1024. Evaluation of Atovaquone Prescribing for Pneumocystis jiroveci Pneumonia (PJP) Prophylaxis

BACKGROUND: Trimethoprim-sulfamethoxazole (TMP-SMX) use for PJP prophylaxis has been associated with a variety of adverse reactions including myelosuppression, hypersensitivity reactions, acute kidney injury, and hyperkalemia. Atovaquone is used as an alternative drug, but it has several disadvantages, such as breakthrough PJP risk, dysgeusia, and higher cost compared with TMP-SMX. Indications for atovaquone prophylaxis at our institutions include severe cytopenias, hypersensitivity, renal impairment, or hyperkalemia. We evaluated atovaquone use and compliance with institutional PJP prophylaxis guidelines. METHODS: This was a retrospective study of inpatient atovaquone prescribing for PJP prophylaxis at Brigham and Women’s Hospital and Dana-Farber Cancer Institute from 7/1/18 to 9/30/18. We included adult patients who received ≥1 dose of atovaquone and ≥3 months of PJP prophylaxis with any agent. The primary endpoint of this study was the proportion of patients who could have been safely switched to TMP-SMX 3 months after atovaquone initiation. Other endpoints included the incidence of breakthrough PJP, reasons for TMP-SMX avoidance, and estimated cost savings. RESULTS: Two-hundred and eighteen patients were evaluated and 164 were included. Most common indications for atovaquone prophylaxis were bone marrow transplant (44.5%), solid-organ transplant (30.5%) and use of immunosuppressive agents (21.9%). Atovaquone was started in 145 patients (88.4%) according to institutional guidance. Three months after initiation, 89 patients (45.7%) could have been safely switched to TMP-SMX. Failure to timely change to TMP-SMX was associated with 1,615 additional patient-days of atovaquone therapy and $103,683 in excess costs within 3 months of initiation. Major reasons for TMP-SMX avoidance were thrombocytopenia (51.3%), neutropenia (35.4%), renal impairment (31.7%), allergy history (26.8%), and hyperkalemia (19.5%). No breakthrough PJP infections were observed while patients were on atovaquone. CONCLUSION: Institutional-guideline compliance was high during atovaquone initiation. However, after 3 months, many patients who could have been safely transitioned to TMP-SMX continued to receive atovaquone. This resulted in excess costs and potentially sub-optimal therapy. DISCLOSURES: All authors: No reported disclosures.