IMMU-13. CUSTOMIZABLE MULTI-LAMELLAR RNA-NANOPARTICLES FOR PEDIATRIC GLIOMA. (1st June 2021)

• Record Type: Journal Article
• Authors: Mendez-Gomez, Hector; McGuiness, James; grippin, Adam; Weidert, Frances; Carrera-Justiz, Sheila; Mitchell, Duane; Sayour, Elias
• Is Part Of: Neuro-oncology. Volume 23(2021)Supplement 1
• Page Start: i29
• Page End: i30
• Publication Date: 2021-06-01
• Subjects: Brain Neoplasms -- Periodicals; Brain -- Tumors -- Periodicals; Brain -- Cancer -- Periodicals; Nervous system -- Cancer -- Periodicals; 616.99481
• DOI: 10.1093/neuonc/noab090.120
• Languages: English
• ISSNs: 1522-8517

Abstract

Abstract: Background: Since the preponderance of pediatric gliomas are mutationally 'bland, ' immune checkpoint inhibitors are unlikely to mediate therapeutic benefit. Alternately, immunologic response can be induced de novo against pediatric gliomas with mRNA cancer vaccines. Messenger RNA represents a paradigm shift in vaccinology (i.e. COVID-19) given its flexibility, commercialization, and propensity to confer rapid protection with only a single vaccine. Objective: We sought to develop a new mRNA platform with an optimized backbone for insertion of both personalized and/or "off the shelf' (i.e. H3K27M) transcripts for rapid induction of anti-tumor activity against pediatric gliomas. Approach: We synthesized an mRNA backbone with optimized 5' and 3' UTRs for delivery of gene transcripts pertinent to pediatric brain tumors using a lipid-nanoparticle (NP) delivery vehicle. This vaccine utilizes a novel engineering design that layers tumor derived mRNA into a lipid-nanoparticle (NP) "onion-like" or multi-lamellar package. Results: We demonstrate immunogenicity of RNA-NPs delivering either personalized glioma mRNA or H3K27M mRNA. RNA-NPs localize to myeloid cells in murine KR158b brain tumors and activate dendritic cells that supplant regulatory intratumoral myeloid populations inducing antigen-recall response with long-term survivor benefit. Our optimized mRNA backbone yielded significantly improved anti-tumor efficacy compared with commercial backbones. We have shown this approach can be refined for co-delivery of immunomodulatory RNAs (i.e. GM-CSF) and/or delivery of siRNAs targeting immunoregulatory axes (PD-L1) in murine brain tumors (GL261). We have since established safety of RNA-NPs in acute/chronic murine GLP toxicity studies without cross-reactivity to normal-brain, and launched a large-animal canine brain tumor trial which demonstrated RNA-NPs to be feasible, safe and immunologically active. Conclusion: RNA-NPs reprogram the brain tumor microenvironment while inducing a glioma-specific immune response. We have since received FDA-IND approval for first-in-human trials (IND#BB-19304) in pediatric patients with high-grade gliomas (PNOC020 study, NCT04573140).