title: Switching therapy from bevacizumab to aflibercept for the management of persistent diabetic macular edema.
abstract: OBJECTIVE
  To evaluate the visual and anatomical outcomes following switching therapy from bevacizumab to aflibercept in patients with persistent diabetic macular edema (DME).
  
  
  METHODS
  Patients with DME and central macular thickness (CMT) >300 μm on spectral domain optical coherence tomography (SD-OCT) despite at least 4 intravitreal bevacizumab injections in the prior 6 months were recruited for this prospective, single-armed, single centre, open-label clinical trial. Five loading doses of intravitreal aflibercept were administered every 4 weeks until week 16, at which point the treatment interval was extended to 8 weeks. All participants were reviewed every 4 weeks. At each visit, examination included best-corrected visual acuity (BCVA) measured with an Early Treatment of Diabetic Retinopathy Study chart and CMT measured with SD-OCT. Primary outcome measures were change in CMT and BCVA at week 24 compared with baseline.
  
  
  RESULTS
  A total of 43 eyes from 43 patients were recruited for the study. At enrolment, study eyes had a mean ± standard deviation of 16.6 ± 11.5 previous intravitreal anti-VEGF injections over a period of 26.9 ± 23.8 months. Mean CMT reduced from 417 ± 91 μm at baseline to 380 ± 102 μm at 24 weeks (mean reduction 37 μm, p < 0.01). Mean BCVA improved from 67.8 ± 10.3 letters at baseline to 71.0 ± 10.1 letters at 24 weeks (mean 3.2 letter gain, p < 0.01). Eyes improving by ≥5 letters at 4 weeks following the first injection had improved vision outcomes at 24 weeks (6.8 ± 7.1 letters vs. 1.0 ± 4.7 letters, p < 0.01).
  
  
  CONCLUSIONS
  Intravitreal aflibercept was effective in improving anatomical and visual outcomes among patients with incomplete response to intravitreal bevacizumab with 24 weeks of follow up.
  
  
  BACKGROUND
  ACTRN12614001307695.
authors.affiliation: Sydney Institute of Vision Science, 13/187 Macquarie Street, Sydney, New South Wales, 2000, Australia.|Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Bobak
authors.initials: B
authors.lastname: Bahrami
authors.affiliation: Sydney Institute of Vision Science, 13/187 Macquarie Street, Sydney, New South Wales, 2000, Australia.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hong
authors.affiliation: Sydney Institute of Vision Science, 13/187 Macquarie Street, Sydney, New South Wales, 2000, Australia.
authors.forename: Meidong
authors.initials: M
authors.lastname: Zhu
authors.affiliation: Sydney School of Public Health, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Schlub
authors.affiliation: Sydney Institute of Vision Science, 13/187 Macquarie Street, Sydney, New South Wales, 2000, Australia. achang@sydneyretina.com.au.|Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia. achang@sydneyretina.com.au.
authors.forename: Andrew
authors.initials: A
authors.lastname: Chang
mesh_terms: D020533:Angiogenesis Inhibitors / Q000008:administration & dosage; D000068258:Bevacizumab / Q000008:administration & dosage*; D003930:Diabetic Retinopathy / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D004305:Dose-Response Relationship, Drug; D005260:Female; D005451:Fluorescein Angiography; D005500:Follow-Up Studies; D005654:Fundus Oculi; D006801:Humans; D058449:Intravitreal Injections; D008269:Macular Edema / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D040262:Receptors, Vascular Endothelial Growth Factor / Q000008:administration & dosage*; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage*; D013997:Time Factors; D041623:Tomography, Optical Coherence; D016896:Treatment Outcome; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors; D014792:Visual Acuity
chemical_list: D020533:Angiogenesis Inhibitors; D011993:Recombinant Fusion Proteins; D042461:Vascular Endothelial Growth Factor A; C533178:aflibercept; D000068258:Bevacizumab; D040262:Receptors, Vascular Endothelial Growth Factor
keywords: Aflibercept; Anti-vascular endothelial growth factor; Bevacizumab; Diabetic macular edema; Switch; Treatment resistant