Dry AMD treatment fails in 24-month trial

Emixustat hydrochloride, a small molecule that showed promise for treating dry age-related macular degeneration (AMD) in an early phase 2 study, failed to reach its primary endpoint of slowing progression of geographic atrophy (GA) associated with AMD in a 24-month phase 2b/3 clinical trial, Frank G Holz MD, Bonn, Germany, told the 16th EURETINA Congress in Copenhagen yesterday. GA lesion growth rates in the three treatment arms of 2.5mg, 5.0mg and 10mg oral emixustat did not differ significantly from placebo at any point in the 24-month follow-up period, Dr Holz reported on behalf of the USA-based SEATTLE Study Group. Changes in best corrected visual acuity were small and similar across the four groups throughout the prospective, randomised, placebo-controlled study involving 508 patients. The most common adverse events were ocular, including delayed dark adaptation and chromatopsia. These likely were related to emixustat’s mechanism of action which inhibits retinal pigment epithelium protein 65 (RPE65), a key rate-limiting enzyme in the visual cycle, Dr Holz said. Dropout rates in the treatment arms were double the placebo arm, driven largely by ocular problems. No significant non-ocular safety issues were reported. “The SEATTLE Study adds to the understanding of the natural history of GA,” Dr Holz said. The study sponsor – Acucela, Tokyo, Japan – plans to evaluate emixustat in the treatment of Stargardt disease in the near future, he added.