Importance of RNase monitoring during large-scale manufacturing and analysis of mRNA-LNP based vaccines.

Ribonucleases (RNases) are ubiquitous in nature, being able to cleave a wide range of polyribonucleotides. While the presence of microbial and viral contamination in sterile manufacturing is highly studied and controlled, there are no standardized practices for evaluating RNase in the production facility. Since the COVID-19 pandemic, mRNA-LNP based vaccines have become part of routine large-scale manufacturing. The unstable nature of mRNA poses new challenges to safeguard the working efficacy of mRNA - Lipid nanoparticle (LNP) based vaccines or therapeutics, where the presence of RNase in the formulation process could have a profound impact on the mRNA integrity. In this article, lessons learned are presented with respect to the evaluation of RNase contamination during LNP drug product formulation and analysis. Using sensitive detection methods, the potential presence of RNase in the manufacturing of mRNA-LNPs was investigated. Additionally, capillary gel electrophoresis (CGE) data, used to measure mRNA integrity, demonstrate the quality of the active mRNA substance and importance of suitable RNase control strategies. The results and cases presented in this paper should pave the way forward for evaluation and control strategies dedicated to mRNA-LNP based vaccines and therapeutics.

Characterization of BNT162b2 mRNA to Evaluate Risk of Off-Target Antigen Translation.

mRNA vaccines have been established as a safe and effective modality, thanks in large part to the expedited development and approval of COVID-19 vaccines. In addition to the active, full-length mRNA transcript, mRNA fragment species can be present as a byproduct of the cell-free transcription manufacturing process or due to mRNA hydrolysis. In the current study, mRNA fragment species from BNT162b2 mRNA were isolated and characterized. The translational viability of intact and fragmented mRNA species was further explored using orthogonal expression systems to understand the risk of truncated spike protein or off-target antigen translation. The study demonstrates that mRNA fragments are primarily derived from premature transcriptional termination during manufacturing, and only full-length mRNA transcripts are viable for expression of the SARS-CoV-2 spike protein antigen.