Regorafenib in advanced solitary fibrous tumour: Results from an exploratory phase II clinical study.

BACKGROUND: To investigate the activity of regorafenib in advanced solitary fibrous tumour (SFT). METHODS: An Italian monocentric investigator-initiated exploratory single-arm Phase II trial was conducted of regorafenib in adult patients with advanced and progressive SFT, until progression or limiting toxicity. Prior treatment with antiangiogenics was allowed. Primary and secondary end-points were: overall response rate (ORR) by Choi criteria, and ORR by RECIST, progression-free survival (PFS), overall survival (OS). RESULTS: From January 2016 to February 2021, 18 patients were enroled [malignant-SFT = 13; dedifferentiated-SFT (D-SFT) = 4; typical-SFT (T-SFT) = 1]. Fourteen patients were pre-treated, in 12 cases with antiangiogenics (median [m-] lines of treatment = 3). Sixteen patients were evaluable for response (one screening failure; one early discontinuation). Six/16 (35.2%) required a definitive dose reduction. ORR by Choi was 37.5% (95% CI: 15.2-64.6), with 6/16 (37.5%) partial responses (PR), 6/16 (37.5%) stable disease (SD) and 4/16 (25%) progressions; 5/6 responses occurred in patients pre-treated with antiangiogenics. No responses were detected in D-SFT. Best RECIST responses were: 1/16 (6.2%) PR, 12/16 (75%) SD, 3/16 (18.8%) progressions. At 48.4 month m-FU, m-PFS by Choi was 4.7 (inter-quartile range: 2.4-13.1) months, with 31.2% patients progression-free at 1 year. CONCLUSION: Regorafenib showed activity in SFT, with 30% patients free-from-progression at one year. Responses were observed also in patients pretreated and refractory to another antiangiogenic agents. However, ORR and m-PFS were lower than reported with other antiangiogenics, and this was possibly due to discrepancies in the patient population and the high-rate of dose reductions.

Locally advanced malignant solitary fibrous tumour successfully treated with conversion chemotherapy, operation and postoperative radiotherapy: a case report.

Preoperative diagnosis of solitary fibrous tumour (SFT) may not provide a complete tumour picture and may be inaccurate. There is no standard treatment for locally advanced or metastasised malignant SFT (MSFT). Here, the case of a 17-year-old male patient with final pathology diagnosis of MSFT is reported. Preoperative biopsy pathology results suggested an Ewing sarcoma that was positive for CD99 antigen, vimentin, friend leukaemia integration 1 transcription factor, apoptosis regulator Bcl-2, and synaptophysin; and negative for CD34 antigen, S-100 protein (S-100), smooth muscle antigen, cytokeratin, and Wilms tumour 1 associated protein. The Ki67 positive rate was 8%, so the patient initially received eight cycles of conversion chemotherapy (vincristine, etoposide, ifosfamide and pirarubicin for one cycle, and vincristine, doxorubicin, and cyclophosphamide/ifosfamide and etoposide for 7 cycles in total). The tumour shrunk significantly and was surgically removed. The final pathology diagnosis was MSFT that was positive for CD99 and signal transducer and activator of transcription 6, and negative for CD34, tumour protein 63, S-100, desmin, and epithelial membrane antigen. Fluorescence in situ hybridization showed no gene translocation in EWS RNA binding protein 1, SS18 subunit of BAF chromatin remodelling complex or FUS RNA binding protein. The patient finally accepted adjuvant radiotherapy of 5600 cGy. Disease-free survival has been > 1 year, with no recurrence or metastasis detected to date. MSFT is rare and treatment for locally advanced or metastatic MSFT remains controversial. The efficacy of the present therapeutic strategy requires further research.

SEOM Clinical Guideline of management of soft-tissue sarcoma (2020).

Soft-tissue sarcomas constitute an uncommon and heterogeneous group of tumors of mesenchymal origin. Diagnosis, treatment, and management should be performed by an expert multidisciplinary team. MRI/CT of the primary tumor and biopsy is mandatory before any treatment. Wide surgical resection with tumor-free tissue margin is the mainstay for localized disease. Radiotherapy is indicated in large, deep, high-grade tumors, or after marginal resection not suitable for re-excision. Perioperative chemotherapy should be discussed for high-risk sarcomas of the extremities and trunk-wall. In the case of oligometastatic disease, patients should be considered for local therapies. First-line treatment with anthracyclines (or in combination with ifosfamide) is the treatment of choice. Other drugs have shown activity in second-line therapy and in specific histological subtypes but options are limited and thus, a clinical trial should always be discussed.

