Glycosylation Pattern and in vitro Bioactivity of Reference Follitropin alfa and Biosimilars

Recombinant follicle-stimulating hormone (FSH) (follitropin alfa) and biosimilar preparations are available for clinical use. They have specific FSH activity and a unique glycosylation profile dependent on source cells. The aim of the study is to compare the originator (reference) follitropin alfa (Gonal-f (R))- with biosimilar preparations (Bemfola (R) and Ovaleap (R))-induced cellular responses in vitro. Gonadotropin N-glycosylation profiles were analyzed by ELISA lectin assay, revealing preparation specific-patterns of glycan species (Kruskal-Wallis test; p = 0.05; n = 4). Kinetics analysis revealed that intracellular Ca2+ increased upon cell treatment by 4 mu g/ml Gonal-f (R), while equal concentrations of biosimilars failed to induced a response (Kruskal-Wallis test; p 0.05; n = 5). Apart from preparation-specific intracellular Ca2+ increases achieved at supra-physiological hormone doses, all compounds induced similar intracellular responses and steroidogenesis, reflecting similar bioactivity, and overall structural homogeneity