Screening data from 19 patients with late-onset Pompe disease for a phase I clinical trial of AAV8 vector-mediated gene therapy.

Late-onset Pompe disease (LOPD) is a multisystem disorder with significant myopathy. The standard treatment is enzyme replacement therapy (ERT), a therapy that is lifesaving, yet with limitations. Clinical trials have emerged for other potential treatment options, including adeno-associated virus (AAV) gene therapy. We present clinical parameters and AAV antibody titers for 19 individuals with LOPD undergoing screening for a Phase I clinical trial with an AAV serotype 8 vector targeting hepatic transduction (AAV2/8-LSPhGAA). Reported clinical parameters included GAA genotype, assessments of muscle function, upright and supine spirometry, anti-recombinant human GAA antibody titers, and biomarkers. Variability in measured parameters and phenotypes of screened individuals was evident. Eligibility criteria required that all participants have six-minute walk test (6MWT) and upright forced vital capacity (FVC) below the expected range for normal individuals, and were stably treated with ERT for >2 years. All participants had Pompe disease diagnosed by enzyme deficiency, and all had the common c.-32-13T>G LOPD pathogenic variant. Screening identified 14 patients (74%) with no or minimal detectable neutralizing antibodies against AAV8 (titer ≤1:5). 6MWT distance varied significantly (percent of expected distance ranging from 24% to 91% with an average of 60 and standard deviation of 21). Upright FVC percent predicted ranged from 35% predicted to 91% predicted with an average of 66 and standard deviation of 18. None of the participants had significantly elevated alanine transaminase, which has been associated with LOPD and could complicate screening for hepatitis related to AAV gene therapy. We review the parameters considered in screening for eligibility for a clinical trial of AAV8 vector-mediated gene therapy.
Competing Interests: Dr. Dwight D. Koeberl and Dr. Priya S. Kishnani have developed the technology that is being used in the study. If the technology is commercially successful in the future, the developers and Duke University may benefit financially. Dr. Dwight D. Koeberl has served as a consultant for Sangamo Therapeutics and for Genzyme Sanofi, Amicus, and Vertex; has received grant support from Viking Therapeutics, Genzyme Sanofi, Roivant Rare Diseases, and Amicus; and has equity in Askbio, which is developing gene therapy for Pompe disease. Dr. William B. Hannah has received consulting fees from PTC Therapeutics and ReCode Therapeutics. Dr. Edward C. Smith received salary support for his role as PI on this study. Dr. Laura E. Case has received honoraria from Genzyme Sanofi and Amicus, has participated in research supported by Genzyme Sanofi, Amicus, AskBio, Valerion, Biomarin, and by Roivant Sciences; and is a member of the Pompe Registry North American Board of Advisors Genzyme Sanofi. Dr. Deeksha Bali has received research grant support and travel funds from Genzyme Sanofi, Baebies Inc., Biomarin, Alexion Inc., SOBI biopharma, and JCR biopharma. Dr. Priya S. Kishnani has received research/grant support from Sanofi Genzyme and Amicus Therapeutics. She received consulting fees and honoraria from Sanofi Genzyme, Amicus Therapeutics, Maze Therapeutics, JCR Pharmaceutical, and Asklepios Biopharmaceutical, Inc. (AskBio). She is a member of the Pompe and Gaucher Disease Registry Advisory Board for Sanofi Gezyme, Amicus Therapeutics, and Baebies. Dr. Priya S. Kishnani has equity in Asklepios Biopharmaceutical, Inc. (AskBio) which is developing gene therapy for Pompe disease and has equity in Maze Therapeutics which is developing a small molecule therapy for Pompe disease.
(© 2023 The Authors. JIMD Reports published by John Wiley & Sons Ltd on behalf of SSIEM.)