Pentosan Polysulfate Sodium (PPS) in subjects with mucopolysaccharidosis type I (MPS I)

Mucopolysaccharidosis Type I (MPS I) is a rare inherited condition where the body cannot properly break down certain complex sugars, which then build up in cells and tissues and cause progressive damage. It affects multiple systems including the skeleton, joints, heart, and nervous system. People with MPS I commonly experience significant pain and functional limitations even after receiving standard treatments like enzyme replacement therapy (ERT) or bone marrow transplantation. This study is testing whether a drug called Pentosan Polysulfate Sodium (PPS) — already used for other conditions — can safely reduce pain and improve function in MPS I patients. Participants will receive PPS as a weekly injection (then fortnightly), and the study will run for about 73 weeks. The study is open-label, meaning everyone will know what treatment they are receiving, and up to 10 participants aged 5 and over will be enrolled. You may be eligible if you are aged 5 or older, have a confirmed MPS I diagnosis, have already received standard treatment (bone marrow transplant and/or ERT), and are able to walk independently (with or without a walking aid). People with bleeding disorders, on blood-thinning medications, or with a history of stomach ulcers would not be eligible.