Trabectedin in myxoid liposarcomas (MLS): a long-term analysis of a single-institution series

Afamitresgene autoleucel for advanced synovial sarcoma and myxoid round cell liposarcoma (SPEARHEAD-1): an international, open-label, phase 2 trial

BACKGROUND

Afamitresgene autoleucel (afami-cel) showed acceptable safety and promising efficacy in a phase 1 trial (NCT03132922). The aim of this study was to further evaluate the efficacy of afami-cel for the treatment of patients with HLA-A*02 and MAGE-A4-expressing advanced synovial sarcoma or myxoid round cell liposarcoma.

METHODS

SPEARHEAD-1 was an open-label, non-randomised, phase 2 trial done across 23 sites in Canada, the USA, and Europe. The trial included three cohorts, of which the main investigational cohort (cohort 1) is reported here. Cohort 1 included patients with HLA-A*02, aged 16-75 years, with metastatic or unresectable synovial sarcoma or myxoid round cell liposarcoma (confirmed by cytogenetics) expressing MAGE-A4, and who had received at least one previous line of anthracycline-containing or ifosfamide-containing chemotherapy. Patients received a single intravenous dose of afami-cel (transduced dose range 1·0 × 109-10·0 × 109 T cells) after lymphodepletion. The primary endpoint was overall response rate in cohort 1, assessed by a masked independent review committee using Response Evaluation Criteria in Solid Tumours (version 1.1) in the modified intention-to-treat population (all patients who received afami-cel). Adverse events, including those of special interest (cytokine release syndrome, prolonged cytopenia, and neurotoxicity), were monitored and are reported for the modified intention-to-treat population. This trial is registered at ClinicalTrials.gov, NCT04044768; recruitment is closed and follow-up is ongoing for cohorts 1 and 2, and recruitment is open for cohort 3.

FINDINGS

Between Dec 17, 2019, and July 27, 2021, 52 patients with cytogenetically confirmed synovial sarcoma (n=44) and myxoid round cell liposarcoma (n=8) were enrolled and received afami-cel in cohort 1. Patients were heavily pre-treated (median three [IQR two to four] previous lines of systemic therapy). Median follow-up time was 32·6 months (IQR 29·4-36·1). Overall response rate was 37% (19 of 52; 95% CI 24-51) overall, 39% (17 of 44; 24-55) for patients with synovial sarcoma, and 25% (two of eight; 3-65) for patients with myxoid round cell liposarcoma. Cytokine release syndrome occurred in 37 (71%) of 52 of patients (one grade 3 event). Cytopenias were the most common grade 3 or worse adverse events (lymphopenia in 50 [96%], neutropenia 44 [85%], leukopenia 42 [81%] of 52 patients). No treatment-related deaths occurred.

INTERPRETATION

Afami-cel treatment resulted in durable responses in heavily pre-treated patients with HLA-A*02 and MAGE-A4-expressing synovial sarcoma. This study shows that T-cell receptor therapy can be used to effectively target solid tumours and provides rationale to expand this approach to other solid malignancies.

FUNDING

Adaptimmune.

Marine-Derived Anticancer Agents Targeting Apoptotic Pathways: Exploring the Depths for Novel Cancer Therapies

Extensive research has been conducted on the isolation and study of bioactive compounds derived from marine sources. Several natural products have demonstrated potential as inducers of apoptosis and are currently under investigation in clinical trials. These marine-derived compounds selectively interact with extrinsic and intrinsic apoptotic pathways using a variety of molecular mechanisms, resulting in cell shrinkage, chromatin condensation, cytoplasmic blebs, apoptotic bodies, and phagocytosis by adjacent parenchymal cells, neoplastic cells, or macrophages. Numerous marine-derived compounds are currently undergoing rigorous examination for their potential application in cancer therapy. This review examines a total of 21 marine-derived compounds, along with their synthetic derivatives, sourced from marine organisms such as sponges, corals, tunicates, mollusks, ascidians, algae, cyanobacteria, fungi, and actinobacteria. These compounds are currently undergoing preclinical and clinical trials to evaluate their potential as apoptosis inducers for the treatment of different types of cancer. This review further examined the compound's properties and mode of action, preclinical investigations, clinical trial studies on single or combination therapy, and the prospective development of marine-derived anticancer therapies.

PDE3A Is a Highly Expressed Therapy Target in Myxoid Liposarcoma

Liposarcomas (LPSs) are a heterogeneous group of malignancies that arise from adipose tissue. Although LPSs are among the most common soft-tissue sarcoma subtypes, precision medicine treatments are not currently available. To discover LPS-subtype-specific therapy targets, we investigated RNA sequenced transcriptomes of 131 clinical LPS tissue samples and compared the data with a transcriptome database that contained 20,218 samples from 95 healthy tissues and 106 cancerous tissue types. The identified genes were referred to the NCATS BioPlanet library with Enrichr to analyze upregulated signaling pathways. PDE3A protein expression was investigated with immunohistochemistry in 181 LPS samples, and PDE3A and SLFN12 mRNA expression with RT-qPCR were investigated in 63 LPS samples. Immunoblotting and cell viability assays were used to study LPS cell lines and their sensitivity to PDE3A modulators. We identified 97, 247, and 37 subtype-specific, highly expressed genes in dedifferentiated, myxoid, and pleomorphic LPS subtypes, respectively. Signaling pathway analysis revealed a highly activated hedgehog signaling pathway in dedifferentiated LPS, phospholipase c mediated cascade and insulin signaling in myxoid LPS, and pathways associated with cell proliferation in pleomorphic LPS. We discovered a strong association between high PDE3A expression and myxoid LPS, particularly in high-grade tumors. Moreover, myxoid LPS samples showed elevated expression levels of SLFN12 mRNA. In addition, PDE3A- and SLFN12-coexpressing LPS cell lines SA4 and GOT3 were sensitive to PDE3A modulators. Our results indicate that PDE3A modulators are promising drugs to treat myxoid LPS. Further studies are required to develop these drugs for clinical use.

