Sarcoma Trials Research Articles

Fragility index analysis of systemic therapy clinical trials in soft tissue sarcoma (STS).

11581 Background: The fragility index (FI) measures the robustness of randomized clinical trials (RCT) that have positive results based on statistical p-values. It estimates the minimum number of events that are needed to reverse the trial results from positive to negative. Here, we perform FI analysis on RCTs evaluating systemic treatments for STS. Methods: A systematic search of the Medline and Embase databases for RCTs in adults with advanced STS (Jan 1998 to Dec 2023) was conducted. Gastrointestinal stromal tumor trials were excluded. The FI framework was adapted to allow the use of time-to-event (TTE) outcomes – progression-free survival (PFS) or overall survival (OS) as previously described (Desnoyers et al 2021). Survival tables were reconstructed from published data on positive TTE outcomes, using the Parmar Toolkit. Positive secondary endpoints were used only if the primary endpoint was negative. The number of additional events that would result in a non-significant effect for the hazard ratio (HR) of the positive endpoint of each trial (FI) was calculated and expressed as a proportion of the size of the experimental arm (fragility quotient; FQ). The number of censored patients – those who withdrew consent or were lost to follow-up (Cn) was noted. Results: Among 47 RCTs, 16 (8 phase II; 8 phase III) trials had positive outcomes. The primary endpoint was positive and used for FI analysis in 11/16 trials (68.8%). PFS was the most common positive outcome, evaluated in 13 trials (81.3%). The median FI was 6 (range 2 – 52), with FI < 10 observed in 11 trials (68.8%). Median FQ was 7% (range 1 – 59%) and 10 trials (62.5%) had FQ < 10%. Among 14 trials that reported data, Cn was ≥ FI in 7 trials (50%). Only 2 of 4 trials (50%) that led to regulatory approval had FI > 10 or FQ > 10%. Of the other 2, one drug approval was subsequently withdrawn (Table). Conclusions: Most positive clinical trials in STS were fragile and their outcomes may be confounded by the level of censoring. Real-world evaluation of approved systemic therapies and value scales such as ESMO Magnitude of Clinical Benefit scale or ASCO value framework are needed to confirm clinical benefit of systemic treatments in STS.[Table: see text]

Randomized controlled, open-label, phase IIb/III study of lurbinectedin in combination with doxorubicin versus doxorubicin alone as first-line treatment in patients with metastatic leiomyosarcoma.

TPS11590 Background: Lurbinectedin (LUR) is a synthetic chemical entity structurally related to trabectedin that inhibits oncogenic transcription and is active in tumors addicted to transcription. Synergistic activity of the combination of LUR with Doxorubicin (DOX) was found in solid tumors. Preliminary results from two trials showed efficacy for LUR/DOX in anthracycline-naïve advanced Leiomyosarcoma (LMS) (1st or 2nd line) at different doses. In a phase 2 trial in soft tissue sarcoma (STS) patients (pts) (mostly with LMS: 12/20 pts), a combination of DOX 50 mg/m2 + LUR 2 mg/m2 Day (D)1 q3wk resulted in a response rate (RR) of 35% (4/7 LMS pts responding) and a disease control rate (DCR) at 24 wks of 40% (1). A phase 1b/2 trial in 10 advanced STS pts found a RR of 60% (5 were LMS, with 3 partial responses) treated at DOX 25 mg/m2 D1 or D1,D8 + LUR 3.2 mg/m2 D1 q3wk, (2). The promising results of these trials provide a rationale for further exploring this combination in a phase 2b/3 trial as first-line therapy for metastatic LMS (SaLuDo - NCT06088290). Methods: SaLuDo is a randomized, open-label study evaluating LUR in combination with DOX compared to DOX alone as first-line treatment of pts with metastatic LMS. The primary endpoint is progression-free survival (PFS) according to Independent Radiological committee (IRC). Secondary endpoints include overall survival, PFS according to Investigator assessment (IA), overall response rate, duration of response, and clinical benefit rate (according to IRC and IA), safety profile, patient-reported outcomes, pharmacokinetics, and exploratory pharmacogenomic analysis. Main inclusion criteria include age ≥ 18 years, confirmed diagnosis of metastatic LMS, and no prior systemic treatment for metastatic disease. Exclusion criteria include prior treatment with anthracyclines, lurbinectedin or trabectedin. The phase 2b part of the study will randomize approximately 120 pts into 3 arms (1:1:1): Control arm (DOX 75 mg/m2 D1 q3wk; experimental ARM A (DOX 50 mg/m2 D1 + LUR 2.2 mg/m2 D1 + 1ry GCSF prophylaxis q3wk), and experimental ARM B (DOX 25 mg/m2 D1 + LUR 3.2mg/m2 D1 + 1ry GCSF prophylaxis q3wk). Stratification will be done according to site of primary tumor (uterine vs. soft tissue), sites of metastatic disease (lung as unique site vs. other) and time from diagnosis to study entry (≤ 12 months vs. >12 months). One of the two experimental arms will be dropped out at the end of phase 2b. The study will then enter the phase 3 part and approximately 120 pts will be randomized 1:1 between the control arm and the selected experimental arm. An Independent Data Monitoring Committee will oversee the conduct of the study. The first patient was randomized in 09/2023. The phase 2b part of the study is ongoing and recruiting patients in Europe and the USA. 1. Cote EJC 2020; 126:21-32. 2. Cote. JCO 2023; 41: Abst 11507. Clinical trial information: NCT06088290 .

