B7H3-Directed Intraperitoneal Radioimmunotherapy With Radioiodinated Omburtamab for Desmoplastic Small Round Cell Tumor and Other Peritoneal Tumors: Results of a Phase I Study

State of the art and perspectives of chimeric antigen receptor T cells cell therapy for neuroblastoma

Neuroblastoma (NB) is a solid, neuroendocrine pediatric solid tumor with divergent clinical behavior. Patients with high-risk diseases have poor prognoses despite complex multimodal therapy, which requires the search for new therapeutic approaches. Chimeric antigen receptor T cells (CAR-T) have led to dramatic improvements in the survival of cancer patients, most notably those with hematologic malignancies. Early-phase clinical trials of CAR-T cell therapy for NB have proven safe and feasible, but limited clinical efficacy. At the same time, multiple experimental and preclinical studies have shown that the most common in clinical trials single 2nd or 3rd generation CAR structure is not sufficient for a complete response in solid tumors. Here, we review the recent advances and future perspectives associated with engineered receptors, including several antigens binding, armored CAR-T of 4th and 5th generation and CAR-T cell combination strategies with other immunotherapy. We also summarize the results and shortcomings of ongoing clinical trials of CAR-T therapy for NB.

Comparison of approaches for increasing affinity of affibody molecules for imaging of B7-H3: dimerization and affinity maturation

BACKGROUND

Radionuclide molecular imaging can be used to visualize the expression levels of molecular targets. Affibody molecules, small and high affinity non-immunoglobulin scaffold-based proteins, have demonstrated promising properties as targeting vectors for radionuclide tumour imaging of different molecular targets. B7-H3 (CD276), an immune checkpoint protein belonging to the B7 family, is overexpressed in different types of human malignancies. Visualization of overexpression of B7-H3 in malignancies enables stratification of patients for personalized therapies. Affinity maturation of anti-B7-H3 Affibody molecules as an approach to improve the binding affinity and targeting properties was recently investigated. In this study, we tested the hypothesis that a dimeric format may be an alternative option to increase the apparent affinity of Affibody molecules to B7-H3 and accordingly improve imaging contrast.

RESULTS

Two dimeric variants of anti-B7-H3 Affibody molecules were produced (designated ZAC12*-ZAC12*-GGGC and ZAC12*-ZTaq_3-GGGC). Both variants were labelled with Tc-99m (99mTc) and demonstrated specific binding to B7-H3-expressing cells in vitro. [99mTc]Tc-ZAC12*-ZAC12*-GGGC showed subnanomolar affinity (KD1=0.28 ± 0.10 nM, weight = 68%), which was 7.6-fold higher than for [99mTc]Tc-ZAC12*-ZTaq_3-GGGC (KD=2.1 ± 0.9 nM). Head-to-head biodistribution of both dimeric variants of Affibody molecules compared with monomeric affinity matured SYNT-179 (all labelled with 99mTc) in mice bearing B7-H3-expressing SKOV-3 xenografts demonstrates that both dimers have lower tumour uptake and lower tumour-to-organ ratios compared to the SYNT-179 Affibody molecule.

CONCLUSION

The improved functional affinity by dimerization does not compensate the disadvantage of increased molecular size for imaging purposes.

Abdominopelvic desmoplastic small round cell tumor with metastasis: A case report and literature review

RATIONALE

Desmoplastic small round cell tumor (DSRCT) is a rare and rapidly metastasizing soft tissue sarcoma, distinguished by its unique cell morphology and pleomorphic differentiation.

PATIENT CONCERNS

This report describes the case of an 18-year-old male diagnosed with abdominopelvic DSRCT exhibiting metastases to the peritoneum, liver, pleura, bone, and muscle. The patient primarily presented with symptoms of incomplete intestinal obstruction and an abdominal mass.

DIAGNOSES

Colonoscopy revealed lumen stenosis caused by external compression mass. Contrast-enhanced computed tomography and 18F-fluorodeoxyglucose positron emission tomography/computed tomography revealed multiple lesions in the abdominopelvic cavity. A needle biopsy of an abdominal wall lesion established it as a malignant tumor, origin unknown. Immunohistochemical staining post-surgery showed positive results for Cytokeratin (CK), CK7, Desmin, Vimentin, Caudal type homeobox 2 (CDX2), and Ki-67. Fluorescence in situ hybridization analysis revealed an Ewing sarcoma breakpoint region 1/EWS RNA binding protein 1 (EWSR1) rearrangement, and next-generation sequencing identified an EWSR1-Wilms tumor protein 1 (WT1) gene fusion.

INTERVENTIONS

The patient underwent laparoscopic exploratory surgery, which encompassed biopsy, ascites drainage, adhesion lysis, reinforcement of weakened sections of the small intestinal walls, and repositioning of twisted intestines. Postoperatively, the treatment protocol included fasting, rehydration, gastrointestinal decompression, and parenteral nutrition. However, the patient did not received chemotherapy.

OUTCOMES

The patient declined further treatment and deceased in early November.

LESSONS

This case highlights the nonspecific nature of DSRCT symptoms. In clinical practice, it is crucial to meticulously evaluate unexplained intestinal obstruction in young patients, considering DSRCT as a differential diagnosis to avoid delays in diagnosis.

Intraoperative Resection Guidance and Rapid Pathological Diagnosis of Osteosarcoma using B7H3 Targeted Probe under NIR-II Fluorescence Imaging

Complete removal of all tumor tissue with a wide surgical margin is essential for the treatment of osteosarcoma (OS). However, it's difficult, sometimes impossible, to achieve due to the invisible small satellite lesions and blurry tumor boundaries. Besides, intraoperative frozen-section analysis of resection margins of OS is often restricted by the hard tissues around OS, which makes it impossible to know whether a negative margin is achieved. Any unresected small tumor residuals will lead to local recurrence and worse prognosis. Herein, based on the high expression of B7H3 in OS, a targeted probe B7H3-IRDye800CW is synthesized by conjugating anti-B7H3 antibody and IRDye800CW. B7H3-IRDye800CW can accurately label OS areas after intravenous administration, thereby helping surgeons identify and resect residual OS lesions (<2 mm) and lung metastatic lesions. The tumor-background ratio reaches 4.42 ± 1.77 at day 3. After incubating fresh human OS specimen with B7H3-IRDye800CW, it can specifically label the OS area and even the microinvasion area (confirmed by hematoxylin-eosin [HE] staining). The probe labeled area is consistent with the tumor area shown by magnetic resonance imaging and complete HE staining of the specimen. In summary, B7H3-IRDye800CW has translational potential in intraoperative resection guidance and rapid pathological diagnosis of OS.

