Janeway, Katherine A

AbstractPatients with resectable Ewing sarcoma (ES) in select sites, such as the pelvis or chest wall, have a higher risk of positive microscopic margins following surgery. AEWS1031 was the first North American/Australasia ES cooperative group trial allowing standardized preoperative radiotherapy, intended to minimize the morbidity of combined modality local tumor control as well as improve the likelihood of clear surgical margins. In this study, we found that the use of low‐dose preoperative radiation to a smaller target volume resulted in a high rate of R0 resection. The robust pathologic response rate strengthens existing evidence illustrating the radiosensitivity of Ewing sarcoma.

PURPOSE The National Cancer Institute-Children's Oncology Group Pediatric Molecular Analysis for Therapy Choice trial assigned patients age 1-21 years with relapsed or refractory solid tumors, lymphomas, and histiocytic disorders to phase II treatment arms of molecularly targeted therapies on the basis of genetic alterations detected in their tumor. Patients with tumors that harbored prespecified genomic alterations in the cyclinD-CDK4/6-INK4a-Rb pathway with intact Rb expression were assigned and treated with the cdk4/6 inhibitor palbociclib. METHODS Patients received palbociclib orally once daily for 21 days of 28-day cycles until disease progression, intolerable toxicity, or up to 2 years. The primary end point was objective response rate; secondary end points included safety/tolerability and progression-free survival. RESULTS Twenty-three patients (median age, 15 years; range, 8-21) were enrolled; 20 received protocol therapy and were evaluable for toxicity and response. Of the evaluable patients, the most common diagnoses were osteosarcoma (n = 9) and rhabdomyosarcoma (n = 6). A single actionable gene amplification was found in 19 tumors ( CDK4 , n = 11, CDK6 , n = 2, CCND3 , n = 6), with one tumor harboring two amplifications ( CDK4 and CCND2 ). Hematologic toxicities were the most common treatment-related events. No objective responses were seen. Two patients with tumors harboring CDK4 amplifications (neuroblastoma and sarcoma) had best response of stable disease for six and three cycles. Six-month progression was 10% (95% CI, 1.7 to 27.2). CONCLUSION The CDK4/6 inhibitor palbociclib at 75 mg/m 2 orally daily was tolerable in this heavily pretreated cohort. No objective responses were observed in this histology-agnostic biomarker-selected population with treatment-refractory solid tumors, demonstrating that pathway alteration alone is insufficient in pediatric cancers to generate a response to palbociclib monotherapy.

PURPOSE Patients age 1-21 years with relapsed or refractory solid and CNS tumors were assigned to phase II studies of molecularly targeted therapies on the National Cancer Institute-Children's Oncology Group (NCI-COG) Pediatric Molecular Analysis for Therapy Choice (MATCH) trial. Patients whose tumors harbored predefined genetic alterations in the phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway and lacked mitogen-activated protein kinase pathway activating alterations were treated with the PI3K/mTOR inhibitor samotolisib. METHODS Patients received samotolisib twice daily in 28-day cycles until disease progression or unacceptable toxicity. A rolling 6 limited dose escalation was performed as, to our knowledge, this was the first pediatric study of samotolisib. The primary end point was the objective response rate; secondary end points included progression-free survival (PFS) and the recommended phase II dose and toxicity of samotolisib in children. RESULTS A total of 3.4% (41/1,206) of centrally tested patients were matched to this arm. Seventeen patients were treated. Among treated patients, the most common diagnoses included osteosarcoma (n = 6) and high-grade glioma (n = 5) harboring alterations in phosphatase and tensin homolog (n = 6), PIK3CA (n = 5), and tuberous sclerosis complex 2 (n = 3). No objective responses or prolonged stable disease were observed. Three-month PFS was 12% (95% CI, 2 to 31). Two patients experienced dose-limiting toxicities (mucositis and pneumonitis). Dose level 2 (115 mg/m 2 /dose twice daily) was determined to be the recommended phase II dose of samotolisib in children. CONCLUSION This nationwide study was successful at identifying patients and evaluating the efficacy of molecularly targeted therapy for rare molecular subgroups of patients in a histology-agnostic fashion. Unfortunately, there was no activity of samotolisib against tumors with PI3K/mTOR pathway alterations. Prospective trials such as the NCI-COG Pediatric MATCH are necessary to evaluate the efficacy of molecularly targeted therapies given their increasing use in clinical practice.

