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PURPOSE Monoclonal antibodies directed against insulin-like growth factor-1 receptor (IGF-1R) have shown activity in patients with relapsed Ewing sarcoma. The primary objective of Children's Oncology Group trial AEWS1221 was to determine if the addition of the IGF-1R monoclonal antibody ganitumab to interval-compressed chemotherapy improves event-free survival (EFS) in patients with newly diagnosed metastatic Ewing sarcoma. METHODS Patients were randomly assigned 1:1 at enrollment to standard arm (interval-compressed vincristine/doxorubicin/cyclophosphamide alternating once every 2 weeks with ifosfamide/etoposide = VDC/IE) or to experimental arm (VDC/IE with ganitumab at cycle starts and as monotherapy once every 3 weeks for 6 months after conventional therapy). A planned sample size of 300 patients was projected to provide 81% power to detect an EFS hazard ratio of 0.67 or smaller for the experimental arm compared with the standard arm with a one-sided α of .025. RESULTS Two hundred ninety-eight eligible patients enrolled (148 in standard arm; 150 in experimental arm). The 3-year EFS estimates were 37.4% (95% CI, 29.3 to 45.5) for the standard arm and 39.1% (95% CI, 31.3 to 46.7) for the experimental arm (stratified EFS-event hazard ratio for experimental arm 1.00; 95% CI, 0.76 to 1.33; 1-sided, P = .50). The 3-year overall survival estimates were 59.5% (95% CI, 50.8 to 67.3) for the standard arm and 56.7% (95% CI, 48.3 to 64.2) for the experimental arm. More cases of pneumonitis after radiation involving thoracic fields and nominally higher rates of febrile neutropenia and ALT elevation were reported on the experimental arm. CONCLUSION Ganitumab added to interval-compressed chemotherapy did not significantly reduce the risk of EFS event in patients with newly diagnosed metastatic Ewing sarcoma, with outcomes similar to prior trials without IGF-1R inhibition or interval compression. The addition of ganitumab may be associated with increased toxicity.

Bone sarcomas are rare heterogeneous tumors that affect patients of all ages including children, adolescent young adults, and older adults. They include many aggressive subtypes and patient groups with poor outcomes, poor access to clinical trials, and lack of defined standard therapeutic strategies. Conventional chondrosarcoma remains a surgical disease, with no defined role for cytotoxic therapy and no approved targeted systemic therapies. Here, we discuss promising novel targets and strategies undergoing evaluation in clinical trials. Multiagent chemotherapy has greatly improved outcomes for patients with Ewing sarcoma (ES) and osteosarcoma, but management of those with high-risk or recurrent disease remains challenging and controversial. We describe the impact of international collaborative trials, such as the rEECur study, that aim to define optimal treatment strategies for those with recurrent, refractory ES, and evidence for high-dose chemotherapy with stem-cell support. We also discuss current and emerging strategies for other small round cell sarcomas, such as CIC-rearranged, BCOR-rearranged tumors, and the evaluation of emerging novel therapeutics and trial designs that may offer a new paradigm to improve survival in these aggressive tumors with notoriously bad (to the bone) outcomes.

Comparison of tumor PD-L1 expression and tumor immune infiltrate between baseline biopsies and at 8 weeks on treatment (UPS/DDLPS only)

Purpose:We recently reported a 17.5% objective RECIST 1.1 response rate in a phase II study of pembrolizumab in patients with advanced sarcoma (SARC028). The majority of responses occurred in undifferentiated pleomorphic sarcoma (UPS) and dedifferentiated liposarcoma (DDLPS). We sought to determine whether we can identify immune features that correlate with clinical outcomes from tumor tissues obtained pre- and on-treatment.Patients and Methods:Pretreatment (n = 78) and 8-week on-treatment (n = 68) tumor biopsies were stained for PD-L1 and multiplex immunofluorescence panels. The density of positive cells was quantified to determine associations with anti–PD-1 response.Results:Patients that responded to pembrolizumab were more likely to have higher densities of activated T cells (CD8+ CD3+ PD-1+) and increased percentage of tumor-associated macrophages (TAM) expressing PD-L1 pre-treatment compared with non-responders. Pre-treatment tumors from responders also exhibited higher densities of effector memory cytotoxic T cells and regulatory T cells compared with non-responders. In addition, higher density of cytotoxic tumor-infiltrating T cells at baseline correlated with a better progression-free survival (PFS).Conclusions:We show that quantitative assessments of CD8+ CD3+ PD-1+ T cells, percentage of TAMs expressing PD-L1, and other T-cell densities correlate with sarcoma response to pembrolizumab and improved PFS. Our findings support that multiple cell types present at the start of treatment may enhance tumor regression following anti–PD-1 therapy in specific advanced sarcomas. Efforts to confirm the activity of pembrolizumab in an expansion cohort of patients with UPS/DDLPS are underway.

