Dose Adjustments of Pegcetacoplan in a Patient With Paroxysmal Nocturnal Hemoglobinuria Undergoing Surgery: A Case Report.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal hemolytic anemia mediated by complement that may present with thrombosis and bone marrow failure. Treatments inhibiting complement component 5, such as eculizumab, improve intravascular hemolysis and anemia and decrease the risk of thrombosis. However, anemia persists in some patients because of extravascular hemolysis. In this context, pegcetacoplan, a pegylated complement component 3 inhibitor, is a valuable treatment option for patients with PNH, as it inhibits both extravascular and intravascular hemolysis, improving anemia. Infections and surgery may trigger complement activation, and dose adjustments of treatments that inhibit complement components may be necessary in these situations to avoid episodes of breakthrough hemolysis. Here, we present a case of a 67-year-old male with PNH who, after initiating pegcetacoplan in 2022, underwent three scheduled surgeries and one emergency surgery. We report the successful use of dose adjustments and close monitoring to prevent breakthrough hemolysis during these perioperative periods.