A promising target for breast cancer: B7-H3

Breast cancer (BC) is the second-leading factor of mortality for women globally and is brought on by a variety of genetic and environmental causes. The conventional treatments for this disease have limitations, making it difficult to improve the lifespan of breast cancer patients. As a result, extensive research has been conducted over the past decade to find innovative solutions to these challenges. Targeting of the antitumor immune response through the immunomodulatory checkpoint protein B7 family has revolutionized cancer treatment and led to intermittent patient responses. B7-H3 has recently received attention because of its significant demodulation and its immunomodulatory effects in many cancers. Uncontrolled B7-H3 expression and a bad outlook are strongly associated, according to a substantial body of cancer research. Numerous studies have shown that BC has significant B7-H3 expression, and B7-H3 induces an immune evasion phenotype, consequently enhancing the survival, proliferation, metastasis, and drug resistance of BC cells. Thus, an innovative target for immunotherapy against BC may be the B7-H3 checkpoint.In this review, we discuss the structure and regulation of B7-H3 and its double costimulatory/coinhibitory function within the framework of cancer and normal physiology. Then we expound the malignant behavior of B7-H3 in BC and its role in the tumor microenvironment (TME) and finally focus on targeted drugs against B7-H3 that have opened new therapeutic opportunities in BC.

Multifocal Desmoplastic Small Round Cell Tumor: A Case Report of a Rare Neoplasm

Desmoplastic small round cell tumor (DSRCT) is a rare, highly aggressive malignancy predominantly affecting adolescents and young adults. We report a case of multifocal DSRCT in an 11-year-old male who presented with complaints of unilateral forehead swelling, proptosis, and ophthalmoplegia for four months along with abdominal pain and dysphagia for six months. A whole-body computed tomography revealed widespread lesions in the skull, orbit, thorax, and abdomen with local infiltration. Ultrasound-guided biopsy of the forehead lump was performed. Based on histopathological and immunohistochemical investigations, it was diagnosed to be a DSRCT with multifocal presentation. The patient underwent chemo-radiation but unfortunately succumbed to neutropenic sepsis and renal failure. DSRCT is a very rare, highly aggressive malignancy with an extremely poor prognosis. Orbital presentations are even rarer, with less than 10 such cases currently described in English medical literature.

Evaluation of affinity matured Affibody molecules for imaging of the immune checkpoint protein B7-H3

B7-H3 (CD276), an immune checkpoint protein, is a promising molecular target for immune therapy of malignant tumours. Sufficient B7-H3 expression level is a precondition for successful therapy. Radionuclide molecular imaging is a powerful technique for visualization of expression levels of molecular targets in vivo. Use of small radiolabelled targeting proteins would enable high-contrast radionuclide imaging of molecular targets if adequate binding affinity and specificity of an imaging probe could be provided. Affibody molecules, small engineered affinity proteins based on a non-immunoglobulin scaffold, have demonstrated an appreciable potential in radionuclide imaging. Proof-of principle of radionuclide visualization of expression levels of B7-H3 in vivo was demonstrated using the [99mTc]Tc-AC12-GGGC Affibody molecule. We performed an affinity maturation of AC12, enabling selection of clones with higher affinity. Three most promising clones were expressed with a -GGGC (triglycine-cysteine) chelating sequence at the C-terminus and labelled with technetium-99m (99mTc). 99mTc-labelled conjugates bound to B7-H3-expressing cells specifically in vitro and in vivo. Biodistribution in mice bearing B7-H3-expressing SKOV-3 xenografts demonstrated improved imaging properties of the new conjugates compared with the parental variant [99mTc]Tc-AC12-GGGC. [99mTc]Tc-SYNT-179 provided the strongest improvement of tumour-to-organ ratios. Thus, affinity maturation of B7-H3 Affibody molecules could improve biodistribution and targeting properties for imaging of B7-H3-expressing tumours.

Global Impact of Monoclonal Antibodies (mAbs) in Children: A Focus on Anti-GD2

Monoclonal antibodies (mAbs), as the name implies, are clonal antibodies that bind to the same antigen. mAbs are broadly used as diagnostic or therapeutic tools for neoplasms, autoimmune diseases, allergic conditions, and infections. Although most mAbs are approved for treating adult cancers, few are applicable to childhood malignancies, limited mostly to hematological cancers. As for solid tumors, only anti-disialoganglioside (GD2) mAbs are approved specifically for neuroblastoma. Inequities of drug access have continued, affecting most therapeutic mAbs globally. To understand these challenges, a deeper dive into the complex transition from basic research to the clinic, or between marketing and regulatory agencies, is timely. This review focuses on current mAbs approved or under investigation in pediatric cancer, with special attention on solid tumors and anti-GD2 mAbs, and the hurdles that limit their broad global access. Beyond understanding the mechanisms of drug resistance, the continual discovery of next generation drugs safer for children and easier to administer, the discovery of predictive biomarkers to avoid futility should ease the acceptance by patient, health care professionals and regulatory agencies, in order to expand clinical utility. With a better integration into the multimodal treatment for each disease, protocols that align with the regional clinical practice should also improve acceptance and cost-effectiveness. Communication and collaboration between academic institutions, pharmaceutical companies, and regulatory agencies should help to ensure accessible, affordable, and sustainable health care for all.

Desmoplastic small round cell tumor: from state of the art to future clinical prospects

INTRODUCTION

Desmoplastic small round cell tumor (DSRCT) is an extremely rare and highly aggressive soft tissue sarcoma, presenting mainly in male adolescents and young adults with multiple nodules disseminated within the abdominopelvic cavity. Despite a multimodal approach including aggressive cytoreductive surgery, intensive multi-agent chemotherapy, and postoperative whole abdominopelvic radiotherapy, the prognosis for DSRCT remains dismal. Median progression-free survival ranges between 4 and 21 months, and overall survival between 17 and 60 months, with the 5-year overall survival rate in the range of 10-20%.

AREA COVERED

This review discusses the treatment strategies used for DSRCT over the years, the state of the art of current treatments, and future clinical prospects.

EXPERT OPINION

The unsatisfactory outcomes for patients with DSRCT warrant investigations into innovative treatment combinations. An international multidisciplinary and multi-stakeholder collaboration, involving both pediatric and adult sarcoma communities, is needed to propel preclinical model generation and drug development, and innovative clinical trial designs to enable the timely testing of treatments involving novel agents guided by biology to boost the chances of survival for patients with this devastating disease.

