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Importance Three years of adjuvant imatinib mesylate therapy is associated with reduced recurrence rates and improved overall survival in patients with high-risk primary gastrointestinal stromal tumor (GIST) compared with patients who receive 1 year of treatment. The impact of a longer duration of therapy is unknown. Objective To determine whether adjuvant treatment for primary GIST with imatinib for 5 years is tolerable and efficacious. Design, Setting, and Participants This prospective, single-arm, phase 2 clinical trial (Postresection Evaluation of Recurrence-free Survival for Gastrointestinal Stromal Tumors With 5 Years of Adjuvant Imatinib [PERSIST-5]) included adult patients with primary GIST (expressing KIT) at 21 US institutions who underwent a macroscopically complete resection and were at intermediate or high risk of recurrence, defined as primary GIST at any site measuring 2 cm or larger with 5 or more mitoses per 50 high-power field or nongastric primary GIST measuring 5 cm or larger. Data were collected from August 5, 2009, through December 20, 2016. Interventions Imatinib, 400 mg once daily, orally for 5 years or until discontinuation of therapy because of progression or intolerance. Main Outcomes and Measures The primary end point was recurrence-free survival (RFS). The secondary end point was overall survival. Results Of the 91 patients enrolled, 48 (53%) were men with a median age of 60 years (range, 30-90 years). Median tumor size was 6.5 cm (range, 2.3-30.0 cm). Median treatment duration was 55.1 months (range, 0.5-60.6 months); 46 patients (51%) completed 5 years of imatinib therapy. Estimated 5-year RFS was 90% (95% CI, 80%-95%), and overall survival was 95% (95% CI, 86%-99%). Recurrence was noted in 7 patients: 1 had disease recur while receiving imatinib (PDGFRAD842V mutation) and died; 6 had disease recur after discontinuation of imatinib therapy. Two additional deaths were unrelated to treatment or tumor progression. Forty-five patients (49%) stopped treatment early because of patient choice (10 [21%]), adverse events (15 [16%]), or other (11 [12%]). All 91 patients experienced at least 1 adverse event, and 17 (19%) experienced grade 3 or 4 adverse events. Conclusions and Relevance In this first adjuvant trial, to our knowledge, of patients with resected primary GIST who received 5 years of imatinib therapy, no patient with imatinib-sensitive mutations had disease recur during therapy. For patients in whom disease recurred, recurrence was within 2 years of discontinuation of imatinib therapy. Approximately half of the patients discontinued treatment early, most commonly because of patient choice, thus emphasizing the importance of close clinical monitoring to continue imatinib treatment for patients at appropriate risk. Trial Registration ClinicalTrials.gov identifier:NCT00867113

Background Ontuxizumab, a humanized monoclonal antibody, targets endosialin (tumor endothelial marker 1 [TEM‐1] or CD248), which is expressed on sarcoma cells and is believed to be involved in tumor angiogenesis. This is the first trial to evaluate ontuxizumab in patients with sarcoma. Methods Part 1 was an open‐label, dose‐finding, safety lead‐in: 4, 6, or 8 mg/kg with gemcitabine and docetaxel (G/D; 900 mg/m2 gemcitabine on days 1 and 8 and 75 mg/m2 docetaxel on day 8). In part 2, patients were randomized in a double‐blind fashion in 2:1 ratio to ontuxizumab (8 mg/kg) or a placebo with G/D. Randomization was stratified by 4 histological cohorts. Results In part 2 with 209 patients, no significant difference in progression‐free survival between ontuxizumab plus G/D (4.3 months; 95% confidence interval [CI], 2.7‐6.3 months) and the placebo plus G/D (5.6 months; 95% CI, 2.6‐8.3 months) was observed (P = .67; hazard ratio [HR], 1.07; 95% CI, 0.77‐1.49). Similarly, there was no significant difference in median overall survival between the 2 groups: 18.3 months for the ontuxizumab plus G/D group (95% CI, 16.2‐21.1 months) and 21.1 months for the placebo plus G/D group (95% CI, 14.2 months to not reached; P = .32; HR, 1.23; 95% CI, 0.82‐1.82). No significant differences between the treatment groups occurred for any efficacy parameter by sarcoma cohort. The combination of ontuxizumab plus G/D was generally well tolerated. Conclusions Ontuxizumab plus G/D showed no enhanced activity over chemotherapy alone in soft‐tissue sarcomas, whereas the safety profile of the combination was consistent with G/D alone., Endosialin is involved in tumor blood vessel formation and is expressed on sarcoma tumor cells. This phase 1/2 randomized controlled trial shows that ontuxizumab, an endosialin‐directed monoclonal antibody, does not enhance efficacy in sarcomas when it is combined with chemotherapy (gemcitabine and docetaxel), although the combination is generally well tolerated.

Importance Alveolar soft-part sarcoma (ASPS) is a rare, translocation-driven sarcoma of the soft tissues. Alveolar soft-part sarcoma often affects young adults and is characterized by indolent behavior but early evidence of metastatic spread. After recognition of ASPS as a specific entity in 1952, retrospective data indicated prolonged survival in patients with metastases, despite inherent resistance to conventional doxorubicin-based chemotherapy. Tyrosine kinase inhibitors and immune checkpoint inhibitors have provided unexpected new treatment strategies for ASPS. Observations This review includes articles published between 1952 and March 1, 2018. With the introduction of new molecular diagnostic tools and therapies, the distinctive features of ASPS have become more evident. The identification and better understanding of molecular pathways activated by the characteristic t(X;17)(p11;q25) translocation and its correspondent chimeric ASPSCR1-transcription factor E3 (TFE3) fusion protein open new paths to drug development. The associations of TFE3 and facilitation of an immunosuppressive microenvironment provide a rationale for exploring treatments that affect the balance between T-effector cells and T-regulatory cells. Tyrosine kinase inhibitors, such as sunitinib, cediranib, and pazopanib, show activity with either tumor responses or disease stabilization in more than 50% of the cases. Given the association of new agents with patient outcomes, it is too early to say whether metastatic ASPS should still be considered incurable in all patients. Conclusions and Relevance The biologic outcomes of the canonical genomic event in ASPS remain under investigation; a better understanding of the tumor microenvironment and the multiple pathways activated in this sarcoma, including unusual bioenergetics, MET signaling, and angiogenesis, should lead to more rational therapy. Basket trials and related prospective studies focusing on the intersection of specific signaling pathways and diseases with unique genomic features, such as ASPS, will provide an understanding of new options for care.

