Remofuscin slows retinal thinning in Stargardt Disease (STGD1) – results from the Stargardt Remofuscin Treatment Trial (STARTT) a 2-year placebo-controlled study.

Abstract

Purpose : STGD1 causes bilateral loss of vision with no effective treatment. STARTT was designed to prospective, multicenter (6 investigator sites), randomized (2:1) clinical study to compare the efficacy and safety of daily, oral soraprazan 20mg to placebo.

Methods : Initially, the study duration was 12 months, but was later extended to 24 months. Primary endpoint was quantitative Autofluorescence (qAF); secondary endpoints included best corrected visual acuity (BCVA), retinal sensitivity measured with mesopic Microperimetry (mMP) and retinal thickness and other structural retinal features measured with Spectral Domain Optical Coherence Tomography (SD-OCT). Tests were performed monthly for the first 3 months followed by every 3 months until last visit. Eighty-seven (87) subjects (59 Remofuscin and 28 placebo) aged ≥18 years (mean age 35.5 years; 56.5% female) with genetically confirmed STGD1 before age 45, and BCVA between 49 - 83 ETDRS letters were randomised. If both eyes qualified for study entry, the eye with the higher BCVA score was defined as the study eye. Subjects were subsequently asked to continue into an extension for another year. Sixty-eight subjects (49 Remofuscin:19 placebo) agreed to the extension, with 45 Remofuscin:17 placebo (61) subjects completing. An independent reading centre (GRADE Reading Center, University of Bonn) checked subject eligibility, based on qAF >300 units, and provided assessments of qAF images, MMP outputs, and retinal and SD-OCT images.

Results : Subjects had an average of 7.3-year disease duration at baseline. There was no statistically significant difference for qAF due to unexpected variability. Preliminary results after 2 years of treatment show Remofuscin was superior to placebo for Central Subfield Retinal Thickness (study eye 6.6µm, p=0.0093 and 8.3µm, p=0079 for fellow eyes). The percent change in ellipsoid zone supported these findings with differences over placebo of 3.4% and 6.4% in the study and fellow eyes respectively.

Conclusions : Remofuscin treated subjects showed less retinal thinning on SD-OCT compared to placebo. This effect appears to increase over time and was observed in both study and fellow eyes.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.