Solitary Metastasis to the Breast From Thigh Myxoid Liposarcoma

Metastasis to the breast from non-mammary malignancies are rare and suggestive of advanced disease. Accurate and prompt diagnosis of breast metastasis can provide important prognostic information and guide treatment planning. Interestingly, in contrast to primary breast malignancies, non-mammary metastatic breast lesions often have benign-appearing imaging characteristics. Knowing a patient's clinical history and having prior breast imaging studies for comparison is important for making accurate assessments and appropriate recommendations. Imaging-guided biopsy is often indicated for definitive tissue diagnosis. We report a rare case of solitary metastasis to the breast from thigh myxoid liposarcoma.

Laparoscopic resection of a metastatic myxoid liposarcoma in the mesentery of the small intestine: a case report

BACKGROUND

Myxoid liposarcoma (MLS), with its risk factors, tends to spread to the lungs and extraperitoneally, with intraperitoneal metastases occurring rarely. We present an unusual case of a myxoid liposarcoma that metastasized to the abdominal organs.

CASE PRESENTATION

A 60-year-old female patient was referred to our hospital for the evaluation of a right upper limb tumor that had been growing for 7 years. The patient refused surgery, and during follow-up, tumor hemorrhage resulted in hemorrhagic shock. The patient's right upper limb was immediately amputated. MLS was diagnosed histopathologically. Subsequently, the patient underwent adjuvant chemotherapy. Computed tomography (CT) revealed a right buttock mass, a pelvic mass, and left cardiophrenic angle lymph nodes 3 years after the initial surgery. Contrast-enhanced abdominal CT revealed a relatively low-density, lobulated pelvic tumor. Contrast-enhanced pelvic magnetic resonance imaging (MRI) revealed a low-intensity, lobulated mass on T1-weighted images and a high-intensity mass on T2-weighted images. The pelvic mass showed no significant fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET)-CT. On clinical examination, gynecological malignancies were ruled out as the origin of the pelvic lesions. After resection of the right buttock mass, pelvic mass, and left cardiophrenic angle lymph nodes, the patient underwent laparoscopic surgery for a preoperative diagnosis of small intestinal mesenteric metastasis of MLS. A tumor was found in the mesentery of the small intestine and removed with a margin of 5 cm on both the proximal and distal sides. The specimen measured 10 × 8 × 5 cm and contained a multifocal mass. The tumor was found in the mesentery of the small intestine, with no mucosal or submucosal invasion. The patient was diagnosed with MLS with small mesenteric intestinal metastases. On postoperative day 8, the patient was discharged after an uneventful postoperative course. Twelve months after the surgery, there was no evidence of local or distant recurrence.

CONCLUSIONS

Small intestinal mesenteric metastases of MLSs are rare. Moreover, there are few reports on laparoscopic resection. In this case, the laparoscopic approach was useful in detecting the tumor location and determining the range of resection.

Effectiveness and Safety of Trabectedin and Radiotherapy for Patients With Myxoid Liposarcoma: A Nonrandomized Clinical Trial

Importance

Preclinical data about the synergistic activity of radiotherapy (RT) and trabectedin have been reported. The combination of trabectedin and RT in treating myxoid liposarcomas appears worth exploring.

Objective

To explore the effectiveness and safety of trabectedin combined with RT.

Design, Setting, and Participants

This international, open-label, phase 2 nonrandomized clinical trial including 46 patients with myxoid liposarcoma was conducted in 4 centers in Spain, 1 in Italy, and 2 in France from July 1, 2016, to September 30, 2019. Eligible patients had to have a histologic, centrally reviewed diagnosis of localized resectable myxoid liposarcoma arising from an extremity or the trunk wall.

Interventions

Trabectedin was administered at the recommended dose stemming from the phase 1 trial (1.5 mg/m2), with intravenous infusion during 24 hours every 21 days for a total of 3 cycles. Radiotherapy was started after completion of the first trabectedin infusion (cycle 1, day 2). Patients received 25 fractions of radiation for a total of 45 Gy. Surgery was planned 3 to 4 weeks after the administration of the last preoperative cycle and not until 4 weeks after the end of preoperative RT. Pathologic specimens were mapped in tumor sections to estimate the histologic changes and the percentage of viable tumor after neoadjuvant treatment.

Main Outcomes and Measures

The primary objective of the phase 2 part of the study was overall response. Secondary objectives were effectiveness measured by relapse-free survival and activity measured by functional imaging and pathologic response.

Results

A total of 46 patients were enrolled. Four patients were not evaluable. The median age was 43 years (range, 18-77 years), and 31 patients were male (67%). Overall, 9 of 41 patients (22%) achieved a partial response with neoadjuvant treatment with trabectedin and RT, with 5 of 39 patients (13%) achieving a complete pathologic response and 20 of 39 patients (51%) having 10% or less of a viable remaining tumor. Partial responses according to Choi criteria were observed in 24 of 29 evaluable patients (83%), and no patient had disease progression. Treatment was well tolerated.

Conclusions and Relevance

Although the primary end point of this phase 2 nonrandomized clinical trial was not met (Response Evaluation Criteria in Solid Tumors response in ≥70% of patients), results suggest this combination was well tolerated and effective in terms of pathologic response. Thus, trabectedin plus RT might be a treatment option regarding tolerability; further evidence should be generated in this setting.

Trimodality Treatment of Extremity Soft Tissue Sarcoma: Where Do We Go Now?

OPINION STATEMENT

Extremity soft tissue sarcoma (ESTS) constitutes the majority of patients with soft tissue sarcoma (STS). Patients with localized high-grade ESTS > 5 cm in size carry a substantial risk of developing distant metastasis on follow-up. A neoadjuvant chemoradiotherapy approach can enhance local control by facilitating resection of the large and deep locally advanced tumors while trying to address distant spread by treating the micrometastasis for these high-risk ESTS. Preoperative chemoradiotherapy and adjuvant chemotherapy are often used for children with intermediate- or high-risk non-rhabdomyosarcoma soft tissue tumors in North America and Europe. In adults, the cumulative evidence supporting preoperative chemoradiotherapy or adjuvant chemotherapy remains controversial. However, some studies support a possible benefit of 10% in overall survival (OS) for high-risk localized ESTS, especially for those with a probability of 10-year OS < 60% using validated nomograms. Opponents of neoadjuvant chemotherapy argue that it delays curative surgery, compromises local control, and increases the rate of wound complications and treatment-related mortality; however, the published trials do not support these arguments. Most treatment-related side effects can be managed with adequate supportive care. A coordinated multidisciplinary approach involving sarcoma expertise in surgery, radiation, and chemotherapy is required to achieve better outcomes for ESTS. The next generation of clinical trials will shed light on how comprehensive molecular characterization, targeted agents and/or immunotherapy can be integrated into the upfront trimodality treatment to improve outcomes. To that end, every effort should be made to enroll these patients on clinical trials, when available.