BACKGROUND. Sorafenib and dacarbazine have low single‐agent response rates in metastatic sarcomas. As angiogenesis inhibitors can enhance the efficacy of chemotherapy, we investigated the combination of sorafenib and dacarbazine in select sarcoma subtypes. MATERIALS AND METHODS. Patients with leiomyosarcoma (LMS), synovial sarcoma (SS), or malignant peripheral nerve sheath tumors (MPNST) with up to two previous lines of therapy and adequate hepatic, renal, and marrow function received 3‐week cycles of sorafenib at 400 mg oral twice daily and dacarbazine 1,000 mg/m(2) intravenously (later reduced to 850 mg/m(2)). Patients were evaluated for response every 6 weeks. The primary objective was to determine the disease control rate (DCR) of sorafenib plus dacarbazine in the selected sarcoma subtypes. RESULTS. The study included 37 patients (19 female); median age was 55 years (range 26–87); and histologies included LMS (22), SS (11), and MPNST (4). The DCR was 46% (17/37). Median progression‐free survival was 13.4 weeks. The RECIST response rate was 14% (5/37). The Choi response rate was 51% (19/37). Median overall survival was 13.2 months. Of the first 25 patients, 15 (60%) required dacarbazine dose reductions for hematologic toxicity, with one episode of grade 5 neutropenic fever. After reducing the starting dose of dacarbazine to 850 mg/m(2), only 3 of the final 12 (25%) patients required dose reduction. CONCLUSION. This phase II study met its primary endpoint with an 18‐week DCR of 46%. The clinical activity of dacarbazine plus sorafenib in patients with these diagnoses is modest. IMPLICATIONS FOR PRACTICE. Metastatic soft tissue sarcomas are a heterogeneous group of relatively rare malignancies. Most patients are treated with cytotoxic chemotherapy or targeted therapy in the form of tyrosine kinase inhibitors. Response rates are relatively low, and there is a need for better therapies. This clinical trial demonstrates that combining a cytotoxic therapy (dacarbazine) with an antiangiogenic small molecule (sorafenib) is feasible and associated with favorable disease‐control rates; however, it also increases the potential for significant toxicity.

AIMS: TERT promoter mutations have been reported in 22% of solitary fibrous tumors (SFT) and have been associated with poor outcomes. We performed testing for TERT hotspot mutations in a large series of solitary fibrous tumors in order to confirm this finding and explore clinicopathologic correlates of mutation status. METHODS AND RESULTS: PCR for TERT hotspot mutations C250T and C228T was performed on DNA extracted from 216 SFT, and mutation status correlated with clinicopathological factors including predicted risk for metastasis using a previously published model. Testing was successful in 189 tumors from 172 patients, and mutations were present in 29%. Presence of TERT promoter mutation was associated with larger primary tumor size, necrosis and older patient age. TERT promoter mutations were most common in high risk tumors (9/20, 45%), and were present in 11/26 (42%) moderate risk tumors, and 14/67 (21%) low risk tumors (p=0.004). Overall, TERT mutations were associated with shorter time to first metastasis (p=0.04), but had no impact on overall survival. TERT promoter mutation status was found not to provide additional prognostic information in low and high risk SFT, but did identify a group of patients with intermediate risk SFT who had an increased risk of metastasis. CONCLUSIONS: TERT promoter mutations were more frequent in SFT with higher risk of metastasis, but TERT promoter mutation status was not a reliable predictor of clinical outcome by itself. However, mutations in the TERT promoter may be useful in further stratifying patients with intermediate risk tumors. This article is protected by copyright. All rights reserved.

INTRODUCTION: Retroperitoneal sarcoma (RPS) is a rare disease accounting for 0.1%–0.2% of all malignancies. Management of RPS is complex and requires multidisciplinary, tailored treatment strategies at all stages, but especially in the context of metastatic or multifocal recurrent disease. Due to the rarity and heterogeneity of this family of diseases, the literature to guide management is limited. METHODS: The Trans-Atlantic Retroperitoneal Sarcoma Working Group (TARPSWG) is an international collaboration of sarcoma experts from all disciplines convened in an effort to overcome these limitations. The TARPSWG has compiled the available evidence surrounding metastatic and multifocally recurrent RPS along with expert opinion in an iterative process to generate a consensus document regarding the complex management of this disease. The objective of this document is to guide sarcoma specialists from all disciplines in the diagnosis and treatment of multifocal recurrent or metastatic RPS. RESULTS: All aspects of patient assessment, diagnostic processes, local and systemic treatments, and palliation are reviewed in this document, and consensus recommendations provided accordingly. Recommendations were guided by available evidence, in conjunction with expert opinion where evidence was lacking. CONCLUSIONS: This consensus document combines the available literature regarding the management of multifocally recurrent or metastastic RPS with the practical expertise of high-volume sarcoma centers from multiple countries. It is designed as a tool for decision making in the complex multidisciplinary management of this condition and is expected to standardize management across centers, thereby ensuring that patients receive the highest quality care.

BACKGROUND: Desmoid tumors (also referred to as aggressive fibromatosis) are connective tissue neoplasms that can arise in any anatomical location and infiltrate the mesentery, neurovascular structures, and visceral organs. There is no standard of care. METHODS: In this double-blind, phase 3 trial, we randomly assigned 87 patients with progressive, symptomatic, or recurrent desmoid tumors to receive either sorafenib (400-mg tablet once daily) or matching placebo. Crossover to the sorafenib group was permitted for patients in the placebo group who had disease progression. The primary end point was investigator-assessed progression-free survival; rates of objective response and adverse events were also evaluated. RESULTS: With a median follow-up of 27.2 months, the 2-year progression-free survival rate was 81% (95% confidence interval [CI], 69 to 96) in the sorafenib group and 36% (95% CI, 22 to 57) in the placebo group (hazard ratio for progression or death, 0.13; 95% CI, 0.05 to 0.31; P

BACKGROUND: Patients with gastrointestinal stromal tumour (GIST) are often followed up after surgery with longitudinally repeated imaging examinations to detect recurrence early. Studies on follow-up of GIST patients are few, the optimal follow-up methods are unknown and the recommendations for follow-up vary in guidelines. METHODS: We reviewed the current evidence for follow-up of patients treated with surgery alone and of patients who were treated with adjuvant or neoadjuvant imatinib. RESULTS: Imaging of the abdomen and the pelvis with computerised tomography (CT) or magnetic resonance imaging (MRI) usually suffices, since metastases are uncommon at other sites. The frequency of imaging may be adjusted with the risk of recurrence with time. Very low risk GISTs are very frequently cured with surgery and usually require no regular follow-up after complete surgery, and annual CT of the abdomen and the pelvis for 5 years suffices for most patients with a low to intermediate risk for recurrence. Most high-risk patients are treated with imatinib for at least 3 years after surgery. CT or MRI may be carried out 6-monthly during adjuvant imatinib, 3 to 4-monthly during the 2 years that follow discontinuation of imatinib when the risk of recurrence is high, and then at 6-12 month intervals to complete 10 years of follow-up. Recurrence after the first 10 years of follow-up is infrequent. CONCLUSIONS: The follow-up schedules are best tailored with the risk of recurrence. The risk of recurrence should be estimated with the prognostic tools that consider the most relevant prognostic factors. ispartof: European Journal of Cancer vol:51 issue:12 pages:1611-1617 ispartof: location:England status: published

After the revelation of kinase targeting with orally available small molecules, the use of imatinib in chronic myelogenous leukemia and in gastrointestinal stromal tumor (GIST) has now become commonplace and just two of many examples of the use of kinase inhibitors in cancer. In this article, we discuss important practice points that may impact upon questions of therapy of primary and metastatic GIST, with the hope that the questions addressed in this rare solid tumor can serve as examples of what can be achieved with kinase-directed therapies in other cancers. We present cases that highlight some of the key issues in GIST management and afterward discuss both points of consensus and controversial issues in what is now recognized as one of the most common forms of sarcoma. Implications for Practice: The treatment of gastrointestinal stromal tumor (GIST) has become sophisticated with the availability of three approved agents in many countries and 15 years of experience with primary and metastatic disease. Important lessons from tyrosine-kinase inhibitors in GIST can be gleaned from this experience and will impact implementation of similar agents for other cancers.

