In the vaccine industry, as well as in the broader pharmaceutical industry, expectations for mRNA technology used to be fairly modest. But all that changed with the urgent response to the COVID-19 pandemic. Suddenly, the world witnessed a pair of mRNA breakthroughs. These were, of course, the mRNA vaccines from Pfizer-BioNTech and Moderna.
To the casual observer, these vaccines may have seemed like singular achievements or overnight successes. However, they are part of a larger and older story, one that includes the development of many enabling technologies, including technologies for stabilizing mRNA and for engineering safe and effective liposomes and lipid nanoparticles. Other helpful developments included the adaptation of manufacturing insights from DNA vaccines to mRNA vaccines.
The story continues. That is, the technologies that helped bring about the first mRNA vaccines are inspiring new developments and raising expectations about additional boons. This optimistic take on the future of mRNA technologies is shared by all the experts quoted in this article. They represent a range of companies, and they cite progress in areas such as mRNA construct design and distributed manufacturing. The experts also raise concerns—some old (familiar manufacturing bottlenecks) and others new (unprecedented production challenges).
Bringing mRNA to fruition
The technologies behind mRNA vaccines have a long history. “The trend was definitely established in the mid-2010s toward mRNA therapies and what was required for their development,” says G. Brett Robb, PhD, scientific director for RNA and genome editing at New England Biolabs, a company that specializes in discovering and producing enzymes for molecular biology applications.
Robb points out that New England Biolabs has been supporting the development of mRNA therapeutics since the 1980s by developing and supplying products such as in vitro transcription kits. “Around the 2010s,” he recalls, “we released capping enzymes because we started to appreciate a trend in the research marketplace toward mRNA therapies for various things.”
In recent years, the trend has only been accelerating, given the increased interest in mRNA therapeutics. “As a modality, mRNA has really gained a lot of traction,” Robb affirms. Doubtless, the growing interest in mRNA therapeutics is largely due to the example set by the mRNA vaccines for SARS-CoV-2.
These vaccines progressed from viral sampling to approval more quickly than any other vaccines in history. They also showed impressive speed in entering large-scale production. By the end of 2021, nearly 3 billion mRNA vaccine doses had been manufactured, even though their production depends on lipid nanoparticle encapsulation, a technology new to mass production.
Distributed and modular manufacturing
On-site manufacturing of RNA-based therapeutics and vaccines “is an interesting trend,” Robb says. One manifestation of the trend, he notes, is a $60 million program backed by Wellcome Leap. The program, called RNA Response + Readiness (R3), is designed to encourage a global network of RNA-based biofoundries. When these manufacturing facilities are in place, they will probably need to employ stabilized enzyme formulations. According to Robb, such formulations could promote ease of shipping.
Another popular trend in biomanufacturing is the move to modular manufacturing. “There are lots of articles promoting modular manufacturing,” states Nigel Hall, managing director of WHP, an engineering company that recently finished the design and build of an Oxford Biomedica GMP facility for the large-scale manufacture of AstraZeneca’s COVID-19 vaccine. “But what ‘modular’ means can differ from person to person.”
A modular manufacturing facility covers a large area and eschews fixed equipment. Instead, it relies on equipment that can be swiftly reconfigured to produce a variety of products. Potential advantages include being able to manufacture regionally to overcome border controls and adapt to changing geopolitical situations.
“A complete modular facility is lots of building blocks put together—what we call, ‘boxes in boxes,’” Hall remarks. “But there are lots of different views.”
“We’ve done one of the larger modular facilities,” he continues. “For us, ‘modular’ feels like a bit of a buzz word.”
Modules offer flexibility, but they also occasion compromises. That is, modules need to fit within existing room configurations, accommodate support pillars, and so on. Accordingly, Hall points out that the modular approach may not be the best solution for every vaccine manufacturer interested in building a new facility. For Hall, the important thing is to “make sure that the customer ends up with a good result.”
WHP holds that existing buildings shouldn’t be overlooked, especially in expensive high-density areas. The Oxford Biomedica facility was built in Oxford, inside an old post office sorting building. Another repurposing project by WHP involves fitting a synthetic DNA plant into a former Victorian pumping station in south London.
Benchtop synthesizers
Besides facility-scale innovations, there are benchtop-scale innovations. Consider the emergence of benchtop DNA and mRNA printers. “We’re in the DNA writing business,” says Krishna Kannan, PhD, director of research and development at Codex DNA. He asserts that the Codex DNA BioXp system is the first benchtop system for the synthesis of biopolymers.
Kannan describes how a Codex DNA user can print DNA or mRNA for testing vaccines against viruses such as SARS-CoV-2: To start, the customer inputs a desired sequence into the company’s web portal. Then, three to five days later, the customer receives a kit. Finally, the customer plugs the kit into the BioXp system, initiating a process that takes 16–20 hours to produce, purify, and error-correct the sequence.
“To contextualize this, when people want to test mRNA vaccines, they usually make DNA templates,” Kannan remarks. “These are usually synthesized through a third party. Or people just order mRNA and wait a few months to get it to test.”
