Characteristics and outcomes of patients with advanced sarcoma enrolled in early phase immunotherapy trials

Subtype-Specific Patterns of Tumor Purity and Mutation Load Suggest Treatment Implications: A Cross-Sectional Analysis of 7494 Soft Tissue and Bone Sarcomas (MSK Cohort)

OBJECTIVES

Sarcomas are complex mesenchymal malignancies whose molecular characteristics can significantly influence treatment strategies. This study aimed to investigate the relationship between tumor purity, mutation load, and clinical characteristics across sarcoma subtypes, focusing on potential implications for therapeutic stratification.

METHODS

This study analyzed the molecular characteristics of 7494 sarcoma cases from the Soft Tissue and Bone Sarcoma (MSK, Nat Commun 2022) data set using available case analysis. Correlations between tumor purity, mutation load, age, and sex were analyzed using nonparametric methods, with subtype-specific analyses conducted using Kruskal-Wallis tests and Bonferroni-corrected post hoc comparisons. A comprehensive analysis of mutation patterns was performed using microsatellite instability (MSI) status.

RESULTS

Significant correlations between mutation load and tumor purity (ρ=0.320, P <0.001) were identified, with marked heterogeneity across subtypes. Tumor purity ranged from 20.0% in brain sarcomas to 78.5% in dermatofibrosarcoma protuberans. Age-related molecular changes were observed in brain (ρ=0.711, P =0.006) and skin sarcomas (ρ=0.450, P =0.006), suggesting distinct evolutionary patterns. A subset of hypermutated, microsatellite stable cases (0.15%) with mutation loads exceeding 100 mutations/mb were identified, suggesting alternative mechanisms of genomic instability. MSI-high status was rare (0.24%) but associated with higher mutation loads (median: 25.84 vs. 2.42, P <0.001), particularly in uterine sarcomas (0.7% prevalence).

CONCLUSIONS

The identification of distinct molecular patterns across sarcoma subtypes challenge existing morphology-based classification systems and may hold implications for therapeutic stratification. These findings may help inform future immunotherapeutic and molecular-guided approaches to treatment in sarcoma patients, particularly for elderly patients with brain sarcomas or females with uterine sarcomas.

Macrophage and osteosarcoma cell crosstalk is dependent on oxygen tension and 3D culture

Osteosarcoma (OS), the most common form of primary bone cancer in young adults, has had no improvements in clinical outcomes in 50 years. This highlights a critical need to advance mechanistic understanding of OS to further therapeutic discovery, which will only be possible with accurate models of the disease. Compared to traditional monolayer studies and preclinical models, in vitro models that better replicate the three-dimensional (3D) bone marrow microenvironment will facilitate methodical investigations of the events and factors that drive OS progression. Herein, we use fibrin-alginate interpenetrating network (FA IPN) hydrogels to model the hematological bone marrow environment. We interrogated the effects of oxygen tension, 3D culture, and macrophage phenotype on OS behavior and specifically examine the immunomodulatory crosstalk between OS and macrophages. We observe that OS is more sensitive to oxygen tension when cultured in 3D. Specifically, both highly and less metastatic OS exhibit decreased changes in DNA content over time in 3D, but then demonstrate diverging behaviors in heterotypic culture with macrophages. OS response to macrophages differs as a function of metastatic potential, where highly metastatic OS shows increased immunosuppression that varies with oxygen tension but relies on direct coculture conditions. To our knowledge, this is among the first work to report the effects of 3D culture on the interplay between OS and macrophages in a coculture microenvironment. Together, these data introduce FA IPNs as a promising platform for cancer research and emphasize the importance of novel models for the mechanistic study of OS.

Bioinformatic analysis indicated that LINC01150 might be a novel neutrophil extracellular traps-related biomarker of gastric cancer

Gastric cancer (GC) is a highly aggressive malignancy associated with poor prognosis, particularly in its advanced stages. Neutrophil extracellular traps (NETs) have been implicated in cancer progression and immune therapy responses; however, the role of NETs-related long non-coding RNAs (lncRNAs) in GC remains poorly understood. This study used data from the Cancer Genome Atlas (TCGA) and previous research to identify NETs-related lncRNAs in GC. A prognostic signature comprising four NETs-related lncRNAs (NlncSig) was developed and validated, serving as a predictor for patient survival and response to immunotherapy. The NlncSig was correlated with poorer outcomes in high-risk patients and demonstrated that those with lower risk scores exhibited more favorable responses to immunotherapy. In vitro experiments confirmed that LINC01150 enhances GC cell proliferation, migration, and invasion. This robust NlncSig provides a reliable tool for predicting survival and immune characteristics in GC, with the potential to guide personalized therapeutic approaches and improve patient care.

Anlotinib plus TQB2450, a PD-L1 Antibody, in Patients with Advanced Alveolar Soft Part Sarcoma: A Single-Arm, Phase II Trial

PURPOSE

Alveolar soft part sarcoma (ASPS) is an ultrarare soft-tissue sarcoma with a high rate of metastasis and no established treatment. This study aimed to explore the efficacy and safety of anlotinib (a tyrosine kinase inhibitor) and TQB2450 (a PD-L1 inhibitor) in patients with ASPS.

PATIENTS AND METHODS

This single-arm, phase II study evaluated the efficacy of TQB2450, an anti-PD-L1 agent, combined with anlotinib, a tyrosine kinase inhibitor, in adults with advanced ASPS. TQB2450 was given intravenously (1,200 mg) on day 1, and anlotinib (12 mg/day) was taken orally from day 1 to 14 every 3 weeks. The primary endpoint was overall response rate, with secondary endpoints including duration of response, progression-free survival, and overall survival. Lymphocyte infiltration and tertiary lymphoid structure (TLS) were also analyzed as potential prognostic biomarkers.

RESULTS

The study enrolled 29 patients, of whom 28 were evaluable (one withdrew because of acute pancreatitis). An objective response was achieved in 82.1% of patients, including 4 complete and 19 partial responses. The median time to response was 2.8 months, and the duration of response was not reached, with an estimated median progression-free survival of 35.2 months. Grade 3 to 4 treatment-related adverse events occurred in 44.8% of patients, with no study-related deaths. Responders had a higher proportion of TLS area, TLS density, and CD20-positive immune cells.

CONCLUSIONS

The combination of anlotinib and TQB2450 is effective and tolerable in patients with ASPS. TLS may serve as a prognostic biomarker, meriting further investigation.

Association of Lung Immune Prognostic Index (LIPI) with Disease Control Rate and Progression-Free Survival in Patients with Soft-Tissue Sarcoma Treated with Immunotherapy in Early-Phase Trials

BACKGROUND

The efficacy of immunotherapies in soft-tissue sarcomas (STSs) is limited, and biomarkers of response are lacking. The lung immune prognostic index (LIPI) is a prognostic biomarker used with immunotherapy across cancer types. This study investigates the association of LIPI with the disease control rate (DCR) and progression-free survival (PFS) in patients with STS treated with immunotherapy versus other therapies in early-phase trials.

METHODS

This post hoc analysis was conducted with patients with STS from Gustave Roussy and Centre Léon Bérard between January 2012 and June 2021. The LIPI was calculated based on a derived neutrophil-to-lymphocyte ratio > 3 and elevated lactate dehydrogenase. Patients were categorized based on treatment (immunotherapy or other) and LIPI (good, intermediate, or poor). DCR was defined as the sum of stable disease and complete and partial response.

RESULTS

A total of 82 patients were enrolled in immunotherapy trials and 126 in the other therapy trials. In the immunotherapy group, DCR was higher in patients with good LIPI (76%; n = 23/30) compared with the intermediate (50%; n = 13/26) and poor LIPI groups (8%; n = 1/12; p < 0.001). The other-therapy group did not show significant differences in DCR by LIPI: DCR was 70% (n = 48/69), 70% (n = 21/30), and 60% (n = 6/10) in patients with good, intermediate, and poor LIPI, respectively (p = 0.86). In multivariate analyses, LIPI was independently associated with PFS in the immunotherapy group (hazard ratio = 5.97, p = 0.0001) and not in the control group (p = 0.71).

CONCLUSIONS

LIPI is a significant independent prognostic marker for DCR in patients with STS treated with immunotherapy. In early-phase trials, LIPI could be used as a screening tool for stratification at inclusion. High neutrophil levels, which correlate with a poorer LIPI score, are likely associated with immunotherapy resistance. This relationship could explain the statistical impact of poor LIPI in the immunotherapy group.

Unraveling molecular aberrations and pioneering therapeutic strategies in osteosarcoma

Osteosarcoma, a rare primary bone cancer, presents diverse molecular aberrations that underscore its complexity. Despite the persistent endeavors by researchers, the limited amelioration in the five-year survival rate indicates that current therapeutic strategies prove inadequate in addressing the clinical necessities. Advancements in molecular profiling have facilitated an enhanced comprehension of the biology of osteosarcoma, offering a promising outlook for treatment. There is an urgent need to develop innovative approaches to address the complex challenges of osteosarcoma, ultimately contributing to enhanced patient outcomes. This review explores the nexus between osteosarcoma and cancer predisposition syndromes, intricacies in its somatic genome, and clinically actionable alterations. This review covers treatment strategies, including surgery, chemotherapy, immune checkpoint inhibitors (ICIs), and tyrosine kinase inhibitors (TKIs). Innovative treatment modalities targeting diverse pathways, including multi-target tyrosine kinases, cell cycle, PI3K/mTOR pathway, and DNA damage repair (DDR), offer promising interventions. This review also covers promising avenues, including antibody-drug conjugates (ADCs) and immunotherapy strategies, such as cytokines, adoptive cellular therapy (ACT), ICIs, and cancer vaccines. This comprehensive exploration contributes to a holistic understanding, offering guidance for clinical applications to advance the management of osteosarcoma.

