Opus Genetics reports Cohort 1 data for OPGx-BEST1, aligns with FDA on pivotal endpoint
All five patients in the low-dose cohort showed visual function improvement, and Opus plans Phase 3 dosing in 2027 after an August FDA meeting.
Opus Genetics announced on September 9, 2026, positive 3- and 6-month results from the low-dose Cohort 1 of its BIRD-1 trial testing OPGx-BEST1, a gene therapy for BEST1-related retinal diseases. Cohort 1 enrolled five participants treated at 1.5 x 10⁹ vg/eye: three participants with BVMD who have reached three months of follow-up and two participants with ARB who have reached six months of follow-up.1
Following treatment, all five participants demonstrated clinically meaningful improvement in visual function, measured as one or more of BCVA, LLVA, contrast sensitivity or microperimetry, and structural improvements were observed across four participants.1 Specifically, BCVA improved in 60% of participants (3/5), LLVA improved in 40% of participants (2/5), contrast sensitivity improved in 40% of participants (2/5), and 75% (3/4) of evaluable participants showed clinically meaningful improvement in retinal sensitivity by microperimetry.1
On safety, OPGx-BEST1 demonstrated a favorable safety and tolerability profile, with no serious adverse events or dose-limiting toxicities, no intraocular inflammation and no vital-sign or safety-laboratory findings of note, with all treatment-related adverse events mild or moderate in severity.1
In August 2026, the Company met with the FDA to discuss potential endpoints for a pivotal trial and aligned on a ≥3 dB microperimetry improvement in ≥5 prespecified loci combined with a patient-reported outcome, with BCVA, LLVA and CS as possible acceptable endpoints; the companies also aligned on Phase 3 and commercial manufacturing requirements, expected to be finalized in early 2027.1 The Company currently expects to begin planning for participant dosing in the Phase 3 clinical trial in 2027.1
The higher-dose Cohort 2, evaluating OPGx-BEST1 at 4.5 x 10⁹ vg/eye, has been over-enrolled with eight participants, most with BVMD, with dosing expected complete in Q4 2026 and topline three-month data expected in Q2 2027.1 New epidemiology research estimates approximately 23,600 symptomatic BEST1 patients in the U.S. and about 45,400 globally.1
Written by readthrough’s AI from the linked primary sources and fact-checked against them automatically before publishing. Not investment advice.