 SIMPADICO was a multicenter, randomized, double-blind, placebo-controlled trial that enrolled 553 patients with claudication at 50 sites in Canada and the United States. The mean SD patient age was 6710 years; 72 were males. The duration of claudication was 6.06.1 years at entry; 91 had a history of smoking and 34 were current smokers; 36.5 had diabetes. Resting ABI was 0.590.14; baseline ICD was 132104 and ACD 307209 meters. Results showed that there was no increase in ACD or ICD at 26 weeks with immune modulation therapy IMT using the CelacadeTM system, Vasogen Inc. compared to placebo and no measurable improvement in quality of life with IMT compared to placebo. However, there was a significant decrease in CRP high sensitivity assay in in the IMT group compared to the placebo group. Conclusion: Immune modulation therapy did not improve walking distance in patients with symptomatic peripheral arterial disease but the decrease in CRP suggests a biologic effect of IMT and will warrant further study. 