Trabectedin therapy for sarcomas

Impact of Pathological Stratification on the Clinical Outcomes of Advanced Well-Differentiated/Dedifferentiated Liposarcoma Treated with Trabectedin

BACKGROUND

We previously showed that grading can prognosticate the outcome of retroperitoneal liposarcoma (LPS). In the present study, we aimed to explore the impact of pathological stratification using grading on the clinical outcomes of patients with advanced well-differentiated LPS (WDLPS) and dedifferentiated LPS (DDLPS) treated with trabectedin.

PATIENTS

We included patients with advanced WDLPS and DDLPS treated with trabectedin at the Fondazione IRCCS Istituto Nazionale dei Tumori between April 2003 and November 2019. Tumors were categorized in WDLPS, low-grade DDLPS, and high-grade DDLPS according to the 2020 WHO classification. Patients were divided in two cohorts: Low-grade (WDLPS/low-grade DDLPS) and high-grade (high-grade DDLPS).

RESULTS

A total of 49 patients were included: 17 (35%) in the low-grade cohort and 32 (65%) in the high-grade cohort. Response rate was 47% in the low-grade cohort versus 9.4% in the high-grade cohort (logistic regression p = 0.006). Median progression-free survival (PFS) was 13.7 months in the low-grade cohort and 3.2 months in the high-grade cohort. Grading was confirmed as an independent predictor of PFS in the Cox proportional-hazards regression multivariable model (adjusted hazard ratio low-grade vs. high-grade: 0.45, 95% confidence interval: 0.22-0.94; adjusted p = 0.035).

CONCLUSIONS

In this retrospective case series, sensitivity to trabectedin was higher in WDLPS/low-grade DDLPS than in high-grade DDLPS. If confirmed in larger series, grading could represent an effective tool to personalize the treatment with trabectedin in patients with advanced LPS.

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.

Parallel lives of symbionts and hosts: chemical mutualism in marine animals

Covering: up to 2018 Symbiotic microbes interact with animals, often by producing natural products (specialized metabolites; secondary metabolites) that exert a biological role. A major goal is to determine which microbes produce biologically important compounds, a deceptively challenging task that often rests on correlative results, rather than hypothesis testing. Here, we examine the challenges and successes from the perspective of marine animal-bacterial mutualisms. These animals have historically provided a useful model because of their technical accessibility. By comparing biological systems, we suggest a common framework for establishing chemical interactions between animals and microbes.

FGFR2 is overexpressed in myxoid liposarcoma and inhibition of FGFR signaling impairs tumor growth in vitro

Myxoid liposarcomas account for more than one third of liposarcomas and about 10% of all adult soft tissue sarcomas. The tumors are characterized by specific chromosomal translocations leading to the chimeric oncogenes FUS-DDIT3 or EWS1R-DDIT3. The encoded fusion proteins act as aberrant transcription factors. Therefore, we implemented comparative expression analyses using whole-genome microarrays in tumor and fat tissue samples. We aimed at identifying differentially expressed genes which may serve as diagnostic or prognostic biomarkers or as therapeutic targets. Microarray analyses revealed overexpression of FGFR2 and other members of the FGF/FGFR family. Overexpression of FGFR2 was validated by qPCR, immunohistochemistry and western blot analysis in primary tumor samples. Treatment of the myxoid liposarcoma cell lines MLS 402 and MLS 1765 with the FGFR inhibitors PD173074, TKI258 (dovitinib) and BGJ398 as well as specific siRNAs reduced cell proliferation, induced apoptosis and delayed cell migration. Combination of FGFR inhibitors with trabectedin further increased the effect. Our study demonstrates overexpression of FGFR2 and a functional role of FGFR signaling in myxoid liposarcoma. As FGFR inhibition showed effects on proliferation and cell migration and induced apoptosis in vitro, our data indicate the potential use of FGFR inhibitors as a targeted therapy for these tumors.

