title: Evaluation of orally administered PEGylated phenylalanine ammonia lyase in mice for the treatment of Phenylketonuria.
abstract: Phenylketonuria (PKU), a Mendelian autosomal recessive phenotype (OMIM 261600), is an inborn error of metabolism causing impaired postnatal cognitive development in the absence of treatment. We used the Pah(enu2/enu2) PKU mouse model to study oral enzyme substitution therapy with various chemically modified formulations of phenylalanine ammonia lyase (Av-p.C503S/p.C565S/p.F18A PAL). In vivo studies with the most therapeutically effective formulation (5kDa PEG-Av-p.C503S/p.C565S/p.F18A PAL) revealed that this conjugate, given orally, yielded statistically significant (p=0.0029) and therapeutically relevant reduction (~40%) in plasma phenylalanine (Phe) levels. Phe reduction occurred in a dose- and loading-dependent manner; sustained clinically and statistically significant reduction of plasma Phe levels was observed with treatment ranging between 0.3 IU and 9 IU and with more frequent and smaller dosings. Oral PAL therapy could potentially serve as an adjunct therapy, perhaps with dietary treatment, and will work independently of phenylalanine hydroxylase (PAH), correcting such forms of hyperphenylalaninemias regardless of the PAH mutations carried by the patient.
authors.affiliation: Departments of Biology, Human Genetics and Pediatrics, McGill University, and Debelle Laboratory, McGill University-Montreal Children's Hospital Research Institute, 2300 Tupper Street, A-717, Montreal, QC, H3H 1P3 Canada.
authors.forename: Christineh N
authors.initials: CN
authors.lastname: Sarkissian
authors.forename: Tse Siang
authors.initials: TS
authors.lastname: Kang
authors.forename: Alejandra
authors.initials: A
authors.lastname: Gámez
authors.forename: Charles R
authors.initials: CR
authors.lastname: Scriver
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Stevens
mesh_terms: D000284:Administration, Oral; D000464:Alginates; D046870:Anabaena variabilis / Q000201:enzymology; D000704:Analysis of Variance; D000818:Animals; D001487:Basidiomycota / Q000201:enzymology; D048271:Chitosan; D016264:Dextran Sulfate; D004305:Dose-Response Relationship, Drug; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D051379:Mice; D053758:Nanoparticles; D010649:Phenylalanine / Q000097:blood*; D010650:Phenylalanine Ammonia-Lyase / Q000008:administration & dosage / Q000235:genetics / Q000627:therapeutic use*; D010661:Phenylketonurias / Q000188:drug therapy*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D011994:Recombinant Proteins; D010649:Phenylalanine; D020723:Glucuronic Acid; D048271:Chitosan; D016264:Dextran Sulfate; D010650:Phenylalanine Ammonia-Lyase