 versus 7.6 months, P<0.003) and OS (24.9 versus 16.9 months, P < 0.001) compared with those who stopped trabectedin treatment. Deaths and unscheduled hospitalisation attributed to drug-related events occurred in 0.5% and 9.4% of patients, respectively.

CONCLUSION

The results of this real-life study demonstrate that treatment with trabectedin of patients with STS yielded comparable or improved efficacy outcomes versus those observed in clinical trials. A long-term treatment with trabectedin given until disease progression is associated with significantly improved PFS and OS.

Trabectedin in soft tissue sarcomas

Soft tissue sarcomas are a group of rare tumors derived from mesenchymal tissue, accounting for about 1% of adult cancers. There are over 60 different histological subtypes, each with their own unique biological behavior and response to systemic therapy. The outcome for patients with metastatic soft tissue sarcoma is poor with few available systemic treatment options. For decades, the mainstay of management has consisted of doxorubicin with or without ifosfamide. Trabectedin is a synthetic agent derived from the Caribbean tunicate, Ecteinascidia turbinata. This drug has a number of potential mechanisms of action, including binding the DNA minor groove, interfering with DNA repair pathways and the cell cycle, as well as interacting with transcription factors. Several phase II trials have shown that trabectedin has activity in anthracycline and alkylating agent-resistant soft tissue sarcoma and suggest use in the second- and third-line setting. More recently, trabectedin has shown similar progression-free survival to doxorubicin in the first-line setting and significant activity in liposarcoma and leiomyosarcoma subtypes. Trabectedin has shown a favorable toxicity profile and has been approved in over 70 countries for the treatment of metastatic soft tissue sarcoma. This manuscript will review the development of trabectedin in soft tissue sarcomas.

Dieckol, isolated from the edible brown algae Ecklonia cava, induces apoptosis of ovarian cancer cells and inhibits tumor xenograft growth

PURPOSE

Ecklonia cava is an abundant brown alga and has been reported to possess various bioactive compounds having anti-inflammatory effect. However, the anticancer effects of dieckol, a major active compound in E. cava, are poorly understood. In the present study, we investigated the anti-tumor activity of dieckol and its molecular mechanism in ovarian cancer cells and in a xenograft mouse model .

METHODS

MTT assay, PI staining, and PI and Annexin double staining were performed to study cell cytotoxicity, cell cycle distribution, and apoptosis. We also investigated reactive oxygen species (ROS) production and protein expression using flow cytometry and Western blot analysis, respectively. Anti-tumor effects of dieckol were evaluated in SKOV3 tumor xenograft model.

RESULTS

We found that the E. cava extract and its phlorotannins have cytotoxic effects on A2780 and SKOV3 ovarian cancer cells. Dieckol induced the apoptosis of SKOV3 cells and suppressed tumor growth without any significant adverse effect in the SKOV3-bearing mouse model. Dieckol triggered the activation of caspase-8, caspase-9, and caspase-3, and pretreatment with caspase inhibitors neutralized the pro-apoptotic activity of dieckol. Furthermore, treatment with dieckol caused mitochondrial dysfunction and suppressed the levels of anti-apoptotic proteins. We further demonstrated that dieckol induced an increase in intracellular ROS, and the antioxidant N-acetyl-L-cysteine (NAC) significantly reversed the caspase activation, cytochrome c release, Bcl-2 downregulation, and apoptosis that were caused by dieckol. Moreover, dieckol inhibited the activity of AKT and p38, and overexpression of AKT and p38, at least in part, reversed dieckol-induced apoptosis in SKOV3 cells.

CONCLUSION

These data suggest that dieckol suppresses ovarian cancer cell growth by inducing caspase-dependent apoptosis via ROS production and the regulation of AKT and p38 signaling.

Trabectedin therapy as an emerging treatment strategy for recurrent platinum-sensitive ovarian cancer

Epithelial ovarian cancer (OC) is a common gynecologic malignancy in women. The standard treatment for OC is maximal cytoreductive surgical debulking followed by platinum-based chemotherapy. Despite the high response rate to primary therapy, approximately 85% of patients will develop recurrent ovarian cancer (ROC). This review identifies the clinical use of trabectedin in the treatment algorithm for ROC, with specific emphasis on platinum-sensitive ROC, for which trabectedin in combination with pegylated liposomal doxorubicin has been approved as a treatment protocol. The main mechanisms of action of trabectedin at the cellular level and in the tumor microenvironment is also discussed as bases for identifying biomarkers for selecting patients who may largely benefit from trabectedin-based therapies.

