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Neurotrophic KeratopathyPhase 3NCT05555589

Assessment of the Safety and Efficacy of 0.1% RGN-259 Ophthalmic Solution for the Treatment of NK: SEER-2

A Phase 3 study testing RGN-259 in people with Neurotrophic Keratopathy, run by ReGenTree, LLC at 50 sites in 4 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The objective of this study is to compare the safety and efficacy of RGN-259 to placebo for the treatment of Neurotrophic Keratopathy (NK) Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Neurotrophic Keratopathy
What is being tested?
RGN-259
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
70 participants
Where
50 sitesin 4 countries
Study dates
11 Apr 2023to 28 Jul 2026
Phase
Phase 3
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Be male or female of any race, at least 18 years of age;
  • Have provided written informed consent;
  • Be able and willing to follow instructions, including participation in all study assessments and visits;
  • At the time of Visit 1, have documentation or observation of a Persistent Epithelial Defect (PED) in one or both eyes, defined as a corneal epithelial defect that has not resolved after 1 week of conventional treatment using non-preserved ocular lubricants, non-preserved topical ophthalmic antibiotics, oral doxycycline, patching, amniotic membrane, serum tears, and/or therapeutic contact lenses;
  • Have stage 2 or 3 neurotrophic keratopathy (Mackie Classification) in at least one eye of which the longest dimension (length or width) of the defect measures a minimum length of 1 mm (study eye) and which is confirmed by the Investigator not to be simply superficial punctate keratitis, at Visit 1;
  • Have evidence of decreased corneal sensitivity ≤40 mm using the Cochet-Bonnet aesthesiometer at Visit 1;
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  • Have BCVA score ≤75 letter counts in the study eye based on the ETDRS protocol;
  • Have at least one eye (the same eye) satisfy all criteria for d, e, f, g above;
  • Female subjects of child-bearing potential must be non-lactating and using and agree to continue using an acceptable method of contraception for at least 4 weeks prior to the first dose of study product and until 12 weeks after last dose, and have a negative urine pregnancy test during screening;
  • Male subjects must agree to use an adequate method of contraception.

Who cannot join

  • Have any condition that, in the opinion of the Investigator, would interfere with the subject's ability to complete the study, would interfere with the interpretation of safety or efficacy, or would present an undue risk to the subject.
  • Have any clinically significant slit-lamp findings in the study eye that in the opinion of the Investigator may interfere with the study parameters;
  • Clinically significant active blepharitis, meibomian gland dysfunction (MGD), or lid margin inflammation, or active ocular allergy in study eye that requires treatment that in the opinion of the investigator may interfere with the study parameters;
  • Have a Unanesthetized Schirmer's test score of ≤3 mm at Visit 1;
  • Have a lid function abnormality (ex. Lagophthalmos) which, in the opinion of the Investigator, is the primary cause of the persistent epithelial defect;
  • Have an ongoing ocular infection (bacterial, viral or fungal) or active inflammation (e.g., follicular conjunctivitis) in the study eye.
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  • History of any ocular surgery (including laser or refractive surgical procedures) within the three months before study enrollment.
  • Prior surgical procedure(s) for the treatment of NK (e.g., tarsorrhaphy, conjunctival flap, etc.) within the three months before study enrollment with the exception of amniotic membrane transplantation.
  • Have any planned ocular surgical procedures or are likely to require ocular surgery for the study eye during the study;
  • Have received Botox® injection to induce blepharoptosis in the study eye within 90 days prior to Visit 1;
  • Have used contact lenses (for therapeutic or refractive correction) in the study eye within 14 days prior to Visit 1, or anticipate use of contact lenses during the study period.
  • Have used OxervateTM in the study eye within the past 2 months;
  • Anticipate use of serum tears in the study eye during the study period.
  • Have a presence or history of any ocular or systemic disorder or condition that might hinder the efficacy of the study treatment or its evaluation, could possibly interfere with the interpretation of study results, or could be judged by the Investigator to be incompatible with the study visit schedule or conduct;
  • Have used drugs which affect lacrimation or function of the trigeminal nerve within 30 days of Visit 1 or anticipate use of these systemic medication throughout the course of the study;
  • Have any autoimmune or chronic inflammatory disease that might have hindered the efficacy of the study treatment or its evaluation;
  • Be on topical (Ocular/Nasal) immunosuppressive therapy within 30 days prior to screening or is likely to require this during the course of the study;
  • Have a known allergy and/or sensitivity to the study product or its components;
  • History of drug, medication or alcohol abuse or addiction;
  • Have participated in an investigational drug study within 30 days prior to screening;
  • Have fever, inflammation, or systemic signs of illness suggestive of systemic or invasive infection, including COVID-19 or a positive test for COVID-19, within 2 weeks prior to first dose of study drug.

