Reed, Damon R.

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.

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.

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.

Abstract Trial Information Click here to access other published clinical trials. Lessons Learned The results from the liposarcoma cohort of SARC024 confirm previously published data and do not support the routine use of regorafenib in this patient population. Continued exploration of novel therapies, including combination approaches, is warranted for a patient population in whom limited treatment options exist. Background Regorafenib is a multitargeted kinase inhibitor with a kinase profile overlapping, but distinct from, pazopanib, an agent approved for recurrent and metastatic non-gastrointestinal stromal tumor (GIST), non-adipocytic soft tissue sarcoma. We conducted a randomized, phase II study of regorafenib versus placebo in refractory liposarcoma patients. Methods Patients with advanced or metastatic, treatment-refractory liposarcoma were randomized 1:1 to receive regorafenib 160 mg or placebo once daily (3 weeks on, 1 week off). Patients with well-differentiated liposarcoma only were excluded. Crossover for placebo was allowed upon progression. The primary endpoint was progression-free survival (PFS), according to RECIST version 1.1. Results Forty-eight subjects with liposarcoma (34 dedifferentiated, 12 myxoid/round cell, 2 pleomorphic) were enrolled. Median PFS was 1.87 (95% confidence interval [CI], 0.92–3.67) months for regorafenib versus 2.07 (95% CI, 1.64–3.44) months for placebo; stratified hazard ratio [HR], 0.85 (95% CI, 0.46, 1.58), p = .62. No responses were seen on regorafenib. One PR was observed on placebo. Median overall survival was 6.46 (95% CI, 4.16–23.48) months for regorafenib and 4.89 (95% CI, 3.02–9.77) months for placebo, stratified HR, 0.66 (95% CI, 0.31–1.40), p = .28). Treatment-related adverse events were similar to the known safety profile of regorafenib. Conclusion Regorafenib did not appear to improve PFS in treatment-refractory liposarcoma. No new significant safety signals were observed.

e19214 Background: ARST1321(PAZNTIS): A Phase II/III Randomized Trial of Preoperative Chemoradiation or Preoperative Radiation Plus or Minus Pazopanib (NCT02180867) was the first National Clinical Trials Network (NCTN) study co-developed by pediatric (COG) and adult (NRG Oncology) consortia anticipating enrollment of adolescent and young adult (AYA) cancer patients. ARST1321 had two treatment cohorts, enrolling patients ≥ 2 years of age to either chemotherapy (C) (chemoradiation ± pazopanib) or non-chemotherapy (NC) (radiation ± pazopanib) arms. It was anticipated adults would contribute the majority of enrollments on the NC arm based on prior enrollment patterns. While the C arm accrued as anticipated (with high enrollment of adults and children), the NC arm had low enrollment leading to premature closure. We report on AYA accrual (defined as 15-39 years) to the NC arm and a survey aiming to identify barriers to enrolling AYA patients onto ARST1321. Methods: Our survey was emailed to 161 adult, surgical, and radiation oncologists at large sarcoma centers. A link was sent to an online questionnaire via SurveyMonkey Inc. and responses were reviewed on their platform. Results: 33 patients enrolled on the ARST1321 NC arm, of which 24% were AYA. 25% of AYA enrollments were from non-COG adult cooperative groups. This trial arm was closed in October 2017 after 3.25 years of accrual below anticipated rates. The survey response rate was 31% with a 70% completion rate. Almost half of respondents were medical oncologists with most seeing 50-200 new sarcoma cases/year at an academic institution and 30% in a pediatric environment (divided equally between radiation and surgical oncologists). 70% of respondents have a joint collaboration with their pediatric oncology team with 23% having a joint clinic. 70% of respondents’ sites opened ARST1321 and anticipated 1-5 patients would be eligible for the NC cohort. However, 42% of respondents’ sites had zero patients enrolled on that arm. The most common reasons for not opening the study and/or not enrolling patients on the NC arm included: lack of interest, disagreement with the therapy, lack of a site investigator, premature study closure, patient/family decision, competing trials, insufficient reimbursement, and regulatory delays. Conclusions: Our survey highlights multiple barriers to enrollment of AYA onto cross-NCTN consortia clinical trials spanning the age spectrum. The information obtained will help inform investigators aiming to effectively design, enroll, and conduct similar trial efforts for AYA in the future.

