Trabectedin Treatment Research Articles

Establishment and characterisation of a new patient-derived model of myxoid liposarcoma with acquired resistance to trabectedin

BackgroundMyxoid liposarcoma is a histological subtype of liposarcoma particularly sensitive to trabectedin. In clinical use this drug does not cause cumulative toxicity, allowing prolonged treatment, generally until disease progression. No other effective therapies are available for trabectedin-resistant patients.MethodsThrough repeated in vivo treatment in athymic nude mice, we have obtained a patient-derived xenograft with acquired resistance to trabectedin.ResultsAt basal level, the morphology of the resistant and sensitive models did not differ, in keeping with the finding that the transcriptional profiles of the resistant and sensitive tumours were very similar. After trabectedin treatment adipogenesis was induced in the parental xenograft but not in the resistant one, as assessed by pathological and molecular analysis. A defective transcription-coupled-nucleotide excision repair in the resistant tumour due to mutation of the UVSSA gene may be implicated in the mechanism of resistance.ConclusionsThis is the first in vivo model of myxoid liposarcoma with acquired resistance to trabectedin. Although further studies are necessary to characterise the resistance mechanisms, this is a useful tool for studying new therapeutic strategies to overcome trabectedin resistance in patients.

Survival and Cost-Effectiveness of Trabectedin Compared to Ifosfamide Monotherapy in Advanced Soft Tissue Sarcoma Patients.

Trabectedin and ifosfamide are among the few cytostatic agents active in advanced soft tissue sarcomas (STSs). Trabectedin is most potent against so-called L-sarcomas (leiomyosarcoma and liposarcoma). The survival gain and cost-effectiveness of these agents in a second-line setting were analysed in the setting of advanced STS after failure of anthracyclines. A prospective observational trial had previously been performed to assess the use of trabectedin in a Dutch real-world setting. Data on ifosfamide monotherapy were acquired from previous studies, and an indirect comparison of survival was made. A state-transition economic model was constructed, in which patients could be in mutually exclusive states of being preprogression, postprogression, or deceased. The costs and quality-adjusted life years (QALYs) for both treatments were assessed from a Dutch health-care perspective. Separate analyses for the group of L-sarcomas and non-L-sarcomas were performed. Trabectedin treatment resulted in a median progression-free survival of 5.2 months for L-sarcoma patients, 2.0 months for non-L-sarcoma patients, and a median overall survival of 11.8 and 6.0 months, respectively. For L-sarcoma patients, trabectedin offered an increase of 0.368 life years and 0.251 QALYs compared to ifosfamide and €20,082 in additional costs, for an incremental cost-effectiveness ratio (ICER) of €80,000 per QALY gained. In the non-L-sarcoma patients, trabectedin resulted in 0.413 less life years and 0.266 less QALYs, at the increased cost of €4,698. The difference in survival between drugs and the acquisition costs of trabectedin were the main influences in these models. Trabectedin was shown to have antitumour efficacy in advanced L-sarcoma. From a health economics perspective, the costs per QALY gained compared to ifosfamide monotherapy that may be acceptable, considering what is currently regarded as acceptable in the Netherlands.

409P - Prognostic factors for post-progression survival after trabectedin treatment in patients with advanced soft tissue sarcoma

409P - Prognostic factors for post-progression survival after trabectedin treatment in patients with advanced soft tissue sarcoma

413P - Clinical benefits of later line trabectedin and eribulin treatment for soft tissue sarcoma (STS) after pazopanib treatment from the Nishinomiya Sarcoma Cohort Study (NSCS)

413P - Clinical benefits of later line trabectedin and eribulin treatment for soft tissue sarcoma (STS) after pazopanib treatment from the Nishinomiya Sarcoma Cohort Study (NSCS)

HMGA1/E2F1 axis and NFkB pathways regulate LPS progression and trabectedin resistance

