Clinical trial NCT00598871: A Phase 2 Study of the Safety and Efficacy of Thymosin Beta 4 for Treating Corneal Wounds
Official title: A Randomized, Double-Mask, Placebo-Controlled, Dose Response, Phase 2 Study of the Safety and Efficacy of Thymosin Beta 4 in the Treatment of Diabetic Patients' Corneal Wounds Resulting From Epithelial Debridement During Vitrectomy
Study type: INTERVENTIONAL
Overall status: TERMINATED
Phase: PHASE2
Conditions: Diabetes
Keywords: Thymosin beta 4
Corneal wound healing
Vitrectomy
Diabetes
Lead sponsor: ReGenTree, LLC
Sponsor class: INDUSTRY
Collaborators: name: PPD Development, LP
First posted: 2008-01-23
Enrollment: 12
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: As a consequence of damage to multiple organ systems throughout the course of their disease, diabetic patients suffer a number of chronic complications giving rise to increased morbidity, mortality, and health care costs specific to this population. Within the ophthalmic domain, diabetic retinopathy (DR) frequently induces serious visual impairment. Although DR can be addressed surgically, surgery remains a less than ideal intervention within this population with a well-characterized compromised ability to heal. The introduction of a therapeutic agent that could accelerate wound closure and decrease healing time, thereby reducing the risk and incidence of infection and corneal scarring in these susceptible patients, would represent a significant clinical and pharmacoeconomic advance in the treatment of this condition.

Detailed description: In individuals with certain clinical conditions, such as diabetes, corneal epithelial defects persist and do not necessarily respond to conventional treatment regimens because of delayed epithelial wound healing. While wound closure should occur following an injury to the corneal epithelium, a timely re-establishment of the epithelial barrier is of utmost importance.

The wound repair process is intricately linked to a complex inflammatory response that must be properly regulated to ensure healing and optimal visual outcome. Infiltration of inflammatory cells into injured corneal tissue is a hallmark of wound repair, and the association of polymorphonuclear (PMN) leukocyte infiltration with sterile corneal ulceration is well recognized. Retardation of epithelial recovery by persistent inflammation, release of enzymatic products from degranulating PMN, and stimulation of mononuclear leukocytes by cytokines all contribute to poor re-epithelialization.

It has been shown that diabetic corneas manifest reduced rates of epithelial healing after denudement. Yet, in the diabetic patient, not only is the rate of corneal epithelial healing of clinical concern, abnormalities inherent in the diabetic corneal epithelial cytoarchitecture can cause substantial impediments to normal stromal healing. Histologically, diabetic corneas typically demonstrate thickening of the epithelial basal membrane (BM), decreased number of hemidesmosomes, and decreased number of nerve fiber endings. Studies of BM changes in diabetic corneas have yielded information regarding poor adhesion of the epithelial BM to the stroma. During vitrectomy in diabetic patients, when the cornea epithelium is removed, it separates as an intact sheet and the entire thickened BM, characteristic of diabetes, adheres to the epithelium. In contrast, when normal epithelium is removed by scraping, the BM remains adherent to the stroma.

Because patients with diabetic retinopathy (DR) corneas have delayed wound healing, the expression of thymosin beta 4 (Tβ4) as a potent epithelial cell migration stimulator in DR corneas was investigated. Human DR corneas were analyzed and were found to express significantly less Tβ4 compared to normal corneas, suggesting that the use of Tβ4 may accelerate the wound-healing process in this model.

Eligibility criteria: Inclusion Criteria

* Type 1 or Type 2 diabetes mellitus.
* Patients who have an expected minimum 50% likelihood of requiring corneal epithelial debridement in the opinion of the Investigator Size of wound should be 8 mm.
* Signed written informed consent by patient or legal guardian.

Exclusion Criteria

* Have current or history of herpetic eye disease in the past 3 years.
* Display evidence of keratitis.
* Have Sjögren's syndrome.
* Have corneal scarring, opacity, or dystrophy.
* Have a history of malignancy.
* Have a history of HIV or AIDs
* Are pregnant or lactating females.
* Are females who can become pregnant.
* Have a known hypersensitivity to the study drug.
* May be regarded as unreliable for the study.
* Have previously participated in this study.
* Experience any complication during the vitrectomy procedure itself, which will exclude the patient from participating in this study.

Primary outcomes:
measure: Number of Participants With Treatment Emergent Adverse Events (TEAEs) After Treatment With Thymosin Beta 4 in the Target Eye of Diabetic Patients During Vitrectomy
timeFrame: 14 days
Secondary outcomes:
measure: Number of Participants With Corneal Epithelial Wound Healing at Day 14 (End of Treatment)
timeFrame: 14 days
Other outcomes:
Locations:
city: Inglewood
country: United States
facility: United Medical Research Institute
state: California
city: Los Angeles
country: United States
facility: Doheny Eye Institute
state: California
city: Orlando
country: United States
facility: Magruder Eye Institue
state: Florida
city: Augusta
country: United States
facility: Southeast Retina Center
state: Georgia
city: Asheville
country: United States
facility: Western Carolina Retinal Associates, PA
state: North Carolina
Study officials:
affiliation: RegeneRx Biopharmaceuticals, Inc.
name: David R Crockford
role: STUDY_DIRECTOR
References: