title: Carbohydrate-mediated polyethylene glycol conjugation of TSH improves its pharmacological properties.
abstract: Thyrogen (thyrotropin alfa for injection), recombinant human TSH (rhTSH), has been successfully used to enhance diagnostic radioiodine scanning and thyroglobulin testing in the follow-up of patients with thyroid cancer and as an adjunctive treatment for radioiodine thyroid remnant ablation. However, the short half-life of rhTSH in the circulation requires a multidose regimen. We developed novel sialic acid-mediated and galactose-mediated conjugation chemistries for targeting polyethylene glycol (PEG) to the three N-linked glycosylation sites on the protein, to prolong plasma half-life by eliminating kidney filtration and potential carbohydrate-mediated clearance. Conjugates of different PEG sizes and copy numbers were screened for reaction yield, TSH receptor binding, and murine phamacokinetics/pharmacodynamics studies. The best performing of these products, a 40-kDa mono-PEGylated sialic acid-mediated conjugate, exhibited a 3.5-fold longer duration of action than rhTSH in rats, as a 5-fold lower affinity was more than compensated by a 23-fold extension of circulation half-life. Biochemical characterization confirmed conjugation through the sialic acids. Correlation of PEG distribution on the three N-linked glycosylation sites and the PEG effect on receptor binding supported the previously reported structure-function relationship of rhTSH glycosylation. This long-acting rhTSH has the potential to significantly improve patient convenience and provider flexibility while reducing potential side effects associated with a sudden elevation of serum TSH.
authors: Genzyme Corp., a Sanofi Company, Framingham, MA 01701, USA. anna.park@genzyme.com
authors: Anna
authors: A
authors: Park
authors: Denise M
authors: DM
authors: Honey
authors: Lihui
authors: L
authors: Hou
authors: Julie J
authors: JJ
authors: Bird
authors: Christine
authors: C
authors: Zarazinski
authors: Michelle
authors: M
authors: Searles
authors: Christian
authors: C
authors: Braithwaite
authors: Jonathan S
authors: JS
authors: Kingsbury
authors: Josephine
authors: J
authors: Kyazike
authors: Kerry
authors: K
authors: Culm-Merdek
authors: Ben
authors: B
authors: Greene
authors: James E
authors: JE
authors: Stefano
authors: Huawei
authors: H
authors: Qiu
authors: John M
authors: JM
authors: McPherson
authors: Clark Q
authors: CQ
authors: Pan
mesh_terms: D000818:Animals; D002241:Carbohydrates / Q000737:chemistry; D005260:Female; D006031:Glycosylation; D006207:Half-Life; D006801:Humans; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008958:Models, Molecular; D011092:Polyethylene Glycols / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D011989:Receptors, Thyrotropin / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D012794:Sialic Acids / Q000737:chemistry; D013972:Thyrotropin / Q000031:analogs & derivatives / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology*
chemical_list: D002241:Carbohydrates; D011989:Receptors, Thyrotropin; D011994:Recombinant Proteins; D012794:Sialic Acids; D011092:Polyethylene Glycols; D013972:Thyrotropin