Effects of gene replacement therapy with resamirigene bilparvovec (AT132) on skeletal muscle pathology in X-linked myotubular myopathy: results from a substudy of the ASPIRO open-label clinical trial

Michael W Lawlor¹, Benedikt Schoser², Marta Margeta³, Caroline A Sewry⁴, Karra A Jones⁵, Perry B Shieh⁶, Nancy L Kuntz⁷, Barbara K Smith⁸, James J Dowling⁹, Wolfgang Müller-Felber¹⁰, Carsten G Bönnemann¹¹, Andreea M Seferian¹², Astrid Blaschek¹⁰, Sarah Neuhaus¹¹, A Reghan Foley¹¹, Dimah N Saade¹¹, Etsuko Tsuchiya⁹, Ummulwara R Qasim⁶, Margaret Beatka¹³, Mariah J Prom¹³, Emily Ott¹³, Susan Danielson¹⁴, Paul Krakau¹³, Suresh N Kumar¹⁴, Hui Meng¹³, Mark Vanden Avond¹⁴, Clive Wells¹⁴, Heather Gordish-Dressman¹⁵, Alan H Beggs¹⁶, Sarah Christensen¹⁷, Edward Conner¹⁷, Emma S James¹⁷, Jun Lee¹⁷, Chanchal Sadhu¹⁷, Weston Miller¹⁷, Bryan Sepulveda¹⁷, Fatbardha Varfaj¹⁷, Suyash Prasad¹⁷, Salvador Rico¹⁷

Affiliations

¹ Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA; Diverge Translational Science Laboratory, Milwaukee, WI, 53204, USA. Electronic address: mlawlor@divergetsl.com.
² Friedrich-Baur-Institute, Department of Neurology, Ludwig Maximilian University of Munich, 80336, Germany.
³ Department of Pathology, University of California San Francisco, San Francisco, CA, 94143, USA.
⁴ Wolfson Centre of Inherited Neuromuscular Disorders, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK; Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital for Children, 30 Guilford Street, London, WC1N 1EH, UK.
⁵ Department of Pathology, Duke University School of Medicine, Durham, NC, 27710, USA.
⁶ Department of Neurology, University of California Los Angeles School of Medicine, Los Angeles, CA, 90095, USA.
⁷ Ann & Robert H Lurie Children's Hospital of Chicago, Chicago, IL, 60611, USA.
⁸ Department of Physical Therapy, University of Florida, Gainesville, FL, 32610-0154, USA.
⁹ Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada.
¹⁰ Dr. von Hauner Children's Hospital, Klinikum der Universität München, 80337, Munich, Germany.
¹¹ Neuromuscular and Neurogenetic Disorders of Childhood Section, NINDS, NIH, Bethesda, MD, 20892-1477, USA.
¹² I-Motion, Hôpital Armand Trousseau, 75571, Paris, France.
¹³ Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA; Diverge Translational Science Laboratory, Milwaukee, WI, 53204, USA.
¹⁴ Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA.
¹⁵ Children's National Hospital and George Washington University School of Medicine and Health Sciences Department of Pediatrics, Washington, DC, 20037, USA.
¹⁶ Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
¹⁷ Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA.

PMID: 38086156
PMCID: PMC10758703
DOI: 10.1016/j.ebiom.2023.104894

Effects of gene replacement therapy with resamirigene bilparvovec (AT132) on skeletal muscle pathology in X-linked myotubular myopathy: results from a substudy of the ASPIRO open-label clinical trial

Michael W Lawlor et al. EBioMedicine. 2024 Jan.

. 2024 Jan:99:104894.

doi: 10.1016/j.ebiom.2023.104894. Epub 2023 Dec 12.