EMT-related gene classifications predict the prognosis, immune infiltration, and therapeutic response of osteosarcoma

BACKGROUND

Osteosarcoma (OS), a bone tumor with high ability of invasion and metastasis, has seriously affected the health of children and adolescents. Many studies have suggested a connection between OS and the epithelial-mesenchymal transition (EMT). We aimed to integrate EMT-Related genes (EMT-RGs) to predict the prognosis, immune infiltration, and therapeutic response of patients with OS.

METHODS

We used consensus clustering to identify potential EMT-Related OS molecular subtypes. Somatic mutation, tumor immune microenvironment, and functional enrichment analyses were performed for each subtype. We next constructed an EMT-Related risk signature and evaluated it by Kaplan-Meier (K-M) analysis survival and receiver operating characteristic (ROC) curves. Moreover, we constructed a nomogram to more accurately predict OS patients' clinical outcomes. Response effects of immunotherapy in OS patients was analyzed by Tumor Immune Dysfunction and Exclusion (TIDE) analysis, while sensitivity for chemotherapeutic agents was analyzed using oncoPredict. Finally, the expression patterns of hub genes were investigated by single-cell RNA sequencing (scRNA-seq) data analysis.

RESULTS

A total of 53 EMT-RDGs related to prognosis were identified, separating OS samples into two separate subgroups. The EMT-high subgroup showed favourable overall survival and more active immune response. Significant correlations were found between EMT-Related DEGs and functions as well as pathways linked to the development of OS. Additionally, a risk signature was established and OS patients were divided into two categories based on the risk scores. The signature presented a good predictive performance and could be recognized as an independent predictive factor for OS. Furthermore, patients with higher risk scores exhibited better sensitivity for five drugs, while no significant difference existed in immunotherapy response between the two risk subgroups. scRNA-seq data analysis displayed different expression patterns of the hub genes.

CONCLUSION

We developed a novel EMT-Related risk signature that can be considered as an independent predictor for OS, which may help improve clinical outcome prediction and guide personalized treatments for patients with OS.

Advancements in Diagnosis and Multimodal Treatment Strategies for Retroperitoneal Tumors: A Comprehensive Review

Retroperitoneal tumors (RPTs) encompass both benign and malignant entities, constituting ~0.1% to 0.2% of all malignant tumors, of which 70% to 80% manifest malignancy. Predominantly, retroperitoneal sarcomas (RPS) represent the most prevalent subtype among RPT. With over 70 histologic forms identified, liposarcomas and leiomyosarcomas emerge as the primary constituents of RPS. Accurate diagnosis of RPTs necessitates preoperative core-needle biopsy and comprehensive imaging assessment. The current staging protocol for RPS relies on the eighth edition of the American Joint Committee on Cancer/TNM classification. Surgical excision remains the established gold standard for treating RPS. Therapeutic approaches vary according to the underlying pathophysiology. Although chemotherapy and radiotherapy exhibit efficacy in managing metastatic and recurrent unresectable RPS, their role in primary RPS remains unresolved, necessitating further clinical trials for validation. Concurrently, ongoing research explores the potential of targeted therapies and immunotherapy. This literature review aims to provide a comprehensive overview of existing research, delineating diagnostic pathways and optimal therapeutic strategies for RPT.

Complete Response to Pembrolizumab in Stage IV Alveolar Soft Part Sarcoma After Failure of Four Lines of Treatment: A Case Report and Literature Review

Alveolar soft part sarcoma (ASPS) is a rare malignant tumor that manifests as a slow-growing soft tissue mass and frequently presents with distant metastasis. The prognosis is variable, and complete remission of metastatic disease has rarely been reported. Our patient was diagnosed with metastatic ASPS at the age of 17, with a primary forearm lesion and metastasis to the lungs. She underwent surgical resection of her forearm mass, followed by adjuvant chemotherapy and radiation to target the lung metastasis. Over the next decade, she had a complicated course of treatment. Her disease continued to slowly progress despite treatment with sunitinib, pazopanib, and a combination of docetaxel and gemcitabine. We eventually treated her with immune checkpoint inhibitors (ICIs). Pembrolizumab, initially in combination with bevacizumab and later as monotherapy, resulted in significant tumor shrinkage, especially in the pulmonary lesions, within the first three months. Subsequent imaging reported complete remission within 15 months and no disease recurrence at her three-year follow-up. Our case highlights one of the very few reported cases of complete remission achieved in metastatic ASPS after treatment with ICIs. ICIs could offer hope for disease remission in advanced ASPS, a rare malignancy that has proven difficult to treat successfully in the past. More studies need to be conducted to further evaluate the efficacy and any associated predictors of successful treatment.

Immunotherapy in Sarcoma: Current Data and Promising Strategies

Traditionally sarcomas have been considered immunologically quiet tumours, with low tumour mutational burden (TMB) and an immunosuppressive tumour microenvironment (TME), consisting of decreased T-cell infiltration and elevated levels of H1F1α, macrophages and neutrophils.1,2 However, research has shown that a subset of sarcomas are immunologically 'hot' with either high TMB, PDL-1 expression, CD8+ T cells or presence of tertiary lymphoid structures (TLS) demonstrating sensitivity to immunotherapy.3,4 Here, we review the current evidence for immunotherapy use in bone sarcomas (BS) and soft tissue sarcomas (STS), with immune checkpoint inhibitors (ICI) and adoptive cellular therapies including engineered T-cell therapies, chimeric antigen receptor (CAR) T-cell therapies, tumour infiltrating lymphocytes (TILs) and cancer vaccines and biomarkers of response.

Immune profiling of dedifferentiated liposarcoma and identification of novel antigens for targeted immunotherapy

Dedifferentiated liposarcoma (DDLS) is an aggressive, recurring sarcoma with limited treatments. T-cell immunotherapies selectively target malignant cells, holding promise against DDLS. The development of successful immunotherapy for DDLS requires a thorough evaluation of the tumor immune microenvironment and the identification and characterization of targetable immunogenic tumor antigens. To assess the complexity of the human DDLS tumor immune microenvironment and to identify target antigens, we used the nCounter NanoString platform, analyzing gene expression profiles across 29 DDLS and 10 healthy adipose tissue samples. Hierarchical clustering of tumors based on expression of tumor inflammation signature genes revealed two distinct groups, consisting of 15 inflamed tumors and 14 non-inflamed tumors, demonstrating tumor heterogeneity within this sarcoma subtype. Among the identified antigens, PBK and TTK exhibited substantial upregulation in mRNA expression compared to healthy adipose tissue controls, further corroborated by positive protein expression by IHC. This data shows considerable inter-tumoral heterogeneity of inflammation, which should be taken into consideration when designing an immunotherapy for DDLS, and provides a novel targetable antigen in DDLS. The results of this study lay the groundwork for the development of a novel immunotherapy for this highly aggressive sarcoma.

Atezolizumab as the First Systemic Therapy Approved for Alveolar Soft Part Sarcoma

OBJECTIVE

The objective was to review the pharmacology, efficacy, and safety of atezolizumab (Tecentriq) for the treatment of adult and pediatric patients aged 2 years and older with unresectable or metastatic alveolar soft part sarcoma (ASPS).

DATA SOURCES

A literature search was conducted using PubMed and MEDLINE databases, published abstracts, and ongoing studies from ClinicalTrials.gov between January 1, 1981, and May 31, 2023. Keywords included atezolizumab, Tecentriq, MPDL3280, immunotherapy, PD-L1, PD-1, pediatrics, sarcoma, and ASPS.

STUDY SELECTION AND DATA EXTRACTION

All English-language studies involving atezolizumab for ASPS were included and discussed.

DATA SYNTHESIS

Atezolizumab is an anti-programmed death-ligand 1 (PD-L1) monoclonal antibody designed to block the interaction between PD-L1 and the programmed cell death protein 1 (PD-1) receptor. Atezolizumab was granted approval by the FDA specifically for ASPS based on a phase II clinical trial in adult and pediatric patients (n = 49), which reported an overall response rate of 24% and a durable response rate at 6 and 12 months of 67% and 42%, respectively. Common grade 3/4 adverse reactions include musculoskeletal pain (8%), followed by hypertension (6%), weight gain (6%), headache (4%), and dizziness (4%).

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE IN COMPARISON WITH EXISTING DRUGS

Advanced ASPS is a high-risk disease with limited treatment options. Atezolizumab appears to be a viable treatment option in ASPS demonstrating clinical efficacy and a manageable toxicity profile.

CONCLUSIONS

With no other treatments that are FDA approved specifically for ASPS, and few demonstrating efficacy in the advanced setting, the approval of atezolizumab, including the first approval for pediatric patients, represents a landmark improvement to the therapeutic arsenal against this rare disease.