Trabectedin in advanced synovial sarcomas: a multicenter retrospective study from four European institutions and the Italian Rare Cancer Network

Treatment options for patients with metastatic synovial sarcoma are limited. Over recent years, trabectedin has emerged as an effective agent for patients with advanced soft tissue sarcomas resistant to anthracyclines and ifosfamide. The aim of this retrospective analysis was to study the efficacy of trabectedin in the subgroup of synovial sarcomas. A retrospective analysis was carried out on patients with advanced synovial sarcoma treated with trabectedin at four European reference sarcoma centers and within the Italian Rare Cancer Network between 2000 and 2013. Radiological response, progression-free, and overall survival, as well as serious and unexpected adverse events were retrospectively assessed. Sixty-one patients with metastatic synovial sarcoma were identified. The median number of previous chemotherapy regimens was 2 (range 1-6). Nine patients had a partial response, in addition to two minor responses, and 19 patients had stable disease, for an overall response rate of 15% and a tumor control rate of 50%. The median progression-free survival was 3 months, with 23% of patients free from progression at 6 months. The median progression-free survival in responding patients was 7 months. Trabectedin is a therapeutic option for palliative treatment of a subset of patients with metastatic synovial sarcoma.

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.

High-dose continuous-infusion ifosfamide in advanced well-differentiated/dedifferentiated liposarcoma

Background

Liposarcomas represent the most common histological type of soft-tissue sarcomas (STS). Its main subgroups, WD/DD, is known to be poorly sensitive to chemotherapy, with few active agents, i.e., anthracyclines +/- ifosfamide and trabectedin. High-dose ifosfamide (HDIFX >12 g/m2) is active in STS pts pretreated with standard-dose IFX, though with greater toxicity. A prolonged continuous-infusion (ci) through a portable external pump may be an alternative way to administer HDIFX.

Methods

From March 2002 to August 2013, 28 pts (median age =60, range =37–73 yrs) with advanced disease (6 WD and 22 WD/DD) were given ciHDIFX, at the dose of 14 g/m2 as a 14-day continuous infusion every 4 weeks. Twenty-four pts (86%) were previously treated with chemotherapy (19 with anthracyclines and ifosfamide; 4 with anthracycline monotherapy; 1 with trabectedin).

Results

Seven PR (all in DDLPS), 2 minor response (MR) and 11 SD were observed. Of interest, 6 of 9 patients with PR or MR had had SD with the previous therapy with anthracycline plus ifosfamide. The median progression-free survival was 7 months. Most common side effects were mild myelosuppression (anemia G2-3 in 3 pts; G2-3 neutropenia in 3 pts and G4 in 1; G3 thrombocytopenia in 1 pt); nausea (G3 in 3 pts) and fatigue (G3 in 6 pts). One pts had transient G3 confusion.

Conclusions

These data suggest that ciHDIFX is active in WD/DDLPS, even in patients already treated with a combination of anthracyclines plus ifosfamide. In this series, ciHDIFX regimen was better tolerated than HDIFX in published studies.

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.

Myxoid liposarcoma and the mammalian target of rapamycin pathway

PURPOSE OF REVIEW

Myxoid/round cell liposarcoma (MRCL) represents about 10% of all soft-tissue sarcomas. Therapeutic options for this subgroup of tumours are limited, essentially doxorubicin-based regimens and trabectedin. Recently, the mammalian target of rapamycin (mTOR) pathway has been identified as a therapeutic target in several sarcomas. MRCLs should be included among these, as various molecular aberrations of the mTOR pathway have been recently reported.

RECENT FINDINGS

PI3KCA mutations were identified in 10-20% of MRCLs. Other molecular aberrations include loss of PTEN, Akt activation and overexpression of IGF1R. Recently, two minor responses to mTOR inhibitors were reported.

SUMMARY

The relatively high frequency of mTOR signalling pathway alterations in MRCL provides a preclinical rationale for considering mTOR inhibition as a potential novel therapeutic strategy warranting further investigation.

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.

Novel systemic therapies in advanced liposarcoma: a review of recent clinical trial results

Liposarcoma is one of the most common adult soft tissue sarcomas an consists of three histologic subtypes (well and dedifferentiated, myxoid/round cell, and pleomorphic). Surgery is the mainstay of treatment for localized disease; however for unresectable or metastatic disease, effective treatment options are currently limited. In the past decade, a better understanding of the distinct genetic and molecular aberrations for each of the three histologic subtypes has led to the development of several novel systemic therapies. Data from phase I and early phase II clinical trials have been reported. Despite challenges with conducting clinical trials in liposarcoma, preliminary results for several of these novel, biology-driven therapies are encouraging.

