Randomized Phase III Trial of Ganitumab With Interval-Compressed Chemotherapy for Patients With Newly Diagnosed Metastatic Ewing Sarcoma: A Report From the Children's Oncology Group

Consensus recommendations regarding local and metastasis-directed therapies in the management of relapsed/recurrent Ewing sarcoma

Limited randomized or prospective data are available to guide local/metastasis directed therapy (LMDT) in relapsed/recurrent Ewing sarcoma (RR-ES), resulting in uncertainty regarding best clinical practice for these patients. This report reviews the available literature on LMDT approaches and provides consensus recommendations regarding therapeutic decision making, timing, and indications for the use of LMDT in the management of RR-ES. LMDT should be considered on a case-by-case basis to assess appropriateness, optimal timing/modality, palliative versus curative intent, and its role in relation to chemotherapy. One commonly used LMDT is radiotherapy (RT), which can be delivered through standard, hypofractionated, or stereotactic techniques based on factors including prior RT, tumor size, and/or location. Chemotherapy can be combined with RT, although prospective data are limited in the relapse setting. Surgery for LMDT not only addresses the tumor but also provides tissue for analysis, though the potential surgical morbidity based on location, extent of resection, and recovery complications should be considered. Interventional radiology approaches also can procure tumor tissue while delivering LMDT; there are several different procedures available based on the location, size, and extent of disease. Finally, a combination of LMDT approaches can be used for patients with RR-ES. Decisions regarding the management of RR-ES should involve a multidisciplinary team and factor in the burden of disease, progression-free interval, life expectancy, toxicity profiles of LMDT, and quality of life. In such patients, informed and shared decision making with patients and their families is paramount.

Results of the Latin American Pediatric Oncology Group (GALOP) Trial for Patients With Metastatic Ewing Sarcoma: Multicentric study of Interval-Compressed Multiagent and Metronomic Chemotherapy

BACKGROUND

GALOP investigators developed a multicenter protocol to standardize treatment for newly diagnosed metastatic Ewing sarcoma (ES) in South America.

METHODS

Prospective trial. Induction chemotherapy consisted of 9 alternating interval-compressed cycles (every 14 days) of vincristine, doxorubicin, cyclophosphamide, and ifosfamide-etoposide; local and metastatic site control; and 5 consolidation cycles (every 21 days), followed by MCT with cyclophosphamide and vinblastine for 1 year.

RESULTS

Between 2011 and 2019, 198 patients were recruited from 34 centers in Argentina, Brazil, Chile, and Uruguay. Characteristics include: male patients (60.6%), median age of 12.3 years (range, 0.8-31.1); axial primary localization (62.1%), size >8 cm (70.2%); and bone origin (71.2%). Metastatic sites were lung, extra-lung, and combined in 43.4%, 31.3%, and 25.3%, respectively. The overall response rate was 79.3%, and local treatment was performed in 85.3% of patients. With a median follow-up of 65.1 months (95% CI: 53.9-76.4), the 5-year overall survival (OS) and event-free survival (EFS) were 33.1% (95% CI: 25.9-40.4) and 27.8% (95% CI: 21.5-34.3), respectively. The 5-year OS was 44.9%, 31.3%, and 15.6% for lung, extra-lung, and combined, respectively (p < 0.001). The median interval between induction chemotherapy cycles was 17 days, with a febrile neutropenia rate of 19.3%. Metronomic chemotherapy (MCT) was administered to 100 patients (50.5%), demonstrating good tolerability, with 58 patients completing at least 75% of the scheduled cycles.

CONCLUSION

The implementation of a multicenter protocol incorporating MCT for metastatic ES proved feasible across Latin America.

Comprehensive Analysis of Treatment Approaches in Chest Wall Ewing Sarcoma: The Impact of Tumor Volume on Oncologic Outcomes

Purpose

Local treatment with surgery (S) and radiation therapy (RT) for chest wall Ewing sarcoma (cwES) is often challenging given the extent of the tumor and the aggressiveness of local treatments needed for cure. We report tumor and treatment characteristics, oncologic outcomes, and toxicities of patients with cwES at 2 centers of a single institution.

Methods and Materials

Consecutive patients with cwES treated from 1997 to 2022 were retrospectively reviewed. All patients were treated with standard 5-drug chemotherapy (vincristine, doxorubicin, cyclophosphamide, alternating with ifosfamide and etoposide) before initiation of local therapy. Local treatment was S, RT, or both. The decision on modality and timing was determined by a multidisciplinary sarcoma group or by consensus between sarcoma experts regarding patient preferences.

Results

The cohort consisted of 39 patients. The median age at diagnosis was 19.2 years (range, 3.5-53.6 years). Median tumor volume (TV) was 235.5 mL (range, 5.3-6761.9 mL). The local control (LC) modality was S in 18 patients (46%), RT in 4 (10%), and S + RT in 17 (44%). Four (10%) patients treated with S + RT had R1 margins. The median follow-up was 3.2 years (range, 0.1-21.6 years). Grade 3 radiation-associated toxicity relative to the RT modality was 16.7% and 7.1% for photons (n = 6) and protons (n = 14), respectively. The 2-year LC by modality was 100% for RT (95% CI, 100%-100%), 88.2% (95% CI, 74.2%-100%) for S, and 73.3% (95% CI, 54.0%-99.5%) for S + RT. The 5-year LC, failure-free survival, and overall survival for all patients were 79.7% (95% CI, 67.3%-94.4%), 52.3% (95% CI, 38.1%-71.9%), and 64.2% (95% CI, 49.6%-83.1%), respectively. In univariate and multivariate analysis, TV ≥ 130 mL was associated with a significantly worse 5-year failure-free survival (31.8% TV ≥ 130 mL vs 80.8% TV < 130 mL; hazard ratio, 4.94, p = .013 and adjusted hazard ratio, 5.43; 95% CI, 1.28-22.98; p = .022). The multivariate model was adjusted for age, metastatic disease at diagnosis, and S.

