SERPING1 and hereditary angioedema: Patients randomized to the C1INH(SC) 60 IU/kg twice‐weekly group had a significantly lower rate of HAE attacks/month compared with those randomized to the placebo group (mean [95% confidence interval]: 0.52 [0.00–1.04] vs. 4.03 [3.51–4.55]; p < 0.001).