Optimising the treatment of the partially platinum-sensitive relapsed ovarian cancer patient

The choice of second-line chemotherapy in patients with recurrent ovarian cancer (ROC) is complex, with several factors to be considered, the most important of which is the length of the platinum-free treatment interval (PFI). Recently ROC patients have been further stratified into platinum sensitive (PS), partially platinum sensitive (PPS) and platinum resistant (PR) subgroups depending on the length of the PFI. Response to second-line therapy, progression-free survival (PFS) and overall survival (OS) are linked to the PFI, all of them improving as the PFI increases. Consequently, there is increasing interest in PFI extension strategies with platinum-free therapeutic options. Such strategies are currently being studied in patients with partially platinum-sensitive disease (PFI 6-12 months), as the treatment of these patients remains clinically challenging. A non-platinum option, trabectedin + pegylated liposomal doxorubicin (PLD) combination, has been evaluated in ROC patients in the pivotal phase III OVA-301 study. The OVA-301 study differed from previous trials in the same setting as it included only patients who were not expected to benefit from or who were ineligible for or who were unwilling to receive re-treatment with platinum-based chemotherapy, including those with PPS and PR disease. Subset analysis of patients with PPS disease in OVA-301 showed that the trabectedin + PLD combination significantly improved PFS compared with PLD alone; median PFS 7.4 versus 5.5 months, p=0.0152. Final survival data from the same subset of patients, showed that trabectedin + PLD also achieved a significant 36% decrease in the risk of death compared with PLD alone (HR=0.64; 95% CI, 0.47-0.88; p=0.0027). Median overall survival (OS) was 22.4 months in the trabectedin + PLD arm versus 16.4 months in the PLD arm. This represents a statistically significant 6-month improvement in median OS in patients treated with trabectedin + PLD compared to those treated with PLD alone.

Pharmacological treatment for uterine leiomyosarcomas

INTRODUCTION

Pharmacological treatment plays a major role in the management of advanced, persistent or recurrent uterine leiomyosarcoma (LMS), whereas its usefulness in the adjuvant setting is still debated. A thorough literature search was undertaken using the Pubmed databases. Systematic reviews and controlled trials on medical treatment of uterine LMS were collected and critically analyzed. Other study types were secondarily considered when pertinent.

AREAS COVERED

Doxorubicin (DOX), ifosfamide and dacarbazine have been long used in the treatment of this malignancy. Novel active agents are represented by gemcitabine, docetaxel, trabectedin, pazopanib and aromatase inhibitors, whereas the role of eribulin, bevacizumab, aflibercept and mammalian target of rapamycin inhibitors is still investigational.

EXPERT OPINION

DOX alone, gemcitabine alone, DOX + dacarbazine and gemcitabine + docetaxel may be treatment options for first-line and second-line therapies. However, the clinical benefit of the combination chemotherapy versus single-agent chemotherapy is still debated. Trabectedin is a promising agent for recurrent uterine LMS, able to obtain a prolonged disease control, with 3-month and 6-month progression-free survival rates exceeding 50 and 30%, respectively, and with sometimes unexpectedly durable responses. Pazopanib is the only approved targeted therapy. Hormone therapy with aromatase inhibitors may be a therapeutic option in heavily treated patients with slowly progressive, steroid receptor-positive tumors. Whenever possible, women with recurrent uterine LMS should be encouraged to enter well-designed clinical trials aimed to detect novel active agents.

Metabolic orchestration between cancer cells and tumor microenvironment as a co-evolutionary source of chemoresistance in ovarian cancer: a therapeutic implication

Our group reported a significant association between hexokinase II overexpression and chemoresistance in ovarian cancer, suggesting that aerobic glycolysis in the so-called Warburg effect might contribute to cancer progression. However, a growing body of evidence indicates contradictory findings with regard to the Warburg effect, such as high mitochondrial activity in highly invasive tumors and low ATP contribution of glycolysis in ovarian cancer. As a solution for the dilemma of the Warburg effect, the "reverse Warburg effect" was proposed in which aerobic glycolysis might occur in the stromal compartment of the tumor rather than in the cancer cells, indicating that the glycolytic tumor stroma feed the cancer cells through a type of symbiotic relationship. The reverse Warburg effect acting on the relationship between cancer cells and cancer-associated fibroblasts has evolved into dynamic interplay between cancer cells and multiple tumor stromal compartments, including cancer-associated fibroblasts, the extracellular matrix, endothelial cells, mesenchymal stem cells, adipocytes, and tumor-associated macrophages. Peritoneal cavities including ascites and the omentum also form a unique environment that is highly receptive for carcinomatosis in the advanced stages of ovarian cancer. The complicated but ingeniously orchestrated stroma-mediated cancer metabolism in ovarian cancer provides great heterogeneity in tumors with chemoresistance, which makes the disease thus far difficult to cure by single stromal-targeting agents. This review will discuss the experimental and clinical evidence of the cross-talk between cancer cells and various components of tumor stroma in terms of heterogeneous chemoresistance with focal points for therapeutic intervention in ovarian cancer.