Authors

Affiliations

¹ Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA; Diverge Translational Science Laboratory, Milwaukee, WI, 53204, USA. Electronic address: mlawlor@divergetsl.com.
² Friedrich-Baur-Institute, Department of Neurology, Ludwig Maximilian University of Munich, 80336, Germany.
³ Department of Pathology, University of California San Francisco, San Francisco, CA, 94143, USA.
⁴ Wolfson Centre of Inherited Neuromuscular Disorders, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK; Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital for Children, 30 Guilford Street, London, WC1N 1EH, UK.
⁵ Department of Pathology, Duke University School of Medicine, Durham, NC, 27710, USA.
⁶ Department of Neurology, University of California Los Angeles School of Medicine, Los Angeles, CA, 90095, USA.
⁷ Ann & Robert H Lurie Children's Hospital of Chicago, Chicago, IL, 60611, USA.
⁸ Department of Physical Therapy, University of Florida, Gainesville, FL, 32610-0154, USA.
⁹ Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada.
¹⁰ Dr. von Hauner Children's Hospital, Klinikum der Universität München, 80337, Munich, Germany.
¹¹ Neuromuscular and Neurogenetic Disorders of Childhood Section, NINDS, NIH, Bethesda, MD, 20892-1477, USA.
¹² I-Motion, Hôpital Armand Trousseau, 75571, Paris, France.
¹³ Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA; Diverge Translational Science Laboratory, Milwaukee, WI, 53204, USA.
¹⁴ Medical College of Wisconsin, Department of Pathology and Laboratory Medicine, Milwaukee, WI, 53226, USA.
¹⁵ Children's National Hospital and George Washington University School of Medicine and Health Sciences Department of Pediatrics, Washington, DC, 20037, USA.
¹⁶ Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
¹⁷ Formerly of Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.), San Francisco, CA, 94108, USA.

PMID: 38086156
PMCID: PMC10758703
DOI: 10.1016/j.ebiom.2023.104894

Abstract

Background: X-linked myotubular myopathy (XLMTM) is a rare, life-threatening congenital muscle disease caused by mutations in the MTM1 gene that result in profound muscle weakness, significant respiratory insufficiency, and high infant mortality. There is no approved disease-modifying therapy for XLMTM. Resamirigene bilparvovec (AT132; rAAV8-Des-hMTM1) is an investigational adeno-associated virus (AAV8)-mediated gene replacement therapy designed to deliver MTM1 to skeletal muscle cells and achieve long-term correction of XLMTM-related muscle pathology. The clinical trial ASPIRO (NCT03199469) investigating resamirigene bilparvovec in XLMTM is currently paused while the risk:benefit balance associated with this gene therapy is further investigated.

Methods: Muscle biopsies were taken before treatment and 24 and 48 weeks after treatment from ten boys with XLMTM in a clinical trial of resamirigene bilparvovec (ASPIRO; NCT03199469). Comprehensive histopathological analysis was performed.

Findings: Baseline biopsies uniformly showed findings characteristic of XLMTM, including small myofibres, increased internal or central nucleation, and central aggregates of organelles. Biopsies taken at 24 weeks post-treatment showed marked improvement of organelle localisation, without apparent increases in myofibre size in most participants. Biopsies taken at 48 weeks, however, did show statistically significant increases in myofibre size in all nine biopsies evaluated at this timepoint. Histopathological endpoints that did not demonstrate statistically significant changes with treatment included the degree of internal/central nucleation, numbers of triad structures, fibre type distributions, and numbers of satellite cells. Limited (predominantly mild) treatment-associated inflammatory changes were seen in biopsy specimens from five participants.

Interpretation: Muscle biopsies from individuals with XLMTM treated with resamirigene bilparvovec display statistically significant improvement in organelle localisation and myofibre size during a period of substantial improvements in muscle strength and respiratory function. This study identifies valuable histological endpoints for tracking treatment-related gains with resamirigene bilparvovec, as well as endpoints that did not show strong correlation with clinical improvement in this human study.

Funding: Astellas Gene Therapies (formerly Audentes Therapeutics, Inc.).

Keywords: Adeno-associated viral vector; Centronuclear myopathy; Gene replacement therapy; Human; Pathology; X-linked myotubular myopathy.

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Conflict of interest statement

