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Study on the Safety and Effectiveness of Ripasudil Eye Drops for Patients with Fuchs Endothelial Corneal Dystrophy After Descemetorhexis

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying Fuchs Endothelial Corneal Dystrophy, a condition affecting the cornea, which is the clear front part of the eye. The study is investigating the safety and effectiveness of Ripasudil (also known by its code name K-321) eye drops. These eye drops are being tested to see if they can help improve vision after a procedure called descemetorhexis, which involves removing a small part of the cornea to treat the disease.

The purpose of the study is to see how quickly vision improves after using the Ripasudil eye drops compared to a placebo, which is a substance with no active medication. Participants will be randomly assigned to receive either the Ripasudil eye drops or the placebo. The study will last for a total of 12 weeks, with an additional two-week period where the dose is gradually reduced, followed by a 38-week follow-up phase to monitor long-term effects.

Throughout the study, participants will have their vision checked regularly to see how well they can see letters on a chart, which is a common way to measure vision improvement. The study aims to determine if the eye drops can help achieve a significant improvement in vision during the first 12 weeks after the procedure. Participants will also be monitored for any changes in the cornea and any side effects from the treatment.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial treatment phase

    The study begins with the administration of ripasudil eye drops. These are used to treat Fuchs Endothelial Corneal Dystrophy, a condition affecting the cornea of the eye.

    The eye drops are applied directly to the eye, a method known as ocular use.

  2. Step 2

    Treatment duration

    The treatment with ripasudil eye drops lasts for a period of 12 weeks. During this time, the effect on vision improvement is closely monitored.

    The goal is to achieve an improvement in visual acuity, measured by the ability to read letters on an eye chart.

  3. Step 3

    Dose taper phase

    After the initial 12-week treatment period, there is a two-week phase where the dosage of the eye drops is gradually reduced. This is known as the dose taper phase.

  4. Step 4

    Follow-up phase

    Following the dose taper phase, there is a 38-week follow-up period. During this time, the long-term effects of the treatment are assessed.

    The follow-up phase helps to determine the overall safety and effectiveness of the treatment.

Who can join the trial?

7 criteria

  • The person must be at least 18 years old.
  • The person must have a diagnosis of Fuchs Endothelial Corneal Dystrophy (FECD), which is a condition affecting the cornea of the eye.
  • The person must have a specific pattern in the cornea called confluent central guttae that can be removed by a procedure called descemetorhexis, which involves removing a small circular area of the cornea.
  • The person must have one of the following vision issues in the study eye:
    • Vision measured at 78 letters or fewer on a specific eye test called ETDRS, which is similar to a Snellen chart reading of 20/32 or worse.
    • Vision measured at more than 78 letters on the ETDRS test but experiencing problems like glare, stray light, or difficulty seeing contrasts.
    • The person must be able to understand and sign a written consent form, agreeing to follow the study's rules and procedures.
    • After the descemetorhexis procedure, it must be confirmed that the central area of the cornea with confluent guttae has been removed, measuring between 4.5 to 5.5 mm in diameter.

Who cannot join the trial?

5 criteria

  • Patients who do not have Fuchs Endothelial Corneal Dystrophy cannot participate. This is a condition affecting the clear front part of the eye called the cornea.
  • Patients who are not within the specified age range cannot participate. The age range is typically defined by the study.
  • Patients who are not part of the specified clinical trial groups cannot participate. These groups are usually defined by the study based on certain characteristics.
  • Patients who are not male or female cannot participate, as the study includes both genders.
  • Patients who are considered part of a vulnerable population cannot participate. This refers to groups who may need special protection in research, such as children or those with certain disabilities.
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Investigated drugs

Ripasudil (K-321) Eye Drops are being studied to see if they can help improve vision in people with Fuchs Endothelial Corneal Dystrophy. This condition affects the cornea, the clear front part of the eye, and can lead to vision problems. The eye drops are used after a procedure called descemetorhexis, which involves removing a layer of cells from the cornea. The study aims to find out if these eye drops can help improve vision by increasing the number of letters a person can read on an eye chart.

What is already known about the treatment

Ripasudil (K-321) – This medication is administered as eye drops and is currently being studied in clinical trials for its potential use in treating Fuchs Endothelial Corneal Dystrophy. It is in the Phase 3 stage of clinical trials, which means it is being tested for safety and effectiveness in a larger group of people. The main therapeutic indication for Ripasudil is to improve visual acuity in patients with this specific corneal condition. At the molecular level, Ripasudil works by inhibiting a protein called Rho kinase, which helps to reduce intraocular pressure and improve corneal health. It is classified pharmacologically as a Rho kinase inhibitor.

Investigated diseases

Fuchs Endothelial Corneal Dystrophy – This is an eye condition that affects the cornea, the clear front surface of the eye. It is characterized by the gradual deterioration of the endothelial cells, which are responsible for maintaining the cornea's clarity by pumping out excess fluid. As these cells are lost, fluid builds up in the cornea, leading to swelling and clouding of vision. Over time, this can cause blurred vision, glare, and discomfort, especially in the morning. The disease typically progresses slowly and may initially affect one eye before the other. It is more common in older adults and can lead to significant visual impairment if not managed.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-511752-40-00Protocol codeK-321-301Estimated enrolment41 patientsSponsorKowa Research Institute Inc.

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