Proton beam therapy combined with intravitreal anti-VEGF safe, effective for eAMD

The combination of proton beam therapy (PBT) with the intravitreal administration of anti-vascular endothelial growth factor (VEGF) reduces the need for anti-VEGF reinjection in the eyes of patients with exudative age-related macular degeneration (eAMD), a recent study has shown.

There appear to be some signals for concern, however, as geographic atrophy (GA) developed in eyes receiving high radiation doses, which could negatively impact vision in the long-term.

Twenty-three eyes of newly diagnosed patients with eAMD were entered into a phase I/II prospective, sham-controlled, double-mased investigation. Receipt of 24 GyE, 16 GyE, or sham radiation was randomly assigned at 1:1:1 ratio, and all participants were given three initial monthly doses of intravitreal ranibizumab or bevacizumab.

Over 2 years of follow-up, no significant differences in best-corrected visual acuity (BCVA) was detected between the three treatment groups, though patients who received the 24-GyE dose had worse eyesight by the end of follow-up that was of borderline significance (p=0.05).

Repeat injections of anti-VEGF was performed on case-by-case basis, and was dependent on the need as assessed by monthly optical coherence tomography. Patients who received the 24-GyE PBT dose had significantly fewer injections than their sham comparators both at the 1-year (p<0.001) and 2-year (p=0.002) follow-ups.

Those who received the 16-GyE dose also had numerically fewer repeat injections than sham patients, though the difference failed to reach significance.

In terms of treatment safety, the researchers detected no significant among-group difference in terms of mean GA area and its associated rate of growth. However, patients receiving the highest radiation dose had a nonsignificantly larger mean GA size and rate of growth as compared to the sham group. This may affect long-term vision, though further investigations are needed to determine if this is indeed related to radiation or just due to the normal progression of eAMD.