title: Comparison of two doses of intravitreal bevacizumab (Avastin) for treatment of macular edema secondary to branch retinal vein occlusion: results from the Pan-American Collaborative Retina Study Group at 6 months of follow-up.
abstract: OBJECTIVE
  To report the 6-month anatomical and visual outcomes after injecting two different doses of intravitreal bevacizumab in patients with macular edema secondary to branch retinal vein occlusion (BRVO).
  
  
  METHODS
  An interventional, retrospective multicenter study of 45 eyes that were treated with at least one intravitreal injection (24 eyes, 1.25 mg; 21 eyes, 2.5 mg) of bevacizumab is reported. The main outcome measures were the central 1-mm macular thickness (CMT) and the change in ETDRS lines of best-corrected visual acuity (BCVA) at 6 months.
  
  
  RESULTS
  Forty-five eyes were injected on average 26.1 months (range, 3-86 months) after the diagnosis. The average follow-up was 35.2 weeks (range, 24-52 weeks). All patients completed at least 6 months of follow-up. In the 1.25-mg dose group, at 1 month, there was an average gain of 4.5 lines of BCVA; at 3 months, 5.1 lines of BCVA; and at 6 months, 5.1 lines of BCVA (P < 0.005). In the 2.5-mg dose group, at 1 month, there was an average gain of 2.3 lines of BCVA; at 3 months, 3.8 lines of BCVA; and at 6 months, 4.8 lines of BCVA (P = 0.05). In the 1.25-mg dose group, the mean CMT +/- SD decreased from 461 +/- 211 microm at baseline to 321 +/- 152 microm at 1 month, 273 +/- 99 microm at 3 months, and 277 +/- 114 microm at 6 months (P = 0.0002). In the 2.5-mg group, the mean CMT +/- SD decreased from 385 +/- 168 microm at baseline to 279 +/- 111 microm at 1 month, 249 +/- 97 microm at 3 months, and 240 +/- 93 microm at 6 months (P = 0.011).
  
  
  CONCLUSIONS
  There were no statistically significant differences between the two dose groups with regard to the number of injections and anatomical and functional outcomes. Intravitreal injection of bevacizumab at doses up to 2.5 mg appears to be effective in improving BCVA and reducing CMT in BRVO in the short term. Multiple injections are needed in a large number of eyes for continued control of macular edema and preservation of visual acuity in the short term. Longer studies are needed to determine what role if any intravitreal injection of bevacizumab may play in the long-term treatment of this condition.
authors.affiliation: Instituto de Cirugia Ocular, San José, Costa Rica. LW65@cornell.edu
authors.forename: Lihteh
authors.initials: L
authors.lastname: Wu
authors.forename: J Fernando
authors.initials: JF
authors.lastname: Arevalo
authors.forename: Jose A
authors.initials: JA
authors.lastname: Roca
authors.forename: Mauricio
authors.initials: M
authors.lastname: Maia
authors.forename: Maria H
authors.initials: MH
authors.lastname: Berrocal
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Rodriguez
authors.forename: Teodoro
authors.initials: T
authors.lastname: Evans
authors.forename: Rogerio A
authors.initials: RA
authors.lastname: Costa
authors.forename: Jose
authors.initials: J
authors.lastname: Cardillo
mesh_terms: D000368:Aged; D020533:Angiogenesis Inhibitors / Q000008:administration & dosage*; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab; D005260:Female; D005451:Fluorescein Angiography; D005500:Follow-Up Studies; D006801:Humans; D007267:Injections; D008269:Macular Edema / Q000188:drug therapy* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D012170:Retinal Vein Occlusion / Q000150:complications*; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence; D016896:Treatment Outcome; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors; D014792:Visual Acuity; D014822:Vitreous Body
chemical_list: D020533:Angiogenesis Inhibitors; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D042461:Vascular Endothelial Growth Factor A; D000068258:Bevacizumab