Declaration of interests MWL has received research funding from Astellas Gene Therapies∗ to his academic institution (Medical College of Wisconsin) and to his company (Diverge Translational Science Laboratory) for work related to the present manuscript; has received research grants or contracts to his academic institution (Medical College of Wisconsin) from Solid Biosciences, Kate Therapeutics, Taysha Therapeutics, Ultragenyx, and Prothelia; has received consulting fees from Astellas Gene Therapies∗, Encoded Therapeutics, Modis Therapeutics, Lacerta Therapeutics, AGADA Biosciences, Dynacure, Affinia, Voyager, BioMarin, Locanabio, and Vertex Pharmaceuticals; has received speaker fees and reimbursement for travel related to sponsored research from Astellas Gene Therapies∗; has received personal fees for scientific advisory board participation for Astellas Gene Therapies∗ and Solid Biosciences, and his institution has received payment from Taysha Therapeutics for his advisory board participation; he is currently CEO, founder, and owner of Diverge Translational Science Laboratory, which continues to work under contracts from many gene therapy companies including Astellas Gene Therapies∗, Solid Biosciences, Rocket Pharma, Kate Therapeutics, Carbon Biosciences, Dynacure, Nationwide Children's Hospital, Taysha Gene Therapies, and Ultragenyx. BS (Schoser) has received grants/contracts, honoraria, and support for attending meetings from Astellas Gene Therapies∗ has participated in Advisory Boards for Dynacure. MM has received personal fees and study funding to her institution from Astellas Gene Therapies∗ in relation to the present manuscript. CAS has received royalties from Elsevier for the book “Muscle Biopsy. A Practical Approach”. KAJ has received consulting fees from Astellas Gene Therapies∗ in relation to the present manuscript and other activities. PBS has received research funding from Astellas Gene Therapies∗ to support clinical trial investigations relating to the present manuscript; has received research contracts from Biogen, Dyne, Fulcrum, Pfizer, PTC Therapeutics, Reveragen, Sanofi, Sarepta, and Solid Biosciences; has received consulting fees from Alexion, Argenx, Biogen, Novartis Gene Therapies, Pfizer, UCB, and Sarepta; has received honoraria for lectures or presentations from Alexion, Argenx, Biogen, Catalyst, CSL Behring, Genentech, and Grifols; and has participated on Independent Data Monitoring Committees for Encoded Therapeutics, Excision BioTherapeutics, and Taysha. NLK reports research grants paid to her institution from AMO Pharma, Argenx, Astellas Gene Therapies∗, Biogen, Biohaven, Novartis, NS Pharma, Sarepta, Reveragen, Roche, and Scholar Rock; has received payment for educational presentations from Sarepta; and has participated in a Data Safety Monitoring Board for Sarepta and Advisory Boards for Argenx, BioMarin, Fibrogen, Roche, and Sarepta. BKS has received institutional research grants or contracts to serve as an INCEPTUS and ASPIRO study site from Astellas Gene Therapies∗. JJD has received research grants from NIH, CIHR, and Astellas Gene Therapies∗; has received support for attending annual meetings from the World Muscle Society (as Executive Board Member) and TREAT NMD (as Chair of Executive Board); and receives annual honoraria as a Scientific Advisory Board member for the RYR1 Foundation. WMF has received support for study materials and study personnel relating to the present manuscript from Astellas Gene Therapies∗; consulting fees from Sarepta, PTC Therapeutics, Novartis, and Roche; personal compensation from Novartis and Biogen, and institutional funding from Roche, for lectures; and has served on Scientific Advisory Boards for DGM and Glykogenosis e.V. CGB reports study funding relating to the present manuscript paid to NINDS; and has participated in data safety monitoring or advisory boards without financial compensation, in his capacity of representing NIH. AMS is a principal investigator in the ASPIRO study. AB has received speaker's honoraria from Pfizer and Roche; and has participated in advisory boards at for Pfizer and Roche. SN, ARF, DNS, ET, and URQ report no conflicts of interests. MB and MJP are full-time employees of Diverge Translational Science Laboratory. EO and SD report no conflicts of interest. PK is a full-time employee of Diverge Translational Science Laboratory. SNK report no conflicts of interest. HM is a full-time employee of Diverge Translational Science Laboratory. MVA, CW, and HGD report no conflicts of interest. AHB received study funding relating to the present manuscript; reports grants or contracts received from NIH, MDA (USA), and the Chan Zuckerberg Initiative, and from AFM Telethon, Alexion Pharmaceuticals Inc., Avidity, Dynacure SAS, Kate Therapeutics, and Pfizer Inc. He has received consulting fees from Astellas Gene Therapies∗, Dynacure, GLG Inc., Guidepoint Global, Kate Therapeutics, and Roche; has received support for attending meetings from Kate Therapeutics and MDA; holds equity in Kate Therapeutics and Kinea Bio, and is an inventor on a US patent describing a method for gene therapy of XLMTM. SC, EC, JL, CS, WM, BS (Sepulveda), FV are former employees of Astellas Gene Therapies∗. ESJ and SR are former employees and stockholders in Astellas Gene Therapies∗. SP was Chief Medical Officer and a stockholder in Astellas Gene Therapies∗ when the study was designed and initiated; he is no longer a stockholder and currently consults independently with a wide variety of companies and academic institutions primarily on Clinical Development matters. ∗Formerly Audentes Therapeutics, Inc.