Trabectedin in the neoadjuvant treatment of high-grade pleomorphic sarcoma: report of a rare case and literature review

Background. Pleomorphic sarcoma is an aggressive soft tissue sarcoma. In patients with high-risk extremity sarcomas, the significant survival benefits conferred by an intense regimen of neoadjuvant chemoradiotherapy and surgery were reported. To our knowledge, this is the first report in the literature of the neoadjuvant use of trabectedin in a patient with high-grade pleomorphic sarcoma, ineligible for standard neoadjuvant combination therapy with an anthracycline-based regimen. Case Presentation. Here we present a 58-year-old White male with a large tumor in the left thigh, but with no signs of metastases. Owing to the history of severe heart attack, three cycles of neoadjuvant trabectedin were administrated to achieve surgically wide margins. After two cycles, an 18F-FDG-PET showed a large proportion of the central tumor area was without metabolic activity. According to RECIST and Choi criteria, the tumor was stable. After the third cycle of trabectedin, the patient underwent a complete resection, which revealed completely necrotic high-grade pleomorphic sarcoma (stage pT2b), with only a small vital area. Conclusion. The present paper on a promising treatment with neoadjuvant trabectedin of patients with high-grade pleomorphic sarcoma might suggest that such treatment approach may provide a greater chance of cure and survival of such patients.

Role of macrophage targeting in the antitumor activity of trabectedin

There is widespread interest in macrophages as a therapeutic target in cancer. Here, we demonstrate that trabectedin, a recently approved chemotherapeutic agent, induces rapid apoptosis exclusively in mononuclear phagocytes. In four mouse tumor models, trabectedin caused selective depletion of monocytes/macrophages in blood, spleens, and tumors, with an associated reduction of angiogenesis. By using trabectedin-resistant tumor cells and myeloid cell transfer or depletion experiments, we demonstrate that cytotoxicity on mononuclear phagocytes is a key component of its antitumor activity. Monocyte depletion, including tumor-associated macrophages, was observed in treated tumor patients. Trabectedin activates caspase-8-dependent apoptosis; selectivity for monocytes versus neutrophils and lymphocytes is due to differential expression of signaling and decoy TRAIL receptors. This unexpected property may be exploited in different therapeutic strategies.

Extensive adipocytic maturation can be seen in myxoid liposarcomas treated with neoadjuvant doxorubicin and ifosfamide and pre-operative radiation therapy

BACKGROUND

Trabectedin and thioglitazones have been documented to induce adipocytic maturation in myxoid liposarcoma; we have noted this in our experience as well. Intriguingly, we have also encountered this same phenomenon in myxoid liposarcomas exposed to various combinations of neoadjuvant doxorubicin and ifosfamide systemic chemotherapy with preoperative radiation, where the pathological effects have been less characterized. We examined the histological changes, including adipocytic maturation, associated with this treatment in patients with myxoid liposarcoma and evaluated for prognostic significance.

METHODS

Twenty-two patients were identified with histologically confirmed myxoid liposarcomas (9 with variable hypercellular areas) who were treated with neoadjuvant doxorubicin (75-90 mg/m2/continous infusion over 72h every 3 week) and ifosfamide (2.5 g/m2 daily x 4 every 3 weeks) for 4-6 cycles. Twenty-one patients received pre-operative radiation including 5 with concurrent gemcitabine. Pre- and post-treatment MRI studies were compared for changes in tumor area, fat content and contrast uptake, with the latter two estimated as: none, <25%, 25-49% and >50%. Post-treatment specimens were evaluated for hyalinization, necrosis and adipocytic maturation. Clinical follow-up was obtained.

RESULTS

Median age was 45 (26-72) years with a median tumor size of 11 (2-18) cm. All occurred in the lower extremities except for one case in the neck. As is common in myxoid liposarcoma, all had extensive treatment changes (>90%) with extensive hyalinization (n = 16; >90%) or prominent adipocytic maturation (n = 6; >50%) including 2 cases composed almost entirely of mature-appearing adipose tissue. Variable necrosis was identified (5-30%). MRI revealed a decrease in tumor area in all but one tumor (median, 65%), an increase in fat content in 7 tumors (n = 2, >50%;n = 2, 25-50%;n = 3,<25%), and a decrease in contrast enhancement in most tumors (n = 5, >50%; n = 9, 25-49%; n = 7, <25%). Median follow-up was 57 (12-96) months with 17 alive with no disease/metastases, 3 alive with disease and 2 dead of disease. Six patients developed metastases with median interval of 26 (22-51) months post resection. Four of 6 tumors with increased adipocytic maturation >50% on histology had increased fat detected by MRI (>25%). All 6 are alive but 2 developed metastases. In the remaining patients, 4 developed metastases with 14 alive and 2 dead of disease.

