title: PF-03475952: a potent and neutralizing fully human anti-CD44 antibody for therapeutic applications in inflammatory diseases.
abstract: BACKGROUND
  CD44 is a cell adhesion molecule believed to play a critical role in T cell and monocyte infiltration in the inflammatory process. The reduction of CD44 expression or its ability to properly interact with its key ligand, hyaluronic acid (HA), inhibits migration and subsequent activation of cells within sites of inflammation. CD44-deficient mice exhibit decreased disease in a mouse arthritis model.
  
  
  METHODS
  Accordingly, we developed PF-03475952, a fully human IgG2 anti-CD44 monoclonal antibody (mAb).
  
  
  RESULTS
  Binding of PF-03475952 to CD44 inhibits binding of HA and induces loss of CD44 from the cell surface. PF-03475952 also passed a series of safety pharmacology assays designed to assess the risk of the mAb to bind Fc gamma receptors, stimulate cytokine release from human whole blood, and stimulate cytokine release from peripheral blood mononuclear cells (PBMC) using plate-bound antibodies. The latter assay was designed specifically to evaluate the risk of cytokine storm that had been observed with TGN1412 (immunostimulatory CD28 superagonist mAb). PF-003475952 exhibits high-affinity binding to both human and cynomolgus monkey CD44, but does not cross-react with rodent CD44. Thus, a rat anti-mouse CD44 mAb was used to demonstrate a dose-dependent decrease of disease in mouse collagen-induced arthritis. Importantly, efficacy was correlated with >50% loss of cell surface CD44 on circulating cells. Loss of CD44 expression on CD3+ lymphocytes was monitored following a single dose of PF-03475952 in cynomolgus monkeys as a pharmacodynamic marker. The recovery of CD44 expression was found to be dose-dependent. PF-03475952 doses of 1, 10, and 100 mg/kg reduced CD44 expression below 50% for 218, 373, and >504 hours, respectively.
  
  
  CONCLUSIONS
  Targeting of CD44 is a unique mechanism of action in the treatment of inflammatory diseases and is expected to reduce joint damage induced by inflammatory mediators, resulting in disease modification in inflammatory diseases such as rheumatoid arthritis.
authors.affiliation: Pfizer Global Research and Development, St. Louis Laboratories, Chesterfield, MO 63017, USA. Herbert.A.Runnels@pfizer.com
authors.forename: Herbert A
authors.initials: HA
authors.lastname: Runnels
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Weber
authors.forename: Jing
authors.initials: J
authors.lastname: Min
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Kudlacz
authors.forename: James F
authors.initials: JF
authors.lastname: Zobel
authors.forename: Carol B
authors.initials: CB
authors.lastname: Donovan
authors.forename: Mark A
authors.initials: MA
authors.lastname: Thiede
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Robbin B
authors.initials: RB
authors.lastname: Alpert
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Salafia
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Milici
authors.forename: Douglas
authors.initials: D
authors.lastname: Burdette
authors.forename: Rosonald R
authors.initials: RR
authors.lastname: Bell
authors.forename: Jean S
authors.initials: JS
authors.lastname: Beebe
authors.forename: Xu
authors.initials: X
authors.lastname: Xu
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology* / Q000627:therapeutic use; D000911:Antibodies, Monoclonal / Q000494:pharmacology* / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D057134:Antibodies, Neutralizing / Q000494:pharmacology* / Q000627:therapeutic use; D001169:Arthritis, Experimental / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism; D016207:Cytokines / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D018960:Hyaluronan Receptors / Q000276:immunology* / Q000378:metabolism; D006820:Hyaluronic Acid / Q000378:metabolism; D007074:Immunoglobulin G / Q000494:pharmacology* / Q000627:therapeutic use; D008252:Macaca fascicularis; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D015539:Platelet Activation / Q000187:drug effects; D011485:Protein Binding
chemical_list: D000893:Anti-Inflammatory Agents; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D057134:Antibodies, Neutralizing; D016207:Cytokines; D018960:Hyaluronan Receptors; D007074:Immunoglobulin G; C551479:PF-03475952; D006820:Hyaluronic Acid