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

BACKGROUND

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

METHODS

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

FINDINGS

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

INTERPRETATION

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

FUNDING

Adaptimmune.

Selinexor in Advanced, Metastatic Dedifferentiated Liposarcoma: A Multinational, Randomized, Double-Blind, Placebo-Controlled Trial

PURPOSE

Antitumor activity in preclinical models and a phase I study of patients with dedifferentiated liposarcoma (DD-LPS) was observed with selinexor. We evaluated the clinical benefit of selinexor in patients with previously treated DD-LPS whose sarcoma progressed on approved agents.

METHODS

SEAL was a phase II-III, multicenter, randomized, double-blind, placebo-controlled study. Patients age 12 years or older with advanced DD-LPS who had received two-five lines of therapy were randomly assigned (2:1) to selinexor (60 mg) or placebo twice weekly in 6-week cycles (crossover permitted). The primary end point was progression-free survival (PFS). Patients who received at least one dose of study treatment were included for safety analysis (ClinicalTrials.gov identifier: NCT02606461).

RESULTS

Two hundred eighty-five patients were enrolled (selinexor, n = 188; placebo, n = 97). PFS was significantly longer with selinexor versus placebo: hazard ratio (HR) 0.70 (95% CI, 0.52 to 0.95; one-sided P = .011; medians 2.8 v 2.1 months), as was time to next treatment: HR 0.50 (95% CI, 0.37 to 0.66; one-sided P < .0001; medians 5.8 v 3.2 months). With crossover, no difference was observed in overall survival. The most common treatment-emergent adverse events of any grade versus grade 3 or 4 with selinexor were nausea (151 [80.7%] v 11 [5.9]), decreased appetite (113 [60.4%] v 14 [7.5%]), and fatigue (96 [51.3%] v 12 [6.4%]). Four (2.1%) and three (3.1%) patients died in the selinexor and placebo arms, respectively. Exploratory RNA sequencing analysis identified that the absence of CALB1 expression was associated with longer PFS with selinexor compared with placebo (median 6.9 v 2.2 months; HR, 0.19; P = .001).

CONCLUSION

Patients with advanced, refractory DD-LPS showed improved PFS and time to next treatment with selinexor compared with placebo. Supportive care and dose reductions mitigated side effects of selinexor. Prospective validation of CALB1 expression as a predictive biomarker for selinexor in DD-LPS is warranted.

Prognostic value of EZH2 expression for immunotherapy-based schemes in advanced soft-tissue sarcoma: A translational research from Spanish Group of Research on Sarcoma (GEIS)

11549

Background: Immunotherapy-based treatments had shown to be active in several solid tumors, including in selected subtypes of sarcomas. IMMUNOSARC (NCT03277924) is a phase Ib/II trial [from Spanish (GEIS) and Italian (ISG) sarcoma groups], that tested the combination of nivolumab (anti-PD-1 inhibitor) plus sunitinib (anti-angiogenic agent) in advanced sarcomas. Among the 65 soft-tissue sarcoma (STS) patients (pts) enrolled, 48% were free of progression at 6 months, meeting the trial’s primary endpoint. EZH2 is the catalytic subunit of the Polycomb Repressive Complex 2 and it has been described to play an important role in the transcriptional repression of genes involved in T-cell migration and T-cell-mediated anti-tumor activity. The aim of this study was to explore the value of EZH2 gene expression as potential prognostic biomarker of the activity of immunotherapy-based schemes. Methods: The expression of EZH2 was evaluated in 64 paraffin tumor blocks, by direct transcriptomics, using HTG EdgeSeq Oncology Biomarkers Panel (HTG Molecular Diagnostics, Inc.; Tucson, AZ, USA). Data was normalized with DESeq2 and the cut-off of EZH2 expression was calculated with MAXSTAT R package. Gene expression was correlated with progression-free survival (PFS) by RECIST, overall survival (OS) and clinical benefit (patients with response or stable disease vs patients with progressive disease as best response). Results: Among the 64 pts analyzed, 52 (81%) showed overexpression of EZH2, considering a cut-off of 570.15 read counts. Undifferentiated pleomorphic sarcoma (UPS) and epithelioid sarcoma were the subtypes with higher expression of EZH2 with a median of read counts of 1888.04 (n = 10) and 1261.79 (n = 7), respectively. The lowest expressions were observed in extraskeletal myxoid chondrosarcoma (ECM) and alveolar soft-part sarcoma (ASPS) with a median of read counts of 461.42 (n = 4) and 680.84 (n = 7), respectively. Low expression of EZH2 was associated with better PFS (16.8 months vs. 3.9 months; p = 0.001) and better OS (NR vs. 20.0 months; p = 0.006). Moreover, low expression of EZH2 was also significantly associated with a clinical benefit of the patients treated with nivolumab plus sunitinib [relative risk (RR): 13; 95% CI: 3.0-56.9; p = < 0.001). Conclusions: Low expression of EZH2 was associated with better outcome in advanced STS patients treated with immunotherapy-based schemes. These results might support the rationale for the combination of EZH2 inhibitors with immune-modulating agents for future studies.

