Comparable Immune Function Inhibition by the Infliximab Biosimilar CT-P13: Implications for Treatment of Inflammatory Bowel Disease.

BACKGROUND AND AIMS: CT-P13 is the first biosimilar monoclonal antibody to infliximab, and was recently approved in the European Union, Japan, Korea, and USA for all six indications of infliximab. However, studies directly assessing the biologic activity of CT-P13 versus inflximab in the context of inflammatory bowel disease [IBD] are still scanty. In the present study, we aimed to compare the biological activities of CT-P13 and infliximab with specific focus on intestinal cells so as to gain insight into the potential biosimilarity of these two agents for treatment of IBD. METHODS: CT-P13 and infliximab were investigated and compared by in vitro experiments for their neutralisation ability of soluble tumour necrosis factor alpha [sTNFα] and membrane-bound tumour necrosis factor alpha [mTNFα], suppression of cytokine release by reverse signalling, induction of regulatory macrophages and wound healing, and antibody-dependent cell cytotoxicity [ADCC]. RESULTS: CT-P13 showed similar biological activities to infliximab as gauged by neutralisation of soluble TNFα, as well as blockade of apoptosis and suppression of pro-inflammatory cytokines in intestinal Caco-2 cells. Infliximab and CT-P13 equally induced apoptosis and outside-to-inside signals through transmembrane TNFα [tmTNFα]. Moreover, regulatory macrophage induction and ensuing wound healing were similarly exerted by CT-P13 and infliximab. However, neither CT-P13 nor infliximab exerted any significant ADCC of ex vivo-stimulated peripheral blood monocytes or lamina propria mononuclear cells from IBD patients. CONCLUSIONS: These findings indicate that CT-P13 and infliximab exert highly similar biological activities in intestinal cells, and further support a mechanistic comparability of these two drugs in the treatment of IBD.

Scalable production of adeno-associated virus type 2 vectors via suspension transfection.

Vectors derived from adeno-associated virus type 2 (AAV2) are promising gene delivery vehicles, but it is still challenging to get the large number of recombinant adeno-associated virus (rAAV) particles required for large animal and clinical studies. Current transfection technology requires adherent cultures of HEK 293 cells that can only be expanded by preparing multiple culture plates. A single large-scale suspension culture could replace these multiple culture preparations, but there is currently no effective co-transfection scheme for generating rAAV from cells in suspension culture. Here, we weaned HEK 293 cells to suspension culture using hydrogel-coated six-well culture plates and established an efficient transfection strategy suitable for these cells. Then the cultures were gradually scaled up. We used linear polyethylenimine (PEI) to mediate transfection and obtained high transfection efficiencies ranging from 54% to 99%, thereby allowing efficient generation of rAAV vectors. Up to 10(13) rAAV particles and, more importantly, up to 10(11) infectious particles were generated from a 2-L bioreactor culture. The suspension-transfection strategy of this study facilitates the homogeneous preparation of rAAV at a large scale, and holds further potential as the basis for establishing a manufacturing process in a larger bioreactor.

High-level scu-PA production by butyrate-treated serum-free culture of recombinant CHO cell line.

The MGpUK-5 cell line, transformed with a single-chain urokinase-type plasminogen activator (scu-PA) minigene, generated mRNA transcripts and scu-PA titers corresponding to 65% or 86% of the amount generated before serum-free adaptation, despite significant loss of scu-PA gene copies during adaptation to serum-free culture. To further augment scu-PA production, a culture strategy employing sodium butyrate was explored. In 60-mL spinner flask cultures, sodium butyrate in the concentration range 1-10 mM allowed scu-PA production 2- to 3-fold higher than that in the negative control culture. Its productivity-enhancing activity was dependent on cell density in a range of 1-5 x 10(6) cells/mL, generating 72,200 +/- 8,100 IU/mL (480 +/- 50 mg/L) in 60-mL spinner flask cultures. To confirm this result, cells were grown to 4.4 x 10(6) cells/mL and treated with 5 mM sodium butyrate in a 2.5-L perfusion culture. The scu-PA titer increased more than 2-fold, and specific production rate of scu-PA increased 3-fold by this treatment. Overall, this perfusion culture gave rise to 1.7 x 10(8) IU scu-PA (1.1 g), comparable to total scu-PA production in a batch butyrate-treated culture performed at a 25-L bioreactor scale (1.3-3.5 g). Our results suggest that sodium butyrate treatment on high-density culture enables scu-PA production in gram quantities.