Models of EB: how treatments are tested before clinical trials can go ahead
As gene therapies for Epidermolysis Bullosa secure FDA approvals in 2025 and enter commercial use, the push for reliable preclinical models accelerates to bridge the gap between lab breakthroughs and widespread patient relief.
Key takeaways
- •Recent FDA approvals of Zevaskyn in April 2025 and Vyjuvek's label expansion mark the first major treatments for dystrophic EB, reducing chronic wounds but highlighting the need for better preclinical testing to refine safety.
- •With EB affecting 500,000 people globally and causing severe pain, infections, and early death, delays in model development risk prolonging high mortality rates in severe cases.
- •Tensions arise between costly gene therapies, averaging $600,000 annually, and repurposed drugs in trials like ART-EB, which could offer cheaper alternatives but require rigorous preclinical validation to avoid failures.
Preclinical Models in EB
Epidermolysis Bullosa, a group of rare genetic disorders causing fragile skin that blisters easily, has seen a surge in therapeutic progress. In 2025, the FDA approved Zevaskyn, an ex vivo gene therapy using patient-derived skin grafts to restore collagen VII, essential for skin anchoring. This followed Vyjuvek's 2023 approval, with its label expanded in 2025 to treat infants from birth. These advancements stem from decades of research but underscore the critical role of preclinical models in ensuring treatments advance safely to trials.
Preclinical models, including mouse and cell-based systems, simulate EB's pathology to test therapies before human exposure. Recent studies, such as those using CRISPR-Cas9 in adenoviral vectors, have validated these models for gene editing approaches. Yet, with EB's subtypes varying in severity, models must evolve to capture nuances like inflammation in EB simplex or collagen defects in dystrophic forms. In 2026, ongoing trials like TAMES-02 for EB simplex and ART-EB for repurposed anti-inflammatories rely on these models to predict outcomes.
The real-world impact hits hardest on the estimated 500,000 affected worldwide, including 30,000 in the US. Severe cases lead to chronic wounds covering up to 75% of the body, frequent infections, and squamous cell carcinoma risks rising 70-fold by age 55. Families face $200,000 annual care costs, excluding new therapies. Inaction delays could miss windows for early intervention, where treatments like Zevaskyn show wound healing lasting up to eight years in trials.
Non-obvious tensions include the trade-offs in therapy types: ex vivo methods like Zevaskyn require surgery and offer durable fixes but carry immunosuppression risks, while topical options like Vyjuvek demand weekly applications. Stakeholder divides emerge, with patient groups pushing for faster access amid NICE reviews potentially delaying UK approvals until July 2026, versus regulators demanding robust preclinical data to avert trial failures seen in earlier bone marrow transplants. Surprising data from mesenchymal stem cell studies suggest extracellular vesicles could provide cell-free alternatives, potentially lowering costs and risks.
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