Pharmacodynamic and pharmacokinetic response to anti-tumor necrosis factor-α monoclonal antibody (infliximab) treatment of moderate to severe psoriasis vulgaris

Objective: Infliximab monotherapy provided a rapid and high degree of clinical benefit in patients with moderate to severe psoriasis in a previously conducted trial. Herein we describe the pharmacodynamic and pharmacokinetic results observed in this clinical trial. Methods: Patients with psoriasis received 5 or 10 mg/kg of infliximab or placebo at weeks 0, 2, and 6. Immunohistochemical analysis of lesional (weeks 0, 2, 10) and nonlesional (week 0) biopsies was conducted. Median infliximab half-life and peak serum concentrations over time were calculated. Results: Infliximab immunotherapy resulted in rapid and dramatic decreases in epidemial inflammation and normalization of keratinocyte differentiation in psoriatic plaques; these changes preceded maximal clinical response. Infliximab concentrations were maintained above the detection limit (0.1 mg/mL) in the majority of patients through week 14. Conclusion: The clinical and immunohistologic data demonstrate a pivotal role for tumor necrosis factor-α in the pathogenesis of psoriasis and support further development of drugs targeting tumor necrosis factor-α.