Comparison of tumor PD-L1 expression and tumor immune infiltrate between baseline tumor biopsies from responders and nonresponders (STS only)

Comparison of tumor PD-L1 expression and tumor immune infiltrate between baseline biopsies and at 8 weeks on treatment (STS only)

Response to anti-PD1 therapy is associated with higher levels of PD-L1 expression by (A) tumor cells and (B) tumor infiltrating macrophages and higher density of sarcoma-associated immune infiltrates at baseline. Tumor biopsies obtained from patients who responded to pembrolizumab therapy had higher baseline density (cell count/mm2) of tumor infiltrating (C) T lymphocytes, (D) cytotoxic T lymphocytes, (E) antigen experience T lymphocytes, (F) antigen experienced cytotoxic T lymphocytes, (G) activated cytotoxic T lymphocytes, (H) effector memory cytotoxic T lymphocytes, and (I) regulatory T lymphocytes. Baseline tumor samples available for immune profiling by IHC were obtained prior to anti-PD1 treatment (8 responder and 58 non-responder patients). Error bars represent SEM. * = p{less than or equal to}0.05, ** = p{less than or equal to}0.01, *** = p{less than or equal to}0.001, n.s. = not significant.

Comparison of tumor PD-L1 expression and tumor immune infiltrate between baseline biopsies and at 8 weeks on treatment (bone only)

SARC028 tumor biopsies obtained at baseline and after 8 weeks treatment and associated patient response to pembrolizumab

Supplemental Legend

Demographic and clinical characteristics of 84 eligible, treated patients

Comparison of tumor PD-L1 expression and tumor immune infiltrate between baseline tumor biopsies from responders and nonresponders (UPS/DDLPS only)

Background Immune checkpoint inhibitors (ICIs) have shown modest antitumor activity in unselected advanced sarcomas. Histology driven approach to patient selection is the current standard for off-label anti-programmed cell death 1 (PD1) immunotherapy use. Methods We retrospectively reviewed the clinical characteristics and outcomes of patients with advanced sarcoma who were treated with off label anti-PD1 immunotherapy at our center. Results A total of 84 patients with 25 histological subtypes were included. Nineteen patients (23%) had a cutaneous primary tumor site. Eighteen patients (21%) were classified as having clinical benefit, including 1 patient with complete response, 14 with partial response, and 3 with stable disease lasting over 6 months with previously progressive disease. Cutaneous primary site location was associated with higher clinical benefit rate (58% vs. 11%, p . 2.5 months, p = 0.003) and OS (19.0 vs. 9.2 months, p = 0.011), compared to non-cutaneous primary. Patients with histological subtypes that pembrolizumab is indicated per current National Comprehensive Cancer Network guidelines had modestly higher rate of clinical benefit versus other histologies, however, the difference was statistically insignificant (29% vs. 15%, p = 0.182) and no statistically significant difference in PFS or OS was observed between these groups. Immune-related adverse events were more frequently seen among patients with clinical benefit (72% vs. 35%, p = 0.007). Conclusions Anti-PD1-based immunotherapy is highly efficacious in advanced sarcomas of cutaneous primary site. Cutaneous primary site location is a stronger predictor of ICI response than histologic subtype and should be accounted for in treatment guidelines and clinical trial design.

The current paradigm of clinical trials treating patients until disease progression using maximum tolerated dose does not account for the dynamic tumor-host-drug interactions that result in acquired resistance. Here, we present the concept of an Evolutionary Tumor Board (ETB) and report interim results from a prospective, non-interventional pilot study in which novel therapeutic strategies based on evolutionary principles were developed under the ETB framework. The ETB approach relies on an interdisciplinary team that integrates clinical, preclinical, and theoretical knowledge and the application of mathematical modeling to predict patient responses to different therapies, including novel approaches derived from eco-evolutionary first principles. We have previously proposed several evolutionary therapies that aim to enhance the efficacy of an overall treatment regimen, using existing agents for a given disease. Key among these evolutionary therapies is the idea of “first-strike second-strike”, where different agents are administered in sequence, and new strikes are applied as soon as the efficacy of the previous strike is nearing a minimum, as opposed to waiting until progression is identified on periodic imaging. This approach requires careful analysis of longitudinal patient data coupled with predictive dynamics generated by mathematical models. Here we describe the ETB process and the interim results from 15 patients enrolled in the feasibility trial. In addition, we describe the challenges faced as well as the solutions that can be implemented via improved modeling approaches, better patient data collection, and a reassessment of how we understand tumor dynamics in the light of evolutionary principles.

