Antibody therapies have revolutionized modern medicine: they offer highly specific and effective treatments, with applications in oncology and rare diseases. The drawback of current antibody therapies is that they are expensive and must be administered intravenously, which limits widespread use. RNA-based gene therapy is a potential way to encode antibodies to make these treatments more universally affordable and accessible. For example, RNA-based gene therapy is used in the leading COVID-19 vaccines because it is easy to produce rapidly and cost-effectively at large scales. While RNA vaccines or protein replacement therapies have been widely investigated, the application to RNA-encoded antibodies is still in the early development phase. The main challenge is delivering sufficient amounts of RNA to target cells and ensuring the duration of antibody expression is therapeutically relevant. We aim to use self-amplifying RNA (saRNA), a type of RNA that replicates itself in cells, to encode antibodies. saRNA results in higher protein expression than normal RNA using a lower dose of RNA. We hypothesize that by optimizing the formulation saRNA will enable a low-cost, easily administered approach to antibody therapy.