Safety and Wound Outcomes Following Genetically Corrected Autologous Epidermal Grafts in Patients With Recessive Dystrophic Epidermolysis Bullosa.
Recessive dystrophic epidermolysis bullosa (RDEB) is a devastating, often fatal, inherited blistering disorder caused by mutations in the COL7A1 gene encoding type VII collagen. Support and palliation are the only current therapies.



To evaluate the safety and wound outcomes following genetically corrected autologous epidermal grafts in patients with RDEB.



Single-center phase 1 clinical trial conducted in the United States of 4 patients with severe RDEB with a measured area of wounds suitable for grafting of at least 100 cm2. Patients with undetectable type VII collagen keratinocyte expression were excluded.



Autologous keratinocytes isolated from biopsy samples collected from 4 patients with RDEB were transduced with good manufacturing practice-grade retrovirus carrying full-length human COL7A1 and assembled into epidermal sheet grafts. Type VII collagen gene-corrected grafts (approximately 35 cm2) were transplanted onto 6 wounds in each of the patients (n = 24 grafts).



The primary safety outcomes were recombination competent retrovirus, cancer, and autoimmune reaction. Molecular correction was assessed as type VII collagen expression measured by immunofluorescence and immunoelectron microscopy. Wound healing was assessed using serial photographs taken at 3, 6, and 12 months after grafting.



The 4 patients (mean age, 23 years [range, 18-32 years]) were all male with an estimated body surface area affected with RDEB of 4% to 30%. All 24 grafts were well tolerated without serious adverse events. Type VII collagen expression at the dermal-epidermal junction was demonstrated on the graft sites by immunofluorescence microscopy in 9 of 10 biopsy samples (90%) at 3 months, in 8 of 12 samples (66%) at 6 months, and in 5 of 12 samples (42%) at 12 months, including correct type VII collagen localization to anchoring fibrils. Wounds with recombinant type VII collagen graft sites displayed 75% or greater healing at 3 months (21 intact graft sites of 24 wound sites; 87%), 6 months (16/24; 67%), and 12 months (12/24; 50%) compared with baseline wound sites.



In this preliminary study of 4 patients with RDEB, there was wound healing in some type VII collagen gene-corrected grafts, but the response was variable among patients and among grafted sites and generally declined over 1 year. Long-term follow-up is necessary for these patients, and controlled trials are needed with a broader range of patients to better understand the potential long-term efficacy of genetically corrected autologous epidermal grafts.



clinicaltrials.gov Identifier: NCT01263379.
Department of Dermatology, School of Medicine, Stanford University, Stanford, California.
Zurab
Z
Siprashvili
Department of Dermatology, School of Medicine, Stanford University, Stanford, California.
Ngon T
NT
Nguyen
Department of Dermatology, School of Medicine, Stanford University, Stanford, California.
Emily S
ES
Gorell
Department of Dermatology, School of Medicine, Stanford University, Stanford, California.
Kylie
K
Loutit
Department of Dermatology, School of Medicine, Stanford University, Stanford, California.
Phuong
P
Khuu
Lucile Packard Children's Hospital, Stanford University, Stanford, California.
Louise K
LK
Furukawa
Lucile Packard Children's Hospital, Stanford University, Stanford, California.
H Peter
HP
Lorenz
Department of Dermatology, School of Medicine, Stanford University, Stanford, California3Now with Department of Dermatology, University of Pennsylvania, Philadelphia.
Thomas H
TH
Leung
Shriners Hospital for Children, Portland, Oregon.
Douglas R
DR
Keene
Department of Dermatology, School of Medicine, Stanford University, Stanford, California.
Kerri E
KE
Rieger
Department of Dermatology, School of Medicine, Stanford University, Stanford, California5Veterans Affairs Medical Center, Palo Alto, California.
Paul
P
Khavari
Department of Dermatology, School of Medicine, Stanford University, Stanford, California.
Alfred T
AT
Lane
Department of Dermatology, School of Medicine, Stanford University, Stanford, California.
Jean Y
JY
Tang
Department of Dermatology, School of Medicine, Stanford University, Stanford, California5Veterans Affairs Medical Center, Palo Alto, California.
M Peter
MP
Marinkovich
D000293:Adolescent; D000328:Adult; D024143:Collagen Type VII / Q000235:genetics* / Q000378:metabolism / Q000627:therapeutic use; D016108:Epidermolysis Bullosa Dystrophica / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D018014:Gene Transfer Techniques; D006801:Humans; D015603:Keratinocytes / Q000637:transplantation*; D008297:Male; D008979:Moloney murine leukemia virus / Q000235:genetics; D011743:Pyrimidines; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism / Q000627:therapeutic use; D013524:Surgical Flaps; D013997:Time Factors; D014945:Wound Healing; D014947:Wounds and Injuries / Q000378:metabolism / Q000628:therapy; D055815:Young Adult
C569053:COL7A1 protein, human; D024143:Collagen Type VII; D011743:Pyrimidines; D011994:Recombinant Proteins; C483405:octahydropyrido(1,2-c)pyrimidine