S5017 The Cost of Control: A Case of Pneumocystis Pneumonia While on Upadacitinib for Crohn’s Disease

Introduction: JAK inhibitors (JAKi) are increasingly used for management of inflammatory bowel disease (IBD); however, they can be associated with an increased risk of serious infection. Previous data suggests a low risk of Pneumocystis jirovecii pneumonia (PJP) in IBD patients on advanced therapies, however this risk with use of JAKi is unknown. We describe a patient with Crohn’s disease diagnosed with PJP after being started on Upadacitinib (UPA). Case Description/Methods: A 58-year-old man with history of ileocolonic Crohn’s disease with complex perianal fistulizing disease on 3 months of induction UPA was admitted for acute hypoxic respiratory failure. He previously had an inadequate response to infliximab, ustekinumab and adalimumab. Evaluation showed bilateral ground glass opacities and positive serum Beta-D-glucan. A diagnosis of PJP was made. He was started on bactrim with symptomatic response and discharged. His UPA was discontinued and he was transitioned to golimumab with continued PJP prophylaxis. Discussion: Prior studies have shown that the risk of PJP in IBD is low. One study noted only 3 cases of PJP in a cohort of 937 patients with IBD. This was despite the uncommon use of prophylaxis and suggests that the risk of PJP in this population is rare and prophylaxis is not warranted on a routine basis. Risk factors associated with PJP use in patients with IBD include older age, steroid use, lymphopenia, and other comorbidities. Prior case reports have detailed episodes of PJP while on JAKi, both in the rheumatologic and IBD populations. A case by Chin et al. details a patient with UC and primary sclerosing cholangitis who developed PJP 3 months after starting UPA. Our case highlights the importance of considering PJP risk in patients with IBD on JAKi, particularly in elderly patients on concomitant immunosuppressants with other comorbidities. Further research is needed to determine the risk of PJP in patients with IBD on JAKi, as well as when prophylaxis is warranted.