666. A Phase-1 Safety Study Protocol for Lentiviral-Mediated COL7A1 Gene-Modified Autologous Fibroblasts in Recessive Dystrophic Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a debilitating genodermatosis caused by loss-of-function mutations in COL7A1, the gene encoding type VII collagen (C7), a protein central to anchoring fibril formation at the dermal-epidermal junction (DEJ). Presently there are no curative treatments for this condition. We have been developing the gene therapy protocol for locally injection of lentiviral mediated COL7A1 gene-modified autologous fibroblasts into the patients with RDEB. Primary fibroblasts were isolated from a 6mm skin biopsy. Cells are expanded and transduced with a GMP compliant lenti-viral vector containing codon optimised COL7A1 gene cDNA under the control of the human PGK promoter. Transduced cells were further expended to reach appropriate cell numbers and cryopreserved until patients are ready. Scale up studies carried out in our GMP compliance laboratory showed C7 expression and stable integration of vector into cells. In-situ immunostaining and western blot analysis confirmed the expression of collagen VII protein (C7) not only in transduced RDEB fibroblasts but also in the culture media, indicating there is secreted C7 from transduced cells.The primary objective of our proposed Phase-I study is to determine the safety and tolerability of treatment with autologous gene modified cells administered to RDEB patients. Fibroblasts expressing codon-optimised COL7A1 will be injected intra-dermally in 5-10 adults with RDEB. The secondary objectives are to assess the efficacy of this treatment and its impact on skin and reversion of gene expression. Each study participant will receive three intradermal injections of ex-vivo transduced autologous fibroblasts expressing codon-optimised COL7A1 as the IMP and three intradermal injections of non-transduced autologous fibroblasts as control. Each injection (both IMP and control) will be administered into separate 1cm2 areas of intact skin sites. Participants will be followed up with study interventions for a total of 36-month period at various time points. If successful, a similar approach could be used to modify autologous epidermal sheets for localised treatment of blisters as well as systemic cell therapies.