Although the medical treatments of sarcoma have evolved in the last years, a significant portion of patients develops recurrence after therapies suggesting the need to identify novel targets to improve the treatments. By the use of patient-derived and established cell lines from liposarcoma, as well as specimens from patient biopsies, we found that HMGA1 is involved in the progression of dedifferentiated and myxoid liposarcoma. The immunohistochemical and RT-PCR analyses of 68 liposarcoma specimens revealed a significant high expression of HMGA1, at the protein and RNA levels, both in myxoid and dedifferentiated liposarcoma subtypes compared with differentiated ones. Loss- and gain-of-function experiments by HMGA1-specific depletion and overexpression in dedifferentiated and myxoid liposarcoma cells showed the contribution of this oncogenic factor in cell proliferation, motility, invasion, and drug resistance. The in vitro and in vivo treatment of myxoid liposarcoma with trabectedin, a drug with a potent anti-tumor activity, revealed downregulation of HMGA1, E2F1, and its-downstream targets, vimentin and ZEB1, indicating a critical role of trabectedin in inhibiting the mesenchymal markers of these tumors through the HMGA1/E2F1 axis. These data were also confirmed in patients’ tumor biopsies being HMGA1, E2F1, and vimentin expression significantly reduced upon trabectedin therapy, administered as neo-adjuvant chemotherapy. Furthermore, trabectedin treatment inhibits in vitro NFkB pathway in mixoyd liposarcoma sensitive but not in resistant counterparts, and the inhibition of NFkB pathway re-sensitizes the resistant cells to trabectedin treatment. These data support the rational for combining NFkB inhibitors with trabectedin in liposarcoma patients, who have become resistant to the drug.

Abstract LB-047: Optimizing the trabectedin-mediated inhibition of EWS-FLI1 activity by schedule and fusion type

Abstract BACKGROUND: Ewing sarcoma (ES) is a pediatric malignancy characterized by the EWS-FLI1 transcription factor. ES tumors require the continuous transcriptional activity of EWS-FLI1 for the oncogenic phenotype, regardless of fusion type, which makes EWS-FLI1 an ideal therapeutic target. To date, no EWS-FLI1 directed therapies have been developed. Interestingly, there have been reports of ES patients as exceptional responders in clinical trials, including a complete response in a refractory, metastatic patient that was administered the natural product trabectedin in a Phase I trial. We have since established trabectedin as an EWS-FLI1 inhibitor that acts through a re-localization mechanism at concentrations that are clinically achievable. Intriguingly, trabectedin failed in the Phase II setting after a change in schedule that lead to a decrease in reported Cmax. In this report, we unify the disparate clinical trial conclusions by examining the schedule-dependency of trabectedin in ES cells. METHODS: Here, we model a broad range of exposures to trabectedin and investigate the cell viability kinetics using live cell imaging analysis software and traditional MTS. In parallel, we present a novel assay to quantitatively measure the kinetics of drug clearance in vitro. In addition, we use qPCR and western blotting to examine EWS-FLI1 target gene expression changes in response to different exposures to trabectedin. Finally, we investigated ES cell lines containing variant EWS-FLI1 fusion types and identify an increased sensitivity of type III/IV ES cell lines to trabectedin treatment. We recapitulated these findings in vivo using ES xenograft models. RESULTS: Sensitivity of ES cells to trabectedin treatment is schedule-dependent. Here, we demonstrate that cells treated with trabectedin at equivalent exposures but different Cmax exhibit profound differences in cell viability. The differences in viability correlate with Cmax that are necessary to inhibit EWS-FLI1 activity in vitro. By measuring the kinetics of drug clearance, we show that the inhibitory effects on EWS-FLI1 are durable even after trabectedin has been washed out of the culture medium. In addition, we examine the sensitivity of variant EWS-FLI1 fusion proteins such as type III/IV fusions both in vitro and in vivo. CONCLUSIONS: In this report, we use clinical trial data to develop a more clinically relevant cell culture system for ES drug treatments. Importantly, we demonstrate that equivalent exposures do not lead to equivalent outcomes. We believe that this observation explains the discordant results of the Phase I and II clinical trials, and suggests that the Cmax achieved in serum dictates whether a patient will respond. In addition, we show that type III/IV EWS-FLI1 fusion proteins are particularly sensitive to the drug. Citation Format: Matt Harlow, Elissa Boguslawski, Anderson Peck, Zachary Madaj, Maria J. Navarro, Pablo Aviles, Carlos Galmarini, Patrick Grohar. Optimizing the trabectedin-mediated inhibition of EWS-FLI1 activity by schedule and fusion type [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-047. doi:10.1158/1538-7445.AM2017-LB-047