CONCLUSION

Myxoid liposarcoma exposed to neoadjuvant doxorubicin and ifosfamide and pre-operative radiation can have prominent adipocytic maturation similar to trabectedin treatment. Myxoid liposarcomas exhibit extensive treatment changes with prominent hyalinization being the most common histological change. Despite this, patients develop metastases regardless of adipocytic maturation. While of unclear significance, no patient with fatty maturation died of disease.

The activities of Smad and Gli mediated signalling pathways in high-grade conventional osteosarcoma

High-grade conventional osteosarcoma is a malignant tumour predominantly affecting adolescents and, despite multimodal intensive therapy, lethal for one third of the patients. Although there is currently detailed knowledge of normal skeletal development, this has not been integrated into research on the genesis of osteosarcoma. Recently we showed that the canonical Wnt pathway is not active in osteosarcoma and that its reactivation is disadvantageous to osteosarcoma cells. Since Wnt is regulating normal skeletogenesis together with other pathways, here we report on the activities of the bone morphogenic protein (BMP), the transforming growth factor beta (TGFβ) and the hedgehog (Hh) pathways in osteosarcoma. Human osteosarcoma samples (n=210), benign bone tumours of osteoblastic lineage called osteoblastoma (n=25) and osteosarcoma cell lines (n=19) were examined. For pathway activity luciferase transcriptional reporter assays and gene and protein expression analyses were performed. Immunohistochemical analysis of phosphorylated Smad1 and Smad2, the intracellular effectors of BMP and TGFβ, respectively, showed nuclear expression of both proteins in 70% of the osteosarcoma samples at levels comparable to osteoblastoma. Interestingly cases with lower expression showed significantly worse disease free survival. This may imply that drugs restoring impaired signalling pathways in osteosarcoma might change the tumour's aggressive clinical course, however targeted pathway modulation in vitro did not affect cell proliferation.

A retrospective analysis of antitumour activity with trabectedin in translocation-related sarcomas

AIMS

Approximately 20% of soft tissue sarcomas (STS) have subtype-specific chromosomal translocations; these generate chimeric oncoproteins which can act as abnormal transcription factors. Since trabectedin can bind to DNA and displace transcription factors, antitumour activity was explored in translocation-related sarcoma (TRS) subtypes.

METHODS

The current retrospective pooled analysis includes data from 81 patients with TRS treated in 8 phase II trials.

RESULTS

TRS subtypes were: synovial sarcoma (SS, n=45), myxoid-round cell liposarcoma (MRC-L-sarcoma, n=27), alveolar soft part sarcoma (ASPS, n=4), endometrial stromal sarcoma (ESS, n=3) and clear cell sarcoma (CCS, n=2). All but one patient had received prior chemotherapy (median of 2 lines). Patients received a median of 4 trabectedin cycles (range, 1-48; median dose intensity=0.40 mg/m(2)/week). Partial responses according to Response Evaluation Criteria in Solid Tumours (RECIST) occurred in 8 patients (ORR=10%; 95% CI, 4-19%): four in MRC-L-sarcoma; three in SS and one in ESS. Tumour control rate (ORR plus stable disease) was 59% (95% CI, 48-70%). Median PFS was 4.1 months (6-month PFS rate=40%). Median overall survival was 17.4 months (survival rate at 12 months=60%). Trabectedin had a manageable safety profile.

CONCLUSION

Trabectedin demonstrates encouraging disease control in TRS. Since these promising results were generally noted in patients following chemotherapy, a phase III randomised trial in first-line is ongoing to compare trabectedin with doxorubicin-based chemotherapy in patients with TRS.