SY15-1 Reference centers and precision medicine trials in sarcoma

SY15-1 Reference centers and precision medicine trials in sarcoma

Novel Radioenhancer NBTXR3 Activated by Radiotherapy in Cisplatin-Ineligible Locally Advanced HNSCC Patients: Final Results of a Phase I Trial

New approaches are needed for frail or elderly patients with locally advanced head and neck squamous cell carcinoma (LA HNSCC) who are unfit to receive cisplatin with concurrent radiotherapy (RT). NBTXR3 is a first-in-class radioenhancer, composed of functionalized hafnium oxide nanoparticles, administered by a single intratumoral (IT) injection and activated by RT. NBTXR3 locally amplifies the anti-tumoral response of RT without adding toxicity to surrounding healthy tissue as shown in a randomized trial in soft tissue sarcoma. This two-part study: dose-escalation followed by the dose-expansion part reported here, evaluated the safety and preliminary efficacy for NBTXR3 activated by RT in elderly or frail patients ineligible to cisplatin. This trial enrolled patients who had previously untreated AJCC 8th Stage III-IVA or T3, T4 SCC of the oral cavity or oropharynx (OPC) ineligible to cisplatin. Eligible patients received a single IT injection of NBTXR3 at the recommended dose (22% of the baseline tumor volume) followed by RT (IMRT 70 Gy in 35 fractions). The primary objectives of the dose expansion part were to test the recommended dose, to confirm its safety, and obtain preliminary evidence of efficacy. The secondary objectives included the evaluation of progression-free survival (PFS) and overall survival (OS). Fifty-sixpatients in the dose expansion part were treated from April 2019-January 2022; 44 patients were evaluable for objective tumor response. In the all-treated population, median age was 71.9 years. 64.3% had age-adjusted Charlson Comorbidity Index scores ≥4, 55.4% had OPC (45.2% HPV+) and 80% had T3-4. Median injected volume of NBTXR3 was 13.6 [0.5-57.1] mL. Grade ≥ 3 adverse events reported as potentially related to NBTXR3 or to injection procedure were 1.2% and 0.4% of all AEs reported, respectively. In the evaluable population, the best objective response rate of the NBTXR3 injected lesion was 81.8% with a complete response rate of 63.6%. The best overall response rate (injected and non-injected lesions) was 79.5%. Final analyses on PFS and OS with long-term follow-up will be presented. NBTXR3 IT injection followed by activation with RT was confirmed to be feasible and well tolerated in elderly or frail patients with LA HNSSC and significant comorbidities. The high rate of best overall response suggests that NBTXR3+RT is effective in this elderly population ineligible to cisplatin with a high unmet medical need. These results support our ongoing phase III study comparing NBTXR3/RT ± cetuximab vs. RT ± cetuximab in platinum-based chemotherapy ineligible elderly patients with LA-HNSCC: NANORAY 312 (NCIT04892173).

QTPI: A quasi-toxicity probability interval design for phase I trials with multiple-grade toxicities.

The common terminology criteria for adverse events by the National Cancer Institute has greatly facilitated the revolution of drug development and an increasing number of Phase I trials have started to collect multiple-grade toxicity endpoints. Appropriate and yet transparent Phase I statistical designs for multiple-grade toxicities are therefore in great needs. In this article, we propose a quasi-toxicity probability interval (qTPI) design that incorporates a quasi-continuous measure of the toxicity probability () into the Bayesian theoretic framework of the interval based designs. Multiple-grade toxicity outcomes of each patient are mapped to according to a severity weight matrix. Dose-toxicity curve underlying the dosing decisions in the qTPI design is continuously updated using accumulating trial data. Numerical simulations investigating the operating characteristics of qTPI show that qTPI achieved better safety, accuracy and reliability compared to designs that rely on binary toxicity data. Furthermore, parameter elicitation in qTPI is simple and does not involve multiple hypothetical cohorts specification. Finally, a hypothetical soft tissue sarcoma trial with six toxicity types and grade 0 to grade 4 severity grades is illustrated with patient-by-patient dose allocation under the qTPI design.

