Efficacy and Safety of 0.25% Timolol Gel in Enhancing Full Thickness Skin Grafts Healing and Cosmetic Outcomes (FTSG)

Efficacy and Safety of 0.25% Timolol Gel in Enhancing Full Thickness Skin Grafts Healing and Cosmetic Outcomes

Efficacy and Safety of 0.25% Timolol Gel in Enhancing Full Thickness Skin Grafts Healing and Cosmetic Outcomes: A Randomized, Controlled Trial

Due to the insufficient accrual rate and strategic reasons to focus our efforts on higher impact research projects.

The use of topical beta-blockers, such as 0.25% timolol, in promoting wound healing is currently emerging in the academic literature. The investigators will enroll 82 patients who have their skin cancer surgically removed resulting in the need of a full-thickness skin graft. The objective of this randomized safety study is to determine the safety and efficacy of 0.25% timolol in promoting wound healing in full-thickness skin grafts compared to standard of care.

The role of topical beta-blockers in promoting wound healing is currently emerging in the international literature. β2-Adrenergic receptors (B2AR) are the only subtype of beta-adrenoceptors expressed on skin. They can be found in secretory coil of apocrine glands, keratinocytes, fibroblasts and melanocytes. The distribution of these receptors provides insight on dermatological disorders that may be affected by β-blockers. Keratinocyte migration occurs by the facilitation of chemotaxis, the polarization of cells, and activation of extracellular signal-related kinases essential in the signaling of promigratory pathways. The B2AR activation inhibits keratinocyte migration by activating the serine/threonine phosphatase-2a, which downregulates phosphorylation of extracellular signal-related kinases necessary for migration. Therefore, B2AR antagonists prevent the phosphorylation of phosphatase-2a and have the downstream effect of extracellular signal-related kinase promotion, inducing a promigratory pathway in keratinocytes. Keratinocyte migration also occurs by galvanotaxis, a phenomenon in which cells migrate in response to electric stimuli. Keratinocytes can be stimulated to migrate with the formation of electrical poles and the application of electrical fields. The B2AR antagonists improve the ability of keratinocytes to respond to such migratory cues, whereas the B2AR agonists decrease keratinocytes' ability to respond, further implicating the use of topical timolol for recalcitrant wounds. Angiogenesis and dermal fibroblast proliferation are also regulated by B2ARs. The B2AR antagonists have been found to promote angiogenesis in chick chorioallantoic membrane assays and in vivo murine wound models. Dermal fibroblast migration is also increased (by 27%) when exposed to B2AR antagonists, and epidermal differentiation is improved with B2AR antagonists and β1- and β2-receptor antagonists. Full-thickness skin grafts (FTSG) are one of the most commonly performed procedures in dermatologic, plastic and burn surgery. Various experimental approaches to optimize the healing of FTSG receiving sites have been described; however, no clearly superior and easily applicable method has gained wide acceptance in daily practice. As indicated by preliminary evidence in other wound healing endeavors, 0.25% timolol gel may represent a commercially available, safe and simple, painless and relatively inexpensive treatment for improving healing of FTSG receiving site, as well as for improving cosmetic long term outcomes. To assess the efficacy and safety of topically applied 0.25% timolol gel in promoting wound healing in FTSG receiving site versus standard of care (SOC) by: Evaluating healing in response to treatment with 0.25% topical timolol gel versus SOC in terms of wound surface area and Graft Take Score at the receiving site of a FTSG at 7 and 14 days; Evaluating cosmetic outcomes of the receiving site of a FTSG in terms of blinded physician (Vancouver Scar Scale, VSS) and patient (Visual Analogue Scale, VAS) assessment at 3 and 6 months' follow up; Evaluating the need for further scar revision (dermabrasion or pulsed dye laser [PDL]) at the 6-month follow up; Evaluating patient discomfort during the healing process by means of a patient pain VAS; and Determining the side effects associated with 0.25% timolol gel versus SOC

The protocol will begin post-surgery. Eligible subjects will be assigned by computer-based randomization to case (0.25% timolol gel) or control (standard of care [SOC]) group and treated as follows: Receiving site of FTSG/case group: During surgery: application of 0.25% timolol gel (2 drops per cm2) on wound bed before FTSG is placed During surgery: application of 0.25% timolol gel (2 drops per cm2) over FTSG after insetting of the graft After bolster removal (7 days): daily cleansing and daily 0.25% timolol (2 drops per cm2) application for 4 weeks Receiving site of FTSG/control group: FTSG surgery as per SOC After bolster removal (7 days): daily cleansing and daily Vaseline application for 4 weeks