Figures

**Fig. 1**
**Resamirigene bilparvovec dosage level and duration of immunosuppression for the 10 participants analysed in the pathology substudy**. Muscle biopsy samples were collected at baseline (predose) and at weeks 24 and 48 following treatment with resamirigene bilparvovec gene therapy at either lower dose (1.3 × 10¹⁴ vg/kg) or higher dose (3.5 × 10¹⁴ vg/kg). ^aPrednisolone (1 mg/kg) administered for 4 weeks followed by a 4-week taper; ^bPrednisolone (1 mg/kg) administered for 8 weeks followed by an 8-week taper.

**Fig. 2**
**Biopsy findings in Group 1 participants**. H&E and NADH-TR staining of biopsies from **(a)** Participant 17, **(b)** Participant 08, and **(c)** Participant 05 are shown. Participants in this group received lower-dose resamirigene bilparvovec (1.3 × 10¹⁴ vg/kg) and a short duration of immunosuppression (1 mg/kg of prednisolone for 4 weeks followed by a 4-week taper). A normal biopsy age-matched to each participant's 48-week biopsy is shown for comparison. Also shown are participant's age at the time of biopsy, serum creatine kinase (CK), quantification of serum anti-AAV antibodies and anti-myotubularin (anti-MTM1) antibodies taken at or near the time of the biopsy, the values for myotubularin protein (MTM1 protein, % of normal skeletal muscle), *MTM1* RNA, and vector copy number that were obtained from the biopsy tissue, CHOP INTEND score, hours per day of ventilator dependence at each of these timepoints, and maximal inspiratory pressure (MIP). Scale bar = 50 μm.

**Fig. 3**
**Biopsy findings in Group 2 participants**. H&E and NADH-TR staining of biopsies from **(a)** Participant 20, **(b)** Participant 21, and **(c)** Participant 19 are shown. Participants in this group received lower-dose resamirigene bilparvovec (1.3 × 10¹⁴ vg/kg) and a long duration of immunosuppression (1 mg/kg of prednisolone for the first 8 weeks followed by an 8-week taper). A normal biopsy age-matched to each participant's 48-week biopsy is shown for comparison. Also shown are participant's age at the time of biopsy, serum creatine kinase (CK), quantification of serum anti-AAV antibodies and anti-myotubularin (anti-MTM1) antibodies taken at or near the time of the biopsy, the values for myotubularin protein (MTM1 protein, % of normal skeletal muscle), *MTM1* RNA, and vector copy number that were obtained from the biopsy tissue, CHOP INTEND score, hours per day of ventilator dependence, and maximal inspiratory pressure (MIP) at each of these timepoints. Scale bar = 50 μm.

**Fig. 4**
**Biopsy findings in Group 3 participants**. H&E and NADH-TR staining of biopsies from **(a)** Participant 25, **(b)** Participant 01, **(c)** Participant 23, and **(d)** Participant 02 are shown. Participants in this group received higher-dose resamirigene bilparvovec (3.5 × 10¹⁴ vg/kg) and a long duration of immunosuppression (1 mg/kg of prednisolone for the first 8 weeks followed by an 8-week taper). Note the 48-week biopsy for Participant 9 and the 24-week biopsy for Participant 12 are not shown because they did not contain muscle tissue. A normal biopsy age-matched to each participant's 48-week biopsy is shown for comparison. Also shown are participant's age at the time of biopsy, serum creatine kinase (CK), quantification of serum anti-AAV antibodies and anti-myotubularin (anti-MTM1) antibodies taken at or near the time of the biopsy, the values for myotubularin protein (MTM1 protein, % of normal skeletal muscle), *MTM1* RNA, and vector copy number that were obtained from the biopsy tissue, CHOP INTEND score, hours per day of ventilator dependence, and maximal inspiratory pressure (MIP) at each of these timepoints. For Participant 02, poor muscle bulk resulted in a lack of muscle tissue in the week 24 and necessitated a change in biopsy site to the triceps brachii for the week 48 biopsy. In addition, NADH-TR staining of the week 48 biopsy on Participant 02 reveals the persistence of XLMTM-type organelle mislocalisation in some fibres, in addition to a subsarcolemmal aggregation of organelles that is not observed in any other study specimens. Scale bar = 50 μm.

**Fig. 5**
**Detailed myofibre size information**. Myofibre size measurements were obtained and plotted using **(a)** frequency histogram and **(b)** cumulative probability plot methods. Due to the very large numbers of fibres sampled, all comparisons between all timepoints in a given participant demonstrated statistically significant differences at a level of p < 0.001 (nonparametric Kolmogorov–Smirnov test of distribution equality).

