NEW YORK — Photobiomodulation with low-level red infrared light could improve visual acuity in dry age-related macular degeneration (AMD), clinical researchers say.
The treatment, already approved in Europe and parts of Latin America, may be the first to arrest the progress of the disease, said Richard Rosen, MD, DSc (Hon), an ophthalmology professor at Icahn School of Medicine at Mount Sinai in New York City.
“It’s something to offer patients with dry AMD,” he told Medscape Medical News. “We don’t have really anything.”
Here at the American Society of Retina Specialists (ASRS) annual meeting, Rosen presented preliminary results in the LIGHTSITE III trial of the Valeda Light Delivery System being marketed by LumiThera.
The device uses multiple wavelengths of light to stimulate cells, Rosen said. The cells respond with increased energy production, altered signaling modalities, and activation of transcription factors that protect them from damage.
In LIGHTSITE III, investigators used three wavelengths. Yellow light at 590 nanometers (nm) inhibits vascular endothelial growth factor expression and removes cellular deposits, said Rosen. The red (660 nm) and infrared (850 nm) wavelengths both stimulate metabolic activity, inhibiting inflammation and cellular loss, through different effects on cytochrome c oxidase, he said.
To test the device, Rosen and colleagues enlisted 100 people with dry AMD from 10 centers around the United States and assigned 148 of their eyes to the study, with two thirds receiving treatment and one third receiving a sham treatment of doses of 590 nm and 660 nm light that the investigators considered too small to be effective.
Nearly all (99%) of the subjects were White, and 68% were women. Their average age was 75, and their average time from diagnosis was 4.9 years. Their visual acuity ranged from 20/100 to 20/32, with an average ETDRS vision chart score of 70.6 letters.
Every 4 months, the patients received nine treatments over a period of 3-4 weeks. By month 13, the mean best-corrected visual acuity in the patients treated with photobiomodulation had improved by 5.5 letters, with most of the improvement by month 4.
At month 13, the change vs baseline was statistically significant, as was the difference between the photobiomodulation group and the sham group.
A larger percentage of the patients in the photobiomodulation group gained letters and a lower percentage lost them, compared with the sham group.
Fifty-five percent of the eyes treated with photobiomodulation gained more than 5 letters, with a mean gain of 9.7 letters. Another 26.8% gained more than 10 letters, with a mean gain of 12.8 letters.
Also at month 13, the change in central drusen volume in the eyes treated with photobiomodulation was only .006 mm3, whereas in the sham-treated eyes, drusen volume increased .049 mm3. However, the increase, even in the sham-treated eyes, was not statistically significant.
New geographic atrophy occurred in only 1.1% of the eyes treated with photobiomodulation, compared with 9.1% of the sham-treated eyes, a statistically significant difference.
The results are consistent with three previous studies of the Valeda Light Delivery System, Rosen said. “They all see this sort of modest improvement in vision with stabilization of the disease, the decrease in normal drusen production, and hopefully some reduction in progression of geographic atrophy.”
In Europe, Rosen said, he has seen patients whose fixation stability improves with photobiomodulation as well.
Still, the treatment falls short of a cure, he said. “Some of the patients are high responders, and we’ll get up to maybe three and even some with four lines of improvement. But it’s a slow effect. So basically, it’s more of a maintenance kind of therapy.”
Jennifer Lim, MD, chair of ophthalmology at the University of Illinois Hospital & Health Sciences System in Chicago, who was not involved in the study, said she would like to know what physical changes could explain the improvement in visual acuity.
“I’m intrigued by it,” she told Medscape Medical News. “I want to understand it better. I think we have to find some other biomarkers that show that there is a change in anatomy that can help explain why we’re getting what we’re getting.”
The LIGHTSITE III investigators hope to complete the trial with 2 years of data later this year and submit it to the US Food and Drug Administration, Rosen said. At that time, he hopes to have more data about structural changes brought about by the treatment.
The study was funded by LumiThera. Rosen reports financial relationships with AbbVie, Boehringer Ingelheim, CellView, Guardion Health, LumiThera, Ocusciences, and Optovue. Lim reports relationships with Alcon, Aldeyra, Allergan, Aura, Chengdu Pharmaceuticals, Cognition, Eyenuk, Genentech/Roche, Graybug, Iveric Bio, Luxa, NGM, Novartis, Opthea, Quark, Regeneron, RGM, Santen, Stealth, Unity, and Veridian.
American Society of Retina Specialists. Presented July 16, 2022. ClinicalTrials.gov study record LIGHTSITE III.
Laird Harrison writes about science, health, and culture. His work has appeared in national magazines, in newspapers, on public radio, and on websites. He is at work on a novel about alternate realities in physics. Harrison teaches writing at the Writers Grotto. Visit him at www.lairdharrison.com or follow him on Twitter: @LairdH