Clinical utility of trabectedin for the treatment of ovarian cancer: current evidence

Among the pharmaceutical options available for treatment of ovarian cancer, attention has been increasingly focused on trabectedin (ET-743), a drug which displays a unique mechanism of action and has been shown to be active in several human malignancies. Currently, single agent trabectedin is approved for treatment of patients with advanced soft tissue sarcoma after failure of anthracyclines and ifosfamide, and in association with pegylated liposomal doxorubicin for treatment of patients with relapsed partially platinum-sensitive ovarian cancer. This review aims at summarizing the available evidence about the clinical role of trabectedin in the management of patients with epithelial ovarian cancer. Novel perspectives coming from a better understanding of trabectedin mechanisms of action and definition of patients subgroups likely susceptible to benefit of trabectedin treatment are also presented.

Effect of miR-142-3p on the M2 macrophage and therapeutic efficacy against murine glioblastoma

BACKGROUND

The immune therapeutic potential of microRNAs (miRNAs) in the context of tumor-mediated immune suppression has not been previously described for monocyte-derived glioma-associated macrophages, which are the largest infiltrating immune cell population in glioblastomas and facilitate gliomagenesis.

METHODS

An miRNA microarray was used to compare expression profiles between human glioblastoma-infiltrating macrophages and matched peripheral monocytes. The effects of miR-142-3p on phenotype and function of proinflammatory M1 and immunosuppressive M2 macrophages were determined. The therapeutic effect of miR-142-3p was ascertained in immune-competent C57BL/6J mice harboring intracerebral GL261 gliomas and in genetically engineered Ntv-a mice bearing high-grade gliomas. Student t test was used to evaluate the differences between ex vivo datasets. Survival was analyzed with the log-rank test and tumor sizes with linear mixed models and F test. All statistical tests were two-sided.

RESULTS

miR-142-3p was the most downregulated miRNA (approximately 4.95-fold) in glioblastoma-infiltrating macrophages. M2 macrophages had lower miR-142-3p expression relative to M1 macrophages (P = .03). Overexpression of miR-142-3p in M2 macrophages induced selective modulation of transforming growth factor beta receptor 1, which led to subsequent preferential apoptosis in the M2 subset (P = .01). In vivo miR-142-3p administration resulted in glioma growth inhibition (P = .03, n = 5) and extended median survival (miR-142-3p-treated C57BL/6J mice vs scramble control: 31 days vs 23.5 days, P = .03, n = 10; miR-142-3p treated Ntv-a mice vs scramble control: 32 days vs 24 days, P = .03, n = 9), with an associated decrease in infiltrating macrophages (R (2) = .303).

CONCLUSIONS

These data indicate a unique role of miR-142-3p in glioma immunity by modulating M2 macrophages through the transforming growth factor beta signaling pathway.

Antiangiogenic activity of trabectedin in myxoid liposarcoma: involvement of host TIMP-1 and TIMP-2 and tumor thrombospondin-1