A phase II study of cabozantinib and temozolomide in patients with unresectable or metastatic leiomyosarcoma and other soft tissue sarcomas.

11505 Background: Potentiation of chemotherapy, without increased toxicity, to improve outcome is an area of interest. Preclinical and clinical evidence shows simultaneous utilization of antiangiogenic agents and chemotherapy have a synergistic effect. We hypothesized that the dual targeting of VEGF and c-MET pathways with cabozantinib (CAB) would result in clinical benefit for patients with soft tissue sarcoma (STS) when combined with temozolomide (TMZ), an alkylating agent. Utilization of CAB/TMZ is anticipated to produce a synergistic antitumor effect worthwhile to explore in STS. Methods: A multicenter phase II study of CAB/TMZ in patients with unresectable/metastatic leiomyosarcoma (LMS) and other STS was conducted by the Midwest Sarcoma Trials Partnership. Age ≥ 18, adequate performance status, organ function, measurable disease (RECIST 1.1), and 0-5 prior chemotherapy regimens were required. CAB 40 mg PO daily plus TMZ 150-200 mg/m2 PO 1-5 days were given in 28-day cycles until disease progression or unacceptable toxicity. Patients enrolled in 2 cohorts: 1. Uterine and non-uterine LMS 2. Other STS. The first 14 subjects to be enrolled in the study in either cohort served as a safety lead in. The primary endpoint was progression-free rate (PFR) at 12 weeks for cohort 1. Secondary endpoints include overall response rate (ORR), clinical benefit rate, median progression-free survival (PFS), overall survival, and safety and tolerability. The exploratory endpoint was to estimate the correlation of PFR and OS to expression levels of VEGF, amongst others. A Simon 2-stage design was used. Results: A total of 42 patients were enrolled in Cohort 1, and 30 in Cohort 2, across 5 sites. For Cohort 1, median age was 59 years (range 35-86), 85.7% were non-Hispanic, 73.8% were female, 61.9% had ECOG of 0. The PFR at 12 weeks was 45.9% (for 37 evaluable patient) with a median PFS of 6.4 months (95% CI 4.6-6.7). Five PR were observed for an ORR of 13.5%. For Cohort 2, median age was 63 (20-86), 83.3% were non-Hispanic, 36.7% were female, 53.3% had ECOG of 0. The PFR at 12 weeks was 50% (for 28 evaluable patients) with a median PFS of 3.2 months (95% CI 1.4-4.6). One PR was observed. Reported grade 3-4 adverse events attributed to one or both intervention drugs affecting ≥10% of patients (n = 70) included hypertension (10%), decreased neutrophils (18.7%), decreased platelets (31%). Conclusions: The combination therapy of CAB/TMZ in patients with unresectable or metastatic LMS exceeded its primary endpoint with a PFR at 12 weeks > 39%. The PFS of 6.4 months in Cohort 1 exceeds rates achieved with second line tyrosine kinase inhibitors (TKIs) and alkylators in LMS patients. Treatment was feasible and did not reveal any previously unreported toxicities. The combination with CAB with TMZ demonstrated meaningful clinical benefit and is worth further exploration in LMS. Clinical trial information: NCT04200443 .

Accrual of adolescents and young adults (AYA) into cancer clinical trials in Canada.

