656. Cryptosporidiosis in Immunocompromised Patients with Cancer Receiving Chemotherapy, CAR-T Cell Therapy and Hematopoietic Stem Cell Transplantation: A Retrospective Analysis

BACKGROUND: Cryptosporidium is a parasitic protozoan that causes severe and potentially life-threatening diarrheal disease in immunocompromised patients. Infections can be asymptomatic, cause self-limited disease, or chronic diarrhea and in some cases result in biliary and pulmonary disease METHODS: We performed a detailed retrospective analysis of patients that presented with diarrheal illness, and Cryptosporidium infection diagnosed by GI multiplex (Biofire) at UT MD Anderson Cancer Center between January 2017 and March 2023. RESULTS: We identified 51 patients aged 24 to 89 years with cryptosporidiosis. Hematological malignancies (HM) were present in 44% of patients, while non-hematological malignancies (NHM) in 55%. Thirty-seven percent of patients had received hematopoietic stem cell transplantation (HSCT), 8% chimeric antigen receptor T-cell (CAR-T) therapy, 18% immunosuppressive therapy, and 65% received chemotherapy in the last 90 days. Two patients had human immunodeficiency virus (HIV). All patients presented with diarrhea, 39% with nausea, 43% with abdominal pain, and 51% had fever. The median duration of symptoms was 3 days. About 41% were severely neutropenic, and 61% had severe lymphopenia. Computed tomography (CT) abdomen was normal in 43% of patients, 16% had colitis, 12% had enteritis, and 4% had enterocolitis. All patients were treated with Nitazoxanide, with a median duration of therapy (DOT) of 14 days. The DOT was longer in HM than in NHM (14 ± 7.9 vs. 9.9 ± 5.6, p= 0.016) and in HSCT/CAR-T patients than without HSCT/CAR-T (13.8 ± 6.1 vs. 10.3 ± 7.3, p = 0.009). About 18% of patients had co-infections with other enteropathogens. Death from other causes occurred in 13 of 51 (23%) of patients. All cause mortality between HM and NHM (p=0.207), HSCT/CAR-T and non-HSCT/CAR-T (p=0.52), or chemotherapy vs. without chemotherapy (p=0.34) was similar. Most infections were encountered in the month of October. [Figure: see text] [Figure: see text] [Figure: see text] CONCLUSION: We observed a limited response to nitazoxanide at our center, contributing factors and confounders included co-infections with other pathogens, active chemotherapy, or HSCT/CAR-T induced intestinal epithelium injury. Controlled, double blinded studies with new agents are needed to determine the optimal management of cryptosporidiosis in this population. DISCLOSURES: Pablo C. Okhuysen, M.D., FACP, FIDSA, Astra Zeneca: Stocks/Bonds|Beam Therapeutics: Stocks/Bonds|Biontech: Stocks/Bonds|Deinove Pharmaceutucals: Grant/Research Support|Ferring: Advisor/Consultant|GSK PLC: Stocks/Bonds|Haleon: Stocks/Bonds|Johnson and Johnson: Stocks/Bonds|Melinta Pharmaceuticals: Grant/Research Support|Merk Sharp and Dohme: Grant/Research Support|Moderna: Stocks/Bonds|Napo Pharmaceuticals: Advisor/Consultant|Napo Pharmaceuticals: Grant/Research Support|Novavax: Stocks/Bonds|Pfizer: Stocks/Bonds|SNIPR Biome: Advisor/Consultant|Summit Pharmaceuticals: Grant/Research Support