Science-based innovation to manufacture high quality cells challenges central dogma and terminology
Cell and gene therapies are dominating the world of drug development. With the promise of significant breakthroughs to treat diabetes, cancer and congenital conditions, it is no wonder that research and development is predicted to reach $232.5 billion by 2026, up from $186 billion in 2019 according to Evaluate Pharma.
With so much at stake, attention is now shifting to adopting more modern equipment and methods to consistently produce the best cells.
At the core of this trend is replacing outdated legacy manufacturing techniques in which cells are exposed to air — even if meticulously filtered air — and the negative consequences of that. It’s a simple sounding concept.
Since the beginning, good manufacturing practices (GMPs) have been based on the use of cleanrooms and isolators.
However, the industry is moving toward superior alternatives that accomplish what any air environment cannot: better protection of cells from both microbial contamination and chemical toxicity; and better control of the universal critical cell process parameters (temperature, CO2 and O2).
The key is closure, another simple sounding concept.
“Without closure and separation from air, even highly filtered air, protection from microbial contamination in cleanrooms and traditional isolators is dependent on the liberal use of gaseous and liquid chemical microbial biocides. However, they are toxic to the cells too,” says Randy Yerden, a cell biologist and CEO of New York-based BioSpherix.
In GMP, you must prove that they are not harming your cells, which takes tremendous effort. Even then, it is impossible as the damage is often insidious.
“In addition, emerging science tells us that exposure to air, even for short periods of time, can degrade genotypic and phenotypic integrity and contribute to variability in cell populations. It causes suboptimal transients of those three critical cell process parameters,” adds Yerden. “Yet, this is the norm in cleanrooms and traditional isolators.”
If cells are produced in a more favourable environment, you get better cells —both in terms of the number and consistency of cells produced and, most importantly, their therapeutic potency. For these reasons, moving away from legacy facilities, equipment and practices is essential to advance cell-based therapies.
One only needs to read the industry news to see where it’s headed. Take the popularity of presterilised single-use systems (SUSs), which have exploded in use. Keeping cells aseptic inside a presterilised bag, bag/tube assembly or cassette is easy.
There is less cleaning and virtually no biocide needed. Add to that the productive functionality of their associated mechanical devices, including and up to full automation, and it explains why these closed SUS devices are a dominant trend in modernisation.
Some are unifunction SUS devices, designed for one step in production (cell separation). Some are multifunction SUS devices, which do several steps (cell washing and dilution). Some actually do all the steps in production and are fully automated (totifunction SUS devices).
One of the most commercially successful concepts is totifunction SUS devices designed for the automated production of CAR-T cell cancer therapies. Although limited to one specific process, these are truly modern marvels.
However, they don’t necessarily produce the best or most cells. Recent comparability studies from the NIH show surprising results.1
Although the exposure to air is assumed to be minimal, it is not clear how well exposure to suboptimal transients of the critical process parameters — temperature, CO2 and O2 — are avoided. Other variables inherent to each fixed SUS platform might also be suboptimal and significantly influence the final cell product.
“This is the challenge with standardised live cell process automation. Whether it is one step or a few steps, or all the steps in production, an automated process that doesn’t degrade one kind of cell may degrade others,” explains Yerden.
“Automating too early in development is a risk. Only clinical trials can tell if the cell product works. Developers need flexibility until clinical trials prove successful … and canned automation is not usually flexible.”
“In development, only comparability studies can tell if a process change — such as automation — improves or hurts product quality. Thus, unifunction and multifunction SUS devices impose less risk because they do not automate the entire process; however, upstream and downstream steps may still be left exposed to air,” adds Yerden.
Despite the runaway commercial success of automated totifunction SUSs, the obvious upfront limitation is that most cell production processes do not fit in these devices.
“Even if one does fit, will that cell product be clinically effective or will non-obvious inherent limitations compromise the potency? Certain CAR-Ts are effective, thankfully, but the verdict is still out with other cells,” explains Yerden.
New category challenges dogma and terminology
Alternatives are starting to appear that achieve all the required objectives: complete closure, the complete avoidance of air and virtually no limits or constraints upfront or with time. Some are difficult to describe because they do it in a different way. One example is the Xvivo System model X2 from BioSpherix.
As Yerden explains: “Unlike closed SUS devices, the modular X2 is not constrained to any particular process but can accommodate any entire cell production chain — large or small, simple or complex, centralized or distributed, manual or automated.
With interconnected glove chambers, from the outside it looks like an isolator. However, looks don’t tell the whole story. Isolator dogma brings preconceived notions: HVAC connections, filtered air blowing through, thick heavy gloves, etc.
Like a modern car, you really have to look under the bonnet to find out if it is old petrol or new electric.
Unlike any other isolator, the Xvivo System is infinitely configurable with unprecedented plug-and-play modularity. It assembles from a comprehensive library of modular chambers, cochambers and subchambers, interconnecting in all different ways to efficiently close by form and fit around the workflow of any different entire production process, including all analytic, processing and automation equipment.
Cell production often consists of many widely diverse steps. Technicians or industrial robotic arms use the gloves from the outside for manual or mimetic robotic steps, or to tend to the equipment or automation inside.
However, in the context of producing high quality cells by avoiding contamination and toxic chemicals, it is more comparable with SUSs.
“It is not a SUS of any kind, but like a SUS it makes aseptic cell production easy,” says Yerden. “Instead of using presterilised disposables, it self-sanitises the entire internal production environment automatically without risky biocides."
"No biocides may sound like heresy according to GMP dogma, but it works — and the data trumps the dogma. In this regard it could also be called a next-generation or cytocentric isolator.”
Instead of air inside, it is filled with a mix of pure N2, O2 and CO2 gases from tanks. Carbon dioxide and oxygen can be controlled at optimal levels for cells throughout the system, just like an incubator or bioreactor. Temperature can also be controlled, just like an incubator or bioreactor.
“By eliminating the fluctuations and transient exposures to suboptimal temperature, CO2 and O2 usually caused by all the typical exposures to air in cleanrooms or traditional isolators, you always get cells with better consistency and quality. Sometimes radically better,” emphasises Yerden.
Notably most stem cells and primary cultures fresh from the patient do best at low O2 levels, which simulate normal physiologic levels. In fact, it is the only cell manufacturing platform that can optimise this critical parameter at every step of production, simultaneously with physiologic CO2 and temperature.
However, when necessary, you can simulate air without air, inert with 100% nitrogen or chill down to refrigerator temperatures.
Compared with cleanrooms, it reduces facility costs by 90% when you look at total cost of ownership at equivalent production capacity during the facility lifecycle. Extremely low operating cost is the game changer, although many forget to factor that into future facility cost estimates.
“When you do, it brings cGMP cell production within reach of even the smallest companies. Combine that with the speed and flexibility of deployment, multimodal capability owing to closure, an easy path to regulatory approval, risk mitigation and the high quality of the live cell products, it’s next generation regardless of what you call it,” concludes Yerden.