e13598 Background: Historically, accrual rates of AYA (aged 16-39) to cancer clinical trials have been low. This is suggested to contribute to lesser improvements in their outcomes compared with older and younger populations. We sought to describe the impact of collaborative initiatives launched by the Canadian Cancer Trials Group (CCTG), NCTN and C17 to address this. Methods: All CCTG trials open to accrual from 01/01/2004 to 31/12/2022 were evaluated. Trials with eligibility criteria limited to age > 39, or for which CCTG did not have access to individual patient data on age, were excluded. Accrual rates were assessed by age (<30, 30-39, >40 yrs), cancer type, and compared with 2022 Canadian Cancer Society (CCS) prevalence data. Results: 379 studies were open to accrual. 21 trials were excluded as they had no patients aged 16-39 within their inclusion criteria. 2 trials were excluded as they were either COVID related or a trial sub-study. 230 trials were excluded owing to patient age data being unavailable to CCTG. 126 CCTG and NCTN led trials were included. They involved the following disease sites: brain (3), breast (13), GI (12), GU (11), gynecology (6), head & neck (3), hematology (10), lung (11), melanoma (4), sarcoma (2) novel investigational agents (45) and symptom control (6) – the latter two spanned multiple tumor types. Patients aged 16-18 were excluded from many trials limiting accrual opportunities in this subgroup. AYA patients were recruited into trials at a higher level than expected by prevalence data except for brain, lung and head & neck patients. This may be due to younger, fitter patients being recruited onto trials. GU trials, hematology and sarcoma trials recruited better than expected as there were trials geared to diseases common in younger individuals (e.g. germ cell cancers) and incorporating intensive therapy e.g. stem cell transplantation in lymphoma. 3.5% of patients accrued on trials were <40 in 2004-2013 c.f. 8.7% of patients 2014-2022. Conclusions: Limited data is available on AYA aged 16-18 due to trial entry criteria. Currently, most CCTG trials include patients aged ≥14. Trial accrual in the AYA population was higher than predicted by CCS data indicating that clinical trials are acceptable to AYA patients. This supports ongoing efforts to improve trial access to AYA. [Table: see text]

The Midwest Sarcoma Trials Partnership: Bridging Academic and Community Networks in a Collaborative Approach to Sarcoma.

The treatment of sarcoma necessitates a collaborative approach, given its rarity and complex management. At a single institution, multidisciplinary teams of specialists determine and execute treatment plans involving surgical, radiation, and medical management. Treatment guidelines for systemic therapies in advanced or nonresectable soft tissue sarcoma have advanced in recent years as new immunotherapies and targeted therapies become available. Collaboration between institutions is necessary to facilitate accrual to clinical trials. Here, we describe the success of the Midwest Sarcoma Trials Partnership (MWSTP) in creating a network encompassing large academic centers and local community sites. We propose a new model utilizing online platforms to expand the reach of clinical expertise for the treatment of advanced soft tissue sarcoma.

Informed consent in clinical trials: Implementing methods to improve patient understanding in cancer research—A quality improvement initiative in a sarcoma trials unit.

335 Background: Clinical trials are considered the cornerstone of improving outcomes for cancer patients. The understanding of an individual patient of the trial on which they are enrolled can vary significantly, with some studies demonstrating poor patient understanding of their involvement in trials. This exploratory study aimed to improve patient understanding of clinical trials and patient experience of the informed consent process by implementing measures to present complex trial information in alternative formats. Methods: The project was undertaken in a sarcoma trials unit in a specialist cancer treatment centre. Baseline knowledge was assessed using an adapted version of the Quality of Informed Consent (QuIC) questionnaire. A decision-aid was created following focus group discussions with stakeholders, focussing on key trial questions for patients, such as consent, the research description, risks, benefits, and alternatives to the trial. A patient education video was produced by the research team, explaining general aspects of clinical trials in patient-friendly language. The decision-aids and videos were distributed during the informed consent process of trial recruitment over a 12-week period. The patient group was assessed with post-intervention questionnaires. Statistical analysis was descriptive due to the small numbers. Results: Thirty sarcoma patients participated in the project, including baseline assessment of 15 patients previously enrolled on study, and 15 patients considering participation in a trial who underwent the intervention. 100% (n = 15) of the interventional group found the video and decision-aid useful. 60% (n = 18) of patients had a university level education, indicating a well-educated population. A pre- and post-intervention comparison demonstrated an improved understanding of 10 key elements of clinical trial information as shown in Table. Conclusions: Our exploratory study has shown that patient education tools including decision-aids and patient videos can be successfully implemented to help improve patient understanding of clinical trial information and may be of benefit in other trials units. Further larger studies are required to confirm these findings.[Table: see text]

Patient reported quality of life in young adults with sarcoma receiving care at a sarcoma center.