Background. Estimates of unexpected uterine sarcoma following surgery for presumed benign leiomyoma that use age-stratification are lacking. Patients and Methods. A retrospective cohort of 2,075 patients that had undergone myomectomy was evaluated to determine the case incidence of unexpected uterine sarcoma. An aggregate risk estimate was generated using a meta-analysis of similar studies plus our data. Database-derived age distributions of the incidence rates of uterine sarcoma and uterine leiomyoma surgery were used to stratify risk by age. Results. Of 2,075 patients in our retrospective cohort, 6 were diagnosed with uterine sarcoma. Our meta-analysis revealed 8 studies from 1980 to 2014. Combined with our study, 18 cases of leiomyosarcoma are reported in 10,120 patients, for an aggregate risk of 1.78 per 1,000 (95% confidence interval [CI]: 1.1–2.8) or 1 in 562. Eight cases of other uterine sarcomas were reported in 6,889 patients, for an aggregate risk of 1.16 per 1,000 (95% CI: 0.5–4.9) or 1 in 861. The summation of these risks gives an overall risk of uterine sarcoma of 2.94 per 1,000 (95% CI: 1.8–4.1) or 1 in 340. After stratification by age, we predict the risk of uterine sarcoma to range from a peak of 10.1 cases per 1,000, or 1 in 98, for patients aged 75–79 years to Conclusion. The risk of unexpected uterine sarcoma varies significantly across age groups. Our age-stratified predictive model should be incorporated to more accurately counsel patients and to assist in providing guidelines for the surgical technique for leiomyoma.

Purpose: Metastatic gastrointestinal stromal tumour (GIST) is generally an incurable disease with variable response to imatinib. We aimed to develop prognostic nomograms to predict overall survival (OS) and progression-free survival (PFS) for patients treated with imatinib. Methods: Nomograms were developed in a training cohort (n = 330) of patients treated in a randomised trial (EORTC-ISG-AGITG 62005 phase III study) using Cox regression models, and validated in patients (n = 236) treated in routine clinical care from six referral centres. Nomogram performance was assessed by calculating the c statistic. A classification based on the nomograms' scores was generated to group patients according to risk. Results: Nomogram risk factors for OS and PFS were size of the largest metastasis, tumour genotype, primary tumour mitotic count, haemoglobin and blood neutrophil count at commencement of imatinib. The nomograms predicted survival with a c statistic of 0.75 (training) and 0.62 (validation) for OS, and 0.69 (training) and 0.62 (validation) for PFS. When tested in the validation cohort, the nomograms discriminated well the high and intermediate risk from low risk patients (hazard ratio [HR] for OS 3.83, 95% confidence interval [CI] 1.71-8.56; and 2.48, 95% CI 1.12-5.50; for PFS 2.84, 95% CI 1.66-4.87; and 1.45, 95% CI 0.87-2.41, respectively). Conclusion: The nomograms predicted the risk of GIST progression and death with good discrimination of risk groups, and may be of value for patient counselling and risk stratification. (C) 2015 Elsevier Ltd. All rights reserved.

Angiosarcoma, epithelioid hemangioendothelioma, and Kaposi sarcoma are classified according to the line of differentiation that these neoplastic cells most closely resemble: the endothelial cell. Although these malignant vascular sarcomas demonstrate immunohistochemical and ultrastructural features typical of this lineage, they vary dramatically in presentation and behavior, reflecting oncologic mechanisms unique to each. Antineoplastic therapies offer significant benefit, but because of the rarity of these cancers, novel therapies are slow to develop, and treatment options for these cancers remain limited. Antiangiogenic approaches that have shown benefit in other malignancies have not fully realized their promise in vascular tumors, suggesting that these tumors do not depend entirely on either angiogenic growth factors or on neighboring endothelia that are affected by these agents. Nonetheless, translational studies have begun to unravel these distinct pathologies, identifying novel translocation products, targets of oncogenic virulence factors, and genomic mutations that hijack angiogenic signaling and drive malignant growth. Concurrently, an elaborate and highly regulated model of angiogenesis and lymphangiogenesis involving vascular endothelial growth factor–receptor tyrosine kinase and TGF-β and Notch pathways has emerged that informs treatment of these tumors as well as cancer in general. This review summarizes the literature on malignant vascular sarcomas in the context of current models of angiogenesis and, in light of recent clinical trial data, could help clinician-scientists generate novel therapeutic approaches.

Background Alveolar soft part sarcoma (ASPS) is an exceedingly rare and orphan disease, without active drugs approved in the front line. Pazopanib and trabectedin are licensed for sarcoma treatment from second-line, but very little and contradictory data are available on their activity in ASPS. Lacking ongoing and/or planned clinical trials, we conducted a multi-institutional study involving the reference sites for sarcoma in Europe, U.S., and Japan, within the World Sarcoma Network, to investigate the efficacy of pazopanib and trabectedin. Materials and Methods From May 2007, 14 of the 27 centers that were asked to retrospectively review their databases had identified 44 advanced ASPS patients treated with pazopanib and/or trabectedin. Response was evaluated by Response Evaluation Criteria in Solid Tumors 1.1. Progression-free survival (PFS) and overall survival (OS) were computed by Kaplan-Meier method. Results Among 30 patients who received pazopanib, 18 were pretreated (13 with other antiangiogenics). Response was evaluable in 29/30 patients. Best responses were 1 complete response, 7 partial response (PR), 17 stable disease (SD), and 4 progressions. At a 19-month median follow-up, median PFS was 13.6 months (range: 1.6–32.2+), with 59% of patients progression-free at 1 year. Median OS was not reached. Among 23 patients treated with trabectedin, all were pretreated and evaluable for response. Best responses were 1 PR, 13 SD, and 9 progressions. At a 27-month median follow-up, median PFS was 3.7 months (range: 0.7–109), with 13% of patients progression-free at 1 year. Median OS was 9.1 months. Conclusion The value of pazopanib in advanced ASPS is confirmed, with durable responses, whereas the value of trabectedin appears limited. These results are relevant to defining the best approach to advanced ASPS. Implications for Practice This retrospective study, conducted among the world reference centers for treatment of sarcoma, confirms the value of pazopanib in patients with advanced alveolar soft part sarcoma (ASPS), with dimensional and durable responses, whereas trabectedin shows a limited activity. Alveolar soft part sarcoma is resistant to conventional cytotoxic chemotherapy. Pazopanib and trabectedin are licensed for treatment of sarcoma from second line; in the lack of prospective clinical trials, these results are relevant to defining ASPS best management and strongly support initiatives aimed at obtaining the approval of pazopanib in the front line of the disease.