Sarcomas are relatively rare malignancies accounting for about 1% of all cancer diagnoses. Studies on sarcomas comprising large cohorts covering extended time periods are lacking. Therefore, this study aimed to evaluate the impact of demographic, behavioral, and clinical characteristics on overall survival (OS) among individuals diagnosed with soft tissue sarcoma (STS) or bone sarcoma at the Moffitt Cancer Center between 1986 and 2014. Unadjusted and multivariable Cox proportional hazard regression (CPHR) models were constructed to generate hazard ratios (HRs) and 95% confidence intervals (CIs) to evaluate associations between a range of demographic, behavioral, and clinical characteristics, and OS. Additionally, Kaplan–Meier survival curves, associated log-rank statistics, and adjusted CPHR models were generated by time periods based on the year of first contact (1986–1994, 1995–1999, 2000–2005, 2006–2010, 2011–2014) to evaluate for temporal differences in OS. Of the 2570 patients, 2037 were diagnosed with STS, whereas 533 were diagnosed with bone sarcoma. At the time of analysis, 50% of the population were alive. In multivariable analyses, we observed poorer survival for patients ≥ 40 years of age (HR = 1.54, 95% CI = 1.34–1.78), current smokers (HR = 1.18, 95% CI = 1.01–1.37), patients with metastasis (HR = 2.19, 95% CI = 1.95–2.47), and patients not receiving first-line surgery treatment (HR = 2.11, 95% CI = 1.82–2.45). We discovered limited improvements in OS over time among individuals diagnosed with STS or bone sarcomas with the exception of gastrointestinal stromal tumors (GIST), which showed a significant improvement in OS across time periods (p = 0.0034). Overall, we identified well-established characteristics associated with OS (e.g., metastasis) in addition to factors (e.g., smoking status) not previously reported to impact OS. Improvements in survival over time have been relatively modest, suggesting the need for improved therapeutic options, especially for those diagnosed with less frequent sarcomas.

The replicative Cdc45-MCM-GINS (CMG) helicase is a large protein complex that functions in the DNA melting and unwinding steps as a component of replisomes during DNA replication in mammalian cells. Although the CMG performs this important role in cell growth, the CMG is not a simple bystander in cell cycle events. Components of the CMG, specifically the MCM precursors, are also involved in maintaining genomic stability by regulating DNA replication fork speeds, facilitating recovery from replicative stresses, and preventing consequential DNA damage. Given these important functions, MCM/CMG complexes are highly regulated by growth factors such as TGF-ß1 and by signaling factors such as Myc, Cyclin E, and the retinoblastoma protein (Rb). Mismanagement of MCM/CMG complexes when these signaling mediators are deregulated, and in the absence of the tumor suppressor protein p53, leads to increased genomic instability and is a contributor to tumorigenic transformation and tumor heterogeneity. The goal of this review is to provide insight into the mechanisms and dynamics by which the CMG is regulated during its assembly and activation in mammalian genomes, and how errors in CMG regulation due to oncogenic changes promote tumorigenesis. Finally, and most importantly, we highlight the emerging understanding of the CMG helicase as an exploitable vulnerability and novel target for therapeutic intervention in cancer.

Background: In ultra-rare sarcomas (URS) the conduction of prospective, randomized trials is challenging. Data from retrospective observational studies (ROS) may represent the best evidence available. ROS implicit limitations led to poor acceptance by the scientific community and regulatory authorities. In this context, an expert panel from the Connective Tissue Oncology Society (CTOS), agreed on the need to establish a set of minimum requirements for conducting high-quality ROS on the activity of systemic therapies in URS. Methods: Representatives from > 25 worldwide sarcoma reference centres met in November 2020 and identified a list of topics summarizing the main issues encountered in ROS on URS. An online survey on these topics was distributed to the panel; results were summarized by descriptive statistics and discussed during a second meeting (November 2021). Results: Topics identified by the panel included the use of ROS results as external control data, the criteria for contributing centers selection, modalities for ensuring a correct pathological diagnosis and radiologic assessment, consistency of surveillance policies across centers, study end-points, risk of data duplication, results publication. Based on the answers to the survey (55 of 62 invited experts) and discussion the panel agreed on 18 statements summarizing principles of recommended practice. Conclusions: These recommendations will be disseminated by CTOS across the sarcoma community and incorporated in future ROS on URS, to maximize their quality and favor their use as control data when results from prospective studies are unavailable. These recommendations could help the optimal conduction of ROS also in other rare tumors.

