Opus Genetics Completes Higher-Dose Cohort in Retinal Gene Therapy Trial

Key Points

• Opus Genetics completed dosing in all 11 participants in Cohort 2 of its Phase 1/2 BIRD-1 trial.
• The cohort received OPGx-BEST1 at three times the dose used in Cohort 1.
• Three-month topline results are expected in the first quarter of 2027.
• Dosing in a potential pivotal Phase 3 trial is anticipated to begin in the second half of 2027.
• Earlier findings were encouraging, but came from five participants in an open-label cohort.

Opus Genetics (NASDAQ: IRD) has completed dosing in the higher-dose cohort of OPGx-BEST1, its investigational gene therapy for BEST1-related inherited retinal diseases.

Cohort 2 enrolled 11 participants, exceeding the original target of five. Each received 4.5 billion vector genomes per eye, compared with 1.5 billion in Cohort 1. The upcoming results will help characterize safety, visual function and retinal structure at the higher dose and inform potential pivotal development.

Earlier Cohort Showed Functional and Structural Improvements

BIRD-1 is an adaptive, open-label Phase 1/2 trial evaluating a single subretinal injection in adults with Best vitelliform macular dystrophy, or BVMD, and autosomal recessive bestrophinopathy, or ARB.

In the five-participant low-dose cohort, Opus reported clinically meaningful improvement in at least one visual-function measure for every participant. Specific findings included:

• Best-corrected visual acuity improvement in three of five participants.
• Low-light visual acuity improvement in two of five.
• Contrast sensitivity improvement in two of five.
• Retinal sensitivity improvement by microperimetry in three of four evaluable participants.

Four of five participants also showed structural improvements. No serious adverse events, dose-limiting toxicities or intraocular inflammation were observed, and treatment-related adverse events were mild or moderate.

These findings provide an early signal, but the small, open-label cohort limits conclusions about efficacy and does not establish how the higher dose will perform.

Potential Phase 3 Path Includes Functional and Patient-Reported Outcomes

Opus said it reached alignment with the FDA in August 2026 on a potential pivotal endpoint combining:

• At least a three-decibel microperimetry improvement across five or more prespecified retinal locations.
• A patient-reported outcome in a randomized, controlled trial.

The company also reported alignment on Phase 3 commercial manufacturing requirements, which it expects to complete in early 2027.

That alignment supports planning but is not approval of the therapy. The potential Phase 3 trial remains a future development step.

Investor Takeaway: Two Planned Milestones in 2027

For IRD investors, the next major checkpoint is Cohort 2’s three-month readout in the first quarter of 2027, followed by the anticipated start of pivotal dosing in the second half.

OPGx-BEST1 uses an AAV vector to deliver a functional BEST1 gene to retinal pigment epithelial cells. No approved therapies currently address the underlying genetic cause of the diseases described.

The central question is whether the larger, higher-dose cohort reinforces the early safety and visual-function findings sufficiently to support controlled pivotal testing. Completing dosing advances that evaluation; it does not yet answer it.