Solitary fibrous tumor/hemangiopericytoma treated with temozolomide plus bevacizumab: a report of four cases and literature review.

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare tumor derived from mesenchymal tissue. Although standard chemotherapy for SHT/HPC has not been established, temozolomide plus bevacizumab (TMZ+Bev) therapy for SFT/HPC has been reported. The effectiveness and safety of TMZ+Bev (temozolomide 150 mg/m2 orally on days 1-7 and days 15-21 and bevacizumab 5 mg/kg intravenously on day 8 and day 22 on a 28-day cycle), which was administered from December 2013 until April 2019 to four patients with SFT/HPC, were retrospectively analyzed. Four patients with SFT/HPC received TMZ+Bev. The age of the patients ranged from 41 to 75 years. Two were male, and the primary tumor sites were the meninges in three patients and the pleura in one. One achieved partial response; the others, stable disease (SD). The progression-free survival time ranged from 9.4 to 29.6 months according to RECIST v1.1. One patient died 59 months after using TMZ+Bev, and the others survived for 17 to 64 months. All patients experienced Grade 3 or higher lymphopenia, and three had Grade 3 or higher leukopenia and neutropenia. One patient subsequently received doxorubicin; another, pazopanib. TMZ+Bev therapy for SFT/HPC is safe and effective for maintaining long-term SD.

Pazopanib for treatment of typical solitary fibrous tumours: a multicentre, single-arm, phase 2 trial.

BACKGROUND: Solitary fibrous tumour is an ultra-rare sarcoma, which encompasses different clinicopathological subgroups. The dedifferentiated subgroup shows an aggressive course with resistance to pazopanib, whereas in the malignant subgroup, pazopanib shows higher activity than in previous studies with chemotherapy. We designed a trial to test pazopanib activity in two different cohorts of solitary fibrous tumour: the malignant-dedifferentiated cohort, which was previously published, and the typical cohort, which is presented here. METHODS: In this single-arm, phase 2 trial, adult patients (aged ≥18 years) diagnosed with confirmed metastatic or unresectable typical solitary fibrous tumour of any location, who had progressed in the previous 6 months (by Choi criteria or Response Evaluation Criteria in Solid Tumors [RECIST]) and an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 were enrolled at 11 tertiary hospitals in Italy, France, and Spain. Patients received pazopanib 800 mg once daily, taken orally, until progression, unacceptable toxicity, withdrawal of consent, non-compliance, or a delay in pazopanib administration of longer than 3 weeks. The primary endpoint was proportion of patients achieving an overall response measured by Choi criteria in patients who received at least 1 month of treatment with at least one radiological assessment. All patients who received at least one dose of the study drug were included in the safety analyses. This study is registered in ClinicalTrials.gov, NCT02066285, and with the European Clinical Trials Database, EudraCT 2013-005456-15. FINDINGS: From June 26, 2014, to Dec 13, 2018, of 40 patients who were assessed, 34 patients were enrolled and 31 patients were included in the response analysis. Median follow-up was 18 months (IQR 14-34), and 18 (58%) of 31 patients had a partial response, 12 (39%) had stable disease, and one (3%) showed progressive disease according to Choi criteria and central review. The proportion of overall response based on Choi criteria was 58% (95% CI 34-69). There were no deaths caused by toxicity, and the most frequent adverse events were diarrhoea (18 [53%] of 34 patients), fatigue (17 [50%]), and hypertension (17 [50%]). INTERPRETATION: To our knowledge, this is the first prospective trial of pazopanib for advanced typical solitary fibrous tumour. The manageable toxicity and activity shown by pazopanib in this cohort suggest that this drug could be considered as first-line treatment for advanced typical solitary fibrous tumour. FUNDING: Spanish Group for Research on Sarcomas (GEIS), Italian Sarcoma Group (ISG), French Sarcoma Group (FSG), GlaxoSmithKline, and Novartis.

Efficacy of bevacizumab and temozolomide therapy in locally advanced, recurrent, and metastatic malignant solitary fibrous tumour: A population-based analysis.

