Soft Tissue Sarcoma Patients Research Articles

Alteration of the Nucleotide Excision Repair (NER) Pathway in Soft Tissue Sarcoma.

Clinical responses to anticancer therapies in advanced soft tissue sarcoma (STS) are unluckily restricted to a small subgroup of patients. Much of the inter-individual variability in treatment efficacy is as result of polymorphisms in genes encoding proteins involved in drug pharmacokinetics and pharmacodynamics. The nucleotide excision repair (NER) system is the main defense mechanism for repairing DNA damage caused by carcinogens and chemotherapy drugs. Single nucleotide polymorphisms (SNPs) of NER pathway key genes, altering mRNA expression or protein activity, can be significantly associated with response to chemotherapy, toxicities, tumor relapse or risk of developing cancer. In the present study, in a cohort of STS patients, we performed DNA extraction and genotyping by SNP assay, RNA extraction and quantitative real-time reverse transcription PCR (qPCR), a molecular dynamics simulation in order to characterize the NER pathway in STS. We observed a severe deregulation of the NER pathway and we describe for the first time the effect of SNP rs1047768 in the ERCC5 structure, suggesting a role in modulating single-stranded DNA (ssDNA) binding. Our results evidenced, for the first time, the correlation between a specific genotype profile of ERCC genes and proficiency of the NER pathway in STS.

CINSARC in high-risk soft tissue sarcoma patients treated with neoadjuvant chemotherapy: Results from the ISG-STS 1001 study.

The Complexity INdex in SARComas (CINSARC) is a transcriptional signature derived from the expression of 67 genes involved in mitosis control and chromosome integrity. This study aims to assess CINSARC value of in an independent series of high-risk patients with localized soft tissue sarcoma (STS) treated with preoperative chemotherapy within a prospective, randomized, phase III study (ISG-STS 1001). Patients with available pre-treatment samples, treated with 3 cycles of either standard (ST) preoperative or histotype-tailored (HT) chemotherapy, were scored according to CINSARC (low-risk, C1; high-risk, C2). The 10-year overall survival probability (pr-OS) according to SARCULATOR was calculated, and patients were classified accordingly (low-risk, Sarc-LR, 10-year pr-OS>60%; high-risk, Sarc-HR, 10-year pr-OS<60%). Survival functions were estimated using the Kaplan-Meier method and compared using log-rank test. Eighty-six patients were included, 30 C1 and 56 C2, 49 Sarc-LR and 37 Sarc-HR. A low level of agreement between CINSARC and SARCULATOR was observed (Cohen's Kappa=0.174). The 5-year relapse-free survival in C1 and C2 were 0.57 and 0.55 (p= 0.481); 5-year metastases-free survival 0.63 and 0.64 (p= 0.740); 5-year OS 0.80 and 0.72 (p= 0.460). The 5-year OS in C1 treated with ST and HT chemotherapy was 0.84 and 0.76 (p= 0.251) respectively; in C2 treated it was 0.72 and 0.70 (p= 0.349). The 5-year OS in Sarc-LR treated with S and HT chemotherapy was 0.80 and 0.82 (p= 0.502) respectively; in Sarc-HR it was 0.70 and 0.61 (p= 0.233). Our results, although constrained by the small size of the series, suggest that CINSARC has weak prognostic power in high-risk, localized STS treated with neoadjuvant chemotherapy.

Correlative Study on the Relationship between the Expression of m6a-Related Genes and the Prognosis and Immunotherapy of Soft Tissue Sarcoma.

Soft tissue sarcomas (STS) are rare malignancies arising from mesenchymal tissue and interlacing ectodermal nerve tissue. Immunotherapy plays an important role in the prognosis and survival of STS patients. However, there is insufficient evidence to confirm the prognostic value of m6A-related genes and to evaluate the efficacy of immunotherapy for STS. We analyzed 23 m6A regulators from STS samples using R software and defined the modification patterns for three STS m6A regulators. Then, we constructed the m6A scores and divided the samples into high and low subgroups. Finally, we used data from the GEO database to verify the results. We found that the m6A clusters differed in the overall survival (OS), progression-free survival (PFS), and immune infiltration rate. Additionally, the m6A score was positively correlated with the contents of activated B cells, activated dendritic cells, CD56 bright natural killer cells, helper T cells, and regulatory T cells. The group with a higher m6A score also presented higher OS and PFS rates. Regarding immunotherapy, STS patients with a high m6A score presented better results. Consistently, we found similar results in another dataset with patients that received anti-PD-1/PD-L1 therapy. Our current results indicated that the m6A score can be used to assess the survival rate of STS patients and guide immunotherapy and predict its effects. The analysis of different m6A patterns of STS samples contributed to the understanding of the diversity and complexity of the tumor microenvironment (TME) and provided new ideas for the clinical development of personalized immunotherapy and prediction of the prognosis of STS patients.

Diagnosis of Marginal Infiltration in Soft Tissue Sarcoma by Radiomics Approach Using T2-Weighted Dixon Sequence.