Trabectedin is a marine natural product, approved in Europe for the treatment of soft tissue sarcoma and relapsed ovarian cancer. Clinical and experimental evidence indicates that trabectedin is particularly effective against myxoid liposarcomas where response is associated to regression of capillary networks. Here, we investigated the mechanism of the antiangiogenic activity of trabectedin in myxoid liposarcomas. Trabectedin directly targeted endothelial cells, impairing functions relying on extracellular matrix remodeling (invasion and branching morphogenesis) through the upregulation of the inhibitors of matrix metalloproteinases TIMP-1 and TIMP-2. Increased TIMPs synthesis by the tumor microenvironment following trabectedin treatment was confirmed in xenograft models of myxoid liposarcoma. In addition, trabectedin upregulated tumor cell expression of the endogenous inhibitor thrombospondin-1 (TSP-1, a key regulator of angiogenesis-dependent dormancy in sarcoma), in in vivo models of myxoid liposarcomas, in vitro cell lines and primary cell cultures from patients' myxoid liposarcomas. Chromatin Immunoprecipitation analysis showed that trabectedin displaced the master regulator of adipogenesis C/EBPβ from the TSP-1 promoter, indicating an association between the up-regulation of TSP-1 and induction of adipocytic differentiation program by trabectedin. We conclude that trabectedin inhibits angiogenesis through multiple mechanisms, including directly affecting endothelial cells in the tumor microenvironment--with a potentially widespread activity--and targeting tumor cells' angiogenic activity, linked to a tumor-specific molecular alteration.

Therapeutic strategies for targeting the ovarian tumor stroma

Epithelial ovarian cancer is the most lethal type of gynecologic malignancy. Sixty percent of women who are diagnosed with ovarian cancer present with advanced-stage disease that involves the peritoneal cavity and these patients have a 5-year survival rate of less than 30%. For more than two decades, tumor-debulking surgery followed by platinum-taxane combination chemotherapy has remained the conventional first-line treatment of ovarian cancer. Although the initial response rate is 70%-80%, most patients with advanced-stage ovarian cancer eventually relapse and succumb to recurrent chemoresistant disease. A number of molecular aberrations that drive tumor progression have been identified in ovarian cancer cells and intensive efforts have focused on developing therapeutic agents that target these aberrations. However, increasing evidence indicates that reciprocal interactions between tumor cells and various types of stromal cells also play important roles in driving ovarian tumor progression and that these stromal cells represent attractive therapeutic targets. Unlike tumor cells, stromal cells within the tumor microenvironment are in general genetically stable and are therefore less likely to become resistant to therapy. This concise review discusses the biological significance of the cross-talk between ovarian cancer cells and three major types of stromal cells (endothelial cells, fibroblasts, macrophages) and the development of new-generation therapies that target the ovarian tumor microenvironment.

Trabectedin, a drug acting on both cancer cells and the tumour microenvironment

Trabectedin is the first marine-derived anti-neoplastic drug approved for the treatment of advanced soft tissue sarcoma and, in combination with pegylated liposomal doxorubicin, for the treatment of patients with relapsed platinum-sensitive ovarian cancer. From the beginning of its development, trabectedin showed some peculiar properties that clearly distinguished it from other anti-cancer drugs. In this mini-review, we will outline the current state of knowledge regarding the mode of action of trabectedin, which appears to represent a new class of anti-neoplastic drugs acting both on cancer cells and on the tumour microenvironment.

Heterotypic cellular interactions in the ovarian tumor microenvironment: biological significance and therapeutic implications

The majority of women who are diagnosed with epithelial ovarian cancer present with extensive peritoneal carcinomatosis and are rarely cured by conventional chemotherapy. Ovarian cancer cells typically disseminate by shedding into the peritoneal fluid and implant on the mesothelium-lined peritoneal surfaces that overlie connective and white adipose tissues. Emerging evidence indicates that ovarian tumor progression is orchestrated by dynamic interplay between tumor cells and a variety of stromal cells such as adipocytes, endothelial cells, fibroblasts, mesenchymal stem cells, macrophages, and other immune cells. This mini-review discusses the biological significance of the heterotypic cellular interactions in the ovarian tumor microenvironment and the therapeutic implications of targeting these interactions.

Breaking immunotolerance of tumors: a new perspective for dendritic cell therapy

The use of dendritic cells (DC) in cancer immunotherapy is based on their potent abilities to present antigens, so they can act as 'natural adjuvants' to enhance immunogenicity of tumor antigens and stimulate specific cytotoxic T-cells. Large amounts of DC can be generated from bone marrow, neonatal cord blood, and peripheral blood CD34(+) hematopoietic stem cells, or from peripheral blood monocytes. The DC can then be pulsed with tumor antigens and re-infused. In vitro, antigen-pulsed DC can stimulate allogeneic T-cell proliferation and induction of autologous specific cytotoxic T-cells; in vivo, the cells inhibit the growth of tumors or protect hosts (i.e. mice) from development of inoculated tumors. The results of preliminary clinical trials have shown that DC vaccines are safe and elicit immune responses; however, the rates of clinical responses are low. It has become quite clear that one key reason for unsatisfactory clinical results is tumor-induced immunosuppression. Among the factors contributing to this type of immunosuppression are populations of regulatory cells including: T-regulatory (T(reg)) cells, myeloid-derived suppressor cells (MDSC), tumor-associated macrophages (TAM), and DC expressing 2,3-dioxygenase indoleamine (IDO-DC). This review presents an overview of the current understanding about populations of regulatory cells and the most current research efforts directed to overcome immunosuppressive activity due to the tumor microenvironment.