Osteosarcoma (OS) frequently metastasizes to lung where it greatly contributes to patient mortality. Frustratingly, OS treatment options have remained static due to a paucity of strong pre-clinical evidence to motivate clinical trials. To identify therapeutic targets, we assessed a number of FDA approved therapies for their cytotoxic effects. We found that histone deacetylase (HDAC) inhibitors (panobinostat and romidepsin) limited OS viability at low nM and were highly effective for the treatment of lung metastatic disease in vivo. Although clinically approved, HDAC inhibitors have noted toxicities. Therefore, we next examined the potential mechanisms through which HDAC controlled OS growth. Gene expression analyses on romidepsin treated OS cells revealed key up and downregulated targets. We found that SLC17A7, a vesicular glutamate transporter, was highly and consistently induced in response to romidepsin (greater than 100 fold more than base line) across multiple OS cell lines. Functionally, SLC17A7 traps glutamate in cytoplasmic synaptic vesicles that are then released via exocytosis. Our data show that HDAC inhibition reduces glutamate secretion from OS cells while SLC17A7 overexpression significantly impaired OS viability. Further, we showed that the glutamate export inhibitor, riluzole, significantly impairs the OS growth in vitro and is highly effective for the treatment of lung metastatic OS in vivo. Taken together, we conclude that HDAC1/2 suppression of SLC17A7 ensures high cytoplasmic glutamate levels that can be leveraged for OS growth. We posit that targeting glutamate usage by OS cells using FDA approved inhibitors such as riluzole will be highly effective for the treatment of lung metastatic OS. Citation Format: Niveditha Nerlakanti, Jeremy McGuire, Ryan T. Bishop, Diana Yu, Damon R. Reed, Conor C. Lynch. Delineating the role of vesicular glutamate transporter SLC17A7 in osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 276.

Rationale: Hypoxic regions (habitats) within tumors are heterogeneously distributed and can be widely variant. Hypoxic habitats are generally pan-therapy resistant. For this reason, hypoxia-activated prodrugs (HAPs) have been developed to target these resistant volumes. The HAP evofosfamide (TH-302) has shown promise in preclinical and early clinical trials of sarcoma. However, in a phase III clinical trial of non-resectable soft tissue sarcomas, TH-302 did not improve survival in combination with doxorubicin (Dox), possibly due to a lack of patient stratification based on hypoxic status. Therefore, we used magnetic resonance imaging (MRI) to identify hypoxic habitats and non-invasively follow therapies response in sarcoma mouse models. Methods: We developed deep-learning (DL) models to identify hypoxia, using multiparametric MRI and co-registered histology, and monitored response to TH-302 in a patient-derived xenograft (PDX) of rhabdomyosarcoma and a syngeneic model of fibrosarcoma (radiation-induced fibrosarcoma, RIF-1). Results: A DL convolutional neural network showed strong correlations (>0.76) between the true hypoxia fraction in histology and the predicted hypoxia fraction in multiparametric MRI. TH-302 monotherapy or in combination with Dox delayed tumor growth and increased survival in the hypoxic PDX model (p

Patients with childhood, adolescent, and young adult cancer who will be treated with gonadotoxic therapies are at increased risk for infertility. Many patients and their families desire biological children but effective communication about treatment-related infertility risk and procedures for fertility preservation does not always happen. The PanCareLIFE Consortium and the International Late Effects of Childhood Cancer Guideline Harmonization Group reviewed the literature and developed a clinical practice guideline that provides recommendations for ongoing communication methods for fertility preservation for patients who were diagnosed with childhood, adolescent, and young adult cancer at age 25 years or younger and their families. Moreover, the guideline panel formulated considerations of the ethical implications that are associated with these procedures. Grading of Recommendations Assessment, Development and Evaluation methodology was used to grade the evidence and recommendations. In this clinical practice guideline, existing evidence and international expertise are combined to develop transparent recommendations that are easy to use to facilitate ongoing communication between health-care providers and patients with childhood, adolescent, and young adult cancer who might be at high risk for fertility impairment and their families.

ARST1321, a trial of patients with advanced soft tissue sarcoma, was the first National Clinical Trials Network study codeveloped by pediatric and adult consortia with two treatment cohorts. We report on the findings of a survey to identify barriers to enrolling adolescent and young adult patients (15-39 years) onto the nonchemotherapy arm. The survey response rate was 31% with a 70% completion rate. Common identified reasons for low accrual in order of decreasing frequency included insufficient funding, lack of study awareness or interest, competing trials, toxicity concerns, philosophical differences in the therapy backbone, and regulatory and infrastructure barriers. Clinical Trials.gov ID: NCT02180867.