A League of Its Own? Established and Emerging Therapies in Undifferentiated Pleomorphic Sarcoma

OPINION STATEMENT

Over the last decade in soft tissue sarcoma (STS) research, the shifting landscape towards more precise subtype classification and the increasing study of novel therapeutic strategies has prompted a need to highlight current knowledge of effective subtype specific therapies. Undifferentiated pleomorphic sarcoma (UPS), formerly known as malignant fibrous histiocytoma (MFH), is among the most common subtypes of STS arising in the trunk or extremities of adults. Administration of systemic chemotherapy is the primary management in locally advanced and metastatic UPS. While anthracycline-based chemotherapy continues to be standard of care in this setting, outcomes in locally advanced or metastatic UPS remain poor. Recent studies highlight the unique characteristics of UPS that may contribute to its greater sensitivity to immune checkpoint inhibition (ICI) compared to other STS subtypes. With the promise of benefit from novel therapies, including ICI or ICI plus chemotherapy, for a subset of patients with UPS comes the need to identify biomarkers predictive of response to therapy. Ongoing and future clinical trials should place strong emphasis on correlative biomarker studies to learn more about the unique biology of UPS and to identify patients for whom ICI-based therapy will be effective.

Transcription regulators and ultra-rare and other rare translocation-related sarcomas treated with trabectedin: A proof of principle from a post-hoc analysis

Background

Among sarcomas, which are rare cancers with an incidence of <6 per 100.000/year cases, ultra-rare sarcomas have an incidence of approximately ≤1/1,000,000/year cases and altogether account for ~20% of all soft tissue sarcomas (STS) and bone sarcomas. The Italian Sarcoma Group has recently performed a non-interventional, retrospective TrObs study with data from 512 anthracycline-pretreated patients with advanced multiple STS histologies and treated with trabectedin (Palmerini, Cancers 2021; ClinicalTrials.gov Identifier: NCT02793050).

Methods

A post-hoc analysis of case series to evaluate the efficacy and safety of trabectedin on patients with ultra-rare and other rare translocation-related sarcomas included in TrObs study was performed. Main outcomes comprised investigator-assessed overall response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and safety.

Results

Thirty-six patients (18 women) with ultra-rare and other rare sarcoma and a median age of 53.0 years (range: 22-81) were included. Most patients had solitary fibrous tumor (SFT; n=11) followed by epithelioid sarcoma (n=5), malignant peripheral nerve sheath tumor (MPNST; n=4), extraskeletal myxoid chondrosarcoma (EMC; n=3), desmoplastic small round cell tumor (DSRCT; n=3), and alveolar soft part sarcoma (ASPS), rhabdomyosarcoma and clear cell sarcoma (n=2 each). Thirty-five patients had metastatic disease and 23 patients received trabectedin as a second-line treatment. Among 35 patients evaluable for response, two patients with SFT and ASPS had a partial response and one patient with DSRCT obtained a complete response, reaching an ORR of 8.6% (95% CI: 2.8-23.4%). Among patients with an ORR, 6-months PFS was 100% in patients with ASPS, 45.7% in patients with SFT and 33.3% in those with DSRCT. Two patients with epithelioid sarcoma and myoepithelioma had disease stabilization lasting >24 months. Nine patients had at least one grade 3/4 adverse event, mostly being bone marrow toxicity (n=6).

Conclusions

Trabectedin has some anti-tumor activity in some ultra-rare and other rare sarcomas, particularly translocation-related sarcomas, with the well-known manageable safety profile.

Experience with second-line trabectedin in daily clinical practice: case studies

As a recommended second-line option for advanced soft tissue sarcoma, trabectedin can provide the necessary balance between long-term tumor control and preserved quality of life. Three case studies illustrate the long-lasting responses that patients can achieve with second-line trabectedin. A female patient with metastatic leiomyosarcoma maintained disease control for 2 years with trabectedin (× 41 cycles) with excellent tolerability and no relevant adverse events. At the time of writing, a male patient with a metastatic solitary fibrous tumor was asymptomatic after 30 cycles of trabectedin and treatment was ongoing. A young male patient with a recurrent, nonresectable, retroperitoneal myxoid/round cell liposarcoma was able to continue his sporting activities (triathlons) over 2 years with trabectedin (× 14 cycles) plus watchful waiting.

Establishment and characterization of two novel patient-derived myxoid liposarcoma cell lines

Myxoid liposarcoma (MLPS) is a lipogenic sarcoma, characterized by myxoid appearance histology and the presence of the FUS-DDIT3 fusion gene. MLPS shows frequent recurrence and poor prognosis after standard treatments, such as surgery. Therefore, novel therapeutic approaches for MLPS are needed. Development of novel treatments requires patient-derived cell lines to study the drug responses and their molecular backgrounds. Presently, only three cell lines of MLPS have been reported, and no line is available from public cell banks. Thus, this study aimed to establish and characterize novel MLPS cell lines. Using surgically resected tumor tissue from two patients with MLPS, two novel lines NCC-MLPS2-C1 and NCC-MLPS3-C1 were established. The presence of FUS-DDIT3 fusion, slow growth, spheroid formation, and invasive capability in these cell lines was confirmed. Growth retardation was monitored for 213 anti-cancer agents using NCC-MLPS2-C1 and NCC-MLPS3-C1 cells, and the results were integrated with the response to treatments in an MLPS cell line, NCC-MLPS1-C1, which was previously established in our laboratory. We found that romidepsin suppressed cell proliferation at considerably low concentrations in all three examined cell lines. NCC-MLPS2-C1 and NCC-MLPS3-C1 cell lines developed here represent a useful tool for basic and preclinical studies of MLPS.

