Treatment combines low-dose radiation, anti-VEGF therapy for neovascular AMD

VIENNA, Austria — A new method of selective epiretinal brachytherapy combined with anti-VEGF therapy may be a promising treatment approach for patients with neovascular age-related macular degeneration.

"Radiation has been used for some time in the treatment of ocular neovascularization. It is an interesting option because it attacks several of the important components of the disease. It is antiangiogenic but also anti-inflammatory, which may have an important role in the recurrence of the disease, and also antifibrotic," Eugene de Juan, MD, said at the Euretina Congress here. "Importantly, it can work synergistically with other therapeutic approaches. Avastin (bevacizumab, Genentech) and radiation have shown synergism in colon cancer."

Studies have shown moderate effects on stabilization of vision — fairly prolonged over a couple of years but modest in terms of visual gain. From a safety standpoint, a low rate of radiation retinopathy was found, he noted.

The new retinal brachytherapy device used at the Doheny Eye Institute in Los Angeles delivers a single intraocular treatment with 24 Gy beta radiation, utilizing a strontium-90 isotope. The procedure is carried out under local anesthesia. Vitrectomy is performed, and a probe is placed into the vitreous cavity. Through this, a small radiation source is placed over the neovascular area and left in place for 3 to 4 minutes.

"The radiations are directed to the edge of the lesion, where they have a peak of power that fades toward the periphery. The exposure of surgeons and assistants to radiation is negligible," Dr. de Juan said.

Unlike other brachytherapy methods, this device has a significant impact on vision, he said.

Radiation alone resulted in visual stability in about 90% of the patients over 2 years. About 50% of the patients gained one or more letters of vision, and 17% gained more than 15 letters.

Cataract was a common complication, as is expected in procedures involving vitrectomy, and a few other small complications were reported.

"Now, roughly 200 patients have been treated, many have more than 2 years of follow-up and no case of radiation retinopathy has been reported," Dr. de Juan said.

He said he thinks this is due to the small radiation dose and to the focal character of the radiation delivered.

The brachytherapy treatment has also been found to work synergistically with anti-VEGF therapy. In a pilot study, a single radiation treatment was combined with two injections of bevacizumab. One of the injections was given immediately after the radiation procedure and the second one 30 days later.

As a result, a mean improvement of 10 letters was reported at 12 months. Seventy percent of patients improved or maintained their visual acuity, and 39% gained three or more letters.

One year after treatment, no adverse events associated with the exposure to radiation were found.

Dr. de Juan said that the advantage of this approach over anti-VEGF therapy alone is the fact that the radiation treatment is delivered only one time and the number of intravitreal injections is significantly reduced.

"This makes the treatment more cost-effective and certainly more advantageous for the patient's quality of life," he said.