Liver-Directed Adeno-Associated Virus-Mediated Gene Therapy for Mucopolysaccharidosis Type VI.

BACKGROUND: Mucopolysaccharidosis type VI (MPS VI) is an inherited multisystem lysosomal disorder due to arylsulfatase B (ARSB) deficiency that leads to widespread accumulation of glycosaminoglycans (GAG), which are excreted in increased amounts in urine. MPS VI is characterized by progressive dysostosis multiplex, connective tissue and cardiac involvement, and hepatosplenomegaly. Enzyme replacement therapy (ERT) is available but requires life-long and costly intravenous infusions; moreover, it has limited efficacy on diseased skeleton and cardiac valves, compromised pulmonary function, and corneal opacities. METHODS: We enrolled nine patients with MPS VI 4 years of age or older in a phase 1/2 open-label gene therapy study. After ERT was interrupted, patients each received a single intravenous infusion of an adeno-associated viral vector serotype 8 expressing ARSB. Participants were sequentially enrolled in one of three dose cohorts: low (three patients), intermediate (two patients), or high (four patients). The primary outcome was safety; biochemical and clinical end points were secondary outcomes. RESULTS: The infusions occurred without severe adverse events attributable to the vector, meeting the prespecified end point. Participants in the low and intermediate dose cohorts displayed stable serum ARSB of approximately 20% of the mean healthy value but returned to ERT by 14 months after gene therapy because of increased urinary GAG. Participants in the high-dose cohort had sustained serum ARSB of 30% to 100% of the mean healthy value and a modest urinary GAG increase that did not reach a concentration at which ERT reintroduction was needed. In the high-dose group, there was no clinical deterioration for up to 2 years after gene therapy. CONCLUSIONS: Liver-directed gene therapy for participants with MPS VI did not have a dose-limiting side-effect and adverse event profile; high-dose treatment resulted in ARSB expression over at least 24 months with preliminary evidence of disease stabilization. (Funded by the Telethon Foundation ETS, the European Commission Seventh Framework Programme, and the Isaac Foundation; ClinicalTrials.gov number, NCT03173521; EudraCT number, 2016-002328-10.)

Understanding the Early Presentation of Mucopolysaccharidoses Disorders: Results of a Systematic Literature Review and Physician Survey

Abstract As therapies are developed for rare disorders, challenges of early diagnosis become particularly relevant. This article focuses on clinical recognition of mucopolysaccharidoses (MPS), a group of rare genetic diseases related to abnormalities in lysosomal function. As quality of outcomes with current therapies is impacted by timing of intervention, minimizing time to diagnosis is critical. The objective of this study was to characterize how, when, and to whom patients with MPS first present and develop tools to stimulate earlier recognition of MPS. A tripartite approach was used, including a systematic literature review yielding 194 studies, an online physician survey completed by 209 physicians who described

Impact of Elosulfase Alfa on Pain in Patients with Morquio A Syndrome over 52 Weeks: MOR-008: A Randomized, Double-Blind, Pilot Study

Abstract Patients with mucopolysaccharidosis (MPS), and Morquio A syndrome (MPS IVA) in particular, often report substantial pain burden. MOR-008 was a randomized, double-blind, pilot study assessing the safety and efficacy, including impact on patient-reported pain, of 52 weeks of treatment with elosulfase alfa (at a dose of 2.0 or 4.0 mg/kg/week) in patients with Morquio A syndrome (?7 years old). Assessment of pain at baseline revealed that patients (N = 25) had a mean number of pain locations of 5.7, mean pain intensity score of 4.6 (indicative of medium pain), and a mean number of selected pain descriptors of 7.4 words. Treatment with elosulfase alfa improved subjective pain score (reduced to 3.2), pain locations (reduced by a mean of 1 location), and pain descriptor words (reduced to 4.9 words) over 1 year (52 weeks), suggesting that elosulfase alfa can reduce pain in some patients with Morquio A.

Expert Opinions on Managing Fertility and Pregnancy in Patients With Mucopolysaccharidosis

Abstract The mucopolysaccharidosis (MPS) disorders are rare genetic diseases caused by deficiencies in lysosomal enzymes involved in the degradation of glycosaminoglycans, leading to pulmonary, cardiac and neurological dysfunctions, skeletal anomalies, impaired vision, and/or hearing and shortened life spans. Whereas in the past, few individuals with MPS reached adulthood, better diagnosis, multidisciplinary care, and new therapies have led to an increasing number of adult patients with MPS. Therefore, fertility and pregnancy questions in this patient population are becoming more important. Management of fertility issues and pregnancy in patients with MPS is challenging due to the lack of documented cases and a dearth in the literature on this topic. This review presents multidisciplinary expert opinions on managing fertility and pregnancy based on case studies and clinical experience presented at a meeting of MPS specialists held in Berlin, Germany, in April 2015. An overview of the existing literature on this subject is also included.