1556. Infectious Disease Complications with Use of Checkpoint Inhibitors in Solid Organ Malignancies

BACKGROUND: Immune checkpoint inhibitors (ICIs) are innovative cancer immunotherapies used for solid-organ and hematologic malignancies. ICIs are known for their immune-related adverse events (irAE) but there are limited reports on infectious complications of immunosuppression for these complications. The purpose of this study was to describe the spectrum of infections in patients with melanoma, renal cell carcinoma or non-small cell lung cancer receiving ICI. METHODS: Retrospective review of City of Hope patients with melanoma, renal cell carcinoma or non-small cell lung cancer on nivolumab, pembrolizumab, and/or ipilimumab from January to November 2017 and received two or more doses of ICI. Pt characteristics assessed: age, sex, prior chemotherapy, steroid use, and type of immunosuppression for irAE. Microbiology records were used to identify infections. RESULTS: Thirty-nine infectious episodes (35 bacterial, four viral) were identified among 111 patients. Four bacteremia (two B. cereus, coagulase-negative staphylococcus, 1 S. aureus), 12 urinary tract (10 Gram-negative rods, 2 Gram-positive cocci), one intra-abdominal, eight skin and soft-tissue infections (one S. aureus, one Actinomyces radinge, one E. faecalis, and one E. cloacae). There were two probable viral pneumonias (two rhinovirus, two enterovirus) and no fungal infections. Fourteen (12.6%) infections were defined as serious (requiring intravenous antimicrobials and/or hospitalization). There was no association between the specific malignancy or ICI used and risk of infection. Steroid use was significantly associated with serious infections: 12/14 (85.7%) vs. 27/95 (28.4%); P = 0.0003), and no patients had received infliximab or other immunosuppressant. CONCLUSION: Bacterial infections were most common, and the only risk factor associated with serious infections in our study was steroid use. Type of ICI did not impact the rate of infection. DISCLOSURES: S. Dadwal, Ansun Biopharma: Investigator, Research grant.