11529 Background: Maximum tumor dimension > 8 cm. and large tumor volume have been reported to be adverse prognostic factors in patients with ES but have not been prospectively evaluated in the context of a phase 3 clinical trial with interval compressed chemotherapy. Methods: COG AEWS1031 (NCT01231906) was a randomized phase 3 clinical trial comparing interval compressed chemotherapy regimens in patients with newly diagnosed localized ES of bone and soft tissue. A correlative objective of AEWS1031 was to evaluate tumor size and volume as prognostic factors. Institution-reported dimensions of the primary tumor from baseline imaging were prospectively collected. For inclusion in this analysis, patients had to have at least 1 tumor dimension reported for tumor size analyses and dimensions in 3 axes for tumor volume analyses. Maximum dimension was dichotomized as less than vs. > / = 8cm. Tumor volume was dichotomized as less than vs. > / = 200 mL. Event-free (EFS) and overall survival (OS) from enrollment were calculated using Kaplan-Meier methods and compared between groups using a two-sided log-rank test. Hazard ratios (HR) and confidence intervals (CI) were calculated using the Cox model. Results: The 5-year EFS and OS of the 629 eligible patients was 78% (95% CI: 75-81%) and 87% (95% CI: 84-90%) respectively and there was no significant difference in both EFS and OS between the randomized interval compressed chemotherapy arms of AEWS1031. 590 of 629 (94%) patients were evaluable for maximum tumor dimension and 307 (52%) had tumors > / = 8 cm. Patients with tumors > / = 8 cm were at significantly increased risk for EFS events (p = 0.016) with estimated 5-year EFS of 73.7% (95% CI: 68.1 vs.78.4%) vs. 82.9% (95% CI 77.7-87.1%) for patients with tumors < 8 cm [HR: 1.53 (1.08-2.17)]. For tumor volume, 586 of 629 patients (93%) were evaluable and 180 (31%) had tumors > / = 200 mL. Patients with tumor volume > / = 200 mL were at significantly increased risk for EFS events (p = 0.003) with estimated 5-year EFS of 70% (95% CI: 62.3-76.4%) vs. 81.6% (95% CI: 77.2-85.2%) for patients with tumors < 200 mL [HR: 1.69 (1.2-2.39)]. Conclusions: Maximum tumor dimension and tumor volume as defined are both prognostic in patients with newly diagnosed localized ES treated with interval compressed chemotherapy. Clinical trial information: NCT01231906 .

