Phase 1 study of NEDD8 activating enzyme inhibitor pevonedistat in combination with chemotherapy in pediatric patients with recurrent or refractory solid tumors (ADVL1615).

PURPOSE: The objective of this study was to determine the recommended Phase 2 dose (RP2D) of pevonedistat, a first in class inhibitor of NEDD8 activating enzyme, in combination with irinotecan (IRN) and temozolomide (TMZ) in children with cancer. METHODS: This Phase 1 study used a rolling 6 design to evaluate escalating doses of pevonedistat in combination with standard doses of IRN and TMZ in pediatric patients with recurrent/refractory solid or CNS tumors. During cycle 1, pevonedistat was administered intravenously on days 1, 8, 10, and 12, with IRN (IV, 50 mg/m2) and TMZ (orally, 100 mg/m2), on days 8-12 of a 28-day cycle. In subsequent cycles, pevonedistat was administered on days 1, 3, and 5, with IRN/TMZ on days 1-5 of a 21-day cycle. RESULTS: Thirty patients enrolled; all were eligible and evaluable for toxicity. Six patients each enrolled on pevonedistat dose levels (DL) 1 (15 mg/m2), 2 (20 mg/m2), 3 (25 mg/m2) and 4 (35 mg/m2) as well as an expanded pharmacokinetic (PK) cohort at DL4. The maximum tolerated dose (MTD) was not exceeded. 2/12 (17 %) patients treated at the RP2D (35 mg/m2) experienced a cycle 1 dose limiting toxicity (DLT). IRN is unlikely to affect the pharmacokinetics of pevonedistat. Two patients had a partial response and 6 patients had prolonged stable disease (> 6 cycles). CONCLUSIONS: Pevonedistat in combination with IRN/TMZ is well tolerated in children with solid or CNS tumors. The RP2D of pevonedistat is 35 mg/m2 on days 1, 3, 5 in combination with IRN/TMZ.

Roadmap for the next generation of Children's Oncology Group rhabdomyosarcoma trials.

Clinical trials conducted by the Intergroup Rhabdomyosarcoma (RMS) Study Group and the Children's Oncology Group have been pivotal to establishing current standards for diagnosis and therapy for RMS. Recent advancements in understanding the biology and clinical behavior of RMS have led to more nuanced approaches to diagnosis, risk stratification, and treatment. The complexities introduced by these advancements, coupled with the rarity of RMS, pose challenges to conducting large-scale phase 3 clinical trials to evaluate new treatment strategies for RMS. Given these challenges, systematic planning of future clinical trials in RMS is paramount to address pertinent questions regarding the therapeutic efficacy of drugs, biomarkers of response, treatment-related toxicity, and patient quality of life. Herein, the authors outline the proposed strategic approach of the Children's Oncology Group Soft Tissue Sarcoma Committee to the next generation of RMS clinical trials, focusing on five themes: improved novel agent identification and preclinical to clinical translation, more efficient trial development and implementation, expanded opportunities for knowledge generation during trials, therapeutic toxicity reduction and quality of life, and patient engagement.

Paediatric strategy forum for medicinal product development of PI3-K, mTOR, AKT and GSK3ß inhibitors in children and adolescents with cancer.

Phosphatidylinositol 3-kinase (PI3-K) signalling pathway is a crucial path in cancer for cell survival and thus represents an intriguing target for new paediatric anti-cancer drugs. However, the unique clinical toxicities of targeting this pathway (resulting in hyperglycaemia) difficulties combining with chemotherapy, rarity of mutations in childhood tumours and concomitant mutations have resulted in major barriers to clinical translation of these inhibitors in treating both adults and children. Mutations in PIK3CA predict response to PI3-K inhibitors in adult cancers. The same mutations occur in children as in adults, but they are significantly less frequent in paediatrics. In children, high-grade gliomas, especially diffuse midline gliomas (DMG), have the highest incidence of PIK3CA mutations. New mutation-specific PI3-K inhibitors reduce toxicity from on-target PI3-Kα wild-type activity. The mTOR inhibitor everolimus is approved for subependymal giant cell astrocytomas. In paediatric cancers, mTOR inhibitors have been predominantly evaluated by academia, without an overall strategy, in empiric, mutation-agnostic clinical trials with very low response rates to monotherapy. Therefore, future trials of single agent or combination strategies of mTOR inhibitors in childhood cancer should be supported by very strong biological rationale and preclinical data. Further preclinical evaluation of glycogen synthase kinase-3 beta inhibitors is required. Similarly, even where there is an AKT mutation (∼0.1 %), the role of AKT inhibitors in paediatric cancers remains unclear. Patient advocates strongly urged analysing and conserving data from every child participating in a clinical trial. A priority is to evaluate mutation-specific, central nervous system-penetrant PI3-K inhibitors in children with DMG in a rational biological combination. The choice of combination, should be based on the genomic landscape e.g. PTEN loss and resistance mechanisms supported by preclinical data. However, in view of the very rare populations involved, innovative regulatory approaches are needed to generate data for an indication.