Determination of preoperative soft tissue sarcoma (STS) margin is crucial for patient prognosis. To evaluate diagnostic performance of radiomics model using T2-weighted Dixon sequence for infiltration degree of STS margin. Retrospective. Seventy-two STS patients consisted of training (n=58) and test (n=14) sets. A 3.0 T; T2-weighted Dixon images. Pathologic result of marginal infiltration in STS (circumscribed margin; n=27, group 1, focally infiltrative margin; n=31, group 2-A, diffusely infiltrative margin; n=14, group 2-B) was the reference standard. Radiomic volume and shape (VS) and other (T2) features were extracted from entire tumor volume and margin, respectively. Twelve radiomics models were generated using four combinations of classifier algorithms (R, SR, LR, LSR) and three different inputs (VS, T2, VS + T2 [VST2] features) to differentiate the three groups. Three radiologists (reader 1, 2, 3) analyzed the marginal infiltration with 6-scale confidence score. Area under the receiver operating characteristic curve (AUC) and concordance rate. Averaged AUCs of R, SR, LR, LSR models were 0.438, 0.466, 0.438, 0.466 using VS features, 0.596, 0.584, 0.814, 0.815 using T2 features, and 0.581, 0.587, 0.821, 0.821 using VST2 features, respectively. The LR and LSR models constructed with T2 or VST2 features showed higher AUC and concordance rate compared to radiologists' analysis (AUC; 0.730, 0.675, 0.706, concordance rate; 0.46, 0.43, 0.47 in reader 1, 2, 3). Radiomics model constructed with features from tumor margin on T2-weighted Dixon sequence is a promising method for differentiating infiltration degree of STS margin. 4 TECHNICAL EFFICACY: Stage 2.

Pan-Soft Tissue Sarcoma Analysis of the Incidence, Survival, and Metastasis: A Population-Based Study Focusing on Distant Metastasis and Lymph Node Metastasis.

BackgroundThe rarity and complexity of soft tissue sarcoma (STS) make it a challenge to determine the incidence, survival, and metastasis rates. In addition, the clinicopathological risk factors for lymph node metastasis have rarely been reported.MethodsData on patients diagnosed with STS in the SEER database from 2000 to 2018 were extracted by SEER*Stat 8.3.9.1, and the incidence trend was calculated by Joinpoint 4.9 software. The KM method was used to calculate the survival curve, and the log-rank method was used to compare differences in the survival curves. The clinicopathological risk factors for lymph node metastasis were screened by logistic regression.ResultsAmong the 35987 patients, 4299 patients (11.9%) had distant metastasis. The overall lymph node metastasis rate was 6.02%, which included patients suffering from both lymph node and distant metastasis. Considering that some lymph node metastases might be accompanying events of distant metastasis, the rate of only lymph node metastasis in STS patients decreased to 3.42% after excluding patients with distant metastasis. Patients with only lymph node metastases (N1/2M0) had a significantly worse prognosis than those without metastases (N0M0) but a better prognosis than those with only distant metastases (N0M1) (p<0.0001). In the multivariate logistic analysis, STS patients with larger tumors located in the head and neck, viscera, retroperitoneum, and certain specific pathological subtypes (compared with the liposarcoma), such as undifferentiated pleomorphic sarcoma, rhabdomyosarcoma, endometrial stromal sarcoma, gastrointestinal stromal tumor, synovial sarcoma, and angiosarcoma, had a higher risk of lymph node metastasis.ConclusionsLymph node metastasis is rare in STS, and the metastasis rate is significantly different among the different pathological types. Tumor size, location, and pathological subtype are significantly associated with the risk of lymph node metastasis. The overall survival of patients with lymph node metastasis is better than that of patients with distant metastasis, which suggests a more precise prognosis evaluation should be performed in these AJCC stage IV STS patients.

Transcriptome Analysis of Tumor-Infiltrating Lymphocytes Identifies NK Cell Gene Signatures Associated With Lymphocyte Infiltration and Survival in Soft Tissue Sarcomas.

PurposeClinical successes using current T-cell based immunotherapies have been limited in soft tissue sarcomas (STS), while pre-clinical studies have shown evidence of natural killer (NK) cell activity. Since tumor immune infiltration, especially tumor-infiltrating lymphocytes, is associated with improved survival in most solid tumors, we sought to evaluate the gene expression profile of tumor and blood NK and T cells, as well as tumor cells, with the goal of identifying potential novel immune targets in STS.Experimental DesignUsing fluorescence-activated cell sorting, we isolated blood and tumor-infiltrating CD3-CD56+ NK and CD3+ T cells and CD45- viable tumor cells from STS patients undergoing surgery. We then evaluated differential gene expression (DGE) of these purified populations with RNA sequencing analysis. To evaluate survival differences and validate primary DGE results, we also queried The Cancer Genome Atlas (TCGA) database to compare outcomes stratified by bulk gene expression.ResultsSorted intra-tumoral CD3+ T cells showed significant upregulation of established activating (CD137) and inhibitory genes (TIM-3) compared to circulating T cells. In contrast, intra-tumoral NK cells did not exhibit upregulation of canonical cytotoxic genes (IFNG, GZMB), but rather significant DGE in mitogen signaling (DUSP4) and metabolic function (SMPD3, SLC7A5). Tumors with higher NK and T cell infiltration exhibited significantly increased expression of the pro-inflammatory receptor TLR4 in sorted CD45- tumor cells. TCGA analysis revealed that tumors with high TLR4 expression (P = 0.03) and low expression of STMN1 involved in microtubule polymerization (P < 0.001) were associated with significantly improved survival.ConclusionsUnlike T cells, which demonstrate significant DGE consistent with upregulation of both activating and inhibiting receptors in tumor-infiltrating subsets, NK cells appear to have more stable gene expression between blood and tumor subsets, with alterations restricted primarily to metabolic pathways. Increased immune cell infiltration and improved survival were positively correlated with TLR4 expression and inversely correlated with STMN1 expression within tumors, suggesting possible novel therapeutic targets for immunotherapy in STS.

