Treating Macular Telangiectasia With Encelto

Written by Courtney Krueger, PharmD, BCPS
Medically Reviewed by Patricia Weiser, PharmD on April 08, 2025
5 min read

Macular telangiectasia type 2, also known as MacTel, is a rare eye disease that can lead to vision loss. Although MacTel rarely leads to total blindness, it does cause a decline of sharp central vision, which can interfere with daily tasks such as reading, writing, and driving. 

Encelto is the first medicine approved  to treat MacTel.

Encelto is a small capsule about the size of a grain of rice that is placed in your eye by an ophthalmologist (an eye specialist) during an outpatient surgery. The capsule contains cells that produce proteins for treatment of MacTel. These proteins are continuously produced for a long time.

Photoreceptors are important light-sensing cells that allow us to see in color and in dark settings. MacTel causes you to lose photoreceptors in both of your eyes over time. Encelto helps to slow the loss of your photoreceptors through production and release of a protein called recombinant human ciliary neurotrophic factor (CNTF). This protein is thought to protect the photoreceptors in your eye, which can help slow vision loss.

Two identical studies were done to look at how well Encelto works for people with MacTel. The studies included 228 adults who were diagnosed with MacTel. The people were split into two groups and received either Encelto in one eye or a sham (non-treatment) surgery in one eye. 

People in the studies were 40 to 78 years old with an average age of 60. About 88% of people in the studies were White, 4% were Asian, 3% were Black or African American, 0.5% were American Indian, and the remainder did not report race or were categorized as “other”. 

The researchers evaluated how well Encelto works for MacTel by looking at the rate of photoreceptor loss over 24 months.

In the first study, there was a 54.8% slower rate of photoreceptor loss with Encelto than with sham surgery. In the second study, there was a 30.6% slower rate of photoreceptor loss with Encelto than with sham surgery.

Your results may differ from what was seen in clinical studies.

You may experience side effects after surgical placement of the Encelto capsule. For the first week after Encelto placement you should take the following precautions.

  • Avoid lifting anything over 20 pounds.
  • Keep water out of your eyes.
  • Wear glasses or protective eyewear during the day.
  • Wear an eye shield at night.

You should not drive after Encelto placement until your eye shield has been removed and your vision has recovered. Your health care provider will tell you when it is safe for you to drive.

You will need to use two types of eye drops after Encelto placement. One eye drop is an antibiotic to prevent infection, and you will use it for seven days. The other eye drop is a corticosteroid eye drop to reduce inflammation, and you will use it for 28 days. You should use the eye drops exactly as recommended by your health care provider.

These are not all of the possible side effects of Encelto. Talk with your health care provider if you are having symptoms that bother you. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088.

Although there is not a lot of information on the long-term safety of Encelto, people enrolled in the early phases of the studies have been followed for up to 108 months (about nine years). Overall, 90% of people experienced at least one side effect, most of which were mild, temporary, and happened within three months after Encelto placement. The most common serious complications included suture-related complications in 2.3% of people, implant extrusion or expulsion (the implant working its way out of the eye) in 1.4% of people, and blurred vision or vision problems in 1.4% of people.

Encelto is a unique type of treatment, and there are some considerations you should be aware of.

  • You may have trouble adjusting from bright lighting conditions to dark lighting conditions after Encelto placement. This is called delayed dark adaptation. If this occurs, it is unknown how long the symptoms will last, and you should take some precautions.
    • Your driving may be impaired. You may have trouble seeing objects, pedestrians, or road signs when moving from bright light to dim light.
    • You may have trouble navigating dark environments. Consider using a flashlight, nightlight, or motion-activated lighting.
    • Consider wearing sunglasses or tinted lenses in bright light to help you transition from light to dark.
  • Your Encelto capsule may be removed from your eye by an eye surgeon if necessary. It is possible for the Encelto capsule to work its way out of your eye (called implant extrusion). Your health care provider will examine the placement of Encelto six months after surgery and then every year while the capsule is in your eye. If your implant is out of position, it can be repositioned by your eye surgeon. Symptoms of implant extrusion can include:
    • Uveitis (eye inflammation)
    • Vitreous hemorrhage
    • Eye pain occurring more than one year after implantation
    • Visibility of part of the Encelto capsule
  • You will receive an implant card, which should be given to a health care provider if you are in need of magnetic resonance imaging (MRI) at any time while your Encelto capsule is in your eye. This card contains important MRI safety information.

You will need to be enrolled in a patient support program known as ENCELTOconnect in order to receive Encelto. This program may be able to help with cost assistance. You can read more about the assistance program at this website.

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