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

What Was Tested

In this phase 3 trial, researchers set out to test Thymosin Beta-4 (full length).

It had two arms (groups): one (experimental) and Placebo Ophthalmic Solution (Vehicle for RGN-259 Ophthalmic Solution) (placebo comparator).

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

It is composed of the same excipients as RGN-259 but does not contain Tβ4.

The registry classes the interventions as drug.

More on the Plan

Neurotrophic keratopathy (NK) is a degenerative corneal disease that occurs as a result of partial or total impairment of trigeminal innervation.

Who Took Part

70 planned participants were the target.

It was open to people of any sex aged from 18 years with no upper age limit.

Healthy volunteers were not accepted; participants needed the condition being studied.

Examples of who could 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;. 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;.

The full record lists 10 inclusion and 21 exclusion criteria; among the exclusions: 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.

How the Study Was Run

It was run as a randomized, parallel-group and quadruple-blind study.

Because people in this Thymosin Beta-4 (full length) study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

Groups ran in parallel: each of the participants stayed in one arm throughout.

As a double-blind Thymosin Beta-4 (full length) study, the assignments were hidden from both participants and investigators until the end.

Those kept unaware of assignments: participant, care provider, investigator and outcomes assessor.

It started in 2023-04-11 with completion listed for 2026-04-30.

It ran at 36 sites in United States (29), Spain (4), Italy (2) and Poland (1).

Its stated primary purpose is treatment.

What Was Measured

Researchers chose this as the main measure: Percentage of subjects achieving complete healing of PED at Day 29 (time frame: Day 29).

It also tracked 5 secondary outcomes, for example Percentage of subjects achieving complete healing of PED at Day 29, Percentage change from baseline of lesion size, NK stage by Mackie classification, Visual Acuity determined by ETDRS and Corneal sensitivity inside the lesion determined by Cochet Bonnet aesthesiometer (Unit: mm).

What This Means in Plain Language

Put simply, this is a phase 3, randomized trial of Thymosin Beta-4 (full length) in 70 people.

It is still recruiting; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Thymosin Beta-4 (full length) compound page, all human trials.