LIGHTSITE II study: Photobiomodulation treatment improves vision in eyes with dry AMD

UK researchers reported that photobiomodulation (PBM) (LumiThera Inc.) therapy in patients with dry age-related macular degeneration (AMD) resulted in significant improvements in the best-corrected visual acuity (BCVA) 9 months after treatment and that retreatment at intervals of 4 months provided consistent improvements in visual function and morphologic signs of dry AMD activity and maintenance of clinical outcome benefits, according to first author Ben Burton, an honorary professor at the University of East Anglia in Norwich, England.

The LIGHTSITE II trial, designed to assess the safety and efficacy of PBM in dry AMD, is being carried out in the UK, Germany, France, Spain, and Italy.

Burton, speaking at the EURETINA 2021 Virtual Congress, explained that this technology uses wavelengths of light to target cytochrome c oxidase of the mitochondrial respiratory chain to activate energy production and improve metabolic output.

By improving cellular activities, the anatomic and clinical endpoints benefit. PBM improves cellular activities that in turn positively impact the anatomic and clinical endpoints.

The PBM treatment is delivered using a light delivery system (Valeda Light Delivery System, LumiThera Inc.), which is CE marked in the EU. A growing body of evidence, Burton noted, supports PBM in the 500- to 1000-nm wavelength spectrum as a novel treatment for dry AMD.

A total of 44 patients (53 eyes; 17 men, 27 women; mean age, 74.1 years) with dry AMD were enrolled.

However, this enrollment did not meet the original goal of 96 patients (144 eyes) because of the COVID-19 pandemic.

The study extended the positive findings of the LIGHTSITE I trial by treating earlier, intermediate dry AMD subjects with 3 rounds of PBM, Burton explained.

Patients, with vision ranging from 20/32 to 20/100 and no central geographic atrophy, were randomized to either PBM or sham using the Valeda Light Delivery System delivered 3 times weekly over 3 to 4 weeks. The light treatment is applied for 4 to 5 minutes/treatment/eye.

“PBM-treated eyes showed significant (p=0.02) improvement compared with baseline in the BCVA at 9 months in the modified intention-to-treat group (n = 51 eyes),” according to investigators. “The patients had sustained BCVA improvement at 9 months (p = 0.01) with an approximate gain of 4 letters in the PBM-treated group versus a 0.5 letter gain in the sham group (p=0.1) for patients that underwent all 27 PBM treatments (29 eyes).”

More than 33% of PBM-treated eyes gained 5 letters at 9 months. The AMD converted from dry to wet disease in 3.1% treated with PBM compared with 5.6% in the sham group and 4.8% in non-study eyes.

The investigators pointed out that that eyes at high risk for conversion to wet AMD, i.e., the fellow eye had exudative macular neovascularization, showed a 0% conversion rate after PBM treatment.

PBM treatment also was associated with no significant drusen growth at 9 months in contrast to the sham group.

A 44% decrease in growth of geographic atrophy after PBM was observed at 9 months.

No safety concerns or phototoxicity were associated with PBM.

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