A groundbreaking milestone has been achieved in the field of ophthalmology with the FDA approval of ENCELTO, the inaugural cell-based therapy for MacTel, a rare neurodegenerative retinal disease. This approval follows the successful completion of Phase 3 clinical trials led by Scripps Research, in collaboration with the National Institutes of Health (NIH) and sponsored by Neurotech Pharmaceuticals. For individuals afflicted with MacTel, characterized by progressive central vision loss, the absence of approved treatments rendered this approval a significant advancement in the medical landscape.
The pivotal research published in NEJM Evidence on July 22, 2025, unveiled the outcomes of two parallel Phase 3 trials investigating ENCELTO (revakinagene taroretcel-lwey), an innovative implanted device designed to deliver a therapeutic protein continuously to safeguard retinal cells. Enrolling 228 participants across 47 global sites, these trials were instrumental in providing the compelling data that underpinned the FDA’s sanction of ENCELTO in March 2025. This marked a historic moment as it not only signified the first authorized therapy for MacTel but also introduced the pioneering concept of cell-based neuroprotective treatments for neurodegenerative retinal and central nervous system conditions.
The meticulous design of the trials ensured consistency in evaluating the efficacy of ENCELTO in impeding the deterioration of light-sensing retinal cells. While both trials demonstrated a notable deceleration in cell loss, variations in outcomes were observed, likely attributable to variances in disease severity among participants. Prof. Martin Friedlander, a key figure in the study and President of the Lowy Medical Research Institute, emphasized the significance of this achievement in altering the trajectory of MacTel progression. The implant’s delivery of ciliary neurotrophic factor (CNTF), a potent retinal neuron protector, through genetically engineered cells encapsulated in the eye’s posterior segment, exemplified a paradigm shift towards proactive vision preservation.
Noteworthy reductions in photoreceptor degeneration were a prominent highlight of the research, with ENCELTO showcasing a substantial 54.8% and 30.6% decrease in ellipsoid zone loss across the two trials. Functional assessments encompassing microperimetry and reading speed underscored the implant’s positive impact on retinal function, albeit with nuances in outcomes between the trials. Despite these nuances, the collective evidence reinforced ENCELTO’s enduring benefits, particularly when administered proactively. Notably, the implant exhibited favorable safety profiles and exhibited efficacy irrespective of baseline visual acuity, advocating for early intervention to optimize functional vision retention as MacTel progresses.
Looking ahead, Prof. Friedlander and his team are poised to delve into the sustained benefits of ENCELTO beyond the 24-month assessment window, with a focus on elucidating factors contributing to varying individual responses. The platform’s adaptability presents a promising avenue for addressing a spectrum of neurovascular degenerative disorders beyond MacTel, accentuating the transformative potential of targeted, sustained protein delivery to mitigate cell vulnerability.
Key Takeaways:
– ENCELTO, the pioneering cell-based therapy for MacTel, has garnered FDA approval post landmark Phase 3 trials.
– The implant’s delivery of CNTF signifies a breakthrough in neuroprotective retinal treatments, heralding a paradigm shift in vision preservation strategies.
– ENCELTO demonstrated significant reductions in photoreceptor loss and enhanced retinal function, supporting its long-term efficacy across diverse disease stages.
– Early intervention with ENCELTO showcased pronounced benefits, underscoring the imperative of timely treatment initiation in preserving functional vision in MacTel.
Tags: clinical trials, gene therapy
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