Title: Potential of Systemic Allogeneic Mesenchymal Stromal Cell Therapy for Children with Recessive Dystrophic Epidermolysis Bullosa
Abstract: TO THE EDITOR The skin fragility disorder, recessive dystrophic epidermolysis bullosa (RDEB) results from mutations in COL7A1, leading to reduced or absent type VII collagen (C7) and defective anchoring fibrils at the dermal–epidermal junction (Fine et al., 2014Fine J.D. Bruckner-Tuderman L. Eady R.A. et al.Inherited epidermolysis bullosa: updated recommendations on diagnosis and classification.J Am Acad Dermatol. 2014; 70: 1103-1126Abstract Full Text Full Text PDF PubMed Scopus (627) Google Scholar). Currently, there is no cure, and most individuals develop life-shortening squamous cell carcinomas (Fine and Mellerio, 2009Fine J.D. Mellerio J.E. Extracutaneous manifestations and complications of inherited epidermolysis bullosa: part II. Other organs.J Am Acad Dermatol. 2009; 61: 387-402Abstract Full Text Full Text PDF PubMed Scopus (166) Google Scholar). RDEB also has a major health economic burden; wound dressings for a 10-year-old child can cost $680 per day (Kirkorian et al., 2014Kirkorian A.Y. Weitz N.A. Tlougan B. et al.Evaluation of wound care options in patients with recessive dystrophic epidermolysis bullosa: a costly necessity.Pediatr Dermatol. 2014; 31: 33-37Crossref PubMed Scopus (16) Google Scholar), which equates to >$250,000 annually. Reported clinical trials of cell-based therapies for RDEB comprise intradermal allogeneic fibroblasts (Petrof et al., 2013Petrof G. Martinez-Queipo M. Mellerio J.E. et al.Fibroblast cell therapy enhances initial healing in recessive dystrophic epidermolysis bullosa wounds: results of a randomized, vehicle-controlled trial.Br J Dermatol. 2013; 169: 1025-1033Crossref PubMed Scopus (96) Google Scholar; Venugopal et al., 2013Venugopal S.S. Yan W. Frew J.W. et al.A phase II randomized vehicle-controlled trial of intradermal allogeneic fibroblasts for recessive dystrophic epidermolysis bullosa.J Am Acad Dermatol. 2013; 69: 898-908Abstract Full Text Full Text PDF PubMed Scopus (80) Google Scholar), bone marrow transplantation (Wagner et al., 2010Wagner J.E. Ishida-Yamamoto A. McGrath J.A. et al.Bone marrow transplantation for recessive dystrophic epidermolysis bullosa.N Engl J Med. 2010; 363: 629-639Crossref PubMed Scopus (266) Google Scholar), intradermal bone marrow–derived mesenchymal stromal cells (BM-MSCs) (Conget et al., 2010Conget P. Rodriguez F. Kramer S. et al.Replenishment of type VII collagen and re-epithelialization of chronically ulcerated skin after intradermal administration of allogeneic mesenchymal stromal cells in two patients with recessive dystrophic epidermolysis bullosa.Cytotherapy. 2010; 12: 429-431Abstract Full Text Full Text PDF PubMed Scopus (133) Google Scholar), and intravenous BM-MSCs in RDEB adults (El-Darouti et al., 2013El-Darouti M. Amin F.M. Abdel Hay R. et al.Allogeneic Bone marrow derived mesenchymal stem cells for the treatment of dystrophic epidermlysis bullosa. The European Society for Gene and Cell Therapy and the Spanish Society for Gene and Cell Therapy.Hum Gene Ther. 2013; 24: A54Google Scholar; abstract only). Ex vivo COL7A1 keratinocyte gene therapy is also being evaluated (Siprashvili et al., 2014Siprashvili N.N. Gorell E. Khuu P. et al.Phase I clinical trial of genetically corrected autologous epidermal keratinocytes for recessive dystrophic epidermolysis bullosa.J Invest Dermatol. 2014; 134: S75Google Scholar). MSCs are heterogeneous cells that undergo self-renewal or differentiate into mesenchymal lineages (Caplan, 1991Caplan A.I. Mesenchymal stem cells.J Orthopaed Res. 1991; 9: 641-650Crossref PubMed Scopus (3495) Google Scholar). MSCs also have non-progenitor functions in immune regulation, cell growth, and tissue repair (Phinney and Prockop, 2007Phinney D.G. Prockop D.J. Mesenchymal stem/multipotent stromal cells: the state of transdifferentiation and modes of tissue repair—current views.Stem Cells. 2007; 25: 2896-2902Crossref PubMed Scopus (1555) Google Scholar; Chen et al., 2008Chen L. Tredget E.E. Wu P.Y. et al.Paracrine factors of mesenchymal stem cells recruit macrophages and endothelial lineage cells and enhance wound healing.PLoS One. 2008; 3: e1886Crossref PubMed Scopus (1253) Google Scholar). Nevertheless, healing is not associated with large numbers of therapeutic MSCs in injured tissues, suggesting that paracrine benefits may modulate inflammatory and immune responses (Baraniak and McDevitt, 2010Baraniak P.R. McDevitt T.C. Stem cell paracrine actions and tissue regeneration.Regen Med. 2010; 5: 121-143Crossref PubMed Scopus (602) Google Scholar). Our interest focuses on the potential of intravenous allogeneic BM-MSCs to help people living with RDEB. Ten children were included in the clinical trial and are detailed in Supplementary Table S1 online, with the trial protocol shown in Supplementary Figure S1 online. The trial was approved by the UK Medicines and Healthcare Products Regulatory Agency, with EudraCT number: 2012-001394-87; the UK National Research Ethics Committee London-Bloomsbury provided ethics approval (Ref:12/LO/1258), and the trial was registered prospectively with www.controlled-trials.com ISRCTN46615946. Written informed consent was obtained for each subject. Inclusion/exclusion criteria are presented in Supplementary Table S2 online, and study interventions are listed in Supplementary Table S3 online. Details of the BM-MSCs are