Provided herein are plasma kallikrein antibodies binding to active plasma kallikrein and methods of using such antibodies in treating and preventing hereditary angioedema attack, such method may involve a first treatment period and optionally, a second treatment period. Also provided are methods of using such antibodies in treating hereditary angioedema involving a single dose of the antibody to a subject who has undergone a prior HAE treatment, followed by multiple doses of the same antibody if the subject experiences an HAE attack after the single dose.