Conclusions

Outcomes for cwES tumors are highly dependent on tumor size, even with the use of combined modality local therapy. With early follow-up, smaller tumors may be well controlled with either S or RT.

Contemporary surgical management of osteosarcoma and Ewing sarcoma

The incidence of malignant bone tumors has remained relatively stable over the past two decades between 8% and 9% per 1,000,000 in North America. Multidisciplinary treatment is paramount for optimal care combining surgical resection, chemotherapy, and rehabilitation. Surgical treatment aims for a negative margin resection of the sarcoma with a personalized reconstruction plan. Limb salvage surgery (LSS) is possible in the majority of cases; however, amputation (including rotationplasty) may be required or preferred. Reconstruction can be achieved utilizing endoprostheses, allograft, autograft, or a combination of these techniques. Emerging technologies such as 3D printing of implants and cutting guides, and intraoperative navigation have helped to improve options for LSS.

Druggable upregulated proteins in EWS-FLI-driven Ewing sarcoma as emerging new therapeutic targets

Ewing sarcoma (ES) is a highly aggressive soft tissue tumor that primarily affects the long bones of children and young adults. It is distinguished by a characteristic chromosomal translocation between the Ewing sarcoma breakpoint region 1 (EWS) gene and the erythroblast transformation-specific (ETS) family of genes, most commonly resulting in the EWS-friend leukemia integration 1 (EWS-FLI1) fusion gene. This translocation is observed in approximately 80%-85% of ES cases. This fusion gene encodes a non-physiological chimeric fusion protein that plays a central role in tumorigenesis by interacting with numerous partner proteins. Several studies have demonstrated the tumorigenic potential of the EWS-FLI1 protein when transfected into non-cancer cell lines. However, targeting EWS-FLI1 directly remains a significant challenge, as no drug to date has been reported to bind to and inhibit its activity effectively. An alternative therapeutic strategy involves targeting key overexpressed protein complexes implicated in ES tumorigenesis, many of which may be downstream interacting partners of EWS-FLI1. This review explores emerging protein targets as potential therapeutic avenues in ES treatment.

Metastatic-Site Radiation Therapy for Ewing Sarcoma and Rhabdomyosarcoma: Consensus Guidelines From the National Pediatric Cancer Foundation

PURPOSE

Despite the urgent need for improved outcomes in patients with metastatic Ewing sarcoma (EWS) and rhabdomyosarcoma (RMS), it is unknown how to best approach metastatic-site radiation therapy for these patients and whether such treatment provides a significant oncologic benefit that outweighs the toxicities.

METHODS AND MATERIALS

We gathered a panel of pediatric radiation oncologists from academic hospitals to identify and discuss current controversies regarding the role of radiation in the management of metastatic EWS and RMS. The panel reviewed existing clinical data and ongoing trials to address 5 key questions: (1) the role of whole lung irradiation (WLI) in treating lung metastases; (2) the number of metastatic sites warranting radiation therapy and the radicality of such an approach; (3) radiation techniques, including stereotactic body radiation therapy (SBRT); (4) the timing of metastatic-site radiation therapy; and (5) the utility of metastatic-site radiation therapy for relapsed metastatic disease.

RESULTS

After a review of existing data, consensus recommendations were developed to support the decision-making process in metastatic-site irradiation, aiming to improve long-term disease control. Patients with pulmonary metastases should receive WLI. In patients with limited (<8 sites) metastatic disease, a comprehensive approach should be taken to treat all sites of metastatic disease diagnosed at presentation. SBRT should be considered as a preferred treatment technique. The timing of metastatic-site treatment should coincide with the end of systemic therapy. However, if there is a dosimetric advantage or improved compliance, concurrent treatment with the primary site may be preferred.

CONCLUSIONS

A consensus guideline was established to address several critical questions regarding the role of radiation in the treatment of metastatic EWS and RMS. The study highlights the existing controversies, provides a structured approach, and underscores the need for future studies to further evaluate the therapeutic ratio of metastatic-site directed therapy.

Signaling pathways and targeted therapies in Ewing sarcoma

Ewing sarcoma, the second most prevalent malignant bone tumor with potential occurrence in soft tissues, exhibits a high level of aggressiveness, primarily afflicting children and adolescents. It is characterized by fusion proteins arising from chromosomal translocations. The fusion proteins induce aberrations in multiple signaling pathways and molecules, constituting a key event in oncogenic transformation. While diagnostic and therapeutic modalities have advanced in recent decades and multimodal treatments, including surgery, radiotherapy, and chemotherapy, have significantly improved survival of patients with localized tumors, patients with metastatic tumors continue to face poor prognoses. There persists a pressing need for novel alternative treatments, yet the translation of our understanding of Ewing sarcoma pathogenesis into improved clinical outcomes remains a critical challenge. Here, we provide a comprehensive review of Ewing sarcoma, including fusion proteins, various signaling pathways, pivotal pathogenetic molecules implicated in its development, and associated targeted therapies and immunotherapies. We summarize past endeavors, current advancements, and deliberate on limitations and future research directions. It is envisaged that this review will furnish novel insights into prospective treatment avenues for Ewing sarcoma.

Primary Mediastinal Ewing's Sarcoma: Post Hoc Analysis from Two International Multicenter Prospective Randomized Trials

OBJECTIVE

Ewing sarcoma (EWS) of the mediastinum is extremely rare, with only a few cases reported in the literature. We aimed to gain a better understanding of primary mediastinal EWS, describing patients treated within two international, multicenter, prospective, randomized EWS trials.

