The biopharma industry is showing steady growth. According to Fortune Business Insights, the global biopharma market is projected to grow from $616.94 billion in 2024 to $1,183.72 billion by 2032, exhibiting a compound annual growth rate of 8.5%.1 And besides growth in the value of the biopharma market, there is growth in the diversity and complexity of biopharma pipelines. As noted in a recent Nature Biotechnology article, new modalities such as antibody-drug conjugates, bispecific proteins, and cell and gene therapies helped push biologics across a key threshold in 2022. For the first time, the number of biologics approvals moved ahead of small-molecule approvals.2 New modalities were also highlighted in a recent IQVIA report, which noted that global funding of biopharma R&D increased to $72 billion in 2023, up from $61 billion in 2022.3
Although all this growth is encouraging, it is also straining global manufacturing capacities. Biopharma manufacturers are under pressure to find innovative platform technologies to bring products to market more quickly; to develop more efficient, productive, and sustainable processes; and to reduce costs. Biomanufacturers have long relied on traditional fed-batch (TFB) bioprocessing as the primary method for producing biologics. Although progress has been made in the last decade to improve the productivity and yields from TFB bioprocessing with better cell culture media and feed strategies, TFB bioprocessing still requires large bioreactor volumes, fixed culture durations, and changeover time between runs.
Upstream intensification addresses process challenges
In response to the limitations of TFB bioprocessing, biomanufacturers are turning to process intensification strategies such as continuous manufacturing, N-1 intensification, and intensified fed-batch, which are enabled by perfusion technologies. Perfusion cell culture maintains cells in a continuous state of growth. The biological product and spent culture media are continuously removed from the bioreactor, while fresh culture media is continuously added to replace it.4
When upstream perfusion is performed with technologies such as alternating tangential flow (ATF) and tangential flow depth filtration (TFDF), cell culture can be maintained for weeks or even months, allowing for constant production and harvest of biologics, which dramatically shortens the production cycle and reduces media consumption. This method not only minimizes the physical footprint of biomanufacturing facilities by reducing the size and number of bioreactors needed, but also enhances process control and product quality.
Process intensification in upstream biomanufacturing has been adopted successfully for diverse molecule types, including monoclonal antibodies, vaccines, and complex proteins, as well as various cell types such as CHO, HEK-293, SF9, Per.C6, iPSC, hPSC, and even cultivated food cells. Key advantages of process intensification include higher cell densities and volumetric productivity, coupled with the economic benefits of reduced cost of goods and smaller facility footprints, all while increasing throughput.
Process intensification can also enhance both sustainability and manufacturing flexibility through the integration of stainless-steel or single-use technologies. The use of perfusion technology has enabled the maintenance of cell densities of 150 million cells/mL for extended periods. With the ability to achieve higher cell densities and maintain them for extended periods, perfusion technology significantly boosts productivity and scalability, addressing the key limitations of TFB bioprocessing and propelling biomanufacturing into a new era of efficiency and effectiveness.
A recent compelling example of the benefits of process intensification is seen in the case of Roche’s strategic use of perfusion technology. Efficiency gains in Roche’s biologics manufacturing resulted in the company’s divestment of a 330,000 L biologics manufacturing facility. (The facility was bought by Lonza, a contract development and manufacturing organization, for $1.2 billion.) Roche projects that its titers, which averaged 1.5 g/L in 2015, will reach 4.8 g/L. With this productivity leap in progress, Roche was able to optimize its manufacturing footprint by realigning facilities closer to key markets in the United States, Europe, and Asia. The company was also able to support its shift toward smaller volume, higher potency new molecular entities. This case study illustrates the benefits of upstream process intensification to boost efficiency and productivity for biomanufacturers.5
Implementation considerations
Although process intensification has been well received and accepted across the industry due to significant improvements in productivity and reductions in cost of goods, there remain important considerations when moving from TFB bioprocessing to intensified cell culture.These include the capital expenditures related to equipment purchases, the time and training needed to complete integration, and the investments in advanced control and monitoring technologies to ensure that continuous processes run optimally. Biomanufacturers also must assess whether the layouts of their facilities are adequate.
