Thymosin β4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial

Cornea. 2015 May;34(5):491-6. doi: 10.1097/ICO.0000000000000379.


Purpose: Standard therapies for severe dry eye are limited and fail to resolve the problem. The purpose of this study was to evaluate the safety and efficacy of Thymosin β4 eye drops (RGN-259) as a novel therapy for severe dry eye disease (including that associated with graft vs. host disease).

Methods: A small, multicenter, randomized, double-masked, placebo-controlled 56-day phase 2 clinical trial including a 28-day follow-up at 2 US sites. Nine patients with severe dry eye were treated with either RGN-259 (0.1%) or vehicle control 6 times daily over a period of 28 days. Dry eye sign and symptom assessments, such as ocular discomfort (using the OSDI questionnaire) and corneal fluorescein staining (using the NEI workshop grading system), were evaluated at various time points.

Results: Statistically significant differences in both symptom and sign assessments, were seen at various time points throughout the study. Of particular note at day 56, the RGN-259-treated group (12 eyes) had 35.1% reduction of ocular discomfort compared with vehicle control (6 eyes) (P = 0.0141), and 59.1% reduction of total corneal fluorescein staining compared with vehicle control (P = 0.0108). Other improvements seen in the RGN-259-treated patients included tear film breakup time and increased tear volume production.

Conclusions: In this small trial, RGN-259 eye drops were safe and well tolerated and met key efficacy objectives with statistically significant symptom and sign improvements, compared with vehicle control, at various time intervals, including 28-days posttreatment. CLINICAL TRIAL REGISTRATION--URL: Unique identifier: NCT01393132.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cornea / metabolism
  • Double-Blind Method
  • Dry Eye Syndromes / diagnosis
  • Dry Eye Syndromes / drug therapy*
  • Female
  • Fluorescein / metabolism
  • Fluorescent Dyes / metabolism
  • Fluorophotometry
  • Follow-Up Studies
  • Graft vs Host Disease / drug therapy
  • Humans
  • Male
  • Microfilament Proteins / adverse effects
  • Microfilament Proteins / therapeutic use*
  • Middle Aged
  • Ophthalmic Solutions / therapeutic use
  • Surveys and Questionnaires
  • Tears / metabolism
  • Thymosin / adverse effects
  • Thymosin / therapeutic use*


  • Fluorescent Dyes
  • Microfilament Proteins
  • Ophthalmic Solutions
  • thymosin beta(4)
  • Thymosin
  • Fluorescein

Associated data