In vivo targeted delivery of nucleic acids to hematopoietic stem cells for treating primary immunodeficiencies

Summary In this Phase I SBIR, Optimeos will develop an off-the-shelf nanoparticle platform for in vivo stem cell gene therapy, which we will initially apply to treat ADA-SCID, a severe immune deficiency. We will deliver a DNA payload in nanoparticles targeting hematopoietic stem and progenitor cells (HSPCs) for gene replacement. We envision that this non-viral, redosable in vivo HSPC gene therapy will enable the expression of encapsulated DNA in target cells while improving safety by avoiding viral integration and potential off-target effects. This therapy has the potential to overcome several challenges posed by ex vivo gene and cell therapies: it could lower treatment costs, expand treatment availability beyond major academic centers, and reduce patient burden by obviating the need for chemotherapeutic pre-conditioning. With over 6 million people worldwide affected by more than 485 distinct inborn errors of immunity, our in vivo HSPC gene therapy platform has the potential to be transformative for many underserved patients. As an initial indication, ADA-SCID is a disease with established animal models and clinical pathways to reduce development risks. Our Coated Inverse NanoCarriers (CINCs) encapsulate nucleic acids in a polymer-lipid hybrid structure that minimizes inflammation and enhances targeted delivery by providing stable attachment of the targeting ligand, offering a clear advantage over traditional lipid nanoparticles (LNPs). The targeting capabilities of CINCs will enable us to reach HSPCs in bone marrow using a selective antibody as a targeting ligand while minimizing non-specific liver clearance. Across the two aims of this proposal, we will select our lead CINC formulations and demonstrate durable gene expression in HSPCs with episomally maintained DNA cargos in vitro and in vivo. Aim 1: Optimize CINC and targeting ligand formulations to achieve potent and specific delivery to HSPCs in vitro and in vivo. We will select the targeted CINC formulations that exhibit both high transfection efficiency and specificity in HSPCs, in vitro and in vivo. We expect that lead targeted CINCs will reduce liver uptake and enhance HSPC transfection compared to control CINCs. Aim 2: Determine durability and safety of gene replacement in vivo. Utilizing our lead targeted CINCs, we will deliver an episomally maintained DNA plasmid co-expressing GFP and human ADA genes to HSPCs, in vitro and in vivo, to assess durability and safety of gene replacement. We expect durable expression of plasmid DNA in HSPCs and daughter lineages. We expect to observe no concerning safety signals as a result of the immune-silent design of CINCs and the reduce liver clearance achieved through the course of these aims. In Phase II, we plan to demonstrate the efficacy of our targeted CINCs in a mouse model of adenosine deaminase-severe combined immunodeficiency (ADA-SCID).