A real time PCR based approach for the quantitative detection of FUS-CHOP fusion transcripts in human liposarcoma

PURPOSE

Histology still forms the backbone for the diagnosis of the myxoid and round cell subtypes of liposarcoma but the molecular identification of the different transcript variants remains a challenge, due, in part, to the complexity of multiple overlapping exons that they share between them. This study was conducted to develop and evaluate a more sensitive platform than existing semi-quantitative approaches for detecting FUS-CHOP transcripts.

MATERIALS AND METHODS

In the present investigation we describe a novel approach using real-time PCR to identify and differentiate the fusion transcripts formed in the t(12; 16)(q13; p11) chromosomal translocation. This method is founded on the basis of transcript individualized primers and probes, which were designed to detect specifically the different variants in both frozen and FFPE tissues.

RESULTS

Our results show that the method is highly specific, sensitive, and superior to the widely used nested PCR approach, and is accurately able to differentiate the most common variants, as well as quantify copy numbers. Primer amplification and probe detection of FUS-CHOP from genomic DNA of human, mouse, cocker spaniel and chicken sources all resulted in completely negative results indicating this technique is specific for human RNA derived transcripts.

CONCLUSION

This new method offers an additional tool in the investigation of liposarcoma that may impact considerably on missed diagnosis and it's accompanying clinical ramifications.

Phase II clinical trial of neoadjuvant trabectedin in patients with advanced localized myxoid liposarcoma

BACKGROUND

To evaluate neoadjuvant trabectedin (1.5 mg/m(2) 24-h i.v. infusion every 3 weeks; three to six cycles) in patients with locally advanced myoxid liposarcoma (ML) previously untreated with chemotherapy or radiation.

PATIENTS AND METHODS

Primary efficacy end point was pathological complete response (pCR) or tumoral regression rate. Objective response according to RECIST (v.1.0) was a secondary end point.

RESULTS

Three of 23 assessable patients had pCR [13%; 95% confidence interval (CI), 3% to 34%]. Furthermore, very good and moderate histological responses were observed in another 2 and 10 patients, respectively. Histological decrement in the cellular and vascular tumor component and maturation of tumor cells to lipoblasts were observed in both myoxid and myoxid/round cell variants. Seven patients had partial response according to RECIST (objective response rate of 24%; 95% CI, 10% to 44%). No disease progression was reported. Neoadjuvant trabectedin was usually well tolerated, with a safety profile similar to that described in patients with soft tissue sarcoma or other tumor types.

CONCLUSION

Trabectedin 1.5 mg/m(2) given as a 24-h i.v. infusion every 3 weeks is a therapeutic option in the neoadjuvant setting of ML.

Appraising the current role of chemotherapy for the treatment of sarcoma

Sarcomas are a heterogeneous group of relatively rare mesenchymal neoplasms. They can be grouped into two general categories: soft tissue sarcoma (STS) and primary bone sarcoma, which are treated differently. Because sarcomas are relatively rare and complex with a wide variety of different histopathologic subtypes, evaluation by multidisciplinary teams who have expertise in the field is recommended. Treatment guidelines for the use of chemotherapy in patients with STS and bone sarcoma have been published by the National Comprehensive Cancer Network. The role of adjuvant chemotherapy in resected STS remains controversial. Although chemotherapy improves disease-free survival, the long-term overall survival benefit remains unproven. Chemotherapy is typically used as palliative treatment for most subtypes of metastatic STS. In contrast, chemotherapy has a proven role in the treatment of primary bone tumors and Ewing sarcoma, but it has not demonstrated efficacy in the treatment of chondrosarcoma. The standard chemotherapy regimens used in sarcoma are associated with significant toxicity, including long-term complications. Less intense and less toxic regimens are the focus of ongoing clinical research. Newer cytotoxic agents with an improved safety profile, such as trabectedin and palifosfamide, are currently in development. Future research needs to focus on identification of subpopulations of patients that are most likely to benefit from chemotherapy.

Trabectedin in patients with advanced non-small-cell lung cancer (NSCLC) with XPG and/or ERCC1 overexpression and BRCA1 underexpression and pretreated with platinum

BACKGROUND

Previous studies in sarcoma found that a composite gene signature, including high expression of nucleotide excision repair (NER) genes (XPG and/or ERCC1) and low expression of homologous recombination repair (HR) genes (BRCA1), identifies a highly sensitive population of patients with significantly improved outcome to trabectedin. This exploratory phase II trial evaluated a customized trabectedin treatment according to this gene signature in patients with non-small cell lung cancer (NSCLC) after the failure of standard platinum-based treatment.