Evaluation of the efficacy and safety of immunotherapy in sarcoma: a two-center study

Background

Sarcoma is a highly heterogeneous malignancy with a poor prognosis. Although chemotherapy and targeted therapy have improved the prognosis to some extent, the efficacy remains unsatisfactory in some patients. The efficacy and safety of immunotherapy in sarcoma need further evaluation.

Methods

We conducted a two-center study of sarcoma patients receiving PD-1 immunotherapy at Tianjin Medical University Cancer Institute and Hospital and Henan Provincial Cancer Hospital. The treatment regimens included PD-1 inhibitor monotherapy and combination therapy based on PD-1 inhibitors. The observed primary endpoints were median progression-free survival (mPFS) and median overall survival (mOS). Survival curves were compared using the Kaplan-Meier method.

Results

A total of 43 patients were included from the two centers. The median follow-up time for all patients was 13 months (range, 1-48 months). In the group of 37 patients with advanced or unresectable sarcoma, the mPFS was 6 months (95%CI: 5-12 months), and the mOS was 16 months (95%CI: 10-28 months). The ORR was 10.8% (4/37), and the DCR was 18.9% (7/37). Subgroup analysis showed no significant differences in mPFS (p=0.11) and mOS (p=0.88) between patients with PD-L1 negative/positive expression. There were also no significant differences in mPFS (p=0.13) or mOS (p=0.72) between PD-1 inhibitor monotherapy and combination therapy. Additionally, there were no significant differences in mPFS (p=0.52) or mOS (p=0.49) between osteogenic sarcoma and soft tissue sarcoma. Furthermore, the results showed no significant differences in mPFS (p=0.66) or mOS (p=0.96) between PD-1 inhibitors combined with targeted therapy and PD-1 inhibitors combined with AI chemotherapy. Among the 6 patients receiving adjuvant therapy after surgery, the mPFS was 15 months (95%CI: 6-NA months), and the mOS was not reached. In terms of safety, most adverse events were mild (grade 1-2) and manageable. The most severe grade 4 adverse events were bone marrow suppression, which occurred in 4 patients but resolved after treatment. There was also one case of a grade 4 adverse event related to hypertension.

Conclusion

Immunotherapy is an effective treatment modality for sarcoma with manageable safety. Further inclusion of more patients or prospective clinical trials is needed to validate these findings.

Efficacy of tyrosine kinase inhibitors in patients with advanced or metastatic sarcomas after prior chemotherapy: A meta-analysis

BACKGROUND

Sarcoma is a heterogeneous malignancy arising from interstitial tissue. Anthracycline-based therapy is the first-line treatment recommended by guidelines for patients with locally advanced or metastatic unresectable sarcoma. Recently, targeted therapies, in particular tyrosine kinase inhibitors (TKIs), have made significant progress in the treatment of sarcoma, and their efficacy has been investigated in randomized controlled trials. The aim of this meta-analysis is to evaluate the efficacy of TKIs in patients with advanced or metastatic sarcoma who have previously received chemotherapy.

METHODS

We completed a meta-analysis after conducting literature searches in PubMed, Embase, and Cochrane. The single-drug, placebo-controlled, randomized controlled clinical trials of TKIs in patients with advanced or progressive sarcoma who have previously received chemotherapy are available for inclusion in the study. The observation results were objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS). The subgroup analysis was performed according to histological subtypes of sarcoma.

RESULTS

This study included 6 studies, including 1033 patients. The ORR (OR: 7.99, 95% CI: 3.62-19.61, P < .00001), DCR (OR: 2.54, 95% CI: 1.27-5.08, P = .009), PFS (HR: 0.46, 95% CI: 0.34-0.62, P < .00001), and OS (HR: 0.80, 95% CI: 0.67-0.96, P = .02) of patients treated with TKIs were better than those in the placebo group.

CONCLUSIONS

In patients with advanced sarcoma, TKIs have been shown to have advantages in terms of ORR, DCR and PFS and OS. Multi-targeted TKIs may be considered as one of the second-line treatment options for sarcoma patients who have received prior chemotherapy.

Role of Immunotherapy in Sarcomas

Sarcomas are a group of malignancies of mesenchymal origin with a plethora of subtypes. Given the sheer heterogeneity of various subtypes and the rarity of the disease, the management of sarcomas has been challenging, with poor patient outcomes. Surgery, radiation therapy and chemotherapy have remained the backbone of treatment in patients with sarcoma. The introduction of immunotherapy has revolutionized the treatment of various solid and hematological malignancies. In this review, we discuss the basics of immunotherapy and the immune microenvironment in sarcomas; various modalities of immunotherapy, like immune checkpoint blockade, oncolytic viruses, cancer-targeted antibodies, vaccine therapy; and adoptive cell therapies like CAR T-cell therapy, T-cell therapy, and TCR therapy.

Unresectable leiomyosarcoma of the inferior vena cava with right atrium tumor thrombus: when to deem this tumor inoperable? A case report and literature review

Leiomyosarcomas (LMS) of the inferior vena cava (IVC) are a rare form of retroperitoneal malignancy, and their venous extension to the right atrium is an even rarer event. These tumors pose a unique surgical challenge and often require a multidisciplinary team-based approach for their surgical treatment. We present a case of a 68-year-old man with primary LMS of the IVC with a tumor thrombus extending into the right atrium that was initially deemed inoperable. After extensive neoadjuvant chemo-radiation with minimal tumor effect, the patient underwent en bloc surgical resection of the tumor along with removal of the infrarenal IVC and right kidney and adrenal without the need for cardiopulmonary bypass. This case demonstrates the successful management of a primary LMS of the IVC with right atrial extension using a multimodal approach of neoadjuvant chemo-radiation and en bloc surgical resection without cardiopulmonary bypass. This strategy may offer a curative option for selected patients with these rare and aggressive tumors, improving their survival and quality of life.

The efficacy of immunotherapy and chemoimmunotherapy in patients with advanced rare tumors: A Turkish oncology group (TOG) study

INTRODUCTION

The advances in immune checkpoint inhibitors (ICIs) were relatively slow in rare tumors. Therefore, we conducted a multi-center study evaluating the efficacy of ICI monotherapy and the combination of ICIs with chemotherapy (CT) in patients with advanced rare tumors.

METHODS

In this retrospective cohort study, we included 93 patients treated with ICIs for NCI-defined rare tumors from the 12 cancer centers in Turkey. The primary endpoints were the overall response (ORR) and disease control rate (DCR).

RESULTS

The cohort's median age was 56, and 53.8% of the patients were male. The most frequent diagnosis was sarcoma (29%), and 81.7% of the patients were previously treated with at least one line of systemic therapy in the advanced stage. The ORR and DCR were 36.8% and 63.2%, respectively. The germ cell tumors had the lowest ORR (0%), while the Merkel cell carcinoma had the highest ORR to ICIs (57.1%). Patients treated with ICI + ICI or ICI plus chemotherapy combinations had higher ORR (55.2% vs. 27.6%, p = 0.012) and DCR (82.8% vs. 53.4%, p = 0.008). The median OS was 13.47 (95% CI: 7.79-19.15) months, and the six and 12-month survival rates were 71% and 52%. The median duration of response was 16.59 months, and the 12-month progression-free survival rate was 66% in responders. The median time-to-treatment failure was 5.06 months (95% CI: 3.42-6.71). Three patients had high-grade irAEs with ICIs (grade 3 colitis, grade 3 gastritis, and grade 3 encephalitis in one patient each).

CONCLUSION

We observed over 30% ORR and a 13-month median OS in patients with rare cancers treated with ICI monotherapy or ICI plus CT combinations. The response rates to ICIs or ICIs plus CT significantly varied across different tumor types. Responding patients had over 2 years of survival, highlighting a need for further trials with ICIs for patients with rare tumors.

Immune checkpoint inhibitors in sarcomas: a systematic review

Sarcomas are tumors that originate from mesenchymal cells. The variety of sarcomas' response to chemotherapy and the wide range of prognosis reflect their heterogeneity. In order to improve the rates of response, the research has been orientated toward other forms of therapy, such as targeted therapies and immunotherapy or toward combinations of them. Immune checkpoint inhibitors (ICIs) have been the highlight of immunotherapy in the last decade. Although ICIs are already included in the guidelines of different malignancies, their clinical benefit in sarcomas is still under study. Alveolar soft part sarcomas, undifferentiated pleomorphic sarcomas and other subtypes of sarcoma with high presence of tertiary lymphoid structures tend to respond to ICIs, but further investigation is still needed. Furthermore, the search of predictive biomarkers to determine the type of sarcomas that are sensitive to ICIs is still very challenging. This review will focus on the results of clinical trials, which examine the effect of ICIs and their combination with chemotherapy, targeted therapies and other forms of immunotherapy in sarcomas.

Efficacy of immune checkpoint inhibitors in alveolar soft-part sarcoma: results from a retrospective worldwide registry

BACKGROUND

Conventional cytotoxic drugs are not effective in alveolar soft-part sarcoma (ASPS). Immune checkpoint (programmed cell death protein 1/programmed death-ligand 1) inhibitors (ICIs) are promising drugs in ASPS. A worldwide registry explored the efficacy of ICI in ASPS.

MATERIALS AND METHODS

Data from adult patients diagnosed with ASPS and treated with ICI for advanced disease in expert sarcoma centers from Europe, Australia and North America were retrospectively collected, including demographics and data related to treatments and outcome.