Recent advancements in the B7/CD28 immune checkpoint families: new biology and clinical therapeutic strategies

The B7/CD28 families of immune checkpoints play vital roles in negatively or positively regulating immune cells in homeostasis and various diseases. Recent basic and clinical studies have revealed novel biology of the B7/CD28 families and new therapeutics for cancer therapy. In this review, we discuss the newly discovered KIR3DL3/TMIGD2/HHLA2 pathways, PD-1/PD-L1 and B7-H3 as metabolic regulators, the glycobiology of PD-1/PD-L1, B7x (B7-H4) and B7-H3, and the recently characterized PD-L1/B7-1 cis-interaction. We also cover the tumor-intrinsic and -extrinsic resistance mechanisms to current anti-PD-1/PD-L1 and anti-CTLA-4 immunotherapies in clinical settings. Finally, we review new immunotherapies targeting B7-H3, B7x, PD-1/PD-L1, and CTLA-4 in current clinical trials.

Targeting B7-H3-A Novel Strategy for the Design of Anticancer Agents for Extracranial Pediatric Solid Tumors Treatment

Recent scientific data recognize the B7-H3 checkpoint molecule as a potential target for immunotherapy of pediatric solid tumors (PSTs). B7-H3 is highly expressed in extracranial PSTs such as neuroblastoma, rhabdomyosarcoma, nephroblastoma, osteosarcoma, and Ewing sarcoma, whereas its expression is absent or very low in normal tissues and organs. The influence of B7-H3 on the biological behavior of malignant solid neoplasms of childhood is expressed through different molecular mechanisms, including stimulation of immune evasion and tumor invasion, and cell-cycle disruption. It has been shown that B7-H3 knockdown decreased tumor cell proliferation and migration, suppressed tumor growth, and enhanced anti-tumor immune response in some pediatric solid cancers. Antibody-drug conjugates targeting B7-H3 exhibited profound anti-tumor effects against preclinical models of pediatric solid malignancies. Moreover, B7-H3-targeting chimeric antigen receptor (CAR)-T cells demonstrated significant in vivo activity against different xenograft models of neuroblastoma, Ewing sarcoma, and osteosarcoma. Finally, clinical studies demonstrated the potent anti-tumor activity of B7-H3-targeting antibody-radioimmunoconjugates in metastatic neuroblastoma. This review summarizes the established data from various PST-related studies, including in vitro, in vivo, and clinical research, and explains all the benefits and potential obstacles of targeting B7-H3 by novel immunotherapeutic agents designed to treat malignant extracranial solid tumors of childhood.

Identification of immunotherapy and radioimmunotherapy targets on desmoplastic small round cell tumors

Background

Development of successful antibody-based immunotherapeutic and radioimmunotherapeutic strategies rely on the identification of cell surface tumor-associated antigens (TAA) with restricted expression on normal tissues. Desmoplastic small round cell tumor (DSRCT) is a rare and generally neglected malignancy that primarily affects adolescent and young adult males. New therapies capable of treating disseminated disease are needed for DSRCT, which is often widespread at diagnosis.

Methods

We used immunohistochemistry (IHC) on fresh frozen surgical specimens and patient-derived xenograft (PDX) tumors and flow cytometry on DSRCT cell lines to evaluate expression of TAAs in these tumors. In vitro cytotoxicity assays were used to evaluate the efficacy of T cell-engaging bispecific antibodies (T-BsAbs) directed at these targets. In vivo, we used an intraperitoneal xenograft mouse model of DSRCT to test T-BsAbs against several TAAs.

Results

In DSRCT specimens we found widespread expression of B7-H3, EGFR, GD2, HER2, mesothelin, and polysialic acid, clinical targets for which specific antibody therapeutics are available. The expression of B7-H3, EGFR, HER2, and mesothelin was confirmed on the cell surface of DSRCT cell lines. In vitro cytotoxicity assays confirmed the efficacy of T cell-engaging bispecific antibodies (T-BsAbs) directed at these targets against DSRCT cells. Remarkably, a HER2xCD3 T-BsAb was capable of completely shrinking established tumors in an intraperitoneal mouse model of DSRCT.

Conclusions

We propose that these TAAs should be further investigated in preclinical models as targets for immunotherapy and radioimmunotherapy with the hope of providing a rationale to extend these therapies to patients with advanced DSRCT.

Molecular profiling in desmoplastic small round cell tumours

Desmoplastic small round cell tumour (DSRCT) is an ultra-rare soft tissue sarcoma that is characterised by aggressive disease and dismal patient outcomes. Despite multi-modal therapy, prognosis remains poor and there are currently no effective targeted therapies available for patients with this disease. Advances in comprehensive molecular profiling approaches including next generation sequencing and proteomics hold the promise of identifying new therapeutic targets and biomarkers. In this review, we provide an overview of the current status of molecular profiling studies in DSRCT patient specimens and cell lines, highlighting the key genomic, epigenetic and proteomic findings that have contributed to our biological knowledge base of this recalcitrant disease. In-depth analysis of these molecular profiles has led to the identification of promising novel and repurposed candidate therapies that are suitable for translation into clinical trials. We further provide a perspective on how future integrated studies including proteogenomics could further enrich our understanding of this ultra-rare entity and deliver progress that will ultimately impact the outcomes of patients with DSRCT.

Nanomedicine embraces cancer radio-immunotherapy: mechanism, design, recent advances, and clinical translation

Cancer radio-immunotherapy, integrating external/internal radiation therapy with immuno-oncology treatments, emerges in the current management of cancer. A growing number of pre-clinical studies and clinical trials have recently validated the synergistic antitumor effect of radio-immunotherapy, far beyond the "abscopal effect", but it suffers from a low response rate and toxicity issues. To this end, nanomedicines with an optimized design have been introduced to improve cancer radio-immunotherapy. Specifically, these nanomedicines are elegantly prepared by incorporating tumor antigens, immuno- or radio-regulators, or biomarker-specific imaging agents into the corresponding optimized nanoformulations. Moreover, they contribute to inducing various biological effects, such as generating in situ vaccination, promoting immunogenic cell death, overcoming radiation resistance, reversing immunosuppression, as well as pre-stratifying patients and assessing therapeutic response or therapy-induced toxicity. Overall, this review aims to provide a comprehensive landscape of nanomedicine-assisted radio-immunotherapy. The underlying working principles and the corresponding design strategies for these nanomedicines are elaborated by following the concept of "from bench to clinic". Their state-of-the-art applications, concerns over their clinical translation, along with perspectives are covered.

