Trametinib-based Treatment of Pediatric CNS Tumors: A Single Institutional Experience.

MEK inhibitors are an emerging therapy with increasing use in mitogen-activated protein kinase-driven central nervous system (CNS) tumors. There is limited data regarding efficacy and toxicity in pediatric patients. We report our clinical experience with trametinib-based therapy for the treatment of 14 consecutive pediatric patients with recurrent low-grade glioma (N=11) or high-grade CNS tumors (N=3) with MAP kinase pathway mutations. Patients received trametinib as monotherapy (N=9) or in combination (N=5) with another antineoplastic agent. Nine patients (64%) were progression free during treatment. Five patients showed a partial response, while 4 had stable disease. Two patients (14%) progressed on therapy. All partial responses were in patients with low-grade tumors. The remaining 3 patients were not evaluable due to toxicity limiting duration of therapy. Two of 3 patients with low-grade glioma with leptomeningeal dissemination showed radiographic treatment response. Five patients reported improved clinical symptoms while on trametinib. Adverse events on trametinib-based therapy included dermatologic, mouth sores, fever, gastrointestinal, infection, neutropenia, headache, and fatigue, and were more common in patients using combination therapy. Trametinib-based therapy demonstrated signals of efficacy in our single institutional cohort of pediatric patients with mitogen-activated protein kinase-driven CNS tumors. Our observations need to be confirmed in a clinical trial setting.

Pediatric versus adult high grade glioma: Immunotherapeutic and genomic considerations.

High grade gliomas are identified as malignant central nervous tumors that spread rapidly and have a universally poor prognosis. Historically high grade gliomas in the pediatric population have been treated similarly to adult high grade gliomas. For the first time, the most recent classification of central nervous system tumors by World Health Organization has divided adult from pediatric type diffuse high grade gliomas, underscoring the biologic differences between these tumors in different age groups. The objective of our review is to compare high grade gliomas in the adult versus pediatric patient populations, highlighting similarities and differences in epidemiology, etiology, pathogenesis and therapeutic approaches. High grade gliomas in adults versus children have varying clinical presentations, molecular biology background, and response to chemotherapy, as well as unique molecular targets. However, increasing evidence show that they both respond to recently developed immunotherapies. This review summarizes the distinctions and commonalities between the two in disease pathogenesis and response to therapeutic interventions with a focus on immunotherapy.

Clinical and Neuroimaging Features of Magnetic Resonance-Guided Stereotactic Laser Ablation for Newly Diagnosed and Recurrent Pediatric Brain Tumors: A Single Institutional Series.

OBJECTIVE: We describe our single-institutional experience with magnetic resonance-guided stereotactic laser ablation (SLA) for the treatment of newly diagnosed and recurrent pediatric brain tumors. METHODS: Eighteen consecutive ablation procedures were performed in 17 patients from March 2016-April 2020. Patient demographics, indications, procedures, neuroimaging features, and outcomes were reviewed retrospectively. RESULTS: Seventeen patients (mean age of 11.4 years, 11 boys, 6 girls) underwent SLA with a mean follow-up of 24 months (range: 3-45 months). Tumor histologies included pilocytic astrocytoma (n = 5), ganglioglioma (n = 3), low-grade glioma not otherwise specified (n = 4), glioblastoma (n = 2), meningioma (n = 1), medulloblastoma (n = 1), and metastatic malignant peripheral nerve sheath tumor (n = 1). SLA was first-line therapy in 10 patients. Mean procedure duration including anesthesia time was 328 minutes (range: 244-529 minutes), and mean postoperative length of stay was 1.5 days (range 1-5 days). The complication rate was 29%, which included 3 patients who experienced postoperative motor changes, which resolved within several weeks of surgery, 1 patient with self-limited intraoperative bradycardia and hypotension, and 1 patient who died postoperatively due to intracranial hemorrhage from a distant lesion. Twelve of 17 patients had a neuroimaging response after SLA (4 complete responses, 8 partial responses, 1 stable disease). Percentage of tumor shrinkage from baseline ranged from 33%-100% (mean 75%). Patients with low-grade glioma exhibited the best responses to SLA (range 3%-100% decrease; mean 90%; 36% complete response rate). CONCLUSIONS: SLA is a minimally invasive modality for the treatment of newly diagnosed and recurrent low-grade pediatric brain tumors. Low-grade glioma exhibited the best responses. Identification of ideal candidates for SLA, mitigation of perioperative complications, and demonstration of long-term outcomes need to be better defined in a clinical trial setting.

CAR-T Cell Therapy for Acute Lymphoblastic Leukemia: Transforming the Treatment of Relapsed and Refractory Disease.

PURPOSE OF REVIEW: Genetically engineered T cells expressing a chimeric antigen receptor (CAR-T) targeting specific antigens present on acute lymphoblastic leukemia (ALL) blasts have generated promising results in children and adults with relapsed and refractory disease. We review the current evidence for CAR-T cell therapy in ALL, associated toxicities, and efforts to improve durable response to therapy. RECENT FINDINGS: CD19-directed CAR-T cells have recently been approved by the FDA for use in children and young adults with ALL and in adults with diffuse large B cell lymphoma (DLBCL) in the relapsed/refractory setting. CD22-directed CAR-T cells have shown efficacy against leukemia as well in a recent clinical trial, representing the first alternative CAR target to approach comparable efficacy to CD19 CAR-T cells. Standardization of toxicity grading and management, strategies to combat significant relapse rates after CAR-T therapy, and applicability of CAR-T cells to treat central nervous system (CNS) disease remain challenges in the field and represent priorities for continued research. CAR-T cells are a feasible, effective, and rapidly evolving therapy for patients with relapsed and refractory B cell malignancies.