Timothy L. Jackson, Pravin Dugel, Robert Petrarca, Jeff Nau for the MERITAGE study group (London, UK)

Advantages:

Radiation has the potential to eliminate the proliferating endothelial cells, fibroblasts, and inflammatory cells that cause vision loss in wet age-related macular degeneration (AMD), and may therefore produce a more durable therapeutic effect than anti-VEGF therapy.

Methods:

53 subjects with classic, minimally classic, and occult AMD were enrolled. Inclusion criteria stipulated that patients were already receiving regular anti-VEGF therapy, defined as at least 3 retreatment injections in the 6 months prior to enrolment, or 5 injections in 12 months prior to enrolment.  Subjects had received a mean of 12 injections prior to enrolment.  Subjects underwent pars plana vitrectomy with targeted beta irradiation of the macula using an endoscopic probe (NeoVista, Freemont, USA) that delivered a dose of 24 Gray over 4.5 minutes. Anti-VEGF therapy was administered based on predefined retreatment criteria. Monthly OCT and fluorescein angiograms (0, 1, and 6 months) were read centrally, with monthly ETDRS visual acuity undertaken by certified examiners.

Effectiveness / Safety:

Mean ETDRS visual acuity was maintained (<1 letter loss) at 6 months. The mean number of retreatment injections was 1.9 over this period, half that in the corresponding 6 months prior to enrolment. If injections given at the time of surgery (based on pre-existing disease) were excluded, subjects received a mean of 1.2 retreatment injections.  To date there have been no unexpected safety concerns and no radiation retinopathy.