BACKGROUND: Patients with locally advanced, recurrent or metastatic solitary fibrous tumour are often treated with bevacizumab and temozolomide based on the clinical efficacy reported in a case series of 14 patients. Given the rarity of solitary fibrous tumour, large trials are not feasible. We report the efficacy of this regimen based on a population-based analysis. METHODS: This was a population-based retrospective, multi-centre analysis using patient data from a provincial cancer registry and treatment database. Cases from June 2006 through October 2016 were identified for patients receiving bevacizumab and temozolomide for locally advanced, recurrent or metastatic solitary fibrous tumour or hemangiopericytoma, which is sometimes used to describe tumours arising from the meninges. The primary outcome was overall response rate. Secondary outcomes included time to response, progression free survival and overall survival estimated using the Kaplan-Meier method. RESULTS: Fourteen patients were identified: median age 59 (range 44-70), male 78.6%. Diagnoses were solitary fibrous tumour in 10 (71.4%) and hemangiopericytoma in four (28.6%), with metastatic disease in 10 (72.7%) patients. The most common primary sites were meninges in four (28.6%) and pelvis in three (21.4%) patients. The median follow-up was 15.5 months, with median treatment of four months. Overall response rate was 21.4% (no complete response, 3 partial response), with median time to response of four months. Median progression free survival, six-month progression free survival and overall survival were 17 months, 65.0%, and 45 months, respectively. CONCLUSIONS: Efficacy of bevacizumab and temozolomide in solitary fibrous tumour appeared to be similar to that previously reported. Our findings confirmed that bevacizumab and temozolomide is an effective and tolerated treatment for this patient population.

Activity of axitinib in progressive advanced solitary fibrous tumour: Results from an exploratory, investigator-driven phase 2 clinical study.

BACKGROUND: To explore the activity of axitinib in advanced solitary fibrous tumour (SFT). PATIENTS AND METHODS: In this investigator-driven phase II study on axitinib in advanced and progressive SFT, patients received axitinib, 5 mg bis in day (BID), until progression or limiting toxicity. Pathologic diagnosis was centrally reviewed, distinguishing malignant SFT (M-SFT) and high-grade/dedifferentiated SFT (HG/D-SFT) subtypes. The primary end-point was the overall response rate (ORR) by Choi criteria (Choi). Secondary end-points were response by Response Evaluation Criteria in Solid Tumours (RECIST), progression-free survival (PFS) and overall survival (OS). RESULTS: From April 2015 and October 2017, 17 eligible patients entered the study (metastatic: 17; SFT subtype: 13 M-SFT, 4 HG/D-SFT; prior treatment: 9 antiangiogenics, 5 cytotoxics). All patients were evaluable for response. The best Choi response was seven partial response (PR) (ORR, 41.2%), six stable disease (SD) and four progressions. Choi-ORR was 54% (7/13) when only M-SFTs were considered. Four of seven responsive patients were pretreated with pazopanib. No responses were detected in HG/D-SFT. Best RECIST response was one PR (5.9%), 14 SD and two progressions. Toxicity was as expected. Median Choi-PFS was 5.1 (interquartile range [IQR]: 2.5-14.8) months. Median Choi-PFS was 14.8 (IQR: 5.1-18.0) and 2.8 (IQR: 2.0-5.9) months for patients responsive and non-responsive by Choi, respectively (p = 0.0416). At a 14.4-month median follow-up, median OS was 25.3 months. CONCLUSION: This study showed that axitinib is active in progressive advanced SFT. One-half of patients carrying the malignant variant of the disease responded, with a >12-month median progression arrest. Responses were better detected with Choi and seen even in patients resistant to other antiangiogenics. Tolerability was good.

Pazopanib for treatment of advanced malignant and dedifferentiated solitary fibrous tumour: a multicentre, single-arm, phase 2 trial.

