A Phase 3 interventional study of Ripasudil and Placebo in Fuchs Endothelial Corneal Dystrophy, sponsored by Kowa Research Institute, Inc.. Completed at 50 sites in 6 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-27.
Sponsored by Kowa Research Institute, Inc. (part of Kowa Company, Ltd.) · Phase 3, Interventional, and Treatment
A study to assess the safety and efficacy of K-321 in participants with FECD after descemetorhexis.
92 studies on the registry are indexed under Fuchs' Endothelial Dystrophy; 27 are open to participants now.
This study's enrollment of 107 is above the median of 50 across 62 interventional studies indexed under Fuchs' Endothelial Dystrophy.
Browse Fuchs' Endothelial Dystrophy studies →Kowa Research Institute, Inc. is the lead sponsor of 47 studies on the registry; 1 is open to participants now.
Of its 20 completed or terminated interventional studies of FDA-regulated products, 9 (45%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Is a female patient of and any of the following is true:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
K-321 ophthalmic solution four times daily (QID) for 12 weeks followed by a two-week gradual dose taper phase and 38-week follow-up phase
Drug: Ripasudil
Placebo ophthalmic solution QID for 12 weeks followed by a two-week gradual dose taper phase and 38-week follow-up phase
Drug: Placebo
K-321 ophthalmic solution
Also known as: K-321
Placebo ophthalmic solution
Time to improvement in best corrected (distance) visual acuity (BCVA) by ETDRS letter score during the first 12 weeks
Time frame: Baseline to Week 12
Time to improvement in best corrected (distance) visual acuity (BCVA) by ETDRS letter score during the first 12 weeks
Time frame: Baseline to Week 12
Time to achievement in best corrected (distance) visual acuity (BCVA) by ETDRS letter score during the first 12 weeks
Time frame: Baseline to Week 12
Central corneal ECD at Week 12
Central corneal endothelial cell images will be captured by non-contact specular microscopy.
Time frame: Week 12
Time to achievement of no corneal edema during the first 12 weeks
Time frame: Baseline to Week 12
Time to exceed in BCVA pre-DSO ETDRS letter score during the first 12 weeks
Time frame: Baseline to Week 12
Ran from Mar 2023 to primary completion in May 2025, 25 months.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in May 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: K-115
Fuchs' Endothelial Dystrophy →
Kowa Research Institute, Inc. →