Trabectedin in Cancers: Mechanisms and Clinical Applications

Trabectedin, a tetrahydroisoquinoline alkaloid, is the first marine antineoplastic agent approved with special anticancer mechanisms involving DNA binding, DNA repair pathways, transcription regulation and regulation of the tumor microenvironment. It has favorable clinical applications, especially for the treatment of patients with advanced soft tissue sarcoma, who failed in anthracyclines and ifosfamide therapy or could not receive these agents. Currently, trabectedin monotherapy regimen and regimens of combined therapy with other agents are both widely used for the treatment of malignancies, including soft tissue sarcomas, ovarian cancer, breast cancer, and non-small-cell lung cancer. In this review, we summarized the basic information and some updated knowledge on trabectedin, including its molecular structure, metabolism in various cancers, pharmaceutical mechanisms, clinical applications, drug combination, and adverse reactions, along with prospections on its possibly more optimal use in cancer treatment.

Overview of systemic therapy options in liposarcoma, with a focus on the activity of selinexor, a selective inhibitor of nuclear export in dedifferentiated liposarcoma

Liposarcoma (LPS) is a common soft tissue sarcoma that encompasses diverse subtypes of well-differentiated/dedifferentiated, myxoid/round cell, and pleomorphic LPS. There is heterogeneity among the various LPS types with regard to prognosis, molecular pathogenesis, and response to treatment. Well-differentiated (WDLPS) and dedifferentiated liposarcoma (DDLPS) are most common types, which share common genetic alteration of chromosome 12q13-15 amplification resulting in amplification of oncogenes, including MDM2 (Mouse double minute 2), CDK4 (cyclin-dependent kinase 4), and HMGA2 (High mobility group protein AT-hook 2). Despite sharing the same molecular alteration, DDLPS has a worse prognosis, with a higher recurrence rate and higher propensity for metastases compared to WDLPS. Here we provide an overview of the LPS treatment landscape focusing on recent developments in the treatment of DDLPS with a focus on selinexor. Selinexor, a selective inhibitor of XPO1, was recently evaluated in a phase 3 trial, the first prospective randomized trial in DDLPS, and we discuss its efficacy in context of other available agents for DDLPS.

Analysis of clinical factors associated with survival in patients with soft-tissue sarcoma receiving trabectedin

OBJECTIVES

Soft-tissue sarcomas (STSs) are a heterogeneous group of rare malignancies. Treatment for advanced STS usually starts with anthracycline-based therapies, with no clear sequence for further treatment. A preferred option is trabectedin, especially for liposarcoma and leiomyosarcoma (L-sarcoma). However, due to severe side effects and few clinical trials, further research of the parameters affecting survival is necessary for the optimal selection of patients.

METHODS

We retrospectively analyzed 73 consecutive patients with STS treated with trabectedin at the University Hospital Centers at Zagreb and Osijek from 2014 to 2021. Our primary goals were evaluating factors affecting progression-free survival (PFS) and overall survival (OS).

RESULTS

The median PFS and OS for trabectedin were 3.6 months and 13.7 months, respectively. Patients with L-sarcoma exhibited longer PFS and a trend towards longer OS compared to those with non-L-sarcoma. However, these effects were primarily a result of the myxoid liposarcoma subtype, which exhibited a median PFS of 21.1 months and a median OS of 33.3 months, both significantly longer compared to non-myxoid L-sarcoma. Additionally, patients with three or more sites of metastases exhibited shorter median PFS (3.1 months vs. 3.6 months) and OS (5.7 months vs. 23.8 months) compared to only one metastatic site. There was no correlation between the PFS values of trabectedin and pazopanib and no difference in survival, regardless of the treatment sequence.

CONCLUSIONS

Trabectedin treatment yields the greatest survival benefit in patients with myxoid liposarcoma and low metastatic burden, whereas the additional use of pazopanib provides further clinical benefit, regardless of treatment sequence.

Non-gastrointestinal stromal tumours soft tissue sarcomas: an update

Soft tissue sarcomas (STS) encompass a diverse family of neoplasms of mesenchymal origin, marked by significant heterogeneity in terms of physiopathology, molecular characterisation, natural history and response to different therapies. This review aims to summarise the current strategies for the management of patients with STS, including surgery, systemic treatments and radiation therapy, along with considerations applicable to the most frequent subtypes, as well as particularities associated with less common and specific histologies. It also provides insights into upcoming strategies to tackle this challenging group of diseases.

Combination of PPARγ Agonist Pioglitazone and Trabectedin Induce Adipocyte Differentiation to Overcome Trabectedin Resistance in Myxoid Liposarcomas

PURPOSE

This study was aimed at investigating whether the PPARγ agonist pioglitazone-given in combination with trabectedin-is able to reactivate adipocytic differentiation in myxoid liposarcoma (MLS) patient-derived xenografts, overcoming resistance to trabectedin.

EXPERIMENTAL DESIGN

The antitumor and biological effects of trabectedin, pioglitazone, and the combination of the two drugs were investigated in nude mice bearing well-characterized MLS xenografts representative of innate or acquired resistance against trabectedin. Pioglitazone and trabectedin were given by daily oral and weekly i.v. administrations, respectively. Molecular studies were performed by using microarrays approach, real-time PCR, and Western blotting.

RESULTS

We found that the resistance of MLS against trabectedin is associated with the lack of activation of adipogenesis. The PPARγ agonist pioglitazone reactivated adipogenesis, assessed by histologic and gene pathway analyses. Pioglitazone was well tolerated and did not increase the toxicity of trabectedin. The ability of pioglitazone to reactivate adipocytic differentiation was observed by morphologic examination, and it is consistent with the increased expression of genes such as ADIPOQ implicated in the adipogenesis process. The determination of adiponectin by Western blotting constitutes a good and reliable biomarker related to MLS adipocytic differentiation.