Efficacy and safety of trabectedin or dacarbazine in patients with advanced uterine leiomyosarcoma after failure of anthracycline-based chemotherapy: Subgroup analysis of a phase 3, randomized clinical trial

ObjectiveTrabectedin demonstrated significantly improved disease control in leiomyosarcoma and liposarcoma patients in a global phase 3 trial (NCT01343277). A post hoc analysis was conducted to assess the efficacy and safety of trabectedin or dacarbazine in women with uterine leiomyosarcoma (uLMS), the largest subgroup of enrolled patients (40%). MethodsOf 577 patients randomized 2:1 to receive trabectedin 1.5mg/m2 by 24-hour IV infusion or dacarbazine 1g/m2 by 20–120-minute IV infusion once every three weeks, 232 had uLMS (trabectedin: 144; dacarbazine: 88). The primary endpoint was overall survival (OS); secondary endpoints were progression-free survival (PFS), objective response rate (ORR), clinical benefit rate (CBR: complete responses+partial responses+stable disease [SD] for at least 18weeks), duration of response (DOR), and safety. ResultsPFS for trabectedin was 4.0months compared with 1.5months for dacarbazine (hazard ratio [HR]=0.57; 95% CI 0.41–0.81; P=0.0012). OS was similar (trabectedin 13.4months vs. dacarbazine 12.9months, HR=0.89; 95% CI 0.65–1.24; P=0.51) between groups. ORR was 11% with trabectedin vs. 9% with dacarbazine (P=0.82). CBR for trabectedin was 31% vs. 18% with dacarbazine (P=0.05); median DOR was 6.5months for trabectedin vs. 4.1months for dacarbazine (P=0.32). Grade 3/4 treatment-emergent adverse events observed in ≥10% of patients in the trabectedin group included transient aminotransferase (aspartate/alanine) elevations, anemia, leukopenia, and thrombocytopenia. ConclusionsIn this post hoc subset analysis of patients with uLMS who had received prior anthracycline therapy, trabectedin treatment resulted in significantly longer PFS versus dacarbazine, with an acceptable safety profile. There was no difference in OS.

Bone Mass Is Compromised by the Chemotherapeutic Trabectedin in Association With Effects on Osteoblasts and Macrophage Efferocytosis.

Macrophages have established roles supporting bone formation. Despite their professional phagocytic nature, the role of macrophage phagocytosis in bone homeostasis is not well understood. Interestingly, apoptosis is a pivotal feature of cellular regulation and the primary fate of osteoblasts is apoptosis. Efferocytosis (phagocytosis of apoptotic cells) is a key physiologic process for the homeostasis of many tissues, and is associated with expression of osteoinductive factors. To test effects of macrophage depletion and compromised phagocytosis on bone, 16-week-old male C57BL/6J mice were treated with trabectedin-a chemotherapeutic with established anti-macrophage effects. Trabectedin treatment reduced F4/80+ and CD68+ macrophages in the bone marrow as assessed by flow cytometry, osteal macrophages near the bone surface, and macrophage viability in vitro. Trabectedin treatment significantly reduced marrow gene expression of key phagocytic factors (Mfge8, Mrc1), and macrophages from treated mice had a reduced ability to phagocytose apoptotic mimicry beads. Macrophages cultured in vitro and treated with trabectedin displayed reduced efferocytosis of apoptotic osteoblasts. Moreover, efferocytosis increased macrophage osteoinductive TGF-β production and this increase was inhibited by trabectedin. Long-term (6-week) treatment of 16-week-old C57BL/6J mice with trabectedin significantly reduced trabecular BV/TV and cortical BMD. Although trabectedin reduced osteoclast numbers in vitro, osteoclast surface in vivo was not altered. Trabectedin treatment reduced serum P1NP as well as MS/BS and BFR/BS, and inhibited mineralization and Runx2 gene expression of osteoblast cultures. Finally, intermittent PTH 1-34 (iPTH) treatment was administered in combination with trabectedin, and iPTH increased trabecular bone volume fraction (BV/TV) in trabectedin-treated mice. Collectively, the data support a model whereby trabectedin significantly reduces bone mass due to compromised macrophages and efferocytosis, but also due to direct effects on osteoblasts. This data has immediate clinical relevance in light of increasing use of trabectedin in oncology. © 2017 American Society for Bone and Mineral Research.

