RESPONSE OF PSORIASIS TO A NEW TOPICAL RETINOID, AGN-190168

Background: Oral retinoids have been widely used in psoriasis, but top ical forms have been ineffective or irritating. Objective: Our purpose was to determine the clinical and molecular effects of a new topical retinoid, AGN 190168, on psoriasis. Methods: Seven patients with psori asis were treated for 2 weeks with topical retinoid and 2 weeks with v ehicle. Two control subjects with psoriasis were treated for 2 weeks w ith vehicle alone. Biopsy specimens from normal skin as well as from u ntreated and treated psoriatic le sions were compared by immunohistoch emical analysis. Differentiation and inflammatory markers were studied . Results: Clinical improvement was seen in all seven patients after 2 weeks of treatment. Improvement was still present, but not significan t, after 2 additional weeks of vehicle application. Histologic examina tion showed a return to a more normal morphology in four of seven biop sy specimens, which correlated with filaggrin expression. There was a diminution in the precocious expression of keratinocyte transglutamina se, keratin 16, and involucrin, as well as a decrease in epidermal gro wth factor receptor and in the number of cells expressing intercellula r adhesion molecule type 1 and HLA-DR. Conclusion: Clinical and histol ogic improvements were seen in psoriasis m association with the topica l application of AGN 190168 at 2 weeks, including decreased inflammati on and restoration of normal epidermal differentiation. Small patient numbers and the possibility that the changes were related to clinical improvement alone and not the topical agent preclude definitive conclu sions.