CONCLUSIONS

The finding that the combination of pioglitazone and trabectedin induces terminal adipocytic differentiation of some MLSs with the complete pathologic response and cure of tumor-bearing mice provides a strong rationale to test the combination of trabectedin and pioglitazone in patients with MLS.

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

BACKGROUND

Myxoid 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.

METHODS

Through repeated in vivo treatment in athymic nude mice, we have obtained a patient-derived xenograft with acquired resistance to trabectedin.

RESULTS

At 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.

CONCLUSIONS

This 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.

Using biology to guide the treatment of sarcomas and aggressive connective-tissue tumours

Sarcomas are a heterogeneous group of malignancies that arise from cells of a mesenchymal origin. Surgery forms the mainstay of the treatment of most patients with localized sarcoma and might be followed or preceded by chemotherapy and/or radiotherapy. In the metastatic setting, systemic treatments tend to improve survival and control symptoms. However, the adverse events and sometimes disappointing outcomes associated with these empirical approaches to treatment indicate a need for new approaches. The advent of next-generation sequencing (NGS) has enabled more targeted treatment of many malignancies based on the presence of specific alterations. NGS analyses of sarcomas have revealed the presence of many alterations that can be targeted using therapies that are already used in patients with other forms of cancer. In this Review, we describe the genomic alterations considered to define specific nosological subgroups of sarcoma and whose contribution to oncogenesis provides a biological rationale for the use of a specific targeted therapy. We also report several less successful examples that should guide researchers and clinicians to better define the extent to which the identification of driver molecular alterations should influence the development of novel treatments.

Preserving quality of life as a key treatment goal in advanced soft tissue sarcomas

INTRODUCTION

Health-related quality of life (HRQoL) is a patient-reported outcome that addresses patients' perceptions of symptoms across physical, emotional, cognitive and social domains. As HRQoL is currently rarely measured outside clinical trials in oncology, it must be inferred from patients' everyday performance during treatment. To gain insight into the HRQoL of advanced STS patients receiving palliative treatment in clinical practice, three case studies of patients treated with trabectedin are examined. Areas covered: The patient in Case 1 has maintained complete remission for more than 8 years after receiving nine cycles of second-line trabectedin followed by secondary surgery for recurrent myxoid liposarcoma, and was able to resume normal activities during trabectedin treatment. Case 2 describes 10 years' follow-up of a patient with myxoid liposarcoma who remains well after many lines of chemotherapy including extended use of trabectedin in the second line. The third case illustrates the feasibility of extending survival time in an elderly patient with metastatic leiomyosarcoma who was able to maintain a busy and active lifestyle while receiving second-line trabectedin. Expert commentary: Owing to its relatively benign safety profile, trabectedin frequently permits prolonged therapy and is generally well tolerated, often allowing patients to carry on with normal daily activities.

More Than 50 Subtypes of Soft Tissue Sarcoma: Paving the Path for Histology-Driven Treatments

Sarcomas are a diverse group of cancers with mesenchymal origin. Although sarcomas comprise less than 1% of cancers, there are more than 50 different subtypes that are quite different from one another in terms of both their biology and clinical behavior. Historically, the need for adequate patient numbers in clinical trials has pushed sarcoma researchers to lump these very different malignancies together and treat the patients using a "one-size-fits-all" approach. However, with improvements in our scientific understanding, we are finally ready for a histology-tailored therapeutic approach to these complex diseases. In this review, we discuss key advances in our understanding of the biology underlying selected sarcoma subtypes and how targeting these subtypes is relevant therapeutically with respect to both molecularly targeted agents as well as immunotherapy.

High-Dose Ifosfamide Chemotherapy in a Series of Patients Affected by Myxoid Liposarcoma

Background

To report on the activity of high-dose prolonged-infusion ifosfamide (HDIFX) chemotherapy in a retrospective series of patients affected by myxoid liposarcoma treated at Fondazione IRCCS Istituto Nazionale dei Tumori in Milan, Italy.

Patients and Methods

Patients with an advanced myxoid liposarcoma treated with HDIFX (14 g/sqm, i.v., prolonged infusion of 14 days every 28 days) as a single agent between May 2002 and April 2017 were retrospectively reviewed. All pathologic diagnoses were centrally reviewed and molecularly confirmed. Response was evaluated by RECIST, and survival functions were computed by the Kaplan-Meier method.

Results

Eleven patients with advanced myxoid liposarcoma were treated with HDIFX (male/female = 9/2, median age 33 years, range 31–75). Among these, 1/11 received HDIFX in first line, 5/11 in second line, 3/11 in third line, and 2/11 in fourth line for a median course number of 3 (range 2–7). No RECIST objective responses were observed. Overall median progression-free survival was 1,9 months. Median overall survival was 37 months. At a median follow-up of 115 months, 1 patient is alive.

Conclusions

In this series of patients affected by advanced myxoid liposarcoma, chemotherapy with HDIFX was essentially inactive.

Treatment of advanced, metastatic soft tissue sarcoma: latest evidence and clinical considerations

Soft tissue sarcoma (STS) is a biologically heterogeneous malignancy with over 50 subtypes. Historically, there have been few systemic treatment options for this relatively rare disease. Traditional cytotoxic agents, such as anthracyclines, alkylating agents, and taxanes have limited clinical benefit beyond the first-line setting; across all high-grade STS subtypes, median overall survival remains approximately 12-18 months for advanced metastatic disease. The development of targeted therapies has led to recent US Food and Drug Administration approval of four new treatments for high-grade STS in the advanced metastatic setting. Among these, olaratumab is most notable for its improvement in overall survival for patients with anthracycline-naïve disease. Further progress in STS management will rely on novel trial design, subtype-specific therapies and validation of biomarkers to tailor therapy. Immunotherapy has shown promise as a new, but yet undiscovered frontier in the management of STS.

