Gorlick, Richard

Abstract Purpose: Mouse models demonstrate a role for RANK and its ligand, RANKL, in osteosarcoma. The primary objective of this single-arm, open-label phase 2 trial was to determine whether denosumab, a RANKL mAb, improved disease control in recurrent osteosarcoma relative to benchmarks derived from historic Children’s Oncology Group clinical trial data. Patients and Methods: Skeletally mature patients ages 11 to 49 years old with measurable disease were eligible for cohort 1, and those with complete surgical resection of all sites of disease were eligible for cohort 2. Patients received denosumab 120 mg subcutaneously every 4 weeks with calcium and vitamin D supplementation. The primary endpoints were RECIST response and remaining event-free for 4 months for cohort 1 and remaining event-free for 12 months for cohort 2. Toxicity, pharmacokinetics, and pharmacodynamic effects were additional endpoints. Results: Fifteen patients in cohort 1 and 38 in cohort 2 were eligible and evaluable for the primary endpoint. One of 15 cohort 1 patients remained event-free at 4 months. There were no objective responses. Ten of 38 cohort 2 patients were event-free at 12 months. The predefined efficacy criteria were not met in either cohort. The most common ≥ grade 3 adverse events were hypocalcemia and hypophosphatemia (8% and 11%, respectively). At steady state, mean serum denosumab trough concentrations were 23.7 to 31 μg/mL in cycles 2 to 7. Serum c-telopeptide and urine n-telopeptide decreased on treatment. Conclusions: Denosumab was well-tolerated with anticipated side effects and pharmacokinetic and pharmacodynamic parameters but had insufficient activity for further development in osteosarcoma.

PURPOSE Human epidermal growth factor receptor 2 (HER2), a transmembrane receptor with kinase activity involved in cell signaling through the RAS pathway, is expressed in osteosarcoma (OST). Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate with a HER2-targeting monoclonal antibody, trastuzumab, linked to a topoisomerase I inhibitor. We report results of a phase II study of T-DXd in adolescents and young adults with HER2-positive relapsed, unresectable OST (ClinicalTrials.gov identifier: NCT04616560 ). METHODS Patients age 12-39 years with relapsed, unresectable OST were eligible for centrally evaluated HER2 expression screening by immunohistochemistry. Patients with >10% of OST cells with cytoplasmic or membranous HER2 expression of any intensity were eligible to receive T-DXd at 5.4 mg/kg intravenously once every 3 weeks for up to 2 years. The study used a 9 + 15 Simon's optimal two-stage design with a primary end point of event-free survival at 24 weeks. RESULTS Fifty patients were screened for HER2, and 41 met the inclusion criteria of 10% of OST cells having membranous or cytoplasmic HER2 expression. Nine eligible patients, two younger than 18 years, were enrolled and received T-DXd. With a single patient having more than 24 weeks of stable disease (SD) of the nine planned in the first stage, this study did not meet criteria to progress to stage II. The estimated SD rate at 24 weeks is 11.1%. The median (range) number of cycles of therapy was 2 (2-12). Grade 3 and 4 possibly related adverse events occurred in three of nine patients and included nausea, vomiting, tumor hemorrhage, cytopenias (n = 3), wound infection, and hypertension. CONCLUSION T-DXd did not demonstrate sufficient activity to expand enrollment to the planned second stage in patients with OST. No new safety signals were observed.

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.

BackgroundCurative therapy for ES requires both chemotherapy and local control of primary tumor. There is no universally accepted standard approach to local control modalities. This survey was conducted to determine practice patterns and factors influencing the choice to offer various local control modalities to patients with ES of the spine and pelvis.MethodsThe survey consisted of four scenarios involving a 15‐year‐old girl who presented with Ewing sarcoma of thoracic vertebra, sacrum, iliac wing, and acetabulum with or without neurologic compromise. The questionnaire was sent to oncologists, orthopedic surgeons, and radiation oncologists, asking their recommendations for local control modality.ResultsAmong 94 respondents, radiotherapy was most frequently chosen for sacral tumors (68.1%) and T10 vertebral tumors (46.2%) whereas surgery was preferred for iliac wing pelvic tumors (45.7%) and acetabular tumors (43.6%). Orthopedic surgeons were significantly more likely to offer surgery than radiation oncologists (OR 3.07, 95%CI 1.37‐6.88, P = 0.007). Providers outside North America were more likely to offer combined surgery plus radiotherapy (OR 10.58, 95%CI 5.41‐20.70, P < 0.001).ConclusionConsiderable heterogeneity exists in local control modalities for Ewing sarcoma of the spine and pelvis. Specialty and location of practice may influence treatment recommendations.