2645. Clinical Outcomes of Oseltamivir vs. Baloxavir in Patients Hospitalized with Influenza A

BACKGROUND: Baloxavir marboxil is a new antiviral agent for the treatment of acute uncomplicated influenza in patients > 12 years of age who have been symptomatic for no more than 48 hours. However, clinical trials to date have excluded patients hospitalized with influenza infection. METHODS: This study was a multi-center, retrospective chart review of adult patients admitted to the hospital who received oseltamivir or baloxavir for the treatment of influenza A. Patients were screened for inclusion between January 2018 and February 2018 in the oseltamivir group while patients in the baloxavir group were screened for inclusion between January 2019 and February 2019. Patients who had influenza diagnosed after 48 hours from hospital admission, were not admitted to the hospital, received baloxavir and > 2 doses of oseltamivir during their hospital stay, received > 1 dose of baloxavir during admission for influenza, received influenza therapy prior to admission, died within 48 hours of presentation to the hospital, were asymptomatic at the time of antiviral therapy, or who had left the hospital against medical advice were excluded. Influenza A diagnosis was confirmed by RT–PCR using a nasopharyngeal swab specimen. The primary outcome was hospital length of stay (LOS). RESULTS: Of the 699 patients reviewed, 359 met inclusion criteria. There were 221 patients who received baloxavir and 138 patients who received oseltamivir. Patients who received oseltamivir were older (65 years [55–78] vs. 82 years [69–88], P < 0.01) and were less likely to have a Body Mass Index > 40 kg/m(2) (26 [12%] vs. 7 [5%], P = 0.03) compared with the baloxavir group. For the primary outcome of LOS, the baloxavir group had a shorter LOS compared with oseltamivir (4 days [3–6] vs. 5 days [3–8], P = 0.02). Of the 272 patients who were hypoxic at the time of antiviral administration, the baloxavir group was more likely to resolve their hypoxia (145 [88%] vs. 84 [79%], P = 0.04) and had a shorter time to resolution of hypoxia (43 hours [22–78] vs. 81 hours [33–135], P < 0.001) compared with oseltamivir. CONCLUSION: This study supports the use of baloxavir for the treatment of influenza A in hospitalized patients with possible benefits of reduced length of stay and faster time to resolution of hypoxia compared with oseltamivir. [Image: see text] DISCLOSURES: All authors: No reported disclosures.