Phase 1 study of intraventricular 131I-omburtamab targeting B7H3 (CD276)-expressing CNS malignancies

BACKGROUND

The prognosis for metastatic and recurrent tumors of the central nervous system (CNS) remains dismal, and the need for newer therapeutic targets and modalities is critical. The cell surface glycoprotein B7H3 is expressed on a range of solid tumors with a restricted expression on normal tissues. We hypothesized that compartmental radioimmunotherapy (cRIT) with the anti-B7H3 murine monoclonal antibody omburtamab injected intraventricularly could safely target CNS malignancies.

PATIENTS AND METHODS

We conducted a phase I trial of intraventricular ¹³¹I-omburtamab using a standard 3 + 3 design. Eligibility criteria included adequate cerebrospinal fluid (CSF) flow, no major organ toxicity, and for patients > dose level 6, availability of autologous stem cells. Patients initially received 74 MBq radioiodinated omburtamab to evaluate dosimetry and biodistribution followed by therapeutic ¹³¹I-omburtamab dose-escalated from 370 to 2960 MBq. Patients were monitored clinically and biochemically for toxicity graded using CTCAEv 3.0. Dosimetry was evaluated using serial CSF and blood sampling, and serial PET or gamma-camera scans. Patients could receive a second cycle in the absence of grade 3/4 non-hematologic toxicity or progressive disease.

RESULTS

Thirty-eight patients received 100 radioiodinated omburtamab injections. Diagnoses included metastatic neuroblastoma (n = 16) and other B7H3-expressing solid tumors (n = 22). Thirty-five patients received at least 1 cycle of treatment with both dosimetry and therapy doses. Acute toxicities included < grade 4 self-limited headache, vomiting or fever, and biochemical abnormalities. Grade 3/4 thrombocytopenia was the most common hematologic toxicity. Recommended phase 2 dose was 1850 MBq/injection. The median radiation dose to the CSF and blood by sampling was 1.01 and 0.04 mGy/MBq, respectively, showing a consistently high therapeutic advantage for CSF. Major organ exposure was well below maximum tolerated levels. In patients developing antidrug antibodies, blood clearance, and therefore therapeutic index, was significantly increased. In patients receiving cRIT for neuroblastoma, survival was markedly increased (median PFS 7.5 years) compared to historical data.

CONCLUSIONS

cRIT with ¹³¹I-omburtamab is safe, has favorable dosimetry and may have a therapeutic benefit as adjuvant therapy for B7-H3-expressing leptomeningeal metastases.

TRIAL REGISTRATION

clinicaltrials.gov NCT00089245, August 5, 2004.

Immune checkpoint of B7-H3 in cancer: from immunology to clinical immunotherapy

Immunotherapy for cancer is a rapidly developing treatment that modifies the immune system and enhances the antitumor immune response. B7-H3 (CD276), a member of the B7 family that plays an immunoregulatory role in the T cell response, has been highlighted as a novel potential target for cancer immunotherapy. B7-H3 has been shown to play an inhibitory role in T cell activation and proliferation, participate in tumor immune evasion and influence both the immune response and tumor behavior through different signaling pathways. B7-H3 expression has been found to be aberrantly upregulated in many different cancer types, and an association between B7-H3 expression and poor prognosis has been established. Immunotherapy targeting B7-H3 through different approaches has been developing rapidly, and many ongoing clinical trials are exploring the safety and efficacy profiles of these therapies in cancer. In this review, we summarize the emerging research on the function and underlying pathways of B7-H3, the expression and roles of B7-H3 in different cancer types, and the advances in B7-H3-targeted therapy. Considering different tumor microenvironment characteristics and results from preclinical models to clinical practice, the research indicates that B7-H3 is a promising target for future immunotherapy, which might eventually contribute to an improvement in cancer immunotherapy that will benefit patients.

Advances in the treatment of pediatric solid tumors: A 50-year perspective

In the United States, more than 10 000 cancers occur annually in children aged 0-14 years, and more than 5000 in adolescents aged 15-19. In the last 50 years, significant advances have been made in imaging, molecular pathology, stage and risk assessment, surgical approach, multidisciplinary treatment, and survival for pediatric solid tumors (particularly neuroblastoma, Wilms tumor, rhabdomyosarcoma, and hepatoblastoma). Moreover, the molecular driver for fibrolamellar hepatocellular carcinoma, which occurs in adolescence and young adulthood, has been identified.

Bispecific antibodies for the treatment of neuroblastoma

Bispecific antibodies (BsAb) are a new generation of antibody-based therapy, conveying artificial specificity to polyclonal T cells or radiohaptens. These drugs have been successfully implemented to cure hematologic malignancies and are under clinical investigation for solid tumors including HRNB. BsAbs designed to engage T cells or increase the therapeutic index of radiotherapy hold the potential to significantly improve the long-term survival of HRNB patients by shrinking bulky tumors and more effectively eliminating micrometastases and preventing relapse. BsAbs can also be used to arm T cells, yielding a product analogous to CAR T cells, possibly with an improved safety profile. A thoughtful and realistic integration of these therapies into the standard of care should benefit more patients worldwide. Here we describe the history of development of BsAbs for HRNB, which dates back almost three decades. We discuss the merits and pitfalls of all relevant BsAbs, including T cell-engagers and agents used for radioimmunotherapy, highlighting the importance of structural design and interdomain spacing for anti-tumor efficacy.

Peritoneal carcinomatosis with intraperitoneal immunotherapy: current treatment options and perspectives

INTRODUCTION

Peritoneal carcinomatosis (PC) is an advanced malignancy that is not sensitive to systemic conventional chemotherapy. Treatment options for PC are usually palliative rather than curative. Cytoreductive surgery and hyperthermic intraperitoneal (IP) chemotherapy are associated with limited efficacy in patients with PC. However, the peritoneum can produce effective immunity by inducing T-lymphocyte recruitment and proliferation, and the unique immune environment of the peritoneum provides the rationale for IP immunotherapy in PC.

AREAS COVERED

The authors retrieved relevant documents of IP immunotherapy for PC from PubMed and Medline. This review elaborates on the knowledge of the peritoneal immune microenvironment and IP immunotherapy for PC covering immune stimulators, radioimmunotherapy, catumaxomab, cancer vaccines, chimeric antigen receptor (CAR)-T cells, and immune checkpoint inhibitors.

EXPERT OPINION

The prognosis of PC is poor. However, the peritoneal cavity is a unique immune compartment with abundant immune cells which can produce effective immunity. IP immunotherapy may be a promising strategy in patients with PC.

