Weighing the Risks and Benefits of Pneumocystis Jirovecii Pneumonia Prophylaxis in Rituximab Users

Severe infections are a leading cause of morbidity, hospitalization, and mortality for patients with rheumatic diseases. In a recent clinical trial in antineutrophil cytoplasmic antibody (ANCA) – associated vasculitis (AAV), for instance, over 20% of participants had ≥ 1 serious infection over 44 months (1), and in a recent giant cell arteritis trial, up to 12% of participants had a serious infection over 12 months (2). Several factors in fl uence the risk of severe infection, including patient age, the immunologic target(s) of the treatment, the presence of end-organ damage related to the rheumatic disease (e.g., lung or kidney disease), and the patient ’ s comorbidities. Preventing Pneumocystis jirovecii pneumonia (PJP) is of particular interest for rheumatologists. PJP is often severe among patients with rheumatic diseases, with mortality rates exceeding 40% (3). Prophylaxis with trimethoprim/sulfamethoxazole (TMP/SMX) has been associated with reduced mortality in this population (4,5). Acknowledging this, the recent American College of Rheumatology (ACR)/Vasculitis Foundation (VF) guideline for the management of AAV conditionally recommends prophylaxis to prevent PJP in patients receiving rituximab or cyclophosphamide treatment (6).