Trabectedin and Campthotecin Synergistically Eliminate Cancer Stem Cells in Cell-of-Origin Sarcoma Models

Trabectedin has been approved for second-line treatment of soft tissue sarcomas. However, its efficacy to target sarcoma initiating cells has not been addressed yet. Here, we used pioneer models of myxoid/round cell liposarcoma (MRCLS) and undifferentiated pleomorphic sarcoma (UPS) developed from transformed human mesenchymal stromal/stem cells (MSCs) to evaluate the effect of trabectedin in the cell type responsible for initiating sarcomagenesis and their derived cancer stem cells (CSC) subpopulations. We found that low nanomolar concentrations of trabectedin efficiently inhibited the growth of sarcoma-initiating cells, induced cell cycle arrest, DNA damage and apoptosis. Interestingly, trabectedin treatment repressed the expression of multiple genes responsible for the development of the CSC phenotype, including pluripotency factors, CSC markers and related signaling pathways. Accordingly, trabectedin induced apoptosis and reduced the survival of CSC-enriched tumorsphere cultures with the same efficiency that inhibits the growth of bulk tumor population. In vivo, trabectedin significantly reduced the mitotic index of MRCLS xenografts and inhibited tumor growth at a similar extent to that observed in doxorubicin-treated tumors. Combination of trabectedin with campthotecin (CPT), a chemotherapeutic drug that shows a robust anti-tumor activity when combined with alkylating agents, resulted in a very strong synergistic inhibition of tumor cell growth and highly increased DNA damage and apoptosis induction. Importantly, the enhanced anti-tumor activity of this combination was also observed in CSC subpopulations. These data suggest that trabectedin and CPT combination may constitute a novel strategy to effectively target both the cell-of-origin and CSC subpopulations in sarcoma.

CLINICAL AND ECONOMIC EVALUATION OF ERIBULIN EFFECTIVENESS IN SOFT TISSUE SARCOMA: RESULTS OF META-ANALYSIS

Innovative drugs eribulin and trabectedin are effective in the treatment of soft tissue sarcomas (STS) – rare, but severe malignancies. Aim of the study . To perform the pharmacoeconomic evaluation of these two agents used with the second and subsequent lines of chemotherapy in common/metastatic STS, in theRussian Federation. Materials and Methods . Direct, indirect and meta-analytic comparisons were applied to the results of two multicenter, randomized phase III clinical studies, on effectiveness and safety of trabectedin and eribulin as compared with dacarbazine for the treatment of severe anthracyclines-resistant lipoand leiomyosarcoms. The 12-month survival rate and the occurrence of adverse events were the endpoint parameters in this study. The impact on the budget and the “cost-effectiveness” index were also analyzed. Results . The relative number of patients, who survived for 12 months and continued their treatment with the given drug, was 53% in the eribulin group, and 18% in the trabectedin group. The total number of recorded adverse events was not significantly different between eribulin and dacarbazine. The incidence of adverse events (including haematological) in the trabectedin group was significantly higher than that in the dacarbazine group (lg 95% CI> 1.0). The cost values of different treatment doses of eribulin got into a zone of 1-2 willingness to pay threshold (WPT). The cost of trabectedin treatment was higher than that of eribulin, and even at mid-optimal doses (1.5 mg/m2 ) exceeded 2xWPT. The cost estimating relationship (CER) was 0.69 for trabectedin, and 0.15 for eribulin. Conclusion . In the Health Care system ofRussia, eribulin has a more favorable pharmaco-economic profile than trabectedin. Since STS is viewed as an orphan disease, both drugs are considered important and promising for the Russian oncological services.

