RG6501 phase 1/2a results show evidence of improvement of outer retinal structure in patients with GA

(Image Credit: AdobeStock/Lucky Ai)

Lineage Cell Therapeutics Inc. announced the results of imaging analyses demonstrating rapid improvement in outer retinal structure from patients enrolled in a Phase 1/2a clinical study of RG6501 (OpRegen; NCT02286089).

In a presentation Thursday at the 2023 EURETINA Congress titled “Time to retinal structure improvements following OpRegen subretinal delivery in patients with geographic atrophy (GA),” Adiel Barak, MD, professor of Ophthalmology and Vitreoretinal Unit Director, Tel Aviv Medical Center, offered details of the clinical trial on behalf of Roche and Genentech, a member of the Roche Group.

According to the company, RG6501 is a suspension of human allogeneic retinal pigmented epithelial (RPE) cells currently in development for the treatment of GA secondary to age-related macular degeneration (AMD).

Moreover, the company noted in its news release RG6501 subretinal delivery could counteract RPE cell loss in areas of GA lesions by supporting retinal cell health and improving retinal structure and function.

RG6501 is being developed as part of a global collaboration between Lineage, Roche and Genentech and is being examined as part of a Phase 2a clinical review (NCT 05626114) in patients with GA secondary to AMD. It is still enrolling patients.

Brian Culley, CEO of Lineage, said in a news release the company is pleased to see the improvements to outer retinal structure in the initial clinical study of RG6501.

“These data suggest that OpRegen RPE cells may provide direct support to the patients’ remaining retinal cells within atrophic areas, and that the improvements to retinal structure can be detected within the first three months following a single administration,” Culley said in a news release. “We look forward to additional, future clinical data updates on the OpRegen program from our partners, Roche and Genentech.”

Presentation highlights noted that all 5 patients enrolled in cohort 4 who had extensive coverage of the GA lesion with the surgical bleb containing RG6501 in suspension, demonstrated evidence of improvement in outer retinal structure as assessed by optical coherence tomography (OCT) within the first 3 months after treatment.

• Retinal structural improvement in the patients described above were initially observed on day 1 (n=1), day 14 (n=1), month 1 (n=2), and month 3 (n=1).
• Maintenance and/or greater improvements in retinal structure were observed over time.

Structural improvement (as defined below) was only observed within GA lesions with extensive coverage with the surgical bleb suggesting that Lineage Cell Therapeutics Inc. today announced that the results of imaging analyses demonstrating rapid improvement in outer retinal structure from patients enrolled in a Phase 1/2a clinical study of RG6501.

• RPE cells provide support to the remaining retinal cells within atrophic areas.
• These 5 patients had an average of 4.4 letter BCVA gain by 3 months and 12.8 letter BCVA gain by 1 year compared to baseline.
• OCT images were reviewed by three independent graders from the day after surgery to the start of structural improvement and subsequent follow-up visits.
• Structural improvement on OCT was qualitatively defined as meeting all pre-specified criteria including: 1) reduction in outer plexiform layer (OPL) and/or inner nuclear layer (INL) subsidence; 2) reappearance of external limiting membrane (ELM); and 3) increased hyperreflectivity and/or thickness of RPE and/or Bruch’s membrane or reduction of hypertransmission on at least two non-adjacent B scans.

The patient who demonstrated retinal structure improvement as early as day 1 following OpRegen subretinal delivery exhibited persistence of structural improvement as measured by OCT, with resolution of areas of complete RPE and outer retinal atrophy (cRORA) features at 24 months following treatment. Durability of retinal structure improvements beyond the 12-month primary endpoint is still being evaluated in other patients.