High-Throughput Screening of Myxoid Liposarcoma Cell Lines: Survivin Is Essential for Tumor Growth

Myxoid liposarcoma (MLS) is a soft tissue sarcoma characterized by a recurrent t(12;16) translocation. Although tumors are initially radio- and chemosensitive, the management of inoperable or metastatic MLS can be challenging. Therefore, our aim was to identify novel targets for systemic therapy. We performed an in vitro high-throughput drug screen using three MLS cell lines (402091, 1765092, DL-221), which were treated with 273 different drugs at four different concentrations. Cell lines and tissue microarrays were used for validation. As expected, all cell lines revealed a strong growth inhibition to conventional chemotherapeutic agents, such as anthracyclines and taxanes. A good response was observed to compounds interfering with Src and the mTOR pathway, which are known to be affected in these tumors. Moreover, BIRC5 was important for MLS survival because a strong inhibitory effect was seen at low concentration using the survivin inhibitor YM155, and siRNA for BIRC5 decreased cell viability. Immunohistochemistry revealed abundant expression of survivin restricted to the nucleus in all 32 tested primary tumor specimens. Inhibition of survivin in 402-91 and 1765-92 by YM155 increased the percentage S-phase but did not induce apoptosis, which warrants further investigation before application in the treatment of metastatic MLS. Thus, using a 273-compound drug screen, we confirmed previously identified targets (mTOR, Src) in MLS and demonstrate survivin as essential for MLS survival.

The importance of treating by histological subtype in advanced soft tissue sarcoma

While surgical resection (±radiotherapy) is standard treatment for localized soft tissue sarcomas (STS), chemotherapy is the mainstay for managing locally advanced and metastatic disease. Expanding knowledge of the biologies and sensitivities of STS histotypes, in conjunction with results from a growing collection of retrospective reviews and prospective randomized studies, point to the importance of treating in consideration of histological subtype. Doxorubicin ± ifosfamide continues to be standard first-line therapy for most STS subtypes. Main options for second- or later-line therapy include trabectedin, dacarbazine, gemcitabine combinations, pazopanib and, most recently, eribulin. Using illustrative case studies, treatment options are reviewed for three of the more common STS subtypes - uterine leiomyosarcoma, liposarcoma and synovial sarcoma - with a focus on use of trabectedin.

Pharmacological therapies for Liposarcoma

INTRODUCTION

Liposarcoma (LS) is one of the most common adult soft tissue sarcomas (STS). For metastatic disease, systemic treatment options were historically represented by standard cytotoxic chemotherapy. More recently, innovative therapies have been introduced and they are currently part of the therapeutic armamentarium, positively impacting disease control and patients' quality of life. Moreover, in the last decade, a better understanding of the molecular characteristics of each STS subtype allowed to detect new potential targets and develop novel, biology-driven compounds at different stages of testing. Areas covered: This review is focused on LS, retracing their pharmacological management, starting with a summary of results achieved with standard chemotherapy, then moving to a deeper analysis on data obtained with new, approved therapies and finally reporting an update on ongoing clinical trials, thus providing an overview on the current scenario and outlining how it might evolve in the coming years. Expert commentary: Important strides have been made in the knowledge and treatment of LS. Peculiar molecular features and fundamental signalling pathways represent nowadays druggable targets for novel therapies. However, predictive biomarkers still need to be identified in order to better select the target population, to possibly test combinations of drugs, with the ultimate goal of improving outcomes.

Systemic Therapy for Advanced Soft Tissue Sarcoma

Soft tissue sarcomas are rare tumors that present with distant metastasis in up to 10% of patients. Survival has improved significantly because of advancements in histologic classification and improved management approaches. Older agents such as doxorubicin, ifosfamide, gemcitabine, and paclitaxel continue to demonstrate objective response rates from 18% to 25%. Newer agents such as trabectedin, eribulin, aldoxorubicin, and olaratumab have demonstrated improvements in progression-free survival, overall survival, or toxicity profiles. Future studies on treatment of advanced soft tissue sarcoma will continue to concentrate on reducing toxicity, personalization of therapy, and targeting novel pathways.

Current classification, treatment options, and new perspectives in the management of adipocytic sarcomas

Sarcomas are a heterogeneous group of mesenchymal tumors arising from soft tissue or bone, with an uncertain etiology and difficult classification. Soft tissue sarcomas (STSs) account for around 1% of all adult cancers. Till date, more than 50 histologic subtypes have been identified. Adipocyte sarcoma or liposarcoma (LPS) is one of the most common STS subtypes, accounting for 15% of all sarcomas, with an incidence of 24% of all extremity STSs and 45% of all retroperitoneal STSs. The new World Health Organization classification system has divided LPS into four different subgroups: atypical lipomatous tumor/well-differentiated LPS, dedifferentiated LPS, myxoid LPS, and pleomorphic LPS. These lesions can develop at any location and exhibit different aggressive potentials reflecting their morphologic diversity and clinical behavior. Patients affected by LPS should be managed in specialized multidisciplinary cancer centers. Whereas surgical resection is the mainstay of treatment for localized disease, the benefits of adjuvant and neoadjuvant chemotherapy are still unclear. Systemic treatment, particularly chemotherapy, is still limited in metastatic disease. Despite the efforts toward a better understanding of the biology of LPS, the outcome of advanced and metastatic patients remains poor. The advent of targeted therapies may lead to an improvement of treatment options and clinical outcomes. A larger patient enrollment into translational and clinical studies will help increase the knowledge of the biological behavior of LPSs, test new drugs, and introduce new methodological studies, that is, on treatment response.

Recent advances in targeted therapy for Ewing sarcoma

Ewing sarcoma is an aggressive, poorly differentiated neoplasm of solid bone that disproportionally afflicts the young. Despite intensive multi-modal therapy and valiant efforts, 70% of patients with relapsed and metastatic Ewing sarcoma will succumb to their disease. The persistent failure to improve overall survival for this subset of patients highlights the urgent need for rapid translation of novel therapeutic strategies. As Ewing sarcoma is associated with a paucity of mutations in readily targetable signal transduction pathways, targeting the key genetic aberration and master regulator of Ewing sarcoma, the EWS/ETS fusion, remains an important goal.

