“The biology of aging guides our science — but regulatory conversations are about patient benefit and clinical outcomes. Framing is critical.”
Eric Leire is CEO of GenFlow Biosciences, a Belgian biotech developing gene therapy-based interventions targeting age-associated diseases via the SIRT6 longevity pathway. He has led the company since its founding in 2020 and brings executive experience across multiple European and North American biotech ventures.
GenFlow sits at one of the most operationally demanding intersections in drug development: early-stage gene therapy, a novel biology platform, and a regulatory category — longevity — that doesn’t yet exist in any official pharmacopoeia. This interview covers GenFlow’s manufacturing strategy, the realities of finding capable CGT partners in Europe, and why the company moved away from viral vectors toward mRNA-LNP delivery.
The Scale-Up Problem Is Not a Science Problem — It’s a Timing Problem
Every early-stage biotech CEO says their therapy “works beautifully in the lab.” The harder question is when to stop optimizing and start industrializing.
“Locking the process early enough to move quickly, but late enough to ensure true scalability, is a constant balancing act,” he says. Gene therapies are highly sensitive to process variables — cell line behavior, transfection conditions, and the specific parameters of each purification step. Those sensitivities only increase as you scale.
Lock too early and you’re committing to a process that may not translate to GMP scale. Lock too late, and you’re delaying IND-enabling work, burning runway, and creating CMC package gaps that will come back in regulatory review.
Eric’s framing, “robust, reproducible, and regulator-ready,” is a useful checklist for evaluating whether your own process definition is actually fit for outsourcing, or just fit for the lab.
Finding a CGT CDMO in Europe: Capability Exists, True End-to-End Readiness Does Not
The European CGT CDMO landscape has matured considerably over the past five years. Belgium in particular has developed a credible cluster of gene therapy manufacturing expertise, says Eric. But he is direct about the gap that remains: “Demand still outstrips true end-to-end CGT capability, especially when flexibility, scientific depth, and GMP readiness are all required.”
GenFlow experienced the harder version of this directly. A Belgian partner went bankrupt mid-engagement, forcing a supplier transition at a point in development when continuity matters most. “That experience reinforced how important alignment and communication are — not just technical specifications,” Eric says.
The lesson is that technical qualification alone is insufficient due diligence. A CDMO’s financial stability, its ownership structure, its order book concentration, and the depth of its management team are all relevant inputs to a supply risk assessment in a sector where a single site failure can set a program back 12 to 18 months.
When Viral Vectors Aren’t the Right Answer: GenFlow’s mRNA-LNP Pivot
The CGT sector’s viral vector supply problem is well-documented. Demand for AAV manufacturing capacity has outpaced available GMP slots for years, and pricing for viral vector CDMO work has reflected that imbalance. Eric acknowledges that the problem had a direct effect on GenFlow’s manufacturing strategy.
“It’s one of the reasons we are moving toward non-viral delivery approaches,” he says. But the decision wasn’t purely supply-driven. For GenFlow’s programs, particularly in MASH, sarcopenia, and glaucoma, the biology pointed toward a different conclusion about delivery. “Given the need for repeated administrations, we found that an mRNA–LNP strategy is a better fit for our programs than AAV-based delivery.”
Regulatory Strategy for a Disease That Doesn’t Officially Exist
Longevity biotech occupies an unusual regulatory position. Aging is not a recognized disease indication at the FDA or EMA. Companies targeting the biology of aging must therefore construct regulatory strategies around specific age-associated conditions, and do so in a way that keeps the scientific rationale intact without creating a pathway that regulators can’t act on.
“Regulators may approve aging itself one day. In the meantime, we focus on clearly defined, age-associated indications with measurable clinical endpoints — such as MASH, sarcopenia, or glaucoma,” explains Eric.
Each of those indications has an established regulatory pathway, accepted biomarkers, and existing clinical trial precedent. The biology of SIRT6, GenFlow’s core target, links to each of them mechanistically. The science and the regulatory strategy are aligned, but they operate on different vocabularies.
Where the Industry Is Heading
Eric’s perspective on longevity biotech points to something wider than GenFlow’s specific programs. The diseases of aging, including MASH, sarcopenia, neurodegeneration, and metabolic dysfunction, are among the highest-burden conditions globally, and they share an underlying biology that gene therapy and RNA-based medicines are increasingly well-positioned to address. The companies that will bring these programs to patients are the ones that treat CMC not as a late-stage obligation but as a strategic variable from day one.
Longevity biotech isn’t always understood for what it actually is. “It’s not about vanity or living forever,” Eric says. “In reality, it’s about resilience—helping people stay healthier, functional, and independent for longer. Our goal is to increase healthspan first, before lifespan — helping people stay healthier, functional, and independent for longer.”