Background Soft tissue sarcomas (STS) are rare and heterogeneous tumors making chemotherapy use controversial. Our goal was to identify a subset of patients with primary STS that benefit with the addition of chemotherapy. Methods A retrospective chart review included intermediate to high-grade localized primary STS of the extremity/trunk, and tumor size > 5 cm. The effect of chemotherapy was evaluated for local control (LC), distant control (DC), progression free survival (PFS), and overall survival (OS). Results In this cohort (n = 273), patients were treated with surgery (98%), radiation (81%), and chemotherapy (24.5%). With a median follow-up of 51 months, the entire cohort’s 5-year LC, DC, PFS, and OS are 79.1%, 59.9%, 43.8%, and 68.7%, respectively. The addition of chemotherapy did not provide a DC benefit (p = 0.238) for the entire cohort. High-grade disease (n = 210) experienced a 5-year benefit in DC (68% vs. 54.4%, p = 0.04), which was more pronounced with MAI (Mesna, Adriamycin, Ifosfamide) based regimens (74.2%, p = 0.016), and a 5-year PFS (50.8% vs 45%, p = 0.025) and OS benefit (76.2% vs 70%, p = 0.067) vs. no chemotherapy. On multivariate analysis of the high-grade subset, chemotherapy independently predicted for a DC benefit (HR 0.48 95% CI 0.26–89, p = 0.019). The benefit of chemotherapy was more pronounced with MAI, showing a significant benefit in DC (HR 0.333 95% CI 0.145–0.767, p = 0.01) and PFS (HR 0.52 95% CI 0.28–0.99, p = 0.047). Conclusion In patients with localized STS > 5 cm, the high-grade subset had a distant control benefit with the addition of chemotherapy, leading to improved progression free survival. This is more pronounced with the use of MAI and should be considered in patients eligible for this regimen.

Lessons from extinction can be used in trials designed to pursue a cure for cancer. When cancer cannot be cured, similar strategies may be unwise, and strategies that leverage the adaptations of cancer to therapy should be considered.

OBJECTIVE: Adolescent and young adult (AYA) cancer patients have distinct medical and psychosocial needs and fertility is a key concern. Early age of onset is a risk factor for hereditary cancer and AYAs are more likely to experience reduced fertility. This has implications for future family building decisions and fertility preservation (FP) and genetic testing/counseling (GT/GC) education. METHODS: Patients diagnosed with cancer between the ages of 18 and 39 and health care providers (HCPs) who treat AYA cancer patients were recruited from a single institution. Qualitative interviews explored AYA patients’ and HCPs’ concerns regarding their experiences discussing genetics and FP. RESULTS: The majority of patients (n = 17) were female (59%), and the majority of HCPs (n = 18) were male (67%). Overall, participants had differing perceptions of FP and GT/GC-related information provided during the clinical visit. Patients indicated initiating the conversation about FP and did not recall HCPs discussing GT/GC with them. HCPs indicated patients were often overwhelmed with too much information and comprehension of this discussion is limited. HCPs also felt patients’ emotions/beliefs determined their information-seeking behavior specific to FP and GT/GC. Participants felt educational materials should be developed and delivered in a video format depicting a patient–provider interaction or patient testimonial. CONCLUSION: AYA patients are often overwhelmed by a cancer diagnosis; the complexity/volume of information regarding FP and GT/GC may hinder understanding and decision-making about family building. Educational materials that help patients understand what questions to ask HCPs about FP and GT/GC should be developed to improve knowledge, psychosocial well-being, and future family building decisions.

PURPOSE The primary aim of this phase III randomized trial was to test whether the addition of vincristine, topotecan, and cyclophosphamide (VTC) to interval compressed chemotherapy improved survival outcomes for patients with previously untreated nonmetastatic Ewing sarcoma. METHODS Patients were randomly assigned to receive standard five-drug interval compressed chemotherapy (regimen A) for 17 cycles or experimental therapy with five cycles of VTC within the 17 cycles (regimen B). Patients were stratified by age at diagnosis (< 18 years and ≥18 years) and tumor site (pelvic bone, nonpelvic bone, and extraosseous). Tumor volume at diagnosis was categorized as < 200 mL or ≥ 200 mL. Local control occurred following six cycles. Histologic response was categorized as no viable or any viable tumor. Event-free survival (EFS) and overall survival (OS) were compared between randomized groups with stratified log-rank tests. RESULTS Of 642 enrolled patients, 309 eligible patients received standard and 320 received experimental therapy. The 5-year EFS and OS were 78% and 87%, respectively. There was no difference in survival outcomes between randomized groups (5-year EFS regimen A v regimen B, 78% v 79%; P = .192; 5-year OS 86% v 88%; P = .159). Age and primary site did not affect the risk of an EFS event. However, age ≥ 18 years was associated with an increased risk of death at 5 years (hazard ratio 1.84; 95% CI, 1.15 to 2.96; P = .009). The 5-year EFS rates for patients with pelvic, nonpelvic bone, and extraosseous primary tumors were 75%, 78%, and 85%, respectively. Tumor volume ≥ 200 mL was significantly associated with lower EFS. CONCLUSION While VTC added to five-drug interval compressed chemotherapy did not improve survival, these outcomes represent the best survival estimates to date for patients with previously untreated nonmetastatic Ewing sarcoma.

