Magnus Schroeder
One challenge for biopharmaceutical companies developing monoclonal antibody (mAb)-based therapeutics, especially smaller biopharmas, is how to rapidly develop and manufacture their lead candidates and obtain approval for an IND or IMPD to progress into clinical trials.
This often requires companies to partner with contract development and manufacturing companies (CDMOs), to develop a stable, clonal cell line and a robust process that will deliver predictable performance from bench scale through to production bioreactor scale. Selecting the right combination of cell line and upstream and downstream operations is critical to achieving high process titers and yields, as well as maintaining critical quality attributes (CQAs), thus ensuring the product conforms to specification and regulatory requirements while being manufactured at a competitive cost of goods (CoGs). Ideally, the process which is developed to supply pre-clinical and early phase clinical drug substance should also provide a ‘line of sight’ through to commercial scale as this builds additional value into the program.
Choosing a Cell Culture Format
Currently, choosing a cell culture process format is driven by the need for speed, low CoGs, and predictable performance. In the past two decades, the industry standard for producing mAbs has been fed-batch cell culture, which enables titers of 2-5 g/L to be routinely achieved. However, the industry is beginning to shift towards next generation processes that use perfusion-based cell culture formats to intensify upstream productivity. Perfusion cell culture processes significantly increase mass output to more than 3 g/L/day, which would be the equivalent of a fed-batch titer of 20 g/L or more. To manage such a large mass output, perfusion processes are often coupled with intensified, continuous downstream processing to reduce process footprint by purifying the product continuously as it is being expressed. A reduced process footprint has the advantage of lower costs due to the ability to significantly reduce plant and equipment size.
Historically, perfusion technology has been used for difficult to express and unstable molecules and processes were often operated at low cell densities and productivities. Today’s intensified perfusion cell culture processes, applied to stable molecules like mAbs, achieve high cell densities for long culture durations by continuously feeding fresh media to the cells while continuously removing mAb product and waste products from the reactor each day. At the heart of the perfusion system is the cell retention device such as a tangential flow filtration filter (TTF) with hollow fiber membranes that allow product-containing cell culture fluid to pass through for downstream processing while retaining the cells inside the reactor.
Benefits of Perfusion Culture
At Just-Evotec Biologics, use of perfusion culture in our clinical and commercial cGMP facilities (Seattle/Redmond, WA) has increased our bioreactor productivity so that we can deliver up to 8 Kg of drug substance mAb in a 500 L bioreactor and 15-days of production and up to 50 kg of drug substance mAb in a 1000 L bioreactor over the course of a 25-day perfusion run (Figure 1).
Figure 1. Comparison of Drug Substance Outputs from Fed-Batch versus Hybrid and Fully Continuous (E2E) Bioreactor Processes
During perfusion cell culture, the cells remain healthy and at high viability for the production duration because fresh media is continuously added, and waste products are continuously removed. Additionally, the product is removed from the bioreactor as it is expressed and shows improved product quality profiles with, for example, lower oxidation and deamidation levels. This is likely due to reduced exposure of the product to cells and cell culture components inside the bioreactor which can potentially degrade the product.
Process Development
At Just-Evotec Biologics, we offer JP3® – our process and product design platform, which is part of our integrated J.Design service (Figure 2). JP3® combines our own high-performance CHO cell line, expression vectors, cell culture media and production processes specifically designed for intensified perfusion culture.
J.DISCOVERY™ identifies superior antibody-based therapeutics via two formats: an in vitro platform using the humanoid antibody library (J.HALSM) and an in vivo hybridoma platform.
J.MD™ is a suite of molecular design services which leverages Abacus™ and other predictive computational tools. Parental antibody sequences are humanized and optimized to enhance manufacturability and stability.
JP3® is a process development platform leveraging high throughput technology to rapidly deliver intensified, continuous manufacturing processes.
J.POD® is our manufacturing facility design which uses modular clean rooms, single-use systems, and intensified continuous process technology.
Figure 2. Just-Evotec Biologics’ integrated J.DESIGN service
Our platform perfusion cell culture process has been used to produce cGMP drug substance for more than 20 clients and has been included in over 10 IND/IMPD filings. The perfusion platform has been developed to generate high titers for our own glutamine synthetase (GS) knockout CHO cell line with proprietary vectors and transposon technology but also supports other cell lines, including Horizon. Additionally, we have developed cell culture media which has been optimized for use in perfusion culture and has cost advantages over commercial fed-batch or perfusion media. Our approach therefore ensures high mass output and predictable bioreactor performance of clonal cell lines, while minimizing raw material costs. Our technology ensures clients have sufficient material to progress rapidly to pre-clinical and FIH studies, and even advance to later phase clinical studies without requiring additional manufacturing batches.
Future Perspective
Biopharmaceutical companies developing mAbs today need predictable process performance to manufacture their biotherapeutics rapidly and affordably for FIH trials, and an accelerated path to commercialization, while at the same time mitigating risk as far as possible. Perfusion cell culture has major operational benefits as it leverages smaller, more cost-efficient, and flexible single-use bioreactors (SUBs) which are housed in modular cleanrooms with ballroom-style facilities to reduce expensive cleanroom space and the overall cGMP facility footprint. When perfusion cell culture is coupled with intensified, continuous downstream processing operations, the resulting facility can deliver the same annual mass output as traditional, larger scale stainless steel commercial facilities. Working with a technology-driven, client-focused partner such as Just-Evotec Biologics, using one of the biopharma industry’s most advanced continuous bioprocessing platforms accepted by the regulatory authorities, accelerates and de-risks clinical development and commercial launch. This helps to deliver mAbs and mAb-like products more efficiently and at a competitive CoGs to ensure that these life changing medicines can become more widely available globally.
Magnus Schroeder, Ph.D. is Vice President Process & Product Development, Just-Evotec Biologics, Seattle, WA, USA. magnus.schroeder@evotec.com
J.POD and JP3 are registered trademarks of Just-Evotec Biologics
J.DISCOVERY, J.MD and Abacus are unregistered trademarks of Just-Evotec Biologics
J.HAL is an unregistered service mark of Just-Evotec Biologics