MOP Platform as a Safety Solution for mRNA Vaccines: Addressing the need to avoid myocarditis and pericarditis

On June 25, 2025, FDA approves required updated warning in labeling of mRNA COVID-19 vaccines regarding myocarditis and pericarditis (following vaccination).

Combined Therapeutics has developed one potential solution to the issue of myocarditis and pericarditis. The Multi-Organ Protection (MOP) Platform has the flexibility to target protein expression and prevent off-target expression for mRNA vaccines. CTx has shown in preclinical development that by MOPing the mRNA, antigen expression can be limited to the site of injection and significantly reduced in the heart. This could prevent side effects caused by the expression of the Spike protein in the heart reducing the incidence of myocarditis and pericarditis.

The CTx Multi-Organ Protection (MOP) technology in mRNA enables tissue-specific control of transcript expression. IM administration of canonical mRNA vaccines can lead to extensive systemic biodistribution including key organs such as the heart. Given the presence of COVID-19 vaccine antigen in cardiac tissue and the association of the Spike protein with myocarditis, it is essential to minimize transcript translation in the heart. Our data demonstrated that inclusion of MOP technology in the mRNA constructs enables targeting of transcript translation to the site of injection with significant reduction of protein expression in the heart.