三种不同细胞培养工艺成本比较：补料批次、浓缩补料批次和浓缩灌流

An Economic Comparison of Three Cell Culture Techniques: Fed-Batch, Concentrated Fed-Batch, and Concentrated Perfusion

1. Janice A. C. Lim (Bioprocess Consultant) 1. John Bonham Carter (VP Sales)

2. Andrew Sinclair (Managing Director) 2. Jerry Shevitz (President)

Biopharm Services Ltd Refine Technology, LLC

Lancer House, East Street, 26 Chaplin Road, Unit 1107

Chesham HP5 1DG PO Box 691

United Kingdom Pine Brook, NJ 07058, USA

Contact: Andrew Sinclair Contact: John Bonham Carter

Tel: +44 (0) 1494 793 243 Tel: +1 793-993-3003

a.sinclair@ jbonhamcarter@

Photo 1: The operator is handling a ATF6 System in the plant.

Table 1: Guideline working volume sizes for each ATF system

selected nutrients during the growth culture cycle to improve productivity and growth. The culture is subsequently harvested and the product recovered. Fed-batch culture has been an attractive choice for large-scale production due to its operational simplicity and familiarity as a carryover process from fermentation. However, fed-batch mode of operation typically also involves high start-up costs, resulting from the need for larger bioreactor plant capacity.

In perfusion culture, a continuous supply of fresh media is fed into the bioreactor while growth-inhibitory by-products are constantly removed. The increasing interest in the use of perfusion culture can be attributed to the higher product output from a reduced reactor size (hence, simplifying operation, cleaning and sterilization). The cell densities achieved in perfusion culture (30–100 x106 cells/mL) are typically higher than for fed-batch modes (5−25 x106 cells/mL) . The principal aspect of perfusion operation, which is different from fed-batch, is the added requirement of a cell retention device. Cell retention systems add a level of complexity to the process, requiring management, control and maintenance for successful operation. Perfusion bioreactors can suffer operational difficulties such as malfunction or failure of the cell separation device which can lead to shortening of the production run, leading further, to increased operating costs. This has previously limited their attractiveness.

In recent years, a new platform technology has been developed for biologicals production. The ATF™ System, introduced by Refine

Technology, LLC (Pine Brook, NJ). Used in the alternating tangential flow mode, it is a low shear filtration system that inhibits filter-membrane fouling. This external cell-separation system is able to maintain

continuous culture for extended periods of time and offers the capability of rapid filter change without compromising the culture run.The ATF™ System allows increased volumetric productivity and reduced bioreactor size.

Concentrated fed-batch and concentrated perfusion are two production techniques based on the ATF™ System, which simultaneously nourishes the culture and concentrates the product within the bioreactor. These manufacturing methods permit great increases in cell and product concentrations as compared to fed-batch and perfusion. For example in the concentrated fed-batch production platform, one of Refine Technology’s pharmaceutical clients4 has reported a protein product titer of 17g/L with an unoptimized CHO cell process. Higher titers are expected as process

optimization continues. In the concentrated fed-batch operation, ultra high cell densities of (70–200)x106 cells/mL have been achieved; similarly, extremely high cell densities in the region of (70–100)x106 cells/mL have been achieved in systems using the concentrated perfusion mode.

The system scales on a linear basis from 1L to greater than 1,000L and can be used with traditional or disposable bioreactors and with all cell types including anchorage dependent lines. Table 1 indicates the working volume sizes for each ATF™ System in the scale-up process. The figures in the table are provided as guidelines. Actual capacity and vessel size depend upon process conditions.

This article compares the economic feasibility of a typical glycosylated protein manufactured using three production techniques – fed-batch (FB), concentrated fed-batch (CFB) and concentrated perfusion (CP). The Excel-based process-cost modeling tool, BioSolve from BioPharm Services Ltd (Chesham, Buckinghamshire, UK), was used for the economic assessment. The methodology, assumptions and key results of the cost model are described. The analysis will use the cost of goods (CoG) metric expressed on a per gram basis for comparability.