Trabectedin and plitidepsin: drugs from the sea that strike the tumor microenvironment

The prevailing paradigm states that cancer cells acquire multiple genetic mutations in oncogenes or tumor suppressor genes whose respective activation/up-regulation or loss of function serve to impart aberrant properties, such as hyperproliferation or inhibition of cell death. However, a tumor is now considered as an organ-like structure, a complex system composed of multiple cell types (e.g., tumor cells, inflammatory cells, endothelial cells, fibroblasts, etc.) all embedded in an inflammatory stroma. All these components influence each other in a complex and dynamic cross-talk, leading to tumor cell survival and progression. As the microenvironment has such a crucial role in tumor pathophysiology, it represents an attractive target for cancer therapy. In this review, we describe the mechanism of action of trabectedin and plitidepsin as an example of how these specific drugs of marine origin elicit their antitumor activity not only by targeting tumor cells but also the tumor microenvironment.

Trabectedin for advanced soft tissue sarcomas: a single institution experience

BACKGROUND

We retrospectively analyzed data from patients who had been treated with trabectedin at our institution between April 2009 and August 2011.

PATIENTS & METHODS

Data from 25 patients with recurrent soft tissue sarcoma (leiomyosarcoma: n = 8; liposarcoma: n = 5) were used to assess the efficacy and safety of trabectedin 1.5 mg/m(2) given every 3 weeks.

RESULTS

Most patients (n = 14) had been heavily pretreated with ≥ 2 previous chemotherapy lines. Eight (32%) patients achieved a partial response according to dimensional and tumor density changes, and seven (28%) patients had stable disease for ≥ 3 months (clinical benefit rate = 60%; n = 15). Median progression-free survival was 6.4 months and overall survival 19.3 months. Common adverse events were fatigue, nausea, anemia and transient transaminase increases.

CONCLUSION

Treatment with trabectedin is effective and well tolerated in heavily pretreated soft tissue sarcoma patients. Tapering dexamethasone courses and switching trabectedin administration to an every 4 weeks schedule effectively dealt with persistent fatigue without compromising effectiveness.

Trabectedin mechanism of action: what’s new?

Trabectedin is a tetrahydroisoquinoline molecule that binds to the N2 of guanine in the minor groove, causing DNA damage and affecting transcription regulation in a promoter- and gene-specific manner. The antitumor activity of trabectedin appears to be not only related to its direct effects on cancer cells, but also on the tumor microenvironment. In cancer cells, the drug induces cell cycle arrest and cell death that is not dependent on p53 status, and it is increased dramatically in cells deficient in homologous recombination (e.g., cells with mutations of BRCA1/2). Trabectedin also has potent immunomodulatory effects, being selectively cytotoxic against monocytes and tumor-associated macrophages. In addition, it inhibits production of proinflammatory and angiogenic mediators, which induces changes in the tumor microenvironment and contributes to its antitumor activity. The opportunity to combine direct cytotoxic activity with a capacity to favorably modify the tumor microenvironment, using either single-agent or combination therapy, is an especially appealing therapeutic option for a diverse range of cancers.

Evaluation of the novel USPIO GEH121333 for MR imaging of cancer immune responses