Gene and microRNA modulation upon trabectedin treatment in a human intrahepatic cholangiocarcinoma paired patient derived xenograft and cell line.

Intrahepatic cholangiocarcinoma (ICC) is an aggressive and lethal malignancy with limited therapeutic options. Trabectedin has a high antitumor activity in preclinical models of biliary tract carcinoma (BTC), being a promising alternative treatment. Here, we studied the effect of trabectedin at transcriptomic level on an ICC patient derived xenograft (PDX) and on the derived cell line, MT-CHC01. Further, putative targets of trabectedin were explored in the in vitro model. In vitro, trabectedin inhibited genes involved in protein modification, neurogenesis, migration, and motility; it induced the expression of genes involved in keratinization, tissues development, and apoptotic processes. In the PDX model, trabectedin affected ECM-receptor interaction, focal adhesion, complement and coagulation cascades, Hedgehog, MAPK, EGFR signaling via PIP3 pathway, and apoptosis. Among down-regulated genes, we selected SYK and LGALS1; their silencing caused a significantly reduction of migration, but did not affect proliferation in in vitro models. In MT-CHC01 cells, 24 microRNAs were deregulated upon drug treatment, while only 5 microRNAs were perturbed by trabectedin in PDX. The target prediction analysis showed that SYK and LGALS1 are putative targets of up-regulated microRNAs. In conclusion, we described that trabectedin affected genes and microRNAs involved in tumor progression and metastatic processes, reflecting data previously obtained at macroscopically level; in particular, we identified SYK and LGALS1 as new putative targets of trabectedin.

Metastatic extraskeletal Ewing's sarcoma treated with trabectedin: A case report.

The Ewing's sarcoma family of tumors (ESFT) comprises a number of rare malignant tumors. Standard first-line treatment for patients with these tumors includes chemotherapy with a five-drug regimen of vincristine, doxorubicin (Adriamycin®) and cyclophosphamide, alternating with ifosfamide and etoposide (VAC/IE). In cases of inadequate response, there are a number of second-line regimens available. However, further treatment options are required for those patients with disease unresponsive to standard treatment. Trabectedin is a novel treatment option for patients with ESFT. The present study reports the case of a Caucasian 69-year-old female patient who presented with a soft tissue mass on the chest wall that had developed 7 months earlier. A computed tomography scan revealed a 9×8×7-cm mass on the anterior chest wall above the pectoral muscle. Histopathological evaluations and molecular analysis indicated that it was consistent with a metastatic extraskeletal Ewing's sarcoma. The patient was treated with an alternating VAC/IE regimen; however, an inadequate response was observed. The patient received second-line treatment with a gemcitabine and dacarbazine combination regimen, but the disease progressed. Subsequently, treatment with trabectedin (1.5 mg/m2 as a 24-h continuous infusion every 3 weeks) was initiated. Trabectedin treatment resulted in long-lasting (18 months) progression-free survival. It is vital that novel drugs continue to being developed for patients with ESFT following progression subsequent to standard chemotherapy. The current report presents a case of a patient with metastatic, pre-treated Ewing's sarcoma achieving disease stabilization with trabectedin. Based on these results and the observed tolerability profile, trabectedin represents an alternative treatment for patients with ESFT. Further studies are required in order to determine the efficacy of trabectedin as monotherapy or in combination with other drugs. It is also important to identify which tumor subtypes, specific translocations and patient profiles will benefit the most from treatment with trabectedin.