RESULTS

Seventy-six ASPS patients, with a median age at diagnosis of 25 years (range 3-61 years), were registered. All patients received ICI for metastatic disease. Immunotherapy regimens consisted of monotherapy in 38 patients (50%) and combination in 38 (50%) (23 with a tyrosine kinase inhibitor). Among the 68 assessable patients, there were 3 complete responses and 34 partial responses, translating into an overall response rate of 54.4%. After a median follow-up of 36 months [95% confidence interval (CI) 32-40 months] since the start of immunotherapy, 45 (59%) patients have progressed on ICI, with a median progression-free survival (PFS) of 16.3 months (95% CI 8-25 months). Receiving ICI in first line (P = 0.042) and achieving an objective response (P = 0.043) correlated with a better PFS. Median estimated overall survival (OS) from ICI initiation has not been reached. The 12-month and 24-month OS rates were 94% and 81%, respectively.

CONCLUSIONS

This registry constitutes the largest available series of ASPS treated with ICI. Our results suggest that the ICI treatment provides long-lasting disease control and prolonged OS in patients with advanced ASPS, an ultra-rare entity with limited active therapeutic options.

FBXO38 mediates FGL1 ubiquitination and degradation to enhance cancer immunity and suppress inflammation

Upregulation of FGL1 helps tumors escape from immune surveillance, and therapeutic antibodies targeting FGL1 have potential as another immune checkpoint inhibitor. However, the underlying mechanism of high FGL1 protein level in cancers is not well defined. Here, we report that FBXO38 interacts with and ubiquitylates FGL1 to negatively regulate its stability and to mediate cancer immune response. Depletion of FBXO38 markedly augments FGL1 abundance, not only suppressing CD8+ T cell infiltration and enhancing immune evasion of tumor but also increasing inflammation in mice. Importantly, we observe a negative correlation of FBXO38 with FGL1 and IL-6 in non-small cell lung cancer specimens. FGL1 and IL-6 levels positively correlate with TNM (tumor, lymph node, metastasis) stages, while FBXO38 and the infiltrating CD8+ T cells negatively correlate with TNM stages. Our study identifies a mechanism regulating FGL1 stability and a target to enhance the immunotherapy and suggests that the combination of anti-FGL1 and anti-IL-6 is a potential therapeutic strategy for cancer immunotherapy.

Advances in treatment of alveolar soft part sarcoma: an updated review

Alveolar soft part sarcoma is a rare neoplasm of uncertain histogenesis that belongs to a newly defined category of ultra-rare sarcomas. The neoplasm is characterized by a specific chromosomal translocation, der (17) t(X; 17)(p11.2;q25), that results in ASPSCR1-TFE3 gene fusion. The natural history of alveolar soft part sarcoma describes indolent behaviour with slow progression in deep soft tissues of the extremities, trunk and head/neck in adolescents and young adults. A high rate of detection of distant metastasis at presentation has been reported, and the most common metastatic sites in decreasing order of frequency are the lung, bone and brain. Complete surgical resection remains the standard treatment strategy, whereas radiotherapy is indicated for patients with inadequate surgical margins or unresectable tumours. Although alveolar soft part sarcoma is refractory to conventional doxorubicin-based chemotherapy, monotherapy or combination therapy using tyrosine kinase inhibitors and immune checkpoint inhibitors have provided antitumor activity and emerged as new treatment strategies. This article provides an overview of the current understanding of this ultra-rare sarcoma and recent advancements in treatments according to the clinical stage of alveolar soft part sarcoma.

Atezolizumab for Advanced Alveolar Soft Part Sarcoma

BACKGROUND

Alveolar soft part sarcoma (ASPS) is a rare soft-tissue sarcoma with a poor prognosis and no established therapy. Recently, encouraging responses to immune checkpoint inhibitors have been reported.

METHODS

We conducted an investigator-initiated, multicenter, single-group, phase 2 study of the anti-programmed death ligand 1 (PD-L1) agent atezolizumab in adult and pediatric patients with advanced ASPS. Atezolizumab was administered intravenously at a dose of 1200 mg (in patients ≥18 years of age) or 15 mg per kilogram of body weight with a 1200-mg cap (in patients <18 years of age) once every 21 days. Study end points included objective response, duration of response, and progression-free survival according to Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, as well as pharmacodynamic biomarkers of multistep drug action.

RESULTS

A total of 52 patients were evaluated. An objective response was observed in 19 of 52 patients (37%), with 1 complete response and 18 partial responses. The median time to response was 3.6 months (range, 2.1 to 19.1), the median duration of response was 24.7 months (range, 4.1 to 55.8), and the median progression-free survival was 20.8 months. Seven patients took a treatment break after 2 years of treatment, and their responses were maintained through the data-cutoff date. No treatment-related grade 4 or 5 adverse events were recorded. Responses were noted despite variable baseline expression of programmed death 1 and PD-L1.

CONCLUSIONS

Atezolizumab was effective at inducing sustained responses in approximately one third of patients with advanced ASPS. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT03141684.).

Targeting signaling pathways in osteosarcoma: Mechanisms and clinical studies

Osteosarcoma (OS) is a highly prevalent bone malignancy among adolescents, accounting for 40% of all primary malignant bone tumors. Neoadjuvant chemotherapy combined with limb-preserving surgery has effectively reduced patient disability and mortality, but pulmonary metastases and OS cells' resistance to chemotherapeutic agents are pressing challenges in the clinical management of OS. There has been an urgent need to identify new biomarkers for OS to develop specific targeted therapies. Recently, the continued advancements in genomic analysis have contributed to the identification of clinically significant molecular biomarkers for diagnosing OS, acting as therapeutic targets, and predicting prognosis. Additionally, the contemporary molecular classifications have revealed that the signaling pathways, including Wnt/β-catenin, PI3K/AKT/mTOR, JAK/STAT3, Hippo, Notch, PD-1/PD-L1, MAPK, and NF-κB, have an integral role in OS onset, progression, metastasis, and treatment response. These molecular classifications and biological markers have created new avenues for more accurate OS diagnosis and relevant treatment. We herein present a review of the recent findings for the modulatory role of signaling pathways as possible biological markers and treatment targets for OS. This review also discusses current OS therapeutic approaches, including signaling pathway-based therapies developed over the past decade. Additionally, the review covers the signaling targets involved in the curative effects of traditional Chinese medicines in the context of expression regulation of relevant genes and proteins through the signaling pathways to inhibit OS cell growth. These findings are expected to provide directions for integrating genomic, molecular, and clinical profiles to enhance OS diagnosis and treatment.

Anti-PD-1 therapy in advanced sarcomas: is cutaneous primary site a stronger predictor of response than histologic subtype?

BACKGROUND

Immune checkpoint inhibitors (ICIs) have shown modest antitumor activity in unselected advanced sarcomas. Histology driven approach to patient selection is the current standard for off-label anti-programmed cell death 1 (PD1) immunotherapy use.

METHODS

We retrospectively reviewed the clinical characteristics and outcomes of patients with advanced sarcoma who were treated with off label anti-PD1 immunotherapy at our center.

RESULTS

A total of 84 patients with 25 histological subtypes were included. Nineteen patients (23%) had a cutaneous primary tumor site. Eighteen patients (21%) were classified as having clinical benefit, including 1 patient with complete response, 14 with partial response, and 3 with stable disease lasting over 6 months with previously progressive disease. Cutaneous primary site location was associated with higher clinical benefit rate (58% vs. 11%, p < 0.001), longer median PFS (8.6 vs. 2.5 months, p = 0.003) and OS (19.0 vs. 9.2 months, p = 0.011), compared to non-cutaneous primary. Patients with histological subtypes that pembrolizumab is indicated per current National Comprehensive Cancer Network guidelines had modestly higher rate of clinical benefit versus other histologies, however, the difference was statistically insignificant (29% vs. 15%, p = 0.182) and no statistically significant difference in PFS or OS was observed between these groups. Immune-related adverse events were more frequently seen among patients with clinical benefit (72% vs. 35%, p = 0.007).

CONCLUSIONS

Anti-PD1-based immunotherapy is highly efficacious in advanced sarcomas of cutaneous primary site. Cutaneous primary site location is a stronger predictor of ICI response than histologic subtype and should be accounted for in treatment guidelines and clinical trial design.

Advances in immunology and immunotherapy for mesenchymal gastrointestinal cancers

Mesenchymal gastrointestinal cancers are represented by the gastrointestinal stromal tumors (GISTs) which occur throughout the whole gastrointestinal tract, and affect human health and economy globally. Curative surgical resections and tyrosine kinase inhibitors (TKIs) are the main managements for localized GISTs and recurrent/metastatic GISTs, respectively. Despite multi-lines of TKIs treatments prolonged the survival time of recurrent/metastatic GISTs by delaying the relapse and metastasis of the tumor, drug resistance developed quickly and inevitably, and became the huge obstacle for stopping disease progression. Immunotherapy, which is typically represented by immune checkpoint inhibitors (ICIs), has achieved great success in several solid tumors by reactivating the host immune system, and been proposed as an alternative choice for GIST treatment. Substantial efforts have been devoted to the research of immunology and immunotherapy for GIST, and great achievements have been made. Generally, the intratumoral immune cell level and the immune-related gene expressions are influenced by metastasis status, anatomical locations, driver gene mutations of the tumor, and modulated by imatinib therapy. Systemic inflammatory biomarkers are regarded as prognostic indicators of GIST and closely associated with its clinicopathological features. The efficacy of immunotherapy strategies for GIST has been widely explored in pre-clinical cell and mouse models and clinical experiments in human, and some patients did benefit from ICIs. This review comprehensively summarizes the up-to-date advancements of immunology, immunotherapy and research models for GIST, and provides new insights and perspectives for future studies.

