Hereditary angioedema (HAE) with C1 esterase inhibitor deficiency is an autosomal dominant, potentially life-threatening disease, characterized by recurrent self-limiting bouts of edema involving mainly extremities, genitalia, the face, the intestine and the airways. The prevalence of HAE is in the range from 1:10,000 to 1:150,000 in the general population. HAE is frequently misdiagnosed, with delays of 8-10 years from onset of initial symptoms to diagnosis. Lanadelumab (DX-2930) is a fully human IgG1 monoclonal antibody against plasma kallikrein (pKal, KLKB1), showing a potent and selective inhibition of pKal in the pM range, which by subcutaneous route in a proof-of-concept clinical trial showed long-lasting efficacy and tolerability as a prophylactic treatment for HAE. Two phase III studies to assess the efficacy and safety of DX-2930 to prevent angioedema attacks in HAE patients are ongoing. DX-2930 received orphan drug designation from the European Medicines Agency and the U.S. Food and Drug Administration (FDA), as well as FDA fast track and breakthrough therapy designations for the prevention of attacks of HAE.