A Newly Established Cuproptosis-Associated Long Non-Coding RNA Signature for Predicting Prognosis and Indicating Immune Microenvironment Features in Soft Tissue Sarcoma.

Cuproptosis, a new type of programmed cell death, is involved in the development and progression of malignancies. The study of cuproptosis-associated long non-coding RNAs (lncRNAs) in soft tissue sarcomas (STSs) is however limited. There is also uncertainty regarding the prognostic accuracy of cuproptosis-associated lncRNAs in STSs and their relationship to the tumor immune microenvironment. The aim of this study was to determine the prognostic significance of cuprotosis-associated lncRNAs in STSs and their relationship to the tumor immune microenvironment. Transcriptomic and clinical data from patients with STSs were obtained through The Cancer Genome Atlas (TCGA). Overall, 259 patients were randomly allocated to a training group or a testing group. In the training group, a cuproptosis-associated lncRNA signature was constructed, and the signature was verified in the testing group. On the basis of risk scores and clinical features, we later developed a hybrid nomogram. We also performed functional and tumor immune microenvironment analysis based on the cuproptosis-associated lncRNA signature. A signature of 5 cuproptosis-associated lncRNAs was created. Based on this signature, we categorized STS patients into high-risk and low-risk groups. The study showed that patients at high risk had a worse prognosis than those at low risk. A nomogram was then constructed combining clinical characteristics with the risk scores, and it was shown to have credible predictive power. Functional enrichment and tumor immune microenvironmental analyses showed that high-risk STSs tend to be immunologically sensitive tumors. In our study, we found a cuproptosis-associated lncRNAs signature, which serves as an independent prognostic indicator. Cuproptosis-associated lncRNAs may play a role in the tumor immune microenvironment, which might be a therapeutic target for patients with STSs.

In search of effective therapies: the current landscape of phase II trials in patients with advanced soft tissue sarcoma.

Soft tissue sarcomas (STS) are diagnosed in 4-6 cases per 100000 people a year and are associated with an unfavorable prognosis. Around one-third of patients will develop metastatic disease that requires palliative systemic therapy. Current therapeutic options have limited activity, and new treatments are tested, mainly in phase II trials. There is high variability and no standardization of phase II designs. We aimed to analyze the current landscape of phase II studies in STS and evaluate how its statistical design can affect the results. Full-text phase II studies published in STS patients between 2005 and 2020 were identified and analyzed. We have identified 102 trials, of which 77.4% were single-arm trials, 16.7% were randomized comparative trials (RCT), and 5.9% were randomized noncomparative trials. Including multiple cohorts, 22 randomized and 128 single-arm cohorts were analyzed. Nearly 80% of trials reported full statistical bases of the design. Over 20 different primary endpoints were used, with PFS as the most common in RCT trials (81.8%) and ORR (36.7%) and 3-months progression-free survival (PFS) rate (21.9%) in single-arm trials. Overall, 27.3% of RCT and 37.5% of single-arm trials were positive. Among single-arm trials, studies using 3- or 6-month rates were more often positive than those based on ORR. There is high heterogeneity in sarcoma trial designs, mainly in primary-endpoint and hypotheses used for size calculation. There is an unmet need for standardization that will incorporate factors associated with the rarity of the disease, outcomes detected in previous trials and real-life studies, and specific characteristics of new therapeutic agents.

Impact of allogeneic red blood cell transfusion on prognosis in soft tissue sarcoma patients. A single-centre study.

Perioperatively administered (leukocyte reduced) allogeneic red blood cell transfusions (lrRBCTs) may lead to transfusion-related immunomodulation and reduced overall survival (OS) in cancer patients. Herein, the effect of lrRBCT on local recurrence (LR), distant metastasis (DM), and OS in soft tissue sarcoma (STS) patients was analysed. Retrospective study on 432 STS patients (mean age: 60.0 ± 17.8 years; 46.1% female), surgically treated at a tertiary tumour centre. Uni- and multivariate survival models were calculated to analyse impact of perioperative lrRBCTs on LR, DM, OS. Perioperatively, 75 patients (17.4%) had received lrRBCTs. Older patients, deep, large, lower limb STS rather required lrRBCTs (all p < 0.05). No significant association between lrRBCT administration and LR- (p=0.582) or DM-risk (p=0.084) was observed. LrRBCT was associated with worse OS in univariate analysis (HR: 2.222; p < 0.001), with statistical significance lost upon multivariate analysis (HR: 1.658; p=0.059; including age, histology, size, grading, amputation, depth). Adding preoperative haemoglobin in subgroup of 220 patients with laboratory parameters revealed significant negative impact of low haemoglobin on OS (p=0.014), whilst effect of lrRBCT was further diminished (p=0.167). Unfavourable prognostic factors prevail in STS patients requiring lrRBCTs. Low haemoglobin levels rather than lrRBCT seem to reduce OS.

Reconstruction of the superficial femoral vessels with muscle flap coverage for soft tissue sarcomas of the proximal thigh.