NSUN2 promotes osteosarcoma progression by enhancing the stability of FABP5 mRNA via m5C methylation

5-methylcytosine (m⁵C) modification, which is mainly induced by the RNA methyltransferase NSUN2 (NOP2/Sun domain family, member 2), is an important chemical posttranscriptional modification in mRNA and has been proven to play important roles in the progression of many cancers. However, the functions and underlying molecular mechanisms of NSUN2-mediated m⁵C in osteosarcoma (OS) remain unclear. In this study, we found NSUN2 was highly expressed in OS tissues and cells. We also discovered that higher expression of NSUN2 predicted poorer prognosis of OS patients. Our study showed that NSUN2 could promote the progression of OS cells. Moreover, we employed RNA sequencing, RNA immunoprecipitation (RIP), and methylated RIP to screen and validate the candidate targets of NSUN2 and identified FABP5 as the target. We observed that NSUN2 stabilized FABP5 mRNA by inducing m⁵C modification and further promoted fatty acid metabolism in OS cells. Moreover, both knocking down the expression of FABP5 and adding fatty acid oxidation inhibitor could counterbalance the promoting effect of NSUN2 on the progression of OS. Our study confirms that NSUN2 can up-regulate the expression of FABP5 by improving the stability of FABP5 mRNA via m⁵C, so as to promote fatty acid metabolism in OS cells, and finally plays the role in promoting the progression of OS. Our findings suggest that NSUN2 is a promising prognostic marker for OS patients and may serve as a potential therapeutic target for OS treatment. A schematic illustration was proposed to summarize our findings.

Cancer-Associated B Cells in Sarcoma

Despite being one of the first types of cancers studied that hinted at a major role of the immune system in pro- and anti-tumor biology, little is known about the immune microenvironment in sarcoma. Few types of sarcoma have shown major responses to immunotherapy, and its rarity and heterogeneity makes it challenging to study. With limited systemic treatment options, further understanding of the underlying mechanisms in sarcoma immunity may prove crucial in advancing sarcoma care. While great strides have been made in the field of immunotherapy over the last few decades, most of these efforts have focused on harnessing the T cell response, with little attention on the role B cells may play in the tumor microenvironment. A growing body of evidence suggests that B cells have both pro- and anti-tumoral effects in a large variety of cancers, and in the age of bioinformatics and multi-omic analysis, the complexity of the humoral response is just being appreciated. This review explores what is currently known about the role of B cells in sarcoma, including understanding the various B cell populations associated with sarcoma, the organization of intra-tumoral B cells in tertiary lymphoid structures, recent trials in immunotherapy in sarcoma, intra-tumoral immunoglobulin, the pro-tumor effects of B cells, and exciting future areas for research.

Examining Stripes on a Herd of Zebras: Impact of Genomic Matching for Ultrarare Sarcomas in Phase 1 Clinical Trials (SAMBA 102)

PURPOSE

Recently, the Connective Tissue Oncology Society published consensus guidelines for recognizing ultrarare sarcomas (URS), defined as sarcomas with an incidence ≤1 per 1,000,000. We assessed the outcomes of 56 patients with soft tissue, and 21 with bone sarcomas, enrolled in Phase 1 trials.

EXPERIMENTAL DESIGN

In this Sarcoma-Matched Biomarker Analysis (SAMBA-102 study), we reviewed records from patients on Phase 1 trials at the University of Texas MD Anderson Cancer Center between January 2013 and June 2021.

RESULTS

Among 587 sarcomas, 106 (18.1%) were classified as URS. Fifty (47%) were male, and the median age was 44.3 years (range, 19-82). The most common subtypes were alveolar soft part sarcoma (ASPS), chordoma, dedifferentiated chondrosarcoma, and sclerosing epithelioid fibrosarcoma. Compared with common sarcomas, median OS was similar 16.1 months [95% confidence interval (CI), 13.6-17.5] versus 16.1 (95% CI, 8.2-24.0) in URS (P = 0.359). Objective response to treatment was higher in URS 13.2% (n = 14/106) compared with common sarcomas 6.9% (n = 33/481; P = 0.029). Median OS for those treated on matched trials was 27.3 months (95% CI, 1.9-52.7) compared with 13.4 months (95% CI, 6.3-20.6) for those not treated on matched trials (P = 0.291). Eight of 33 (24%) molecularly matched treatments resulted in an objective response, whereas 6 of 73 unmatched treatments (8.2%) resulted in an objective response (P = 0.024). Clinical benefit rate was 36.4% (12/33) in matched trials versus 26.0% (19/73) in unmatched trials (P = 0.279).

CONCLUSIONS

The results demonstrate the benefit of genomic selection in Phase 1 trials to help identify molecular subsets likely to benefit from targeted therapy.

Intratumoral STING activation causes durable immunogenic tumor eradication in the KP soft tissue sarcoma model

Introduction

Soft tissue sarcomas (STS) are highly metastatic, connective-tissue lineage solid cancers. Immunologically, sarcomas are frequently characterized by a paucity of tumor infiltrating lymphocytes and an immune suppressive microenvironment. Activation of the STING pathway can induce potent immune-driven anti-tumor responses within immunogenic solid tumors; however, this strategy has not been evaluated in immunologically cold sarcomas. Herein, we assessed the therapeutic response of intratumoral STING activation in an immunologically cold murine model of undifferentiated pleomorphic sarcoma (UPS).

Materials and Results

A single intratumoral injection of the murine STING agonist, DMXAA resulted in durable cure in up to 60% of UPS-bearing mice. In mice with synchronous lung metastases, STING activation within hindlimb tumors resulted in 50% cure in both anatomic sites. Surviving mice all rejected UPS re-challenge in the hindlimb and lung. Therapeutic efficacy of STING was inhibited by lymphocyte deficiency but unaffected by macrophage deficiency. Immune phenotyping demonstrated enrichment of lymphocytic responses in tumors at multiple timepoints following treatment. Immune checkpoint blockade enhanced survival following STING activation.

Discussion

These data suggest intratumoral activation of the STING pathway elicits local and systemic anti-tumor immune responses in a lymphocyte poor sarcoma model and deserves further evaluation as an adjunctive local and systemic treatment for sarcomas.

Targeted therapies and checkpoint inhibitors in sarcoma

Sarcomas are defined as a group of mesenchymal malignancies with over 100 heterogeneous subtypes. As a rare and difficult to diagnose entity, micrometastasis is already present at the time of diagnosis in many cases. Current treatment practice of sarcomas consists mainly of surgery, (neo)adjuvant chemo- and/or radiotherapy. Although the past decade has shown that particular genetic abnormalities can promote the development of sarcomas, such as translocations, gain-of-function mutations, amplifications or tumor suppressor gene losses, these insights have not led to established alternative treatment strategies so far. Novel therapeutic concepts with immunotherapy at its forefront have experienced some remarkable success in different solid tumors while their impact in sarcoma remains limited. In this review, the most common immunotherapy strategies in sarcomas, such as immune checkpoint inhibitors, targeted therapy and cytokine therapy are concisely discussed. The programmed cell death (PD)-1/PD-1L axis and apoptosis-inducing cytokines, such as TNF-related apoptosis-inducing ligand (TRAIL), have not yielded the same success like in other solid tumors. However, in certain sarcoma subtypes, e.g. liposarcoma or undifferentiated pleomorphic sarcoma, encouraging results in some cases when employing immune checkpoint inhibitors in combination with other treatment options were found. Moreover, newer strategies such as the targeted therapy against the ancient cytokine macrophage migration inhibitory factor (MIF) may represent an interesting approach worth investigation in the future.

Managing patients with advanced soft tissue sarcoma: Evolving landscape from an Australian perspective

AIM

Despite lack of advances in the first-line systemic therapy, the overall survival (OS) has continued to improve in patients with advanced soft tissue sarcoma (STS) with the recent estimation of median OS at 20 months. Several systemic therapy options are available now for the second-line and beyond, with more treatment tailored to histology and molecular subtype. The aim of this retrospective study was to characterize current patterns of care in managing patients with advanced STS (aSTS) in Australia.

METHODS

Sarcoma databases from 7 Australian sarcoma services were accessed to identify patients diagnosed with locally advanced inoperable and/or metastatic STS between January 1, 2010 and December 31, 2015. Baseline clinicopathological factors and initial treatment patterns were descriptively analyzed. For the Victorian cohort where treatment of aSTS and follow-up details were available, further exploratory analysis was conducted to determine the impact of patient and tumor characteristics and the use of palliative-intent treatment OS.