BackgroundSarcomas are a diverse group of neoplasms that vary greatly in clinical presentation and responsiveness to treatment. Given the differences in the sites of involvement, rarity, and treatment modality, a multidisciplinary approach is required. Previous literature suggests patients with sarcoma suffer from poorer quality of life (QoL) especially physical and functional wellbeing. Adolescent and young adult (AYA) patients are an underrepresented population in cancer research and have differing factors influencing QoL.MethodsRetrospective analysis of Young Adult patients (age 18–39) enrolled in the Sarcoma Tissue Repository at University of Iowa. QoL was assessed using the self-report FACT-G questionnaire at enrollment and 12 months post-diagnosis; overall scores and the 4 wellbeing subscales (Physical, Emotional, Social, Functional) were calculated. Linear mixed effects models were used to measure the association between the rate of change in FACT-G subscale scores and baseline clinical, comorbidity, and treatment characteristics.Results49 patients were identified. 57.1% of patients had a malignancy involving an extremity. Mean FACT-G scores of overall wellbeing improved from baseline to 12 months (76.4 vs. 85.4, p < 0.01). Social and emotional wellbeing did not differ significantly between baseline and 12 months. Physical wellbeing (18.8 vs. 23.9, p < 0.01) and functional wellbeing (16.8 vs. 20.0, p< 0.01) scores improved from baseline to 12 months. No difference was seen for FACT-G overall scores for age, sex, laterality, marital status, performance status, having children, clinical stage, limb surgery, chemotherapy, or tumor size. A difference was demonstrated in physical wellbeing scores for patients with baseline limitation (ECOG 1-3) compared to those with no baseline limitation (ECOG 0) (p = 0.03). A difference was demonstrated in social wellbeing based on anatomical site (p = 0.02).ConclusionYoung adults with sarcoma treated at a tertiary center had improvements in overall reported QoL at 12 months from diagnosis. Overall baseline QoL scores on FACT-G were lower than the general adult population for YA patients with sarcoma but at 12 months became in line with general population norms. The improvements seen merit further investigation to evaluate how these change over the continuum of care. Quality of life changes may be useful outcomes of interest in sarcoma trials.

Abstract IA007: B cell immunity generation in tertiary lymphoid structures, a major determinant of sarcoma immune response to immunotherapy

Abstract The presence of tertiary lymphoid structures (TLSs) and a high intratumoral density of B lymphocytes have been associated with improved survival in several tumor types. We investigated the impact of TLS on responses to immunotherapy and, analyzing a large-scale retrospective analysis of three independent cohorts of patients with cancer, including sarcomas, who were treated with anti-PD-1 or anti-PD-L1 antibodies, we showed that the presence of mature TLSs was associated with improved objective response rates, progression-free survival and overall survival, independent of PD-L1 expression status and CD8+T cell density. To decipher the role of B cells in such responses, we performed spatial transcriptomics and examined the nature of B cell responses within TLS structure. B cells were enriched in TLS, and therein we could identify all B cell maturation stages toward plasma cell (PC) formation. B cell repertoire analysis revealed clonal diversification, selection, expansion in TLS and the presence of full mature clonotypes at distance. In TLS+ tumors, IgG producing PCs disseminated into the tumor beds along fibroblastic tracks. TLS+ tumors exhibited high frequencies of IgG-producing PCs and IgG-stained and apoptic malignant cells, suggestive of anti-tumor effector activity. We validated these findings in a prospective trial in metastatic Soft Tissue Sarcoma (STS) bearing patients. PEMBROSARC is a multi-cohort phase II study of pembrolizumab combined with low-dose cyclophosphamide in patients with advanced STS. The 6-months non-progressive rate (NPR) and the objective response rates previously reported in cohorts including all comers were 4.9% and 2.4%, respectively. In the cohort enrolling patients selected based on the presence of TLS, the 6-month NPR was 40% and the objective response rate was 30%. Exploratory analyses reveled that infiltration by IgG antibody-producing plasma cells was associated with improved clinical outcome as well as the presence of IgG antibodies on tumor cells. Altogether, these results establish that maturation, selection and amplification of B cells in intratumoral TLSs results in Plasma Cells generation which may produce anti-tumor antibodies. The latter may amplify in situ antitumor immune responses leading to better therapeutic responses to immunotherapy. Citation Format: Wolf H. Fridman. B cell immunity generation in tertiary lymphoid structures, a major determinant of sarcoma immune response to immunotherapy [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr IA007.

Abstract A038: Enrollment of pediatric and adolescent patients with MAGE-A4+ advanced synovial sarcoma into cohort 2 of SPEARHEAD-1: a phase 2 trial of afamitresgene autoleucel (“afami-cel” [formerly ADP-A2M4