Efficacy of the Allosteric MEK Inhibitor Trametinib in Relapsed and Refractory Juvenile Myelomonocytic Leukemia: a Report from the Children's Oncology Group.

Juvenile myelomonocytic leukemia (JMML) is a hematologic malignancy of young children caused by mutations that increase Ras signaling output. Hematopoietic stem cell transplantation (HSCT) is a potentially curative treatment, but patients with relapsed or refractory (advanced) disease have dismal outcomes. This phase II trial evaluated the safety and efficacy of trametinib, an oral MEK1/2 inhibitor, in patients with advanced JMML. Ten infants and children were enrolled, and the objective response rate was 50%. Four patients with refractory disease proceeded to HSCT after receiving trametinib. Three additional patients completed all 12 cycles permitted on study and continue to receive off-protocol trametinib without HSCT. The remaining three patients had progressive disease with two demonstrating molecular evolution by the end of cycle 2. Transcriptomic and proteomic analyses provided novel insights into the mechanisms of response and resistance to trametinib in JMML. ClinicalTrials.gov Identifier: NCT03190915. Significance: Trametinib was safe and effective in young children with relapsed or refractory JMML, a lethal disease with poor survival rates. Seven of 10 patients completed the maximum 12 cycles of therapy or used trametinib as a bridge to HSCT and are alive with a median follow-up of 24 months.

Phase II Study of Ulixertinib in Children and Young Adults With Tumors Harboring Activating Mitogen-Activated Protein Kinase Pathway Alterations: APEC1621J of the National Cancer Institute-Children's Oncology Group Pediatric MATCH Trial.

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.

Phase II study of vemurafenib in children and young adults with tumors harboring BRAF V600 mutations: NCI-COG pediatric MATCH trial (APEC1621) Arm G.

BACKGROUND: This is a phase II subprotocol of the NCI-COG Pediatric MATCH study evaluating vemurafenib, a selective oral inhibitor of BRAF V600 mutated kinase, in patients with relapsed or refractory solid tumors harboring BRAF V600 mutations. METHODS: Patients received vemurafenib at 550 mg/m2 (maximum 960 mg/dose) orally twice daily for 28-day cycles until progression or intolerable toxicity. The primary aim was to determine the objective response rate and secondary objectives included estimating progression-free survival and assessing the tolerability of vemurafenib. RESULTS: Twenty-two patients matched to the subprotocol and 4 patients (18%) enrolled. Primary reasons for non-enrollment were ineligibility due to exclusions of low-grade glioma (n = 7) and prior BRAF inhibitor therapy (n = 7). Enrolled diagnoses were one each of histiocytosis, ameloblastoma, Ewing sarcoma, and high-grade glioma, all with BRAF V600E mutations. Treatment was overall tolerable with mostly expected grade 1/2 adverse events (AE). Grade 3 or 4 AE on treatment were acute kidney injury, hyperglycemia, and maculopapular rash. One patient came off therapy due to AE. One patient (glioma) had an objective partial response and remained on protocol therapy for 15 cycles. CONCLUSION: There was a low accrual rate on this MATCH subprotocol, with only 18% of those who matched with BRAFV600 mutations enrolling, resulting in early termination, and limiting study results (ClinicalTrials.gov Identifier: NCT03220035).

Olaparib for childhood tumors harboring defects in DNA damage repair genes: arm H of the NCI-COG Pediatric MATCH trial.

