Oral minocycline fails to slow rate of geographic atrophy enlargement in AMD
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Key takeaways:
- The difference in geographic atrophy enlargement rates was not significant between study phases.
- No significant differences were reported between phases in visual acuity and subfoveal retinal thickness.
Oral minocycline was not associated with a reduction in geographic atrophy enlargement over 24 months vs. a 9-month run-in period among patients with age-related macular degeneration, according to a study in JAMA Ophthalmology.
“We continue to look for these elusive treatments to try and slow down geographic atrophy,” Tiarnán D. L. Keenan, MD, PhD, a Stadtman Tenure-Track Investigator in the division of epidemiology and clinical applications at NIH’s National Eye Institute, told Healio.
Seeking to evaluate the safety and efficacy of oral minocycline, a tetracycline antibiotic and microglial inhibitor, in slowing geographic atrophy (GA) progression in AMD, Keenan and colleagues conducted a phase 2, prospective, single-arm trial at the National Eye Institute in Bethesda, Maryland, and Bristol Eye Hospital in the United Kingdom.
From 2016 to 2019, they enrolled 37 adults aged 55 years and older (mean age, 74.3 years; 57% women) with AMD-related GA in at least one eye. After a 9-month run-in period, participants were instructed to take oral minocycline 100 mg twice daily for 2 years, with in-clinic evaluations at months 12 and 15 and every 6 months thereafter.
“The trial design is pretty innovative,” Keenan said. “It’s not a randomized trial, so instead we had each individual acting as his or her own control.”
The primary outcome was the difference in rate of change in GA area via fundus autofluorescence between the 24-month treatment period and the run-in phase.
According to results, 21 participants (58%) completed at least 33 months of treatment. The estimated mean square root-transformed GA enlargement rate was 0.31 mm per year during run-in and 0.28 mm per year during treatment, for a non-significant difference of –0.03 mm per year. Secondary outcome measures of GA enlargement yielded similar results.
In addition, researchers reported nonsignificant differences in rate of change between phases in best-corrected visual acuity (0.2 letter score per month), low-luminance visual acuity (0.2 letter score per month) and change of subfoveal retinal thickness (0.7 m per month).
Researchers reported 49 nonocular treatment-emergent adverse events, most of which were mild, and included an increase in serum thyrotropin level and skin hyperpigmentation. Twelve serious adverse events, including one death, were reported among eight participants, although none were related to the study drug.
“The search continues for therapeutic approaches that slow geographic atrophy enlargement,” Keenan told Healio.
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