469. Outcomes of COVID-19 among hospitalized patients under Rituximab: the experience of a Portuguese hospital

BACKGROUND: Rituximab (RTX) is a monoclonal antibody commonly used for various hematological and autoimmune disorders. B-cell–depleting therapies also blunt humoral responses to SARS-CoV-2 vaccines. Whether this carries an increased risk of hospitalization or death from COVID-19 is unclear. METHODS: We conducted a retrospective study of hospitalized patients with COVID-19 who received RTX prior to hospitalization (maximum 18 months before). We analysed their outcomes, including length of stay, antiviral treatment, inflamatory markers and mortality. RESULTS: A total of 43 hospitalized COVID-19 patients who received RTX were included in the study (from April 2020 to April 2023) . The median age was 67 years (range, 25-88), and 58% were female. The average length of stay was 28 days (range, 1-29). Upon admission, average value of severity predictor markers: CRP 94.6 mg/L, procalcitonine 0.66 ng/mL, lactate dehydrogenase (LDH) 383.5 U/L, D-dimers 1530.3 ng/mL. Treatment was performed in 44% with dexamethasone and in 48% with remdesivir. The mortality rate was 42%. CONCLUSION: In our study, previous treatment with rituximab was associated with high severity predictor markers and serious outcomes of COVID-19. Patients and healthcare professionals should be aware of the risk associated with COVID-19 in this population. Clinicians must choose carefully patients for anti-CD20 treatments. Preventive measures, active and passive immunization, as well as early antivirals therapy may decrease COVID-19 severity. DISCLOSURES: All Authors: No reported disclosures