RESULTS

Of 2261 cases of STS, 671 were deemed as aSTS. Two thirds were relapsed disease with a mean 1.9 years from initial diagnosis. Median age at diagnosis of aSTS was 59 years (18-95 years) and 56.3% was male. Histology classification revealed four main subtypes: undifferentiated pleomorphic sarcoma (UPS) (23.1%), leiomyosarcoma (18.2%), liposarcoma (12.8%), synovial sarcoma (8.2%), and other comprising 14 STS subtypes. For the Victorian cohort (N = 361), approximately 80% of patients accessed palliative-intent treatment of various modalities. Nearly 40% of patients underwent tumor-debulking surgery or metastasectomy, of which lung wedge resection was the most common (N = 83, 47.7%). A total of 438 palliative-intent radiotherapy treatments were delivered to 259 patients (71.7%), with the majority in the form of external beam radiotherapy. Palliative-intent systemic therapy was delivered to 51.5% of patients (N = 186), mostly (73%). Anthracycline-based therapy was the most commonly delivered therapy (N = 135, 72.6%). Approximately half of the patients in each line of therapy failed to proceed to the subsequent line of systemic therapy with 29.4% receiving three or more lines of therapy (N = 55). A total of 18.3% of patient (N = 34) participated in clinical trials or accessed off-label drugs. The median OS for the Victoria cohort was 15.4 months (95% confidence interval: 12.1, 18.2). The UPS histology subtype was associated with poorer OS, whereas receiving any modality of palliative-intent treatment conferred survival benefit.

CONCLUSION

In Australia, aSTS is managed with diverse treatment approaches comprising various therapy modalities. Further work is planned in describing healthcare resource utilization and estimating costs by this patient cohort.

Comparative Combinatorial Implications and Theranostics of Immunotherapy in the Impediment of Alveolar Soft Part Sarcoma

BACKGROUND

Immune checkpoint inhibitors (ICIs), specifically programmed cell death receptor- 1/ligand 1 (PD-1/L1) inhibitors, have shown potential pharmacological efficacy in several cancers. Nonetheless, data pertinent to their therapeutic efficacy in alveolar soft-part sarcoma (ASPS) are limited.

OBJECTIVE

The retrospective aspects of ICIs (anti-PD1/PD-L1 blockers) to target ASPS are comparatively analyzed for clinical outcomes with other targeted immunotherapy modalities.

METHODS

We have conducted a systematic review without statistical analysis or comprehensive meta-analysis by collecting the articles published between 1952 and Sep 10th, 2020, by searching the following words: alveolar soft part sarcoma and immunotherapy including immune checkpoint, immune checkpoint inhibitors, and PD-1, PD-L1. We performed a pooled analysis of case reports, conferences, clinical trials, and other research reports pertinent to the efficacy of a PD-1 or PD-L1 antagonist in patients diagnosed with metastatic ASPS.

RESULTS

The effective studies include 10 case reports, 2 conference reports, 5 clinical trials, and 2 additional research reports. A total of 110 patients were reported to be enrolled in the pooled analysis; among them, 87 (78.38%) received a PD-1/PD-L1 antagonist. For patients who received anti-PD-1/PD-L1as monotherapy, their clinical response rates (CRR) were 63.22% whereas those who received targeted therapy and immunotherapy had a CRR of 78.95% (15/19). In the patients treated with double immunotherapy, their CRR was 100% (4/4). Tumor mutational burden and mismatch repair status have significant implications for predicting the ASPS prognosis.

CONCLUSION

Alveolar soft-part sarcoma patients with distant metastases can exhibit better clinical outcomes with immunotherapy, particularly toripalimab, atezolizumab, and axitinib combinatorial regimen with pembrolizumab. In addition, this review describes the therapeutic implications to guide personalized medicine depending on the expression patterns of PD-1/PD-L1 during the immunotherapy with ASPS.

Development of a pediatric physiologically-based pharmacokinetic model to support recommended dosing of atezolizumab in children with solid tumors

Background: Atezolizumab has been studied in multiple indications for both pediatric and adult patient populations. Generally, clinical studies enrolling pediatric patients may not collect sufficient pharmacokinetic data to characterize the drug exposure and disposition because of operational, ethical, and logistical challenges including burden to children and blood sample volume limitations. Therefore, mechanistic modeling and simulation may serve as a tool to predict and understand the drug exposure in pediatric patients.

Objective: To use mechanistic physiologically-based pharmacokinetic (PBPK) modeling to predict atezolizumab exposure at a dose of 15 mg/kg (max 1,200 mg) in pediatric patients to support dose rationalization and label recommendations.

Methods: A minimal mechanistic PBPK model was used which incorporated age-dependent changes in physiology and biochemistry that are related to atezolizumab disposition such as endogenous IgG concentration and lymph flow. The PBPK model was developed using both in vitro data and clinically observed data in adults and was verified across dose levels obtained from a phase I and multiple phase III studies in both pediatric patients and adults. The verified model was then used to generate PK predictions for pediatric and adult subjects ranging from 2- to 29-year-old.

Results: Individualized verification in children and in adults showed that the simulated concentrations of atezolizumab were comparable (76% within two-fold and 90% within three-fold, respectively) to the observed data with no bias for either over- or under-prediction. Applying the verified model, the predicted exposure metrics including C_min, C_max, and AUC_tau were consistent between pediatric and adult patients with a geometric mean of pediatric exposure metrics between 0.8- to 1.25-fold of the values in adults.

Conclusion: The results show that a 15 mg/kg (max 1,200 mg) atezolizumab dose administered intravenously in pediatric patients provides comparable atezolizumab exposure to a dose of 1,200 mg in adults. This suggests that a dose of 15 mg/kg will provide adequate and effective atezolizumab exposure in pediatric patients from 2- to 18-year-old.

A novel immune cell signature for predicting osteosarcoma prognosis and guiding therapy

Dysregulation of immune cell infiltration in the tumor microenvironment contributes to the progression of osteosarcoma (OS). In the present study, we explored genes related to immune cell infiltration and constructed a risk model to predict the prognosis of and guide therapeutic strategies for OS. The gene expression profile of OS was obtained from TARGET and Gene Expression Omnibus, which were set as the discovery and verification cohorts. CIBERSORT and Kaplan survival analyses were used to analyze the effects of immune cells on the overall survival rates of OS in the discovery cohort. Differentially expressed gene (DEG) analysis and protein–protein interaction (PPI) networks were used to analyze genes associated with immune cell infiltration. Cox regression analysis was used to select key genes to construct a risk model that classified OS tissues into high- and low-risk groups. The prognostic value of the risk model for survival and metastasis was analyzed by Kaplan–Meier survival analyses, receiver operating characteristic curves, and immunohistochemical experiments. Immunological characteristics and response effects of immune checkpoint blockade (ICB) therapy in OS tissues were analyzed using the ESTIMATE and Tumor Immune Dysfunction and Exclusion algorithms, while sensitivity for both targeted and chemotherapy drugs was analyzed using the OncoPredict algorithm. It was demonstrated that the high infiltration of resting dendritic cells in OS tissues was associated with poor prognosis. A total of 225 DEGs were found between the high- and low-infiltration groups of OS tissues, while 94 genes interacted with others. Through COX analyses, among these 94 genes, four genes (including AOC3, CDK6, COL22A1, and RNASE6) were used to construct a risk model. This risk model showed a remarkable prognostic value for survival rates and metastasis in both the discovery and verification cohorts. Even though a high microsatellite instability score was observed in the high-risk group, the ICB response in the high-risk group was poor. Furthermore, using OncoPredict, we found that the high-risk group OS tissues were resistant to seven drugs and sensitive to 25 drugs. Therefore, our study indicates that the resting dendritic cell signature constructed by AOC3, CDK6, COL22A1, and RNASE6 may contribute to predicting osteosarcoma prognosis and thus therapy guidance.

Fibrinogen like protein-1 knockdown suppresses the proliferation and metastasis of TU-686 cells and sensitizes laryngeal cancer to LAG-3 blockade

OBJECTIVE

To detect the expression of fibrinogen like protein-1 (FGL-1) in laryngeal cancer and evaluate its effect on tumor proliferation, metastasis, and antitumor immunity.

METHODS

ELISA and immunohistochemistry were performed to detect FGL-1 expression in laryngeal cancer. The effects of FGL-1 knockdown on the proliferation, cell cycle progression, apoptosis, migration, and invasion of laryngeal cancer cells were evaluated by the CCK-8, colony formation, flow cytometry, Transwell migration, and western blot assays. We detected changes in tumorigenesis and drug response in vivo following FGL-1 knockdown as well as the effects of anti-LAG3 immunotherapy. Immunohistochemistry was performed to determine CD8 and LAG-3 expression in mouse tumor tissues.

RESULTS

FGL-1 was highly expressed in the plasma and tumor tissues of laryngeal cancer patients. FGL-1 knockdown suppressed the proliferation of TU-686 cells and inhibited the migration and invasion of laryngeal cancer by blocking epithelial-to-mesenchymal transition. Moreover, silencing FGL-1 inhibited tumorigenicity in vivo and synergized with anti-LAG3 immunotherapy.

CONCLUSIONS

We confirmed the high expression of FGL-1 in laryngeal cancer and identified FGL-1 as a potential marker for immunotherapy in laryngeal cancer.

Global research trends on precision cancer medicine-related rashes (2008-2021): A bibliographic study

Background

Precision cancer medicine-related rashes are a kind of skin and mucous lesions caused by precision therapy. More and more evidences indicated that such events should not be ignored in the course of anti-tumor therapy. Since cancer treatment entered the “Precision Era”, there has been a rapid increase in this field. However, there was few bibliometric studies to provide an overall review of this field. This study aims to evaluate the literature output and trends in researches on precision cancer medicine-related rashes from a global perspective.

