Comprehensive Physicochemical and Biological Characterization of the Proposed Biosimilar Darbepoetin Alfa, LBDE, and Its Originator Darbepoetin Alfa, NESP.

Background: For regulatory approval, the comparability of a biosimilar product to an originator product should be ensured through thorough physicochemical and biological characterization.

Objective: To evaluate the biosimilarity between LBDE, the proposed biosimilar darbepoetin alfa, and NESP, its originator, we performed a comprehensive physicochemical and biological characterization study.

Methods: Primary and higher-order protein structures were analyzed using Lys-C peptide mapping with liquid chromatography-mass spectrometry (LC-MS), disulfide bond identification, circular dichroism, and fluorescence spectroscopy.

Understanding of decreased sialylation of Fc-fusion protein in hyperosmotic recombinant Chinese hamster ovary cell culture: N-glycosylation gene expression and N-linked glycan antennary profile.

To understand the effects of hyperosmolality on protein glycosylation, recombinant Chinese hamster ovary (rCHO) cells producing the Fc-fusion protein were cultivated in hyperosmolar medium resulting from adding NaCl (415 mOsm/kg). The hyperosmotic culture showed increased specific Fc-fusion protein productivity (q ) but a decreased proportion of acidic isoforms and sialic acid content of the Fc-fusion protein. The intracellular and extracellular sialidase activities in the hyperosmotic cultures were similar to those in the control culture (314 mOsm/kg), indicating that reduced sialylation of Fc-fusion protein at hyperosmolality was not due to elevated sialidase activity.

Effect of culture temperature on erythropoietin production and glycosylation in a perfusion culture of recombinant CHO cells.

To investigate the effect of culture temperature on erythropoietin (EPO) production and glycosylation in recombinant Chinese hamster ovary (CHO) cells, we cultivated CHO cells using a perfusion bioreactor. Cells were cultivated at 37 degrees C until viable cell concentration reached 1 x 10(7) cells/mL, and then culture temperature was shifted to 25 degrees C, 28 degrees C, 30 degrees C, 32 degrees C, 37 degrees C (control), respectively. Lowering culture temperature suppressed cell growth but was beneficial to maintain high cell viability for a longer period.

Characterization of N alpha-acetyl methionyl human growth hormone formed during expression in Saccharomyces cerevisiae with liquid chromatography and mass spectrometry.

We found a new variant of human growth hormone (hGH) from the recombinant hGH expression process in Saccharomyces cerevisiae. The variant was identified as N(alpha)-acetyl methionyl hGH which may be formed by N(alpha)-acetylation of met-hGH during the intracellular expression of hGH in S. cerevisiae.