Summary Background Patients with advanced sarcomas have a poor prognosis and few treatment options that improve overall survival. Chemotherapy and targeted therapies offer short-lived disease control. We assessed pembrolizumab, an anti-PD-1 antibody, for safety and activity in patients with advanced soft-tissue sarcoma or bone sarcoma. Methods In this two-cohort, single-arm, open-label, phase 2 study, we enrolled patients with soft-tissue sarcoma or bone sarcoma from 12 academic centres in the USA that were members of the Sarcoma Alliance for Research through Collaboration (SARC). Patients with soft-tissue sarcoma had to be aged 18 years or older to enrol; patients with bone sarcoma could enrol if they were aged 12 years or older. Patients had histological evidence of metastatic or surgically unresectable locally advanced sarcoma, had received up to three previous lines of systemic anticancer therapy, had at least one measurable lesion according to the Response Evaluation Criteria In Solid Tumors version 1.1, and had at least one lesion accessible for biopsy. All patients were treated with 200 mg intravenous pembrolizumab every 3 weeks. The primary endpoint was investigator-assessed objective response. Patients who received at least one dose of pembrolizumab were included in the safety analysis and patients who progressed or reached at least one scan assessment were included in the activity analysis. Accrual is ongoing in some disease cohorts. This trial is registered with ClinicalTrials.gov, number NCT02301039. Findings Between March 13, 2015, and Feb 18, 2016, we enrolled 86 patients, 84 of whom received pembrolizumab (42 in each disease cohort) and 80 of whom were evaluable for response (40 in each disease cohort). Median follow-up was 17·8 months (IQR 12·3–19·3). Seven (18%) of 40 patients with soft-tissue sarcoma had an objective response, including four (40%) of ten patients with undifferentiated pleomorphic sarcoma, two (20%) of ten patients with liposarcoma, and one (10%) of ten patients with synovial sarcoma. No patients with leiomyosarcoma (n=10) had an objective response. Two (5%) of 40 patients with bone sarcoma had an objective response, including one (5%) of 22 patients with osteosarcoma and one (20%) of five patients with chondrosarcoma. None of the 13 patients with Ewing's sarcoma had an objective response. The most frequent grade 3 or worse adverse events were anaemia (six [14%]), decreased lymphocyte count (five [12%]), prolonged activated partial thromboplastin time (four [10%]), and decreased platelet count (three [7%]) in the bone sarcoma group, and anaemia, decreased lymphocyte count, and prolonged activated partial thromboplastin time in the soft-tissue sarcoma group (three [7%] each). Nine (11%) patients (five [12%] in the bone sarcoma group and four [10%] in the soft-tissue sarcoma group) had treatment-emergent serious adverse events (SAEs), five of whom had immune-related SAEs, including two with adrenal insufficiency, two with pneumonitis, and one with nephritis. Interpretation The primary endpoint of overall response was not met for either cohort. However, pembrolizumab showed encouraging activity in patients with undifferentiated pleomorphic sarcoma or dedifferentiated liposarcoma. Enrolment to expanded cohorts of those subtypes is ongoing to confirm and characterise the activity of pembrolizumab. Funding Merck, SARC, Sarcoma Foundation of America, QuadW Foundation, Pittsburgh Cure Sarcoma, and Ewan McGregor.

Solitary fibrous tumors are an uncommon sarcoma type characterized by NAB2-STAT6 gene fusion. While solitary fibrous tumors metastasize in 5-25% of cases, it has historically been challenging to determine which specific tumor and patient characteristics predict aggressive behavior. We previously reported on a novel risk stratification scheme for solitary fibrous tumors incorporating patient age, tumor size, and mitotic activity to predict risk of metastasis. Herein we validate this risk stratification scheme in an independent, lower-risk population of 79 patients with primary non-meningeal solitary fibrous tumors, and propose incorporating tumor necrosis as a fourth variable to further improve the risk score. Fifty-seven percent of cases were considered low risk, 29% intermediate risk, and 14% high risk for metastasis. Of 50 patients with sufficient clinical follow-up data, no metastases developed in the low-risk patients (n=23), while there was a 7% 10-year metastatic risk in the intermediate risk group (n=17), and a 49% 5-year metastatic risk for the high-risk patients (n=10). When tumor necrosis was added as a fourth variable to the model, predictive power was enhanced. Under the revised stratification, the proportion of tumors identified as low risk increased to 66%, with no metastasis at 10 years, intermediate risk cases comprised 24% with 10% risk of metastasis at 10 years, and high risk comprised 10% of cases with 73% risk of metastasis at 5 years. In Kaplan-Meier analysis, this fourth-variable stratification provided significant discrimination between the risk groups (P=0.0005). These findings confirmed the clinical utility of our previously published risk stratification model and support the inclusion of necrosis as a fourth variable in the model.

Purpose The ACOSOG (American College of Surgeons Oncology Group) Z9001 (Alliance) study, a randomized, placebo-controlled trial, demonstrated that 1 year of adjuvant imatinib prolonged recurrence-free survival (RFS) after resection of primary GI stromal tumor (GIST). We sought to determine the pathologic and molecular factors associated with patient outcome. Patients and Methods There were 328 patients assigned to the placebo arm and 317 to the imatinib arm. Median patient follow-up was 74 months. There were 645 tumor specimens available for mitotic rate or mutation analysis. Results RFS remained superior in the imatinib arm (hazard ratio, 0.6; 95% CI, 0.43 to 0.75; Cox model–adjusted P < .001). On multivariable analysis of patients in the placebo arm, large tumor size, small bowel location, and high mitotic rate were associated with lower RFS, whereas tumor genotype was not significantly associated with RFS. Multivariable analysis of patients in the imatinib arm yielded similar findings. When comparing the two arms, imatinib therapy was associated with higher RFS in patients with a KIT exon 11 deletion of any type, but not a KIT exon 11 insertion or point mutation, KIT exon 9 mutation, PDGFRA mutation, or wild-type tumor, although some of these patient groups were small. Adjuvant imatinib did not seem to alter overall survival. Conclusion Our findings show that tumor size, location, and mitotic rate, but not tumor genotype, are associated with the natural history of GIST. Patients with KIT exon 11 deletions assigned to 1 year of adjuvant imatinib had a longer RFS.

Introduction: The mechanistic target of rapamycin (mTOR) is a critical node at the junction of multiple intracellular signaling pathways. Amongst its many functions, mTOR instrumentally coordinates protein synthesis and cell growth in response to varying nutrient levels. The mTOR pathway has been implicated and targeted in several malignancies with modest success. Sarcomas are uncommon but diverse mesenchymal tumors for which systemic therapy is often suboptimal. Unsurprisingly, evidence is accumulating for the relevance of mTOR pathway activation across multiple sarcomas. Several clinical trials testing mTOR targeted therapy in sarcomas recently have yielded mixed results.Areas covered: The biology of the mTOR pathway and its relevance to the maintenance of the cancer phenotype shall be reviewed. The preclinical evidence for mTOR pathway activation in a range of sarcoma subtypes, the pharmacology of current and developing agents targeting mTOR, and results of completed clinical trials in sarcomas will al...

Malignant peripheral nerve sheath tumors (MPNST) are uncommon, biologically aggressive soft tissue sarcomas of neural origin that pose tremendous challenges to effective therapy. In 50% of cases, they occur in the context of neurofibromatosis type I, characterized by loss of function mutations to the tumor suppressor neurofibromin; the remainder arise sporadically or following radiation therapy. Prognosis is generally poor, with high rates of relapse following multimodality therapy in early disease, low response rates to cytotoxic chemotherapy in advanced disease, and propensity for rapid disease progression and high mortality. The last few years have seen an explosion in data surrounding the potential molecular drivers and targets for therapy above and beyond neurofibromin loss. These data span multiple nodes at various levels of cellular control, including major signal transduction pathways, angiogenesis, apoptosis, mitosis, and epigenetics. These include classical cancer-driving genetic aberrations such as TP53 and phosphatase and tensin homolog (PTEN) loss of function, and upregulation of mitogen-activated protein kinase (MAPK) and (mechanistic) target of rapamycin (TOR) pathways, as well as less ubiquitous molecular abnormalities involving inhibitors of apoptosis proteins, aurora kinases, and the Wingless/int (Wnt) signaling pathway. We review the current understanding of MPNST biology, current best practices of management, and recent research developments in this disease, with a view to informing future advancements in patient care.