Evaluation of an Affibody-Based Binder for Imaging of Immune Check-Point Molecule B7-H3

Radionuclide molecular imaging could provide an accurate assessment of the expression of molecular targets in disseminated cancers enabling stratification of patients for specific therapies. B7-H3 (CD276) is a transmembrane protein belonging to the B7 superfamily. This protein is overexpressed in different types of human malignancies and such upregulation is generally associated with a poor clinical prognosis. In this study, targeting properties of an Affibody-based probe, AC12, containing a -GGGC amino acid sequence as a chelator (designated as AC12-GGGC) labelled with technetium-99m (99mTc) were evaluated for imaging of B7-H3-expressing tumours. AC12-GGGC was efficiently labelled with 99mTc. [99mTc]Tc-AC12-GGGC bound specifically to B7-H3 expressing cells in vitro with affinities in nanomolar range. In mice bearing B7-H3-expressing xenografts, [99mTc]Tc-AC12-GGGC showed tumour uptake of 2.1 ± 0.5 %ID/g at 2 h after injection. Its clearance from blood, normal organs and tissues was very rapid. This new targeting agent, [99mTc]Tc-AC12-GGGC, provided high tumour-to-blood ratio already at 2 h (8.2 ± 1.9), which increased to 11.0 ± 0.5 at 4 h after injection. Significantly (p < 0.05) higher tumour-to-liver and higher tumour-to-bone ratios at 2 h in comparison with 4 h after injection were observed. Thus, [99mTc]Tc-AC12-GGGC could be a promising candidate for further development.

Chimeric Antigen Receptor (CAR)-T Cell Immunotherapy Against Thoracic Malignancies: Challenges and Opportunities

Different from surgery, chemical therapy, radio-therapy and target therapy, Chimeric antigen receptor-modified T (CAR-T) cells, a novel adoptive immunotherapy strategy, have been used successfully against both hematological tumors and solid tumors. Although several problems have reduced engineered CAR-T cell therapeutic outcomes in clinical trials for the treatment of thoracic malignancies, including the lack of specific antigens, an immunosuppressive tumor microenvironment, a low level of CAR-T cell infiltration into tumor tissues, off-target toxicity, and other safety issues, CAR-T cell treatment is still full of bright future. In this review, we outline the basic structure and characteristics of CAR-T cells among different period, summarize the common tumor-associated antigens in clinical trials of CAR-T cell therapy for thoracic malignancies, and point out the current challenges and new strategies, aiming to provide new ideas and approaches for preclinical experiments and clinical trials of CAR-T cell therapy for thoracic malignancies.

Biodistribution and Radiation Dosimetry of Intraperitoneally Administered 124I-Omburtamab in Patients with Desmoplastic Small Round Cell Tumors

The aim of this study was to assess the pharmacokinetics, biodistribution, and radiation dosimetry of ¹²⁴I-omburtamab administered intraperitoneally in patients with desmoplastic small round cell tumor. Methods: Eligible patients diagnosed with desmoplastic small round cell tumor with peritoneal involvement were enrolled in a phase I trial of intraperitoneal radioimmunotherapy with ¹³¹I-omburtamab. After thyroid blockade and before radioimmunotherapy, patients received approximately 74 MBq of ¹²⁴I-omburtamab intraperitoneally. Five serial PET/CT scans were obtained up to 144 h after injection. Multiple blood samples were obtained up to 120 h after injection. Organ-absorbed doses were calculated with OLINDA/EXM. Results: Thirty-one patients were studied. Blood pharmacokinetics exhibited a biphasic pattern consisting of an initial rising phase with a median half-time (±SD) of 23 ± 15 h and a subsequent falling phase with a median half-time of 56 ± 34 h. Peritoneal distribution was heterogeneous and diffuse in most patients. Self-dose to the peritoneal cavity was 0.58 ± 0.19 mGy/MBq. Systemic distribution and activity in major organs were low. The median absorbed doses were 0.72 ± 0.23 mGy/MBq for liver, 0.48 ± 0.17 mGy/MBq for spleen, and 0.57 ± 0.12 mGy/MBq for kidneys. The mean effective dose was 0.31 ± 0.10 mSv/MBq. Whole-body and peritoneal cavity biologic half-times were 45 ± 9 and 24 ± 5 h, respectively. Conclusion: PET/CT imaging with intraperitoneally administered ¹²⁴I-omburtamab enables assessment of intraperitoneal distribution and estimation of absorbed dose to peritoneal space and normal organs before therapy.

Insights on recent innovations in bladder cancer immunotherapy

Bladder carcinoma is the most common genitourinary cancer, with a high prevalence and global incidence. In addition to early detection by cytology, the management of bladder cancer has recently advanced, not only by improvements in conventional treatments such as surgery and chemotherapy, but also through the introduction of immunotherapeutic strategies. The number of approved immunotherapeutic agents has dramatically increased, with various preclinical and clinical applications in cancer drug discovery. Some bladder cancer immunotherapies include immune checkpoint inhibitors, adoptive cell therapy, cytokine-based therapy, bispecific antibodies, and antibody-drug conjugates. This review provides an overview of some of the innovative immunotherapeutic agents approved and in development that can potentially be used in the treatment of bladder cancer.

Genome-scale CRISPR-Cas9 screen reveals novel regulators of B7-H3 in tumor cells

Background

Despite advances in B7 homolog 3 protein (B7-H3) based immunotherapy, the development of drug resistance remains a major clinical concern. The heterogeneity and emerging loss of B7-H3 expression are the main causes of drug resistance and treatment failure in targeted therapies, which reveals an urgent need to elucidate the mechanism underlying the regulation of B7-H3 expression. In this study, we identified and explored the crucial role of the transcription factor SPT20 homolog (SP20H) in B7-H3 expression and tumor progression.

Methods

Here, we performed CRISPR/Cas9-based genome scale loss-of-function screening to identify regulators of B7-H3 in human ovarian cancer cells. Signaling pathways altered by SP20H knockout were revealed by RNA sequencing. The regulatory role and mechanism of SP20H in B7-H3 expression were validated using loss-of-function and gain-of-function assays in vitro. The effects of inhibiting SP20H on tumor growth and efficacy of anti-B7-H3 treatment were evaluated in tumor-bearing mice.

Results

We identified SUPT20H (SP20H) as negative and eIF4E as positive regulators of B7-H3 expression in various cancer cells. Furthermore, we provided evidence that either SP20H loss or TNF-α stimulation in tumor cells constitutively activates p38 MAPK-eIF4E signaling, thereby upregulating B7-H3 expression. Loss of SP20H upregulated B7-H3 expression both in vitro and in vivo. Additionally, deletion of SP20H significantly suppressed tumor growth and increased immune cells infiltration in tumor microenvironment. More importantly, antibody–drug conjugates targeting B7-H3 exhibited superior antitumor performance against SP20H-deficient tumors relative to control groups.

