Treat-and-Extend dosing of anti-VEGF therapy for retinal angiomatous proliferation Treat and Extend is an effective dosing strategy for the treatment of patients with retinal angiomatous proliferation, according to a new study.

Since the first suggestion of a non-monthly dosing regimen in the PrONTO study, many retinal specialists have moved toward dosing individualization, with maintenance therapy provided on an as-needed basis depending upon changes seen on optical coherence tomography following an initial loading regimen. However, study data suggest that better outcomes are achieved with more treatments and closer follow up than are provided in most as-needed dosing regimens. The Treat and Extend strategy differs from as-needed strategies in that it assumes a predictable fluid-free interval. Injections are administered at this interval, and then extended to slightly longer intervals as long as there is no evidence of lesion reactivation. There is at present no consensus on optimal anti-VEGF treatment and monitoring strategies, but many clinicians prefer a variable dosing regimen over fixed monthly injections to avoid unnecessary overtreatment.

Retinal angiomatous proliferation is a distinct form of neovascularization that originates from the retina and extends posteriorly into the subretinal space, eventually communicating in some cases with new choroidal vessels. There is poor visual prognosis because of extensive exudation and progression to poor vision is common and often rapid.

This study was a retrospective analysis of visual acuity and optical coherence tomography data of 11 eyes of 10 consecutive patients with newly diagnosed retinal angiomatous proliferation treated with intravitreal Avastin (bevacizumab) and/or Lucentis (ranibizumab) with at least a 12-month follow-up. Three monthly injections were followed by continued treatment at intervals increasing by 2 weeks per visit, to a maximum of 10 weeks, unless clinical or optical coherence tomography evidence of persistent or recurrent fluid was present, in which case, the interval was shortened.

Mean baseline Snellen visual acuity was 20/80, improved to 20/40 at 1 month, and was maintained throughout the 36-month period (P < 0.04). The mean center point optical coherence tomography thickness decreased from 320 µm to 180-230 µm, and was maintained during the study period (P < 0.02). The mean number of injections was 7 in the first year, 6 in the second year, and 7 in the third year.

The investigators conclude that Treat and Extend anti-VEGF dosing in retinal angiomatous proliferation delivers promising outcomes at a reduced burden for the patient and health care system compared with monthly and as-needed dosing regimens.

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Retina. 2009 Nov-Dec;29(10):1424-31