Terminus-specific antibody development and bioanalytical assay validation to quantify active DR10624 in pharmacokinetic studies
Multi-specific drugs play important roles in addressing multi-factorial disease conditions. DR10624 is a first-in-class long acting Fc fusion triple agonist targeting FGF21R, GLP-1R, and GCGR, which has shown promising e
The development of accurate quantification methods for multi-specific drugs like DR10624 is crucial for reliable pharmacokinetic characterization. Accurate quantification of the intact, pharmacologically active form of DR10624 in serum is essential for PK characterization. The researchers developed rabbit monoclonal antibodies that specifically recognize the N- and C-termini regions of DR10624 and strategically paired them for precise quantification. An electrochemiluminescence (ECL) based immunoassay was established and rigorously validated in accordance with regulatory guidelines. Additionally, a preclinical pharmacokinetic study in cynomolgus monkeys was performed to compare drug exposure using different assay formats. The study successfully identified highly specific rabbit monoclonal antibodies that selectively bound to the intact N- and C-termini of DR10624 and effectively neutralized its GLP-1/GCG and FGF21 activities, respectively. Furthermore, the preclinical pharmacokinetic study revealed a marked discrepancy between total and intact DR10624 exposure, indicating in vivo instability and underscoring the need to quantify active drug concentrations. The ECL-based immunoassay was successfully validated across a wide concentration range of 5.00–1,250 ng/mL in serum, confirming its accuracy, precision, selectivity, linearity, absence of hook effect, and stability.