Opus Genetics reported early results from the phase 1/2 BIRD-1 trial of OPGx-BEST1, an investigational gene therapy for BEST1-related retinal diseases, including Best vitelliform macular dystrophy (BVMD) and autosomal recessive bestrophinopathy (ARB).
The first cohort included 5 participants who received 1.5×109 vector genomes (vg)/eye. Three participants with BVMD have completed 3 months of follow-up, and 2 with ARB have completed 6 months.
According to the company, all 5 participants had clinically meaningful improvement in at least 1 measure of visual function, including best-corrected visual acuity, low-luminance visual acuity, contrast sensitivity, or microperimetry. Among evaluable patients, 3 of 4 showed improvement in retinal sensitivity by microperimetry. Structural changes were observed in 4 participants, including reduced vitelliform material in 2 of 3 patients with BVMD and reduced intraretinal fluid in both patients with ARB.
No serious adverse events, dose-limiting toxicities, or intraocular inflammation were reported. Treatment-related adverse events were mild or moderate.
Opus has advanced BIRD-1 to a higher-dose cohort of 8 participants receiving 4.5×109 vg/eye. Three-month data are expected in the second quarter of 2027. The company said it expects to begin dosing a potential phase 3 trial in 2027. RP