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  • Glaucoma, Neuro-Ophthalmology/Orbit, Retina/Vitreous

    Review of: Phase I NT-501 ciliary neurotrophic factor implant trial for primary open-angle glaucoma

    Goldberg J, Beykin G, Satterfield K, et al. Ophthalmology Science, September 2023

    Results of a small phase I study investigating the safety of a ciliary neurotrophic factor (CNTF)–secreting implant for patients with primary open-angle glaucoma (POAG) suggest that the implant is well-tolerated and may have some neuroprotective effects on the retina.

    Study design

    This was a phase I, open-label, prospective clinical trial involving 11 patients with POAG who underwent transscleral implantation of a CNTF-secreting encapsulated cell device in one eye. This technology is designed to deliver long-term, continuous CNTF to the retina. Patients demonstrating progression of POAG were eligible for enrollment. The primary outcome was safety, which was assessed for 18 months post-implant. Some structural and functional results were also recorded for secondary analysis.


    All patients tolerated the NT-501 implant without serious adverse events. Visual acuity and contrast sensitivity demonstrated a mild decrease in the fellow, untreated eye when compared to the study eye. Mean deviation on Humphrey visual field tests worsened in fellow eyes and improved in study eyes. Implanted eyes showed an increase in retinal nerve fiber layer thickness that was not found to be a result of cystoid macular edema. No differences were noted in pattern electroretinogram improvements between treated vs fellow eyes.


    This was a small, nonrandomized phase I study and, thus, was not powered to assess efficacy. It also only enrolled patients with POAG, so results may not be generalizable to other populations.

    Clinical significance

    There is a critical need for neuroprotective treatments for glaucoma to slow disease progression, especially since current management options focus only on lowering IOP. Promising results from this study have enabled progression to phase II clinical trials, which are currently enrolling. If successful, this implant would generate a new class of drugs available for patients with glaucoma.

    Financial Disclosures: Dr. Kimberly Gokoffski discloses no financial relationships.