PURPOSE The National Cancer Institute-Children's Oncology Group (NCI-COG) Pediatric MATCH trial assigns patients age 1-21 years with refractory malignancies to phase II treatment arms of molecularly targeted therapies on the basis of genetic alterations detected in their tumor. Patients with activating alterations in the mitogen-activated protein kinase pathway were treated with ulixertinib, an extracellular signal-regulated kinase (ERK)1/2 inhibitor. METHODS As there were no previous pediatric data, ulixertinib was initially tested in a dose escalation cohort to establish the recommended phase II dose (RP2D) before proceeding to the phase II cohort. Ulixertinib was administered at 260 mg/m2/dose orally twice a day (dose level 1 [DL1], n = 15) or 350 mg/m2/dose orally twice a day (DL2, n = 5). The primary end point was objective response rate; secondary end points included safety/tolerability and progression-free survival (PFS). RESULTS Twenty patients (median 12 years; range, 5-20) were treated, all evaluable for response. CNS tumors comprised 55% (11/20) of diagnoses, with high-grade glioma and low-grade glioma most common (n = 5 each). All CNS tumors except one harbored BRAF fusions or V600E mutations. Rhabdomyosarcoma (n = 5) was the most frequent non-CNS diagnosis. DL1 was declared the RP2D in the dose escalation cohort after dose-limiting toxicities in Cycle 1 occurred in 1/6 patients at DL1 and 2/5 patients at DL2, including fatigue, anorexia, rash, nausea, vomiting, diarrhea, dehydration, hypoalbuminemia, and hypernatremia. No objective responses were observed. Six-month PFS was 37% (95% CI, 17 to 58). Three patients with BRAF-altered CNS tumors achieved stable disease >6 months. CONCLUSION Ulixertinib, a novel targeted agent with no previous pediatric data, was successfully evaluated in a national precision medicine basket trial. The pediatric RP2D of ulixertinib is 260 mg/m2/dose orally twice a day. Limited single-agent efficacy was observed in a biomarker-selected cohort of refractory pediatric tumors.

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 NCI-COG Pediatric MATCH trial assigns patients age 1-21 years with relapsed or refractory solid tumors, lymphomas, and histiocytic disorders to phase II studies of molecularly targeted therapies on the basis of detection of predefined genetic alterations. Patients with tumors harboring mutations or fusions driving activation of the mitogen-activated protein kinase (MAPK) pathway were treated with the MEK inhibitor selumetinib. METHODS Patients received selumetinib twice daily for 28-day cycles until disease progression or intolerable toxicity. The primary end point was objective response rate; secondary end points included progression-free survival and tolerability of selumetinib. RESULTS Twenty patients (median age: 14 years) were treated. All were evaluable for response and toxicities. The most frequent diagnoses were high-grade glioma (HGG; n = 7) and rhabdomyosarcoma (n = 7). Twenty-one actionable mutations were detected: hotspot mutations in KRAS (n = 8), NRAS (n = 3), and HRAS (n = 1), inactivating mutations in NF1 (n = 7), and BRAF V600E (n = 2). No objective responses were observed. Three patients had a best response of stable disease including two patients with HGG ( NF1 mutation, six cycles; KRAS mutation, 12 cycles). Six-month progression-free survival was 15% (95% CI, 4 to 34). Five patients (25%) experienced a grade 3 or higher adverse event that was possibly or probably attributable to study drug. CONCLUSION A national histology-agnostic molecular screening strategy was effective at identifying children and young adults eligible for treatment with selumetinib in the first Pediatric MATCH treatment arm to be completed. MEK inhibitors have demonstrated promising responses in some pediatric tumors (eg, low-grade glioma and plexiform neurofibroma). However, selumetinib in this cohort with treatment-refractory tumors harboring MAPK alterations demonstrated limited efficacy, indicating that pathway mutation status alone is insufficient to predict response to selumetinib monotherapy for pediatric cancers.

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.