Wound healing trajectories as predictors of effectiveness of therapeutic agents

Abstract

Background: One goal of wound healing research is to discover agents to accelerate healing. Regulatory agencies have suggested stringent criteria to determine efficacy, that of 100% wound closure. Data analysis at a single point such as 100% closure does not provide detailed information about agent effectiveness over the entire span of healing.

Hypothesis: Wound healing trajectories can provide such information and can be used to demonstrate utility as alternative end points for wound healing trials.

Design: Data from 160 patients in 11 clinical trials of diabetic foot ulcers conducted at 2 centers were evaluated. Wound healing trajectories were constructed for patients whose wounds healed (100% closure) and those whose did not (<100% closure) over a 20-week period. The percentage of patients achieving total healing vs time of treatment was plotted and divided into patients receiving a test agent or placebo.

Results: The healing trajectories were almost identical for patients achieving complete healing at the 2 centers, as were the trajectories for patients with less than 100% closure. However, the trajectories of patients achieving total healing were significantly different from those not achieving 100% closure. Fifty-two percent of all patients achieved 100% healing by 20 weeks; 61% of patients receiving an experimental agent had total healing compared with 39% of placebo-treated patients. Linear regression suggested that all patients would achieve total healing by 37 weeks.

Conclusions: Since wound healing trajectories for diabetic foot ulcers treated at 2 centers so closely mimic one another, trajectories might be useful efficacy end points, and used to compare significant points along a continuum rather than a single static end point. Shifting of the wound healing trajectory from an impaired to a more ideal course may be considered when determining efficacy of new wound treatments.