Comparison of RT-qPCR With Branched DNA to Quantify a Lipid Nanoparticle-Encapsulated mRNA Therapeutic in Serum and Liver Tissue Samples From Nonclinical PK Studies

Accurate bioanalytical methods are essential for characterizing the pharmacokinetics of lipid nanoparticle (LNP)-encapsulated mRNA therapeutics. This study compared reverse transcription-quantitative PCR (RT-qPCR) against the established branched DNA (bDNA) assay for quantifying an LNP-encapsulated mRNA therapeutic encoding human phenylalanine hydroxylase in serum and liver tissue from nonclinical mouse studies, with pharmacokinetic parameters calculated using Phoenix WinNonlin. Both assays showed acceptable accuracy and precision, and while RT-qPCR serum concentrations ran two- to four-fold lower than bDNA measurements, tissue results were comparable, with Bland-Altman analysis confirming close agreement between platforms. The findings support RT-qPCR as a viable, widely accessible alternative to bDNA for quantifying mRNA-LNP therapeutics in future studies.