title: A Therapeutic Uricase with Reduced Immunogenicity Risk and Improved Development Properties.
abstract: Humans and higher primates are unique in that they lack uricase, the enzyme capable of oxidizing uric acid. As a consequence of this enzyme deficiency, humans have high serum uric acid levels. In some people, uric acid levels rise above the solubility limit resulting in crystallization in joints, acute inflammation in response to those crystals causes severe pain; a condition known as gout. Treatment for severe gout includes injection of non-human uricase to reduce serum uric acid levels. Krystexxa® is a hyper-PEGylated pig-baboon chimeric uricase indicated for chronic refractory gout that induces an immunogenic response in 91% of treated patients, including infusion reactions (26%) and anaphylaxis (6.5%). These properties limit its use and effectiveness. An innovative approach has been used to develop a therapeutic uricase with improved properties such as: soluble expression, neutral pH solubility, high E. coli expression level, thermal stability, and excellent activity. More than 200 diverse uricase sequences were aligned to guide protein engineering and reduce putative sequence liabilities. A single uricase lead candidate was identified, which showed low potential for immunogenicity in >200 human donor samples selected to represent diverse HLA haplotypes. Cysteines were engineered into the lead sequence for site specific PEGylation and studies demonstrated >95% PEGylation efficiency. PEGylated uricase retains enzymatic activity in vitro at neutral pH, in human serum and in vivo (rats and canines) and has an extended half-life. In canines, an 85% reduction in serum uric acid levels was observed with a single subcutaneous injection. This PEGylated, non-immunogenic uricase has the potential to provide meaningful benefits to patients with gout.
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Nyborg
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Chris
authors.initials: C
authors.lastname: Ward
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Anna
authors.initials: A
authors.lastname: Zacco
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Benoy
authors.initials: B
authors.lastname: Chacko
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Luba
authors.initials: L
authors.lastname: Grinberg
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: James C
authors.initials: JC
authors.lastname: Geoghegan
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Ryan
authors.initials: R
authors.lastname: Bean
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Michaela
authors.initials: M
authors.lastname: Wendeler
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Frank
authors.initials: F
authors.lastname: Bartnik
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Ellen
authors.initials: E
authors.lastname: O'Connor
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Flaviu
authors.initials: F
authors.lastname: Gruia
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Vidyashankara
authors.initials: V
authors.lastname: Iyer
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Hui
authors.initials: H
authors.lastname: Feng
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Varnika
authors.initials: V
authors.lastname: Roy
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Mark
authors.initials: M
authors.lastname: Berge
authors.affiliation: Ardea Biosciences, San Diego, California, United States of America.
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Miner
authors.affiliation: Ardea Biosciences, San Diego, California, United States of America.
authors.forename: David M
authors.initials: DM
authors.lastname: Wilson
authors.affiliation: Ardea Biosciences, San Diego, California, United States of America.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Zhou
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Simone
authors.initials: S
authors.lastname: Nicholson
authors.affiliation: Ardea Biosciences, San Diego, California, United States of America.
authors.forename: Clynn
authors.initials: C
authors.lastname: Wilker
authors.affiliation: MedImmune LLC, Mountain View, California, United States of America.
authors.forename: Chi Y
authors.initials: CY
authors.lastname: Wu
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Susan
authors.initials: S
authors.lastname: Wilson
authors.affiliation: MedImmune LTD, Cambridge, United Kingdom.
authors.forename: Lutz
authors.initials: L
authors.lastname: Jermutus
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Herren
authors.initials: H
authors.lastname: Wu
authors.affiliation: MedImmune LTD, Cambridge, United Kingdom.
authors.forename: David A
authors.initials: DA
authors.lastname: Owen
authors.affiliation: MedImmune LTD, Cambridge, United Kingdom.
authors.forename: Jane
authors.initials: J
authors.lastname: Osbourn
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Steven
authors.initials: S
authors.lastname: Coats
authors.affiliation: MedImmune LLC, Gaithersburg, Maryland, United States of America.
authors.forename: Manuel
authors.initials: M
authors.lastname: Baca
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D004285:Dogs; D004926:Escherichia coli / Q000378:metabolism; D006073:Gout / Q000188:drug therapy*; D006207:Half-Life; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010215:Papio; D011092:Polyethylene Glycols / Q000737:chemistry; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology / Q000493:pharmacokinetics / Q000627:therapeutic use; D013379:Substrate Specificity; D013552:Swine; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D014503:Urate Oxidase / Q000009:adverse effects / Q000276:immunology / Q000627:therapeutic use*
chemical_list: D011994:Recombinant Proteins; D011092:Polyethylene Glycols; D014503:Urate Oxidase