Evaluation of safety and clinical activity of multiple doses of the anti-CD80 monoclonal antibody, galiximab, in patients with moderate to severe plaque psoriasis

Background: Reduction in lesional, activated T cells induces improvement in psoriatic plaques. Galiximab (IDEC-114), an IgG₁ anti-CD80 antibody, binds to CD80, a costimulatory molecule involved in T-cell activation. Objective: A Phase I/II, multidose, multischedule, dose-finding study of galiximab to evaluate safety, pharmacokinetics, and clinical activity was conducted in 35 patients with moderate to severe plaque psoriasis. Methods: Seven cohorts of five patients received galiximab intravenously on three different schedules at different dose levels. Results: Adverse events (AEs) commonly occurred as mild and self-limiting. Improvements were observed in most cohorts without evidence of a dose response in Psoriasis Area and Severity Index (50% or greater reduction in PASI score in 40% of patients), Physician's Global Psoriasis Assessment (PGA rating of Good or above in 57% of patients), and Psoriasis Severity Scale (PSS, baseline mean of 7.6 decreased by Study Day 127 to 5.0). An association was observed between reduction in CD3⁺ cell count in histologic studies and reduction in PASI score. No antibodies to galiximab were detected. Conclusion: Galiximab appears to be safe and well tolerated with preliminary evidence of clinical and histologic response.