Abstract Background: Afami-cel is an autologous, specific peptide enhanced affinity receptor T-cell therapy genetically engineered to target MAGE-A4+ solid tumors in HLA-A*02+ patients. SPEARHEAD-1 (NCT04044768) is a Phase 2, two-cohort, single-arm, open-label trial evaluating afami-cel in patients with advanced/metastatic synovial sarcoma or myxoid/round cell liposarcoma (MRCLS) and is the largest trial in metastatic synovial sarcoma to date. Preliminary data from Cohort 1 in 47 heavily pre-treated patients aged 16–75 years from 22 centers in North America and Europe, showed an overall response rate (ORR) per independent review of 34.0% (14/39 [35.9%] in synovial sarcoma; 2/8 [25%] in MRCLS) and a favorable benefit–risk profile with mainly low-grade cytokine release syndrome and tolerable/reversible hematologic toxicities.1 The reported ORR in synovial sarcoma in Cohort 1 was higher than reported ORRs for current standard-of-care therapies, such as pazopanib and trabectedin, in the second-line metastatic setting.2 As synovial sarcoma is the most common malignant nonrhabdomyosarcoma soft-tissue sarcoma in children and adolescents with few treatment options, especially for recurrent disease, the trial opened a second cohort to allow enrollment of pediatric patients with MAGE-A4+ synovial sarcoma who experienced disease progression post first-line chemotherapy, and to better understand MAGE-A4 tumor expression in children. Methods: Cohort 2 of the SPEARHEAD-1 trial is enrolling patients with advanced synovial sarcoma who are at least 10 years old and weigh at least 40 kg. The planned enrollment is 45 patients, including up to 13 children, to enable a pooled analysis of ORR in &amp;gt;90 patients across Cohorts 1 and 2. HLA and MAGE-A4+ screening in Cohort 2 is conducted at a central laboratory using the same method as Cohort 1; MAGE-A4 testing is done using a clinical trial assay. All patients enrolled in Cohort 2 undergo apheresis and their isolated T-cells are then transduced with the MAGE-A4c1032 TCR using a lentivirus vector, followed by ex vivo expansion. Prior to afami-cel infusion of 1–10 × 109 transduced T-cells, patients will receive lymphodepleting chemotherapy consisting of fludarabine (30 mg/m2/day for 4 days) and cyclophosphamide (600 mg/m2/day for 3 days). Disease will be assessed by independent review per RECIST v1.1 using computerized tomography or magnetic resonance imaging at weeks 4, 8, 12, 16, 24, and every 2 months thereafter until confirmed disease progression. Patients enter long-term follow-up for 15 years. 1. Van Tine BA, et al. Paper 30: CTOS 2021; Virtual 2. Carroll C, et al. Cancer Res 2021;81(13_Suppl): Abstract nr 2630. Citation Format: Colin Lunt, Sandra P. D’Angelo, Albiruni Ryan Abdul Razak, Michael J. Wagner, Brian A. Van Tine, Kristen Ganjoo, Jean-Yves Blay, Dejka M. Araujo, Mark Agulnik, John W. Glod, Erin Van Winkle, Erica Elefant, Swethajit Biswas, Dennis Williams, Axel Le Cesne. Enrollment of pediatric and adolescent patients with MAGE-A4+ advanced synovial sarcoma into cohort 2 of SPEARHEAD-1: a phase 2 trial of afamitresgene autoleucel (“afami-cel” [formerly ADP-A2M4]) [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr A038.

Optimizing Histology-Specific Clinical Trials in Soft-Tissue Sarcoma—Are We There Yet?

Optimizing Histology-Specific Clinical Trials in Soft-Tissue Sarcoma—Are We There Yet?

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

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

Presence of immune infiltrates, increased expression of transposable elements, and viral response pathways in sarcoma associate with response to checkpoint inhibition.