After the pandemic began, candidate sequences were needed so urgently that people grew impatient with existing sequence workflows. Indeed, people started to consider the advantages of benchtop devices. According to Kannan, these advantages go beyond the immediate need for speed. He believes that in the future, benchtop mRNA printers could help drive the adoption of decentralized manufacturing.
“With mRNA vaccines, there has to be a cold-chain supply chain, which makes it difficult to reach areas without rapid refrigeration,” he points out. “Our ultimate aim, as a company, is to help make needle-ready mRNA vaccines—where you just place machines anywhere in the world and quash epidemics as they arise.”
Another company offering a benchtop system for DNA printing is DNA Script. This company launched the system last summer and named it Syntax. According to Thomas Ybert, PhD, DNA Script’s founder and CEO, Syntax is fully automated and capable of producing 60-mer oligonucleotides in 13 hours. He adds that Syntax, the company’s first product, “allows life sciences professionals to access DNA on demand.”
Ybert asserts that Syntax is unique in using enzymatic catalysts rather than chemical solvents to synthesize DNA. He explains that the company’s approach, Enzymatic DNA Synthesis (EDS), builds DNA strands much like nature does and presents many advantages over older phosphoramidite chemistry. For example, unlike phosphoramidite chemistry, EDS doesn’t produce toxic organic waste. He declares, “If we’re going to ramp up our RNA/DNA production capabilities, we need to be as green as possible.”
Innovations in mRNA
Variations in the structure of mRNA therapeutics is another emerging trend, according to David Ricketts, PhD, director of business development at eTheRNA. “I think there are going to be lots of new takes on different types of RNA,” he says, “along with new delivery platforms and new formulation technologies.”
Further developments in mRNA technology are likely, he says, “but there’s [also] a growing interest in circular RNA and self-amplifying RNA.” Circular RNAs, or circRNAs, play important roles in cellular processes, and their dysregulation been implicated in many types of disease, including cancer, cardiovascular disease, and neurological disease. CircRNAs are also seen as possible future candidates for SARS-CoV-2 vaccines.
As Robb explains, current antigen-encoding RNAs on the market are linear and incorporate a cap and a tail. He adds that circRNAs are, in contrast, covalently closed and lack free 3′ and 5′ ends. Self-replicating RNAs are long compared to current RNAs, and they may also be useful in the design and development of new vaccines.
Ricketts also predicts innovation in the structure of mRNAs, such as new capping technologies and the use of modified bases such as N1-methylpseudouridine. “The intellectual property is tightly controlled by a small number of companies,” he observes. He adds that he believes companies offering different, cheaper alternatives will expand the marketplace and open new opportunities.
Facing the challenges
“The view in the market is that, since Moderna and Pfizer produced mRNA vaccines in a short space of time, that means it’s easy to do,” Ricketts relates. He argues that a major challenge to the industry is that mRNA vaccines are not yet an easy and straightforward technology platform.
Among the things companies should consider is ensuring that the lipid nanoparticle (LNP) they’re using is matched to their mRNA payload. “You don’t just stick one inside the other,” he insists. “It’s more complex than that.” He recommends, from a contract development and manufacturing organization (CDMO) perspective, that companies “undertake the RNA and LNP formulation side by side, in parallel, and make sure they’re well matched.”
Another issue is a perceived bottleneck in manufacturing capacity for viral vector–based therapies and vaccines. This is a motivation behind a new 15,000-square-meter site built by Exothera, a new CDMO that forms part of life sciences company Univercells.
“The lack of manufacturing capacity, in the United States and in Europe, and even worldwide, was the first reason to set up a new CDMO,” explains Thibault Jonckheere, Exothera’s CEO. He says that the bottleneck, which is already tight because of viral vector–based vaccines against COVID-19, is bound to become even tighter with the arrival of newly approved gene and cell therapies.
The new facility, located 30 minutes from Brussels, will feature two buildings—one for R&D, quality control, and clinical phases of development, and another for large-scale manufacturing. “We want to set up the commercial building from the beginning,” he notes. “Some of our clients transition into commercial phases very fast.”
Exothera describes itself as a mid-sized CDMO, as does eTheRNA, which says that it has—unlike some of the bigger CDMOs—capacity for new therapeutics. “What we’re seeing is that some of the more established CDMOs in the market don’t seem to have the space and pipeline to match customers’ needs for trials—they have a big backlog,” Ricketts maintains. “We’re a smaller company and probably less well known, and we have good availability in our GMP plant.”
Tackling formulation
A final challenge is formulation of mRNA vaccines. “We need to consider we’re not dealing with simple solutions, but with complex formulations where analytical techniques are important to fully characterize them,” advises Vincenza Pironti, PhD, global subject matter expert for sterile drug products at Thermo Fisher Scientific.
Another formulation challenge she identifies is the need to protect sensitive, high-value products. “[Our processes] need to be as well planned and streamlined as possible,” she says, emphasizing details such as minimizing the time vaccines spend at room temperature. (Some vaccines need to be stored at very cold temperatures, such as −60 or −70°C.)
For Pironti, a major trend going forward is the application of digitalization in the planning and streamlining of processes. “Digitalization is important,” she says. “It’s a hot topic in the industry right now.”