Emixustat not beneficial in managing geographic atrophy in AMD
Treatment with emixustat does not appear to help reduce the growth rate of geographic atrophy in patients with age-related macular degeneration (AMD), according to the results of a phase IIb/III trial.
The trial randomized 503 patients with geographic atrophy secondary to AMD to treatment with emixustat 2.5 mg (n=133), 5 mg (n=134), 10 mg (n=103) or placebo (n=133), administered orally once daily for 24 months. Visual acuity score at baseline was ≥35 letters, while the total area of geographic atrophy was 1.25–18 mm2.
At 24 months, the primary endpoint of mean annual growth rate of total geographic atrophy area in the study eye, as measured using a central reading centre using fundus autofluorescence (FAF) images, did not significantly differ across the treatment groups (1.69–1.84 mm2/year with emixustat vs 1.69 mm2/year with placebo; p≥0.81).
Likewise, comparable results were obtained for the secondary efficacy endpoint of change from baseline in normal luminance best-corrected visual acuity. Of note, patients with a larger low luminance deficit (LLD) at baseline (≥20 letters) showed a more rapid growth of geographic atrophy over 24 months.
Growth rate of geographic atrophy was not associated with the risk-allele status of the AMD-associated single-nucleotide polymorphisms tested.
Commonly reported adverse events in emixustat-treated subjects were delayed dark adaptation (55 percent), chromatopsia (18 percent), visual impairment (15 percent) and erythropsia (15 percent).
The present data do not support modulation of the visual cycle by emixustat as an efficacious treatment strategy for geographic atrophy secondary to AMD, researchers said.
Additionally, the study confirms the natural history of geographic atrophy growth rate in a large population, as well as validates the association of this growth rate with baseline measures of geographic atrophy area, multifocal lesions, foveal atrophy, reticular pseudodrusen and LLD, researchers noted.