Seven Children’s Oncology Group phase 2 trials for patients with relapsed/progressive solid tumors were analyzed to estimate the event-free survival (EFS) for relapsed/progressive Ewing sarcoma. One hundred twenty-eight Ewing sarcoma patients were enrolled and 124 events occurred. The 6-month EFS was 12.7%, demonstrating the poor outcome of these patients. Only docetaxel achieved its protocol-specified radiographic response rate for activity; however, the EFS for docetaxel was similar to other agents, indicating that a higher radiographic response rate may not translate into superior disease control. This EFS benchmark could be utilized as an additional endpoint in trials for recurrent Ewing sarcoma.

Patients who are diagnosed with osteosarcoma (OS) today receive the same therapy that patients have received over the last 4 decades. Extensive efforts to identify more effective or less toxic regimens have proved disappointing. As we enter a postgenomic era in which we now recognize OS not as a cancer of mutations but as one defined by p53 loss, chromosomal complexity, copy number alteration, and profound heterogeneity, emerging threads of discovery leave many hopeful that an improving understanding of biology will drive discoveries that improve clinical care. Under the organization of the Bone Tumor Biology Committee of the Children's Oncology Group, a team of clinicians and scientists sought to define the state of the science and to identify questions that, if answered, have the greatest potential to drive fundamental clinical advances. Having discussed these questions in a series of meetings, each led by invited experts, we distilled these conversations into a series of seven Provocative Questions. These include questions about the molecular events that trigger oncogenesis, the genomic and epigenomic drivers of disease, the biology of lung metastasis, research models that best predict clinical outcomes, and processes for translating findings into clinical trials. Here, we briefly present each Provocative Question, review the current scientific evidence, note the immediate opportunities, and speculate on the impact that answered questions might have on the field. We do so with an intent to provide a framework around which investigators can build programs and collaborations to tackle the hardest problems and to establish research priorities for those developing policies and providing funding.

Background We performed a randomized phase 3 study of trabectedin versus dacarbazine in previously‐treated patients with liposarcoma/leiomyosarcoma (LPS/LMS). Methods Patients were randomized 2:1 to trabectedin (n = 384) or dacarbazine (n = 193) administered intravenously every 3 weeks. The primary objective was overall survival (OS). Secondary objectives were progression‐free survival, objective response rate, safety, and patient‐reported outcomes, all previously reported and demonstrating superior disease control with trabectedin. Results of the final OS analysis in preplanned subgroups of patients with LPS/LMS are presented. Results At the time of the final OS analysis, 577 patients had been assigned randomly, including 423 (73%) with LMS and 154 (27%) with LPS. The median duration of treatment exposure was higher in the trabectedin arm compared with the dacarbazine arm (4 vs 2 cycles), as was the proportion of patients receiving an extended number of therapy courses (≥6 cycles: 42% vs 22%). This pattern was consistent across histological subgroups: the median number of treatment cycles (4 vs 2 for both subgroups) and proportion of patients with ≥6 treatment cycles (LMS, 43% vs 24%; LPS, 40% vs 16%). Despite improved disease control by trabectedin, no improvement in OS was observed; the final median OS for trabectedin versus dacarbazine was 13.7 versus 13.1 months (P = .49). Sensitivity analyses of OS suggest confounding by post‐study anticancer therapies, which were utilized in most patients in both treatment arms (71% vs 69%, respectively). Conclusion The final OS results demonstrated comparable survival between LPS/LMS patients receiving trabectedin or dacarbazine, which is consistent with the interim analysis results. Both LPS and LMS demonstrated improved disease control with trabectedin., A final analysis of overall survival demonstrates comparable results between patients with liposarcoma/leiomyosarcoma receiving trabectedin or dacarbazine, which is consistent with interim analysis results. Both liposarcoma and leiomyosarcoma show improved disease control with trabectedin.