Long-term response to first-line trabectedin in an elderly female patient with a metastatic leiomyosarcoma unfit for anthracycline

Systemic chemotherapy comprising anthracycline monotherapy is the standard regimen for metastatic soft tissue sarcomas, particularly leiomyosarcomas, which have limited sensitivity to ifosfamide. However, the optimal chemotherapy regimen for elderly patients, especially those considered unfit for anthracyclines, is undefined. Trabectedin is a potent marine-derived antineoplastic drug with documented activity in liposarcomas and leiomyosarcomas. It is registered in Europe for the treatment of adult patients with advanced soft tissue sarcoma, after failure of anthracyclines and ifosfamide, or who are unsuited to receive these agents. We report the long-term response to first-line trabectedin therapy in an elderly patient with metastatic leiomyosarcoma unfit for standard therapy. A 66-year-old woman underwent resection of a pelvic epithelioid leiomyosarcoma with positive margins in December 2002, followed by postoperative radiotherapy. In February 2012, she was diagnosed with multiple lung lesions and local relapse in the pelvis. As she was considered unsuitable for both anthracycline and ifosfamide because of cardiovascular comorbidities and because she was highly anxious at the prospect of developing alopecia, vomiting, and fatigue, we commenced treatment with trabectedin at 75% of the standard dose of 1.5 mg/m² every 3 weeks. Treatment was well tolerated, and the patient continued treatment for 25 cycles, with disease stabilization according to the RECIST criteria and a partial response according to the Choi criteria. Disease progression was observed in November 2013 and the patient died 20 months after the diagnosis of metastases. Trabectedin may represent an alternative option for highly selected elderly patients with metastatic sarcoma and unfit for anthracyclines; careful monitoring of toxicities is strongly recommended.

HPLC-MS/MS method to measure trabectedin in tumors: preliminary PK study in a mesothelioma xenograft model

BACKGROUND

Trabectedin is an anticancer agent registered for the second-line treatment of soft tissue sarcoma and ovarian cancer. No preclinical data are available on its tumor distribution, so a method for quantification in neoplastic tissues is required.

METHODS/RESULTS

We validated an LC-MS/MS assay determining the recovery, sensitivity, linearity, precision and accuracy in mouse tumor and liver samples. The limit of quantification was 0.10 ng/ml with a curve range of 0.10-3.00 ng/ml (accuracy 96.1-102.1%). Inter-day precision and accuracy of QCs were 6.0-8.2 and 97.0-102.6% respectively. The method was applied in mesothelioma xenografts treated with therapeutic doses.

CONCLUSION

The method was validated for measuring trabectedin in tissues. In a mesothelioma xenograft model, trabectedin distributed preferentially in tumor compared with liver.

Efficacy of trabectedin in advanced soft tissue sarcoma: beyond lipo- and leiomyosarcoma

Objective

Trabectedin is effective in leiomyosarcoma and liposarcoma, especially the myxoid variant, related to the presence of the FUS-CHOP transcript. We evaluated the efficacy of trabectedin in specific subgroups of patients with soft tissue sarcomas (STS).

Methods

Seventy-two patients with advanced anthracycline-pretreated STS, who received trabectedin at a dose of 1.5 mg/m² every 3 weeks by continuous 24-hour infusion, were retrospectively analyzed. Best response rate according to Response Evaluation Criteria In Solid Tumors (RECIST) criteria and severe adverse events (AEs) according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE v4.02) were evaluated. Secondary endpoints included progression-free survival and overall survival (OS).

Results

Median age was 48 (range, 20–75) years, with a median Eastern Cooperative Oncology Group performance status of 0. The median number of previous chemotherapy regimens was 1 (range, 0–5). Median number of trabectedin cycles was 3 (range, 1–17). About 69/72 patients (95.8%) were evaluable for response: 9 patients (13%) achieved partial response and 26 (37.7%) stable disease. According to histotype, clinical benefit (partial response + stable disease) was reported in synovial sarcoma (n=5), retroperitoneal liposarcoma (n=10), myxoid liposarcoma (n=5), leiomyosarcoma (n=8), high-grade undifferentiated pleomorphic sarcoma (n=5), Ewing/peripheral primitive neuroectodermal tumor (n=1), and malignant peripheral nerve sheath tumor (n=1). Any grade AEs were noncumulative, reversible, and manageable. G3/G4 AEs included anemia (n=1, 1.4%), neutropenia (n=7, 9.6%), liver toxicity (n=6, 8.3%), and fatigue (n=2, 2.8%). With a median follow-up time of 11 (range, 2–23) months, median progression-free survival and OS of the entire cohort were 2.97 months and 16.5 months, respectively.

Conclusion

Our experience confirms trabectedin as an effective therapeutic option for metastatic lipo- and leiomyosarcoma and suggests promise in synovial sarcomas and high-grade undifferentiated pleomorphic 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.

Advances in the targeted therapy of liposarcoma

Liposarcoma (LPS) is the most common type of soft-tissue sarcoma. Complete surgical resection is the only curative means for localized disease; however, both radiation and conventional cytotoxic chemotherapy remain controversial for metastatic or unresectable disease. An increasing number of trials with novel targeted therapy of LPS have provided encouraging data during recent years. This review will provide an overview of the advances in our understanding of LPS and summarize the results of recent trials with novel therapies targeting different genetic and molecular aberrations for different subtypes of LPS.

Liposarcoma: a soft tissue tumor with many presentations

Liposarcoma is an uncommon connective tissue tumor arising from lipoblast cells. The lesion is located in body soft parts and rarely arises from the bones. The tumors are variable in presentation ranging from benign well-differentiated tumors to myxoid and round cell-dedifferentiated and pleomorphic forms which can present with metastases. The lesions are most often treated by surgical resection. Chemotherapy and radiation may be added to the treatment of the more malignant variants with some success.

Trabectedin for desmoplastic small round cell tumours: a possible treatment option?

BACKGROUND

Desmoplastic small round cell tumour (DSRCT) is a rare sarcoma typically affecting young males and usually widely metastatic at presentation. Despite multimodal treatment approaches, the prognosis for DSRCT is extremely poor. Alkylator- and anthracyclines- based regimens are widely used as therapy and an initial response is common. Durable responses are exceptionally rare so further systemic treatment options for these patients represent an unmet medical need. We report two cases of metastatic, pretreated DSRCT patients achieving disease stabilisation with Trabectedin.

