With 30 years of experience manufacturing plasmid DNA (pDNA), Richter-Helm has gained an unparalleled amount of first-hand knowledge that they apply to each customer project, regardless of phase or scale. Richter-Helm’s Managing Director Kai Pohlmeyer, Ph.D., and Director of Business Development Thilo Kamphausen, Ph.D., discuss the company’s upcoming expansion in Bovenau, Germany, how pDNA manufacturing is differentiated from more conventional biomanufacturing, and how to ensure and test for the highest level of quality.
David Alvaro (DA): Can you give me a brief introduction to Richter-Helm BioLogics and the company’s history in the plasmid DNA space?
Thilo Kamphausen (TK): We are a versatile CDMO manufacturing a range of products using microbial fermentation — this not only includes plasmid DNA but also proteins and bacterial vaccines. Plasmid DNA consists of about 30–40% of our current business; we lead the industry in this technology, as we have almost 30 years of experience manufacturing it.
Kai Pohlmeyer (KP): Richter-Helm was one of the first players in pDNA. The company started in 1997 and has continued to gain experience and expertise in pDNA manufacturing. We currently use three to four different processes and a range of scales to accommodate all products. For instance, we conduct feasibility studies at a scale of 1 L or smaller, and we manufacture at 200–1,000 L. Typically, the 200-L scale yields or leads to yields of 5–20 grams, while we can reach yields of more than 100 grams of pDNA with the 1,000-L scale. Different processes yield different scales for different purposes.
DA: What is the range of applications for the plasmids that you manufacture?
KP: Although we produce plasmids for many different applications, we originally began manufacturing plasmid DNA (pDNA) exclusively for vaccines as APIs. However, this has significantly changed over the last six years. We now produce plasmid DNA as critical raw materials for further processing. These plasmids are used as starting materials for virus production, cell and gene therapy, mRNA production, and cell-free expression systems, which are even newer. We also produce a high number of plasmids for API applications in vaccines, and, while none of those applications are currently registered, we’ve produced many batches for phase III and process validation applications.
Looking forward over the near term, I believe the greatest growth in demand will stem from late clinical trials into commercial applications, with the most potential in cell and gene therapy applications.
DA: From the point of manufacturing, are all plasmids fundamentally the same regardless of their ultimate application?
TK: The manufacturing process itself is mostly identical for all plasmids. In most cases, downstream processing involves two-step chromatography, hydrophobic interaction, and then anionic exchange. Both directions and combinations are possible, as the ultimate result is a pure plasmid. The challenge is to produce and identify the highest quality with high-resolution analytics. In addition to being GMP compliant, we’re able to judge the quality of our products with analytical methods that reveal isoforms of up to 98% purity.
KP: We see a lot of players producing high-quality, non-GMP pDNA, and, from the regulatory perspective, it’s possible to use that quality for phase I or phase II trials. Richter-Helm focuses on GMP production of plasmids and intermediates for phase III and commercial materials. Players are increasingly starting phase I and II trials using GMP quality, as we’ve seen a shift from high-quality DNA to GMP-grade DNA.
DA: Is Richter-Helm more focused on custom plasmids rather than more standard, off-the-shelf helper plasmids?
TK: We are fully focused on custom (or “customer”) plasmids. Though we do not have off-the-shelf plasmids, we will manufacture any plasmids a customer requests, regardless of size. This is critical in manufacturing, and we have several processes in place for complex products larger than 10–12 kilo-basepairs (kbp). This flexibility enables us to determine the best option for each specific plasmid. We offer cloning services once only the plasmid is available; we can also contribute cell lines, in most cases DH5α or DH10B. Highly specific cell lines are necessary if you have plasmids that tend to modify.
DA: Is plasmid manufacturing fully standard or are there ongoing challenges, particularly with these larger plasmids that you’re continuing to develop new solutions for?
TK: Our processes are fully scalable from 10 L to 1,000 L, and we select or suggest the right size depending on the corresponding plasmid demand. To assess that, we generally recommend a small-scale feasibility study. While there are variations from project to project, plasmids are generally much more standardized compared with proteins.
KP: We use our generic processes and analytics about 80% of the time for pDNA manufacture, though there are certain challenges, like very long poly-A tails or CG-rich sequences. In these outstanding cases, we optimize the process.
DA: A recurring theme in plasmid DNA for cell and gene therapy has been capacity challenges. Can you help explain why this is?
TK: Building up a facility for microbial manufacturing is complicated and takes time; there is also a high level of commitment needed to qualify for GMP. Demand massively increased due to the pandemic, as most providers decided to expand, which we had strategically done before 2020. I also think the ongoing crunch is a reaction to growing demand — the industry is attempting to compensate for a lack of manufacturing capacity.
KP: Biologics manufacturing was primarily focused on CHO and other mammalian cell culture over the last 30 years, and this accounts for approximately 75% of the existing capacity as that field has grown exponentially. Microbial technologies have always represented the more niche side of the business. Suddenly, however, because of CAR-T therapies, cell and gene therapies, and mRNA, the plasmid DNA market has experienced significant growth. Of course, when building facilities to support this capacity, it takes at least two to four years to become operational, which has created challenges for many.
DA: Can you provide details on the E. coli strains that you work with? What considerations go into selecting the optimal strain for a given plasmid project?