PURPOSE SARC024 is a phase II clinical trial of the multikinase inhibitor regorafenib in specific sarcoma subtypes, including advanced osteosarcoma. We hypothesized that regorafenib would improve progression-free survival (PFS) in patients with sarcoma and report the results of the osteosarcoma cohort. PATIENTS AND METHODS This trial enrolled patients with progressive metastatic osteosarcoma with measurable disease by RECIST who had received at least one prior line of therapy. Patients were randomly assigned at a ratio of one to one to regorafenib or placebo. Crossover was allowed at time of disease progression. PFS was the primary end point of the study, which was powered to detect a difference of at least 3 months in median PFS. RESULTS Forty-two patients from 12 centers were enrolled between September 2014 and May 2018. Median age was 37 years (range, 18 to 76 years). Patients had received an average of 2.3 prior therapy regimens. Ten patients receiving placebo crossed over to active drug at time of progression. Study enrollment was stopped early, after a data safety monitoring committee review. Median PFS was significantly improved with regorafenib versus placebo: 3.6 months (95% CI, 2.0 to 7.6 months) versus 1.7 months (95% CI, 1.2 to 1.8 months), respectively (hazard ratio, 0.42; 95% CI, 0.21 to 0.85; P = .017). In the context of the crossover design, there was no statistically significant difference in overall survival. Fourteen (64%) of 22 patients initially randomly assigned to regorafenib experienced grade 3 to 4 events attributed to treatment, including one grade 4 colonic perforation. CONCLUSION The study met its primary end point, demonstrating activity of regorafenib in patients with progressive metastatic osteosarcoma. No new safety signals were observed. Regorafenib should be considered a treatment option for patients with relapsed metastatic osteosarcoma.

PURPOSE: Healthcare providers (HCPs) and other staff at a comprehensive Cancer Center were interviewed on how to best implement a patient navigator position when working with adolescents and young adults (AYA) with cancer. Research objectives included assessing staff perceptions of (a) barriers to optimal care for AYA, (b) roles and responsibilities for a patient navigator, and (c) training needed for future patient navigators. METHODS: Semi-structured interviews were conducted with 17 staff members providing care to AYA. Verbatim transcripts were hand-coded using inductive content analysis. RESULTS: Roles and responsibilities of a patient navigator were described as needing to coordinate services, be knowledgeable of resources inside and outside the Cancer Center, provide emotional support, advocate for AYA, assist with financial and insurance issues, and serving as the first point of contact. CONCLUSIONS: Staff serving AYA reported the desired roles and training they wished a patient navigator to possess. This study contributes to the literature by conducting stakeholder assessment of the goals and roles of an AYA patient navigator (PN). PN positions should be adapted to the workflow and ethos of the institution.

ObjectiveIn the USA, the increase in state-sanctioned medical and recreational cannabis consumption means more young adults (YA) with cancer are using cannabis. Data and information are needed to characterise this use and frame much needed discussions about the role of cannabis in cancer care. To that end, this study’s objective was to describe consumption of cannabis in YA with cancer.MethodsFour hundred seventy-six patients with cancer ages 18–39 years at a large comprehensive cancer centre responded to a survey about their cannabis consumption. The survey was administered online between July 2019 and June 2020, and respondents were anonymous.ResultsFifty-two per cent (n=247) of respondents endorsed use within the last year; of these, half reported using cannabis prior to their diagnosis. Consumption was about equally distributed between smoking/inhalation and eating/drinking cannabis products. Seventy-five per cent of consumers used cannabis at least weekly. Top five primary reasons for use were pain, anxiety, nausea, sleep and recreation. More frequent consumption was associated with greater perceived improvement in certain symptoms. Cannabis products tended to be sourced from friends and family and information from non-medical sources. Most YA reported being comfortable discussing their consumption with providers.ConclusionsMany YA are using cannabis frequently to manage their cancer-related and treatment-related symptoms. Findings support the need for providers to consider cannabis use in treatment planning and symptom management with YA. Findings should help frame patient and provider discussions and herald much needed research on the effect of cannabis consumption on patient outcomes.

Purpose: Adolescent and young adult (AYA) oncology patients are less likely to enroll in clinical trials than pediatric patients. After two decades of effort to improve enrollments, challenges rema...

Osteosarcoma is the most common bone tumor in children and young adults. Metastatic and relapsed disease confer poor prognosis, and there have been no improvements in outcomes for several decades. The disease’s biological complexity, lack of drugs developed specifically for osteosarcoma, imperfect pre-clinical models, and limits of existing clinical trial designs have contributed to lack of progress. The Children’s Oncology Group Bone Tumor Committee established the New Agents for Osteosarcoma Task Force to identify and prioritize agents for inclusion in clinical trials. The group identified multi-targeted tyrosine kinase inhibitors, immunotherapies targeting B7-H3, CD47-SIRPα inhibitors, telaglenastat, and epigenetic modifiers as the top agents of interest. Only multi-targeted tyrosine kinase inhibitors met all criteria for front-line evaluation and have already been incorporated into an upcoming phase III study concept. The task force will continue to reassess identified agents of interest as new data becomes available and evaluate novel agents using this method.

