Assessment of innate immune response modulating impurities (IIRMI) in synthetic peptide drugs (liraglutide).

Liraglutide for Injection is a GLP-1 analog that stimulates insulin secretion from pancreatic β-cells in a Glucose dependent manner for the treatment of diabetic patients, especially adult patients with type 2 diabetes, to control blood glucose levels. A generic drug of Liraglutide for injection received tentative approval by the FDA on June 21, 2024. Generic Liraglutide (synthesis) was considered to be equivalent to the original brand-name Liraglutide (recombinant), but their manufacturing processes are different. Although synthetic Liraglutide undergo strict impurity control, even trace levels of different innate immune response modulating impurities (IIRMI) may activate innate immunity in peripheral blood mononuclear cells (PBMCs), leading to the expression of cytokines and chemokines, increased antigen uptake, promotion of antigen-presenting cell (APC) processing and presentation, and enhancement of product immunogenicity [1]. Therefore, accurately assessing the IIRMI immunogenic risk of Liraglutide is a key component of immunogenic risk assessment to ensure that its immunogenic risk is similar or lower than branded Liraglutide products. This study utilized PBMC-based assays with fresh PBMC from different volunteers treated with Liraglutide drugs with or without TLR/NOD ligands to evaluate the recent and aged Liraglutide products for their immunogenicity. A method based on PBMC was established to detect IIRMI in synthetic peptide drugs. Using this method, the results showed that despite differences in manufacturing processes between synthetic Liraglutide (generic) and recombinant Liraglutide (branded), there was no statistically significant difference in their immunogenicities. It provides a novel approach for future research on the innate immunogenicity of peptide drug formulations, enabling a broader detection of trace unknown impurities compared to cell line systems.