METHODS

Data from patients with primary mediastinal EWS were retrieved from the database of the EURO-E.W.I.N.G.99 (ClinicalTrials.gov identifier: NCT00020566) and EWING 2008 (ClinicalTrials.gov identifier: NCT00987636) trials. Patient and treatment characteristics were analyzed.

RESULTS

Out of 2969 patients with EWS, 9 (0.3%) had primary mediastinal EWS. The median age at diagnosis was 30.5 years (4 to 49). At the time of diagnosis, n = 3 (33%) patients had synchronous metastases. All patients underwent multiagent chemotherapy. Local therapy for non-metastatic patients was surgery (n = 2, 22%), surgery and radiotherapy (n = 2, 22%) or radiotherapy alone (n = 2, 22%). Surgery consisted of extended resections in most patients (n = 3, 33%). Five-year survival for the whole cohort was 64%. Apart from one patient who was lost to follow-up, all patients (n = 4) who had undergone surgery were alive at the end of follow-up.

CONCLUSIONS

Primary mediastinal ES is extremely rare, with a prevalence of 0.3% among EWS. Five-year survival was favorable compared to primary mediastinal sarcoma of all histologies and in line with EWS of different origin.

UK guidelines for the management of bone sarcomas

This document is an update of the British Sarcoma Group guidelines (2016) and provides a reference standard for the clinical care of UK patients with primary malignant bone tumours (PMBT) and giant cell tumours (GCTB) of bone. The guidelines recommend treatments that are effective and should be available in the UK, and support decisions about management and service delivery. The document represents a consensus amongst British Sarcoma Group members in 2024. Key recommendations are that bone pain, or a palpable mass should always lead to further investigation and that patients with clinical or radiological findings suggestive of a primary bone tumour at any anatomic site should be referred to a specialist centre and managed by an accredited bone sarcoma multidisciplinary team. Treatment recommendations are provided for the major tumour types and for localised, metastatic and recurrent disease. Follow-up schedules are suggested.

Radical Resection of a Radial Ewing Sarcoma and Ulnar Centralization in a 10-Month-Old Girl: A Case Report

CASE

We outline the management of a 10-month-old girl with an Ewing sarcoma involving the entire radius. The patient was treated with neoadjuvant chemotherapy resulting in almost a complete response. A limb-sparing procedure was performed consisting of a radical resection of the entire radius and centralization of the carpus to the ulna.

CONCLUSION

This case is the first to describe an Ewing sarcoma of the entire radius in a 10-month-old girl treated with a radical resection of the radius and centralization of the carpus on the ulna. Over 2 years postoperatively, the construct remains stable with a very good functional and aesthetic outcome.

Stakeholder Perspectives on Randomized Clinical Trials for Children With Poor-Prognosis Cancers

Importance

In poor-prognosis children's cancers, new therapies may carry fresh hope for patients and parents. However, there is an absolute requirement for any new therapy to be properly evaluated to fulfill scientific, regulatory, and reimbursement requirements. Randomized clinical trials (RCTs) are considered the gold standard, but no consensus exists on how and when they should be deployed to best meet the needs of all stakeholders.

Objective

To conduct a multistakeholder meeting to foster a greater shared understanding of perspectives regarding RCTs of new therapies for children with poor-prognosis cancers and develop consensus recommendations on when and how they should be used.

Evidence Review

During October 2022 and April 2023, 2 structured workshops were convened, bringing together individuals representing the perspectives of patient advocates and academic clinician-researchers, regulators, and health technology assessment bodies. A premeeting briefing document was prepared and circulated to all attendees. During the workshops, selected attendees presented on behalf of each stakeholder group, focused topic discussions were conducted, and each meeting concluded by agreeing on a consensus set of recommendations. Meeting organizers drafted meeting summary reports that were circulated to all attendees, who commented on and revised them as a group to produce final recommendations from the workshops.

Findings

Though the workshops did not reconcile all stakeholder differences, sufficient areas of agreement enabled a set of conclusions to be drawn, resulting in 8 consensus recommendations: (1) drug development strategies for new therapies, including the role of RCTs, should be established at the time of first-in-child studies; (2) engagement with regulators and health technology assessment bodies about RCT design is crucial; (3) involvement of patient advocates is necessary to ensure that an RCT is patient focused; (4) timing of an RCT is critical to preserve clinical equipoise; (5) use of crossover in an RCT can be of benefit, but with important caveats; (6) end point maturity and overall survival in an RCT may be important for regulatory and health technology assessment approvals; (7) in the absence of an RCT, contemporaneous control cohorts are preferred over historical control cohorts; and (8) quality of life should be captured in all prospective RCTs.

Conclusions and Relevance

The agreed-upon workshop conclusions provide a basis for key considerations while undertaking future drug development activities for children with poor-prognosis cancers, ensuring that the needs and perspectives of all stakeholders are factored in from the outset.

