Long-Term Follow-Up on Patients Treated With CNTF-Producing Encapsulated Cell Therapy for Geographic Atrophy in Dry AMD

Document Type

Conference Proceeding

Publication Date

6-2025

Publication Title

Investigative Ophthalmology and Visual Science

Abstract

Purpose : Dry age-related macular degeneration (AMD) remains a leading cause of blindness in people age 55 or older and treatment options remain limited to this date. Encapsulated cell-based delivery of ciliary neurotrophic factor (CNTF), a neuroprotective agent, was studied in a pilot, proof of concept randomized, sham controlled study in 2007. This is a multicenter, long-term follow-up on original study participants to evaluate the long-term efficacy of treatment.

Methods : 22 out of the 51 original study patients (baseline mean age 76±7 years) with GA related to dry AMD were retrospectively analyzed. The study eye had been randomized to treatment (19 eyes) or sham (4 eyes), whereas fellow eyes served as controls. Patients were clinically followed for 127±46 months. A subset of 12 patients (9 treatment, 3 sham, 12 fellow eyes) received Heidelberg Engineering fundus autofluorescence (FAF) imaging at multiple timepoints, allowing accurate measurements of GA growth over 61±38 months. The area of GA was measured at FAF baseline and last follow-up, a square-root transformation was performed and paired-sample t-tests were used to compare study eyes to respective fellow eyes.

Results : The implant was well tolerated and visual acuity (VA) at last follow-up was equal or better in treated compared to fellow eyes. The size of GA at FAF baseline was significantly larger in eyes randomized to treatment (335±201 arbitary units, au) compared to fellow eyes (322±208 au; p=0.032). GA size at FAF follow-up was significantly larger in fellow eyes (501±249 au) compared to treated eyes (454±217 au; p=0.019). The monthly growth rate was significantly slower in treated (5.8±3.6 au) versus fellow eyes (7.9±5.5 au; p=0.011). There were no significant differences in GA size or monthly growth rate when comparing sham eyes to their fellow eyes (p-values 0.175-0.452).

Conclusions : The initial study protocol had a follow-up time of 12 months, which is likely too short to detect changes in a slowly progressing disease such as GA. Furthermore, VA is not an optimal marker for success, especially since subfoveal involvement was no exclusion criteria in the original study. This longitudinal analysis indicates that CNTF treatment significantly slows the progression of GA when analyzed with a longer follow-up time. CNTF therapy could be a valuable treatment option for patients with GA.

Volume

66

Issue

8

First Page

6276

Comments

Association for Research in Vision and Ophthalmology ARVO Annual Meeting, May 4-8, 2025, Salt Lake City, UT

Last Page

6276

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