Comprehensive, Multimodal Characterization of an Imiquimod-Induced Human Skin Inflammation Model for Drug Development.

van der Kolk T, Assil S, Rijneveld R, Klaassen ES, Feiss G, Florencia E, Prens EP, Burggraaf J, Moerland M, Rissmann R, van Doorn MBA

Imiquimod (IMQ) is often used as a topical challenge agent to provoke local skin inflammation. The objective of this study was to develop and refine a rapid, temporary, and reversible human skin inflammation model with IMQ for application in clinical drug development. A randomized, vehicle-controlled, open-label, dose-ranging study was conducted in 16 healthy male subjects. IMQ (5 mg) was applied once daily for 72 hours under occlusion to intact skin (n = 8) or tape stripped (TS) skin (n = 8). Although IMQ alone induced limited effects, TS+IMQ treatment showed larger responses in several domains, including erythema and perfusion (P < 0.0001), mRNA expression of inflammatory markers (P < 0.01), and inflammatory cell influx compared with vehicle. In conclusion, a rapid, human IMQ skin inflammation challenge model was successfully developed with a clear benefit of TS prior to IMQ application. Future interaction studies will enable proof-of-pharmacology of novel compounds targeting the innate immune system.