Thymosin beta 4 shows promise for recalcitrant neurotrophic defects

This small case series evaluated the clinical benefit of adding thymosin beta 4 eye drops to the treatment regimens of four patients with longstanding neurotrophic corneal epithelial defects due to herpes zoster ophthalmicus, diabetes or both. Following an encouraging unpublished preliminary evaluation of thymosin beta 4 in diabetic corneal defects, the authors sought to evaluate thymosin beta 4 in a human disorder that did not have an infectious component or one in which stem cell dysfunction or conjunctival disruption was extensive.

Under an FDA investigational new drug compassionate use protocol, each patient received a sterile, single-dose, nonpreserved, ophthalmic formulation of thymosin beta 4 drops supplied by RegeneRx Biopharmaceuticals, Inc. (Rockville, Md). They were followed for one month, since this period allowed for monitoring of both healing and subsequent surface breakdown after cessation of treatment.

All four patients experienced clinically significant reduction in the size of their epithelial defects. No evidence of stromal thinning or vascular ingrowth of the corneal stroma on the iris surface or retina was observed in any patients. None of them reported discomfort associated with the drops. Improved ocular comfort and decreased conjunctival injection was correlated with healing.

The authors conclude that these results suggest a promising role for thymosin beta 4 drops in the treatment of patients with recalcitrant, nonhealing, neurotrophic corneal epithelial defects.