Identification of response stratification factors from pooled efficacy analyses of afamitresgene autoleucel (“Afami-cel” [Formerly ADP-A2M4]) in metastatic synovial sarcoma and myxoid/round cell liposarcoma phase 1 and phase 2 trials

11562

Background: Afami-cel is an autologous, HLA-A*02-restricted, specific peptide enhanced affinity receptor, T-cell therapy engineered to target MAGE-A4+ solid tumors. The pivotal, 2-cohort, single-arm, Phase 2, SPEARHEAD-1 trial (NCT04044768) with afami-cel met its primary endpoint based on Cohort 1 data. As of September 1, 2021, in 47 patients (pts) with metastatic synovial sarcoma (SyS) or myxoid/round cell liposarcoma (MRCLS), the overall response rate (ORR) per independent review was 34% with encouraging durability (Van Tine, et al. Paper 30: CTOS 2021; Virtual). To identify potential stratification factors for response and assess whether response is a proxy for progression-free survival (PFS), we present pooled analyses using data from the prior Phase 1 trial (NCT03132922) and Cohort 1 of the SPEARHEAD-1 trial. Methods: Eligible pts (16–75 years) were HLA-A*02+ with MAGE-A4+ tumors. Pts received afami-cel after lymphodepleting chemotherapy. The pooled analyses evaluated ORR per RECIST v1.1 by investigator review, stratified by 7 factors, and safety. Results: In the pooled data, 69 pts received afami-cel (2.12–9.99×109 transduced T-cells) and were evaluable for response (Phase 1, n = 18; Phase 2, n = 51); all expressed one eligible HLA-A*02 allele. Median (range) for: age was 42 years (19–76), number of prior lines of therapy was 2 (1–12), and tumor MAGE-A4 H-score was 230 (60–300). Median (range) H-score was higher in SyS (256 [60–300]) than in MRCLS (180 [112–230]). The pooled investigator-assessed ORR was 36.2% (40.7% in SyS; 10.0% in MRCLS). Responses occurred across a wide MAGE-A4 H-score range (134–300). Median (range) duration of response was 52 weeks (8.29–75.14). Response rate was higher in the 59 pts with SyS: with ≤2 vs ≥3 prior lines of therapy (55.2% vs 26.7%), baseline target lesion sum of longest diameters <10cm vs ≥10cm (53.1% vs 25.9%), MAGE-A4 H-score ≥200 vs <200 (46.3% vs 27.8%), without vs with bridging therapy (48.6% vs 29.2%), who were female vs male (46.4% vs 35.5%), aged ≥40 vs <40 years (45.7% vs 33.3%), and from North America vs Europe (42.6% vs 33.3%). In responders vs non-responders with SyS, respectively, median PFS was 58.3 vs 11. 0 weeks (log-rank p-value <0.0001); the probability of being progression-free at 24 weeks was 0.8 vs 0.2. The pooled benefit:risk profile of afami-cel was similar to that in the SPEARHEAD-1 trial (Van Tine, et al. Paper 30: CTOS 2021; Virtual.). Conclusions: We show that baseline tumor burden, prior systemic treatment history, and MAGE-A4 tumor expression levels are potential factors associated with response to afami-cel, although their true predictive value for response status awaits confirmation. Our findings will inform the ongoing clinical development of afami-cel in sarcoma, especially for prognostic studies with PFS or overall survival endpoints. Clinical trial information: NCT04044768, NCT03132922.