Abstract LB-177: PM01183 inactivates the EWS/FLI1 transcription factor by redistributing the protein within the nucleus

Abstract BACKGROUND: Ewing sarcoma is a bone and soft tissue sarcoma characterized by fusion of the wild-type EWSR1 and FLI1 genes, which creates a constitutively activated transcription factor, EWS/FLI1. Ewing sarcoma cells are dependent on the continued activity of EWS/FLI1 to block differentiation and promote proliferation. For these reasons, EWS/FLI1 represents an ideal drug target. With this in mind, we have shown that the small molecule trabectedin inhibits EWS/FLI1 activity and synergizes with irinotecan in vivo. In addition, we showed that the gene expression response of Ewing sarcoma cells to trabectedin treatment is identical to keratinocytes exposed to UV light. Interestingly, wild-type EWSR1 accumulates in the nucleolus in response to UV light damage. Therefore, we hypothesize that the response and sensitivity of Ewing sarcoma cells to trabectedin is due to the re-localization of EWS/FLI1 in the nucleus. METHODS: Here, we utilize confocal microscopy and chromatin immunoprecipitation to characterize the localization of EWS/FLI1 and EWS/FLI1 deletion mutants in response to trabectedin. Because trabectedin has a narrow therapeutic index, we characterize the effect of PM01183, a second-generation structural analog with an improved pharmacokinetic profile, on EWS/FLI1 localization. In addition, we use qPCR and western blotting to determine the kinetics of EWS/FLI1 inhibition in response to this class of compounds. W demonstrate the effects of PM01183 treatment on the EWS/FLI1 gene signature genome-wide. Finally, we translate these findings in vivo using two Ewing sarcoma xenograft models. RESULTS: Treatment of Ewing sarcoma cells with Trabectedin and PM01183 causes EWS/FLI1 to accumulate in the nucleolus. This effect is accompanied by a loss of binding at target sequences and a reversal in expression of the gene signature of EWS/FLI1. We found the effect on EWS/FLI1 to be sustained, even after removal of the drug from the cell culture medium. We extended these findings in vivo to demonstrate the efficacy of a previously characterized combination therapy. Interestingly, treatment of Ewing sarcoma xenografts with the combination therapy caused the tumor to be replaced by benign adipocytes. CONCLUSIONS: We characterize a novel method of targeting an oncogenic fusion protein by leveraging a property of the wild-type protein to inactivate the oncogenic transcription factor. We demonstrate that wild-type EWSR1 protein's propensity to accumulate in the nucleolus upon UV light damage is maintained within the oncogenic EWS/FLI1 protein with trabectedin or PM01183 treatment. We believe that this accounts for the heightened sensitivity of Ewing sarcoma cells to this class of compounds and has numerous clinical implications. Citation Format: Matt Harlow, Matthew Easton, Maria Jose Guillén Navarro, Lisa Turner, Galen Hostetter, Carlos Galmarini, Pablo Aviles, Patrick Grohar. PM01183 inactivates the EWS/FLI1 transcription factor by redistributing the protein within the nucleus. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-177.

M1-polarized macrophages as predictor of poor response to trabectedin treatment in myxoid liposarcoma.

e22537Background: Myxoid liposarcoma (MLS) represents a specific subtype of liposarcoma, one of the most common malignant soft tissue tumors affecting adults. Trabectedin is a DNA-binding agent int...

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.

Lack of Correlation Between Liver Tests Abnormalities and Trabectedin Efficacy in the Treatment of Soft Tissue Sarcoma: a Retrospective Study.

