title: Aqueous vascular endothelial growth factor and ranibizumab concentrations after monthly and bimonthly intravitreal injections of ranibizumab for age-related macular degeneration.
abstract: OBJECTIVE
  To evaluate vascular endothelial growth factor (VEGF) and ranibizumab concentrations in eyes with age-related macular degeneration (AMD) after monthly and bimonthly intravitreal ranibizumab (IVR) injections.
  
  
  METHODS
  Aqueous humor samples were obtained from 26 eyes with AMD before and after IVR injections. Nine eyes received three monthly injections and 17 eyes received two bimonthly injections. The VEGF and ranibizumab concentrations were measured by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  The aqueous VEGF concentrations in the monthly injection group decreased below the lowest detectable limit in eight of nine eyes 1 month after the first injection and seven of nine eyes 1 month after the second injection (P < 0.001, mean baseline value, 94.7 pg/ml); the aqueous VEGF concentrations in the bimonthly injection group decreased below the lowest detectable limit in two of 17 eyes 2 months after the first injection (P < 0.001, mean baseline value, 152.4 pg/ml). The mean aqueous ranibizumab concentrations with monthly injections were 71.2 ng/ml 1 month after the first injection, and 96.3 ng/ml 1 month after the second injection. The mean aqueous ranibizumab concentrations in the bimonthly injection group were 2.5 ng/ml in 15 of 17 eyes, and below the lowest detectable limit in two of 17 eyes 2 months after the first injection.
  
  
  CONCLUSIONS
  In this pilot study with limited follow-up, intravitreal injection of ranibizumab can suppress aqueous VEGF completely for 1 month in most cases. Its effect does not last for 2 months enough to suppress VEGF completely in most cases, although aqueous VEGF at 2 months after intravitreal injection of ranibizumab is less than that before injection in most cases.
authors.affiliation: Department of Ophthalmology, Shiga University of Medical Science, Seta Tukinowacho, Otsu, Shiga, 520-2192, Japan.
authors.forename: Xiying
authors.initials: X
authors.lastname: Wang
authors.forename: Tomoko
authors.initials: T
authors.lastname: Sawada
authors.forename: Masashi
authors.initials: M
authors.lastname: Kakinoki
authors.forename: Taichiro
authors.initials: T
authors.lastname: Miyake
authors.forename: Hajime
authors.initials: H
authors.lastname: Kawamura
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Saishin
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.forename: Masahito
authors.initials: M
authors.lastname: Ohji
mesh_terms: D000368:Aged; D020533:Angiogenesis Inhibitors / Q000008:administration & dosage / Q000493:pharmacokinetics*; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001082:Aqueous Humor / Q000378:metabolism*; D001682:Biological Availability; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D058449:Intravitreal Injections; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D000069579:Ranibizumab; D014018:Tissue Distribution; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014792:Visual Acuity / Q000502:physiology; D057135:Wet Macular Degeneration / Q000188:drug therapy / Q000378:metabolism*
chemical_list: D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D000069579:Ranibizumab