Overcoming the inconsistent cell culture performance caused by single-use bioreactors during scaling-up the manufacturing process for a therapeutic bispecific antibody

Single use technology has been widely used in modern biopharmaceutical process development and manufacturing. However, there are concerns about the adverse effects of disposable materials on bioprocess, product quality and patient safety. Recently, we observed slow cell growth, increased lactate accumulation, and decreased production titer during scaling up a bispecific antibody (BsAb) upstream process from 3 L to 500 L bioreactor. To investigate the phenomenon, we conducted medium incubation and leachable spike-in experiments. We found that cell culture medium incubated in CX5–14 bag caused poor cell culture performance, which was correlated with the concentration of bis(2,4-di-tert-butylphenyl)-phosphate (bDtBPP), a breakdown product of the antioxidant Irgafos®168 in polyethylene film. In addition, when the media were spiked with 0.15 μg/ml or a greater concentration of bDtBPP, slow cell growth and reduced BsAb expression level were observed. In contrast, Aegis5–14 film produced bDtBPP at a level of below detection during medium incubation. Thus, the bispecific-expressing CHO cell line restores normal cell culture performance and production titer when Aegis5–14 single-use bioreactor was employed in large-scale manufacturing. Our results reveal the importance of evaluating leachable profiles from disposable materials during process development of bispecifics and other novel therapeutic modalities.