BACKGROUND: A solitary fibrous tumour is a rare soft-tissue tumour with three clinicopathological variants: typical, malignant, and dedifferentiated. Preclinical experiments and retrospective studies have shown different sensitivities of solitary fibrous tumour to chemotherapy and antiangiogenics. We therefore designed a trial to assess the activity of pazopanib in a cohort of patients with malignant or dedifferentiated solitary fibrous tumour. The clinical and translational results are presented here. METHODS: In this single-arm, phase 2 trial, adult patients (aged ≥ 18 years) with histologically confirmed metastatic or unresectable malignant or dedifferentiated solitary fibrous tumour at any location, who had progressed (by RECIST and Choi criteria) in the previous 6 months and had an ECOG performance status of 0-2, were enrolled at 16 third-level hospitals with expertise in sarcoma care in Spain, Italy, and France. Patients received pazopanib 800 mg once daily, taken orally without food, at least 1 h before or 2 h after a meal, until progression or intolerance. The primary endpoint of the study was overall response measured by Choi criteria in the subset of the intention-to-treat population (patients who received at least 1 month of treatment with at least one radiological assessment). All patients who received at least one dose of the study drug were included in the safety analyses. This study is registered with ClinicalTrials.gov, number NCT02066285, and with the European Clinical Trials Database, EudraCT number 2013-005456-15. FINDINGS: From June 26, 2014, to Nov 24, 2016, of 40 patients assessed, 36 were enrolled (34 with malignant solitary fibrous tumour and two with dedifferentiated solitary fibrous tumour). Median follow-up was 27 months (IQR 16-31). Based on central radiology review, 18 (51%) of 35 evaluable patients had partial responses, nine (26%) had stable disease, and eight (23%) had progressive disease according to Choi criteria. Further enrolment of patients with dedifferentiated solitary fibrous tumour was stopped after detection of early and fast progressions in a planned interim analysis. 51% (95% CI 34-69) of 35 patients achieved an overall response according to Choi criteria. Ten (29%) of 35 patients died. There were no deaths related to adverse events and the most frequent grade 3 or higher adverse events were hypertension (11 [31%] of 36 patients), neutropenia (four [11%]), increased concentrations of alanine aminotransferase (four [11%]), and increased concentrations of bilirubin (three [8%]). INTERPRETATION: To our knowledge, this is the first trial of pazopanib for treatment of malignant solitary fibrous tumour showing activity in this patient group. The manageable toxicity profile and the activity shown by pazopanib suggests that this drug could be an option for systemic treatment of advanced malignant solitary fibrous tumour, and provides a benchmark for future trials. FUNDING: Spanish Group for Research on Sarcomas (GEIS), Italian Sarcoma Group (ISG), French Sarcoma Group (FSG), GlaxoSmithKline, and Novartis.

Efficacy and Safety of Pazopanib for Recurrent or Metastatic Solitary Fibrous Tumor.

OBJECTIVE: To investigate the efficacy and safety of pazopanib for recurrent or metastatic solitary fibrous tumor (SFT) in first- and second-line settings. METHODS: Patients histologically diagnosed with SFT at our hospital who received pazopanib monotherapy for inoperable disease between January 2013 and November 2016 were eligible. We retrospectively investigated treatment outcomes according to the treatment lines and assessed adverse events. RESULTS: Nine patients were eligible. The median age was 67 years (range 42-81), and 6 patients (66.7%) were male. Four patients (50%) received pazopanib as second-line treatment. According to the RECIST and Choi criteria, the respective response rates were 0 and 50%, while the respective disease control rates were 88.9 and 75%. The median progression-free survival (PFS) was 6.2 months (95% confidence interval 3.2-8.8). Treatment line and high frequency of mitosis were not predictive of PFS (p = 0.67, 0.92). Two patients (22.2%) experienced elevated liver enzymes of grade 3 or higher. CONCLUSION: Pazopanib is an effective treatment option for recurrent or metastatic SFT in first- and second-line settings. Liver injury is a major adverse event and adequate treatment withdrawal and dose reduction should be considered when necessary.

Pazopanib efficacy in recurrent central nervous system hemangiopericytomas.

INTRODUCTION: There is currently no treatment for solitary fibrous tumors/hemangiopericytomas (SFT/H) of the central nervous system recurring after multiple surgeries and radiotherapies. The NAB2-STAT6 gene fusion is the hallmark of these tumors, and upregulates Early Growth Factor, activating several growth pathways. METHODS: We treated two patients presenting pluri-recurrent meningeal SFT/H with Pazopanib, a broad-spectrum tyrosine kinase inhibitor. We analyzed the exome and RNA sequencing data of one of them and, in addition to another meningeal SFT/H, compared it to the transcriptomic profiling of 5 systemic SFT/H. RESULTS: A dramatic clinical and radiological response was observed in both cases, respectively 84 and 43% decrease after 3 months. As a comparison, Pazopanib has only a stabilizing effect in systemic SFT/H. Indeed, central nervous system SFT/H show overexpression of different tyrosine kinases targeted by Pazopanib. CONCLUSIONS: Two consecutive patients with untreatable central nervous system SFT/H showed a spectacular partial response to Pazopanib, an unprecedented result in SFT/H. This result could be explained by differences in expression profiles and calls for a confirmation in a larger cohort of patients.

