Caplacizumab for Acquired Thrombotic Thrombocytopenic Purpura

Thrombotic thrombocytopenic purpura is often caused by an autoantibody to ADAMTS13, resulting in ultralarge von Willebrand factor, which induces platelet aggregation. Caplacizumab blocks platelet aggregation and speeds recovery when combined with plasma exchange. Acquired thrombotic thrombocytopenic purpura (TTP) is a potentially life-threatening thrombotic microangiopathy resulting from systemic microvascular thrombosis and leading to profound thrombocytopenia, hemolytic anemia, and organ failure of varying severity. 1 Acquired TTP is caused by a severe deficiency of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) due to the presence of inhibitory autoantibodies. 2 Decreased ADAMTS13 activity leads to an accumulation of ultralarge von Willebrand factor multimers, which bind to platelets and induce aggregation. 3 These microthrombi cause tissue ischemia and organ dysfunction (commonly involving the brain, heart, and kidneys), resulting in early death 4 , 5 or in . . .