Future of Macular Telangiectasia Treatment Could Alleviate Worst Symptoms

Macular telangiectasia (MacTel) has long gone without a consensus treatment modality to address the loss of central vision in those who are diagnosed with the condition. However, with the date for an FDA decision on the NT-501 ocular implant approaching in December, a real possibility of treatment for this eye condition is on the horizon.

MacTel is an eye condition that primarily affects patients 40 years and older and is defined by the loss of central vision.¹ The condition can appear as tiny blood vessels that surround the fovea, which is in the center of the macula. There are 2 types of MacTel that can affect a patient: type 1, which is usually referred to as macular edema, and type 2, which affects approximately 0.1% of adults 40 years and older. Type 2 is defined by tiny blood vessels becoming abnormal and potentially dilating. Type 1 involves tiny aneurysms forming as blood vessels dilate.

Macular telangiectasia can cause loss of central vision and presently has no approved treatment options. | Image credit: Satjawat - stock.adobe.com

Although the result of MacTel is quite severe, people do not have symptoms of the condition during its early stages. This leads to distorted vision, blurring, and loss of central vision over time. Ophthalmologists can evaluate the eye through optical coherence tomography (OCT) to identify small crystals in the macula if MacTel is suspected. Pigment clumps, lipid deposits around the macula, and discoloration of the macula are all also signs of MacTel. Patients with diabetes and hypertension are at an increased risk for type 2 MacTel, whereas type 1 is associated with Coat disease, a rare eye disorder found primarily in men.¹ However, it is mostly unknown what causes the condition.

The loss of central vision is a severe symptom of MacTel that can have life-changing implications for the patient. Concerningly, there are presently no effective methods of treating the condition. Treatments and therapies such as photocoagulation, photodynamic therapy, and intravitreal triamcinolone acetonide have not proven effective in improving visual acuity.²

Anti–vascular endothelial growth factor (anti-VEGF) drugs can offer some relief by slowing the growth of abnormal blood cells and reducing the leakage.² However, improvement of long-term outcomes is more controversial, as some studies claim there to be no improvement in visual acuity whereas others have reported slight improvements. The reduction of retinal thickness brought on by these drugs is also temporary.

However, new treatments are being looked into to treat MacTel. The most promising of them, NT-501, is an ocular implant that is able to deliver therapeutic doses of ciliary neurotrophic factor (CNTF) into the retina directly and is able to sustain the doses through 24 months.³

A phase 3 trial (NCT03316300) found that the rate of change in the ellipsoid zone, which demonstrates the change in a rate of the loss of photoreceptors, was statistically significant in both protocol A, which evaluated patients with type 2 MacTel, and in protocol B, which evaluated patients with type 1 MacTel.³ Patients in protocol A had a 56.4% rate of reduction and the patients in protocol B had a 29.2% rate of reduction. The implant was also found to be safe and well tolerated in these groups. The FDA has agreed to review the biologic license application for NT-501, with a Prescription Drug User Fee Act date set for December 17 of this year. This implant would provide the first proven treatment for MacTel should it be approved by the FDA.

MacTel remains a rare eye condition that affects the vision of those who are living with the condition. Treatment remains the biggest unmet need in patients with MacTel but this can soon change with a new treatment on the horizon. Should it be approved, the implant could represent a huge stride in helping people with MacTel to reduce the effects of their condition and keep their central vision for a longer amount of time. Regardless of the outcome of the approval, future studies into the condition should focus on maintaining patients’ diminishing central vision.

References

1. Tubert D. What is macular telangiectasia? American Academy of Ophthalmology. April 27, 2023. Accessed August 30, 2024. https://www.aao.org/eye-health/diseases/macular-telangiectasia
2. Kedarisetti KC, Narayanan R, Stewart MW, Gurram NR, Khanani AM. Macular telangiectasia type 2: a comprehensive review. Clin Ophthalmol. 2022;16:3297-3309. doi:10.2147/OPTH.S373538
3. Delaney-Gesing A. Neurotech Pharma earns BLA priority review for MacTel cell therapy. Eyes on Glance. June 24, 2024. Accessed August 30, 2024. https://glance.eyesoneyecare.com/stories/2024-06-24/neurotech-pharma-earns-bla-priority-review-for-mactel-cell-therapy/