title: Specifically targeting angiopoietin-2 inhibits angiogenesis, Tie2-expressing monocyte infiltration, and tumor growth.
abstract: OBJECTIVE
  Angiopoietin-1 (Ang1) plays a key role in maintaining stable vasculature, whereas in a tumor Ang2 antagonizes Ang1's function and promotes the initiation of the angiogenic switch. Specifically targeting Ang2 is a promising anticancer strategy. Here we describe the development and characterization of a new class of biotherapeutics referred to as CovX-Bodies, which are created by chemical fusion of a peptide and a carrier antibody scaffold.
  
  
  METHODS
  Various linker tethering sites on peptides were examined for their effect on CovX-Body in vitro potency and pharmacokinetics. Ang2 CovX-Bodies with low nmol/L IC(50)s and significantly improved pharmacokinetics were tested in tumor xenograft studies alone or in combination with standard of care agents. Tumor samples were analyzed for target engagement, via Ang2 protein level, CD31-positive tumor vasculature, and Tie2 expressing monocyte penetration.
  
  
  RESULTS
  Bivalent Ang2 CovX-Bodies selectively block the Ang2-Tie2 interaction (IC(50) < 1 nmol/L) with dramatically improved pharmacokinetics (T(½) > 100 hours). Using a staged Colo-205 xenograft model, significant tumor growth inhibition (TGI) was observed (40%-63%, P < 0.01). Ang2 protein levels were reduced by approximately 50% inside tumors (P < 0.01), whereas tumor microvessel density (P < 0.01) and intratumor proangiogenic Tie2(+)CD11b(+) cells (P < 0.05) were significantly reduced. When combined with sunitinib, sorafenib, bevacizumab, irinotecan, or docetaxel, Ang2 CovX-Bodies produced even greater efficacy (∼80% TGI, P < 0.01).
  
  
  CONCLUSIONS
  CovX-Bodies provide an elegant solution to overcome the pharmacokinetic-pharmacodynamic problems of peptides. Long-acting Ang2 specific CovX-Bodies will be useful as single agents and in combination with standard-of-care agents.
authors.affiliation: CovX Research, Pfizer Inc., San Diego, California 92121, USA.
authors.forename: Hanhua
authors.initials: H
authors.lastname: Huang
authors.forename: Jing-Yu
authors.initials: JY
authors.lastname: Lai
authors.forename: Janet
authors.initials: J
authors.lastname: Do
authors.forename: Dingguo
authors.initials: D
authors.lastname: Liu
authors.forename: Lingna
authors.initials: L
authors.lastname: Li
authors.forename: Joselyn
authors.initials: J
authors.lastname: Del Rosario
authors.forename: Venkata R
authors.initials: VR
authors.lastname: Doppalapudi
authors.forename: Steven
authors.initials: S
authors.lastname: Pirie-Shepherd
authors.forename: Nancy
authors.initials: N
authors.lastname: Levin
authors.forename: Curt
authors.initials: C
authors.lastname: Bradshaw
authors.forename: Gary
authors.initials: G
authors.lastname: Woodnutt
authors.forename: Rodney
authors.initials: R
authors.lastname: Lappe
authors.forename: Abhijit
authors.initials: A
authors.lastname: Bhat
mesh_terms: D020533:Angiogenesis Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D042702:Angiopoietin-2 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use; D039481:CD11b Antigen / Q000032:analysis; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression; D006801:Humans; D018796:Immunoconjugates / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D008264:Macrophages / Q000187:drug effects; D008297:Male; D051379:Mice; D009000:Monocytes; D009374:Neoplasms, Experimental / Q000188:drug therapy* / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000378:metabolism*; D010455:Peptides / Q000627:therapeutic use*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D042787:Receptor, TIE-2; D023041:Xenograft Model Antitumor Assays
chemical_list: D020533:Angiogenesis Inhibitors; D042702:Angiopoietin-2; D039481:CD11b Antigen; D018796:Immunoconjugates; D010455:Peptides; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D020794:Receptor Protein-Tyrosine Kinases; D042787:Receptor, TIE-2; C079086:Tek protein, mouse