10003 Background: Preclinical studies demonstrate synergistic anti-tumor activity by inhibiting mTOR and IGF-1R. This study evaluated the safety and efficacy of A12 and TEM in 3 chemo-refractory cohorts: IGF-1R (+) STS (Arm A), IGF-1R (+) bone (Arm B), and IGF-1R (-) bone and STS (Arm C). Methods: An optimal Simon 2 stage design was used for each arm. The primary end-point was progression free survival (PFS) at 12 weeks. Based on historical data, a 40% PFS rate was considered promising and a 20% PFS non-promising (type I/ II error, 0.05/0.10). ≥5 PFSs at 12 weeks were required in the first 19 and ≥16 PFSs were required in a total of 54 pts to consider each arm positive. Key eligibility: measurable disease (RECIST 1.1), age ≥18, 1- 4 priors, ECOG status 0-1. A12 (6 mg/kg) and TEM (25 mg) were administered IV weekly. Pre and post treatment tumor biopsies and plasma for IGF-1 and IGFBP3 were obtained. 20 Sarcoma Centers participated. Results: Starting in 02/2010, 383 pts were tested for IGF-1R by immunohistochemistry (IHC; 54% +) and 171 were treated: mean age 47 (range: 18-80), mean # priors 2.2 (range: 1-4). Grade 3/4 toxicities ≥10%: lymphopenia (12%), mucositis (10%). By intent to treat (ITT) analysis, each arm of the study achieved its primary 12 week PFS end-point (≥16 PFSs): Arm A: 18/56 (32%), Arm B: 19/50 (38%) (4 too early), Arm C: 27/63 (43%). The one-sided 95% CI for 12-week PFS is (0.22, 1), (0.27, 1), and (0.32, 1), respectively. By ITT the median PFS (95% CI) in weeks for each arm is 6.3 (5.9, 12.0), 11.0 (8.0, 18.0) and 11.6 (9.0, 17.9), respectively, and for chondro (n=18), Ewing’s (n=24), and osteo (n=23) only it is 22.6 (5.7, 40.9), 10.4 (5.7, 17.9) and 6.0 (6.0, 18.0), respectively. Westerns on 32 matched pair tumor biopsies indicate inhibition of IGF-1R, pAKT and pS6. Of biopsies on 7 IGF-1R (-) IHC pts (Arm C), 5 were IGF-1R (+) by western. Plasma biomarkers did not correlate with PFS. Conclusions: A12 and TEM met its primary end-point of improved PFS in pts with metastatic sarcoma. This effect was independent of IGF-1R status by IHC. These results support further clinical development of this combination in bone and STS.

11015 Background: Immune checkpoint inhibitors have demonstrated activity in multiple tumor types but their activity in soft tissue sarcomas remains limited. In the multicenter phase II study, SARC028, the anti-PD-1 antibody, P demonstrated objective responses that were largely restricted to UPS and LPS subtypes. We now report outcomes from 2 expansion cohorts of SARC 028 in advanced UPS and LPS. Methods: To further confirm the clinical activity of P in UPS and LPS, we enrolled an additional 30 pts in each of 2 expansion cohorts for a total of 40 UPS and 40 LPS pts. Primary endpoint was investigator-assessed response by RECIST v1.1. Secondary endpoints were safety, progression-free survival (PFS), 12-week PFS rate, and overall survival (OS). An ORR of 25% was considered clinically meaningful and < 10% was considered to show lack of efficacy. P was to be considered a success if 8 or more of 40 enrolled patients had a PR or better (1-sided α = 0.042, 82% power). Pts age ≥18 with advanced, refractory UPS or LPS received 200 mg of P IV every 3 weeks until progression or unacceptable toxicity. Results: Preliminary results from the first 10 pts in each of the UPS and LPS cohorts have been reported. We now present summary data after enrolling an additional 30 pts in each cohort. The ORR in the UPS cohort was 23% (9/40), with an additional 5/30 PRs observed in the expansion cohort (total 2 CRs, 7 PRs). In the LPS cohort, the ORR was 10% (4/39 evaluable pts), with an additional 2/30 PRs observed (total 4 PRs). Median PFS for the UPS group was 3 months [95% CI: 2, 5] and 2 months [95% CI: 2, 4] for the LPS group. 12-week PFS rate was 50% in UPS [95% CI: 35, 65] and 44% in LPS [95% CI: 28, 60]. The UPS group had a median OS of 12 months [95% CI: 7, 34] and 13 months [95% CI: 8, NR] for the LPS group. P was well tolerated with no unexpected toxicities. Conclusions: The UPS cohort achieved its primary endpoint, however the activity of P in UPS deserves further evaluation in a randomized study. The activity of P was not confirmed in the LPS cohort. Ongoing biomarker analyses may direct better patient selection and guide future combination strategies. Clinical trial information: NCT02301039.

Abstract 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.