Publications by authors named "John A Ligon"

Successful cancer immunotherapy requires novel approaches that overcome intratumoral immunosuppression and peripheral tolerance. In a recent manuscript describing intravenously administered mRNA-loaded lipid particle aggregates (RNA-LPAs), we demonstrate the ability to reprogram both the tumor microenvironment and periphery enabling cancer-specific immunity simultaneously generated to compete against immunologically 'cold' malignancies like glioblastoma.

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Pediatric Hispanic and Black patients with newly diagnosed B-acute lymphoblastic leukemia (B-ALL) experience worse overall survival (OS). We hypothesized that differential outcomes by race and ethnicity following relapse may contribute to disparities. We examined 2,053 patients with ALL enrolled on frontline Children's Oncology Group trials from 1996-2014 who relapsed.

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The success of cancer immunotherapies is predicated on the targeting of highly expressed neoepitopes, which preferentially favours malignancies with high mutational burden. Here we show that early responses by type-I interferons mediate the success of immune checkpoint inhibitors as well as epitope spreading in poorly immunogenic tumours and that these interferon responses can be enhanced via systemic administration of lipid particles loaded with RNA coding for tumour-unspecific antigens. In mice, the immune responses of tumours sensitive to checkpoint inhibitors were transferable to resistant tumours and resulted in heightened immunity with antigenic spreading that protected the animals from tumour rechallenge.

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Tumor-associated macrophages (TAMs) are abundant in the tumor microenvironment (TME) and dampen the immune response, negatively affecting patient survival. Therefore, targeting TAMs could address the limitations of current cancer treatments. However, drug development in this area remains limited.

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Ewing sarcoma (EwS) is a rare and aggressive malignancy, which frequently affects children. One of the few recurrent genomic variants in EwS is genomic copy number deletion of CDKN2A; however, the clinical consequences of dysregulation of CDKN2A in EwS are unclear. In this study, we revisit CDKN2A to investigate its role as a potential prognostic biomarker in EwS using data from EwS pre-clinical models as well as clinical samples from patients with EwS.

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Chimeric antigen receptor (CAR) T-cell therapy is a potentially life-saving treatment for children with relapsed/refractory B-cell hematologic malignancies, and remains an important investigational therapy for other childhood cancers. Yet, access to this class of therapies remains suboptimal through both commercial use and clinical trials, especially in children, adolescents, and young adults. Using a series of case-based discussions, we outline guidance on real-world medical decision-making, and offer potential solutions to enhancing access to CAR T-cell therapy as a treatment modality.

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Patients who receive allogeneic hematopoietic stem cell transplantation (alloHSCT) are at risk for developing persistent thrombocytopenia. Here, we describe treatment with avatrombopag, a thrombopoietin receptor agonist, in a pediatric patient with chronic, severe, transfusion-dependent thrombocytopenia (<10 × 10/µL) post-alloHSCT that was persistent despite treatment with romiplostim, another thrombopoietin receptor agonist. Following the granting of a compassionate use investigational new drug authorization, avatrombopag treatment was initiated, and the patient's platelet count increased.

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The use of immunotherapies for the treatment of cancer in children, adolescents, and young adults has become common. As the use of immunotherapy has expanded, including in earlier lines of therapy, it has become evident that several aspects of how these immunotherapies impact longer-term outcomes among survivors are understudied. Traditional cancer therapies like alkylating and platin agents carry the greatest risk of infertility, but little is known about the impact of novel immunotherapies on fertility.

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Background: Lagenidium deciduum is an oomycete that can cause infections in mammals that present similarly to pythiosis and mucormycosis. Most of the existing case reports have occurred in canines and have been fatal. In animals, medical therapy has not been successful, so surgical excision is the mainstay of treatment.

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Article Synopsis
  • Cancer immunotherapy faces challenges due to poor antigen recognition and an unfriendly tumor microenvironment (TME).
  • Researchers developed "onion-like" multi-lamellar RNA lipid particle aggregates (LPAs) that enhance the delivery and effectiveness of tumor mRNA antigens by activating specific immune responses in the body.
  • In studies with dogs and humans, RNA-LPAs showed promising results, improving survival rates and triggering strong immune reactions against tumors, suggesting they could be a breakthrough method for cancer treatment.
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Article Synopsis
  • The study investigates the use of mediports for administering CAR T cell therapy in patients with B-cell malignancies, aiming to establish standardized practices in this area due to previous concerns about effectiveness and safety.
  • Data was collected from 34 medical centers, analyzing 504 CAR T cell infusions, making it one of the largest reports on this topic since CAR T cell commercialization began in 2017.
  • Results showed that 85% of centers accepted mediports as standard practice, with no incidents of CAR T cell infiltration reported among the 184 patients infused via mediports, supporting their safe use in clinical settings.
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Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of B cell malignancies, with multiple CAR T cell products approved for numerous indications by regulatory agencies worldwide. However, significant work remains to be done to enhance these treatments. In March 2023, a group of experts in CAR T cell therapy assembled at the National Institutes of Health in Bethesda, Maryland at the Insights in Pediatric CAR T Cell Immunotherapy: Recent Advances and Future Directions (INSPIRED) Symposium to identify key areas for research for the coming years.