11510 Background: Response to checkpoint inhibition (CPI) in sarcoma is overall low and varies between and within subtypes. Understanding tumor intrinsic determinants of this response may improve efficacy and patient selection. The de-repression of transposable elements (TEs), which are epigenetically silenced repetitive DNA elements of viral origin, is linked to anti-tumor immunity through an antiviral inflammatory response. We hypothesize that baseline expression of TEs and epigenetic regulators correlates with overall response rate (ORR) in sarcoma CPI clinical trials. Methods: This is a retrospective analysis of bulk RNA-sequencing data from pre-treatment biopsies of patients on CPI trials in sarcoma (pembrolizumab plus talimogene laherparepvec, nivolumab plus bempegaldesleukin, and pembrolizumab plus epacadostat). Sixty-seven samples from unique patients representing 12 subtypes were analyzed. The MCP counter deconvolution method and unsupervised clustering were used to group samples by immune phenotypes resulting in immune ‘hot’ and ‘cold’ clusters. ORR was defined by RECIST. To determine if baseline expression of TEs and epigenetic regulators significantly predicted immune types, we implemented a lasso penalized logistic regression. Results: Immune ‘hot’ tumors were characterized by increased immune infiltrates including CD8+ T-cells, B-cells, and NK cells vs ‘cold’ tumors. Patients with ‘hot’ vs ‘cold’ tumors had an ORR of 30.5% (11/36) vs. 3.2% (1/31) (p = 0.003; chi-squared). The best predictors of ‘hot vs ‘cold’ was the increased expression of multiple TE families including MER45A, MER57F, and LTR21B (respective lasso coefficients, 0.27, 0.07, and 0.07). Expression of IKZF1, a chromatin-interacting transcription factor, was also predictive (lasso coefficient, 0.35) and increased expression correlated with improved ORR (p = 0.003; unpaired t-test). TE and IKFZ1 expression was significantly correlated with CD8+ T-cell signaling and antiviral response pathways such as cGAS-STING (MER57F, r2= 0.43, padj = 1.75E-4; IKZF1, r2= 0.63, padj = 6.28E-9) and type II interferon (MER57F, r2= 0.67, padj = 2.51E-10; IKZF1, r2= 0.60, padj = 7.19E-8). Increased expression of cGAS-STING (p = 3.9E-4; unpaired t-test) and type II interferon pathways (p = 1.89E-10; unpaired t-test) was significant in ‘hot’ tumors. Conclusions: Immune ‘hot’ baseline immune profiles of sarcoma are associated with improved ORR to CPI and with increased expression of TEs and IKZF1. These differences in gene expression correlate with increased inflammatory signaling, which suggests a response to TE-encoded viral-like sequences that are typically epigenetically silenced. Induction of TE de-repression and IKZF1 expression through epigenetic targeting warrants pre-clinical investigation as a strategy to promote CPI response in sarcomas.

Challenges of Systemic Therapy Investigations for Bone Sarcomas.

Bone sarcoma is a rare component of malignant solid tumors that accounts for only ~0.2% of malignancies. Bone sarcomas present various histological types, and genomic mutations differ markedly by the histological types. Although there are vast mutations in various bone sarcomas, most of them are non-actionable, and even potential targetable mutations that are actionable targets in other malignancies have not shown the appropriate responses in clinical trials for bone sarcomas. Investigations of new systemic therapy, including molecular targeted therapies for bone sarcomas, have thus not progressed like those for other solid tumors. Another problem is that high rates of pediatric/adolescent and young adult patients have bone sarcomas such as osteosarcoma, and patient recruitment for clinical trials (especially randomized trials) is challenging. For pediatric patients, evaluations of tolerability and appropriate dose modifications of new drugs are needed, as their findings could provide the threshold for investigating new drugs for bone sarcomas. To solve these problems, improvements in registry systems, real world data, and pediatric extrapolation have been attempted. We review the issues regarding targeted drug investigations for bone sarcomas, focusing on the current clinical evidence and efforts to resolve these issues.

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

BackgroundThe prognosis of patients with advanced soft-tissue sarcomas (STS) remains dismal, and systemic therapeutic options are limited. Early phase trials are becoming increasingly safe and effective. This study aimed to identify the prognostic factors for progression-free survival (PFS).Patients and methodsThis retrospective analysis included all STS patients participating in early phase trials at Gustave Roussy and Léon Bérard between 1 January 2012 and 31 December 2020.ResultsOverall, 199 patients accounted for 214 inclusions in advanced STS. The most frequent histotypes were well-differentiated/dedifferentiated liposarcomas (n = 55), leiomyosarcomas (n = 53), synovial sarcomas (n = 22), undifferentiated pleomorphic sarcomas (n = 15), angiosarcomas (n = 12), and myxoid liposarcomas (n = 10). The median PFS was 2.8 months (95% confidence interval 2.7-4.1 months). The median PFS in the first, second, and later lines was 8.3, 5.4, and 2.6 months, respectively (P = 0.00015). The median PFS was 2.8 months in case of molecular screening, 4.1 months in case of histology-driven screening, and 1.6 months (P = 0.00014) in the absence of either screening modalities. In univariate analysis, histotype (P = 0.026), complex genomics (P = 0.008), number of prior lines (P < 0.001), prior anthracyclines (P < 0.001), number of metastatic sites (P = 0.003), liver metastasis (P < 0.001), lung metastasis (P < 0.001), absence of molecular or histology-driven screening (P < 0.001), first-in-human trials (P < 0.001), dose-escalation cohorts (P = 0.011), and Royal Marsden Hospital (RMH) score >1 (P < 0.001) were significantly associated with shorter PFS. In multivariate analysis, independent prognostic factors for shorter PFS were myxoid liposarcoma (P = 0.031), ≥2 prior lines of treatment (P = 0.033), liver metastasis (P = 0.007), and RMH score >2 (P = 0.006). Factors associated with improved PFS were leiomyosarcomas (P = 0.010), molecular screening (P = 0.025), and histology-driven screening (P = 0.010). The median overall survival rates were 36.3, 12.6, and 9.2 months in the first, second, and later lines, respectively (P = 0.0067). The grade 3-4 toxicity rate was 36%.ConclusionsEarly phase trials provide an active therapeutic option for STS, even in first-line settings. Molecular screening and histology-driven trials further improve the clinical benefit.