Methods

Collected publications on precision cancer medicine-related rashes from the Web of Science Core Collection database, which were limited to articles and reviews in English. Microsoft Excel, VOS viewer and CiteSpace V were used for quantitative and visual analysis.

Results

A total of 1,229 papers were identified. From 2008 to 2021, annual publications increased year by year. The United States published the most papers in this field (44.9%) and ranking first in citation frequency (19,854 times) and H-index (69). The University of Texas system ranks first with 98 papers published. Lacouture M.E and Robert C were the principal investigators. Cancers has the largest number of articles published, with 70 articles. In recent years, there have been research hotspots related to immunotherapy, including ipilimumab, immunotherapy, tumor microenvironment, association, checkpoint inhibitor, and cutaneous adverse event.

Conclusion

Precision cancer medicine-related rashes are a hot research topic in oncology. The number of relevant publications will increase dramatically. “Checkpoint inhibitors”, “skin adverse events”, “associations” and “tumor microenvironment” may become research hotspots in the future.

Immune checkpoints in osteosarcoma: Recent advances and therapeutic potential

Osteosarcoma is the most common primary malignant bone tumor and is associated with a high risk of recurrence and distant metastasis. Effective treatment for osteosarcoma, especially advanced osteosarcoma, has stagnated over the past four decades. The advent of immune checkpoint inhibitor (ICI) has transformed the treatment paradigm for multiple malignant tumor types and indicated a potential therapeutic strategy for osteosarcoma. In this review, we discuss recent advances in immune checkpoints, including programmed cell death protein-1 (PD-1), programmed cell death protein ligand-1 (PD-L1), and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), and their related ICIs for osteosarcoma treatment. We present the main existing mechanisms of resistance to ICIs therapy in osteosarcoma. Moreover, we summarize the current strategies for improving the efficacy of ICIs in osteosarcoma and address the potential predictive biomarkers of ICIs treatment in osteosarcoma.

Comprehensive Analysis of the Significance of Ferroptosis-Related Genes in the Prognosis and Immunotherapy of Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a life-threatening disease, associated with poor prognosis and the absence of specific biomarkers. Studies have shown that the ferroptosis-related genes (FRGs) can be used as tumor prognostic markers. However, FRGs’ prognostic value in OSCC needs further exploration. In our study, gene expression profile and clinical data of OSCC patients were collected from a public domain. We performed univariate and multivariate Cox regression analyses to construct a multigene signature. The Kaplan-Meier and receiver operating characteristic (ROC) methods were used to test the effectiveness of the signature, followed by the expression analysis of human leukocyte antigen (HLA) and immune checkpoints. The Cox regression analysis identified 4 hubs from 103 FRGs expressed in OSCC that were associated with overall survival (OS). A risk model based on the 4 FRGs was established to classify patients into high-risk and low-risk groups. Compared with the low-risk group, the survival time of the high-risk group was significantly reduced. According to the multivariate Cox regression analysis, the risk score acted as an independent predictor for OS. The accuracy of the 4 FRGs risk predictive model was confirmed by ROC curve analysis. Moreover, the low-risk group had the characteristics of higher expression of HLA and immune checkpoints, a lower tumor purity, and a higher immune infiltration, indicating a more sensitive response to immunotherapy. The novel FRGs-OSCC risk score system can be used to predict the prognosis of OSCC patients and their response to immunotherapy.

Pan-sarcoma characterization of lncRNAs in the crosstalk of EMT and tumour immunity identifies distinct clinical outcomes and potential implications for immunotherapy

The epithelial-to-mesenchymal transition (EMT) is a reversible process that may interact with tumour immunity through multiple approaches. There is increasing evidence demonstrating the interconnections among EMT-related processes, the tumour microenvironment, and immune activity, as well as its potential influence on the immunotherapy response. Long non-coding RNAs (lncRNAs) are emerging as critical modulators of gene expression. They play fundamental roles in tumour immunity and act as promising biomarkers of immunotherapy response. However, the potential roles of lncRNA in the crosstalk of EMT and tumour immunity are still unclear in sarcoma. We obtained multi-omics profiling of 1440 pan-sarcoma patients from 19 datasets. Through an unsupervised consensus clustering approach, we categorised EMT molecular subtypes. We subsequently identified 26 EMT molecular subtype and tumour immune-related lncRNAs (EILncRNA) across pan-sarcoma types and developed an EILncRNA signature-based weighted scoring model (EILncSig). The EILncSig exhibited favourable performance in predicting the prognosis of sarcoma, and a high-EILncSig was associated with exclusive tumour microenvironment (TME) characteristics with desert-like infiltration of immune cells. Multiple altered pathways, somatically-mutated genes and recurrent CNV regions associated with EILncSig were identified. Notably, the EILncSig was associated with the efficacy of immune checkpoint inhibition (ICI) therapy. Using a computational drug-genomic approach, we identified compounds, such as Irinotecan that may have the potential to convert the EILncSig phenotype. By integrative analysis on multi-omics profiling, our findings provide a comprehensive resource for understanding the functional role of lncRNA-mediated immune regulation in sarcomas, which may advance the understanding of tumour immune response and the development of lncRNA-based immunotherapeutic strategies for sarcoma.

New Drug Approvals for Sarcoma in the Last 5 Years

Sarcoma and locally aggressive connective tissue tumors are a complex group of diseases with a growing number of histotypes in the most recent WHO classification. Most of these tumors are rare (incidence <6/10⁵/y) or ultrarare (<1/10⁶/y). Despite their rarity, sarcomas are often good models for the development of personalized medicine, and a large number of new clinical trials in select histotypes and molecular subsets were reported during the past 5 years, leading to a faster rate of new drug approvals. We analyzed the published literature and the abstracts reported in major congresses dedicated to sarcoma and connective tissue tumor management in the last 5 years. Several targeted therapies, cytotoxic treatments, and immunotherapies have demonstrated activity in dedicated histologic and molecular subtypes of sarcomas. The majority of the studies for ultrarare entities are uncontrolled studies, as a consequence of the rarity of histotypes, but randomized controlled trials were available in the less rare histotypes. Most successful trials were based on biomarker selection, which were often driver molecular alterations, while a large number of ongoing research programs aim to identify biomarkers in parallel to new drug development. Availability of the new agents varies across countries. This article describes the new drugs that made it through to the finish line and new agents with promising activity that are in later stages of investigation in the large family of malignant connective tissue tumors.

The Role of Immunotherapy in the Management of Soft Tissue Sarcomas: Current Landscape and Future Outlook

Soft tissue sarcomas (STS) are a subset of sarcoma, a rare group of heterogeneous malignancies of mesenchymal origin. Current standard of care involves surgical resection with systemic chemotherapy used to treat high-risk localized and metastatic disease. Though classically thought to be immunologically quiet tumors, STS interact with the immune system, undergoing immunoediting that alters tumor immunogenicity and the tumor microenvironment. Recent advances with immune checkpoint inhibition have led to clinical trials exploring the efficacy of immunotherapy in treating STS. Results from these trials point to histologic subtype-specific clinical activity of immune checkpoint blockade. In addition, combinatorial strategies adding immune checkpoint inhibition to local or systemic therapies for STS have further increased their efficacy. Targeted immunotherapies using engineered T-cell receptor-based approaches also show increasing promise as treatment options for some patients with STS. Adoptive transfer of autologous T cells targeting NY-ESO-1 and MAGE-A4 have high response rates in sarcomas expressing these antigens, although recurrence is often seen in responding patients. Future work must focus on identifying primary and acquired mechanisms of resistance to these therapies, and extend T-cell receptor discovery to other tumor-associated antigens.

Immunotherapy of sarcomas with modified T cells

PURPOSE OF REVIEW

To summarize the development of modified T-cell therapies in sarcomas and discuss relevant published and ongoing clinical trials to date.

RECENT FINDINGS

Numerous clinical trials are underway evaluating tumor-specific chimeric antigen receptor T cells and high affinity T-cell receptor (TCR)-transduced T cells in sarcomas. Notably, translocation-dependent synovial sarcoma and myxoid/round cell liposarcoma are the subject of several phase II trials evaluating TCRs targeting cancer testis antigens New York esophageal squamous cell carcinoma-1 (NY-ESO-1) and melanoma antigen-A4 (MAGE A4), and response rates of up to 60% have been observed for NY-ESO-1 directed, modified T cells in synovial sarcoma. Challenges posed by modified T-cell therapy include limitations conferred by HLA-restriction, non-immunogenic tumor microenvironments (TME), aggressive lymphodepletion and immune-mediated toxicities restricting coinfusion of cytokines.

SUMMARY

Cellular therapy to augment the adaptive immune response through delivery of modified T cells is an area of novel therapeutic development in sarcomas where a reliably expressed, ubiquitous target antigen can be identified. Therapeutic tools to improve the specificity, signaling, proliferation and persistence of modified TCRs and augment clinical responses through safe manipulation of the sarcoma TME will be necessary to harness the full potential of this approach.