Consensus recommendations for systemic therapies in the management of relapsed Ewing sarcoma: A report from the National Ewing Sarcoma Tumor Board

Ewing sarcoma (ES) is a malignant tumor of bone and soft tissue that most often occurs in children, adolescents, and young adults. Debate and controversy remain in the management of relapsed/refractory ES (RR-ES). The authors leveraged the expertise assembled by the National Ewing Sarcoma Tumor Board, a multidisciplinary virtual tumor board that meets monthly to discuss challenging cases of ES. In this review, they focus on select topics that apply to the management of patients with RR-ES. The specific topics covered include the initial approach of such patients and discussion of the goals of care, the role of molecular testing, chemotherapy regimens and novel agents to consider, the role of maintenance therapy, and the use of high-dose chemotherapy with autologous stem cell rescue. The data referenced are often limited to subgroup analyses and/or compiled from multiple sources. Although not intended to replace the clinical judgement of treating physicians, these guidelines are intended to support clinicians and provide some clarity and recommendations for the management of patients with RR-ES. PLAIN LANGUAGE SUMMARY: Ewing sarcoma (ES) is a bone and soft tissue cancer that most often occurs in teenagers and young adults. This article uses the experience of the National Ewing Sarcoma Tumor Board, a multi-institution, multidisciplinary virtual tumor board that meets monthly to discuss challenging cases of ES and to address questions related to the treatment of patients with relapsed ES. Although not intended to replace the clinical judgement of treating physicians and limited by available data, these consensus recommendations will support clinicians who treat patients with this challenging malignancy, made even more difficult when it recurs.

Impact of age on safety of Busulfan-Melphalan followed by autologous hematopoietic stem-cell transplantation versus standard chemotherapy in the patients of the EURO-E.W.I.N.G. 99 and Ewing 2008 clinical trials

INTRODUCTION

Ewing sarcoma (ES), is a rare cancer affecting children, adolescents and adults. After VIDE (vincristine-ifosfamide-doxorobucin-etoposide) induction chemotherapy, Busulfan-Melphalan (BuMel) high-dose chemotherapy followed by autologous hematopoietic stem cells transplantation improved outcomes in unfavourable localized ES, but with more toxicities than conventional chemotherapy (VAI: Vincristine-dactinomycin-Ifosfamide). We evaluated whether the risk of acute toxicity associated with BuMel compared to VAI varied according to age in patients recruited in the R2Loc and R2Pulm randomised trials of the Euro-E.W.I.N.G.99 and Ewing-2008 trials.

METHODS

We included patients with a localized high-risk disease, or pulmonary or pleural metastasis. We analysed the risk of severe toxicity according to randomised treatment group (VAI versus BuMel) and age group (<12 years, 12-17 years, 18-24 years, ≥25 years). We evaluated the heterogeneity of treatment effects by age group using interaction terms in logistic multivariable models.

RESULTS

The analysis included 243 patients treated with VAI and 205 with BuMel. Overall, BuMel was associated with a higher risk of severe acute toxicity than VAI particularly haematological, gastrointestinal, liver, sinusoidal occlusive syndrome, and infections. Severe haematological toxicity and lower general condition were significantly more frequent in younger patients, whatever treatment. We did not observe any significant heterogeneity in terms of the excess risk of severe toxicities associated with BuMel compared to VAI according to age group.

CONCLUSION

The excess of acute toxicity associated with BuMel compared to VAI does not vary significantly with age, suggesting the feasibility of BuMel across all age groups.

CD99 contributes to the EWS::FLI1 transcriptome by specifically affecting FOXM1-targets involved in the G2/M cell cycle phase, thus influencing the Ewing sarcoma genetic landscape

Ewing sarcoma (EwS), a highly aggressive malignancy affecting children and young adults, is primarily driven by a distinctive oncogenic fusion, the EWSR1-ETS, whose activity is a key source of epigenetic and clinical heterogeneity. CD99 is constantly present in EwS cells, known to modulate the EwS genetic profile and tumor malignancy. However, the relevance of CD99 alone, or in association with EWSR1-ETS chimeras, is poorly understood. We explored the dynamic relationship between CD99 and EWS::FLI1, the main fusion observed in EwS, by means of model systems with inducible expression of either molecule. The transcriptomic dynamics of cells with or without expression of EWS::FLI1 or CD99 were analyzed and correlated with tumor cell growth. The CD99-associated EwS gene profile was found to have commonalities with the profile induced by EWS::FLI1, but also peculiar differences. Both EWS::FLI1 and CD99 are regulated targets of the DREAM complex, but the CD99 expression specifically impacted genes that are the targets of FOXM1 and are involved in the setting of the G2/M phase of the cell cycle. Most CD99-regulated FOXM1-targeted genes were found to correlate with bad prognosis in two public clinical datasets (R2 platform), further supporting the clinical relevance of CD99-mediated regulation of EwS gene expression.

Pediatric Leukemia Roadmaps Are a Guide for Positive Metastatic Bone Sarcoma Trials

ALL cures require many MRD therapies. This strategy should drive experiments and trials in metastatic bone sarcomas.

Biological Sample Collection to Advance Research and Treatment: A Fight Osteosarcoma Through European Research and Euro Ewing Consortium Statement

Osteosarcoma and Ewing sarcoma are bone tumors mostly diagnosed in children, adolescents, and young adults. Despite multimodal therapy, morbidity is high and survival rates remain low, especially in the metastatic disease setting. Trials investigating targeted therapies and immunotherapies have not been groundbreaking. Better understanding of biological subgroups, the role of the tumor immune microenvironment, factors that promote metastasis, and clinical biomarkers of prognosis and drug response are required to make progress. A prerequisite to achieve desired success is a thorough, systematic, and clinically linked biological analysis of patient samples, but disease rarity and tissue processing challenges such as logistics and infrastructure have contributed to a lack of relevant samples for clinical care and research. There is a need for a Europe-wide framework to be implemented for the adequate and minimal sampling, processing, storage, and analysis of patient samples. Two international panels of scientists, clinicians, and patient and parent advocates have formed the Fight Osteosarcoma Through European Research consortium and the Euro Ewing Consortium. The consortia shared their expertise and institutional practices to formulate new guidelines. We report new reference standards for adequate and minimally required sampling (time points, diagnostic samples, and liquid biopsy tubes), handling, and biobanking to enable advanced biological studies in bone sarcoma. We describe standards for analysis and annotation to drive collaboration and data harmonization with practical, legal, and ethical considerations. This position paper provides comprehensive guidelines that should become the new standards of care that will accelerate scientific progress, promote collaboration, and improve outcomes.

