How Does Ciliary Neurotrophic Factor Work?

Ciliary neurotrophic factor (CNTF) is a novel cell-based therapy used to treat macular telangiectasia type 2, a retinal disease that can lead to vision loss in adults. Ciliary neurotrophic factor slows down disease progression and loss of vision by supporting the survival of photoreceptors, the special cells in the retina that enable vision.

Macular telangiectasia type II (MacTel) is a neurodegenerative eye disorder that causes abnormal generation of blood vessels and lesion in the pigmented tissue of the retina. This leads to degeneration and loss of the rods and cones (photoreceptors) in the macula, the central portion of the retina that is responsible for vision.

Photoreceptors are light receiving cells that convert light into electrical signals, and send them through the optic nerve to the brain, providing us with vision. CNTF is a natural protein produced by specialized cells in the eye known as Muller cells and retinal pigment epithelium (RPE) cells. CNTF is neuroprotective and essential for the maintenance and survival of photoreceptor cells.

Ciliary neurotrophic factor therapy is a surgical process in which a semi-permeable capsule is implanted inside the eye in the vitreous cavity. The capsule has genetically engineered allogeneic RPE cells which continuously secrete CNTF, helping slow down the degeneration of photoreceptors and consequent vision loss.

Ciliary neurotrophic factor and CNTF derivatives are being investigated for use in other diseases also, because, in addition to the retina, CNTF plays similar protective roles in other nerve cells (motor neurons), as well as non-neuronal cells in the central nervous system, and cells of organs such as liver, bones, and skeletal muscles.

Currently, the first and only cell-based therapy for treating MacTel type 2 is revakinagene taroretcel-lwey (Encelto), approved by the FDA on March 06, 2025. Encelto contains 200,000 to 440,000 allogeneic RPE cells which secrete recombinant human ciliary neurotrophic factor (rhCNTF). Encelto is expected to be available for patients in the U.S.A from June 2025.

Common side effects of ciliary neurotrophic factor include the following:

• Bleeding in the eye’s outer membrane (conjunctival hemorrhage)
• Delayed dark adaptation
• Eye pain
• Foreign body sensation in the eye
• Suture-associated complications such as:
  • Irritation, itching and pain in the sutures
  • Wound opening
  • Inflammatory cell clusters around the sutures (suture granulomas)
• Excessive constriction of pupils (miosis)
• Red eye (conjunctival hyperemia)
• Eye discomfort
• Eye itching (pruritus)
• Vitreous hemorrhage
• Headache
• Blurred vision
• Dry eye
• Eye irritation
• Vitreous floaters
• Cataract
• Severe vision loss
• Eye discharge
• Cell deposits in the anterior eye chamber
• Inflammation of the iris and ciliary body in the eye (iridocyclitis)
• Implant related complications such as:
  • Implant extrusion
  • Retinal tear and detachment
  • Inner eye infection that can potentially cause blindness (infectious endophthalmitis)

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of FDA-approved ciliary neurotrophic factor include:

• Encelto
• revakinagene taroretcel
• revakinagene taroretcel-lwey