title: Delivery of G3139 using releasable PEG-linkers: impact on pharmacokinetic profile and anti-tumor efficacy.
abstract: In order to overcome the problems of enzymatic degradation and short plasma half life, which can limit the delivery of antisense oligonucleotides, and the potential immuno-stimulatory effects of CpG motifs, we utilized a polyethylene glycol (PEG) technology that employed various releasable linkers (rPEG). 5'-20 kDa-PEGylation of an anti-Bcl-2 5'-aminoalkyl-oligonucleotide with the same sequence as G3139 (Compound 1) did not alter its binding to the heparin-binding protein bFGF, nor the release of cytochrome c from isolated mitochondria treated with the conjugates. However, in 518A2 melanoma cells in vitro, PEGylation resulted in greatly diminished cellular uptake. In striking contrast, PEGylation of 1 resulted in dramatically improved pharmacokinetic profiles in vivo, with a prolonged half-life (t1/2), increased plasma concentration, and increased area under the plasma concentration-time curve (AUC). In an in vivo melanoma 518A2 xenograft mouse model, treatment with either 5'-20 kDa-PEG-1 or 1 demonstrated similar tumor growth inhibition. Furthermore, in an in vitro mouse splenocyte culture system, attachment of a PEG moiety to 1 through releasable linkers abolished the immunostimulatory response that was observed for G3139. Our results demonstrate the potential of the in vivo use of PEGylated oligonucleotides, and point out the profound differences between in vitro and in vivo models of oligonucleotide activity.
authors.affiliation: Enzon Pharmaceuticals, 20 Kingsbridge Road, Piscataway, NJ 08820, United States. hong.zhao@enzon.com <hong.zhao@enzon.com>
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.forename: Ping
authors.initials: P
authors.lastname: Peng
authors.forename: Clifford
authors.initials: C
authors.lastname: Longley
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.forename: Virna
authors.initials: V
authors.lastname: Borowski
authors.forename: Mary
authors.initials: M
authors.lastname: Mehlig
authors.forename: Prasanna
authors.initials: P
authors.lastname: Reddy
authors.forename: Jing
authors.initials: J
authors.lastname: Xia
authors.forename: Gerrit
authors.initials: G
authors.lastname: Borchard
authors.forename: Jack
authors.initials: J
authors.lastname: Lipman
authors.forename: Luba
authors.initials: L
authors.lastname: Benimetskaya
authors.forename: C A
authors.initials: CA
authors.lastname: Stein
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D045744:Cell Line, Tumor; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000493:pharmacokinetics; D016503:Drug Delivery Systems / Q000379:methods*; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008813:Mice, Inbred ICR; D008819:Mice, Nude; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013873:Thionucleotides / Q000008:administration & dosage / Q000493:pharmacokinetics*; D023041:Xenograft Model Antitumor Assays / Q000379:methods
chemical_list: D000970:Antineoplastic Agents; D003692:Delayed-Action Preparations; D013873:Thionucleotides; D011092:Polyethylene Glycols; C408162:oblimersen