Quercetin encapsulated in Folic Acid-Modified Liposomes is therapeutic against osteosarcoma by non-Covalent binding to the JH2 Domain of JAK2 Via the JAK2-STAT3-PDL1

Osteosarcoma (OS) is a malignant solid tumor prone to lung metastasis that occurs in adolescents aged 15-19 years. Neoadjuvant chemotherapy and surgical treatment aimed at curing OS have gained limited progress over the last 30 years. Exploring new effective second-line therapies for OS patients is a serious challenge for researchers. Quercetin, a multiple biologically active polyphenolic flavonoid, has been used in tumor therapy. However, the exact mechanism of quercetin is still unknown, which limits the application of quercetin. In the current study, we found that quercetin could inhibit JAK2 through the JH2 domain in a non-covalent manner, resulting in the inhibition of OS proliferation and immune escape via the JAK2-STAT3-PD-L1 signaling axis. More importantly, to overcome the shortcomings of quercetin, including low water solubility and low oral availability, we encapsulated it with folic acid-modified liposomes. The transportation of quercetin by folic acid-modified liposomes may provide a feasible strategy to cure OS.

Case Report: Two Cases of Soft-Tissue Sarcomas: High TMB as a Potential Predictive Biomarker for Anlotinib Combined With Toripalimab Therapy

Soft-tissue sarcomas (STS), with over 100 different histologic subtypes, are rare tumors that account for 1% of all adult malignancies. Immune checkpoint inhibitors (ICIs) display certain benefits in some subtypes, especially in undifferentiated pleomorphic sarcoma (UPS), alveolar soft part sarcoma (ASPS), and leiomyosarcoma (LMS). However, efficacy is difficult to predict. High tumor mutational burden (TMB-H) and programmed death-ligand 1 (PD-L1) expression are the strongest features associated with the efficacy of immunotherapy, although they are rarely found in STS patients. Until now, whether or not PD-L1 expression and TMB are related to the efficacy of immunotherapy has not been determined. In this study, we report data obtained from two STS patients, one ASPS and one UPS with a high TMB, that benefited from anlotinib combined with toripalimab following resistance to anlotinib monotherapy. A 26 year-old female patient was diagnosed with ASPS. PD-L1 was negative. Next generation sequencing (NSG) revealed ASPSCR1-TFE3 fusion and TMB-H. Following eight months of anlotinib monotherapy, the patient’s disease progressed but continued to benefit from subsequent use of anlotinib combined with toripalimab for 19 months. Another 63 year-old male patient was diagnosed with UPS. PD-L1 was positive and NGS revealed TMB-H. Following 19 months of anlotinib monotherapy, the patient’s disease progressed but continued to benefit from subsequent use of anlotinib combined with toripalimab. DFS is 23 months to follow-up time. The results presented are the first to report the relationship between TMB and the efficacy of immunotherapy in STS. Based on our results, we hypothesis that anlotinib combined with toripalimab is effective for the treatment of some advanced ASPS or UPS. TMB may be a potential predictive biomarker for ICI treatment and deserves additional study.

Immune Checkpoint Inhibitors in Cancer Therapy

The discovery of immune checkpoint proteins such as PD-1/PDL-1 and CTLA-4 represents a significant breakthrough in the field of cancer immunotherapy. Therefore, humanized monoclonal antibodies, targeting these immune checkpoint proteins have been utilized successfully in patients with metastatic melanoma, renal cell carcinoma, head and neck cancers and non-small lung cancer. The US FDA has successfully approved three different categories of immune checkpoint inhibitors (ICIs) such as PD-1 inhibitors (Nivolumab, Pembrolizumab, and Cemiplimab), PDL-1 inhibitors (Atezolimumab, Durvalumab and Avelumab), and CTLA-4 inhibitor (Ipilimumab). Unfortunately, not all patients respond favourably to these drugs, highlighting the role of biomarkers such as Tumour mutation burden (TMB), PDL-1 expression, microbiome, hypoxia, interferon-γ, and ECM in predicting responses to ICIs-based immunotherapy. The current study aims to review the literature and updates on ICIs in cancer therapy.

Immunotherapy in soft tissue sarcoma: current evidence and future perspectives in a variegated family of different tumour

INTRODUCTION

In the last few years steps forward in the knowledge of the biology of soft tissue sarcomas (STS) has led to the development of new therapeutic strategies, including immunotherapy.

AREAS COVERED

This review outlines the recent findings on immunological features and provides a synopsis of the results of clinical trials with different immunotherapy approaches in STS, discussing criticisms and how the efficacy of immunotherapy could be improved.

EXPERT OPINION

The heterogeneity of STS has limited generalized approaches of immunotherapy in the disease. Clinical decisions should encompass a comprehensive characterization of the tumour microenvironment (TME), marked by intra-histotype diversity. Profiling of immune cells, checkpoint molecules and antigen target/HLA expression is deemed to re-shape the classical histotype classification for a selection of the most appropriate immune-based treatment. In a synergistic view, tumour-directed treatments, designed on the genetic and epigenetic histotype make-up, should be monitored for their immunomodulant effect and applied to ensure or amplify immunotherapy response. In light of the dynamic nature of the TME, this immunomonitoring should be conducted at baseline and during treatment, for improved therapeutic decisions and rational sequence of treatment combination, pursuing an immunological marker approach by histotype guidance.

Early phase trials in soft-tissue sarcomas: clinical benefit of inclusion in early lines of treatment, molecular screening, and histology-driven trials

BACKGROUND

The prognosis of patients with advanced soft-tissue sarcomas (STS) remains dismal, and systemic therapeutic options are limited. Early phase trials are becoming increasingly safe and effective. This study aimed to identify the prognostic factors for progression-free survival (PFS).

PATIENTS AND METHODS

This retrospective analysis included all STS patients participating in early phase trials at Gustave Roussy and Léon Bérard between 1 January 2012 and 31 December 2020.

RESULTS

Overall, 199 patients accounted for 214 inclusions in advanced STS. The most frequent histotypes were well-differentiated/dedifferentiated liposarcomas (n = 55), leiomyosarcomas (n = 53), synovial sarcomas (n = 22), undifferentiated pleomorphic sarcomas (n = 15), angiosarcomas (n = 12), and myxoid liposarcomas (n = 10). The median PFS was 2.8 months (95% confidence interval 2.7-4.1 months). The median PFS in the first, second, and later lines was 8.3, 5.4, and 2.6 months, respectively (P = 0.00015). The median PFS was 2.8 months in case of molecular screening, 4.1 months in case of histology-driven screening, and 1.6 months (P = 0.00014) in the absence of either screening modalities. In univariate analysis, histotype (P = 0.026), complex genomics (P = 0.008), number of prior lines (P < 0.001), prior anthracyclines (P < 0.001), number of metastatic sites (P = 0.003), liver metastasis (P < 0.001), lung metastasis (P < 0.001), absence of molecular or histology-driven screening (P < 0.001), first-in-human trials (P < 0.001), dose-escalation cohorts (P = 0.011), and Royal Marsden Hospital (RMH) score >1 (P < 0.001) were significantly associated with shorter PFS. In multivariate analysis, independent prognostic factors for shorter PFS were myxoid liposarcoma (P = 0.031), ≥2 prior lines of treatment (P = 0.033), liver metastasis (P = 0.007), and RMH score >2 (P = 0.006). Factors associated with improved PFS were leiomyosarcomas (P = 0.010), molecular screening (P = 0.025), and histology-driven screening (P = 0.010). The median overall survival rates were 36.3, 12.6, and 9.2 months in the first, second, and later lines, respectively (P = 0.0067). The grade 3-4 toxicity rate was 36%.

CONCLUSIONS

Early phase trials provide an active therapeutic option for STS, even in first-line settings. Molecular screening and histology-driven trials further improve the clinical benefit.

Novel Immunotherapies for Osteosarcoma

Osteosarcoma (OS) is the most common primary malignant bone sarcoma mainly affecting adolescents and young adults, which often progresses to pulmonary metastasis and leads to the death of OS patients. OS is characterized as a highly heterogeneous cancer type and the underlying pathologic mechanisms triggering tumor progress and metastasis are incompletely recognized. Surgery combined with neoadjuvant and postoperative chemotherapy has elevated 5-year survival to over 70% for patients with localized OS tumors, as opposed to only 20% of patients with recurrence and/or metastasis. Therefore, novel therapeutic strategies are needed to overcome the drawbacks of conventional treatments. Immunotherapy is gaining momentum for the treatment of OS with an increasing number of FDA-approved therapies for malignancies resistant to conventional therapies. Here, we review the OS tumor microenvironment and appraise the promising immunotherapies available in the management of OS.

Current Status and Future Directions of Immunotherapies in Soft Tissue Sarcomas

Immunotherapy in soft tissue sarcoma (STS) has experienced a surge of interest in the past decade, contributing to an expanding number of therapeutic options for this extremely heterogenous group of rare malignancies. Immune checkpoint inhibitors (CPIs) targeting the PD-1 and CTLA-4 axes have demonstrated promising responses in a select number of STS subtypes, including rarer subtypes, such as alveolar soft part sarcoma, SWI/SNF-deficient sarcomas, clear cell sarcoma, and angiosarcoma. Multiple pan-subtype sarcoma trials have facilitated the study of possible predictive biomarkers of the CPI response. It has also become apparent that certain therapies, when combined with CPIs, can enhance response rates, although the specific mechanisms of this possible synergy remain unconfirmed in STS. In addition to CPIs, several other immune targeting agents, including anti-tumour-associated macrophage and antigen-directed therapies, are now under assessment in STS with promising efficacy in some subtypes. In this article, we review the state of the art in immunotherapy in STS, highlighting the pre-clinical and clinical data available for this promising therapeutic strategy.