The promise of allogeneic cell therapy has always been scale. Unlike autologous approaches, which require manufacturing a unique product for every patient, allogeneic therapies use donor-derived cells that can in principle be produced in large batches and stored for immediate use. The biological and logistical appeal is clear. The manufacturing reality has been considerably harder to realize.
Arnaud Lacoste, CEO and Chief Scientific Officer of Aurion Biotech, has spent more than a decade working through that challenge. Aurion's program targets corneal endothelial disease using unmodified allogeneic cells — a modality that is unusual in a field increasingly dominated by genetic engineering — and has achieved something the broader cell therapy field has struggled to demonstrate: consistent manufacturing of enough off-the-shelf cells from a single donor to treat more than 1,000 eyes. Lacoste shared the lessons from that process with DDN.
Why primary human cells are so hard to scale
The starting challenge in Aurion's program is one that applies broadly across regenerative medicine: Most cells in the human body are not built to proliferate outside their native environment, and the ones most relevant to disease are often the least cooperative in culture.
"Corneal endothelial cells are particularly challenging because they are highly specialized, terminally differentiated cells with very limited proliferative capacity in vivo," Lacoste told DDN. "For decades, this led many researchers to believe that meaningful manufacturing scale from a single donor tissue would not be achievable."
The broader field has encountered versions of the same problem across cell types. Translating a promising cell therapy from the laboratory into a commercial product requires manufacturing processes that can reliably reproduce the yield and quality achieved at small research and development scales. That gap has repeatedly slowed the progression of compelling preclinical programs.
What compounded the difficulty for Aurion was that the answer could not be found in adapting existing tools. "Many early cell therapy approaches relied on manufacturing processes that were difficult to standardize across operators, facilities, or donors," Lacoste said. "Historically, one of the biggest barriers across cell therapy manufacturing has been the dependence on processes that were initially optimized for scientific proof-of-concept rather than industrial scalability."
Building manufacturability in from the start
Aurion’s approach was to treat scalability as a design requirement rather than a downstream challenge. That meant solving multiple interconnected problems simultaneously rather than sequentially — identifying starting material with appropriate cell quality and proliferative potential, developing expansion conditions that preserve cellular identity and function during scale-up, implementing analytical methods capable of monitoring quality in real time, and designing workflows capable of operating under commercial good manufacturing practices (GMP) conditions from the outset.
"Scalability cannot be treated as an afterthought in regenerative medicine," Lacoste said. "A holistic manufacturing architecture must be designed into the platform from the earliest stages of development."
For Aurion, the commercial experience in Japan — where the therapy has been available since 2024 — proved to be an important forcing function. "Commercial manufacturing requires a very different level of process robustness, reproducibility, logistics management, and quality systems than small-scale academic production," Lacoste said. Moving from a few successful clinical batches to a reproducible system capable of supporting widespread patient access required the team to confront operational realities that a clinical trial setting can temporarily defer.
The case for working with native biology
The Aurion program is also unusual for a reason that goes beyond scale: The cells are unmodified. In a cell therapy field increasingly oriented toward genetic engineering — viral vector manufacturing, gene editing workflows, transduction optimization — Aurion's approach relies on healthy primary human cells and a transiently administered small molecule, the rho-kinase inhibitor Y-27632, to support engraftment.
That choice was deliberate and rooted in the biology of the eye. The eye's anterior chamber is a relatively immune-privileged environment, and corneal endothelial cells themselves secrete factors that help maintain that privilege and regulate local immune responses. Decades of clinical experience with endothelial keratoplasty procedures — performed routinely without donor-recipient matching — have established that immune rejection is not a major concern in this tissue context.
"Across more than 11 years of clinical experience and hundreds of treated patients spanning Japan, the United States, Canada, and El Salvador, we have observed no instances of immune rejection with this cell therapy," said Lacoste.
"From a manufacturing perspective, avoiding genetic engineering can substantially reduce process complexity," Lacoste continued. "It eliminates the need for viral vector manufacturing, gene editing workflows, transduction optimization, and some of the additional analytical characterization required for engineered products." It also removes a category of regulatory risk: Long-term concerns about insertional mutagenesis or genomic stability are not relevant to an unaltered product.
The tradeoff is that working with unmodified primary human cells places an elevated demand on process control. Without the option to engineer around biological limitations, manufacturing scale and consistency must be achieved entirely through starting material selection, cell biology understanding, and process execution. "In many ways, our approach required us to deeply understand and work with the intrinsic biology of the cells rather than engineering around it," Lacoste said.
The rho-kinase inhibitor plays a supportive role without compromising that principle. "The rho-kinase inhibitor is not genetically modifying the cells or permanently altering their biology," Lacoste said. "Rather, it transiently supports the conditions that help the transplanted cells successfully attach and restore endothelial function." Once engraftment is complete, it clears rapidly — leaving the patient with healthy natural corneal endothelial cells and no persistent foreign material in the eye.
What transfers to the rest of the field
The lessons Lacoste identified from Aurion's scale-up experience are not specific to corneal endothelial disease. Several translate directly to the broader challenge of making allogeneic cell therapy a commercially viable modality at scale.
The first is that the minimum necessary complexity principle should govern platform design. "Every additional layer of complexity introduced into a cell therapy platform, whether through genetic engineering, highly individualized manufacturing, or complicated supply chains, tends to create additional operational and regulatory challenges," Lacoste explained. That does not mean genetic engineering is wrong for indications where it is biologically necessary — it means that complexity should be introduced only where the biology genuinely requires it.
The second is that the therapeutic setting itself should be evaluated for manufacturing feasibility, not just clinical rationale. "The principle of aligning manufacturing feasibility with biological rationale is broadly applicable," Lacoste said. Indications where relatively low cell doses, immune privilege, or favorable engraftment conditions exist create different manufacturing realities than those requiring high doses, systemic delivery, or extensive immune modulation — and those differences should factor into program design from the outset.
The third is that beginning with commercial execution in mind changes what gets built. "Many early-stage companies begin developing cell or gene therapies with teams that have limited direct experience commercializing these types of products at scale," said Lacoste. "As a result, companies often end up trying to design commercial execution around a core platform that has largely been established around academic or early-stage drug development considerations." For programs targeting large patient populations, that approach creates structural problems that are difficult and expensive to solve retrospectively.
"The field is increasingly recognizing that regenerative medicine will ultimately be judged not only by scientific novelty, but by the ability to reliably deliver safe, effective, and accessible therapies to large patient populations," Lacoste added. For cell therapy specifically, that judgment will hinge on whether the manufacturing infrastructure can match the biology — and whether the field has learned to build both at the same time.
