A pharmaceutical composition for use in the prevention and/or treatment of a neurodegenerative disorder comprising a compound comprised of one or more disaccharide units, the or each disaccharide unit comprising a uronate moiety linked to a glucosamine moiety, wherein the 2-O atom of the uronate moiety is substituted with a hydrogen atom, the 6-O atom of the glucosamine moiety is substituted with a sulphate group and the 2-N atom of the glucosamine moiety is substituted with an atom or group other than a sulphate group. The composition is particularly preferred for use in the prevention and/or treatment of Alzheimer's disease.