Background Pazopanib (P) is approved for refractory advanced STS refractory. A retrospective study of 40 AS patients treated with P, reported a median progression-free survival (PFS) of 3.1 months and median overall survival (OS) 9.9 months (Kollar et al, Acta Oncol, 2017). Endoglin is an essential angiogenic receptor expressed on AS cells that is upregulated following VEGF inhibition. TRC105, an endoglin antibody, combined with P produced a median PFS of 7.8 months in chemotherapy-refractory and P-naive patients enrolled on a phase I-II trial. Methods TAPPAS was a randomized multicenter trial of TRC105/P vs P that enrolled cutaneous and non-cutaneous AS patients and incorporated an adaptive enrichment design. Key inclusion criteria: 0-2 prior lines of therapy, ECOG ≤ 1. The primary endpoint was PFS by RECIST 1.1 by independent radiographic review (+ cutaneous lesions by photography) (IRR). Secondary endpoints included PFS by investigator review (INV) and OS. An interim analysis to determine the final sample size was conducted following enrollment of 123 patients. Results Of 123 pts (TRC105/P, 62; P, 61), 60% were female, 89% were white; median age was 68 years (range: 24-82); 46% were ECOG PS 0; 50% had cutaneous disease; and 28% had no prior treatment. TRC105/P did not prolong median PFS or OS compared to P (Table). Most common all-grade adverse events (AEs) in TRC105/P vs P: fatigue (61% vs 55%); headache (64% vs 23%), diarrhea (57% vs 51%), nausea (48% vs 49%), vomiting (38% vs 23%), anemia (44% vs 9.4%), epistaxis (56% vs 3.8%) & hypertension (36% vs.55%). Table . 1667O P TRC105/P Median PFS, mo (95% CI), IRR 4.3 (2.9-NE) 4.2 (2.8-8.3) HR (95% CI) 0.98 (0.52-1.8) p-value 0.95 Median PFS, mo (95% CI), Investigator 2.9 (2.6-4.1) 3.9 (2.6-5.5) HR (95% CI) 0.77 (0.46-1.78) p-value 0.31 Median PFS, cutaneous, mo (95% CI), IRR 5.6 (2.6-5.6) 4.2 (2.8-8.3) HR (95% CI) 1.07 (0.43, 2.7) p-value 0.89 Overall Survival, mo (95% CI) 8.7 (7.4, NE) NE (6.8, NE) Odds ratio (95% CI) 0.90 (0.46, 1.74) p-value 0.74 Overall Survival, cutaneous, mo (95% CI) 8.0 (6.7, NE) NE (6.8, NE) Odds ratio (95% CI) 0.68 (0.25, 1.84) p-value 0.45 NE: not estimable; CI: confidence interval; mo: months Conclusions TRC105 did not demonstrate activity when combined with P in angiosarcoma. This was the 1st randomized phase III trial in angiosarcoma. These data provide a benchmark of the activity of P in 1st + 2nd-line setting in AS. A number of patients derived durable benefit from the combination schedule, indicating the heterogeneity of angiosarcomas. Clinical trial identification NCT 02979899. Legal entity responsible for the study Tracon Pharmaceuticals, Inc. Funding Tracon Pharmaceuticals, Inc. Disclosure R.L. Jones: Advisory / Consultancy: Tracon; Advisory / Consultancy: Adaptimmune; Advisory / Consultancy: Blueprint; Advisory / Consultancy: Clinigen; Advisory / Consultancy: Deciphera; Advisory / Consultancy: Daichii; Advisory / Consultancy: Eisai; Advisory / Consultancy: Epizyme; Advisory / Consultancy: PharmaMar; Advisory / Consultancy: Lilly; Advisory / Consultancy: Merck. L. Liu: Full / Part-time employment: Tracon. C. Theuer: Full / Part-time employment: Tracon. All other authors have declared no conflicts of interest.

Background: CIVO microdosing studies performed in patient tumors in situ allow drug developers to assess localized tumor and microenvironment responses to multiple agents without having to expose patients to high systemic drug levels. By concentrating microdoses of multiple different drugs within a living tumor in situ, it is possible to compare tumor and immune responses in spatially resolved regions of the same tumor. This type of early phase (Phase 0) clinical study represents a new path for drug developers to gain insight into drug efficacy, tumor associated immune cell modulation, biomarker discovery and validation, and microenvironment interactions for new drugs earlier in the drug development process. Traditionally, analysis of FFPE samples from these microdosing studies involve routine immunohistochemistry, immunofluorescence, and in situ assays that reveal changes in protein and RNA expression. These assays offer tissue wide protein and gene expression information but have limited multiplexing capabilities and dynamic range, as well as rapidly consume precious trial samples. Novel technologies such as NanoString’s GeoMxTM Digital Spatial Profiler (DSP) enable high-plex spatially resolved analysis of proteins and RNA transcripts in single FFPE tissue sections. In this proof of principle study, we utilized GeoMxTM Digital Spatial Profiler for protein and RNA expression on single FFPE sections from patient sarcoma tumors that were microdosed with multiple FDA approved drugs. Methods: Single FFPE sections from microdosed patient tumor samples were IF stained for DNA and CD3 and whole slide imaged. 600-micron and 100-micron diameter regions of interests (ROIs) were selected for DSP analysis within drug and control microinjection sites. Imaging and barcode counts were performed using GeoMxTM DSP and nCounter systems. Results: DSP protein analysis highlighted phospho-S6 and phospho-ERK upregulation in response to doxorubicin compared to vehicle site. Additionally, ROIs sampled along the doxorubicin exposure gradient showed a dose-dependent reduction of phosphorylation of both S6 and ERK proteins. DSP RNA analysis revealed drug specific transcript regulation of multiple genes in microdosed tumors, including upregulation of chemokines CXCL9 and CXCL10 at sites of doxorubicin and aldesleukin injection but not to other chemotherapy agents. Conclusions: Early phase CIVO microdosing studies combined with high-plex DSP opens the door to generating multi-omics data for multiple microdosed drugs within small patient studies. Analysis of protein and RNA expression using DSP enabled collection of targeted region of interest high density data from single FFPE sections, conserving precious patient biopsy samples. Through continued expansion of the GeoMxTM DSP analyte panels, collecting an ever-increasing depth of protein and gene expression data is possible in Phase 0 CIVO microdosing studies. Citation Format: Gary B. Deutsch, Seth M. Pollack, Matthew J. Thompson, Kenneth R. Gundle, Jessica A. Bertout, Jason P. Frazier, Emily Beirne, Marc O. Grenley, JingJing Gong, Yan Liang, Joseph M. Beechem, Richard A. Klinghoffer, Robert G. Maki. High-plex spatial profiling analysis of multidrug CIVO microdose studies in cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2155.

