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Single-Dose Gene-Replacement Therapy for Spinal Muscular Atrophy

Jerry R. Mendell, M.D., Samiah Al-Zaidy, M.D., Richard Shell, M.D., W. Dave Arnold, M.D., Louise R. Rodino-Klapac, Ph.D., Thomas W. Prior, Ph.D., Linda Lowes, P.T., Ph.D., Lindsay Alfano, D.P.T., Katherine Berry, P.T., Kathleen Church, M.S.W., John T. Kissel, M.D., Sukumar Nagendran, M.D., James L’Italien, Ph.D., Douglas M. Sproule, M.D., Courtney Wells, B.S., Jessica A. Cardenas, Ph.D., Marjet D. Heitzer, Ph.D., Allan Kaspar, Ph.D., Sarah Corcoran, B.S., Lyndsey Braun, B.S., Shibi Likhite, Ph.D., Carlos Miranda, Ph.D., Kathrin Meyer, Ph.D., K.D. Foust, Ph.D., Arthur H.M. Burghes, Ph.D., and Brian K. Kaspar, Ph.D.

N Engl J Med 2017; 377:1713-1722November 2, 2017DOI: 10.1056/NEJMoa1706198



Spinal muscular atrophy type 1 (SMA1) is a progressive, monogenic motor neuron disease with an onset during infancy that results in failure to achieve motor milestones and in death or the need for mechanical ventilation by 2 years of age. We studied functional replacement of the mutated gene encoding survival motor neuron 1 (SMN1) in this disease.


Fifteen patients with SMA1 received a single dose of intravenous adeno-associated virus serotype 9 carrying SMN complementary DNA encoding the missing SMN protein. Three of the patients received a low dose (6.7×1013 vg per kilogram of body weight), and 12 received a high dose (2.0×1014 vg per kilogram). The primary outcome was safety. The secondary outcome was the time until death or the need for permanent ventilatory assistance. In exploratory analyses, we compared scores on the CHOP INTEND (Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders) scale of motor function (ranging from 0 to 64, with higher scores indicating better function) in the two cohorts and motor milestones in the high-dose cohort with scores in studies of the natural history of the disease (historical cohorts).


As of the data cutoff on August 7, 2017, all 15 patients were alive and event-free at 20 months of age, as compared with a rate of survival of 8% in a historical cohort. In the high-dose cohort, a rapid increase from baseline in the score on the CHOP INTEND scale followed gene delivery, with an increase of 9.8 points at 1 month and 15.4 points at 3 months, as compared with a decline in this score in a historical cohort. Of the 12 patients who had received the high dose, 11 sat unassisted, 9 rolled over, 11 fed orally and could speak, and 2 walked independently. Elevated serum aminotransferase levels occurred in 4 patients and were attenuated by prednisolone.


In patients with SMA1, a single intravenous infusion of adeno-associated viral vector containing DNA coding for SMN resulted in longer survival, superior achievement of motor milestones, and better motor function than in historical cohorts. Further studies are necessary to confirm the safety and efficacy of this gene therapy. (Funded by AveXis and others; number, NCT02122952.)







Mol Ther. 2017 Apr 5;25(4):855-869. doi: 10.1016/j.ymthe.2017.02.013. Epub 2017 Mar 9.

Systemic AAV-Mediated β-Sarcoglycan Delivery Targeting Cardiac and Skeletal Muscle Ameliorates Histological and Functional Deficits in LGMD2E Mice.

Pozsgai ER1, Griffin DA2, Heller KN2, Mendell JR3, Rodino-Klapac LR4.


Limb-girdle muscular dystrophy type 2E (LGMD2E), resulting from mutations in β-sarcoglycan (SGCB), is a progressive dystrophy with deteriorating muscle function, respiratory failure, and cardiomyopathy in 50% or more of LGMD2E patients. SGCB knockout mice share many of the phenotypic deficiencies of LGMD2E patients. To investigate systemic SGCB gene transfer to treat skeletal and cardiac muscle deficits, we designed a self-complementary AAVrh74 vector containing a codon-optimized human SGCB transgene driven by a muscle-specific promoter. We delivered scAAV.MHCK7.hSGCB through the tail vein of SGCB-/- mice to provide a rationale for a clinical trial that would lead to clinically meaningful results. This led to 98.1% transgene expression across all muscles that was accompanied by improvements in histopathology. Serum creatine kinase (CK) levels were reduced following treatment by 85.5%. Diaphragm force production increased by 94.4%, kyphoscoliosis of the spine was significantly reduced by 48.1%, overall ambulation increased by 57%, and vertical rearing increased dramatically by 132% following treatment. Importantly, no adverse effects were seen in muscle of wild-type mice injected systemically with scAAV.hSGCB. In this well-defined model of LGMD2E, we have demonstrated the efficacy and safety of systemic scAAV.hSGCB delivery, and these findings have established a path for clinically beneficial AAV-mediated gene therapy for LGMD2E.





