Opus Genetics Doses First Participant in OPGx-BEST1 Gene Therapy Trial for Best Disease

Opus Genetics has announced the successful dosing of the first participant in its phase 1/2 clinical trial evaluating OPGx-BEST1, the company’s investigational gene therapy for Best disease (vitelliform macular dystrophy). This milestone represents the first human administration of OPGx-BEST1 and a critical step forward in addressing a rare, vision-threatening inherited retinal disorder.

Best disease is caused by mutations in the BEST1 gene, which impair the function of the retinal pigment epithelium (RPE) and lead to progressive central vision loss, with the potential for complete blindness in severe cases. OPGx-BEST1 is designed to deliver a functional copy of the BEST1 gene through a one-time subretinal injection, aiming to restore normal RPE function.

Collaborative Effort in First Dosing Procedure

The first participant was dosed through a collaboration between Mark Pennesi, MD of the Retina Foundation of the Southwest and surgical retina specialists Kenneth Fan, MD, and Charles Wykoff, MD, of Retina Consultants of Texas.

“Dosing the first participant in our OPGx-BEST1 program is a historic moment for the Best disease community and for our team at Opus,” said George Magrath, MD, Chief Executive Officer of Opus Genetics.
“This milestone reinforces our mission to develop one-time gene therapies for inherited retinal diseases that previously had no treatment options. It’s a privilege to collaborate with leaders in the field like Drs. Pennesi, Fan, and Wykoff. We are deeply thankful to the Retina Foundation of the Southwest, Retina Consultants of Texas, and most importantly, the patients and families who place their trust in us.”

Academic and Clinical Leaders Highlight the Importance of Gene Therapy Progress

Dr. Mark Pennesi, Director of the Inherited Retinal Degeneration Clinic at the Retina Foundation of the Southwest, emphasized the collaborative nature of the achievement:

“This milestone 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. For patients with Best disease, this represents an important step toward potentially preserving and restoring vision.”

Dr. Charles Wykoff, retina specialist at Retina Consultants of Texas, added:

“The successful dosing of the first patient underscores both the potential promise of gene therapy in ophthalmology and the dedication of the entire community working to make these treatments a reality. It’s inspiring to see years of scientific progress translate into potentially meaningful advances for patients and families.”

About OPGx-BEST1 and the BIRD-1 Clinical Trial

OPGx-BEST1 is powered by Opus Genetics’ proprietary AAV-based gene therapy platform, engineered to deliver a functional BEST1 gene directly to the retinal pigment epithelium. Preclinical models demonstrated restored BEST1 expression and improved retinal function, supporting its advancement into human studies.

The ongoing BIRD-1 trial is a phase 1/2, multicenter, adaptive, open-label, dose-exploring study evaluating the safety, tolerability, and early efficacy of OPGx-BEST1 in patients diagnosed with Best Vitelliform Macular Dystrophy (BVMD) or Autosomal-Recessive Bestrophinopathy (ARB). Each participant receives a single subretinal injection in one eye, across two dosing cohorts.

Efficacy will be assessed using a range of functional and anatomical endpoints, including visual acuity and retinal imaging. Initial clinical data from the study is anticipated in the first quarter of 2026.