**Fig. 6**
**Quantification of key pathological endpoints**. **(a)** Quantification of internal nucleation (left) and organelle mislocalisation characteristic of XLMTM (right). Findings are shown for all individual participants within each group, and groups are distinguished by colour. **(b)** Individual participant data with respect to T-tubules, L-tubules, triads, and pathology score^a. ∗p < 0.05, ∗∗p < 0.01 (Wilcoxon ranked test with the significance level set at p < 0.05). Note that statistical comparisons were made between time points by evaluating all biopsies together at each time point, and statistics were not performed on separate groups. ^aXLMTM pathology score grading was assigned as follows: Grade 0, no XLMTM pathology (normal muscle or muscle with scattered atrophic fibres); Grade 1, very mild XLMTM pathology (<10% of fibres with XLMTM pathology); Grade 2, mild XLMTM pathology (11–30% of fibres with XLMTM pathology); Grade 3, moderate XLMTM pathology (31–60% of fibres with XLMTM pathology); Grade 4, moderate/severe XLMTM pathology (61–80% of fibres with XLMTM pathology); and Grade 5, severe/very severe XLMTM pathology (>81% of fibres with XLMTM pathology).

**Fig. 7**
**Evaluation of inflammation in muscle biopsies**. **(a)** CD3 staining of biopsies from study participants in which inflammation was noted at any timepoint demonstrates the relative degree of inflammation observed in individual biopsies. Any participants that are not shown did not have inflammation in any of the biopsies (Note that the 24-week biopsy for Participant 02 could not be evaluated due to lack of muscle tissue.) Scale bar = 50 μm. **(b)** Comparison of inflammatory markers in the 24-week muscle biopsies from Participants 17 and 08. Participant 17 showed the most inflammation overall in the study at this timepoint, despite low creatine kinase levels. Participant 08 showed very little inflammation while showing the highest creatine kinase in the study at this timepoint. Note that CD3 is a marker of T cells, CD4 is a marker of helper T (T_H) cells, CD8 is a marker of cytotoxic T (T_C) cells, CD20 is a marker of B cells, CD68 is a marker of macrophages, and C5b9 is a marker for the membrane attack complex of the complement cascade. Scale bar = 50 μm.

**Fig. 8**
**Summary of key structural changes following treatment with resamirigene bilparvovec**. Key elements of XLMTM pathology visible on light microscopy include small myofibre size, central aggregations of organelles, and internally placed nuclei (top). The earliest light microscopic improvement seen in all participants was restoration of appropriate organelle localization, in many cases without an impact on fibre size or nuclear placement (middle). By 48 weeks post-treatment, organelle localization remained appropriate and myofibre size had markedly increased. Nuclear placement was variable in post-treatment biopsies and in many cases did not improve with treatment.

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References

1. McEntagart M., Parsons G., Buj-Bello A., et al. Genotype-phenotype correlations in X-linked myotubular myopathy. Neuromuscul Disord. 2002;12(10):939–946. - PubMed
1. Amburgey K., Tsuchiya E., de Chastonay S., et al. A natural history study of X-linked myotubular myopathy. Neurology. 2017;89(13):1355–1364. - PMC - PubMed
1. Beggs A.H., Byrne B.J., De Chastonay S., et al. A multicenter, retrospective medical record review of X-linked myotubular myopathy: the RECENSUS study. Muscle Nerve. 2018;57(4):550–560. - PMC - PubMed
1. Annoussamy M., Lilien C., Gidaro T., et al. X-linked myotubular myopathy: a prospective international natural history study. Neurology. 2019;92(16):e1852–e1867. - PMC - PubMed
1. Graham R.J., Muntoni F., Hughes I., et al. Mortality and respiratory support in X-linked myotubular myopathy: a RECENSUS retrospective analysis. Arch Dis Child. 2020;105(4):332–338. - PMC - PubMed

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Effects of gene replacement therapy with resamirigene bilparvovec (AT132) on skeletal muscle pathology in X-linked myotubular myopathy: results from a substudy of the ASPIRO open-label clinical trial

Affiliations

Effects of gene replacement therapy with resamirigene bilparvovec (AT132) on skeletal muscle pathology in X-linked myotubular myopathy: results from a substudy of the ASPIRO open-label clinical trial

Authors

Affiliations

Abstract

Conflict of interest statement

Figures

References

MeSH terms

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