BACKGROUND: The National Cancer Institute-Children's Oncology Group Pediatric Molecular Analysis for Therapy Choice (MATCH) precision oncology platform trial enrolled children aged 1-21 years with treatment-refractory solid tumors and predefined actionable genetic alterations. Patients with tumors harboring alterations in DNA damage repair (DDR) genes were assigned to receive olaparib. METHODS: Tumor and blood samples were submitted for centralized molecular testing. Tumor and germline sequencing were conducted in parallel. Olaparib was given twice daily for 28-day cycles starting at a dose 30% lower than the adult recommended phase 2 dose (RP2D). The primary endpoint was the objective response. RESULTS: Eighteen patients matched (1.5% of those screened) based on the presence of a deleterious gene alteration in BRCA1/2, RAD51C/D, or ATM detected by tumor sequencing without germline subtraction or analysis of loss of heterozygosity (LOH). Eleven (61%) harbored a germline mutation, with only one exhibiting LOH. Six patients enrolled and received the olaparib starting dose of 135 mg/m2/dose. Two participants were fully evaluable; 4 were inevaluable because <85% of the prescribed dose was administered during cycle 1. There were no dose-limiting toxicities or responses. Minimal hematologic toxicity was observed. CONCLUSION: Most DDR gene alterations detected in Pediatric MATCH were germline, monoallelic, and unlikely to confer homologous recombination deficiency predicting sensitivity to olaparib monotherapy. The study closed due to poor accrual. CLINICALTRIALS.GOV IDENTIFIER: NCT03233204. IRB approved: initial July 24, 2017.

Sex differences in osteosarcoma survival across the age spectrum: A National Cancer Database analysis (2004-2016).

BACKGROUND: Osteosarcoma displays a bimodal peak in incidence in adolescence and later adulthood. Males are more frequently diagnosed with osteosarcoma in both periods. Males have worse survival than females, which is generally poor at 30-70% 5-years post diagnosis, depending on age, but treatment received is often unaccounted for in survival analyses. METHODS: Therefore, we estimated sex differences in survival for children and adults stratifying by treatment received and other disease characteristics using the National Cancer Database (2004-2016, n=9017). We estimated sex differences in long-term survival using Kaplan Meier survival curves and Log-Rank p-values. We also estimated hazard ratios (HR) and 95% confidence intervals (CIs) as the measure of association between sex and death using Cox regression. RESULTS: In all age groups, cases were predominantly male (52-58%). In Kaplan-Meier analyses, males had worse overall survival than females for 0-19, 20-39, and ≥60-year-olds (Log-Rank p<0.05). Females had higher 5- and 10-year survival percentages in all age groups. In adjusted Cox models, males had a higher risk of death among 0-19-year-olds (HRoverall: 1.24, 95% CI: 1.06-1.44; HRnon-metastatic disease: 1.35, 95% CI: 1.12, 1.63, HRlower limb tumors: 1.31, 95% CI: 1.09-1.59). Among 20-39-year-olds, males had an increased risk of death when receiving surgery only (HR: 4.67, 95% CI: 1.44, 15.09). Among those ≥60-year-olds, males had a suggestive increased risk of death overall (HR: 1.17, 95% CI: 0.99-1.39) and a higher risk of death based on some tumor locations, (HRupper limb: 2.52, 95% CI: 1.24, 5.11; HRmidline: 1.36, 95% CI: 1.02, 1.82). CONCLUSIONS: Our findings suggest that the worse survival among young males compared to females with osteosarcoma persisted after accounting for many major disease characteristics, including treatment received. Collectively, our work points toward other unexplored mechanisms beyond treatment, potentially biologic or otherwise, which may be driving the observed sex differences in long-term survival.

A phase 1/2 study of pepinemab in children, adolescents, or young adults with recurrent or refractory solid tumors: A children's oncology group consortium report (ADVL1614).