BackgroundSurgical resection of soft tissue sarcoma with a margin of healthy tissue may necessitate resection and reconstruction of major blood vessels together with soft tissues of the proximal thigh to preserve the limb. The long‐term functional outcomes of these reconstructions remain unestablished. The aim of this report was to assess the vascular and functional outcomes of soft tissue sarcoma patients with femoral vessel reconstructions.Patients and MethodsPatients who had undergone oncovascular reconstruction during the treatment of proximal thigh soft tissue sarcoma in 2014–2020 were reviewed for details of the vascular and soft tissue reconstructions, and the oncological and functional outcomes. This included eight patients of a median age 59 (range 19–77) years. All had a reconstruction of at least the superficial femoral artery and vein as well as soft tissue reconstruction with a muscle flap. All vessel reconstructions were done with either autologous vein (six grafts/four patients) or allograft (10 grafts/six patients). A microvascular latissimus dorsi flap, with a skin island, was incorporated to cover the vascular grafts in five patients. A pedicled sartorius or gracilis muscle flap was used to fill the defect in three patients.ResultsGraft patency was assessed in seven patients with a median follow‐up of 48 (1–76) months. The arterial graft was patent in 6/8 and the vein graft in 2/8 patients. The gait had returned to normal in five of the six patients assessed. The median MTSS was 70 (43–87)% and the TESS 90 (75–100)%. No local recurrence of the sarcoma was detected.ConclusionsVascular reconstruction combined with soft tissue reconstruction enables limb‐sparing surgery in patients with soft tissue sarcoma involving proximal femoral vessels. Although the surgeries are complex with high early morbidity, the achieved long‐term functional outcomes are worthwhile.

A Necroptosis-Related lncRNA Signature Predicts Prognosis and Indicates the Immune Microenvironment in Soft Tissue Sarcomas.

Background: The necroptosis and long noncoding RNA (lncRNA) are critical in the occurrence and development of malignancy, while the association between the necroptosis-related lncRNAs (NRlncRNAs) and soft tissue sarcoma (STS) remains controversial. Therefore, the present study aims to construct a novel signature based on NRlncRNAs to predict the prognosis of STS patients and investigate its possible role. Methods: The transcriptome data and clinical characteristics were extracted from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression database (GTEx). A novel NRlncRNA signature was established and verified by the COX regression analysis and least absolute shrinkage and selection operator (LASSO) regression analysis. Subsequently, the K-M survival analysis, ROC, univariate, multivariate Cox regression analysis, and nomogram were used to evaluate the predictive value of the signature. Also, a variety of bioinformatic analysis algorithms explored the differences between the potential mechanism, tumor immune status, and drug sensitivity in the two-risk group. Finally, the RT-qPCR was performed to evaluate the expression of signature NRlncRNAs. Results: A novel signature consisting of seven NRlncRNAs was successfully established and verified with stable prediction performance and general applicability for STS. Next, the GSEA showed that the patients in the high-risk group were mainly enriched with tumor-related pathways, while the low-risk patients were significantly involved in immune-related pathways. In parallel, we found that the STS patients in the low-risk group had a better immune status than that in the high-risk group. Additionally, there were significant differences in the sensitivity to anti-tumor agents between the two groups. Finally, the RT-qPCR results indicated that these signature NRlncRNAs were abnormally expressed in STS. Conclusion: To the best of our knowledge, it is the first study to construct an NRlncRNA signature for STS. More importantly, the novel signature displays stable value and translational potential for predicting prognosis, tumor immunogenicity, and therapeutic response in STS.

Abstract CT216: A phase 0 master protocol utilizing a novel intratumoral microdosing approach for simultaneously evaluating multiple drugs and drug combinations in patients with solid tumors

Abstract Purpose/Objectives: Tumor responses to cancer treatments are highly context-specific and often involve complex interactions between the anti-cancer therapy, genetically diverse tumor cells, and a heterogeneous tumor microenvironment (TME). All preclinical models fall short in capturing this complexity. CIVO (Comparative In Vivo Oncology) is an intratumoral microdose injection research tool intended to bridge the translational gap between preclinical and clinical studies by enabling in situ assessment of up to 8 oncology drugs or drug combinations simultaneously within a patient’s tumor. The CIVO Phase 0 model was established under FDA’s exploratory IND guidelines for microdosing. A Master Protocol was then developed, enabling ongoing evaluation of multiple investigational drugs and combinations without a need for stand-alone new protocols. Each investigational drug or combination is specified as a substudy of the Master Protocol, thus reducing administrative burden to clinical site staff and creating an infrastructure to ensure quality data and oversight of patient safety. This is a multi-center, open-label Phase 0 Master Protocol designed to study the localized pharmacodynamics (PD) of anti-cancer therapies within the TME when administered intratumorally in microdose quantities via the CIVO device. The safety of intratumoral microdose administration via the CIVO device will also be evaluated. Materials/Methods: Approximately 12 subjects are expected to be enrolled per substudy. All substudies will evaluate subjects ≥18 years with a diagnosis of solid tumors with scheduled surgical intervention. Eligible subjects have at least one lesion (primary or recurrent tumor or effaced metastatic lymph node) ≥2 cm in the shortest diameter that is surface accessible for CIVO injection. Each substudy will define the tumor type and specific eligibility criteria for enrollment. The study visits consist of screening, CIVO injection, surgical intervention, and two follow-up visits. All patients will be injected by the CIVO device containing microdose quantities of drugs specified in respective substudies. The CIVO device can be configured with 3, 5, or 8 needles and the device configuration will be assigned on a per-patient basis, dependent upon lesion size. Following surgical resection, the injected portion of the tumor will undergo central PD biomarker analysis. At the time of submission, the study is open for enrollment with 1 substudy enrolling Head and Neck Squamous Cell Carcinoma (HNSCC) patients and 1 substudy enrolling HNSCC or soft tissue sarcoma patients. The Master Protocol was established to efficiently add substudies and accommodate evaluation of a wider repertoire of new agents in order to continually inform and de-risk drug development via the CIVO platform. Clinical trial information: NCT04541108. Citation Format: Karthik Rajasekaran, Jason G. Newman, Robert G. Maki, Thomas J. Ow, Vikas Mehta, Kenneth R. Gundle, Daniel R. Clayburgh, Ryan J. Li, Mercedes Porosnicu, Cherie-Ann O. Nathan, Alice Tang, Beryl A. Hatton, Kimberly H. Sottero, Gloria Kung, Marc O. Grenley, Kirsten Anderson, Richard A. Klinghoffer. A phase 0 master protocol utilizing a novel intratumoral microdosing approach for simultaneously evaluating multiple drugs and drug combinations in patients with solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT216.

