ESCAPE - Enhanced nanoformulation based on layer-by-layer polyelectrolyte submicroparticles conjugated with cationic peptides

Although mRNA has been explored as a gene delivery strategy for several decades, and several companies have been established around the mRNA vaccine development, its use as a vaccination platform only burgeoned in the past few years thanks to the tremendous success of the COVID-19 vaccines. This success can be attributed to several factors including a longstanding experience with mRNA manufacturing and clinical use in various settings, the availability of suitable carriers under the form of lipid nanoparticles (LNPs) and a relatively stable viral genome in SARS-CoV-2 compared to other viruses such as influenza and HIV. However, although mRNA-based vaccines
Template application PoC-projects – 2nd call 2023
have clearly proven their potential in the COVID-19 pandemic, this does not mean that it represents a one-size-fits-all solution for all kinds of diseases. Although we have probably learned more about mRNA-based vaccines during the last three years than during the three decades before, it is clear that other, more complex diseases such as HIV and cancer, require more elaborate approaches for mRNA to be successful in the treatment of these diseases. Next to the judicial choice of the targets encoded by the mRNA, one of the most important issues is the context of delivery of the mRNA, which in large part is determined by the nanoparticles in which it is formulated. Although LNPs have proven to be a suitable mRNA delivery system in the context of COVID-19, they also have clear limitations, including storage and handling requirements with an important cold chain, requiring ultralow temperatures for long-term storage, the lack of functionalization, as the fluid aspect of LNPs severely limits the type of molecules that can be incorporated, a relatively high cost, limited amount and size of mRNA to be formulated, and uncontrolled immune responses. Based on a longstanding expertise with the development of mRNA based therapeutic vaccines against HIV, our laboratory has evaluated several candidate nanoparticles that could potentially overcome some of the issues related to LNPs. Thus, by combining cationic peptides, a formulation which we previously established in the lab as an excellent carrier for mRNA, with the so-called layer-by-layer (LbL) approach, where layers of cationic and anionic moieties are interchangeably deposited on a calcium carbonate core, like the layers of an onion, we showed that this formulation has many advantages over LNPs: it is cheap and easy to produce, and has potential for upscaling, it is very stable, even at room temperature, thus potentially overcoming important cold chain issues, it efficiently transfects many different cell lines, including dendritic cells, with different kinds of mRNA, including self-amplifying RNA which is very large and difficult to formulate. Finally, a very important asset is the flexibility in functionalizing these nanoparticles, as various organic or inorganic molecules can be incorporated in the core, between the layers or on the outer layer. These include targeting signals, adjuvants, small molecule drugs, fluorophores for in vivo imaging, and even light or magnetic field triggered release of cargo. In this PoC project, we want to further improve our formulation by systematically permutating the different components (core, layers and outer layer) with the aim to develop a flexible mRNA vaccine delivery platform, that can be used for various indications, not only in a prophylactic setting but also as a therapeutic vaccine in difficult to treat diseases such as cancer and HIV infection. In this way we want to strengthen our intellectual property position and bring our formulation closer to the market and to the clinic.