Emerging therapies in Ewing sarcoma

PURPOSE OF REVIEW

There is an unmet need to improve outcomes for patients for Ewing sarcoma, a rare, aggressive sarcoma with a peak incidence in adolescents and young adults (AYA). Current therapy at diagnosis involves multiagent chemotherapy and local therapy, but despite intensification of treatment, those with metastases at diagnosis and recurrent disease have poor outcomes.

RECENT FINDINGS

Improved understanding of Ewing sarcoma biology has identified novel targets with promising activity in Ewing sarcoma patients, including tyrosine kinase inhibitors that are now undergoing evaluation as combination and maintenance therapy. Other emerging therapies include those that target the EWSR1::FLI1 fusion oncoprotein, and act on DNA damage, cell cycle and apoptotic pathways. Immunotherapeutic approaches, particularly CAR-T-cell therapy directed at GD2, also hold promise. Recent collaborative clinical trials that have defined an international standard of care for patients with newly diagnosed Ewing sarcoma and novel platform studies with adaptive designs offer unique opportunities to investigate these therapies inclusive of all ages.

SUMMARY

Close international collaboration between clinicians and biologists will allow us to prioritize promising emerging therapies and develop biomarkers to facilitate their incorporation into standard of care and more rapidly translate into benefit for Ewing sarcoma patients.

Kinase Inhibitors and Kinase-Targeted Cancer Therapies: Recent Advances and Future Perspectives

Over 120 small-molecule kinase inhibitors (SMKIs) have been approved worldwide for treating various diseases, with nearly 70 FDA approvals specifically for cancer treatment, focusing on targets like the epidermal growth factor receptor (EGFR) family. Kinase-targeted strategies encompass monoclonal antibodies and their derivatives, such as nanobodies and peptides, along with innovative approaches like the use of kinase degraders and protein kinase interaction inhibitors, which have recently demonstrated clinical progress and potential in overcoming resistance. Nevertheless, kinase-targeted strategies encounter significant hurdles, including drug resistance, which greatly impacts the clinical benefits for cancer patients, as well as concerning toxicity when combined with immunotherapy, which restricts the full utilization of current treatment modalities. Despite these challenges, the development of kinase inhibitors remains highly promising. The extensively studied tyrosine kinase family has 70% of its targets in various stages of development, while 30% of the kinase family remains inadequately explored. Computational technologies play a vital role in accelerating the development of novel kinase inhibitors and repurposing existing drugs. Recent FDA-approved SMKIs underscore the importance of blood-brain barrier permeability for long-term patient benefits. This review provides a comprehensive summary of recent FDA-approved SMKIs based on their mechanisms of action and targets. We summarize the latest developments in potential new targets and explore emerging kinase inhibition strategies from a clinical perspective. Lastly, we outline current obstacles and future prospects in kinase inhibition.

Structural Models for a Series of Allosteric Inhibitors of IGF1R Kinase

The allosteric inhibition of insulin-like growth factor receptor 1 kinase (IGF1RK) is a potential strategy to overcome selectivity barriers for targeting receptor tyrosine kinases. We constructed structural models of a series of 12 indole-butyl-amine derivatives that have been reported as allosteric inhibitors of IGF1RK. We further studied the dynamics and interactions of each inhibitor in the allosteric pocket via all-atom explicit-solvent molecular dynamics (MD) simulations. We discovered that a bulky carbonyl substitution at the R1 indole ring is structurally unfavorable for inhibitor binding in the IGF1RK allosteric pocket. Moreover, we found that the most potent derivative (termed C11) acquires a distinct conformation: forming an allosteric pocket channel with better shape complementarity and interactions with the receptor. In addition to a hydrogen-bonding interaction with V1063, the cyano derivative C11 forms a stable hydrogen bond with M1156, which is responsible for its unique binding conformation in the allosteric pocket. Our findings show that the positioning of chemical substituents with different pharmacophore features at the R1 indole ring influences molecular interactions and binding conformations of indole-butyl-amine derivatives and, hence, dramatically affects their potencies. Our results provide a structural framework for the design of allosteric inhibitors with improved affinities and specificities against IGF1RK.

Structural Models for a Series of Allosteric Inhibitors of IGF1R Kinase

The allosteric inhibition of Insulin-like Growth Factor Receptor 1 Kinase (IGF1RK) is a potential strategy to overcome selectivity barriers in targeting receptor tyrosine kinases. We constructed structural models of a series of 12 indole-butyl-amine derivatives which have been reported as allosteric inhibitors of IGF1RK. We further studied dynamics and interactions of each inhibitor in the allosteric pocket via all-atom explicit-solvent molecular dynamics (MD) simulations. We discovered that a bulky carbonyl substitution at the R1 indole ring is structurally unfavorable for inhibitor binding in the IGF1RK allosteric pocket. Moreover, we found that the most potent derivative (termed C11) acquires a distinct conformation, forming an allosteric pocket channel with better shape complementarity and interactions with the receptor. In addition to a hydrogen bonding interaction with V1063, the cyano derivative C11 forms a stable hydrogen bond with M1156, which is responsible for its unique binding conformation in the allosteric pocket. Our findings show that the position of chemical substituents at the R1 indole ring with different pharmacophore features influences molecular interactions and binding conformations of the indole-butyl-amine derivatives, hence dramatically affecting their potencies. Our results provide a structural framework for the design of allosteric inhibitors with improved affinities and specificities against IGF1RK.