Abstract 3424: Deep mechanistic profiling of immune oncology (I-O) drug combinations in cancer patients with CIVO® intratumoral microdosing and NanoString GeoMx DSP

Abstract Despite over four thousand clinical trials investigating combinations of various anti-cancer agents with immune checkpoint inhibitors (CPI), few have demonstrated significant clinical improvement over CPI alone. This indicates a need for approaches that can guide development of complex (≥ 3 drug) I-O combination treatments by enabling far greater mechanistic understanding of response to drug exposure by components of the authentic tumor microenvironment (TME). Here we show how an approach based on two technologies, the Presage Comparative In Vivo Oncology (CIVO) Platform and the NanoString GeoMx Digital Spatial Profiler (GeoMx DSP), highlights drug synergies as well as mechanisms of resistance to drug exposure in the native and intact TME of cancer patients, providing a path to rapid identification of effective drug combinations. The CIVO platform enables trackable multiplexed intratumoral delivery of microdosed drugs, either as single agents or in combinations, allowing evaluation of the localized tumor response to drug candidates in the TME while capturing tumor heterogeneity and patient diversity. GeoMx DSP is a method for high-plex spatial profiling of mRNAs with rare-cell sensitivity. Combining these technologies in Phase 0 clinical studies in human soft tissue sarcoma patients we evaluated distinct tumor sites microdosed with either nivolumab (anti-PD1), aldesleukin (recombinant IL-2), the combination of nivolumab and aldesleukin, vehicle (no drug), or chemotherapy controls. Using the Nanostring Cancer Transcriptome Atlas we evaluated the effect of drug exposure on expression of over 1,800 genes simultaneously with spatial resolution across individual patient tumors. Synergistic elevation of multiple transcripts was observed at tumor sites exposed to the combination of aldesleukin and nivolumab. This included T-cell specific elevation of granzyme B, a classic biomarker of T-cell activation. Importantly, we show how events such as T-cell activation may be dampened by feedback loops involving immune suppressive responses including, but not limited to, elevation of IDO-1 in non-T-cell components of the TME. Results were observed across multiple patient tumors and were verified by conventional immuno-histochemistry or in situ hybridization. Performing these studies across different patients allows us to explore the inter-individual variation in drug responses. We believe this is an efficient and biologically relevant approach to better understanding feedback loops activated within the authentic TME and ultimately prioritizing drug combinations for clinical development. Citation Format: Jason P. Frazier, Kenneth R. Gundle, Marc Grenley, Gloria Kung, Kimberly Sottero, Kirsten Anderson, Richard Klinghoffer, Jonathan M. Derry. Deep mechanistic profiling of immune oncology (I-O) drug combinations in cancer patients with CIVO® intratumoral microdosing and NanoString GeoMx DSP [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3424.

Abstract 3100: XenoSarc: patient-derived xenograft (PDX) models of soft tissue sarcoma (STS) and their histopathological and molecular characterization