SPEARHEAD-1: A phase 2 trial of afamitresgene autoleucel (Formerly ADP-A2M4) in patients with advanced synovial sarcoma or myxoid/round cell liposarcoma

11504

Background: This phase 2, open-label trial (SPEARHEAD-1; NCT04044768) is designed to evaluate the efficacy, safety, and tolerability of afamitresgene autoleucel in 45 patients (pts) with advanced/metastatic synovial sarcoma or Myxoid/Round Cell Liposarcoma (MRCLS). Methods: Eligible pts are HLA-A*02 positive with MAGE-A4-expressing tumors. Pts undergo leukapheresis for collection of autologous T-cells for processing and manufacture into afamitresgene autoleucel cells. Pts were treated with afamitresgene autoleucel doses between 1–10 × 109 transduced T-cells after receiving lymphodepleting chemotherapy. The primary endpoint is overall response rate per RECIST v1.1 by independent review. An independent Data Safety Monitoring Board reviews ongoing safety and benefit: risk during the interventional phase. Results: As of Feb 4, 2021, 32 pts received afamitresgene autoleucel. Of these pts, 59% were male, 87.5% had synovial sarcoma, the median age was 43 yrs (range: 24–73), and they had a median of 3 prior systemic lines of therapy. The MAGE-A4 antigen expression level (histoscore) ranged from 112–300, and the transduced cell dose ranged from 2.7–9.9 x 109. At the data cutoff, 25 pts were evaluable for preliminary efficacy (23 with synovial sarcoma and 2 with MRCLS) and 7 pts (5 with synovial sarcoma and 2 with MRCLS) had insufficient follow-up (<8 weeks follow-up and/or awaiting first scan). Of the 25 evaluable pts, the investigator-assessed responses were: complete response (2 pts), partial response (8 pts), stable disease (11 pts), and progressive disease (4 pts). All responses were confirmed. Nine of the 10 responders had ongoing response at the data cutoff and 3 responders had MAGE-A4 antigen histoscores <200. The most common AEs of any grade (>30% pts) were neutropenia, lymphopenia, nausea, cytokine release syndrome, leukopenia, fatigue, pyrexia, and anemia. Cytokine release syndrome of any grade occurred in 19/32 pts; 95% of those events were ≤Grade 2. No immune effector cell-associated neurotoxicity syndrome (ICANS) has been reported to date. Cytopenia (≥G3) at 4 wks post-infusion was observed in 6 pts (anemia 3 pts, neutropenia 2 pts, and thrombocytopenia 1 pt). Conclusion: These preliminary data demonstrate afamitresgene autoleucel is efficacious and well tolerated in heavily pre-treated pts. Objective responses are reported across a wide range of MAGE-A4 antigen levels and deep responses have been observed. Initial durability data is encouraging. Preliminary response data in SPEARHEAD-1 is comparable to the findings of the prior Phase 1 trial [1]. To date, the safety profile of afamitresgene autoleucel has been favorable, with mainly low-grade cytokine release syndrome and tolerable/reversible hematologic toxicities. [1]. Van Tine BA, et al. CTOS; November 18-21, 2020; Virtual. Clinical trial information: NCT04044768.

Results of the second interim assessment of rEECur, an international randomized controlled trial of chemotherapy for the treatment of recurrent and primary refractory Ewing sarcoma (RR-ES)