Impact of Consolidative Radiation on Overall and Progression-Free Survival in Pediatric, Adolescent, and Young Adult Metastatic Bone and Soft Tissue Sarcoma

PURPOSE

To determine the association between consolidative radiation (RT) and survival in children, adolescents, and young adults with metastatic sarcoma.

METHODS AND MATERIALS

Eligibility criteria included patients aged ≤39 years with newly diagnosed metastatic bone or soft tissue sarcoma who completed local control of the primary tumor without disease progression. Consolidative RT was defined as RT to all known sites of metastatic disease. The Kaplan-Meier method was used to estimate overall survival (OS) and progression-free survival (PFS). The least absolute shrinkage and selection operator Cox provided adjusted estimates. To account for immortal time bias, consolidative RT was used as a time-varying covariate in a time dependent Cox model. Distant failure was estimated using the Fine-Gray model.

RESULTS

Patients (n = 85) had a median age at diagnosis of 14.8 years. Most common histology was Ewing Sarcoma (45.9%) followed by rhabdomyosarcoma (40.0%). Receipt of consolidative RT was associated with Ewing Sarcoma (P < .001) and local control modality as those who underwent local control with surgery and RT compared with surgery alone were more likely to be treated with consolidative RT (P = .034). Consolidative RT was independently associated with improved OS (hazard ratio [HR], 0.41; 95% CI, 0.17-0.98; P = .045) and improved PFS (HR, 0.37; 95% CI, 0.16-0.88; P = .024) after adjusting for confounding variables and immortal time bias. Patients treated with consolidative RT also experienced a lower risk of distant failure (HR, 0.33; 95% CI, 0.17-0.64; P = .001). In an independent data set of patients with metachronous progression (n = 36), consolidative RT remained independently associated with improved OS.

CONCLUSIONS

Consolidative RT was independently associated with improved OS and PFS and decreased risk of distant failure in child, adolescent, and young adult patients with metastatic sarcoma. Future work should evaluate biomarkers to optimize patient selection, timing, and dose for consolidative RT.

Recent advances in the treatment of childhood cancers

PURPOSE OF REVIEW

Although cancer remains the leading nonaccidental cause of mortality in children, substantial advances in care have led to 5-year overall survival exceeding 85%. However, improvements in outcomes have not been uniform across malignancies or strata of social determinants of health. The current review highlights recent areas of advancement and anticipated directions for future progress.

RECENT FINDINGS

Incorporation of rational targeted agents into upfront treatment regimens has led to incremental improvements in event-free survival for many children, sometimes with potential reductions in late effects. For rare or challenging-to-treat cancers, the increasing feasibility of molecular profiling has provided specific treatment options to patients with some of the greatest needs. Simultaneously, increased focus is being given to patient-reported outcomes and social determinants of health, the importance ofwhich are becoming readily recognized in providing equitable, quality care. Finally, as survival from malignant diseases improves, breakthroughs in the prevention and management of adverse late effects will promote long-term quality of life.

SUMMARY

Multi-institutional collaboration and risk-adapted approaches have been crucial to recent advancements in the care of children with cancer and inform potential directions for future investigation.

Regorafenib in patients with advanced Ewing sarcoma: results of a non-comparative, randomised, double-blind, placebo-controlled, multicentre Phase II study

BACKGROUND

The REGOBONE multi-cohort study explored the efficacy and safety of regorafenib for patients with advanced bone sarcomas; this report details the Ewing sarcoma (ES) cohort.

METHODS

Patients with relapsed ES progressing despite prior standard therapy, were randomised (2:1) to receive regorafenib or placebo. Patients on placebo could crossover to receive regorafenib after centrally confirmed progression. The primary endpoint was the progression-free rate at 8 weeks. With one-sided α of 0.05, and 80% power, at least 14/24 progression-free patients at 8 weeks were needed for success.

RESULTS

From September 2014 to November 2019, 41 patients were accrued. 36 patients were evaluable for efficacy: 23 on regorafenib and 13 on placebo. Thirteen patients (56%; one-sided 95% CI [37.5%-[)) were progression-free at 8 weeks on regorafenib vs. 1 (7.7%; 95% CI [0.4%-[) on placebo. Median PFS was 11.4 weeks on regorafenib, and 3.9 weeks on placebo. Ten placebo patients crossed over to receive regorafenib after progression. The most common grade ≥3 regorafenib-related adverse events were pain (22%), asthenia (17%), thrombocytopenia (13%) and diarrhoea (13%).

CONCLUSION

Although the primary endpoint was not met statistically in this randomised cohort, there is evidence to suggest that regorafenib might modestly delay tumour progression in relapsed ES after failure of prior chemotherapy.

Consensus recommendations in the management of Ewing sarcoma from the National Ewing Sarcoma Tumor Board

Ewing sarcoma (ES) is a malignant tumor of bone and soft tissue that most often occurs in adolescents and young adults. Despite an international coordinated approach, several nuances, discrepancies, and debates remain in defining the standard of care for treating ES. In this review, the authors leverage the expertise assembled by formation of the National Ewing Sarcoma Tumor Board, a multi-institution, multidisciplinary virtual tumor board that meets monthly to discuss complicated and challenging cases of ES. This report is focused on select topics that apply to the management of patients with newly diagnosed ES. The specific topics covered include indications for bone marrow aspirate and biopsy for initial evaluation compared with fluorodeoxyglucose-positron emission tomography, the role of interval compressed chemotherapy in patients aged 18 years and older, the role of adding ifosfamide/etoposide to vincristine/doxorubicin/cyclophosphamide for patients with metastatic disease, the data on and role of high-dose chemotherapy with autologous stem cell transplantation, maintenance therapy, and whole-lung irradiation. The data referenced are often limited to subgroup analyses and/or compiled from multiple sources. Although not intended to replace the clinical judgement of treating physicians, the guidelines are intended to provide clarity and recommendations for the upfront management of patients with ES. PLAIN LANGUAGE SUMMARY: Ewing sarcoma is a malignant tumor of bone and soft tissue that most often occurs in adolescents and young adults. For this review, the authors used the experience of the National Ewing Sarcoma Tumor Board, a multi-institution, multidisciplinary virtual tumor board that meets monthly to discuss complicated and challenging cases of Ewing sarcoma. Although not intended to replace the clinical judgement of treating physicians, the guidelines will focus on the development of consensus statements for the upfront management of patients with Ewing sarcoma.

