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Hart CC, Lee YI, Xie J, Gao G, Lin BL, Hammers DW, Sweeney HL. Potential limitations of microdystrophin gene therapy for Duchenne muscular dystrophy. JCI Insight 2024; 9:e165869. [PMID: 38713520 DOI: 10.1172/jci.insight.165869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 05/01/2024] [Indexed: 05/09/2024] Open
Abstract
Clinical trials delivering high doses of adeno-associated viruses (AAVs) expressing truncated dystrophin molecules (microdystrophins) are underway for Duchenne muscular dystrophy (DMD). We examined the efficiency and efficacy of this strategy with 4 microdystrophin constructs (3 in clinical trials and a variant of the largest clinical construct), in a severe mouse model of DMD, using AAV doses comparable with those in clinical trials. We achieved high levels of microdystrophin expression in striated muscles with cardiac expression approximately 10-fold higher than that observed in skeletal muscle. Significant, albeit incomplete, correction of skeletal muscle disease was observed. Surprisingly, a lethal acceleration of cardiac disease occurred with 2 of the microdystrophins. The detrimental cardiac effect appears to be caused by variable competition (dependent on microdystrophin design and expression level) between microdystrophin and utrophin at the cardiomyocyte membrane. There may also be a contribution from an overloading of protein degradation. The significance of these observations for patients currently being treated with AAV-microdystrophin therapies is unclear since the levels of expression being achieved in the DMD hearts are unknown. However, these findings suggest that microdystrophin treatments need to avoid excessively high levels of expression in the heart and that cardiac function should be carefully monitored in these patients.
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Affiliation(s)
- Cora C Hart
- Department of Pharmacology & Therapeutics and
- Myology Institute, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Young Il Lee
- Department of Pharmacology & Therapeutics and
- Myology Institute, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Jun Xie
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worchester, Massachusetts, USA
| | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worchester, Massachusetts, USA
| | - Brian L Lin
- Department of Cell Biology, Neurobiology, and Anatomy & Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - David W Hammers
- Department of Pharmacology & Therapeutics and
- Myology Institute, University of Florida College of Medicine, Gainesville, Florida, USA
| | - H Lee Sweeney
- Department of Pharmacology & Therapeutics and
- Myology Institute, University of Florida College of Medicine, Gainesville, Florida, USA
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Zaidman CM, Proud CM, McDonald CM, Lehman KJ, Goedeker NL, Mason S, Murphy AP, Guridi M, Wang S, Reid C, Darton E, Wandel C, Lewis S, Malhotra J, Griffin DA, Potter RA, Rodino-Klapac LR, Mendell JR. Delandistrogene Moxeparvovec Gene Therapy in Ambulatory Patients (Aged ≥4 to <8 Years) with Duchenne Muscular Dystrophy: 1-Year Interim Results from Study SRP-9001-103 (ENDEAVOR). Ann Neurol 2023; 94:955-968. [PMID: 37539981 DOI: 10.1002/ana.26755] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/05/2023]
Abstract
OBJECTIVE Delandistrogene moxeparvovec is approved in the USA for the treatment of ambulatory patients (4-5 years) with Duchenne muscular dystrophy. ENDEAVOR (SRP-9001-103; NCT04626674) is a single-arm, open-label study to evaluate delandistrogene moxeparvovec micro-dystrophin expression, safety, and functional outcomes following administration of commercial process delandistrogene moxeparvovec. METHODS In cohort 1 of ENDEAVOR (N = 20), eligible ambulatory males, aged ≥4 to <8 years, received a single intravenous infusion of delandistrogene moxeparvovec (1.33 × 1014 vg/kg). The primary endpoint was change from baseline (CFBL) to week 12 in delandistrogene moxeparvovec micro-dystrophin by western blot. Additional endpoints evaluated included: safety; vector genome copies; CFBL to week 12 in muscle fiber-localized micro-dystrophin by immunofluorescence; and functional assessments, including North Star Ambulatory Assessment, with comparison with a propensity score-weighted external natural history control. RESULTS The 1-year safety profile of commercial process delandistrogene moxeparvovec in ENDEAVOR was consistent with safety data reported in other delandistrogene moxeparvovec trials (NCT03375164 and NCT03769116). Delandistrogene moxeparvovec micro-dystrophin expression was robust, with sarcolemmal localization at week 12; mean (SD) CFBL in western blot, 54.2% (42.6); p < 0.0001. At 1 year, patients demonstrated stabilized or improved North Star Ambulatory Assessment total scores; mean (SD) CFBL, +4.0 (3.5). Treatment versus a propensity score-weighted external natural history control demonstrated a statistically significant difference in least squares mean (standard error) CFBL in North Star Ambulatory Assessment, +3.2 (0.6) points; p < 0.0001. INTERPRETATION Results confirm efficient transduction of muscle by delandistrogene moxeparvovec. One-year post-treatment, delandistrogene moxeparvovec was well tolerated, and demonstrated stabilized or improved motor function, suggesting a clinical benefit for patients with Duchenne muscular dystrophy. ANN NEUROL 2023;94:955-968.