11015 Background: Immune checkpoint inhibitors have demonstrated activity in multiple tumor types but their activity in soft tissue sarcomas remains limited. In the multicenter phase II study, SARC028, the anti-PD-1 antibody, P demonstrated objective responses that were largely restricted to UPS and LPS subtypes. We now report outcomes from 2 expansion cohorts of SARC 028 in advanced UPS and LPS. Methods: To further confirm the clinical activity of P in UPS and LPS, we enrolled an additional 30 pts in each of 2 expansion cohorts for a total of 40 UPS and 40 LPS pts. Primary endpoint was investigator-assessed response by RECIST v1.1. Secondary endpoints were safety, progression-free survival (PFS), 12-week PFS rate, and overall survival (OS). An ORR of 25% was considered clinically meaningful and < 10% was considered to show lack of efficacy. P was to be considered a success if 8 or more of 40 enrolled patients had a PR or better (1-sided α = 0.042, 82% power). Pts age ≥18 with advanced, refractory UPS or LPS received 200 mg of P IV every 3 weeks until progression or unacceptable toxicity. Results: Preliminary results from the first 10 pts in each of the UPS and LPS cohorts have been reported. We now present summary data after enrolling an additional 30 pts in each cohort. The ORR in the UPS cohort was 23% (9/40), with an additional 5/30 PRs observed in the expansion cohort (total 2 CRs, 7 PRs). In the LPS cohort, the ORR was 10% (4/39 evaluable pts), with an additional 2/30 PRs observed (total 4 PRs). Median PFS for the UPS group was 3 months [95% CI: 2, 5] and 2 months [95% CI: 2, 4] for the LPS group. 12-week PFS rate was 50% in UPS [95% CI: 35, 65] and 44% in LPS [95% CI: 28, 60]. The UPS group had a median OS of 12 months [95% CI: 7, 34] and 13 months [95% CI: 8, NR] for the LPS group. P was well tolerated with no unexpected toxicities. Conclusions: The UPS cohort achieved its primary endpoint, however the activity of P in UPS deserves further evaluation in a randomized study. The activity of P was not confirmed in the LPS cohort. Ongoing biomarker analyses may direct better patient selection and guide future combination strategies. Clinical trial information: NCT02301039.

2508 Background: We present initial safety, pharmacokinetics (PK), and efficacy from the dose escalation study of R3767, alone (mono) or in combination with cemiplimab (REGN2810), a PD-1 mAb (combo), in pts with advanced malignancies (NCT03005782). Methods: Pts who had progressed on prior therapy(ies) and/or for whom no therapy with clinical benefit was available were enrolled; most pts had received no prior anti-PD-1/PD-L1. Pts received R3767 1, 3, 10, or 20 mg/kg every 3 weeks (Q3W) ± cemiplimab 3 mg/kg or 350 mg Q3W IV for ≤51 weeks. Crossover from mono to combo was allowed at progression. R3767 PK were evaluated. Tumor measurements were performed Q6W for the first 24 weeks and subsequently Q9W. Data cut-off date was Aug 25, 2018. Results: Mono: 27 pts (median age: 66 yr; ECOG PS: 0 [n=4], 1 [n=23]) were treated. There were no dose-limiting toxicities (DLTs). The most common treatment-emergent adverse event (TEAE) was nausea (22.2%). Grade ≥3 immune-related adverse events (irAEs) of increased alanine and aspartate aminotransferases (each 3.7%) were reported. By investigator-assessment (per RECIST 1.1; INV), best response was stable disease in 11 pts. Combo: 42 pts (median age: 60 yr; ECOG PS: 0 [n=15], 1 [n=27]) were treated. One pt treated with R3767 3 mg/kg Q3W + cemiplimab 3 mg/kg Q3W experienced DLT of grade 4 elevated blood creatine phosphokinase, associated with grade 3 myasthenia syndrome and grade 1 elevated troponin. The most common TEAEs were fatigue (33.3%) and nausea (21.4%). Grade 3 irAE of hypothyroidism (2.4%) was also reported. By INV, 2 (both small cell lung cancer) combo pts and 2 (endometrial cancer and cutaneous squamous cell carcinoma) of 12 additional pts who crossed over from mono to combo had partial responses. PK: R3767 concentrations in serum increased in a dose-dependent manner and were unaffected by combo. Conclusions: The safety profile of R3767 ± cemiplimab was generally tolerable; PK was linear. Early efficacy signals were detected despite the difficult-to-treat pt population. Biomarker studies are ongoing. R3767 20 mg/kg or 1600 mg fixed dose equivalent Q3W as mono and combo were selected for further evaluation. Clinical trial information: NCT03005782.

11011 Background: CMB305 (C) is an immunotherapy designed to generate an anti-NY-ESO-1 immune response (IR). C consists of a dendritic cell-targeting lentiviral vector encoding NY-ESO-1 gene (LV305), and a TLR-4 agonist NY-ESO-1 recombinant protein plus GLA-SE (G305). A Phase 1 study demonstrated C is safe, generates IR and conveys a median overall survival (mOS) of 23.7 months (15.5, not reached [NR]) for soft tissue sarcomas & 29.2 months (12.2, NR) for synovial sarcoma (SS) (ESMO 2018). We evaluated efficacy and safety of C and atezolizumab (A) vs A alone in NY-ESO-1+ SS and myxoid round cell liposarcoma (MRCL). Methods: A prospective randomized open label phase 2 study of C (LV305 Intradermal Days 0, 14, 42, 70 + G305 Intramuscular Days 28, 56, 84 then q 6wk up to one year (yr)) + A (1200mg IV q3wk) vs A alone in advanced NY-ESO-1+ SS/MRCL. Primary endpoints of OS and progression-free survival (PFS); secondary endpoints of safety, IR, and response rate and post hoc analysis by line of therapy. Results: 88 patients (pts) were enrolled and dosed. Arm C+A: median age 48 yrs, 73% SS, 98% relapsed metastatic, 73% ≥2 prior lines chemotherapy; Arm A: 47 yrs, 67% SS, 84% relapsed metastatic, 53% ≥2 prior lines chemotherapy. Most treatment-related adverse events (TRAE) Grade 1/2, no treatment related deaths. Summary of clinical outcomes. Conclusions: Despite no major differences in PFS and OS between the treatment arms (Arm C+A had more advanced disease and more prior lines of chemotherapy), Arm A +C achieved PRs, a higher level of anti-NY-ESO-1 IR, and pts with IR had numerically superior outcomes. Moreover, the clinical benefit of C+A in earlier lines of therapy warrant further study. Clinical trial information: NCT02609984. [Table: see text]

We describe a case of a 44-year-old woman with locally advanced aggressive angiomyxoma with a novel translocation high-mobility group AT-hook 2–yes-associated protein 1 (HMGA2-YAP1) fusion, implying a t(11;12)(q22.1;q14.3) translocation. She was started on gonadotropin-releasing hormone agonist injection and an aromatase inhibitor for persistent disease, which responded to treatment; she was subsequently treated with radiation before a more definitive operation was conducted. This case report indicates that HGMA2-YAP1–translocated aggressive angiomyxoma is responsive to oestrogen antagonism and hopefully will allow for the development of diagnostics useful for this rare but often morbid neoplasm. This case also highlights the importance of appropriate workup of a soft tissue mass.

Although benign hemangiomas are among the most common diagnoses among connective tissue tumors, angiosarcomas and other sarcomas arising from blood vessels are rare, even among sarcomas. Because endothelial tumors have unique embryonal derivation compared with other sarcomas, it is not surprising they have unique characteristics. Herein are reviewed some of these unique characteristics and therapeutic options for patients with some of these diagnoses, highlighting the potential of new agents for these tumors, which will in all likelihood also impact treatment on more common cancers.