Abstract STS constitutes a family of rare mesenchymal tumors with more than 70 subtypes described. The limited treatment options available for advanced STS patients underline the need for reliable preclinical models to test new therapeutic approaches. We established a panel of PDX models (XenoSarc) by subcutaneous implantation of fresh tumor specimens in athymic mice (nu/nu NRMI). Once tumor growth was observed, pieces of tumor were re-transplanted to next generations of animals. At each passage tumor fragments were collected for histopathological and molecular characterization. In an ongoing effort 493 STS samples from 414 consenting patients treated at the University Hospitals, Leuven (Belgium) have been transplanted. A total of 67 PDX models from 20 STS subtypes have been established, meaning they have stable morphological, immunohistochemical and genetic characteristics over at least 2 passages. The PDX platform includes more common STS subtypes such as myxofibrosarcoma (n=12 models), gastrointestinal stromal tumors (9), dedifferentiated liposarcoma (10), and leiomyosarcoma (8), as well as models from ultra-rare subtypes, e.g. pulmonary intimal sarcoma, extraskeletal osteosarcoma, mesenchymal chondrosarcoma, myxoinflammatory fibroblastic sarcoma and others. All relevant details about the donor patient and tumor characteristics, including sensitivity to the standard treatments, are known for every model. The models are well-characterized, with availability of molecular information on genomic profile (by low-coverage whole genome sequencing), and expression profile (by RNA sequencing). Xenografts are accompanied by ready to use tissue microarrays (TMA) from the models, which can be exploited for target identification and model selection for preclinical studies. Ex-mouse material can also be used to establish primary cell cultures and 3D organoids for in vitro screening purposes. The XenoSarc platform offers opportunities for studying the biology of various sarcoma subtypes including ultra-rare entities and was found to be a very reliable tool for early drug screening in STS in preparation of clinical testing of novel compounds. The platform is available for collaborative preclinical projects with academic and industrial partners. Citation Format: Agnieszka Wozniak, Luna De Sutter, Lore De Cock, Britt Van Renterghem, Che-Jui Lee, Yannick Wang, Ulla Vanleeuw, Kimberly Verbeeck, Daphne Hompes, Friedl Sinnaeve, Hazem Wafa, Baki Topal, Joris Jaekers, Dirk Van Raemdonck, Maria Debiec-Rychter, Raf Sciot, Patrick Schöffski. XenoSarc: patient-derived xenograft (PDX) models of soft tissue sarcoma (STS) and their histopathological and molecular characterization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3100.

Abstract 622: Development and characterization of a novel anti-PD1 resistant sarcoma mouse model

Abstract Background: Soft Tissue Sarcoma (STS) is known to be resistant to cancer immunotherapy including the prototypical immune checkpoint inhibitor (ICI) anti-PD1 (1). It’s therefore crucial to develop innovative strategies aiming at improving current clinical benefit. To this end, a well-characterized sarcoma preclinical model that mimics resistance to immunotherapy is needed. Starting from the anti-PD(L)1-sensitive MCA205 sarcoma mouse model, we therefore aimed at developing and characterizing a novel model resistant to anti-PD1. Methods: Anti-PDL1 antibody was first administered to the ICI-sensitive MCA205 mouse sarcoma model (MCA205-S) and tumor growth was followed overtime. Tumor from a “non-responder” animal - tumor growth profile being similar as in the vehicle group - was then retrieved and processed for tissue dissociation and cell culture. Tumor cells were then amplified and inoculated into immunocompetent C57BL/6 mice that were exposed or not to anti-PD1 antibody, and tumor growth was monitored for a 8-week period. In addition, tumor samples from satellite animals were collected and processed for intratumoral immune landscape characterization by multiparametric flow cytometry as well as for gene expression analysis by RNA sequencing. Results: While anti-PD1 antibody demonstrated a strong anti-tumor effect in MCA205-S tumor-bearing mice, administration of anti-PD1 to the mice inoculated with the non-responder mouse-originating MCA205 cells did not yield to a significant anti-tumor effect thereby validating the resistant profile of this new MCA205-R cell line. Flow cytometry analysis of tumor-infiltrated immune cells revealed a higher abundance of macrophages (defined as CD11b+/F4:80+) in MCA205-R when compared to the MCA205-S model, which more likely harbor a M2 phenotype. Also, anti-PD1 treatment favored an important MCA205-R tumor infiltration by gMDSC which was more limited in the MCA205-S model. Gene expression profile of tumor samples is currently under investigation. Conclusions: We developed and validated a novel preclinical mouse model of sarcoma (MCA205-R) characterized by its resistance to anti-PD1 and a high tumor infiltration by macrophages. This model - more reflecting the clinic in terms of immunotherapy sensitivity - can thus serve to evaluate novel immunotherapeutic regimens either alone or in combination with reference ICI, to ultimately translate into clinical benefit for STS patients treated with immunotherapy. Citation Format: Imane Nafia, Jean-Philippe Guegan, Assia Chaibi, Noëlie Bos, Doriane Bortolotto, Christophe Rey, Loïc Cerf, Florent Peyraud, Antoine Italiano, Alban Bessede. Development and characterization of a novel anti-PD1 resistant sarcoma mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 622.

Relation between Plasma Trough Concentration of Pazopanib and Progression-Free Survival in Metastatic Soft Tissue Sarcoma Patients.

Background: Pazopanib (PAZ) is an oral angiogenesis inhibitor approved to treat soft tissue sarcoma (STS) but associated with a large interpatient pharmacokinetic (PK) variability and narrow therapeutic index. We aimed to define the specific threshold of PAZ trough concentration (Cmin) associated with better progression-free survival (PFS) in STS patients. Methods: In this observational study, PAZ Cmin was monitored over the treatment course. For the primary endpoint, the 3-month PFS in STS was analyzed with logistic regression. Second, we performed exposure–overall survival (OS) (Cox model plus Kaplan–Meier analysis/log-rank test) and exposure–toxicity analyses. Results: Ninety-five STS patients were eligible for pharmacokinetic/pharmacodynamic (PK/PD) assessment. In the multivariable analysis, PAZ Cmin < 27 mg/L was independently associated with a risk of progression at 3 months (odds ratio (OR) 4.21, 95% confidence interval (CI) (1.47–12.12), p = 0.008). A higher average of PAZ Cmin over the first 3 months was associated with a higher risk of grade 3–4 toxicities according to the NCI-CTCAE version 5.0 (OR 1.07 per 1 mg/L increase, CI95 (1.02–1.13), p = 0.007). Conclusion: PAZ Cmin ≥ 27 mg/L was independently associated with improved 3-month PFS in STS patients. Pharmacokinetically-guided dosing could be helpful to optimize the clinical management of STS patients in daily clinical practice.

