Phase II Randomized, Double-Blind, Placebo-Controlled Study of BMS-188667 (CTLA4Ig) in Patients With Psoriasis Vulgaris

Inclusion Criteria: * Diagnosis and documentation of a history of stable psoriasis vulgaris of at least 6 months duration. * vulgaris total body surfae area involvement of at least 10% * Failure for toxicity and/or inefficacy of at least one standard anti- psoriatic therapy including topical treatment, phototherapy, photochemotherapy, methotrexate, cyclosporin A or etretinate. Exclusion Criteria: * Male and female subjects who are not willing to receive adequate counseling and exercise adequate contraceptive measures with enrolle on study. * Functional class (V (ACR) RA or amyloidosis) * Active vasculitis (except for subcutaneous rheumatoid nodules). * Subjects with a history of asthma, angioedema or anaphylaxis. * Subjects with evidence of active or latent bacterial or viral invedtions. * Subjects with a history or malignancy (except basal cell or superficial squamous cell skin carcinoma). * body weight \> 100 kg (or 220 lbs.)