Two Roads Diverge: Treatment Choice in Coexisting Severe Aplastic Anemia and Paroxysmal Nocturnal Hemoglobinuria

Aplastic anemia (AA) is a bone marrow failure syndrome of pancytopenia due to impaired hematopoiesis. It is strongly associated with paroxysmal nocturnal hemoglobinuria (PNH). Each condition can cause the other, or occur simultaneously. There are no guidelines for treating concomitant AA and PNH; immunosuppressive therapy (IST) or hematopoietic stem cell therapy (HSCT) is first-line for the former, and eculizumab is first-line for the latter. New studies suggest that treating AA/PNH together versus sequentially should depend on AA severity. We report the case of a previously healthy male (31-year-old, Nigerian immigrant) who developed jaundice, scleral icterus, easy fatigability, and epistaxis. He was diagnosed with AA on bone marrow biopsy and with PNH on flow cytometry. He initially underwent chemotherapy due to increased infection risk with eculizumab in a neutropenic patient; however, he showed minimal response and thus began eculizumab pending allogeneic stem cell transplant. There are no guidelines for treating patients with both AA and PNH, and clinical decision making is generally individualized based on disease severity. Only one prior publication reported simultaneous treatment with eculizumab and chemotherapy, due to stated concern for pancytopenia, especially neutropenia, being the most immediate cause of morbidity/mortality. This demonstrates the individualized decisions that must be made when treating simultaneous PNH and AA, and the importance of PNH/severe AA patients as a separate subpopulation.