Background:

Conjunctival epithelial stem cell therapy represents a potential and valuable therapeutic option for people suffering from conjunctival disorders. We recently developed a research protocol for the ex vivo cultivation of conjunctival epithelial cells. However, manufacturing and release of any Advanced Therapy Medicinal Product (ATMP) must be designed and planned according to the Good Manufacturing Practices (GMPs) guidelines. GMPs require the development and validation of properly defined manufacturing processes, analysis methods and process validations. Our previous experience with GMP-cultured corneal epithelial stem cells for clinical application on patients with limbal stem cell deficiency led us to set up a protocol for cultivation of conjunctival cells with standards complying with the requests for clinical studies. The major challenge for cell-based products is to develop manufacturing processes while maintaining the critical quality parameters in terms of safety, identity, purity and potency.

Results:

. The manufacturing process was re-designed in order to include all the quality control assays needed for the release of any ATMP, i.e., sterility, morphology, cell viability, dose, cell identity and impurities, potency, lack of pyrogens, mycoplasma and viral detection. Methods and acceptance values were set for all the assays. Quality control assays to evaluate safety and efficacy were also investigated.

Conclusion:

Here, we describe the main phases of the manufacturing process of a conjunctival stem cell-based product to use in clinical applications. Such characterization is crucial for the preparation of documents and dossiers needed by the competent authorities to start a phase I clinical study on patients with conjunctival disorders. The procedure necessary to reach the marketing authorization of such a new cell-based product is still long, but, if reliable and validated, we believe that, in the near future, patients with conjunctival disorders might have a new treatment based on transplantation of autologous cultured conjunctival epithelial stem cells.