Background Among sarcomas, which are rare cancers, many types are exceedingly rare; however, a definition of ultra-rare cancers has not been established. The problem of ultra-rare sarcomas is particularly relevant because they represent unique diseases, and their rarity poses major challenges for diagnosis, understanding disease biology, generating clinical evidence to support new drug development, and achieving formal authorization for novel therapies. Methods The Connective Tissue Oncology Society promoted a consensus effort in November 2019 to establish how to define ultra-rare sarcomas through expert consensus and epidemiologic data and to work out a comprehensive list of these diseases. The list of ultra-rare sarcomas was based on the 2020 World Health Organization classification, The incidence rates were estimated using the Information Network on Rare Cancers (RARECARENet) database and NETSARC (the French Sarcoma Network's clinical-pathologic registry). Incidence rates were further validated in collaboration with the Asian cancer registries of Japan, Korea, and Taiwan. Results It was agreed that the best criterion for a definition of ultra-rare sarcomas would be incidence. Ultra-rare sarcomas were defined as those with an incidence of approximately ≤1 per 1,000,000, to include those entities whose rarity renders them extremely difficult to conduct well powered, prospective clinical studies. On the basis of this threshold, a list of ultra-rare sarcomas was defined, which comprised 56 soft tissue sarcoma types and 21 bone sarcoma types. Conclusions Altogether, the incidence of ultra-rare sarcomas accounts for roughly 20% of all soft tissue and bone sarcomas. This confirms that the challenges inherent in ultra-rare sarcomas affect large numbers of patients.

PurposeSuccess of new cancer therapies relies strongly on effective selection of the target patient populations. We hypothesize that computational analysis of imaging data can be used for patient enrichment in clinical trials and hence aimed to establish the appropriate framework for this analysis.MethodsThis was tested among soft-tissue sarcoma (STS) patients accrued into a randomized clinical trial (SARC021) that evaluated the efficacy of evofosfamide (Evo), a hypoxia activated prodrug, in combination with doxorubicin (Dox). Notably, SARC021 failed to meet its overall survival (OS) objective. We tested whether a radiomic biomarker-driven inclusion/exclusion criterion could have been used to result in a significant treatment benefit of the Evo+Dox combination compared to Dox monotherapy. 164 radiomics features were extracted from 303 SARC021 patients with lung metastases, divided into training and test sets.ResultsA single radiomics feature, Short Run Emphasis, was identified as the most informative. Combined into a model along with histological classification and smoking history, an enriched subset (42%) of patients had longer OS in Evo+Dox vs. Dox groups [p=0.01, Hazard Ratio (HR) =0.57 (0.36-0.90)]. Applying the same model and threshold value in an independent test set confirmed the significant survival difference [p=0.002, HR=0.29 (0.13-0.63)], identifying patients most likely to benefit from doxorubicin alone.ConclusionThe study presents a first of its kind clinical-radiomic approach for patient enrichment in clinical trials. We show that, had an appropriate model been used for selective patient inclusion, SARC021 trial could have met its primary survival objective for patients with metastatic STS.

10042 Background: The combination of gemcitabine and docetaxel is often used to treat patients with recurrent osteosarcoma. A retrospective study of 35 such patients has reported an objective response rate of 17% and 4-month progression-free survival (PFS) of 56% with this combination (BMC Cancer 2016;16:280). Nab-paclitaxel is a nanoparticle taxane that has activity against osteosarcoma xenografts and may have less myelosuppression than docetaxel. The combination of gemcitabine and nab-paclitaxel is now frontline therapy for pancreatic cancer. We conducted a prospective multi-institutional phase II trial of this drug combination for patients with recurrent osteosarcoma. Methods: Patients with relapsed/refractory osteosarcoma with measurable disease and age ≥ 12 years and adequate organ function were included. A Simon’s two-stage design was used to identify a 4-month progression-free survival (PFS) of > 35%. Patients received nab-paclitaxel 125 mg/m2 and gemcitabine 1000 mg/m2 weekly x 3 in 4-week cycles. Results: Eighteen patients with a median age 16 years (range 12- 26) received a total of 56 total cycles.(median 2, range 1 - 12). The median number of prior treatment regimens was 3 (range 1-7). Two patients (11%) experienced a partial response, and 6 (33%) received more than 2 cycles. The 4-month PFS was 30% (95% CI 14-62 %). Six patients required dose reductions for neutropenia (n = 4), pleural effusion (1), or neuropathy (1). Two patients were removed from study secondary to neutropenia despite dose reduction and myeloid growth factor support, and one patient came off study due to severe peripheral edema. Conclusions: In this prospective study, the combination of gemcitabine and nab-paclitaxel administered on this schedule showed only limited activity for patients with heavily pretreated recurrent osteosarcoma. Toxicity led to dose modifications in 33% and discontinuation in 17% of patients. When compared to a historical retrospective study, the substitution of nab-paclitaxel for docetaxel did not appear to increase activity or decrease toxicity for this patient population. Clinical trial information: NCT02945800.