Current Status and Future Directions of Immunotherapies in Soft Tissue Sarcomas.

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

Radiomics in sarcoma trials: a complement to RECIST for patient assessment

Radiological imaging has a critical role in the diagnosis of sarcomas and in evaluating therapy response assessment. The current gold standard for response assessment in solid tumors is the Response Evaluation Criteria in Solid Tumors, which evaluates changes in tumor size as a surrogate endpoint for therapeutic efficacy. However, tumors may undergo necrosis, changes in vascularization or become cystic in response to therapy, with no significant volume changes; thus, size assessments alone may not be adequate. Such morphological changes may give rise to radiographic phenotypes that are not easily detected by human operators. Fortunately, recent advances in high-performance computing and machine learning algorithms have enabled deep analysis of radiological images to extract features that can provide richer information about intensity, shape, size or volume, and texture of tumor phenotypes. There is growing evidence to suggest that these image-derived or “radiomic features” are sensitive to biological processes such as necrosis and glucose metabolism. Thus, radiomics could prove to be a critical tool for assessing treatment response and may present an integral complement to existing response criteria, opening new avenues for patient assessment in sarcoma trials.

TP53 Mutation as a Prognostic and Predictive Marker in Sarcoma: Pooled Analysis of MOSCATO and ProfiLER Precision Medicine Trials.

Simple SummarySarcomas have a high recurrence rate and no validated genomic marker to guide decisions of peri-operative systemic treatments. We pooled two precision oncology trials in order to identify genomic markers prognostic and/or predictive of response to treatment with anthracyclines in sarcoma patients. Molecular analysis consisted of targeted next generation sequencing and comparative genomic hybridization array. TP53 mutations were the most frequent alteration, found in 20% of sarcomas. Disease-free survival of localized sarcomas was shorter in TP53 mutated sarcomas, both in our cohort and in The Cancer Genome Atlas database. Objective response rate to anthracycline-based chemotherapy was increased in TP53 mutated sarcomas, in localized and advanced settings in this pooled analysis. Post-validation, TP53 mutations may serve as a biomarker to assist decision of peri-operative anthracycline prescription.(1) Background: locally resected high-grade sarcomas relapse in 40% of cases. There is no prognostic or predictive genomic marker for response to peri-operative chemotherapy. (2) Methods: MOSCATO and ProfiLER are pan-tumor prospective precision medicine trials for advanced tumors. Molecular analysis in both trials comprised targeted next-generation sequencing and comparative genomic hybridization array. We investigated if molecular alterations identified in these trials in sarcomas were associated with disease-free survival (DFS) and response to anthracyclines. (3) Results: this analysis included 215 sarcomas, amongst which 53 leiomyosarcomas, 27 rhabdomyosarcomas, 20 undifferentiated pleomorphic sarcomas, and 17 liposarcomas. The most frequently altered gene was TP53 (46 mutations and eight deletions). There were 149 surgically resected localized sarcomas. Median DFS in TP53 wild type (WT), deleted, and mutated sarcomas was 16, 10, and 10 months, respectively (p = 0.028; deletions: HR = 1.55; 95% CI = 0.75–3.19; mutations: HR = 1.70; 95%CI = 1.13–2.64). In multivariate analysis, TP53 mutations remained associated with shorter DFS (p = 0.027; HR = 2.30; 95%CI = 1.10–4.82). There were 161 localized and advanced sarcomas evaluable for response to anthracyclines. Objective response rates were 35% and 55% in TP53 WT and mutated sarcomas, respectively (OR = 2.24; 95%CI = 1.01–5.03; p = 0.05). In multivariate analysis, TP53 mutations remained associated with increased response (OR = 3.24; 95%CI = 1.30–8.45; p = 0.01). (4) Conclusions: TP53 mutations are associated with shorter DFS and increased response to anthracyclines. Post-validation, these findings could assist in decision-making for peri-operative treatments.