IGF-1R targeting in cancer - does sub-cellular localization matter?

The insulin-like growth factor receptor (IGF-1R) was among the most intensively pursued kinase targets in oncology. However, even after a slew of small-molecule and antibody therapeutics reached clinical trials for a range of solid tumors, the initial promise remains unfulfilled. Mechanisms of resistance to, and toxicities resulting from, IGF-1R-targeted drugs are well-catalogued, and there is general appreciation of the fact that a lack of biomarker-based patient stratification was a limitation of previous clinical trials. But no next-generation therapeutic strategies have yet successfully exploited this understanding in the clinic.Currently there is emerging interest in re-visiting IGF-1R targeted therapeutics in combination-treatment protocols with predictive biomarker-driven patient-stratification. One such biomarker that emerged from early clinical trials is the sub-cellular localization of IGF-1R. After providing some background on IGF-1R, its drugging history, and the trials that led to the termination of drug development for this target, we look more deeply into the correlation between sub-cellular localization of IGF-1R and susceptibility to various classes of IGF-1R - targeted agents.

Artificial intelligence-based radiomics in bone tumors: Technical advances and clinical application

Radiomics is the extraction of predefined mathematic features from medical images for predicting variables of clinical interest. Recent research has demonstrated that radiomics can be processed by artificial intelligence algorithms to reveal complex patterns and trends for diagnosis, and prediction of prognosis and response to treatment modalities in various types of cancer. Artificial intelligence tools can utilize radiological images to solve next-generation issues in clinical decision making. Bone tumors can be classified as primary and secondary (metastatic) tumors. Osteosarcoma, Ewing sarcoma, and chondrosarcoma are the dominating primary tumors of bone. The development of bone tumor model systems and relevant research, and the assessment of novel treatment methods are ongoing to improve clinical outcomes, notably for patients with metastases. Artificial intelligence and radiomics have been utilized in almost full spectrum of clinical care of bone tumors. Radiomics models have achieved excellent performance in the diagnosis and grading of bone tumors. Furthermore, the models enable to predict overall survival, metastases, and recurrence. Radiomics features have exhibited promise in assisting therapeutic planning and evaluation, especially neoadjuvant chemotherapy. This review provides an overview of the evolution and opportunities for artificial intelligence in imaging, with a focus on hand-crafted features and deep learning-based radiomics approaches. We summarize the current application of artificial intelligence-based radiomics both in primary and metastatic bone tumors, and discuss the limitations and future opportunities of artificial intelligence-based radiomics in this field. In the era of personalized medicine, our in-depth understanding of emerging artificial intelligence-based radiomics approaches will bring innovative solutions to bone tumors and achieve clinical application.

Children's Oncology Group's 2023 blueprint for research: Bone tumors

The Children's Oncology Group (COG) Bone Tumor Committee is responsible for clinical trials and biological research on localized, metastatic, and recurrent osteosarcoma and Ewing sarcoma (EWS). Results of clinical trials in localized disease completed and published in the past 10 years have led to international standard-of-care chemotherapy for osteosarcoma and EWS. A recent focus on identifying disease subgroups has led to the identification of biological features associated with poor outcomes including the presence of circulating tumor DNA (ctDNA) at diagnosis, and specific genomic alterations-MYC amplification for osteosarcoma and STAG2 and TP53 mutation for EWS. Studies validating these potential biomarkers are under way. Clinical trials evaluating the addition of multitargeted kinase inhibitors, which are active in relapsed bone sarcomas, to standard chemotherapy are under way in osteosarcoma and planned in EWS. In addition, the Committee has data analyses and a clinical trial under way to evaluate approaches to local management of the primary tumor and metastatic sites. Given the rarity of bone sarcomas, we have prioritized international interactions and are in the process of forming an international data-sharing consortium to facilitate refinement of risk stratification and study of rare disease subtypes.

Children's Oncology Group's 2023 blueprint for research: Radiation oncology

Radiation oncology is an integral part of the multidisciplinary team caring for children with cancer. The primary goal of our committee is to enable the delivery of the safest dose of radiation therapy (RT) with the maximal potential for cure, and to minimize toxicity in children by delivering lower doses to normal tissues using advanced technologies like intensity-modulated RT (IMRT) and proton therapy. We provide mentorship for y ators and are actively involved in educating the global radiation oncology community. We are leaders in the effort to discover novel radiosensitizers, radioprotectors, and advanced RT technologies that could help improve outcomes of children with cancer.

Phase 2 trial of palbociclib and ganitumab in patients with relapsed Ewing sarcoma

BACKGROUND

Ewing sarcoma (EWS) is an aggressive sarcoma with few treatment options for patients with relapsed disease. Cyclin-dependent kinase 4 (CDK4) is a genomic vulnerability in EWS that is synergistic with IGF-1R inhibition in preclinical studies. We present the results of a phase 2 study combining palbociclib (CDK4/6 inhibitor) with ganitumab (IGF-1R monoclonal antibody) for patients with relapsed EWS.