Conclusions

Activation of p38 MAPK-eIF4E signaling serves as a key event in the transcription initiation and B7-H3 protein expression in tumor cells. Genetically targeting SP20H upregulates target antigen expression and sensitizes tumors to anti-B7-H3 treatment. Collectively, our findings provide new insight into the mechanisms underlying B7-H3 expression and introduce a potential synergistic target for existing antibody-based targeted therapy against B7-H3.

Ewing sarcoma and related FET family translocation-associated round cell tumors: a century of clinical and scientific progress

The year 2021 marked the centenary of the first publication of a cancer termed diffuse endothelioma of bone by James Ewing. Its unique features were apparent even in the first case series he described. This new diagnosis was clearly distinct from osteogenic sarcoma and myeloma, which were already well recognized at the time. We undertake this summary to better understanding Ewing sarcoma, contrasting the logarithmic evolution of the standard of care of systemic therapy for this and related diagnoses to the exponential understanding of the molecular biology of this family of tumors. We also outline in this manuscript how the finding of genomic relatives within Ewing sarcoma itself and related tumors, first noted nearly 40 years ago, helps us appreciate the need to find therapeutic plans that are specific for each small round blue cell tumor subtype. The advent of next generation sequencing regarding previously unknown small round blue cell tumor subtypes in many ways puts us back in the shoes of James Ewing in 1921, searching anew for clues leading to better treatments for increasingly rare cancer subsets. This article is protected by copyright. All rights reserved.

Intraperitoneal Pretargeted Radioimmunotherapy for Colorectal Peritoneal Carcinomatosis

Peritoneal carcinomatosis (PC) is considered incurable, and more effective therapies are needed. Herein we test the hypothesis that GPA33-directed intracompartmental pretargeted radioimmunotherapy (PRIT) can cure colorectal peritoneal carcinomatosis. Nude mice were implanted intraperitoneally with luciferase-transduced GPA33-expressing SW1222 cells for aggressive peritoneal carcinomatosis (e.g., resected tumor mass 0.369 ± 0.246 g; n = 17 on day 29). For GPA33-PRIT, we administered intraperitoneally a high-affinity anti-GPA33/anti-DOTA bispecific antibody (BsAb), followed by clearing agent (intravenous), and lutetium-177 (Lu-177) or yttrium-86 (Y-86) radiolabeled DOTA-radiohapten (intraperitoneal) for beta/gamma-emitter therapy and PET imaging, respectively. The DOTA-radiohaptens were prepared from S-2-(4-aminobenzyl)-1,4,7, 10-tetraazacyclododecane tetraacetic acid chelate (DOTA-Bn). Efficacy and toxicity of single- versus three-cycle therapy were evaluated in mice 26-27 days post-tumor implantation. Single-cycle treatment ([177Lu]LuDOTA-Bn 111 MBq; tumor dose: 4,992 cGy) significantly prolonged median survival (MS) approximately 2-fold to 84.5 days in comparison with controls (P = 0.007). With three-cycle therapy (once weekly, total 333 MBq; tumor dose: 14,975 cGy), 6/8 (75%) survived long-term (MS > 183 days). Furthermore, for these treated long-term survivors, 1 mouse was completely disease free (microscopic "cure") at necropsy; the others showed stabilized disease, which was detectable during PET-CT using [86Y]DOTA-Bn. Treatment controls had MS ranging from 42-52.5 days (P < 0.001) and 19/20 mice succumbed to progressive intraperitoneal disease by 69 days. Multi-cycle GPA33 DOTA-PRIT significantly prolongs survival with reversible myelosuppression and no chronic marrow (929 cGy to blood) or kidney (982 cGy) radiotoxicity, with therapeutic indices of 12 for blood and 12 for kidneys. MTD was not reached.

Immunotherapies for Pediatric Solid Tumors: A Targeted Update

There are encouraging signs in our collective progress to leverage the immune system to treat pediatric cancers. Here, we summarize interim successes in cancer immunotherapy and opportunities to translate from the adult world to pediatrics, and highlight challenges that could benefit from additional development, focusing on solid tumors. Just a decade ago, other than antibodies targeting disialoganglioside (GD2) in neuroblastoma, pediatric cancer immunotherapy was mostly relegated to obscure preclinical studies in a few academic labs. Today there are numerous clinical trials of a variety of antibody, cellular, gene, and viral therapies and vaccines designed to either promote antitumor immunity or specifically attack validated immunotherapy targets. Understanding those targets and their pediatric relevance is paramount. While much work is underway to evaluate the utility of numerous immunologic targets, the lack of regulatory approvals is emblematic of the challenges that remain. Herein we focus our review on the most promising targeted immunotherapies in clinical trials for children.

B7-H3 Suppresses Antitumor Immunity via the CCL2-CCR2-M2 Macrophage Axis and Contributes to Ovarian Cancer Progression

New approaches beyond PD-1/PD-L1 inhibition are required to target the immunologically diverse tumor microenvironment (TME) in high-grade serous ovarian cancer (HGSOC). In this study, we explored the immunosuppressive effect of B7-H3 (CD276) via the CCL2-CCR2-M2 macrophage axis and its potential as a therapeutic target. Transcriptome analysis revealed that B7-H3 is highly expressed in PD-L1-low, nonimmunoreactive HGSOC tumors, and its expression negatively correlated with an IFNγ signature, which reflects the tumor immune reactivity. In syngeneic mouse models, B7-H3 (Cd276) knockout (KO) in tumor cells, but not in stromal cells, suppressed tumor progression, with a reduced number of M2 macrophages and an increased number of IFNγ⁺CD8⁺ T cells. CCL2 expression was downregulated in the B7-H3 KO tumor cell lines. Inhibition of the CCL2-CCR2 axis partly negated the effects of B7-H3 suppression on M2 macrophage migration and differentiation, and tumor progression. In patients with HGSOC, B7-H3 expression positively correlated with CCL2 expression and M2 macrophage abundance, and patients with B7-H3-high tumors had fewer tumoral IFNγ⁺CD8⁺ T cells and poorer prognosis than patients with B7-H3-low tumors. Thus, B7-H3 expression in tumor cells contributes to CCL2-CCR2-M2 macrophage axis-mediated immunosuppression and tumor progression. These findings provide new insights into the immunologic TME and could aid the development of new therapeutic approaches against the unfavorable HGSOC phenotype.

