Study of CRx-191 to Assess Activity in Plaque Psoriasis

CRx-191 is a proprietary synergistic combination drug candidate being evaluated by CombinatoRx for topical psoriasis therapy. CRx-191 was identified via a proprietary screening assay for novel drug combinations demonstrating enhanced inhibition of tumor necrosis factor- alpha and interferon-gamma release, cytokines that are implicated in the pathogenesis of psoriasis. This clinical trial will assess the effectiveness of CRx-191 in reducing the psoriatic infiltrate band thickness as measured by transdermal ultrasound. All subjects will receive all treatments in separate test fields, with intra-individual comparison of the treatments.