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A Scalable, GMP-Compatible, Autologous Organotypic Cell Therapy for Dystrophic Epidermolysis Bullosa

Gene editing in induced pluripotent stem (iPS) cells has been hailed for enabling new cell therapies for various monogenetic diseases including dystrophic epidermolysis bullosa (DEB). However, manufacturing, efficacy, and safety roadblocks have limited the development of genetically corrected, autologous iPS cell-based therapies. Dystrophic Epidermolysis Bullosa Cell Therapy (DEBCT), is a new generation, Good Manufacturing Practice-compatible (cGMP), reproducible, and scalable platform to produce autologous clinical-grade iPS cell-derived organotypic induced skin composite (iSC) grafts to treat incurable wounds of patients lacking type VII collagen (C7). DEBCT uses a single step, combined, high-efficiency reprogramming, and CRISPR-based genetic correction to generate genome scar-free, COL7A1 corrected clonal iPS cells from primary patient fibroblasts. Validated iPS cells are converted into epidermal, dermal, and melanocyte progenitors with a novel 2D organoid differentiation protocol, followed by CD49f enrichment and expansion to minimize maturation heterogeneity. iSC product characterization by single cell transcriptomics was followed by mouse xenografting for disease correcting activity at 1 month and toxicology analysis at 1-6 months. Culture-acquired mutations, potential CRISPR-off target effects, and cancer-driver variants were evaluated by targeted and whole genome sequencing. iPS cell-derived iSC grafts were reproducibly generated from four recessive DEB patients with different pathogenic mutations. Organotypic iSC grafts onto immune-compromised mice developed into stable stratified skin with functional C7 restoration. Single cell transcriptomic characterization of iSCs revealed prominent holoclone stem cell signatures in keratinocytes and the recently described Gibbin-dependent signature in dermal fibroblasts. The latter correlated with enhanced graftability. Multiple orthogonal sequencing and subsequent computational approaches identified random and non-oncogenic mutations introduced by the manufacturing process. Toxicology revealed no detectable tumors after 3-6 months in DEBCT-treated mice. In conclusion, DEBCT successfully overcomes previous roadblocks and establishes a robust, scalable, and safe cGMP manufacturing platform for the production of a CRISPR-corrected autologous organotypic skin graft to heal DEB patient wounds.