Immunotherapy and Radioimmunotherapy for Desmoplastic Small Round Cell Tumor

Desmoplastic small round cell tumor (DRSCT) is a highly aggressive primitive sarcoma that primarily affects adolescent and young adult males. The 5-year survival rate is 15-30% and few curative treatment options exist. Although there is no standard treatment for DSRCT, patients are most often treated with a combination of aggressive chemotherapy, radiation, and surgery. Targeted therapy inhibitors of PDGFA and IGF-1R, which are almost uniformly overexpressed in DSRCT, have largely failed in clinical trials. As in cancer in general, interest in immunotherapy to treat DSRCT has increased in recent years. To that end, several types of immunotherapy are now being tested clinically, including monoclonal antibodies, radionuclide-conjugated antibodies, chimeric antigen receptor T cells, checkpoint inhibitors, and bispecific antibodies (BsAbs). These types of therapies may be particularly useful in DSRCT, which is frequently characterized by widespread intraperitoneal implants, which are difficult to completely remove surgically and are the frequent cause of relapse. Successful treatment with immunotherapy or radioimmunotherapy following debulking surgery could eradiate these micrometasteses and prevent relapse. Although there has been limited success to date for immunotherapy in pediatric solid tumors, the significant improvements in survival seen in the treatment of other pediatric solid tumors, such as metastatic neuroblastoma and its CNS spread, suggest a potential of immunotherapy and specifically compartmental immunotherapy in DSRCT.

Radioimmunotherapy in Oncology: Overview of the Last Decade Clinical Trials

Simple Summary

Monoclonal antibody-bearing radionuclides have been under clinical investigation over the last two decades for their use in theranostic (diagnostic and therapeutic) applications in cancer. However, despite the numerous trials that have been conducted, only two radioimmunotherapies (RIT) have been approved by the FDA for the targeted therapy of hematologic tumors expressing CD20 antigens. Moreover, RIT applications for solid cancers faced major issues—such as radiotoxicity due to low antibodies penetrance requiring substantial curative dose—where new discoveries concerning antibody engineering or radionuclides are trying to overcome. Here, we performed an overview of the last 11-year clinical trials involving RIT for solid and non-solid cancers conducted either with full antibodies or antibody fragments. We discussed the low-to-moderate efficiency of RIT compared to conventional therapies and described the last advances in clinic for antibodies carriers (F(ab′)₂, Fab′, ScFv). Finally, we discussed about the complexity of RIT as a therapy and depicted both the issues and the prospects of such a strategy.

Abstract

The specific irradiation of tumors with selective radiolabeled antibodies constitutes an attractive therapeutic approach. Consequent preclinical research has been conducted by both biologists to identify pertinent targets and to select corresponding antibodies (mAb) and by radiochemists to radiolabel mAbs. These numerous preclinical investigations have ascertained the therapeutic interest of radioimmunotherapy (RIT) protocols in mice models. Here, we summarize the clinical studies that have been performed the last decade, including clinical trials (phases I, II, and III), prospective and retrospective studies, and cases series. We thereby reported 92 clinical studies. Among them, 62 concern the treatment of hematological malignancies, and 30 concern solid tumors. For hematologic diseases, the analysis was complex due to the high discrepancy of therapeutic strategies (first-line therapy, consolidation, stem cell transplantation conditioning) as well as the high variety of malignancies that were treated. The clinical studies from the last decade failed to expand anti-CD20 RIT indications but confirmed that RIT using radiolabeled anti-CD20 remains a pertinent choice for patients with relapse follicular lymphomas. For solid tumors, the positive benefit of RIT is more mitigated, apart for few malignancies that can be treated locally. Clinical trials also demonstrated the potential of some antibody formats, such as F(ab′)₂, which has already been approved by the China State FDA under the trend name Licartin®. Despite disparate results, mAb fragments are an interesting prospect for the improvement of RIT efficiency as well as for pretargeted strategies that delay the injection of radioactive treatments from the mAb ones.

Radioimmunotherapy for solid tumors: spotlight on Glypican-1 as a radioimmunotherapy target

Radioimmunotherapy (i.e., the use of radiolabeled tumor targeting antibodies) is an emerging approach for the diagnosis, therapy, and monitoring of solid tumors. Often using paired agents, each targeting the same tumor molecule, but labelled with an imaging or therapeutic isotope, radioimmunotherapy has achieved promising clinical results in relatively radio-resistant solid tumors such as prostate. Several approaches to optimize therapeutic efficacy, such as dose fractionation and personalized dosimetry, have seen clinical success. The clinical use and optimization of a radioimmunotherapy approach is, in part, influenced by the targeted tumor antigen, several of which have been proposed for different solid tumors. Glypican-1 (GPC-1) is a heparan sulfate proteoglycan that is expressed in a variety of solid tumors, but whose expression is restricted in normal adult tissue. Here, we discuss the preclinical and clinical evidence for the potential of GPC-1 as a radioimmunotherapy target. We describe the current treatment paradigm for several solid tumors expressing GPC-1 and suggest the potential clinical utility of a GPC-1 directed radioimmunotherapy for these tumors.

Intra-Abdominal Desmoplastic Small Round Cell Tumor: Current Treatment Options and Perspectives

Intra-abdominal desmoplastic small round cell tumor (IDSRCT) is a rare and highly malignant soft tissue neoplasm, which is characterized by rapid progression and poor prognosis. The mechanism underlying the development of this neoplasm remains elusive, but all cases are characterized by the chromosomal translocation t (11;22) (p13; q12), which results in a formation of EWSR1-WT1 gene fusion. The diagnosis of IDSRCT is often made with core-needle tissue biopsy specimens or laparoscopy or laparotomy. Immunohistochemical analyses have shown the co-expression of epithelial, neuronal, myogenic, and mesenchymal differentiation markers. FISH or reverse transcription polymerase chain reaction detecting EWS-WT1 fusion can be performed to assist in molecular confirmation. There is no standard of care for patients with IDSRCT currently, and majority of newly diagnosed patients received the aggressive therapy, which includes >90% resection of surgical debulking, high-dose alkylator-based chemotherapy, and radiotherapy. More recently, targeted therapy has been increasingly administered to recurrent IDSRCT patients and has been associated with improved survival in clinical conditions. Immunotherapy as a possible therapeutic strategy is being explored in patients with IDSRCT. In this review, we summarize currently available knowledge regarding the epidemiology, potential mechanisms, clinical manifestations, diagnosis, treatment, and prognosis of IDSRCT to assist oncologists in comprehensively recognizing and accurately treating this malignancy.

Effective killing of cells expressing CD276 (B7-H3) by a bispecific T cell engager based on a new fully human antibody

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A new fully human antibody, B11, that specifically targets CD276 was identified.

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The epitope of B11 is the V1/V2 domain of CD276 and it competes with the antibody 8H9 (Omburtamab).

