Opus Genetics, Inc. (NASDAQ:IRD) (the "Company", "Opus Genetics" or "Opus"), a clinical-stage biopharmaceutical company developing gene therapies to restore vision and prevent blindness in patients with inherited retinal diseases (IRDs), today provided updates on its ongoing OPGx-BEST1 Phase 1/2 clinical trial (BIRD-1) targeting BEST-1 associated IRDs.

Opus expects to announce three-month topline data from Cohort 1 of the Phase 1/2 trial during the second week of September 2026, assuming all participants complete their assessments as scheduled. In addition, the Company plans to present the data at the annual EURETINA Congress taking place in Vienna, Austria from October 1 - 4, 2026.

BIRD-1 is an adaptive, open-label, Phase 1/2 study evaluating the safety and efficacy of single-eye subretinal administration of OPGx-BEST1 in adult participants with Best Vitelliform Macular Dystrophy (BVMD) or Autosomal-Recessive Bestrophinopathy (ARB). The trial is designed as a dose escalation trial to evaluate two doses of OPGx-BEST1: 1.5E9 vg/eye (Cohort 1) and 4.5E9 vg/eye (Cohort 2).

Enrollment in Cohort 1 was completed in May 2026 with five participants in the study, three with BVMD and two with ARB, who were carefully selected to meet the defined entry criteria. In the BVMD participants, the Company completed the added step of using an in vitro platform to confirm that each participant’s disease mutation is amenable to gene augmentation. After the last participant has completed the Month 3 visit, the Independent Data Monitoring Committee (IDMC) will review all Cohort 1 data and determine next steps.

In Cohort 1, the primary endpoint for evaluation is the safety and tolerability of OPGx-BEST1. In addition to safety measures, Opus will be also assessing a number of structural parameters including subretinal fluid as measured by Optical Coherence Tomography (OCT) scans. A reduction in subretinal fluid on OCT would suggest that OPGx-BEST1 has a biological effect demonstrating target engagement. A reduction trending towards 20% may be considered clinically meaningful, and these results, in addition to those on safety, are expected to be used to provide the rationale to advance the trial into Cohort 2 to optimize dose selection, per the trial protocol. Given the high level of patient interest in the trial, potential participants have already been identified to enroll in Cohort 2 if necessary. In the event that OPGx-BEST1 demonstrates a 100% reduction in fluid in the majority of patients in Cohort 1, the trial may be expanded into a potential pivotal trial. Opus expects to present the Month 3 data to the U.S. Food and Drug Administration (FDA) to align on the next steps for clinical development.

In addition to OCT structural assessments, functional endpoints will also be evaluated including microperimetry, best corrected visual acuity (BCVA), low luminance visual acuity (LLVA) and contrast sensitivity. Correlation between functional improvements and structural changes would suggest clinically meaningful target engagement by of functional improvements with structural changes would be suggestive of clinically meaningful target engagement of OPGx-BEST1.

Due to the open-label nature of the trial, the Company plans to enter an investor relations quiet period beginning July 15, 2026, and continuing until the public announcement of these data.

"We continue to work closely with our study sites and investigators to support this trial. We are deeply grateful to the participants and encouraged by the significant interest in this trial from the patient community," said George Magrath, M.D., Chief Executive Officer of Opus Genetics. "For the significant number of BEST1 patients in the U.S. and globally, there is a substantial need for treatment options, with no therapies currently available today."

Additional OPGx-BEST1 resources can be found on the Opus Genetics website:

• Overview, presentations and webcasts can be found here, including:
  • Cohort 1 Baseline Demographics and Key Endpoints for IRDs Presentation and Video Recording by Dr. Mark Pennesi (May 2026)
  • Preliminary Results from the Sentinel Participant Presentation and Video Recording by Dr. Mark Pennesi (February 2026)
• Publications and medical conference presentations can be found here, including the baseline demographics poster presentation from the Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting (May 2026).