METHODS

Patients were selected according to their mRNA expression (elevated XPG and/or ERCC1, with low BRCA1) using the following values as cutoff: XPG=0.99, ERCC1=3.47 and BRCA1=12.00. Trabectedin was administered as a 1.3mg/m(2) 3-hour intravenous infusion every 3 weeks (q3wk). The primary efficacy endpoint was the progression-free survival rate at 3 months. Objective response according to the Response Evaluation Criteria in Solid Tumors (RECIST) was a secondary efficacy endpoint.

RESULTS

Two of 18 evaluable patients (11.1%; 95% CI, 1.38-34.7%) achieved progression-free survival rate at 3 months. The primary efficacy objective (at least 3 of 18 patients being progression-free at 3 months) was not met, and therefore the trial was early finalized. No objective responses per RECIST were achieved. Four patients had stable disease. Median PFS was 1.3 months, and median overall survival was 5.9 months. Trabectedin was usually well tolerated, with a safety profile similar to that described in patients with other tumor types.

CONCLUSIONS

Customized treatment with trabectedin 1.3mg/m(2) 3-h q3wk according to composite gene signature (XPG and/or ERCC1 overexpression, and BRCA1 underexpression) was well tolerated, but had modest activity in NSCLC patients pretreated with platinum. Therefore, further clinical trials with trabectedin as single agent in this indication are not warranted.

Emerging therapeutic targets for soft tissue sarcoma

Soft tissue sarcomas (STS) are malignancies of mesenchymal origin that represent approximately 1% of cancers in adults. Systematic research into the treatment of STS is challenging given its rarity and disease heterogeneity. Despite the ability to histologically subtype STS, only recently has our approach to therapy begun to differentiate along these lines. The purpose of this review is to highlight emerging therapeutic targets and therapies that hold the potential to add to the current state of systemic treatment for STS.

A phase 2 trial of trabectedin in children with recurrent rhabdomyosarcoma, Ewing sarcoma and non-rhabdomyosarcoma soft tissue sarcomas: a report from the Children's Oncology Group

PURPOSE

To determine the toxicity, efficacy and pharmacokinetics of trabectedin given over 24h every 3 weeks to children with recurrent rhabdomyosarcoma, Ewing sarcoma, or non-rhabdomyosarcoma soft tissue sarcomas.

PATIENTS AND METHODS

Trabectedin was administered as a 24-h intravenous infusion every 21 days. Two dose levels were evaluated (1.3 and 1.5mg/m(2)) for safety; efficacy was then evaluated using a traditional 2-stage design (10+10) at the 1.5mg/m(2) dose level. Pharmacokinetics (day 1 and steady state) were performed during cycle 1.

RESULTS

Fifty patients were enrolled, eight patients at 1.3mg/m(2) and 42 at 1.5mg/m(2). Dose limiting toxicities (DLTs) in the dose finding component included fatigue and reversible GGT elevation in 1/6 evaluable patients at 1.3mg/m(2) and 0/5 at 1.5mg/m(2). Efficacy was evaluated in 42 patients enrolled at the 1.5mg/m(2) dose of whom 22% experienced reversible grade 3 or 4 toxicities that included AST, ALT, or GGT elevations, myelosuppression and deep venous thrombosis. One patient with rhabdomyosarcoma had a partial response and one patient each with rhabdomyosarcoma, spindle cell sarcoma and Ewing sarcoma had stable disease for 2, 3 and 15 cycles, respectively.

CONCLUSION

Trabectedin is safe when administered over 24h at 1.5mg/m(2). Trabectedin did not demonstrate sufficient activity as a single agent for children with relapsed paediatric sarcomas.

Phase 1 clinical trials for sarcomas: the cutting edge

PURPOSE OF REVIEW

Few standard second-line treatment options exist for advanced sarcoma patients. Some of these patients are offered early-phase clinical trials involving targeted or nontargeted agents. This review outlines recent phase 1 trials involving sarcoma patients, explores current challenges and highlights future opportunities in sarcoma developmental therapeutics.