Elevation in liver transaminases is common in patients treated with the marine antitumor agent trabectedin. However, the impact of trabectedin-related transaminase elevations on treatment outcomes is unclear. This retrospective study investigated the correlation between liver tests abnormalities and treatment outcomes in patients with unresectable advanced or metastatic soft tissue sarcomas (STS) treated with trabectedin 1.5 mg/m2 once every 3 weeks at three reference centers in Italy. The effect of grade 3/4 elevations in alanine aminotransferase (ALT) or aspartate aminotransferase (AST) during the first two cycles and at any time during trabectedin treatment on progression-free survival (PFS) and overall survival (OS) were analyzed. Liver tests abnormalities during the first two cycles of chemotherapy or at any time during trabectedin treatment did not significantly affect PFS or OS. Nor were survival outcomes significantly different in the subgroups of patients with or without ALT/AST increases or with ALT/AST elevations ≥15 × the upper limit of normal (ULN) versus those with ALT/AST elevation <15 × ULN. Although liver tests abnormalities are common in patients treated with trabectedin, elevations in ALT and AST are usually transient, occur during the first two cycles of treatment, and do not appear to affect survival.

Combined Trabectedin and anti-PD1 antibody produces a synergistic antitumor effect in a murine model of ovarian cancer.

BackgroundMonoclonal antibodies (mAb) that block programmed death (PD)-1 signaling pathway hold great potential as a novel cancer immunotherapy. Recent evidence suggests that combining with conventional, targeted or other immunotherapies, these mAb can induce synergistic antitumor responses. In this study, we investigated whether Trabectedin (ET-743), a novel anticancer agent currently used for treating relapsed ovarian cancer, can synergize with anti (α)-PD-1 mAb to increase antitumor activity in the murine ID8 ovarian cancer model.MethodsMice with established peritoneal ID8 tumor were treated with either single or combined Trabectedin and α-PD-1 mAb, their overall survival was recorded; tumor-associated immune cells and immune gene expression in tumors from treated mice were analyzed by flow cytometry and quantitative RT-PCR, respectively, and antigen-specific immunity of effector CD8+ T cells was evaluated by ELISA and cytotoxicity assay. In addition, the effect of Trabectedin on tumoral PD-L1 expression was analyzed by both flow cytometry and immunofluorescence staining.ResultsThough single treatment showed a modest antitumor effect in mice bearing 10-day-established ID8 tumor, combined Trabectedin and α-PD-1 mAb treatment induced a strong antitumor immune response, leading to a significant tumor regression with half of mice tumor-free 90 days after tumor inoculation. Mechanistic investigation revealed that combination treatment induces a systemic tumor-specific immunity with an indispensable role of both CD4+ and CD8+ T cells, and effector CD8+ T cells exhibited the antigen-specific cytokine secretion and cytotoxicity upon tumor antigen stimulation; additionally, combination treatment increased the IFN-γ-producing effector T cells and decreased the immunosuppressive cells in peritoneal cavity; accordingly, it enhanced the expression of Th1-associated immune-stimulating genes while reducing the transcription of regulatory/suppressive immune genes, reshaping tumor microenvironment from a immunosuppressive to a stimulatory state. Finally, in vivo Trabectedin treatment has been shown to induce IFN-γ-dependent PD-L1 expression within tumor, possibly constituting a mechanistic basis for its synergistic antitumor effect with α-PD-1 mAb therapy.ConclusionThis study provides the evidence that α-PD-1 mAb can produce a synergistic antitumor efficacy when combined with Trabectedin, a clinically available anticancer agent, supporting a direct translation of this combination strategy in clinic for the treatment of ovarian cancer.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-015-0613-y) contains supplementary material, which is available to authorized users.

Beyond clinical trials in advanced soft tissue sarcoma: what to expect from trabectedin treatment? Foreword.