11502

Background: Five-year survival of RR-ES is about 15%. Several chemotherapy regimens are used, but without robust evidence. rEECur, the first randomised controlled trial in this setting, is defining a standard of care, balancing efficacy and toxicity. Methods: Patients aged 4 to 50 with RR-ES and fit to receive chemotherapy were randomised between topotecan & cyclophosphamide (TC), irinotecan & temolozomide (IT), gemcitabine & docetaxel (GD) or high-dose ifosfamide (IFOS). Primary outcome measure was objective response (OR) after 4 cycles by RECIST 1.1. Secondary outcomes included PFS, OS and toxicity. A probability-based Bayesian approach was used with multiple pairwise comparisons. At the first interim analysis patients allocated to GD had worse OR and PFS than the other arms and accrual to the GD arm was halted. The second interim assessment was planned to determine which arm should be closed when at least 75 evaluable patients had been recruited to the remaining arms and evaluated for the primary outcome measure. Results: 366 patients (87% RECIST-evaluable), recruited between 18/12/14 and 17/12/19, were randomised to TC (n=124), IT (118), GD (72) and IFOS (53). Median age was 20 years (range 4-49). Patients had: refractory disease (19%), first recurrence (66%), > first recurrence (14%). Initial disease site was bone in (66%). Sites of progression were: primary site only (16%) pleuropulmonary only (32%), other metastatic (52%). At median follow up of 9.2 months, outcome in the IT arm was: response rate 20%, median PFS 4.7 months (95% CI: 3.4 to 5.7), median OS 13.9 months (95% CI: 10.6 to 18.1). The table shows, for each pairwise comparison of IT with the other open arms (randomly labelled A and B to maintain blinding), the probabilities that OR, PFS and OS were better for X than for each other arm (RR = risk ratio, HR = hazard ratio). For OR, PFS and OS, all comparisons favoured arms A and B. The main grade 3/4 adverse events (% patients with an event) for IT (left hand values) compared with A and B pooled were: vomiting (6% v 1%), nausea (6% v 0%), diarrhoea (17% v 0%), fatigue (3% v 1%) and febrile neutropenia (3% v 24%). Conclusions: The first randomised trial in RR-ES has shown that IT, used as a control arm in planned and ongoing randomised phase II studies in RR-ES, is less effective than A and B in achieving tumour shrinkage or prolonging PFS and OS. The remaining two arms are continuing to recruit patients. Clinical trial information: ISRCTN36453794 . [Table: see text]

Trabectedin and radiotherapy in soft-tissue sarcoma (TRASTS) study: An international, prospective, phase II trial in localized myxoid liposarcoma—A collaborative Spanish (GEIS), Italian (ISG) and French (FSG) group study

11514

Background: Myxoid liposarcoma (ML) exhibits especial sensitivity to trabectedin (T). In prospective series, T showed responses in 44% of patients (pts) with ML. ML is also sensitive to radiation therapy (RT) and preclinical data suggested radiosensitizing properties of T. Preoperative short-course of T with concurrent low-dose RT was conducted in a multicenter, European, phase I/II trial. We present here the data from the phase II part in pts with centralized diagnosis of locally advanced, resectable ML. Methods: Pts received 3 cycles (C) of T in combination with RT (45 Gy) in 25 fractions (1.8Gy/fraction). The phase I part of the study had the classic 3+3 design. Dose Levels for T were: -1 (1.1 mg/m2), 1 (1.3 mg/m2) and 2 (1.5 mg/m2) Results were already reported (EClincalMedicine 2019;9:35-43) and the dose selected for the phase 2 part was 1.5 mg/m2. RECIST responses were evaluated preoperatively at week 10. Surgical specimens were processed for histologic changes and residual tumor. Results: From July 2016 to September 2019, 47 pts (M/F 31/16) with median age 43y (18-77) and median tumor size 11 cm (3-25 cm), 20 low and 24 high grade (3 not available) were enrolled in the phase II part of the study. The major grade 3/4 toxicities were neutropenia (21.3%), ALT (14.9%), GGT (8.5%) and AST (8.5%) elevation. There were no deaths due to toxicity. 43/47 patients received the planned 3 pre-operative T cycles. All pts completed RT. 1 patient started RT before the first cycle of T and was excluded from the analysis. All pts were evaluable for response: 14 achieved PR (30%), 32 SD (70%). All pts underwent surgery (37 [86%] R0/ 5 [12%] R1/ 1 [2%] R2/ 3 not available). Median viable residual tumor was 10% (0-90) with 23/43 pts (53%) with ≤ 10% viable remaining tumor. Of them 6/43 (14%) had complete responses. At a median FU of 18 months (3-41) one pt developed local recurrence and 2 distant metastases. No deaths were observed. The corresponding 2-yr disease-free survival and overall survival were 97% (95% confidence interval 95-100) and 100%. Conclusions: T in combination with RT was feasible and well tolerated in the preoperative setting. The activity of the combination compares favorably with the administration of T/RT alone. This regimen could potentially become an alternative to anthracycline+ifosfamide concurrent to RT in high risk localized ML. Clinical trial information: NCT02275286 .