KP: We are using several processes to produce pDNA, each of which has a preferred strain. We can use all the strains that the customer provides us with, though we start each project with a strain selection or strain development approach and compare the yield and the quality of each. Our experience with respect to quality and yield indicates that DH5α and the DH10B are often most optimal, though we do use many others. More complex systems, like the StblTM system, are used to produce more complex sequences. We always start by testing different strains to determine the best process for the existing expression system.
DA: Is development for downstream processing and analytics more straightforward for plasmids than proteins because every plasmid is fundamentally similar?
TK: The analytics themselves aren’t easier, but they can be applied to a broad range of plasmids once developed since the plasmids are very similar. Proteins have to be specifically tested and adapted in more detail. We have a generically validated set of analytical methods that can be easily applied with one test to most of the plasmids in use.
Ion exchange and hydrophobic interaction appear in all plasmid DNA processes, and, compared with proteins, there are three, sometimes four chromatography steps. Impurities are removed after two steps; this is a standardized downstream process that can be used for all plasmids.
KP: Our analytical testing is outstanding, as we have a panel of methods that are all qualified or validated and can be applied easily to every new project -- this saves time and ensures that our plasmids meet the highest quality standards.
DA: Throughout the 30 years that you’ve been working in plasmids, have there been any transformative innovations that have completely changed your approach, or have improvements happened gradually and iteratively?
KP: There have been many gradual improvements. We learn from every project we take on at Richter-Helm, and we made some relevant changes, especially when we began intermediate manufacturing. Before that, we only manufactured APIs; our documentation was too oversized to produce or deliver intermediates or critical raw materials. We were able to reduce this to the necessary minimum, which was a big improvement. Over time, we developed our own manufacturing process, which took five or six years. We have reaped the benefits of this work, as we now have our own process available that we can offer to our customers.
TK: We’ve also made improvements in fermentation technology leading to higher plasmid DNA yields.
DA: Do you foresee any disruptive technologies on the horizon?
TK: I believe there will always be progress in development. In terms of disruptive technologies, we have an eye on the synthetic manufacturing of linear DNA, which could be sufficient for mRNA manufacturing. However, we doubt that it will truly compete with API plasmids.
DA: Among these obviously constant improvements, what are the latest developments at Richter-Helm?
TK: We are expanding and adding new capacity in two areas. We’ve identified that a 200-L fermenter is sometimes too large for certain plasmids. To address this, we are evaluating the installation of a 50-L fermenter to meet the needs of smaller quantity requirements. Even more importantly, we are constructing a new manufacturing facility in Bovenau, Germany. This will enable us to triplicate our capacity by adding two more fermenter lines; we already have the space and the supportive technologies needed to add a third line. This expansion is ongoing, and our goal is to be fully operational by the end of 2023.
DA: Over the longer term, is it relatively likely that you will continue to grow capacity to meet the ongoing demand?
KP: Our plan is to grow via our operations, not through acquisitions or mergers. We are in constant discussions with our customers to ensure we have sufficient capacity available to meet their demands for product launches, and we plan to continue to grow our capacity over the long term.
DA: Were supply chain bottlenecks that were caused by the pandemic felt acutely in pDNA manufacturing?
TK: The shutdown in China impacted all, as masks, cleanroom equipment, and disinfectants were in short supply. Luckily, we did not lose any batches because of this, and the energy to manufacture continuously was very high. Based on the delays in acquiring materials needed for a process, you could figure out what other businesses were using, which is why certain lead times increased in a very apparent way. We reacted by increasing our warehouse backup material and quite openly communicating that we needed longer planning times for the batches to ensure manufacturing could be done.
DA: Has that permanently changed how you approach the supply chain?
KP: To get ahead of a potential shortage, we increased our warehouses and storage capacity. Although this has had a financial impact, we now have a huge stock of materials.
DA: What do you view as the most critical differentiators for Richter-Helm in the pDNA market?
KP: We think there are three main selling points at Richter-Helm. The first is our rich history and experience spanning 30 years. Over that time, we have dealt with many processes, qualities, customers, and authorities, which has helped to build our unique knowledge base. Our second selling point is flexibility. Although we are growing, we operate like a small organization, which enables us to focus fully on our customers’ demands. Our third and perhaps most important selling point is the quality of our products. We provide customers with the highest GMP quality, which has been proven by many authorities and inspections. This triangle of quality, experience, and flexibility differentiates Richter-Helm from all other players. We are also as reliable and transparent as possible thanks to our leading, hands-on project management team.
DA: How important is it for Richter-Helm to be able to support customers on the regulatory side?
TK: Our two main markets are EMA and FDA regulated, as we can completely follow the European pharmacopeia and the USP. We have covered all critical markets with a full, successful GMP system, which is identical to all the GMP operations that we have, independent of the sites. This is an advantage, because we can quickly exchange and interchange operations as we all work following the same system.
DA: Is there a general profile of the kind of companies you’ve worked with in the past or a certain type of organization that you think is the best fit specifically with Richter-Helm rather than another company?
TK: We have tremendous experience with phase III process validation approaches. If a company has a project in transition from late-phase validation to market, that’s a key interval to reach out. Of course, we can run a phase I project up to commercial. While there aren’t many registered plasmid DNA products, we are proud to have already contributed to one of the first cell and gene therapies.
DA: Where would you like to see Richter-Helm positioned five or 10 years in the future?
KP: We will continue to follow the path we’re on. We’ve invested €85 million into our expansion project, and I anticipate nothing but continued success. The idea is to grow by adding customers and products and continue to expand into new facilities to meet ongoing customer demand.
