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.

A phase I trial of metformin in combination with vincristine, irinotecan, and temozolomide in children with relapsed or refractory solid and central nervous system tumors: A report from the national pediatric cancer foundation.

BACKGROUND: Patients with relapsed and refractory solid and central nervous system (CNS) tumors have poor outcomes and need novel therapeutic options. Vincristine, irinotecan, and temozolomide (VIT) is a common chemotherapy regimen in relapsed pediatric tumors with an established toxicity profile. Metformin shows preclinical anti-cancer activity through multiple pathways. METHODS: The objective of this Phase I trial was to establish the maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) of metformin in combination with VIT in children with relapsed and refractory solid and CNS tumors. A 3 + 3 design was used to test the addition of metformin at five dose levels (666, 999, 1333, 1666, and 2000 mg/m2 /day). Therapy toxicity, pharmacokinetics, and radiologic response to treatment were evaluated. RESULTS: Twenty-six patients (median age 13 years, range 2-18 years) were enrolled with 22 evaluable for toxicity. The most common diagnoses were Ewing sarcoma (n = 8), rhabdomyosarcoma (n = 3) and atypical teratoid/rhabdoid tumor (n = 3). The MTD was exceeded at Dose Level 5 due to two dose-limiting toxicities; both were Grade 3 diarrhea requiring prolonged hospitalization and intravenous fluids. The MTD was not determined due to study closure with less than six patients enrolled at Dose Level 4. Frequently observed toxicities were gastrointestinal (most notably diarrhea) and hematologic. Amongst 16 patients evaluable for best overall response, there was one complete response (Ewing sarcoma), three partial responses (Ewing sarcoma, glioblastoma multiforme, and alveolar rhabdomyosarcoma), and five patients with stable disease. CONCLUSIONS: The MTD of VIT with metformin was not determined due to premature study closure. We recommend an RP2D of Dose Level 4, 1666 mg/m2 /day. Radiographic responses were seen in multiple tumor types. Further evaluation for efficacy could be investigated in a Phase II trial.

A strategy to reduce cumulative anthracycline exposure in low-risk pediatric acute myeloid leukemia while maintaining favorable outcomes.

BACKGROUND: Advances in risk stratification have improved the 3-year disease-free survival (DFS) and overall survival (OS) of low-risk pediatric acute myeloid leukemia (LR-AML) to approximately 70 % and 85 % respectively. LR-AML is defined by favorable cytogenetic/molecular features and/or optimal early response to therapy. However, cumulative anthracycline exposure in contemporary Children's Oncology Group (COG) regimens approach a doxorubicin equivalent exposure of 540 mg/m2; with rates of non-infection related left ventricular systolic dysfunction (LVSD) approaching 15 %. This is a major cause of toxicity in these patients and precludes the further use of anthracyclines in the relapsed setting; therefore, strategies that reduce cardiotoxicity while maintaining excellent outcomes are needed. PATIENTS AND METHODS: Twenty-seven pediatric patients with LR-AML were treated with an anthracycline-reduced approach (Aflac-AML regimen) between 2011 and 2016. Patients received four courses of therapy including three high-dose cytarabine containing courses and a cumulative doxorubicin equivalent exposure of 390 mg/m2, a 28 % reduction in anthracycline dosing compared to current COG regimens. RESULTS: The 3-year DFS and OS was 70.0 % and 85.5 % respectively, from end of Induction I (first chemotherapy cycle) with a median follow-up of 3.2 years. These survival outcomes are comparable to current LR-AML regimens. Only two patients developed non-infection related LVSD during therapy and more importantly, none developed LVSD after completion of therapy. CONCLUSION: These findings suggest that LR-AML outcomes can be maintained using a reduced anthracycline chemotherapy regimen, resulting in lower cardiac toxicity. This new chemotherapy backbone is now being tested prospectively (NCT04326439) to further validate its use in pediatric LR-AML.

Gemcitabine/nab-paclitaxel for pediatric relapsed/refractory sarcomas.

BACKGROUND: Pediatric patients with relapsed/refractory sarcomas have poor outcomes and need novel therapies that provide disease control while maintaining an acceptable quality of life. The activity and toxicity of gemcitabine and nab-paclitaxel in combination has not been reported in pediatrics. PROCEDURE: We reviewed the records of fifteen relapsed/refractory patients and one treatment-naïve patient who received gemcitabine/nab-paclitaxel at our institution. RESULTS: Sixteen patients (median age 13.5 years, range 3-19 years) received 53 cycles of gemcitabine/nab-paclitaxel. Twenty-nine cycles (55%) resulted in ≥Grade 3 toxicity, with nonhematologic Grade ≥3 toxicities occurring in only eight of 53 cycles (15%). Patients received red blood cell and platelet transfusions in 23% and 4% of cycles, respectively. Grade ≥3 infectious toxicities occurred in 4% of cycles. Of 14 patients with measurable disease, there were no complete responses (CR), one partial response (PR; 7%), and six patients (43%) with stable disease (SD; median SD: 4.5 months, range: 2-19 months). In total, 31% of the patients derived clinical benefit (CR + PR + SD ≥ 4 months). Median time to progression was 72 days with a 4-month progression-free survival of 31% ± 12% and 1-year overall survival of 19% ± 10%. With a median follow-up for all 16 patients of 21 months from the first treatment with gemcitabine/nab-paclitaxel, one (6%) remains alive with disease. CONCLUSIONS: Gemcitabine/nab-paclitaxel is a relatively safe regimen with mainly hematologic toxicities. It offers a well-tolerated, palliative option providing clinical benefit in a subset of patients. A phase I trial of this combination is underway.

Hemophagocytic Lymphohistiocytosis Secondary to T Cell/Histiocyte-rich Large B Cell Lymphoma in an Adolescent Male.

Hemophagocytic Lymphohistiocytosis (HLH) is a hyperinflammatory disorder that may be encountered as a primary or secondary phenomenon. HLH secondary to lymphoma has been described, more frequently in adults than in children. T-cell/Histiocyte-rich B-cell lymphoma (THRLBCL) is a large B-cell lymphoma that resides in a microenvironment of robust host immune response and has previously been associated with HLH in adults. Here, we describe the first case of HLH secondary to THRLBCL in an adolescent patient.

Concurrent myeloid sarcoma, atypical teratoid/rhabdoid tumor, and hypereosinophilia in an infant with a germline SMARCB1 mutation.

We report a 1-year-old female child presenting with hypereosinophilia who was found to have concurrent myeloid sarcoma and a central nervous system (CNS) atypical teratoid/rhabdoid tumor (AT/RT). She was later found to have a germline mutation in SMARCB1. Concurrent hematologic malignancy and CNS AT/RT have not previously been described in the context of a SMARCB1 loss-of-function germline mutation.