A RANDOMIZED, CONTROLLED TRIAL TO STUDY THE EFFICACY AND SAFETY OF C1INHIBITOR CONCENTRATE IN TREATING HEREDITARY ANGIOEDEMA

BACKGROUND: No effective treatment exists in the United Stales for acu te attacks of hereditary angioedema (HAE). STUDY DESIGN AND METHODS: T o evaluate the efficacy and safety of C1 inhibitor concentrate in trea ting HAE, a large primary care and referral center hospital conducted a randomized, placebo-controlled, double-blind trial with intent-to-tr eat analysis. Of the 36 patients enrolled in the study, 23 received tr eatment, and 22 completed the trial. C1 inhibitor concentrate or album in (placebo) infusions were administered in a blind fashion to HAE pat ients who came to the hospital for treatment no later than 5 hours aft er an attack began. RESULTS: Relief was almost twice as fast in person s receiving C1 inhibitor concentrate than in the controls: 7.62 hours (mean; SD 7.08) versus 15.35 hours (mean; SD 8.31), respectively. The difference for time-to-relief was highly significant (p = 0.007, Mann- Whitney U test). The median time-to-relief was 6.17 hours (interquarti le range 0.33-15.35) in the treatment, group and 15.35 hours (interqua rtile range 14.00-22.83) in the control group. Resolution of symptoms was one-third faster in the C1 inhibitor concentrate group than in the placebo group: 23.98 hours (mean; SO 14.81) and 34.58 hours (mean; SD 13.56), respectively (p = 0.09, Mann-Whitney U test). Recovery of fun ctional C1 inhibitor was 119.65 percent (mean; SD 50.80), and half-lif e was 37.87 hours (mean; SD 19.75). Recovery of antigenic C1 inhibitor was 147.75 percent (mean; SD 97.68), and half-life was 24.01 hours (m ean; SD 9.70).There were no viral infections or serious adverse effect s from the drug after 70 attacks in the treatment group and 96 attacks in the control group. CONCLUSIONS: C1 inhibitor concentrate is a safe , effective treatment for acute attacks of HAE.