Immune-checkpoint genes as predictive biomarkers of trabectedin in advanced soft-tissue sarcoma (STS): A Spanish Group for Research on Sarcomas (GEIS) translational study

11546

Background: Despite several second-line options are accessible for the treatment of advanced STS, there is a lack of predictive biomarkers available to support the rational selection of these drugs. Trabectedin specifically targets mononuclear cell lineage (macrophages and monocytes) that ultimately could inhibit tumor angiogenesis. Moreover, trabectedin seems to induce the expression of immune-checkpoint proteins (e.g. PD-L1); however, the predictive value of these factors remains unknown. We present the analyses of immune-checkpoint genes ( CD274, CD86, CTLA4, HAVCR2, LAG3 and PDCD1) and CD163, CD4, CD68 and CD8A expression as potential predictive factors of response to trabectedin in a subset of STS patients of the GEIS registry. Methods: Selection criteria included patients with STS, pretreated with at least 2 lines in the advanced setting (one line being trabectedin), with paraffin block available and ethic committee’s approval. Direct transcriptomics was performed using HTG Molecular Oncology Biomarker Pathway panel (HTG Molecular Diagnostics, Inc.; Tucson, AZ, USA), following manufacturers’ instructions. Data analyses were performed taking into account the median Log2 of expression of each gene and by correlating it with progression-free survival (PFS) for trabectedin, and overall survival measured from the starting date of trabectedin treatment (OS). Results: Among 387 registered patients, fitting with the inclusions criteria, 139 cases were used for gene expression analyses, as the discovery set. Patients had median age of 52 years, 54% were females and had a median follow-up from diagnosis of 44 months. High expression of CD274 (PD-L1) was significantly associated with better PFS of trabectedin (5.4 vs. 3.0 months; p= 0.006). Similar results were obtained with high expression of CTLA4 and LAG3: 6.0 vs 3.1 months; p = 0.005 and 5.4 vs 2.7 months; p = 0.042, respectively. Expression of CTLA4 and LAG3 showed no significant impact in OS; whereas CD274 high expression showed a trend towards better OS (17.9 vs 10.2 months; p = 0.077). Also, no significant correlation was achieved for CD163, CD4, CD68, CD8A, CD86 and HAVCR2; PDCD1 (PD-1) showed a trend towards better PFS of trabectedin, p = 0.114. Conclusions: The expression of selected immune-checkpoint genes exhibited a potential predictive value for trabectedin in advanced STS. Validation studies (at the transcriptional and protein level) are currently ongoing to confirm their potential predictive role.

IMMUNOSARC: a collaborative Spanish (GEIS) and Italian (ISG) sarcoma groups phase I/II trial of sunitinib and nivolumab in advanced soft tissue and bone sarcoma: Results from the phase II part, bone sarcoma cohort

11522

Background: Herein, we present the results of the cohort on advanced bone sarcoma patients of the phase II part of the IMMUNOSARC study (NCT03277924), a European multicentre phase I-II trial aimed at investigating the activity of the combination of sunitinib (SU) and nivolumab (NI) in selected advanced sarcoma subtypes. Methods: Adult, pre-treated, progressing patients, ECOG 0-1, with a diagnosis of osteosarcoma, high-grade bone sarcoma, Ewing sarcoma, chondrosarcoma or dedifferentiated chondrosarcoma were eligible. SU 37.5 mg/day as induction was given days 1-14 and then reduced to 25mg/day continuously. NI was administered at 3 mg/Kg every 2 weeks from week 3. SU-NI was maintained up to progression or intolerance. Primary end-point was progression-free survival rate (PFSR) at 6 months (H1: PFSR 6-months: 15%). Secondary end-points: overall survival (OS), objective response rate (ORR) by RECIST v 1.1 and toxicity. Results: From Nov 2017 to Dec 2018, 40 eligible patients were included: (M/F = 27/13), median age 47 years (range 21-74), ECOG 0 in 11 (27%) cases, 36 (90%) were metastatic, 4 (10%) locally advanced. Histology: 17 osteosarcomas (43%), 14 chondrosarcomas (35%) (4 dedifferentiated), 8 Ewing sarcomas (20%), 1 bone undifferentiated pleomorphic sarcoma (2%). PFSR at 6 months based on local evaluation was 32%. At a median FU of 12.5 months (2-26), median PFS was 3.7 months (95% IC 3.4-4) while median OS was 14.2 months (95%CI: 7.1-21.3). OS rate at 3 and 6 months were 87% and 73%, respectively. ORR by RECIST: 1 CR (2.5%) (1 patient with dedifferentiated chondrosarcoma, lasting 22 months and on going), 1 PR (2.5%) (1 patient with osteosarcoma, lasting 5.7 months), 22 SD (55%, lasting > 6 months in 45% of the cases) and 16 PD (40%). G3/5 toxicities are detailed in Table. Conclusions: The trial met its primary endpoint in the cohort of patients with advanced bone sarcoma, with > 30% of patients free from progression at 6 months. Pre-planned tumor microenvironment genomic, exploratory analysis on pre and post-treatment tumor samples is on going. Clinical trial information: NCT03277924 . [Table: see text]