Background: This retrospective pooled analysis assessed the effect of age on the efficacy and safety of trabectedin in young and elderly patients with recurrent advanced soft tissue sarcoma (STS). Methods: Data from 350 adults with STS treated in five phase II trials with trabectedin were divided in the younger (

OBJECTIVE: To conduct the first adjuvant trial of imatinib mesylate for treatment of gastrointestinal stromal tumor (GIST). BACKGROUND: GIST is the most common sarcoma. Although surgical resection has been the mainstay of therapy for localized, primary GIST, postoperative tumor recurrence is common. The KIT protooncogene or, less frequently, platelet-derived growth factor receptor alpha is mutated in GIST; the gene products of both are inhibited by imatinib mesylate. METHODS: This was a phase II, intergroup trial led by the American College of Surgeons Oncology Group, registered at ClinicalTrials.gov as NCT00025246. From September 2001 to September 2003, we accrued 106 patients who had undergone complete gross tumor removal but were deemed at high risk for recurrence. Patients were prescribed imatinib 400 mg per day for 1 year and followed with serial radiologic evaluation. The primary endpoint was overall survival (OS). RESULTS: After a median follow-up of 7.7 years, the 1-, 3-, and 5-year OS rates were 99%, 97%, and 83%, which compared favorably with a historical 5-year OS rate of 35%. The 1-, 3-, and 5-year recurrence-free survival (RFS) rates were 96%, 60%, and 40%. On univariable analysis, age and mitotic rate were associated with OS. On multivariable analysis, the RFS rate was lower with increasing tumor size, small bowel site, KIT exon 9 mutation, high mitotic rate, and older age. CONCLUSIONS: Adjuvant imatinib in patients with primary GIST who are at high risk of recurrence prolongs OS compared with that of historical controls. Optimal duration of adjuvant therapy remains undefined. (NCT00025246).

Lymphangiomatosis, a rare disorder of the lymphatic system characterized by the abnormal proliferation of lymphatic vessels, is a typically benign disorder that at times can exhibit invasive or malignant behavior. While generally considered a diagnosis of childhood, in adults the majority of cases are asymptomatic and found incidentally. Rarely, lymphatic overgrowth can occur, causing growth of lesions on imaging mimicking a metastatic process and occasionally, resulting in substantial morbidity and mortality. Here, we present such a case of lymphangiomatosis with multi-organ system involvement in liver, bone, and spleen. In addition to details of the clinical presentation and the pathologic review which led to the diagnosis, we describe our use of the tyrosine kinase inhibitor pazopanib, which may cause stabilization of lymphangiomatosis through blockade of vascular endothelial growth factor (VEGF) signaling, for systemic treatment in this unusual case.

Patients with chronic myelogenous leukemia (CML) or gastrointestinal stromal tumors (GIST) who take imatinib have abnormalities of bone metabolism. However, it is unclear what impact these changes have on bone mineral density (BMD). We prospectively analayzed levels of osteocalcin, a marker of bone formation secreted by osteoblasts, and serum N-telopeptide of type I collagen (NTX), a marker of bone resorption, as well as other minerals involved in bone metabolism in 19 patients with either CML or GIST We correlated these results with changes in bone mineral density as measured by serial dual energy X-ray absorptiometry (DEXA) scans over a two year period. Osteocalcin levels were low in 95% of patients and 37% had no measurable amount. Levels of NTX were less consistent. Nine patients (47%) had a decrease in BMD, four patients (2%) had an increase in BMD, and six patients (32%) had no change. There was no correlation between metabolic markers and change in BMD. We suggest that ongoing management of patients who take imatinib should include monitoring of bone health on a long term basis.

Summary Background Preclinical studies have shown synergistic antitumour activity by inhibition of insulin-like growth factor-1 receptor (IGF-1R) and mTOR. The expression of IGF-1R seems to be crucial for this effect. We investigated the safety and efficacy of the combination of the IGF-1R antibody cixutumumab and the mTOR inhibitor temsirolimus in patients with chemotherapy-refractory bone and soft-tissue sarcomas according to IGF-1R expression by immunohistochemistry. Methods We undertook a multicentre, open-label, phase 2 study in 19 cancer centres in the USA. Patients aged at least 16 years with a histologically confirmed diagnosis of bone or soft-tissue sarcoma were allocated on the basis of IGF-1R expression by immunohistochemistry to one of three treatment groups: IGF-1R-positive soft-tissue sarcoma (group A), IGF-1R-positive bone sarcomas (group B), or IGF-1R-negative bone and soft-tissue sarcoma (group C). Patients received weekly treatment with cixutumumab (6 mg/kg, intravenous) and temsirolimus (25 mg, intravenous flat dose) in 6-week cycles. A Simon optimal two-stage design was used for every arm. The primary endpoint was progression-free survival (PFS) at 12 weeks by intention-to-treat analysis in the first 54 patients assigned to every treatment arm. Although patients still remain on treatment, this trial has completed enrolment and this represents the final analysis. This study is registered with ClinicalTrials.gov, number NCT01016015. Findings Between Nov 18, 2009, and April 11, 2012, 388 patients were screened for IGF-1R expression and 54 were assigned to each arm. 17 of 54 patients in the IGF-1R-positive soft-tissue sarcoma group (31%; one-sided 95% CI lower bound 21%; two-sided 90% CI 21–43), 19 of 54 in IGF-1R-positive bone sarcoma group (35%; one-sided 95% CI lower bound 24%; two-sided 90% CI 24–47), and 21 of 54 in the IGF-1R-negative group (39%, one-sided 95% CI lower bound 28%; two-sided 90% CI 28–51) were progression free at 12 weeks. On April 6, 2011, the protocol was amended to include three additional patients in the IGF-1R-positive soft-tissue sarcoma group (total of 57 patients) and nine more in the IGF-1R-negative group (total of 63 patients). There were 2546 adverse events reported during the study, 214 (8%) of which were grade 3–4. The most common grade 3–4 toxicities in the 174 treated patients were anaemia in 16 (9%) patients, hyperglycaemia in 18 (10%), hypophosphataemia in 16 (9%), lymphopenia in 25 (14%), oral mucositis in 19 (11%), and thrombocytopenia in 19 (11%). Interpretation The combination of cixutumumab and temsirolimus shows clinical activity in patients with sarcoma and forms a basis for future trials. However, IGF-1R expression by immunohistochemistry is not predictive of clinical outcome after treatment with this combination. Funding National Cancer Institute and CycleforSurvival Fund, Memorial Sloan-Kettering Cancer Center.

BACKGROUND: HSP90 inhibition leads to proteosomal degradation of activated KIT and has in vitro activity against gastrointestinal stromal tumors (GIST). BIIB021 is an oral non-ansamycin HSP90 inhibitor. We carried out a phase II study of BIIB021 in patients with GIST refractory to imatinib and sunitinib. PATIENTS AND METHODS: The primary end-point was metabolic partial response (mPR) as assessed by fluorodeoxyglucose positron emission tomography (FDG-PET). The secondary end-points were pharmacokinetic assessments of BIIB021 and pharmacodynamic assessments of HSP70. Twenty-three patients were treated on two schedules: 12 pts received 600 mg twice a week (BIW) and 11 patients received 400 mg three times a week (TIW). All had prior imatinib and sunitinib but stopped>14 days before starting BIIB021. RESULTS: The median age was 59 years (33-88 years), 61% male, 44% Eastern Cooperative Oncology Group 1 (ECOG1). The best response was PR by FDG-PET for five patients (3/12 at 600 mg BIW and 2/9 at 400 TIW) for an overall response rate of 22%. The response duration was 25-138 days. Adverse events (AEs) were mild to moderate. The mean Cmax was 1.5 micromol and the mean AUC was 2.9 micromol h. Cmax>1.5 micromol was associated with a decrease in standardized uptake value (SUVmax). HSP70 increased substantially following treatment. CONCLUSIONS: This study met its primary end-point. BIIB021 leads to objective responses in refractory GIST patients. Pharmacodynamic studies confirmed HSP90 inhibition. Further evaluation of BIIB021 in GIST is warranted.

