In vivo delivery of Ab-directed CRISPR ribonucleoproteins for anal cancer immunotherapy

PROJECT SUMMARY: This year in the US, 9,760 people are expected to be diagnosed with anal cancer. The 5-year survival rate for metastatic anal cancer is only ~30% with standard of care chemotherapy. No regimens have been FDA- approved after chemotherapy has failed and only limited benefit has been shown with single agent immune checkpoint blockade (ICB). New treatment options are urgently needed to improve patient outcomes. The goal of this Direct to Phase II project is to develop TAGE-201, an intratumorally administered Antibody (Ab)- directed CRISPR gene editor to knockout ADAR in TME immune cells for use in combination with ICB. This new biologic is based on Spotlight Therapeutics’ proprietary Targeted Active Gene Editor (TAGE) platform. TAGE is a non-viral, non-nanoparticle delivery modality, comprised of an engineered CRISPR-Cas9 ribonucleoprotien (RNP) fused to an Ab, enabling cell-targeted delivery and gene knockout in vivo. ADAR (adenosine deaminase acting on RNA) disruption stimulates dsRNA sensing pathways and a type I interferon response, which can drive a shift the state of the tumor microenvironments (TMEs) to be immune permissive, overcoming a major barrier to generating an optimal anti-tumor immune response with ICB. TAGE enables gene knockout of ADAR, which has been difficult to drug despite compelling preclinical evidence. Preliminary data with a murine surrogate prototype of TAGE-201, with optimized Ab and CRISPR-Cas, suggests Adar knockout in conjunction with ICB treatment mediates systemic anti-tumor responses in syngeneic murine tumor models that do not respond to ICB alone. This Direct to Phase II project aims to 1) identify a TAGE-201 lead candidate by optimizing RNP architecture and guide RNA components, 2) generate a preclinical data package demonstrating Adar knockout in TME immune cells of a murine tumor after direct local injection with murine surrogate of TAGE-201 (msTAGE-201), anti-tumor efficacy in multiple murine and PDX tumor models, pharmacodynamics effects that align with ADAR biology, and pharmacokinetics and toxicity studies that demonstrates an acceptable safety profile, and 3) conduct an INTERACT meeting with the FDA to present the preclinical, manufacturability assessment, and preliminary formulation data packages and an IND-enabling study plan. Upon successful completion of the Direct to Phase II project, the TAGE-201 development candidate will be poised to initiate IND-enabling studies, followed by clinical trials, with the goal to provide an effective treatment option for a population of patients that currently do not have FDA-approved therapeutic strategies to improve overall outcomes and quality of life.