The wider adoption of process intensification is also hindered by regulatory requirements. Even as many biomanufacturers adopt intensified upstream processes, only recently have critical regulatory guidelines been available for continuous manufacturing.6 Additionally, implementing improvements for an existing process such as transitioning from a TFB process to a perfusion process is considered switching to a new technology. From a regulatory standpoint, this major change requires extensive process characterization studies and possibly even clinical studies to show equivalence.
If the adoption of upstream process intensification is to become less costly and time-consuming, off-the-shelf and robust cell retention devices paired with automated and advanced controllers are essential. The XCell ATF System from Repligen is a scalable, simple-to-integrate, and proven cell retention technology fit for upstream process intensification. The technology is used at more than 500 sites globally for a variety of molecule types, and it supports more than 40 commercial, regulator-approved processes.
Technology overview
The XCell ATF System integrates linearly scalable cell retention devices with laboratory-scale and manufacturing-scale controllers to enable continuous bioprocessing of cell cultures ranging from 0.5 L to 5,000 L. This scalability allows biomanufacturers to start adoption at laboratory scale and then move to process scale, supporting clinical and commercial manufacturing.
Availability of the cell retention devices in stainless-steel and single-use formats offers flexibility and different cost structures, as well as the ability to interface with glass, stainless-steel, and single-use bioreactors. Single-use systems can significantly reduce the costs associated with set-up, cleaning, sterilization, and validation of these operations, ultimately lowering overall production costs and resource needs. Ease of integration with existing bioreactors and distributed control systems further minimizes the cost, time, and effort required for installation and integration of perfusion equipment, accelerating the transition from TFB processes to intensified perfusion processes.
The XCell ATF System includes four main components. The cell retention device includes a hollow fiber filter attached to a diaphragm pump. The cell retention device features a hollow fiber filter that selectively allows media and target product to pass while retaining cells within the bioreactor. A diaphragm pump, operated by a XCell ATF Controller, circulates the cell suspension between the bioreactor and the filter with bidirectional flow that creates a backflush with each cycle, preventing filter clogging and extending process run times (Figure 1). The XCell ATF controller monitors the flow between the ATF device and the bioreactor and ensures that the diaphragm pump operates at the required flow rate as culture cell density (and viscosity) increases.
Examples of upstream process impact and value
Successful implementation of upstream process intensification requires proof of concept and optimization at small scale, followed by technology transfer and scale-up to pilot and commercial scale. Both the ATF and TFDF technologies have the systems and consumables to support this entire workflow. Two case studies, a monoclonal antibody perfusion scale-up using ATF and a virus perfusion with continuous harvest and clarification using TFDF, highlight how successful implementation can increase titer yield and productivity.
Scientists at the Zurich University of Applied Sciences recently introduced an industry-leading 50-day perfusion process that achieved consistent viable cell densities of over 100 million cells/mL and harvested more than 1 g/L/day of antibody. This achievement was made using a CHO cell line expressing trastuzumab. The process was developed at 2 L and scaled to 50 L. Due to the linear scalability of XCell ATF Technology, comparable results were achieved between scales.
The scientists reported that their perfusion process outperformed a TFB process, providing a 10-fold increase in yield per 50 L batch and a 3-fold increase in space-time yield (g/L/day) (Figure 2). Furthermore, they calculated that based on the current dosing of trastuzumab for the treatment of HER2-positive breast cancer and assuming an 80% downstream yield, more than 2,000 patients could be treated using the harvested product from a 50 L perfusion bioreactor.7
A similar conclusion was reached when McGill University, Max Planck Institute, and Repligen scientists collaborated on a gene therapy application in which perfusion was used with TFDF for the production of recombinant vesicular stomatitis virus–based vectors. The intensified TFDF process achieved infectious virus titers of 5.6–7.5 × 109 TCID50/mL, which is the highest titer reported in the literature to date. The unique TFDF filter enabled cell retention (perfusion), continuous harvest of viral vector, and clarification, simplifying the process (Figure 3). The scientists reported that their intensified BHK-21 processes yielded an 11-fold increase in infectious virus titer and a 5.6-fold improvement in space-time yield compared to the optimized TFB process.8
The increasing complexity and variety of therapeutic modalities, coupled with the need to enhance productivity while reducing costs, requires biomanufacturers to evolve by adopting innovative technology platforms in upstream bioprocessing. TFB processes are giving way to process intensification strategies that not only increase productivity and efficiency but also enhance sustainability. The scalability of perfusion systems and the integration of automated controllers allow adaptation across various production scales, helping to alleviate the significant initial costs associated with such advanced technologies. By investing in these innovative solutions now, biomanufacturers can achieve greater efficiencies, better position themselves to meet future challenges, and maintain competitiveness in the rapidly evolving biopharmaceutical market.