*Department of Interdisciplinary Oncology, HELIOS Klinikum Berlin-Buch, Berlin, Germany; Tel.: +49 30 9401 54801; peter.reichardt@helios-kliniken.de Trabectedin has mechanisms of action that differentiate it from conventional cytotoxic agents used in the treatment of advanced soft tissue sarcoma; the possibility that these multiple mechanisms of action have different roles in different tumors [1] provides opportunity to refine and perhaps even individualize its use. Since trabectedin first became available for clinical investigation in 1995, much has been learned about its unique clinical profile. Some distinguishing characteristics of trabectedin include prolonged tumor control, activity in almost all histological subtypes, positive outcomes in translocation-related sarcoma, maintenance of response, ability to rechallenge after treatment interruption and lack of cumulative toxicity [2]. In this Supplement, evidence for trabectedin is reviewed with the intent of finding answers to some relevant questions regarding its use in clinical practice: Who to treat? When to treat? How to treat? In addition, three clinical case studies provide practical examples of how the characteristics of trabectedin lend themselves to application in diverse settings of advanced soft tissue sarcoma.

A phase IIb multicentre study comparing the efficacy of trabectedin to doxorubicin in patients with advanced or metastatic untreated soft tissue sarcoma: The TRUSTS trial

PurposeTo evaluate whether trabectedin as first-line chemotherapy for advanced/metastatic soft tissue sarcoma prolongs progression-free survival (PFS), compared to doxorubicin and, in the phase IIb part here, to select the most appropriate trabectedin treatment schedule (3-hour or 24-hour infusion) in terms of safety, convenience and efficacy. Patients and methodsIn this randomised multicentre prospective dose-selection phase IIb superiority trial, 133 patients were randomised between doxorubicin (n=43), trabectedin (3-hour infusion, T3h) (n=47) and trabectedin (24-hour infusion, T24h) (n=43). PFS was defined as time from random assignment until objective progression by response evaluation criteria in solid tumours (RECIST 1.1), a global deterioration of the health status requiring discontinuation of the treatment, or death from any cause. ResultsThe study was terminated due to lack of superiority in both trabectedin treatment arms as compared to the doxorubicin control arm. Median PFS was 2.8months in the T3h arm, 3.1months in the T24h arm and 5.5months in the doxorubicin arm. No significant improvements in PFS were observed in the trabectedin arms as compared to the doxorubicin arm (T24h versus doxorubicin: hazard ratio (HR) 1.13, 95% confidence interval (CI) 0.67–1.90, P=.675; T3h versus doxorubicin: HR 1.50, 95% CI 0.91–2.48, P=.944). Only one toxic death occurred in the T3h arm, but treatment had to be stopped due to toxicity in 7 (15.2%) (T3h), 8 (19.5%) (T24h) and 1 (2.5%) doxorubicin patients. ConclusionDoxorubicin continues to be the standard treatment in eligible patients with advanced/metastatic soft-tissue sarcoma (STS). Trabectedin 1.5mg/m2/24-hour infusion is the overall proven approach to delivering this agent in the second-line setting for patients with advanced or metastatic STS.

Targeting Efferocytic M2 Monocytes and Macrophages Offers Therapeutic Promise in Prostate Cancer Skeletal Metastasis

Macrophages play a vital role in maintaining tissue homeostasis through efferocytosis. However, their functional role and pathophysiological contribution to the bone metastatic microenvironment remains unclear. Therefore, we investigated the efferocytic monocyte/macrophage type and its role in supporting PCa bone metastasis. FACS analysis revealed that M2 bone marrow macrophage polarization resulted in increased efferocytosis and pro‐tumorigenic gene expression. Soluble factors released from macrophage efferocytosis increased the PCa cell growth by 30%. Using tumor mouse models, Trabectedin (a chemotherapeutic drug) treatment diminished M2 like macrophages, resulting in decreased tumor metastasis. Clinically, FACS analysis of circulating monocytes isolated from patients with PCa bone metastasis showed a 20% increase in CD68+/CD14+/CD16+ monocytes. Moreover, these phagocytic monocytes presented a 2.5 fold increase in efferocytosis. Tissue analysis revealed high risk PCa tissue expressed significantly higher levels of CD68, which significantly correlated with a high Gleason score. These findings suggest efferocytic M2 like monocytes and macrophages promote prostate cancer bone metastasis.