Gene Therapy , (20 August 2015) | doi:10.1038/gt.2015.80

β-Sarcoglycan gene transfer decreases fibrosis and restores force in LGMD2E mice

E R Pozsgai, D A Griffin, K N Heller, J R Mendell and L R Rodino-Klapac


Limb-girdle muscular dystrophy type 2E (LGMD2E) results from mutations in the β-sarcoglycan (SGCB) gene causing loss of functional protein and concomitant loss of dystrophin-associated proteins. The disease phenotype is characterized by muscle weakness and wasting, and dystrophic features including muscle fiber necrosis, inflammation and fibrosis. The Sgcb-null mouse recapitulates the clinical phenotype with significant endomysial fibrosis providing a relevant model to test whether gene replacement will be efficacious. We directly addressed this question using a codon optimized human β-sarcoglycan gene (hSGCB) driven by a muscle-specific tMCK promoter (scAAVrh74.tMCK.hSGCB). Following isolated limb delivery (5 × 1011 vector genome (vg)), 91.2% of muscle fibers in the lower limb expressed β-sarcoglycan, restoring assembly of the sarcoglycan complex and protecting the membrane from Evans blue dye leakage. Histological outcomes were significantly improved including decreased central nucleation, normalization of muscle fiber size, decreased macrophages and inflammatory mononuclear cells, and an average of a 43% reduction in collagen deposition in treated muscle compared with untreated muscle at end point. These measures correlated with improvement of tetanic force and resistance to eccentric contraction. In 6-month-old mice, as indicated by collagen staining, scAAVrh74.tMCK.hSGCB treatment reduced fibrosis by 42%. This study demonstrates the potential for gene replacement to reverse debilitating fibrosis, typical of muscular dystrophy, thereby providing compelling evidence for movement to clinical gene replacement for LGMD2E.





Gene therapy for muscular dystrophy: Lessons learned and path forward.

Mendell JRRodino-Klapac LSahenk ZMalik VKaspar BKWalker CMClark KR.

Center for Gene Therapy, Research Institute at Nationwide Children's Hospital, Department of Pediatrics, The Ohio State University, Columbus, OH 43205, United States. Electronic address:  This e-mail address is being protected from spambots. You need JavaScript enabled to view it .





A phase I trial of adeno-associated virus serotype 1–gammasarcoglycan gene therapy for limb girdle muscular dystrophy type 2C - Brain 2012; doi: 10.1093/brain/awr342, published on January 11, 2012 and available on this

Serge Herson 1, Faycal Hentati 2, Aude Rigolet 1, Anthony Behin 3, Norma B Romero 3, France Leturcq 4, Pascal Laforêt 3, Thierry Maisonobe 3, Rim Amouri 2, Hafedh Haddad 5, Muriel Audit 6, Marie Montus 5, Carole Masurier 5, Bernard Gjata 5, Christophe Georger 5, Mustapha Cheraï 7, Pierre Carlier 3, Jean-Yves Hogrel 3, Ariane Herson 3, Yves Allenbach 1, François M Lemoine 7, David Klatzmann 7, H Lee Sweeney 8, Richard C. Mulligan 9, Bruno Eymard 3, Didier Caizergues 5, Thomas Voit 3, Olivier Benveniste 1




Sustained alpha-sarcoglycan gene expression after gene transfer in limb-girdle muscular dystrophy, type 2D.

Mendell JR, Rodino-Klapac LR, Rosales XQ, Coley BD, Galloway G, Lewis S, Malik V, Shilling C, Byrne BJ, Conlon T, Campbell KJ, Bremer WG, Taylor LE, Flanigan KM, Gastier-Foster JM, Astbury C, Kota J, Sahenk Z, Walker CM, Clark KR.

Ann Neurol. 2010 Nov;68(5):629-38.


Limb-girdle muscular dystrophy type 2D gene therapy restores alpha-sarcoglycan and associated proteins.

Mendell JR, Rodino-Klapac LR, Rosales-Quintero X, Kota J, Coley BD, Galloway G, Craenen JM, Lewis S, Malik V, Shilling C, Byrne BJ, Conlon T, Campbell KJ, Bremer WG, Viollet L, Walker CM, Sahenk Z, Clark KR.

Ann Neurol. 2009 Sep;66(3):290-7.


Lack of toxicity of alpha-sarcoglycan overexpression supports clinical gene transfer trial in LGMD2D.

Rodino-Klapac LR, Lee JS, Mulligan RC, Clark KR, Mendell JR.

Neurology. 2008 Jul 22;71(4):240-7. Epub 2008 Jun 4.