Orjana Terova is sr. director product management upstream bioprocessing (Upstream XCell ATF), Melisa Carpio is director upstream field application scientist, Ian Flaherty is associate director product management (TFDF Systems), Robin Butler is director global strategic marketing upstream bioprocessing, Nico Tuason is associate director global strategic marketing upstream bioprocessing, and Christine Gebski is sr. vice president filtration and chromatography at Repligen.
References
- Fortune Business Insights. Biopharmaceuticals Market Size, Share & Industry Analysis. July 22, 2024.
- Senior M. Fresh from the biotech pipeline: fewer approvals, but biologics gain share. Nat. Biotechnol. 2023; 41: 174–182.
- IQVIA. Global Biopharma R&D Boasts Increased Funding, Productivity and Product Launches in 2023. February 23, 2024.
- Bausch M, Schultheiss C, Sieck J. Recommendations for Comparison of Productivity Between Fed-Batch and Perfusion Processes. Biotechnol. J. 2019; 14: 1700721.
- Stanton D. Roche: Improved biomanufacturing efficiency drove $1.2bn Vacaville sale. BioProcess International. Published online April 26, 2024. Accessed August 7, 2024.
- U.S. Food and Drug Administration. Q13 Continuous manufacturing of drug substances and drug products: Guidance for industry. March 1, 2023.
- Ott V, Ott J, Eibl D, Eibl R. Scaling Fed-Batch and Perfusion Antibody Production Processes in Geometrically Dissimilar Stirred Bioreactors. Processes 2024; 12: 806.
- Göbel S, Pelz L, Silva CAT, Brühlmann B, Hill C, Altomonte J, Kamen A, Reichl U, Genzel Y. Production of recombinant vesicular stomatitis virus-based vectors by tangential flow depth filtration. Appl. Microbiol. Biotechnol. 2024; 108(1): 240.
Improving Viral Vector Production with TFDF Technology
For cell and gene therapy applications, especially ones using a viral vector for the method of delivery (both ex vivo and in vivo), implementing an intensified process can introduce tremendous cost and time savings. Recently, the demand for increased viral vector production has been driven by successful approvals and growing interest in the cell and gene therapy space. Currently, there are well over 1,000 clinical trials being conducted globally employing adenovirus, adeno-associated virus, and lentivirus as delivery vectors (Bulcha et al. Signal Transduct. Target. Ther. 2021; 6: 53).
Current batch processing is characterized by low viral titer production levels, which have led to increasing production volumes to meet demand, and diminishing returns and skyrocketing costs. In addition, the vector production processes require many complex and inefficient steps to separate/harvest as well as purify the vectors. In the case of lentivirus, stability problems also come into play as the viral particles have a very short half-life (8–12 hours at 37°C), which can further reduce titer (Dautzenberg et al. Gene Ther. 2021; 28: 89–104).
Repligen’s KrosFlo TFDF technology, when utilized as part of an intensified process, can greatly increase viral vector yield for both lentivirus (up to 30×) and adeno-associated virus (up to 9×). TFDF technology employs a tubular depth filter with a 2–5 µm average pore size operated in tangential flow filtration mode, allowing nearly 100% passage of large biomolecules (that is, viral vectors) while retaining cells (see the figure in this sidebar). The process enables perfusion and continuous harvest of viral particles all within a single-use, closed-loop system from bioreactor to the collection vessel. While TFDF is still a relatively new technology, it has been successfully used in over 70 laboratory- and pilot-scale gene therapy processes ranging in volume from 1 L to 500 L.