Effect of concurrent proton pump inhibitors (PPI) use in patients (pts) treated with immune checkpoint inhibitors (ICI) for metastatic urothelial carcinoma (mUC)

500

Background: PPI are widely used in pts with cancer. PPI are associated with anti-inflammatory properties and direct effects on neutrophils and monocytes that might prevent inflammation. We investigate the role of PPI on outcomes of pt receiving ICI in mUC. Methods: Medical records from pts with mUC treated with ICI from May 2013 to May 2019 using a multi-institutional database was evaluated. Use of PPI was defined: 30 days prior, during the treatment and 30 days after the last dose of ICI. ORR were assessed according to RECIST v1.1. The X2 test was used to determine differences in rates. PFS and OS were estimated using Kaplan-Method and long rank test was used to assess differences between groups. All analyses were performed using SPSS v21. Results: Overall, 115 pts received therapy with ICI. Of these pts, 20 were not included due to the absence of information about PPI. Thus, 95 pts were included for the analysis. 50 (52.6%) pts received PPI. Median age was 68 years, 79 pts (83.2%) were male, 78 pts (82.1%) had ECOG PS 0-1, 20 pts (21.1%) had liver metastasis and 36 pts (37.9%) received ICI treatment as frontline therapy. ICI prescribed were atezolizumab (58.9%), pembrolizumab (17.9%), durvalumab (12.6%), nivolumab (6.3%) and durvalumab/tremelimumab (4.2%). Pts with no PPIs use had higher ORR (CR [8.9%] +PR [14.4%]) compared to those pt who use PPIs (CR [4.4%] + PR [8.9%]) (P=0.197). Median PFS was 10.05 mo (95% CI: 3.86-16.27) for non PPI users and 3.87 mo (95% CI:1.84-5.91) for PPI users (P=0.04). Median OS was 19.71 mo (95% IC:8.93-30.49) for non PPI users and 7.9 mo (4.4-11.45) for PPI users (P=0.072). Conclusions: We have observed shorter PFS and trend toward lower OS and ORR for PPI users. The real impact of PPI should be confirmed in prospective studies.

Translational study associated to a phase II study evaluating the activity of pazopanib in patients (pts) with advanced/metastatic liposarcoma (LPS): A joint Spanish Sarcoma Group (GEIS) and German Interdisciplinary Sarcoma Group (GISG) study