Late Onset of Non-islet Cell Tumor Hypoglycemia Managed via Multidisciplinary Treatment in a Patient with a Solitary Fibrous Tumor.

Solitary fibrous tumor (SFT) is a rare subtype of soft tissue sarcoma (STS). We herein describe a case of late onset of non-islet cell tumor hypoglycemia (NICTH) that was managed via multidisciplinary treatment in a patient with SFT. A 67-year-old man previously diagnosed with SFT 4 years prior to this presentation and treated with several rounds of surgery, presented with massive tumors. Eighteen months following his prescribed chemotherapy, the patient developed hypoglycemia. He was diagnosed with NICTH, after confirming the presence of high molecular weight insulin-like growth factor-2. This case suggests that paraneoplastic syndrome can occur even in cases of rare cancers, such as STS.

Treatment patterns and clinical outcomes with pazopanib in patients with advanced soft tissue sarcomas in a compassionate use setting: results of the SPIRE study.

BACKGROUND: A named patient program (NPP) was designed to provide patients with advanced soft-tissue sarcoma (aSTS) access to pazopanib, a multitargeted tyrosine kinase inhibitor. The SPIRE study was a retrospective chart review of participating patients. PATIENTS AND METHODS: Eligibility criteria for the NPP and SPIRE mirrored those of the pivotal phase-III study, PALETTE, which compared pazopanib with placebo in patients ≥18 years with aSTS and whose disease had progressed during or following prior chemotherapy or were otherwise unsuitable for chemotherapy. Outcomes of interest included treatment patterns, treatment duration, relative dose intensity, progression-free survival (PFS), overall survival (OS), clinical benefit rate, adverse events (AEs) and reasons for treatment discontinuation. RESULTS: A total of 211 patients were enrolled (median age 56 years; 60% female). Most patients received pazopanib in second- and third-line therapy (28.0% and 28.4%, respectively), followed by fourth line (19.0%) and ≥ fifth line (18.5%). The median duration of pazopanib treatment was 3.1 months (95% CI: 2.8-3.8), with a mean daily dose of 715 mg equating to 92% of recommended dose. Median OS was 11.1 months and clinical benefit rate was 46%. There was evidence of some clinical benefit across most histological subtypes. At study end, 40% of patients were alive and of these, 18% remained on pazopanib. Thirteen percent (13%) of patients discontinued pazopanib due to AEs. CONCLUSIONS: The SPIRE study demonstrated activity of pazopanib in heavily pretreated aSTS patients in a compassionate use setting. No new safety concerns were noted. Reassuringly, the relative dose intensity of pazopanib was 92%.

Patient-derived solitary fibrous tumour xenografts predict high sensitivity to doxorubicin/dacarbazine combination confirmed in the clinic and highlight the potential effectiveness of trabectedin or eribulin against this tumour.

BACKGROUND: Preclinical models that mimic pathological and molecular features of solitary fibrous tumour (SFT) represent an important tool to select effective regimes and novel compounds to be tested in the clinic. This study was aimed at developing two preclinical models of SFT, assessing their predictive value in the clinic and selecting potential novel effective treatments. MATERIAL AND METHODS: Two dedifferentiated-SFT (D-SFT) models obtained from patients' biopsies were grown in immunodeficient mice. The antitumour activity on these models of doxorubicin, dacarbazine (DTIC), ifosfamide (monotherapy or combination), trabectedin and eribulin was tested. Twelve SFT patients were treated with doxorubicin and DTIC. Response by RECIST, progression-free survival and overall survival were retrospectively evaluated, distinguishing malignant-SFT (M-SFT) and D-SFT. RESULTS: Two D-SFT patient-derived xenografts (PDXs) that represent the first available preclinical in vivo models of SFT were developed and characterised. Doxorubicin/DTIC, DTIC/ifosfamide, doxorubicin/ifosfamide combinations consistently induced better antitumour activity than the single-agents. Particularly, doxorubicin/DTIC combination caused a max tumour volume inhibition >80% in both models. Doxorubicin/DTIC combo showed activity also in the case-series. Best RECIST responses were: 6 responses (M-SFT = 2 of 7, D-SFT = 4 of 5), 1 stable disease, 5 progressions, with a 6-month median progression-free survival (M-SFT = 6, D-SFT = 10 months). The PDXs were very sensitive to trabectedin and eribulin. CONCLUSION: Doxorubicin plus DTIC combination was effective in our two D-SFT mice models and appeared to be active also in the clinic, especially in high-grade D-SFT patients. Among additional drugs tested in the PDXs, trabectedin and eribulin were highly effective, providing a rational to test these drugs in D-SFT patients.

