Fused PCSK9-TT peptide immunization significantly reduced the level of PCSK9 in plasma of mice. AT04A and AT06A from AFFITOPE® peptide were selected to induce production of anti-PCSK9 antibody in patients with hypercholesterolemia in the phase I study NCT02508896. Only AT04A showed significant LDLc-lowering activity. Here, PCSK9 is linked to Hypercholesterolemia.