Trial locations and contacts

50 sites in 4 countries.

50 sites in 4 countries

United States41 sites

  • The Johns Hopkins Wilmer Eye Institute

    Baltimore, Maryland, 21287

  • Tufts Medical Center

    Boston, Massachusetts, 02111

  • Midwest Cornea Associates, LLC.

    Carmel, Indiana, 46290

  • Midwest Vision Research Foundation

    Chesterfield, Missouri, 63017

  • Northwestern

    Chicago, Illinois, 60611

  • University Hospitals Cleveland Medical Center

    Cleveland, Ohio, 44106

  • Cleveland Clinic, Cole Eye Institute

    Cleveland, Ohio, 44195

  • Retina Consultants of Southern Colorado

    Colorado Springs, Colorado, 80909

  • Nature Coast Clinical Research

    Crystal River, Florida, 34429

  • Cornea Associates of Texas

    Dallas, Texas, 75231

  • Connecticut Eye Consultants, P.C. Danbury Eye Physicians & Surgeons

    Danbury, Connecticut, 06810

  • Duke Eye Center

    Durham, North Carolina, 27710

  • Atlantic Eye

    Eatontown, New Jersey, 07724

  • Pacific ClearVision Institute

    Eugene, Oregon, 97401

  • Houston Eye Associates

    Houston, Texas, 77025

  • Harvard Eye Associates

    Laguna Hills, California, 92653

  • Huffman & Huffman, PSC

    Lexington, Kentucky, 40509

  • Loma Linda University Eye Institute

    Loma Linda, California, 92354

  • Advance Vision Research Institute

    Longmont, Colorado, 80503

  • Nvision Clinical Research, LLC

    Los Angeles, California, 90013

  • Cataract & Laser Institute of Southern Oregon

    Medford, Oregon, 97504

  • University of Miami - Bascom Palmer Eye Institute, Miami

    Miami, Florida, 33136

  • CliniVerse Research

    Mission, Texas, 78572

  • Vanderbilt Eye Institute

    Nashville, Tennessee, 37232

  • Virginia Eye Consultants

    Norfolk, Virginia, 23502

  • Metropolitan Eye Research and Surgery Institute

    Palisades Park, New Jersey, 07650

  • Scheie Eye Institute, University of Pennsylvania

    Philadelphia, Pennsylvania, 19104

  • UPMC Eye Center

    Pittsburgh, Pennsylvania, 15213

  • OHSU Casey Eye Institute

    Portland, Oregon, 97239

  • Oculus Research

    Raleigh, North Carolina, 27617

  • Black Hills Regional Eye Institute

    Rapid City, South Dakota, 57701

  • Stuart Terry Eye Associates

    San Antonio, Texas, 78212

  • MCOA Eye Care

    San Antonio, Texas, 78240

  • Thomas Eye Group, P.C.

    Sandy Springs, Georgia, 30328

  • University of Washington, Department of Ophthalmology

    Seattle, Washington, 98104

  • CORE, Inc. / Vita Eye Clinic

    Shelby, North Carolina, 28150

  • Washington University Eye Center

    St Louis, Missouri, 63108

  • Berkeley Eye Center

    Sugar Land, Texas, 77478

  • University of South Florida, Ophthalmolgoy

    Tampa, Florida, 33612

  • Montefiore Medical Center

    The Bronx, New York, 10467

  • Parker Cornea

    Vestavia Hills, Alabama, 35242

Other trials in United States

Italy4 sites

  • Università di Brescia

    Brescia, Brescia, 25123

  • Azienda Ospedaliero Universitaria Careggi

    Florence, Firenze, 50134

  • Ospedale San Raffaele s.r.l.

