The first participant has been dosed in Opus Genetics OPGx-BEST1 Phase 1/2 clinical trial for Best disease (BEST1).1
Best disease, or vitelliform macular dystrophy, is a rare, inherited retinal condition causing macular degeneration by mutations in the BEST1 gene, leading to progressive vision loss and, in some cases, blindness.
OPGx-BEST1 leverages Opus Genetics’ proprietary AAV-based gene therapy platform, designed to deliver a functional copy of the BEST1 gene directly to the retinal pigment epithelium (RPE) cells where the defective gene resides. The program builds on extensive preclinical work demonstrating restoration of BEST1 protein expression and improved retinal function in relevant disease models.
For patients with Best disease, this represents an important step toward potentially preserving and restoring vision.
The multi-centre, adaptive, open-label, dose-exploring study, known as BIRD-1, will evaluate the safety, tolerability, and preliminary efficacy of OPGx-BEST1 in participants with Best vitelliform macular dystrophy (BVMD) or autosomal-recessive bestrophinopathy (ARB). Treatment will be administered via a single subretinal injection in one eye of each participant with two dosing cohorts. The trial will also explore biological activity through functional and anatomical endpoints, including changes in visual function and retinal structure. Initial data from the trial is expected in the first quarter of 2026.
The Phase 1/2 trial is being conducted by Dr Mark Pennesi of the Retina Foundation of the Southwest and the surgical team of Drs Kenneth Fan and Charles Wykoff at Retina Consultants of Texas.
Dr Pennesi described dosing the first participant was a “milestone” that “highlights the significant progress being made in ophthalmic gene therapy and the potential power of collaboration between industry and academia to bring new hope to families affected by inherited retinal diseases”.
Reference
- Available at: ir.opusgtx.com/press-releases/detail/509/opus-genetics-announces-dosing-of-first-participant-in-opgx-best1-phase-12-gene-therapy-clinical-trial-for-best-disease [accessed 18 Nov 2025].
“For patients with Best disease, this represents an important step toward potentially preserving and restoring vision.”