PURPOSE: Pepinemab, a humanized IgG4 monoclonal antibody, targets the SEMA4D (CD100) antigen to inhibit binding to its high-affinity receptors (plexin B1/PLXNB1, plexin B2/PLXNB2) and low-affinity receptor (CD72). SEMA4D blockade leads to increased cytotoxic T-cell infiltration, delayed tumor growth, and durable tumor rejection in murine tumor models. Pepinemab was well tolerated and improved T cell infiltration in clinical studies in adults with refractory tumors. SEMA4D was identified as a strong candidate proto-oncogene in a model of osteosarcoma. Based on these preclinical and clinical data, we conducted a phase 1/2 study to determine the recommended phase 2 dose (RP2D), pharmacokinetics, pharmacodynamics, and immunogenicity, of pepinemab in pediatric patients with recurrent/refractory solid tumors, and activity in osteosarcoma. EXPERIMENTAL DESIGN: Pepinemab was administered intravenously on Days 1 and 15 of a 28-day cycle at 20 mg/kg, the adult RP2D. Part A (phase 1) used a Rolling 6 design; Part B (phase 2) used a Simon 2-stage design in patients with osteosarcoma. Pharmacokinetics and target saturation were evaluated in peripheral blood. RESULTS: Pepinemab (20 mg/kg) was well tolerated and no dose-limiting toxicities were observed during Part A. There were no objective responses. Two patients with osteosarcoma achieved disease control and prolonged stable disease. Pepinemab pharmacokinetics were similar to adults. CONCLUSIONS: Pepinemab (20 mg/kg) is safe, well tolerated and resulted in adequate and sustained target saturation in pediatric patients. Encouraging disease control in two patients with osteosarcoma warrants further investigation with novel combination strategies to modulate the tumor microenvironment and antitumor immune response. CLINICAL TRIAL REGISTRY: This trial is registered as NCT03320330 at Clinicaltrials.gov. DISCLAIMER: The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

The Feasibility and Acceptability of a Data Capture Methodology in Pediatric Cancer Patients Treated with Targeted Agents and Immunotherapies.

As childhood cancer treatments have improved to include new and innovative agents, the need for more advanced monitoring of their long-term effects and related research has increased. This has resulted in a need for evidence-based research methodologies for the longitudinal care of childhood cancer patients treated with targeted agents and immunotherapies. The rationale for this pilot study was to determine the feasibility and acceptability of a data capture methodology for pediatric, adolescent, and young adult cancer patients treated with targeted agents and immunotherapy as there is little research to inform this delivery of care. Data were collected from thirty-two patients and two providers for descriptive statistics and thematic analyses. Feasibility was characterized by expected participant attrition. Key drivers of acceptability were (1) providers' language and clarity of communication and (2) convenient participation requirements. Long-term follow-up research practices developed with input from key stakeholders, including patients, caregivers, and providers, can lead to acceptable and feasible research protocols that optimize successful participant recruitment. These evidence-based research practices can result in high participant satisfaction and can be implemented as program development initiatives across centers caring for childhood cancer survivors.

A phase 1 trial utilizing a pharmacokinetic endpoint to determine the optimal dose of ramucirumab in children and adolescents with relapsed or refractory solid tumors, including central nervous system tumors.

BACKGROUND: Ramucirumab is a monoclonal antibody that binds the extracellular domain of vascular endothelial growth factor receptor (VEGFR-2) and prevents binding of VEGF ligands. Based on population pharmacokinetic (PK) analysis and correlation with efficacy in adults, a target steady state trough concentration (Css,min ) ≥ 50 µg/mL was established. PROCEDURES: This phase 1 trial (ADVL1416) used a rolling six design and a PK primary endpoint to define the recommended phase 2 dose (RP2D) of ramucirumab in children with recurrent/refractory solid tumors. Two dose levels (DL) were planned (DL1: 8 mg/kg, DL2: 12 mg/kg administered intravenously [IV] every 2 weeks). Toxicity during the initial 6 weeks was used to assess maximum tolerated dose (MTD). Cycle 1 Day 42 trough (Cmin ) ≥ 50 µg/mL was the target concentration for the PK endpoint. At the RP2D, cohorts for PK expansion and children with central nervous tumors were planned. RESULTS: Twenty-nine patients were enrolled; 28 were eligible; median age [range] = 13.5 [1-21] years; 22 were evaluable for the PK endpoint. Dose-limiting proteinuria occurred at both DLs; however, the MTD was not exceeded. At DL2 (12 mg/kg), the median Day 42 Cmin (n = 16) was 87.8 µg/mL; 15 of 16 patients achieved a Cmin  ≥ 50 µg/mL. CONCLUSION: Ramucirumab was well tolerated in children and adolescents with solid tumors. The RP2D for ramucirumab was 12 mg/kg IV every 2 weeks. This trial demonstrates the feasibility of incorporating a primary PK endpoint to determine dose escalation and the RP2D in children. Studies of ramucirumab in children with selected solid tumors are ongoing.