Clinical behavior of solitary fibrous tumor: a retrospective review of 30 patients

Background. Solitary fibrous tumors (SFTs) are a rare type of soft tissue sarcoma of unpredictable clinical behavior. Some clinicopathologic characteristics have also been related to patient outcome. Methods. This study is a retrospective review of 30 patients. We analyzed the clinical course and pathological factors to predict recurrence. Results. The mean age was 55.9 years. Forty-five percent were located in the thoracic region. The mean tumor size was 10 cm (max24). Thirty-three percent had a relapse and 20 % have died. Median time to relapse was 7.18 (1-13) years. Median overall survival (OS) was 15.5 years (0-32). On histopathologic analysis, 6 % percent had >4 mitoses, 23 % had necroses, and 36 % had atypia/pleomorphism. Forty-three percent had tumor size >10 cm. Forty-six percent had at least one characteristic of malignancy. None of this data could predict clinical behavior by itself. Conclusions. SFT can be an aggressive disease and relapses can occur several years from diagnosis. We did not find any clinicopathologic factors that could predict the tumor behavior accurately. Nevertheless, it should be consider that we included different tumor locations and the sample size is small (AU)

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Phase 2 study of dasatinib in patients with alveolar soft part sarcoma, chondrosarcoma, chordoma, epithelioid sarcoma, or solitary fibrous tumor.

BACKGROUND: Alveolar soft part sarcoma (ASPS), chondrosarcoma (CS), chordoma, epithelioid sarcoma, and solitary fibrous tumor (SFT) are malignant tumors that are relatively resistant to chemotherapy and for which more effective drug therapy is needed. METHODS: The 5 listed subtypes were enrolled into a single indolent sarcoma cohort in a phase 2 study of dasatinib using a Bayesian continuous monitoring rule for enrollment. The primary objective was to estimate the 6-month progression-free survival (PFS) rate according to the Choi criteria with a target of ≥50%. Cross-sectional imaging was performed before the start of treatment, every 2 months for 6 months, and then every 3 months during treatment. The 2- and 5-year survival rates were determined. RESULTS: One hundred sixteen patients were enrolled within 45 months, and 109 began treatment with dasatinib. The 6-month PFS rate and the median PFS were 48% and 5.8 months, respectively. The PFS rate at 6 months was highest with ASPS (62%) and lowest with SFT (30%). More than 10% of the patients with ASPS, CS, or chordoma had stable disease for more than 1 year. Collectively, for all 5 subtypes, the 2- and 5-year overall survival rates were 44% and 13%, respectively. An objective response was observed in 18% of the patients with CS or chordoma. CONCLUSIONS: Dasatinib failed to achieve control of sarcoma growth for at least 6 months in more than 50% of the patients in this trial according to the Choi tumor response criteria. An objective tumor response and prolonged stable disease was observed in >10% of patients with CS or chordoma. Cancer 2017;90-97. © 2016 American Cancer Society.

Sunitinib-induced morpho-functional changes and drug effectiveness in malignant solitary fibrous tumours.

