New Research Highlights Long-Term Advantages of Retinal Implant for Vision Loss
Recent research has unveiled significant long-term benefits associated with a neuroprotective surgical implant designed for individuals suffering from macular telangiectasia type 2 (MacTel), a rare retinal condition that progressively impairs central vision. This groundbreaking study, carried out by scientists at Scripps Research in collaboration with the National Institutes of Health (NIH) and sponsored by Neurotech Pharmaceuticals, indicates that the implant may effectively slow vision deterioration.
Historically, patients with MacTel had limited treatment options, but the findings of this study, published in the journal NEJM Evidence, suggest a promising alternative. The trials evaluated a device known as ENCELTO (revakinagene taroretcel-lwey), which is surgically implanted and continuously releases a therapeutic protein aimed at preserving vision.
Conducted across 47 international sites, the Phase III clinical trials involved 228 participants over a 24-month follow-up period. The trials, coordinated by a network of global clinicians and researchers, have provided compelling evidence supporting the efficacy of ENCELTO, which was approved by the US Food and Drug Administration (FDA) in March 2025. This approval marks a significant milestone as ENCELTO becomes the first authorized treatment for MacTel and the first cell-based neuroprotective intervention for any neurodegenerative retinal disease.
The study's design consisted of two randomized trials that, despite variations in participant recruitment and disease severity, demonstrated that the implant could indeed slow down the degeneration of light-sensitive retinal cells. One trial revealed a substantial 54.8% reduction in the rate of ellipsoid zone loss, indicative of retinal cell degeneration, while the second trial showed a 30.6% reduction--a statistically significant finding nonetheless.
In addition to structural changes in the retina, the research assessed visual function through various measures, including microperimetry and reading speed. Results from microperimetry indicated a statistically significant deceleration in visual function loss, particularly in the trial that exhibited greater preservation of photoreceptor cells. However, outcomes related to reading speed displayed more variability, underscoring the complexities associated with evaluating functional vision loss in a gradually progressing disease like MacTel.
The overall trend across both trials supports the notion that ENCELTO provides long-term benefits, especially when treatment is initiated before extensive retinal cell loss occurs. Participants reported tolerating the implant well, with minimal side effects observed. Notably, the treatment proved effective regardless of the participant's initial vision status or disease stage, suggesting that early intervention could help sustain functional vision as MacTel advances.
Looking ahead, researchers plan to investigate whether the benefits of the implant continue or even improve beyond the initial 24-month period. Additionally, they aim to explore the reasons behind the differing levels of improvement among participants, which could aid in identifying specific patient subgroups most likely to benefit from the therapy.
The consistent preservation of retinal cells observed across both trials bolsters confidence in the therapeutic strategy employed by ENCELTO. As researchers refine their approach to treating MacTel, the expectation is that even greater improvements in vision may be realized over time. Furthermore, the ability of ENCELTO to deliver sustained, targeted doses of therapeutic proteins directly to the retina opens avenues for potential adaptation in treating a variety of neurovascular degenerative diseases beyond MacTel.