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Messenger RNA (mRNA) has emerged as a remarkable tool for COVID-19 prevention but its use for induction of therapeutic cancer immunotherapy remains limited by poor antigenicity and a regulatory tumor microenvironment (TME). Herein, we develop a facile approach for substantially enhancing immunogenicity of tumor-derived mRNA in lipid-particle (LP) delivery systems. By using mRNA as a molecular bridge with ultrapure liposomes and foregoing helper lipids, we promote the formation of 'onion-like' multi-lamellar RNA-LP aggregates (LPA).

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Background: Oncofertility is a developing field of increasing importance, particularly in pediatric oncology, where most patients are likely to survive long-term and have not yet had the opportunity to have children.

Aims: We performed a quality improvement initiative to increase our rates of fertility preservation counseling and referral through the implementation of a pediatric oncofertility team, and we report outcomes 7 years following implementation of our initiative.

Methods And Results: We compare our baseline oncofertility survey to 44 post-intervention survey respondents and electronic medical record documentation for 149 patients treated in 2019.

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Purpose: Succinate dehydrogenase (dSDH)-deficient tumors, including pheochromocytoma/paraganglioma, hereditary leiomyomatosis and renal cell cancer-associated renal cell carcinoma (HLRCC-RCC), and gastrointestinal stromal tumors (GIST) without KIT or platelet-derived growth factor receptor alpha mutations are often resistant to cytotoxic chemotherapy, radiotherapy, and many targeted therapies. We evaluated guadecitabine, a dinucleotide containing the DNA methyltransferase inhibitor decitabine, in these patient populations.

Patients And Methods: Phase II study of guadecitabine (subcutaneously, 45 mg/m2/day for 5 consecutive days, planned 28-day cycle) to assess clinical activity (according to RECISTv.

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Background Aims: The field of cell and gene therapy in oncology has moved rapidly since 2017 when the first cell and gene therapies, Kymriah followed by Yescarta, were approved by the Food and Drug Administration in the United States, followed by multiple other countries. Since those approvals, several new products have gone on to receive approval for additional indications. Meanwhile, efforts have been made to target different cancers, improve the logistics of delivery and reduce the cost associated with novel cell and gene therapies.

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Cancer outcomes with chemotherapy are inferior in patients of minority racial/ethnic groups and those with obesity. Chimeric antigen receptor (CAR) T-cell therapy has transformed outcomes for relapsed/refractory hematologic malignancies, but whether its benefits extend commensurately to racial/ethnic minorities and patients with obesity is poorly understood. With a primary focus on patients with B-cell acute lymphoblastic leukemia (B-ALL), we retrospectively evaluated the impact of demographics and obesity on CAR T-cell therapy outcomes in adult and pediatric patients with hematologic malignancies treated with CAR T-cell therapy across 5 phase 1 clinical trials at the National Cancer Institute from 2012 to 2021.

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This letter to the editor considers outcomes for underrepresented populations across early phase pediatric oncology clinical trials, considering barriers to equitable representation of minorities in clinical trials.

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Chimeric antigen receptor (CAR) T-cells serve to overcome chemotherapeutic resistance and have been proven to be highly effective in B-cell hematologic malignancies. Although initial use has been in patients with multiply relapsed/refractory disease, as CAR T-cells are used earlier in the treatment paradigm, it will be important to explore implications of this novel therapy on cancer late-effects. We sought to assess the current framework for considerations of fertility surrounding CAR T-cell use and identify opportunities for education and future research.

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Remission durability following single-antigen targeted chimeric antigen receptor (CAR) T-cells is limited by antigen modulation, which may be overcome with combinatorial targeting. Building upon our experiences targeting CD19 and CD22 in B-cell acute lymphoblastic leukemia (B-ALL), we report on our phase 1 dose-escalation study of a novel murine stem cell virus (MSCV)-CD19/CD22-4-1BB bivalent CAR T-cell (CD19.22.

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Advances from novel adoptive cellular therapies have yet to be fully realized for the treatment of children and young adults with solid tumors. This review discusses the strategies and preliminary results, including T-cell, NK-cell and myeloid cell-based therapies. While each of these approaches have shown some early promise, there remain challenges.

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Current guidelines recommend sampling each central-access lumen during the initial evaluation of febrile pediatric oncology patients. We investigated this recommendation's validity at centers implementing a diagnostic stewardship program to reduce blood cultures in critically ill children. Among 146 oncology patients admitted to the intensive care unit, there were 34 eligible blood culture-sets.

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Chimeric antigen receptor (CAR) T cells effectively eradicate medullary B-cell acute lymphoblastic leukemia (B-ALL) and can traffic to and clear central nervous system (CNS) involvement. CAR T-cell activity in non-CNS extramedullary disease (EMD) has not been well characterized. We systematically evaluated CAR T-cell kinetics, associated toxicities, and efficacy in B-ALL non-CNS EMD.

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Article Synopsis
  • * Our findings reveal significant variations in tumor-infiltrating lymphocytes and T cell receptor (TCR) counts that correlate with survival rates, particularly in osteosarcoma patients.
  • * We identified key immunotherapeutic targets for cancer treatments and validated multiple potential targets, including PRAME, contributing to a framework for immune-targeting strategies in pediatric extracranial solid tumors.
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