Concomitant therapy of epiretinal radiation, bevacizumab for neovascular AMD promising

November 12, 2007

Concomitant delivery of focal radiotherapy and bevacizumab (Avastin, Genentech) showed promise in a small multicenter feasibility study of patients with neovascular age-related macular degeneration.

Concomitant delivery of focal radiotherapy and bevacizumab (Avastin, Genentech) showed promise in a small multicenter feasibility study of patients with neovascular age-related macular degeneration (AMD), said Jeffrey S. Heier, MD, a vitreoretinal specialist in private practice in Boston. Based on these findings, a phase III pivotal trial has begun. One arm will consist of brachytherapy with ranibizumab (Lucentis, Genentech) and the other will consist of ranibizumab alone as a control.

Radiation has been considered before in the treatment of AMD, with varying degrees of success, because it has antiangiogenic, anti-inflammatory, and antifibrotic characteristics, Dr. Heier said.

In the preliminary study on which he reported, investigators in Boston, Mexico, and Brazil used a beta-particle emitter (Strontium-90, or Sr-90), in a NeoVista Epi-Rad90 Ophthalmic System. A dose of Sr-90 falls off rapidly as treatment moves away from the point source, meaning that a large dose of radiation can be delivered with less damage to the surrounding tissue, Dr. Heier said.

The study enrolled 34 treatment naïve patients with active subfoveal lesions. They were divided into two groups; one received an injection of bevacizumab 10 days before radiotherapy and a second injection 1 month after treatment. The second group received bevacizumab at the time of the radiotherapy and 1 month after. The radiation was delivered via an epiretinal approach through a vitrectomy.

Patients were followed monthly out to 12 months, with the option of re-treatment. By 12 months, when follow-up data were available on 27 of 34 patients, only five subjects had received additional therapy; four patients received one additional injection, and one patient received two.

"This means that 85% of the patients received no additional therapy," Dr. Heier said.

A rapid improvement in visual acuity occurred and was sustained over time, and patients were very unlikely to lose vision over the course of the study. In addition, at month 12, 48% of patients had gained at least three lines of vision. Foveal center thickness declined early in the study and continued to 12 months.

Safety results showed that one patient developed a retinal tear, which was easily treated. Of the 24 patients who were phakic at the time of radiation therapy, 25% progressed.