During surgery: application of 0.25% timolol gel (2 drops per cm2) on wound bed before FTSG is placed During surgery: application of 0.25% timolol gel (2 drops per cm2) over FTSG after insetting of the graft After bolster removal (7 days): daily cleansing and daily 0.25% timolol (2 drops per cm2) application for 4 weeks

FTSG surgery as per SOC After bolster removal (7 days): daily cleansing and daily Vaseline application for 4 weeks

A study physician will review the healed scar site to determine if there are potential cosmetic factors that could be improved through scar revision. If the patient is interested in having scar revision procedures, the study physician will offer a dermabrasion or PDL to treat the scar site.

Physician blinded to subject's treatment group uses VSS which documents scar appearance change over time via photos. VSS ranges from 0 (most desirable outcome) to 13 (least desirable). A lower score is considered a better outcome and a higher score is a worse outcome. VSS consists of 4 sub-scales, with each reporting a value. The "pigmentation" ranges from 0 (normal pigment) to 2 (hyperpigment); "vascularity" ranges from 0 (normal appearance) to 3 (purple appearance); "pliability" ranges from 0 (normal) to 5 (contracture); "height" ranges from 0 (normal/flat) to 3 (>5mm). Sub-scale scores are combined to give an overall VSS score.

Scar VAS rates subjects' graft cosmetic appearance. Each question ranges from 1 (no complaints w/ itch or pain/as normal skin) to 10 (worst imaginable itch or pain/very different from normal skin). Ranges from 6 (best outcome score) to 66 (worst outcome score); a lower score is considered a better outcome and a higher score is considered a worse outcome.

Evaluating change in healing response to treatment with 0.25% topical timolol gel versus SOC in terms of wound surface area at the receiving site of a FTSG via Graft Take Score

The Graft Take Score will be used to assess amount of graft take at each visit. Graft take is considered "Good" if 90%+ of the graft site is healed and pink/purple in color; "Moderate" if there is 50% healing, pink or purple in color, and >50% of the graft has taken; and "Poor" if <50% graft take.

Evaluating change in healing response to treatment with 0.25% topical timolol gel versus SOC in terms of wound surface area at the receiving site of a FTSG via histogram planimetry

Histogram planimetry is more accessible than automated analysis software programs, and it is based on the pixel count of a selected irregular area which is divided by the pixel count of 1 cm2 to find a result in terms of cm2 or mm2.

Subjects will be asked to complete a Visual Analogue Scale for scar assessment to rate how they think their graft sites appear cosmetically compared to normal skin, and any complaints about how painful they sites are, and how itchy they feel. Each question ranges from 1 (no complaints with itch or pain/as normal skin) to 10 (worst imaginable itch or pain/very different from normal skin). The score ranges from 6 (best outcome score) to 66 (worst outcome score), thus a lower score is considered to have a better outcome and a higher score is considered a worse outcome.

7 days' post-surgery, 14 days' post-surgery, 30 days' post-surgery, 3 months' post-surgery, 6 months' post-surgery

Determining change in the side effects associated with 0.25% timolol gel versus SOC via physician assessment

A physician will assess for side effects and determine whether they are likely associated with the 0.25% topical timolol or part of the normal wound healing experience.

7 days' post-surgery, 14 days' post-surgery, 30 days' post-surgery, 3 months' post-surgery, 6 months' post-surgery

Determining change in the side effects associated with 0.25% timolol gel versus SOC via patient assessment

7 days' post-surgery, 14 days' post-surgery, 30 days' post-surgery, 3 months' post-surgery, 6 months' post-surgery

Inclusion Criteria: Age ≥18 years of age Undergoing a procedure which results in the need of a FTSG Willing to provide written informed consent Exclusion Criteria: Age less than 18 years of age Pregnant women (Use of systemic drugs that can impede wound healing, such retinoids or immune-suppressive drugs) Severe coagulation disorders Severe, uncontrolled systemic comorbidities, such as diabetes, arthritis, etc. Hypersensitivity to 0.25% timolol gel Not willing to provide written informed consent