    Milan, Lombardy, 20132

  • Università degli Studi di Milano - ASST Santi Paolo e Carlo

    Milan, Lombardy, 20142

Other trials in Italy

Spain4 sites

  • IMO Barcelona, Grupo Miranza

    Barcelona, Barcelona, 08035

  • Hospital La Arruzafa

    Córdoba, Córdoba, 14012

  • Instituto Oftalmológico Fernández-Vega

    Oviedo, Principality of Asturias, 33012

  • Aiken Prevención & Cirugía Ocular

    Valencia, Valencia, 46004

Other trials in Spain

Poland1 site

  • Gabinet Okulistyczny Prof Edward Wylegala

    Katowice, Silesian Voivodeship, 40-594

Other trials in Poland

About this study

Official title: A Phase 3, Multi-Center, Randomized, Parallel, Double Masked, Placebo-Controlled Clinical Study to Assess the Safety and Efficacy of 0.1% RGN-259 Ophthalmic Solution for the Treatment of Neurotrophic Keratopathy (SEER-2)

The objective of this study is to compare the safety and efficacy of RGN-259 to placebo for the treatment of Neurotrophic Keratopathy (NK)

Read the detailed description

Neurotrophic keratopathy (NK) is a degenerative corneal disease that occurs as a result of partial or total impairment of trigeminal innervation. The resulting loss of corneal sensitivity (anesthesia) leads to a reduction in lacrimation and a decline in status, metabolism, and mitosis of corneal epithelial cells.

Being tested
RGN-259, Placebo
Keywords
Neurotrophic Keratitis, NK

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • RGN-259Drug

    Also called Tβ4, Thymosin Beta 4, Timbetasin

    A preservative-free, sterile eye drop solution containing Tβ4 for direct instillation into study eye(s), five times per day for 28 days

  • PlaceboDrug

    Also called Vehicle Control

    It is composed of the same excipients as RGN-259 but does not contain Tβ4. Direct instillation into study eye(s), five times per day for 28 days

Study groups in NCT05555589
Study groupRoleWhat they receive
0.1% RGN-259 Opthalmic SolutionExperimentalIt is a preservative-free, sterile eye drop solution containing Tβ4 for direct instillation into study eye(s), five times per day for 28 days
Receives: Drug: RGN-259
Placebo Ophthalmic Solution (Vehicle for RGN-259 Ophthalmic Solution)Placebo comparatorIt is composed of the same excipients as RGN-259 but does not contain Tβ4
Receives: Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Percentage of subjects achieving complete healing of PED at Day 29

    Percentage of subjects achieving complete healing of the Persistent Epithelial Defect (PED) at Day 29 determined by corneal fluorescein staining as measured by the Central Reading Center.

    Measured: Day 29

Secondary outcomes (5)

  1. Percentage of subjects achieving complete healing of PED at Day 29

    Percentage of subjects achieving complete healing of the PED determined by corneal fluorescein staining as measured by the Investigator.

    Measured: Day 29

  2. Percentage change from baseline of lesion size

    Percentage change from baseline of lesion size determined by corneal fluorescein staining (measurements of greatest dimension of fluorescein staining)

    Measured: Day 8, 15, 22, 29, 36, and 43

  3. NK stage by Mackie classification

    NK stage graded according to the Mackie classification (Stage I, II, III. Higher scores mean a better or worse outcome)

    Measured: Day 8, 15, 22, 29, 36, and 43

  4. Visual Acuity determined by ETDRS

    Visual Acuity determined by Early Treatment of Diabetic Retinopathy Study (ETDRS)

    Measured: Day 8, 15, 22, 29, 36, and 43

  5. Corneal sensitivity inside the lesion determined by Cochet Bonnet aesthesiometer (Unit: mm)

    Measured: Day 8, 15, 22, 29, 36, and 43

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted27 Sep 2022
  2. Study start11 Apr 2023
  3. Primary completion28 Jul 2026
  4. Study completion28 Jul 2026

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
70 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05555589
Sponsor's protocol ID
RGN-NK-302
Status last verified
Nov 2026
First submitted
15 Sep 2022
Last updated
5 Nov 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing RGN-259 in people with Neurotrophic Keratopathy, run by ReGenTree, LLC at 50 sites in 4 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 10 inclusion and 21 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 5 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 50 sites in United States, Italy, Spain, Poland. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Percentage of subjects achieving complete healing of PED at Day 29 (time frame: Day 29). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05555589.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Nov 2026.

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