11067

Background: GEIS 30 was a phase II study showing moderate activity of pazopanib in well-differentiated/dedifferentiated LPS (cohort A:37 pts, Progression free Survival (PFS) at 12 weeks (w) 43.2%) and no activity in Myxoid/round cell LPS (cohort B: 15 pts, PFS at 12w 13.3%). The present study aims to identify tumor and plasma biomarkers that are differently expressed in long responders (LRs) PFS > 24 w. Methods: Serum samples and paraffin-blocks at diagnosis were collected for 28 pts in cohort A and 11 in B. A total of 13 pts were LRs. Serum samples were obtained at baseline, after 3 w of treatment and at progression. A panel of 15 cytokines and growth factors were evaluated using Luminex technology (Millipore). Paraffin-blocks were evaluated for microvessel density (MVD) by CD31 immunostaining and Image Pro-Plus 7.0 Image Analysis System (Media-Cybernetics). For RNA expression analysis, the Oncology Biomarker Panel with probes for 2559 transcripts was used (HTG Molecular Diagnostics). Results: Serum cytokines showed that expression of angiopoietin (AGO) and BMP9 decreases during treatment, whereas GCSF increases. In addition, AGO and BMP overexpression at baseline was associated with worse prognosis in arm A (p = 0.09) and B (p = 0.01) respectively. No differences between study arms and outcome were appreciated by MVD. Gene expression revealed differences in some immunomodulators: PDL-1 was correlated with serum cytokines VEGFD (p = 0.04) and LEPTIN (p = 0.02); and PD-1 with VEGFD (p = 0.04), LEPTIN (p = 0.02), VEGFA (p = 0.02) and ANGIO (p = 0.03). PD1, in addition,was overexpressed in LRs (p = 0.05). Interestingly, three groups were identified in cohort A according to gene expression: Cluster 1, characterized by short-responder patients with the shortest overall survival, whereas cluster 3 (40% LRs) and 2 (63.6% LRs) showed longer survival rates (14.3%, 45.5% and 30% respectively) (p = 0.001). Conclusions: Gene expression profiling unveils three WD/DD-LPS biotypes according to their response to pazopanib, which could be potentially used to select pts for treatment

Results of the first interim assessment of rEECur, an international randomized controlled trial of chemotherapy for the treatment of recurrent and primary refractory Ewing sarcoma

11007

Background: 5-year survival of RR-ES is about 15%. Several chemotherapy regimens are used, but without robust evidence. rEECur, the first randomised controlled trial in this setting, is defining a standard of care, balancing efficacy and toxicity. Methods: Patients aged 4 to 50 with RR-ES and fit to receive chemotherapy were randomised 2, 3 or 4 ways between topotecan & cyclophosphamide (TC), irinotecan & temolozomide (IT), gemcitabine & docetaxel (GD) or high-dose ifosfamide (IFOS). Primary outcome measure was objective response (OR) after 4 cycles by RECIST 1.1. Secondary outcomes included PFS, OS and toxicity. A probability-based Bayesian approach was used. The first interim assessment to determine which arm should be closed occurred when 50 evaluable patients had been recruited to 3 arms and evaluated for the primary outcome measure. Results: 242 patients (89% RECIST-evaluable) recruited between 18/12/14 and 21/06/18 were randomised to TC (n=75), IT (71), GD (66) and IFOS (30). Median age was 21 years (range 4 to 49). Patients had: refractory ES (20%), 1st recurrence (63%), >1st recurrence (17%); initial primary disease arose in bone in 60%; disease progression sites were primary site (17%), pleuropulmonary (29%) or other metastatic (54%). Median follow up was 11.3 months. Outcomes in the GD arm were: response rate 11.5% (95% CI: 4.4 to 23%), median PFS 3.0 months (95% CI: 1.6 to 8.0), median OS 13.7 months (95% CI: 10.1 to 23.9). The table shows, for each pairwise comparison of GD with the other arms (randomly labelled A, B, C to maintain blinding of open arms), the probabilities given the observed data that OR, PFS and OS were better for GD than for each other arm (RR: relative risk, HR: hazard ratio). For OR and PFS, all comparisons favoured the other arms. There were fewer grade 3/4 adverse events with GD than with the other arms pooled (58% v. 74%). Conclusions: rEECur has shown that GD is a less effective treatment than TC, IT or IFOS in reducing tumour burden or prolonging PFS in RR-ES. Recruitment continues to the remaining arms. Clinical trial information: ISRCTN36453794. [Table: see text]

Predictive role of FAS for trabectedin in second lines of advanced soft tissue sarcoma (ASTS): A Spanish group for research on sarcoma (GEIS) study