METHODS

Retrospective review of 2 patients with progressive DSRCT, treated with Trabectedin.

RESULTS

Two males aged 19 and 23 years treated with Trabectedin, 1.5 mg/m(2) over 24 hours 3 weekly for 6 and 5 cycles respectively. Best responses were stable disease in patient 1 and partial response (RECIST 1.1) in patient 2. Progression free survival was 4 months in both cases. Persistent neutropenia required 4 weekly administration in one patient but no other grade 3-4 toxicities occurred.

CONCLUSIONS

This report supports Trabectedin to be active and safe in pre-treated DSRCT patients. Further prospective and collaborative efforts are desirable to better define its role in the management of this disease.

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.

Tumor calcification: a new response pattern of myxoid liposarcoma to trabectedin

Introduction

Myxoid/round-cell liposarcoma (MRCL) is a specific histological subtype that accounts for 30–35% of liposarcomas and whose virulence depends on the quantity of round-cells within the tumor. MRCL is associated with specific chromosomal translocations resulting in the formation of CHOP/FUS and CHOP/EWS fusion proteins. A high sensitivity of MRCL to trabectedin was reported.

Case Report

We report the case of a 63-year-old woman with a bulky and metastatic MRCL, treated with trabectedin 1.5 mg/m² as a first-line treatment. She experienced a long-lasting clinical benefit. The patients received 14 cycles of trabectedin and achieved a durable partial response to the metastases and a stable disease of the primary tumor, which is a very favorable safety profile. Also noteworthy is that we have observed a calcification of the primary tumor and the metastasis. The response, which lasted 30 months, led to a symptomatic improvement, associated with an excellent general condition and an absence of pain.

Conclusion

To the best of our knowledge, this is the first report of a MRCL treated with trabectedin that resulted in a calcification of the primary tumor and the metastases, associated with an outstandingly long response. This case suggests that trabectedin may represent a feasible first-line therapeutic option for patients with MRCL, with meaningful clinical benefits and an acceptable safety profile.

Adjuvant therapy for high-risk soft tissue sarcoma in the adult

OPINION STATEMENT

Adult-type soft tissue sarcomas (STS) are curable in roughly one half of cases. Surgery is the treatment mainstay in patients with localized STS and should be performed in centers that have specific expertise with the disease. Radiation therapy complements surgery in several cases, improving the local control. The value of adjuvant chemotherapy is still debated. There is some evidence, however, backing the notion that adjuvant chemotherapy may add to the systemic control of the disease, and thereby overall survival, in the subgroup of patients with high-risk STS. These patients are those with a high-grade, large, and deep tumor. Unfortunately, benefit is apparent when merging all data generated by several trials performed throughout decades, but it was not confirmed by the largest trials, including one that was recently reported. A confounding factor for large clinical trials is that STS are a family of 50-plus different histological subtypes. It is difficult to perform studies that focus on each of them separately, and subgroup analyses suffer from many limitations. Indeed, some histological types are more sensitive to standard chemotherapy and other are less. Furthermore, some histologies are specifically sensitive to some agents that may be completely inactive in others. A prospective, randomized trial is underway to compare standard neoadjuvant chemotherapy in high-risk STS versus a neoadjuvant regimen that is tailored to different histologies. Some rare histological subtypes (alveolar soft part sarcoma, clear cell sarcoma, extraskeletal myxoid chondrosarcoma, solitary fibrous tumor) have shown promising sensitivity to molecular target agents in the metastatic setting, but the value of these therapies in the adjuvant one has not been studied yet. It is probable that in the future the biological background of the different soft tissue sarcoma subtypes will guide the selection of therapies as well as the setting to deliver them.

Resistance to minor groove binders

In this paper multiple resistance mechanisms to minor groove binders (MGBs) are overviewed. MGBs with antitumor properties are natural products or their derivatives and, as expected, they are all substrates of P-glycoprotein (P-gp). However, a moderate expression of P-gp does not appear to reduce the sensitivity to trabectedin, the only MGB so far approved for clinical use. Resistance to this drug is often related to transcriptional mechanisms and to DNA repair pathways, particularly defects in transcription-coupled nucleotide excision repair (TC-NER). Therefore tumors resistant to trabectedin may become hypersensitive to UV rays and other DNA damaging agents acting in the major groove, such as Platinum (Pt) complexes. If this is confirmed in clinic, that will provide the rationale to combine trabectedin sequentially with Pt derivates.

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.

Mode of action of trabectedin in myxoid liposarcomas

To elucidate the mechanisms behind the high sensitivity of myxoid/round cell liposarcoma (MRCL) to trabectedin and the suggested selectivity for specific subtypes, we have developed and characterized three MRCL xenografts, namely ML017, ML015 and ML004 differing for the break point of the fusion gene FUS-CHOP, respectively of type I, II and III. FUS-CHOP binding to the promoters of some target genes such as Pentraxin 3 or Fibronectin 1, assessed by chromatin immunoprecipitation, was strongly reduced in the tumor 24 h after the first or the third weekly dose of trabectedin, indicating that the drug at therapeutic doses causes a detachment of the FUS-CHOP chimera from its target promoters as previously shown in vitro. Moreover, the higher sensitivity of MRCL types I and II appears to be related to a more prolonged block of the transactivating activity of the fusion protein. Doxorubicin did not affect the binding of FUS-CHOP to target promoters. Histologically, the response to trabectedin in ML017 and ML015 was associated with a marked depletion of non-lipogenic tumoral cells and vascular component, as well as lipidic maturation as confirmed by PPARγ2 expression in western Blot. By contrast, in ML004 no major changes either in the cellularity or in the amount of mature were found, and consistently PPARγ2 was null. In conclusion, the data support the view that the selective mechanism of action of trabectedin in MRCL is specific and related to its ability to cause a functional inactivation of the oncogenic chimera with consequent derepression of the adypocytic differentiation.