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Affiliation(s)
- Craig M Zaidman
- Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
| | - Crystal M Proud
- Children's Hospital of the King's Daughters, Norfolk, VA, USA
| | | | - Kelly J Lehman
- Center for Gene Therapy, Nationwide Children's Hospital, Columbus, OH, USA
| | - Natalie L Goedeker
- Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
| | | | | | | | | | - Carol Reid
- Roche Products Ltd, Welwyn Garden City, UK
| | | | | | - Sarah Lewis
- Sarepta Therapeutics, Inc., Cambridge, MA, USA
| | | | | | | | | | - Jerry R Mendell
- Center for Gene Therapy, Nationwide Children's Hospital, Columbus, OH, USA
- The Ohio State University, Columbus, OH, USA
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Potter RA, Griffin DA, Heller KN, Mendell JR, Rodino-Klapac LR. Expression and function of four AAV-based constructs for dystrophin restoration in the mdx mouse model of Duchenne muscular dystrophy. Biol Open 2023; 12:bio059797. [PMID: 37670674 PMCID: PMC10538294 DOI: 10.1242/bio.059797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 08/22/2023] [Indexed: 09/07/2023] Open
Abstract
Robust expression of shortened, functional dystrophin provided impetus to develop adeno-associated virus (AAV)-based constructs for clinical application. Because several cassettes are being tested in clinical trials, this study compared the efficacies of four shortened dystrophin-promoter combinations with implications for outcomes in clinical trials: MHCK7 or MCK promoter with a shortened dystrophin transgene containing the N-terminus and spectrin repeats R1, R2, R3 and R24 (rAAVrh74.MHCK7.micro-dystrophin and rAAVrh74.MCK.micro-dystrophin, respectively); shortened dystrophin construct containing the neuronal nitric oxide (nNOS) binding site (rAAVrh74.MHCK7.DV.mini-dystrophin); and shortened dystrophin containing the C-terminus (rAAVrh74.MHCK7.micro-dystrophin.Cterm). Functional and histological benefit were examined at 4 weeks following intramuscular delivery in mdx mice. rAAVrh74.MHCK7.micro-dystrophin provided the most robust transgene expression and significantly increased specific force output in the tibialis anterior muscle. Muscle environment was normalized (i.e. reductions in central nucleation), indicating functional and histological advantages of rAAVrh74.MHCK7.micro-dystrophin. Thus, promoter choice and transgene design are critical for optimal dystrophin expression/distribution for maximal functional improvement.
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Affiliation(s)
- Rachael A. Potter
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
- Sarepta Therapeutics, Inc., Cambridge, MA 02142, USA
| | - Danielle A. Griffin
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
- Sarepta Therapeutics, Inc., Cambridge, MA 02142, USA
| | - Kristin N. Heller
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Jerry R. Mendell
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
- Department of Pediatrics and Neurology, The Ohio State University, Columbus, OH 43210, USA
| | - Louise R. Rodino-Klapac
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
- Sarepta Therapeutics, Inc., Cambridge, MA 02142, USA
- Department of Pediatrics and Neurology, The Ohio State University, Columbus, OH 43210, USA
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