PATIENTS AND METHODS

This open-label, non-randomized, phase 2 trial enrolled patients ≥12 years with relapsed EWS. All patients had molecular confirmation of EWS and RECIST measurable disease. Patients initially received palbociclib 125 mg orally on Days 1-21 and ganitumab 18 mg/kg intravenously on Days 1 and 15 of a 28-day cycle. The primary endpoints were objective response (complete or partial) per RECIST and toxicity by CTCAE. An exact one-stage design required ≥4 responders out of 15 to evaluate an alternative hypothesis of 40% response rate against a null of 10%. The study was closed following enrollment of the 10th patient due to discontinuation of ganitumab supply.

RESULTS

Ten evaluable patients enrolled [median age 25.7 years (range 12.3-40.1)]. The median duration of therapy was 2.5 months (range 0.9-10.8). There were no complete or partial responders. Three of 10 patients had stable disease for >4 cycles and 2 had stable disease at completion of planned therapy or study closure. Six-month progression-free survival was 30% (95% CI 1.6%-58.4%). Two patients had cycle 1 hematologic dose-limiting toxicities (DLTs) triggering palbociclib dose reduction to 100 mg daily for 21 days. Two subsequent patients had cycle 1 hematologic DLTs at the reduced dose. Eighty percent of patients had grade 3/4 AEs, including neutropenia (n = 8), white blood cell decreased (n = 7), and thrombocytopenia (n = 5). Serum total IGF-1 significantly increased (p = 0.013) and ctDNA decreased during the first cycle.

CONCLUSIONS

This combination lacks adequate therapeutic activity for further study, though a subset of patients had prolonged stable disease.

Targeting receptor tyrosine kinase signaling: Avenues in the management of cutaneous squamous cell carcinoma

Non-melanoma skin cancer (NMSC) is the most frequently diagnosed cancer worldwide. Among the various types of NMSCs, cutaneous squamous cell carcinoma (cSCC) exhibits more aggressive phenotype and is also the second-most prevalent type. Receptor tyrosine kinases (RTK) triggers key signaling events that play critical roles in the development of various cancers including cSCC. Unsurprisingly, for this reason, this family of proteins has become the cynosure of anti-cancer drug discovery pipelines and is also being considered as attractive targets against cSCC. Though inhibition of RTKs in cSCC has yielded favourable results, there is still scope for bettering the therapeutic outcome. In this review, we discuss the relevance of RTK signaling in the progression of cutaneous squamous cell carcinoma, and observations from clinical trials that used RTK inhibitors against cSCC. Backed by results from preclinical studies, including those from our lab, we also give insights into the scope of using some natural products as effective suppressors of RTK signaling and skin carcinogenesis.

Emerging Intrinsic Therapeutic Targets for Metastatic Breast Cancer

Breast cancer is now the most common cancer worldwide, and it is also the main cause of cancer-related death in women. Survival rates for female breast cancer have significantly improved due to early diagnosis and better treatment. Nevertheless, for patients with advanced or metastatic breast cancer, the survival rate is still low, reflecting a need for the development of new therapies. Mechanistic insights into metastatic breast cancer have provided excellent opportunities for developing novel therapeutic strategies. Although high-throughput approaches have identified several therapeutic targets in metastatic disease, some subtypes such as triple-negative breast cancer do not yet have an apparent tumor-specific receptor or pathway to target. Therefore, exploring new druggable targets in metastatic disease is a high clinical priority. In this review, we summarize the emerging intrinsic therapeutic targets for metastatic breast cancer, including cyclin D-dependent kinases CDK4 and CDK6, the PI3K/AKT/mTOR pathway, the insulin/IGF1R pathway, the EGFR/HER family, the JAK/STAT pathway, poly(ADP-ribose) polymerases (PARP), TROP-2, Src kinases, histone modification enzymes, activated growth factor receptors, androgen receptors, breast cancer stem cells, matrix metalloproteinases, and immune checkpoint proteins. We also review the latest development in breast cancer immunotherapy. Drugs that target these molecules/pathways are either already FDA-approved or currently being tested in clinical trials.

Shifting from a Biological-Agnostic Approach to a Molecular-Driven Strategy in Rare Cancers: Ewing Sarcoma Archetype

Sarcomas of the thoracic cavity are rare entities that predominantly affect children and young adults. They can be very heterogeneous encompassing several different histological entities. Ewing Sarcoma (ES) can potentially arise from every bone, soft tissue, or visceral site in the body. However, it represents an extremely rare finding when it affects the thoracic cavity. It represents the second most frequent type of thoracic sarcoma, after chondrosarcoma. ES arises more frequently in sites that differ from the thoracic cavity, but it displays the same biological features and behavior of extra-thoracic ones. Current management of ES often requires a multidisciplinary treatment approach including surgery, radiotherapy, and systemic therapy, as it can guarantee local and distant disease control, at least transiently, although the long-term outcome remains poor. Unfortunately, due to the paucity of clinical trials purposely designed for this rare malignancy, there are no optimal strategies that can be used for disease recurrence. As a result of its complex biological features, ES might be suitable for emerging biology-based therapeutic strategies. However, a deeper understanding of the molecular mechanisms driving tumor growth and treatment resistance, including those related to oncogenic pathways, epigenetic landscape, and immune microenvironment, is necessary in order to develop new valid therapeutic opportunities. Here, we provide an overview of the most recent therapeutic advances for ES in both the preclinical and clinical settings. We performed a review of the current available literature and of the ongoing clinical trials focusing on new treatment strategies, after failure of conventional multimodal treatments.