Combined radiation, VEGF inhibitor treatment shows early efficacy against AMD

KEY BISCAYNE, Fla. — A phase 1 study found that a single treatment involving focal, direct application of radiation therapy in conjunction with bevacizumab produced impressive results against exudative age-related macular degeneration, according to a surgeon speaking here.

The phase 1 trial, which was performed outside of the United States, looked at strontium-90 brachytherapy (Epi-Rad90, NeoVista) either as monotherapy or in combination with Avastin (bevacizumab, Genentech) in an effort to find a longer-lasting treatment for choroidal neovascular AMD.

Allen C. Ho

Allen C. Ho, MD, an OSN Retina/Vitreous editorial board member, presented 1-year data from the monotherapy study and 3-month data from the combination therapy study at Bascom Palmer Eye Institute's Angiogenesis 2007 meeting. "It appears, at least, that focal epiretinal radiation may be safe for treatment of exudative AMD," Dr. Ho said.

The strontium-90 brachytherapy procedure, which takes about 30 minutes to complete, involves inserting a 20-gauge handheld device into the eye and placing it over the choroidal-neovascular complex. For combined treatments, Avastin is injected once brachytherapy is completed.

When used as monotherapy, epiretinal radiation had an "acceptable profile" for safety, with up to 25% of patients developing cataracts. Regarding efficacy, patients treated with a lower radiation dose of 15 Gy had no gains of three or more lines of vision, but 28% of those treated with a higher dose of 24 Gy had such gains, Dr. Ho said.

"At least in this preliminary study, there's a suggestion that 24 Gy might be [more] bioactive than 15 Gy as it competes with MARINA (Minimally classic/occult trial of the anti-VEGF antibody RhuFab V2 in the treatment of neovascular AMD) and ANCHOR (Anti-VEGF Antibody for the Treatment of Predominantly Classic Choroidal Neovascularization in AMD) data," Dr. Ho said.

Combining the 24 Gy dose with Avastin produced no cataracts and a low incidence of adverse events. At 3 months, 50% of the 27 patients gained three or more lines of vision, which is better than the results seen in the MARINA and ANCHOR studies, he said.

"Based on this preliminary safety data, NeoVista is launching a phase 3 prospective, controlled study of 24 Gy [brachytherapy] in combination with Lucentis (ranibizumab, Genentech/Novartis)" comparing the combination to Lucentis alone, Dr. Ho said.