RECENT FINDINGS

New molecularly targeted phase 1 studies have demonstrated efficacy in sarcomas. For instance, insulin-like growth factor-1 receptor (IGF1R) antibodies have produced single agent activity in Ewing's sarcoma. Other promising novel agents include an agonist for the apoptosis ligand 2/tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL) for chondrosarcoma, small molecule inhibitor crizotinib for anaplastic lymphoma kinase (ALK)-rearranged inflammatory myofibroblastic tumor, cedarinib for alveolar soft part sarcoma, and rexin-G, a tumor targeted retrovector for osteosarcoma. In addition, different combinations of chemotherapy in combination with newer agents such as trabectedin exhibited efficacy in advanced soft tissue sarcoma.

SUMMARY

Patients with refractory sarcoma demonstrate benefit from treatment with targeted drugs even in the setting of phase 1 trials. Sarcomas that have a defined translocation and those that express specific activated kinases are particularly promising tumors for targeted therapy. The primary challenge is identifying the biomarkers predictive of response or resistance, matching them with specific patient histology, resulting in successful translation of biology into clinical benefit.

Characterization of a new trabectedin-resistant myxoid liposarcoma cell line that shows collateral sensitivity to methylating agents

Myxoid Liposarcomas (MLS), characterized by the expression of FUS-CHOP fusion gene are clinically very sensitive to the DNA binding antitumor agent, trabectedin. However, resistance eventually occurs, preventing disease eradication. To investigate the mechanisms of resistance, a trabectedin resistant cell line, 402-91/ET, was developed. The resistance to trabectedin was not related to the expression of MDR related proteins, uptake/efflux of trabectedin or GSH levels that were similar in parental and resistant cells. The 402-91/ET cells were hypersensitive to UV light because of a nucleotide excision repair defect: XPG complementation decreased sensitivity to UV rays, but only partially to trabectedin. 402-91/ET cells showed collateral sensitivity to temozolomide due to the lack of O(6) -methylguanine-DNA-methyltransferase (MGMT) activity, related to the hypermethylation of MGMT promoter. In 402-91 cells chromatin immunoprecipitation (ChIP) assays showed that FUS-CHOP was bound to the PTX3 and FN1 gene promoters, as previously described, and trabectedin caused FUS-CHOP detachment from DNA. Here we report that, in contrast, in 402-91/ET cells, FUS-CHOP was not bound to these promoters. Differences in the modulation of transcription of genes involved in different pathways including signal transduction, apoptosis and stress response between the two cell lines were found. Trabectedin activates the transcription of genes involved in the adipogenic-program such as c/EBPα and β, in 402-91 but not in 402-91/ET cell lines. The collateral sensitivity of 402-91/ET to temozolomide provides the rationale to investigate the potential use of methylating agents in MLS patients resistant to trabectedin.

Identification of an inhibitor of the EWS-FLI1 oncogenic transcription factor by high-throughput screening

BACKGROUND

Chromosomal translocations generating oncogenic transcription factors are the hallmark of a variety of tumors, including many sarcomas. Ewing sarcoma family of tumors (ESFTs) are characterized by the t(11;22)(q24;q12) translocation that generates the Ewing sarcoma breakpoint region 1 and Friend leukemia virus integration 1 (EWS-FLI1) fusion transcription factor responsible for the highly malignant phenotype of this tumor. Although continued expression of EWS-FLI1 is believed to be critical for ESFT cell survival, a clinically effective small-molecule inhibitor remains elusive likely because EWS-FLI1 is a transcription factor and therefore widely felt to be "undruggable."

METHODS

We developed a high-throughput screen to evaluate more than 50 000 compounds for inhibition of EWS-FLI1 activity in TC32 ESFT cells. We used a TC32 cell-based luciferase reporter screen using the EWS-FLI1 downstream target NR0B1 promoter and a gene signature secondary screen to sort and prioritize the compounds. We characterized the lead compound, mithramycin, based on its ability to inhibit EWS-FLI1 activity in vitro using microarray expression profiling, quantitative reverse transcription-polymerase chain reaction, and immunoblot analysis, and in vivo using immunohistochemistry. We studied the impact of this inhibition on cell viability in vitro and on tumor growth in ESFT xenograft models in vivo (n = 15-20 mice per group). All statistical tests were two-sided.

