Small interfering RNA microneedle patches versus silicone sheets in reducing postoperative scars: a randomized single-blinded intraindividually controlled clinical trial

Abstract Background A common complication of wounds is the excessive production of fibrotic scar tissue, which can lead to hypertrophic scars or keloids. Currently, no treatments with good evidence for preventing excessive scar tissue formation are available. We explored the use of microneedle patches containing small interfering RNA (siRNA) to inhibit SPARC mRNA in reducing the volume of postoperative scars. Objectives To compare differences in postoperative scar volume with the daily application of siRNA-embedded dissolving microneedle patches vs. silicone sheets. Methods This was an 8-week, single-blinded intraindividually controlled randomized trial at a tertiary dermatological centre. Patients with 2-week-old postoperative wounds were included. Each half of the scar was randomly assigned to the microneedle patch or silicone sheet. Three-dimensional (3D) volumes were obtained from the scars via a high-resolution scanner at days 0, 30 and 60. The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12622000558729). Results At day 30, scars treated with microneedle patches had a lower geometric mean volume of 0.79 mm3 vs. scars treated with silicone sheets, with a difference in mean percentage volume reduction of 10.7%. At day 60, scars treated with microneedle patches had a statistically significant lower volume (8.88 mm3) compared with the side treated with silicone sheets (12.77 mm3; P = 0.005), with a difference in mean percentage reduction of 9.7%. Additionally, there was also a statistically significant difference between the percentage reduction in scar volume vs. baseline on the side treated with microneedle patches (mean 83.8%) compared with the side treated with silicone sheets (mean 74.1%). Conclusions There was a significantly greater reduction in the volume of postoperative scars on the side of the scar treated with microneedle patches compared with the side treated with silicone sheets. This demonstrates the use of transdermal gene-silencing technology in scar inhibition and that siRNA microneedle patches can be effective and safe in reducing scar tissue formation.