provided in Supplementary Table S4 online. Each participant received three intravenous infusions of BM-MSCs (day 0, 7, and 28; each dose 1–3 × 106 cells kg–1) with no HLA matching or pre-conditioning. Download .pdf (.42 MB) Help with pdf files Supplementary Material With regard to safety, there were 163 adverse events (AEs; Supplementary Tables S5–S7 online). Initially, two serious AEs, esophageal dilatation and skin infection, were reported but were subsequently downgraded (protocol version 4.0, 1 August 2014), as they were considered to be complications of RDEB and not the cells. Indeed, 127/163 (78%) of AEs were either unlikely or not related to the BM-MSCs. Concerning the severity of MSC-related AEs, there were two severe events of DMSO odor, although odor was noted following 28/30 infusions (lasting up to 48 hours). Mild nausea occurred during two infusions, and abdominal pain and bradycardia were observed during two other infusions; all resolved within 15 minutes without treatment or hemodynamic compromise. No AEs resulted in discontinuation of MSCs. Laboratory assessments did not reveal any adverse impact of the BM-MSCs on renal, liver, or bone marrow function. Anti-C7 antibodies were detected by ELISA at baseline in 9/10 participants, but no sera bound to the dermal–epidermal junction by indirect immunofluorescence microscopy. Following MSCs, there were no changes in ELISA or indirect immunofluorescence microscopy data (Supplementary Table S8 online). Collectively, the tolerance data appear encouraging, although it should be noted that a zero event rate for a serious AE in just 10 patients is compatible with an upper 95% confidence interval of over 30%. With regard to secondary outcome measures, the data are summarized in Supplementary Table S9 online. Skin biopsies revealed no increase in C7 and no new anchoring fibrils at day 60. Fluorescence in situ hybridization analysis did not show donor-cell chimerism. Birmingham epidermolysis bullosa severity score (BEBSS) and global severity score questionnaires were completed for all the 10 participants (Supplementary Figures S2 and S3 online). Mean parent-reported pain score was lower at 60 days than at baseline (mean difference: -5.5 points; 95% confidence interval (CI): -16.3, 5.3); similar changes were seen at day 180 (mean difference -3.0 (-14.7, 8.7) (Supplementary Figure S4 online). Change in mean disease severity (total BEBSS) was -5.2 points (95% CI: -10.7, 0.3), and change in mean BEBSS total body surface area (TBSA%) was –5.9 points from baseline to day 60 (-15.3, 3.5); similar changes were seen at 180 days for both BEBSS measures (Supplementary Figure S5 online). Mean global severity score was 7.0 at baseline and 4.6 at day 60 (mean difference: -2.4 (95% CI: -3.4, -1.4). Corresponding mean change at day 180 was -1.6 (-3.0, -0.24). Mean quality of life score (higher is worse) reported by parents was 41.9 at baseline and 37.5 at day 60 (mean difference: -4.4; 95% CI: -8.1, -0.7) and 39.0 at day 180 (mean difference: -2.9; 95% CI: -7.5, 1.8) (Supplementary Figure S6 online). Qualitative data (telephone interviews at 9 months) revealed impressions for better wound healing in all the 10 subjects and for less skin redness in 9/10 with clinical benefits lasting for ~4–6 months (Figure 1 and Supplementary Figures S7 and S8 online). These data are presented in Supplementary Tables S10 and S11 online. Median blister counts at baseline, day 60, and 180 were 5.5, 3.5, and 3.5, respectively (Supplementary Figure S9 online). Mean suction blister times were limited to just two time points: 10.2 at baseline and 11.9 at day 100 (mean difference: 1.7; 95% CI: -0.5, 3.9); individual data are shown in Figure 2.Figure 2Suction blister times for each subject at baseline (day -120) and 100 days after the infusions of bone marrow–derived mesenchymal stromal cells.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Overall, the changes in efficacy outcomes were promising, although it should be remembered that this is an unblinded study of participants who are keen to help, thus giving a potential for positive information bias. Many of the subjective verbatim interviews, however, disclosed perceived benefits, such as better sleep (child and parents), a parent being able to return to work part-time because of reduced caring needs, and a family being able to plan their first vacation together and so on. Thus, although further studies of BM-MSCs in RDEB are needed to demonstrate efficacy, address mechanisms of action, and determine optimal cell dosage, our current findings indicate some benefits for daily life. Practically, MSCs can be given as a bolus over 10 minutes without sedation, and the child can resume normal activities within 1 hour. If MSCs were given in the clinic at the doses used in this trial, repeated every 6 months, we estimate that the costs would be similar to current biologics licensed to treat patients with chronic inflammatory diseases but with the potential for cost-neutrality or savings based on reduced dressing needs and shortened carer time. The Sohana Research Fund (SRF; with support from Goldman Sachs Gives) and the Dystrophic Epidermolysis Bullosa Research Association (DEBRA, UK) funded the study. The study is also supported by the UK National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust and King's College London. Supplementary material is linked to the online version of the paper at http://www.nature.com/jid