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Background: There are currently several second-line options for the treatment of ASTS as gemcitabine combinations, trabectedin, pazopanib, eribulin or olaratumab plus doxorubicin in cases where anthracyclins are still possible. There is an unmet need for predictive biomarkers which hinders the rational selection of the best sequence in second line. We already published the prognostic value of FAS in first line of ASTS while this study analyzes its predictive role in different second line schemes. Methods: Most relevant selection criteria for this study were having received trabectedin in 2nd line or beyond for ASTS, progressive disease after at least one previous line for ASTS and signed CI. A TMA was set up for FAS staining (Cell Signaling) with blocks from diagnostic time. Two expert blinded pathologists reviewed and classified the cases as negative, weak or strong. Kaplan–Meier estimations were used for time-to-event variables and the log-rank test was used to compare groups. Results: A series of 198 patients accomplished selection criteria. Metastases at diagnosis occurred in 46 (24%) and median time to metastases was 18.8 months (CI 16,3; 21.3). Previous line to trabectedin consisted of gemcitabine combination 83 (42%), Doxorubicin-based 65 (33%) and others 50 (25%). Median PFS for previous and trabectedin lines were 3.5 (2.8-4.2) and 3.4 (2.8-4) months respectively. FAS positive entailed significantly better PFS for the previous trabectedin line: 4.1 (1.5-6.7) vs 3.0 (2.5-3.5) months, p = 0.01 whereas FAS positive was related with worse PFS for the trabectedin line 2.5 (2.2-2.8) vs 3.7 (2.7-4.8) months, p = 0.028. These results were more notorious for L-sarcoma cases: 7.0 (3.6-10.5) vs 4.3 (1.9-6.6) months, p = 0.017 in previous line and 2.4 (2.2-2.6) vs 6.5 (3.8-9.3) months, p < 0.001 in trabectedin. From trabectedin administration, FAS+ had significantly worse OS especially in L-sarcomas: 11.9 (5.2-18.7) vs 21.7 (12.7-30.8) months, p = 0.002. Conclusions: FAS showed predictive value in PFS and OS for trabectedin administration in ASTS. The different prognostic role of FAS across distinct lines and its relevance in L-sarcomas deserve further attention.

Correlation between a new growth modulation index (GMI)-based Geistra score and efficacy outcomes in patients (PTS) with advanced soft tissue sarcomas (ASTS) treated with trabectedin (T): A Spanish group for research on sarcomas (GEIS-38 study)

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Background: The GMI is a marker of drug activity and represents an intra-patient comparison of successive time to progression (TTP), defined as the TTP ratio between the second (or later) line (TTPn) of therapy divided by the prior line (TTPn−1). Defining a clinical profile of pts with GMI >1.33 could help to identify pts who can gain greater benefit from T. Methods: We retrospectively evaluated the concordance between the GMI and the efficacy outcomes and clinical profiles of 198 pts with ASTS treated with trabectedin 1.5 mg/m² (24-h infusion q3w) as a 2nd or further-line treatment from Jan 2007 to Jun 2016. Results: After a median follow-up of 58 months (m; range: 18-172) median overall survival from ASTS diagnosis (MOS) and from T (MT-OS) were 27.5 m (23-32.1) and 10.8 m (8.9-12.7), respectively, while median TTP from T (MT-TTP) and T-1 were 3.4 m (2.8-4) and 3.5 m (2.8-4.2). Overall, 106 pts (53%) had a GMI <1; 22 (11%) a GMI=1-1.33 and 70 pts (35%) a GMI >1.33. A high GMI (<1.33 vs >1.33) correlated with favorable efficacy outcomes: MT-OS: 23 vs 36 m (p<0.001), MT-TTP 2.3 vs 8.2 m (p<0.001) and clinical benefit (objective response + stable disease) 23% vs 68% (p=0.001). The multivariate analysis identified L-type sarcoma (Odds ratio: 1.99, 95% CI 1.06-3.71), metastatic free interval (MFI) from initial diagnosis > 8.1 m (2.24, 95%CI 1.19-4.18) and Karnofsky >80 (2.3, 95%CI 1.00-5.28) as factors independently associated to GMI> 1.33. Based on these 3 variables we defined a new GEISTRA score assigning 1 point for each adversely affected variable: non L-Sarcoma, MFI<8.1m or Karnofsky <80. This score showed a strong correlation with MT-TTP (p<0.001) and MT-OS (p<0.001). Conclusions: Based on the high GMI we defined a new GEISTRA score, which is strongly associated with favorable efficacy outcomes in pts with ASTS treated with T. Thus, GEISTRA score could be a potentially useful predictable clinical tool for T benefit. [Table: see text]