Tumor-associated macrophages (TAM) maintain a chronic inflammation in cancers, which is associated with tumor aggressiveness and poor prognosis. The purpose of this study was to: (1) evaluate the pharmacokinetics and tolerability of the novel ultrasmall superparamagnetic iron oxide nanoparticle (USPIO) compound GEH121333; (2) assess whether GEH121333 can serve as a MR imaging biomarker for TAM; and (3) compare tumor MR enhancement profiles between GEH121333 and ferumoxytol. Blood half-lives of GEH121333 and ferumoxytol were measured by relaxometry (n = 4 each). Tolerance was assessed in healthy rats injected with high dose GEH121333, vehicle or saline (n = 4 each). Animals were monitored for 7 days regarding body weight, complete blood counts and serum chemistry, followed by histological evaluation of visceral organs. MR imaging was performed on mice harboring MMTV-PyMT-derived breast adenocarcinomas using a 7 T scanner before and up to 72 h post-injection (p.i.) of GEH121333 (n = 10) or ferumoxytol (n = 9). Tumor R1, R2* relaxation rates were compared between different experimental groups and time points, using a linear mixed effects model with a random effect for each animal. MR data were correlated with histopathology. GEH121333 showed a longer circulation half-life than ferumoxytol. Intravenous GEH121333 did not produce significant adverse effects in rats. All tumors demonstrated significant enhancement on T1, T2 and T2*-weighted images at 1, 24, 48 and 72 h p.i. GEH121333 generated stronger tumor T2* enhancement than ferumoxytol. Histological analysis verified intracellular compartmentalization of GEH121333 by TAM at 24, 48 and 72 h p.i. MR imaging with GEH121333 nanoparticles represents a novel biomarker for TAM assessment. This new USPIO MR contrast agent provides a longer blood half-life and better TAM enhancement compared with the iron supplement ferumoxytol.

Trabectedin is a feasible treatment for soft tissue sarcoma patients regardless of patient age: a retrospective pooled analysis of five phase II trials

BACKGROUND

This retrospective pooled analysis assessed the effect of age on the efficacy and safety of trabectedin in young and elderly patients with recurrent advanced soft tissue sarcoma (STS).

METHODS

Data from 350 adults with STS treated in five phase II trials with trabectedin were divided in the younger (<60 years; n=267) and the older cohort (≥60 years; n=83).

RESULTS

The response rate did not differ with age (younger: 10.1% vs elderly 9.6%). No significant differences were found in median progression-free survival (PFS) in younger (2.5 months) and older (3.7 months) cohort with a comparable PFS rates at 3 (45.1% vs 55.1%) and 6 months (29.5% vs 36.4%). Similar median overall survival was observed in both cohorts (13.0 vs 14.0 months). Reversible neutropenia and aspartate aminotransferase/alanine aminotransferase elevation were the most common abnormalities. A higher incidence of grade 3/4 neutropenia (43.6% vs 60.2%) and fatigue (6.3% vs 14.4%) was observed in older patients. In 24 patients aged ≥70 years, no significant differences in efficacy or safety outcomes were found.

CONCLUSION

This analysis demonstrated that trabectedin is a feasible treatment in young and elderly patients with STS, with meaningful clinical benefits and an acceptable safety profile, essential in palliative treatment of elderly patients.

Efficacy and safety of trabectedin as an early treatment for advanced or metastatic liposarcoma and leiomyosarcoma

AIMS

We aimed to evaluate the effect of prior chemotherapies on the outcomes of patients with liposarcoma and leiomyosarcoma treated with trabectedin as a 24-h infusion every 3 weeks.

PATIENTS & METHODS

Data from 129 patients who received trabectedin as second-line treatment following failure with an anthracycline/ifosfamide and those who had received at least two lines of prior chemotherapy were analyzed.

RESULTS

Forty seven patients received one prior regimen (group A) and 82 patients received at least two lines of chemotherapy (group B). A favorable trend in median time to progression (4.4 vs 3.0 months), progression-free survival (4.4 vs 2.6 months) and overall survival (17.4 vs 13.3 months) was found in group A. A trend toward higher overall response rate (6.4 vs 4.9%) and disease control rate (34.0 vs 26.8%) also favored group A. Both groups had equivalent safety profiles.

CONCLUSION

All efficacy outcomes were better in patients who received trabectedin as second-line treatment compared with patients with more extensive prior therapy.

Targeting of tumor-associated macrophages made possible by PEG-sheddable, mannose-modified nanoparticles

It is increasingly evident that tumor-associated macrophages (TAMs) play an important role in tumor invasion, proliferation, and metastasis. While delivery of drugs, imaging agents, and vaccines to TAMs was achieved by exploiting membrane receptors on TAMs, the uptake by normal macrophages remains an issue. In this communication, we report a PEG-sheddable, mannose-modified nanoparticle platform that can efficiently target TAMs via mannose-mannose receptor recognition after acid-sensitive PEG shedding in the acidic tumor microenvironment, while their uptake by normal macrophages in the mononuclear phagocyte system (MPS) organs was significantly reduced due to effective PEG shielding at neutral pH. These nanoparticles have the potential to target drugs of interest to TAMs, with decreased uptake by normal macrophages.