Sunitinib improves the outcomes of patients with solitary fibrous tumours (SFTs). The aim of this study was to investigate and contextualise sunitinib-induced morpho-functional changes in order to gain insights into the drug's mechanism of action.To this end, four surgical specimens obtained from two sunitinib-responsive patients with malignant SFT, and one primary cell culture obtained from fresh tumoral tissue and its stabilised cell line, were studied by means of immunohistochemistry, bright field in situ hybridisation, immunofluorescence/confocal microscopy, and biochemistry.The post-sunitinib surgical samples were characterised by two biologically relevant morpho-functional changes: clear areas and necrotic foci. The first were associated with the attenuation/loss of PDGFRB expression and decreased mTOR signalling, and corresponded to a pathological response. The second were associated with the over-expression of PDGFRB and VEGFA, strong mTOR signalling activation, and the appearance of HIF1α expression, hallmarks of pathological progression. The analysis clearly showed that sunitinib reduces the vascular supply network and inhibits tumoral cells. It also either induces autophagy, thus favouring drug response, or impairs autophagy as a result of lysosome sequestration, thus favouring disease progression. These distinct autophagic events were associated with different myeloid immune contextures. Finally, we also found that PDGFRB is one of the components of a complex that includes Beclin 1 and VPS34.The results of these tissue-based analyses provide new insights into sunitinib's mechanism of action in SFT patients.

Efficacy of trabectedin in malignant solitary fibrous tumors: a retrospective analysis from the French Sarcoma Group.

BACKGROUND: Advanced malignant solitary fibrous tumors (SFTs) are rare soft-tissue sarcomas with a poor prognosis. Several treatment options have been reported, but with uncertain rates of efficacy. Our aim is to describe the activity of trabectedin in a retrospective, multi-center French series of patients with SFTs. METHODS: Patients were mainly identified through the French RetrospectYon database and were treated between January 2008 and May 2013. Trabectedin was administered at an initial dose of 1.5 mg/m(2), q3 weeks. The best tumor response was assessed according to the Response Evaluation Criteria In Solid Tumors 1.1. The Kaplan-Meier method was used to estimate median progression-free survival (PFS) and overall survival (OS). The growth-modulation index (GMI) was defined as the ratio between the time to progression with trabectedin (TTPn) and the TTP with the immediately prior line of treatment (TTPn-1). RESULTS: Eleven patients treated with trabectedin for advanced SFT were identified. Trabectedin had been used as second-line treatment in 8 patients (72.7 %) and as at least third-line therapy in a further 3 (27.3 %). The best RECIST response was a partial response (PR) in one patient (9.1 %) and stable disease (SD) in eight patients (72.7 %). Disease-control rate (DCR = PR + SD) was 81.8 %. After a median follow-up of 29.2 months, the median PFS was 11.6 months (95 % CI = 2.0; 15.2 months) and the median OS was 22.3 months (95 % CI = 9.1 months; not reached). The median GMI was 1.49 (range: 0.11-4.12). CONCLUSION: Trabectedin is a very promising treatment for advanced SFTs. Further investigations are needed.

Preclinical and clinical evidence of activity of pazopanib in solitary fibrous tumour.

BACKGROUND: To explore the activity of pazopanib in solitary fibrous tumour (SFT). PATIENTS AND METHODS: In a preclinical study, we compared the activity of pazopanib, sorafenib, sunitinib, regorafenib, axitinib and bevacizumab in a dedifferentiated-SFT (DSFT) xenotransplanted into Severe Combined Immunodeficiency (SCID) mice. Antiangiogenics were administered at their reported optimal doses when mean tumour volume (TV) was 80 mm(3). Drug activity was assessed as TV inhibition percentage (TVI%). From May 2012, six consecutive patients with advanced SFT received pazopanib, on a national name-based programme. In one case sunitinib was administered after pazopanib failure. RESULTS: In the xenograft model, pazopanib showed the lowest antitumour activity (21%TVI), while regorafenib was the most active (95%TVI). Sorafenib, bevacizumab, sunitinib were markedly active (78/70/65%TVI). Axitinib was marginally active (51%TVI). In the retrospective case-series, three patients carried malignant-SFT (MSFT), three DSFT. Best Response Evaluation Criteria in Solid Tumour (RECIST) responses were: three stable disease (SD), all MSFT, three progressive disease (PD), all DSFT, corresponding to one partial response (PR), two SD, three PD by Choi criteria. Median-progression-free survival was 3 months (range 1-15). In one patient, sunitinib was started after pazopanib failure, with a response. CONCLUSIONS: In dedifferentiated-SFT xenograft pazopanib induced a marginal antitumour activity, while regorafenib appeared the most active and promising agent. When administered in patients, pazopanib showed a modest activity in terms of tumour growth stabilisation, observed only in non-dedifferentiated cases.