0.1% RGN-259 (Thymosin ß4) Ophthalmic Solution Promotes Healing and Improves Comfort in Neurotrophic Keratopathy Patients in a Randomized, Placebo-Controlled, Double-Masked Phase III Clinical Trial

Sosne G, Kleinman HK, Springs C, Gross RH, Sung J, Kang S · International Journal of Molecular Sciences

The primary endpoint, complete healing of the epithelial defect at four weeks, was not met: 6 of 10 on RGN-259 against 1 of 8 on vehicle, p=0.0656 by Fisher's exact test. The paper also reports an ad hoc chi-square at p=0.0400 while stating that its large-sample assumption is violated, and an ad hoc odds ratio near 18 (p=0.0737). Two weeks after treatment stopped the healing difference reached p=0.0359, the one healed vehicle eye having relapsed by then. Mackie disease stage favoured treatment at days 29, 36 and 43 (p=0.0818, 0.0625 and 0.0467); time to healing did not (p=0.0829, Kaplan-Meier). Ocular discomfort, foreign-body sensation and dryness improved against vehicle at several visits, while photophobia and burning did not. One adverse event across the trial was judged treatment-related.

Population

Patients with stage 2–3 neurotrophic keratopathy and persistent corneal epithelial defects

Intervention

0.1% RGN-259 (Tβ4) eye drops for 28 days

Comparator

Vehicle

Limitations

Labelled phase III and stopped early at 18 participants of a planned 46. The paper gives the reason as slow recruitment in a rare disease; the registration, NCT02600429, gives it as a business decision. Randomisation left the vehicle group older, 72.5 years against 63.7, and with the larger defect, a median 7.375 against 6.570 mm², and the paper says some of the symptom differences follow from those baseline gaps. The significance the abstract leans on comes from analyses the paper itself labels ad hoc or acknowledges as invalid at this sample size. Three authors are employed by ReGenTree or its parent company, and ReGenTree employees designed the study.