Anlotinib rechallenge combined with immune checkpoint inhibitor for advanced soft tissue sarcoma after the failure of anlotinib.

e23541 Background: The anti-angiogenic tyrosine kinase inhibitor (TKI) anlotinib has been approved for the treatment of advanced clear cell sarcoma, alveolar soft-part sarcoma, and other anthracycline-failed advanced soft tissue sarcoma (STS) in China. However, the management of refractory STS is still an unmet medical need. The formation of immunosuppressive microenvironment is one of the resistance mechanisms of anti-angiogenic therapy. This retrospectively observational study investigated the efficacy and safety of anlotinib rechallenge combined with immune checkpoint inhibitor (ICI) for advanced STS after progression on anlotinib treatment. Methods: A cohort of STS patients who had progressed after the anlotinib treatment were prescribed with anlotinib plus ICI were enrolled. Other concurrent systemic treatments were not allowed. Demographic features and clinical outcomes were reviewed and analyzed. Results: A total of 10 STS patients were included. The median of previous systemic treatment regimens was 3 (range, 1-5). Two cases (20%) were observed a partial response, including anlotinib plus nivolumab for a leiomyosarcoma and anlotinib plus toripalimab for an angiosarcoma. Another 4 patients achieved stable disease lasting more than 6 weeks. The median progression-free survival (PFS) were 4.8 months (95% CI: NA-12.5 months). Three (30%) patients developed grade 3 or higher adverse events including toxicity of skin/mucosal(n = 2) and neutrophile granulocyte decreased(n = 1). Conclusions: ICIs plus anlotinib rechallenges maybe a potential treatment for advanced STS patients after progression on anlotinib with acceptable adverse events.

Genetic abnormalities and aberrant expression of genes involved in chromosome segregation and mitosis in patients with chromosomally unstable malignant soft tissue tumors haboring extensive somatic loss-of-heterozygosity (LOH).

11576 Background: Malignant soft tissue tumor is a rare cancer with few therapeutic options. Recent genomic analysis of soft tissue sarcoma (STS) revealed a high degree of chromosomal instability (CIN) including genome-wide copy number alteration, aneuploidy, whole genome doubling and chromothripsis. In STS patients, we observed extensive somatic LOH, a hallmark of CIN, which is haploid of germline mutations/variants in cancer-related genes. CIN of STS genome implicates abnormalities in chromosome segregation and mitosis. So far, studies on this issue, however, have not been reported in STS patients. Methods: We recruited 155 patients with metastatic/recurrent malignant soft tissue tumors (135 female and 20 male, mean age 51 at analysis, 100 LMS, 19 LPS, 4 ESS, 3 UPS, 3 AS, 3 MPT, 3 GIST and others) with information of familial cancer burden. Whole exome sequencing and analysis were performed in both blood and tumor samples as described in 2018ASCO. KIF18A expression was assessed by immunohistochemistry. Results: Patients with tumors harboring less than 33% somatic LOH in a total of somatic and LOH mutations/variants in 595 COSMIC genes (n = 54) have a better prognosis than those (34-66%, n = 49, 67-100%, n = 52) with tumors harboring more LOH genes (5-year OS; 71% vs 52% or 46%, p = 0.0299, p = 0.0117, respectively). Neither TMB nor MSI status was associated with LOH. Of the genes involved in chromosome segregation and mitosis, we found that a family of ARHGAP genes which play a role in the spindle assembly and Aurora A kinase activation was frequently mutated in both tumor and germline genomes (n = 81 in a total of 155). Damaging ARHGAP mutations/variants in tumors are correlated with higher LOH values (54±3.4%, n = 81 vs. 39±3.3%, n = 74. mean±SE, p = 0.0021) and poor prognosis of patients (5-year OS; 58% n = 81 vs. 41% n = 74, p = 0.0098). We also found that elevated and robust expression of a mitotic kinesin KIF18A in tumors harboring higher LOH and/or damaging ARHGAP mutations/variants (n = 12) but not in lower LOH tumors without ARHGAP mutations/variants (n = 4). Conclusions: This study, for the first time, demonstrates that genetic abnormalities and aberrant expression of genes involved in chromosome segregation and mitosis in patients with malignant soft tissue tumors. The results reveal a novel target of drug discovery for incurable STS because CIN tumor cells are shown to be particularly vulnerable to KIF18A inhibition, while somatic, diploid cells are not.

Phase 1b/ 2 study of a radio-enhancer, PEP503 (NBTXR3), in combination with concurrent chemo-radiation in locally advanced or unresectable rectal cancer.

