RESEARCH TRIANGLE PARK, N.C. — September 9, 2026
Opus Genetics, Inc. announced positive 3- and 6-month data from the low-dose Cohort 1 of its BIRD-1 Phase 1/2 clinical trial evaluating OPGx-BEST1 in patients with BEST1-related retinal diseases, including Best vitelliform macular dystrophy (BVMD) and autosomal recessive bestrophinopathy (ARB). All five participants treated at 1.5 × 10⁹ vg/eye demonstrated clinically meaningful improvement in at least one measure of visual function, while structural improvements were observed in four participants. The company also reported a favorable safety and tolerability profile, with no serious adverse events or dose-limiting toxicities. The findings, together with recent regulatory discussions, support Opus Genetics’ plan to advance OPGx-BEST1 toward potential pivotal development, with participant dosing in a Phase 3 study expected to begin in 2027.
FDA Aligns With Potential Pivotal Microperimetry Endpoint
Opus Genetics has reached important regulatory alignment with the U.S. Food and Drug Administration following an August 2026 Type C meeting concerning the development pathway and potential endpoints for OPGx-BEST1. The company said the FDA aligned on a potential pivotal endpoint based on at least a 3-decibel improvement in microperimetry across five prespecified loci, together with a patient-reported outcome, in a randomized controlled trial. BCVA, LLVA and contrast sensitivity may also be acceptable endpoints. This regulatory interaction provides a potential framework for the design of the pivotal program and represents an important development milestone for the gene therapy. Opus Genetics also reported alignment with the FDA regarding Phase 3 and commercial manufacturing requirements, which the company expects to complete in early 2027, allowing preparations for pivotal development to proceed in parallel with ongoing clinical evaluation.
Cohort 2 Advances at Higher OPGx-BEST1 Dose
Opus Genetics has advanced OPGx-BEST1 into the higher-dose Cohort 2 at 4.5 × 10⁹ vg/eye, following the safety and proof-of-concept findings from Cohort 1. The second cohort has been over-enrolled to eight participants, compared with the originally planned five, with most participants having BVMD. Dosing is expected to be completed in Q4 2026, while topline three-month data are expected in Q2 2027. The company expects the higher-dose cohort to further characterize the safety, functional and structural effects of OPGx-BEST1 and provide information supporting the potential pivotal trial design. In Cohort 1, clinically meaningful BCVA improvements were observed in three of five participants, while three of four evaluable participants demonstrated meaningful retinal sensitivity improvements through microperimetry. Structural improvements included reductions in vitelliform material in BVMD and intraretinal fluid in ARB.
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Opus Genetics Builds Gene Therapy Path Toward 2027
The OPGx-BEST1 program is becoming a key clinical development asset within Opus Genetics’ broader inherited retinal disease gene therapy pipeline. OPGx-BEST1 uses an AAV vector to deliver a functional copy of the BEST1 gene to retinal pigment epithelial cells through single-eye subretinal administration. The company believes the Cohort 1 findings support the potential for functional and structural improvements in retinal areas where viable tissue remains, with greater functional gains observed in participants with less advanced disease. New epidemiology research cited by Opus Genetics also estimates approximately 23,600 symptomatic BEST1 patients in the United States and 45,400 globally, suggesting a larger addressable population than previously estimated. With Cohort 2 progressing, potential Phase 3 dosing planned for 2027 and a cash runway expected into 2029, Opus Genetics is positioning OPGx-BEST1 for multiple upcoming clinical and regulatory inflection points while continuing development of its broader AAV-based retinal disease pipeline.
Source: Opus Genetics, ,press release
