VANCOUVER, British Columbia — Patients treated under extended anti-VEGF dosing protocols for choroidal neovascularization due to age-related macular degeneration may be more likely to lose visual acuity.

John T. Thompson

"Office examinations less frequent than every 4 to 6 weeks combined with extended therapy should be used with caution, especially in eyes with good visual acuities after the induction phase," John T. Thompson, MD, said here at the American Society of Retina Specialists annual meeting.

In a retrospective analysis of 165 consecutive treatment-na?ve patients treated by Dr. Thompson at his clinic with Lucentis (ranibizumab, Genentech) or Avastin (bevacizumab, Genentech), recurrent choroidal neovascularization frequently was associated with decreased vision during extended dosing.

Dr. Thompson said that patients were treated in an induction phase (three doses every 4 to 6 weeks), followed by maintenance therapy (dosing every 4 to 6 weeks) and extended therapy (dosing less frequently than every 4 to 6 weeks). Maintenance therapy was restarted for CNV recurrence or for loss of visual acuity; thereafter, repeat extended dosing was employed.

Overall, 24 eyes lost three lines or more of vision during regular dosing, as did 38 during extended dosing. During regular dosing therapy, visual acuity loss was most frequently attributable to retinal pigment epithelium tears, recurrent pigment epithelial detachment or increased geographic atrophy. However, recurrent CNV or new hemorrhage was the causative factor in 55% of cases of visual loss during extended dosing.

"Eyes with recurrences during extended dosing were likely to have additional recurrences with repeat extended dosing," Dr. Thompson said.