3603 Background: PEP503 (aka NBTXR3) is a novel radio-enhancer composed of functionalized hafnium oxide nanoparticles that increases the energy deposition of radiotherapy. A phase 3 study in soft tissue sarcoma patients has significantly increased pCR and R0 when PEP503 was added to preop radiotherapy. This phase 1b/2 study was conducted with the aim to identify a recommended phase 2 dose (RP2D), and evaluate the efficacy of PEP503 intratumoral injection in combination with concurrent chemoradiation (CCRT) in patients with locally advanced rectal cancer (LARC). Methods: Patients with stage T3-T4 LARC (or with unresectable disease) suitable for neoadjuvant CCRT were enrolled. An intratumoral single administration of PEP503 (multiple punctures) was done 24 to 72 hours prior to IMRT of 50 Gy in 25 fractions of 2 Gy per fraction over 5-6 weeks with concurrent capecitabine or 5-FU. Traditional 3 + 3 design with 4 levels, 5%, 10%, 15%, and 22%, of the baseline GTV as measured by MRI, of PEP503 were assessed in Phase Ib. PEP503 nanoparticles intratumoral dispersion was analyzed by CT-scan. Surgery was performed 8 to 12 weeks after the completion of CCRT for patients with resectable tumors. Body kinetics was evaluated in Phase Ib. (ClinicalTrials.gov, NCT02465593) Results: Thirty-two (32) patients (male/female: 20/12; median age 62 years, range 38 to 76) were enrolled (1 dropped out before starting CCRT). In Phase 1b, 20 patients were treated and dose was escalated to 22%. RP2D was then determined as 22% with 6 patients treated at this dose level without DLT. Twelve (12) patients were included in the Phase 2. One (1) (3.2%) and 19 (61.3%) of evaluable patients (n = 31) had CR and PR, respectively, as the best tumor response across dose levels. No patient progressed as all evaluable patients (n = 31) achieved disease control for a DCR of 100%. Furthermore, twenty-five patients underwent surgery, of which 24 (96%) had microscopically clear resection margins and 5 of them (20%) had pathological complete response (pCR). The G3 AEs were diarrhea, ileus, thrombocytopenia, urosepsis, procedural haemorrhage, wound complication, hypokalaemia, and myalgia (all in 3.1%). No G4 AE were observed. The results of CT scans for nanoparticles dispersion demonstrated PEP503 remained within the tumor without leakage to the surrounding healthy tissues, before and after CCRT. In most patients, hafnium was not detected or below the Lower Limit of Quantification (LLOQ) in the circulation 60 minutes after PEP503 injection and was not found in urine. Conclusions: A single intratumoral injection of PEP503 in locally advanced or unresectable rectal adenocarcinoma undergoing capecitabine or 5-FU based CCRT is feasible and safe. The preliminary observed efficacy results may warrant further examination in larger clinical studies. Clinical trial information: NCT02465593.

Trabectedin and hypofractionated radiation for high-risk, localized, and metastatic soft tissue sarcoma: A retrospective study.

11564 Background: Soft tissue sarcomas (STSs) are a heterogeneous group of cancers with high unmet need. Trabectedin (T) is an FDA-approved chemotherapy that blocks cell cycling and DNA repair pathways. Combination T and conventional radiation (XRT) in STS nonrandomized phase 1/2 trials demonstrated objective response rates (ORR) of 36-72% in localized and low burden metastatic disease, while pre-treated metastatic STS treated with T alone has an ORR of 10-14%. We hypothesize that the combination of T and hypofractionated radiation (hXRT) will exhibit a tolerable safety profile and improve ORR relative to historical outcomes with T or hXRT alone. Here we report our experience in the treatment of oligometastatic STS with combined T and hXRT. Methods: We reviewed our institutional experience to identify patients treated with T and XRT. We included patients with high risk localized or metastatic STS (majority of patients had metastatic disease at time of treatment). All patients received at least 1 cycle of T and concurrent XRT to at least 1 lesion. ORR and local control rate (LCR) were determined for irradiated lesions by RECIST 1.1. Results: Between 2020 – 2021, 9 STS patients with 21 tumors were treated at the University of Colorado with XRT and concurrent T. The median age was 39.2 (range 26.0 – 64.6) years. 8 patients had metastatic disease at the time of treatment. Treated tumor sites included 1 lung,1 extremity, 2 liver, 2 retroperitoneal, 5 bone, and 10 peritoneal. The following histologic subtypes were included: myxoid liposarcoma (3), uterine leiomyosarcoma (2), non-uterine leiomyosarcoma (1), dedifferentiated liposarcoma (1), undifferentiated pleomorphic sarcoma (1), and synovial sarcoma (1). All metastatic patients were pre-treated with a median of 3 lines of systemic therapy. The median number of T cycles delivered was 5 (range 1 – 20). The median XRT prescription dose was 3000cGy (range 2000cGy – 5000cGy), with 8 patients having received hXRT (5 -10 fractions) and 1 having received conventionally fractionated XRT. 8 patients underwent 1 course of XRT, while 1 received 3 courses in combination with T. All patients had a Karnofsky performance status equal to or greater than 60. After a median follow-up 5.4 months, the LCR of treated lesions was 90.5%. The ORR (CR or PR) was 57.1% and median decrease in tumor diameter at time of maximum response was 52.0%. The median time until maximum response was 3.7 months. 2 patients experienced grade 3 toxicity (LFT elevation) attributable to T, and 2 patients experienced grade 3 toxicity due to XRT. There were no grade 4 or 5 toxicities. Conclusions: T in combination with hXRT appears to be safe and feasible in this patient population. Based on these data, a phase 1/2 prospective clinical trial is being planned in oligometastatic and high risk localized STS. [Table: see text]