LAUSR

Perfusion cell culture technologies for the production of therapeuthic recombinant proteins are currently on the rise for diverse applications with the aim of process intensification (Bielser et al., 2018; Chen et al., 2018; Fisher et al., 2018; Jordan et al., 2018). This study reports a unique comparison of low (LS) and high (HS) seeding fed-batch bioreactors, corresponding to traditional and intensified operation using perfusion at the N-1 stage, respectively, with perfusion (PF) bioreactors, using a bispecific conjugated fusion protein as a model. It is found that the gain in daily volumetric productivity compared to the traditional LS fed-batch, increases by a factor 3 with HS and 7 with PF. Critical quality attributes (CQAs) also benefited from the perfusion operation. In particular, levels of clipping, that is the fragmentation of the fusion protein, are significantly reduced compared to both fed-batch operations. In PF the clipping varied between 0.6 and 1.5% while in the LS and HS it reached up to 8.7 and 4.9%, respectively. Aggregate levels were also decreased using PF, while the charge variant distribution was more homogeneous and the glycosylation pattern was also significantly affected. The comparison of LS, HS and PF for the manufacturing of a bispecific conjugated fusion protein reported here highlight some productivity and quality benefits inherent to the nature of continuous processing.