Background. Patients with recurrent synovial sarcomas have few options for systemic therapy. Since they express large amounts of endogenous CT (cancer testis) antigens such as NY-ESO-1, we investigated the clinical activity of single agent anti-CTLA4 antibody ipilimumab in patients with advanced or metastatic synovial sarcoma.Methods. A Simon two-stage phase II design was used to determine if there was sufficient activity to pursue further. The primary endpoint was tumor response rate by RECIST 1.0. Patients were treated with ipilimumab 3 mg/kg intravenously every 3 weeks for three cycles and then restaged. Retreatment was possible for patients receiving an extra three-week break from therapy. Sera and peripheral blood mononuclear cells were collected before and during therapy to assess NY-ESO-1-specific immunity.Results. Six patients were enrolled and received 1–3 cycles of ipilimumab. All patients showed clinical or radiological evidence of disease progression after no more than three cycles of therapy, for a RECIST response rate of 0%. The study was stopped for slow accrual, lack of activity, and lack of immune response. There was no evidence of clinically significant either serologic or delayed type hypersensitivity responses to NY-ESO-1 before or after therapy.Conclusion. Despite high expression of CT antigens by synovial sarcomas of patients treated in this study, there was neither clinical benefit nor evidence of anti-CT antigen serological responses. Assessment of the ability of synovial sarcoma cell lines to present cancer-germ cell antigens may be useful in determining the reason for the observed lack of immunological or clinical activity.

Human leukocyte antigen class I (HLA-I) down-regulation has been reported in many human cancers to be associated with poor clinical outcome. However, its connection to tumor-initiating cells (TICs) remains unknown. In this study, we report that HLA-I is down-regulated in a subpopulation of cells that have high tumor initiating capacity in different types of human sarcomas. Detailed characterization revealed their distinct molecular profiles regarding proliferation, apoptosis and stemness programs. Notably, these TICs can be induced to differentiate along distinct mesenchymal lineages, including the osteogenic pathway. The retinoic acid receptor signaling pathway is overexpressed in HLA-1 negative TICs. All-trans retinoic acid treatment successfully induced osteogenic differentiation of this subpopulation, in vitro and in vivo, resulting in significantly decreased tumor formation. Thus, our findings indicate down-regulated HLA-I is a shared feature of TICs in a variety of human sarcomas, and differentiation therapy strategies may specifically target undifferentiated TICs and inhibit tumor formation.

Purpose Palifosfamide is the active metabolite of ifosfamide and does not require prodrug activation, thereby avoiding the generation of toxic metabolites. The PICASSO III trial compared doxorubicin plus palifosfamide with doxorubicin plus placebo in patients who had received no prior systemic therapy for metastatic soft tissue sarcoma. Patients and Methods Patients were randomly assigned 1:1 to receive doxorubicin 75 mg/m2 intravenously day 1 plus palifosfamide 150 mg/m2/d intravenously days 1 to 3 or doxorubicin plus placebo once every 21 days for up to six cycles. The primary end point was progression-free survival (PFS) by independent radiologic review. Results In all, 447 patients were randomly assigned to receive doxorubicin plus palifosfamide (n = 226) or doxorubicin plus placebo (n = 221). Median PFS was 6.0 months for doxorubicin plus palifosfamide and 5.2 months for doxorubicin plus placebo (hazard ratio, 0.86; 95% CI, 0.68 to 1.08; P = .19). Median overall survival was 15.9 months for doxorubicin plus palifosfamide and 16.9 months for doxorubicin plus placebo (hazard ratio, 1.05; 95% CI, 0.79 to 1.39; P = .74). There was a higher incidence of grade 3 to 4 adverse events in the doxorubicin plus palifosfamide arm (63.6% v 50.9%) including a higher rate of febrile neutropenia (21.4% v 12.6%). Conclusion No significant difference in PFS was observed in patients receiving doxorubicin plus palifosfamide compared with those receiving doxorubicin plus placebo. The observed median PFS and overall survival in this large, international study can serve as a benchmark for future studies of doxorubicin in metastatic soft tissue sarcoma.

Summary Background A non-randomised, phase 2 study showed activity and tolerability of eribulin in advanced or metastatic soft-tissue sarcoma. In this phase 3 study, we aimed to compare overall survival in patients with advanced or metastatic soft-tissue sarcoma who received eribulin with that in patients who received dacarbazine (an active control). Methods We did this randomised, open-label, phase 3 study across 110 study sites in 22 countries. We enrolled patients aged 18 years or older with intermediate-grade or high-grade advanced liposarcoma or leiomyosarcoma who had received at least two previous systemic regimens for advanced disease (including an anthracycline). Using an interactive voice and web response system, an independent statistician randomly assigned (1:1) patients to receive eribulin mesilate (1·4 mg/m 2 intravenously on days 1 and 8) or dacarbazine (850 mg/m 2 , 1000 mg/m 2 , or 1200 mg/m 2 [dose dependent on centre and clinician] intravenously on day 1) every 21 days until disease progression. Randomisation was stratified by disease type, geographical region, and number of previous regimens for advanced soft-tissue sarcoma and in blocks of six. Patients and investigators were not masked to treatment assignment. The primary endpoint was overall survival in the intention-to-treat population. The study is registered with ClinicalTrials.gov, number NCT01327885, and is closed to recruitment, but treatment and follow-up continue. Findings Between March 10, 2011 and May 22, 2013, we randomly assigned patients to eribulin (n=228) or dacarbazine (n=224). Overall survival was significantly improved in patients assigned to eribulin compared with those assigned to dacarbazine (median 13·5 months [95% CI 10·9–15·6] vs 11·5 months [9·6–13·0]; hazard ratio 0·77 [95% CI 0·62–0·95]; p=0·0169). Treatment-emergent adverse events occurred in 224 (99%) of 226 patients who received eribulin and 218 (97%) of 224 who received dacarbazine. Grade 3 or higher adverse events were more common in patients who received eribulin (152 [67%]) than in those who received dacarbazine (126 [56%]), as were deaths (10 [4%] vs 3 [1%]); one death (in the eribulin group) was considered treatment-related by the investigators. Interpretation Overall survival was improved in patients assigned to eribulin compared with those assigned to an active control, suggesting that eribulin could be a treatment option for advanced soft-tissue sarcoma. Funding Eisai.

The principal management of primary soft tissue sarcoma is surgical resection. The clinical goal is resection with negative margins, preferably that extend 2 cm from the grossly determined border. This can be difficult to assess and is often limited by the presence of major neurovascular and bony structures. The majority of soft tissue sarcomas do not invade into bone unless there has been previous injury to bone or the lesion has an epithelioid component, such as synovial sarcoma.