RESULTS

Mithramycin inhibited expression of EWS-FLI1 downstream targets at the mRNA and protein levels and decreased the growth of ESFT cells at half maximal inhibitory concentrations between 10 (95% confidence interval [CI] = 8 to 13 nM) and 15 nM (95% CI = 13 to 19 nM). Mithramycin suppressed the growth of two different ESFT xenograft tumors and prolonged the survival of ESFT xenograft-bearing mice by causing a decrease in mean tumor volume. For example, in the TC32 xenograft model, on day 15 of treatment, the mean tumor volume for the mithramycin-treated mice was approximately 3% of the tumor volume observed in the control mice (mithramycin vs control: 69 vs 2388 mm(3), difference = 2319 mm(3), 95% CI = 1766 to 2872 mm(3), P < .001).

CONCLUSION

Mithramycin inhibits EWS-FLI1 activity and demonstrates ESFT antitumor activity both in vitro and in vivo.

Global diversity of Ascidiacea

The class Ascidiacea presents fundamental opportunities for research in the fields of development, evolution, ecology, natural products and more. This review provides a comprehensive overview of the current knowledge regarding the global biodiversity of the class Ascidiacea, focusing in their taxonomy, main regions of biodiversity, and distribution patterns. Based on analysis of the literature and the species registered in the online World Register of Marine Species, we assembled a list of 2815 described species. The highest number of species and families is found in the order Aplousobranchia. Didemnidae and Styelidae families have the highest number of species with more than 500 within each group. Sixty percent of described species are colonial. Species richness is highest in tropical regions, where colonial species predominate. In higher latitudes solitary species gradually contribute more to the total species richness. We emphasize the strong association between species richness and sampling efforts, and discuss the risks of invasive species. Our inventory is certainly incomplete as the ascidian fauna in many areas around the world is relatively poorly known, and many new species continue to be discovered and described each year.

Trabectedin: safety and efficacy in the treatment of advanced sarcoma

Soft tissue sarcomas (STS) are a rare group of malignancies with multiple different subtypes. Close to half of intermediate or high grade STS develop metastatic disease. Treatment of recurrent/metastatic sarcomas is quite challenging with only a few drugs showing measurable benefits. Trabectedin (ecteinascidin 743, ET-743, Yondelis) is a newly developed alkylating agent that has shown significant broad spectrum potential as a single agent second line drug alone or in combination particularly in the treatment of liposarcomas and leiomyosarcomas. Clinical benefit rates seem to favor its use especially in pretreated patients with recurrent/metastatic disease. The drug is well tolerated in general but hepatotoxicity and hematologic side effects are common. Approved in Europe, the currently ongoing Phase III trials along with the already existing clinical evidence may provide enough data for the Food and Drug Administration for an approval in the US.

Anticolon cancer activity of largazole, a marine-derived tunable histone deacetylase inhibitor

Histone deacetylases (HDACs) are validated targets for anticancer therapy as attested by the approval of suberoylanilide hydroxamic acid (SAHA) and romidepsin (FK228) for treating cutaneous T cell lymphoma. We recently described the bioassay-guided isolation, structure determination, synthesis, and target identification of largazole, a marine-derived antiproliferative natural product that is a prodrug that releases a potent HDAC inhibitor, largazole thiol. Here, we characterize the anticancer activity of largazole by using in vitro and in vivo cancer models. Screening against the National Cancer Institute's 60 cell lines revealed that largazole is particularly active against several colon cancer cell types. Consequently, we tested largazole, along with several synthetic analogs, for HDAC inhibition in human HCT116 colon cancer cells. Enzyme inhibition strongly correlated with the growth inhibitory effects, and differential activity of largazole analogs was rationalized by molecular docking to an HDAC1 homology model. Comparative genomewide transcript profiling revealed a close overlap of genes that are regulated by largazole, FK228, and SAHA. Several of these genes can be related to largazole's ability to induce cell cycle arrest and apoptosis. Stability studies suggested reasonable bioavailability of the active species, largazole thiol. We established that largazole inhibits HDACs in tumor tissue in vivo by using a human HCT116 xenograft mouse model. Largazole strongly stimulated histone hyperacetylation in the tumor, showed efficacy in inhibiting tumor growth, and induced apoptosis in the tumor. This effect probably is mediated by the modulation of levels of cell cycle regulators, antagonism of the AKT pathway through insulin receptor substrate 1 down-regulation, and reduction of epidermal growth factor receptor levels.