1 · Growth factors & blood derivatives
Thymosin β4 — RGN-259
Review — modulators of corneal healing › 1 · Growth factors & blood derivatives › Thymosin β4 — RGN-259
Thymosin β4 — RGN-259
Synthetic regenerative peptide (43 aa) · RegeneRx / ReGenTree / HLB Therapeutics · not marketed
Oxford II
Investigational
Future · mixed pivotal results
Mechanism of actionPeptide that sequesters G-actin: promotes epithelial migration/adhesion, anti-inflammatory effect (↓NF-κB), anti-apoptotic, nerve regeneration and reduced fibrosis (multimodal action).
Indications (trials)Neurotrophic keratopathy (PED) and dry eye disease.
Route & dosage0.1% eye drops, ~4–6×/day for several weeks (preservative-free).
Level of evidenceOxford II but mixed/negative pivotal results · Scale: Investigational (not approved). One positive phase III RCT in neurotrophic disease (2022), but the confirmatory phase III SEER-3 missed its primary endpoint (June 2025) — strong placebo response.
| FDA | No — investigational (phase III). |
|---|---|
| EU MA | No — investigational. |
| France | Not available (trials). |
| USA | Phase III ongoing; not marketed. |
| Asia | Strong South Korean sponsorship (HLB); not approved. |
Key studies: Sosne G, Kleinman HK et al., phase III RCT in neurotrophic keratitis, Int J Mol Sci 2022 — PMID 36613994; SEER-3 (missed primary endpoint, 2025, results not yet published in a peer-reviewed journal); ARISE dry eye program (mixed results, not peer-reviewed published).
See also: Gabison E. “Corneal wound-healing agents”. In: SFO 2023 Report — Médicaments et biothérapies en ophtalmologie, chapter 21. Full text, open access (in French).