Retina Society 2026: Implant reduces cavitation volume in MacTel 2

At Retina Society 2026, Jay Chhablani, MD, a professor of ophthalmology at the UPMC Vision Institute in Pittsburgh, discussed a post hoc analysis of phase 3 trials of revakinagene taroretcel-lwey (NCT03316300 and NCT03319849)1 in patients with macular telangiectasia (MacTel) type 2. Chhablani explained that cavitation refers to hypo-reflective, cyst-like spaces seen on optical coherence tomography (OCT) that are not true fluid-filled edema. He distinguishes these from cystoid macular edema (CME) by noting that a cyst accompanied by retinal thinning indicates MacTel, while thickening points to CME. He said these cavities represent structural degeneration, including Müller cell and photoreceptor damage, in eyes with MacTel type 2.

A higher proportion of treated eyes showed decreased cavitation volume

Using AI-based analytic tools, Chhablani said a higher proportion of implant-treated eyes had decreased cavitation volume compared with sham eyes, and that the difference between the two groups was statistically significant (categorical comparison, P = .003; rank-based ANCOVA, P = .023).¹ He attributed this to the implant's release of ciliary neurotrophic factor (CNTF), which he said slows neurodegeneration and contributes to long-term disease stabilization, while emphasizing that existing damage cannot be reversed.

Outer nuclear layer and ellipsoid zone integrity

Chhablani said the analysis also showed a slight thickening of the outer nuclear layer (ONL), which he said demonstrates photoreceptor cell bodies. He described this relative preservation, or slower thinning, as evidence of extended photoreceptor survival, calling it a critical outcome that further supports a neuroprotective role for CNTF.

The ellipsoid zone (EZ), the junctional border between the inner and outer segment layers, matters because the analysis showed a benefit even in areas of existing EZ damage, Chhablani said. He described a new index he helped develop, the Ellipsoid Zone Integrity Index (EZI), defined as the percentage of analyzed area exhibiting EZ atrophy, and said EZ loss was significantly less in implant-treated eyes. According to the presentation, this benefit was most pronounced within a 3-mm ring centered on the fovea and extended into a 100- to 200-μm penumbra surrounding the EZ atrophy border.¹

Chhablani acknowledged that post hoc analyses like this one were not predefined or pre-specified, creating a risk of bias, over-interpretation, or subset selection. He said the next step is carrying these biomarkers into a prospective study and correlating the structural findings with functional visual outcomes.

Reference
1. Chhablani J, Hatcher K, Hasan N, Hadziahmetovic M. Evaluation of outer retinal structures and cavitation volume in the phase 3 trials of revakinagene taroretcel-lwey. Presented at: Retina Society 59th Annual Scientific Meeting; September 23-26, 2026; Los Angeles, CA.