RiboX Therapeutics is a globally-operated biotech company focusing on discovering and developing fully engineered circular RNA as a therapeutic modality, which offers advantages to address key challenges of mRNA medicines. RiboX has established a plug-and-play circular RNA platform, an ionizable lipid platform, and has unique assets in active targeting LNP under development.

Circular mRNA (CircRNA) has generated substantial interest as a new mRNA therapeutics platform. Here I will discuss a scalable and column-free method for preparing non-immunogenic circular mRNAs. I will also show its applications in immunotherapy and genome editing.

Circular RNAs (circRNAs) are a class of non-coding RNAs that form a covalently closed loop structure, meaning they do not have 5' to 3' polarity or a poly-A tail, unlike linear RNAs. Initially thought to be byproducts of splicing errors, circRNAs are now recognized as important regulatory molecules in various biological processes. They can act as microRNA sponges, regulate transcription, interact with proteins, and potentially even encode peptides in some cases.The therapeutic potential of circRNAs has gained increasing attention due to their stability, abundance, and unique properties.

RNA activation with small activating RNAs can lead to upregulation of transcription in the nucleus resulting in increased mRNA and targeted protein. Such activation is specific and can last about a month This can be applied to many genes down regulated in common conditions such as cancer as well as rare genetic diseases such as sickle cell disease. Bio-distribution can be performed either with a universal or more targeted delivery approach. Wide bio-distribution is suitable in rare genetic diseases as well as with diseases related to the dark genome where the reduced long noncoding RNA is tissue, cell, and status specific.

At Cloverleaf Bio, we are developing a new class of engineered tRNA therapeutics. Our tRNAs target an underappreciated vulnerability of cancer: addiction to high levels of tRNA modifying enzymes. Cloverleaf’s approach to drugging tRNA modifying enzymes uses engineered “trojan horse” tRNAs. The programmability, potency, and specificity of our tRNAs will potentially improve cancer treatment across a range of indications.

We have developed a platform in which we design RNA-encoded programmable genetic “circuits” that detect molecular cues in a cell to specifically express a payload protein in cells that exhibit a particular molecular signature. We applied this platform to the development of our program which entails systemic delivery of lipid nanoparticle (LNP)–encapsulated mRNA-bearing programmable genetic circuitry that selectively expresses a therapeutic payload within target cells.

A CpG-A DNA TLR9 agonist in a virus-like particle, vidutolimod, induces systemic tumor regression as a monotherapy in PD-1 refractory advance melanoma, which is associated with the secretion of IFN-a.  We have now developed native backbone GU-rich RNA TLR7/8 agonists formulated in lipid nanoparticles that are stronger inducers of IFN-a secretion compared to CpG-A DNA, and which show synergy when used in combination. IV delivery of TLR7/8/9 agonists is well tolerated in mice and nonhuman primates, and induces pharmacodynamic biomarkers associated with human clinical response. Plans for clinical development will be discussed.

AIMers are oligonucleotides that engage endogenous ADAR enzymes to induce highly efficient and specific A-to-I RNA base editing. Our recently optimized AIMer design increases the potency, target space, and tissue targeting capabilities of RNA editing. Optimized AIMers support efficient RNA editing in both hepatic and extrahepatic tissues, including the central nervous system, kidney, and lung. We will show that AIMers support RNA editing of disease-relevant targets in multiple tissues.

This talk will discuss the successful purification of human full-length and active ADAR1 and ADAR2 proteins and how it enables mechanistic understanding of oligo mediated RNA editing.

The goal for the next generation of CRISPR-based medicines is the development of potent and safe therapeutics that can be delivered in vivo specifically to the target cells of interest. The mRNA/LNP format is currently showing the most promise to achieve this challenging goal, and various factors can be optimized to enhance performance, including vehicle (lipid composition and targeting elements), cargo (mRNA and gRNA), and analytical method development.