Randomized Double-Blind Placebo-Controlled Trial Using Recombinant Human Interleukin-10 for Moderate-to-Severe Psoriasis

Several studies have documented an essential role for interleukin-10 (IL-10) in preventing prolonged and exaggerated immune responses to antigens and irritants. Psoriasis, a relatively common disease, is characterized by T cell-mediated inflammation in affected skin. In this study, the safety, tolerance, immunologic effects, and clinical activity of subcutaneous (SC) recombinant human (rh) IL-10 will be evaluated in patients with moderate-to-severe psoriasis. There will be 2 groups of patients, randomized to receive either 20 (micro)g/kg rhIL-10 SC 3 times weekly (20 patients) or SC placebo (10 patients). This double-blind phase will continue for a total of 12 weeks and the principal evaluation will be the comparison between baseline and 12 week Psoriasis Area Severity Index (PASI) scores. Patients will come for an initial screening visit at day 0, and at weeks 1, 2, 4, 6, 8, and 12, with follow-up visits at weeks 16 and 20.

All patients will be offered rhIL-10 at 12 weeks (following the blinded portion of the study protocol). Patients initially receiving active medication who wish to continue rhIL-10 therapy will be kept on the drug. This open-label portion of the study will continue for up to an additional 12 weeks. Patients continuing with active drug will be evaluated at weeks 14, 16, 20, and 24.

Skin disease activity and toxicity will be assessed and recorded throughout the study. In addition, research studies will include functional assays to assess cytokine secretion and immunologic function of peripheral blood cells and immunohistochemical characterization of the inflammatory cells in skin.