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B11-BiTE mediates strong T cell cytotoxicity to 14 different tumor cell lines.

The pancaner molecule CD276 (B7-H3) is an attractive target for antibody based therapy. We identified from a large (10¹¹) phage-displayed single-chain variable fragment (scFv) library, a fully human antibody, B11, which bound with high avidity (K_D=0.4 nM) to CD276. B11 specifically bound to the V1/V2 domain of CD276 and competed with the antibody 8H9 (Omburtamab). It was used to design an IgG-format bispecific T cell engager B11-BiTE, which was more effective than 8H9-BiTE in 14 different cancer cell lines. B11-BiTE also exhibited strong ADCC/ADCP. Therefore, the fully human B11-BiTE is a promising candidate for treatment of tumors expressing CD276.

Co-immunizing with HMGB1 enhances anti-tumor immunity of B7H3 vaccine in renal carcinoma

Metastatic renal carcinoma is a kind of tumor with high degree of malignancy, but there are no effective treatment methods and strategies at present. In this study, we designed a folate-grafted PEI600-CyD (H1) nanoparticle-mediated DNA vaccine containing an adjuvant of high mobility group box 1 protein (HMGB1) and a tumor-specific antigen of B7H3 (CD276) for renal carcinoma therapy. Mice bearing subcutaneous human B7H3 (hB7H3)-Renca tumor were immunized with H1-pHMGB1/pB7H3, H1-pB7H3, H1-pHMGB1, or Mock vaccine. Compared to other control groups, the growth of the tumor was significantly inhibited in H1-pHMGB1/pB7H3 vaccine group. The increased proportion and mature of CD11c⁺ DCs were observed in the spleen of H1-pHMGB1/pB7H3 treated mice. Likewise, HMGB1 promoted B7H3 vaccine to induce tumor-specific CD8⁺ T cell proliferation and CTL responses. Beyond that, H1-pHMGB1/pB7H3 vaccine strengthened the induction of functional CD8⁺ T cells. With the depletion of CD8⁺ T cells, the anti-tumor effect of H1-pHMGB1/pB7H3 also disappeared, indicating that CD8⁺ T cells are the key factor of the anti-tumor activity of the vaccine. So, to sum up, H1-pHMGB1/pB7H3 vaccine could achieve the desired anti-tumor effect by enhancing the response of tumor-specific functional CD8⁺ T cell responses. H1 nanoparticle-based vaccines may have great potential and prospect in the treatment of primary solid tumors.

Antibody Conjugates for Sarcoma Therapy: How Far along Are We?

Sarcomas are one of the most difficult type of cancer to manage and treat because of their extremely heterogeneous molecular and morphological features. Despite the progress made over the years in the establishment of standard protocols for high and low grading/staging sarcoma patients, mostly with chemotherapy and/or radiotherapy, 50% of treated patients experience relapse episodes. Because of this, in the last 20 years, new therapeutic approaches for sarcoma treatment have been evaluated in preclinical and clinical studies. Among them, antibody-based therapies have been the most studied. Immunoconjugates consist of a carrier portion, frequently represented by an antibody, linked to a toxic moiety, i.e., a drug, toxin, or radionuclide. While the efficacy of immunoconjugates is well demonstrated in the therapy of hematological tumors and more recently also of epithelial ones, their potential as therapeutic agents against sarcomas is still not completely explored. In this paper, we summarize the results obtained with immunoconjugates targeting sarcoma surface antigens, considering both preclinical and clinical studies. To date, the encouraging results obtained in preclinical studies allowed nine immunoconjugates to enter clinical trials, demonstrating the validity of immunotherapy as a promising pharmacological tool also for sarcoma therapy.

FUT8-mediated aberrant N-glycosylation of B7H3 suppresses the immune response in triple-negative breast cancer

Most patients with triple negative breast cancer (TNBC) do not respond to anti-PD1/PDL1 immunotherapy, indicating the necessity to explore immune checkpoint targets. B7H3 is a highly glycosylated protein. However, the mechanisms of B7H3 glycosylation regulation and whether the sugar moiety contributes to immunosuppression are unclear. Here, we identify aberrant B7H3 glycosylation and show that N-glycosylation of B7H3 at NXT motif sites is responsible for its protein stability and immunosuppression in TNBC tumors. The fucosyltransferase FUT8 catalyzes B7H3 core fucosylation at N-glycans to maintain its high expression. Knockdown of FUT8 rescues glycosylated B7H3-mediated immunosuppressive function in TNBC cells. Abnormal B7H3 glycosylation mediated by FUT8 overexpression can be physiologically important and clinically relevant in patients with TNBC. Notably, the combination of core fucosylation inhibitor 2F-Fuc and anti-PDL1 results in enhanced therapeutic efficacy in B7H3-positive TNBC tumors. These findings suggest that targeting the FUT8-B7H3 axis might be a promising strategy for improving anti-tumor immune responses in patients with TNBC.

Desmoplastic Small Round Cell Tumor: A Review of Main Molecular Abnormalities and Emerging Therapy

Simple Summary

Desmoplastic small round cell tumor is a rare neoplasm with extremely aggressive behavior. Despite the multimodal treatment for newly diagnosed patients with chemotherapy, cytoreductive surgery and radiation, the cure rate is still low. For relapsed or progressive disease, there is limited data regarding second and third-line therapies. Novel agents have shown only modest activity. Recent molecular changes have been identified in this disease and this opens opportunities to be explored in future clinical trials.

Abstract

Desmoplastic small round cell tumor (DSRCT) is an extremely rare, aggressive sarcoma affecting adolescents and young adults with male predominance. Generally, it originates from the serosal surface of the abdominal cavity. The hallmark characteristic of DSRCT is the EWSR1–WT1 gene fusion. This translocation up-regulates the expression of PDGFRα, VEGF and other proteins related to tumor and vascular cell proliferation. Current management of DSRCT includes a combination of chemotherapy, radiation and aggressive cytoreductive surgery plus intra-peritoneal hyperthermic chemotherapy (HIPEC). Despite advances in multimodal therapy, outcomes remain poor since the majority of patients present disease recurrence and die within three years. The dismal survival makes DSRCT an orphan disease with an urgent need for new drugs. The treatment of advanced and recurrent disease with tyrosine kinase inhibitors, such as pazopanib, sunitinib, and mTOR inhibitors was evaluated by small trials. Recent studies using comprehensive molecular profiling of DSRCT identified potential therapeutic targets. In this review, we aim to describe the current studies conducted to better understand DSRCT biology and to explore the new therapeutic strategies under investigation in preclinical models and in early phase clinical trials.